Commit Graph

1211 Commits

Author SHA1 Message Date
Aleksa Sarai
2b98149c23 namei: only return -ECHILD from follow_dotdot_rcu()
It's over-zealous to return hard errors under RCU-walk here, given that
a REF-walk will be triggered for all other cases handling ".." under
RCU.

The original purpose of this check was to ensure that if a rename occurs
such that a directory is moved outside of the bind-mount which the
resolution started in, it would be detected and blocked to avoid being
able to mess with paths outside of the bind-mount. However, triggering a
new REF-walk is just as effective a solution.

Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Fixes: 397d425dc2 ("vfs: Test for and handle paths that are unreachable from their mnt_root")
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-12-08 19:09:36 -05:00
Linus Torvalds
0aecba6173 Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs d_inode/d_flags memory ordering fixes from Al Viro:
 "Fallout from tree-wide audit for ->d_inode/->d_flags barriers use.
  Basically, the problem is that negative pinned dentries require
  careful treatment - unless ->d_lock is locked or parent is held at
  least shared, another thread can make them positive right under us.

  Most of the uses turned out to be safe - the main surprises as far as
  filesystems are concerned were

   - race in dget_parent() fastpath, that might end up with the caller
     observing the returned dentry _negative_, due to insufficient
     barriers. It is positive in memory, but we could end up seeing the
     wrong value of ->d_inode in CPU cache. Fixed.

   - manual checks that result of lookup_one_len_unlocked() is positive
     (and rejection of negatives). Again, insufficient barriers (we
     might end up with inconsistent observed values of ->d_inode and
     ->d_flags). Fixed by switching to a new primitive that does the
     checks itself and returns ERR_PTR(-ENOENT) instead of a negative
     dentry. That way we get rid of boilerplate converting negatives
     into ERR_PTR(-ENOENT) in the callers and have a single place to
     deal with the barrier-related mess - inside fs/namei.c rather than
     in every caller out there.

  The guts of pathname resolution *do* need to be careful - the race
  found by Ritesh is real, as well as several similar races.
  Fortunately, it turns out that we can take care of that with fairly
  local changes in there.

  The tree-wide audit had not been fun, and I hate the idea of repeating
  it. I think the right approach would be to annotate the places where
  we are _not_ guaranteed ->d_inode/->d_flags stability and have sparse
  catch regressions. But I'm still not sure what would be the least
  invasive way of doing that and it's clearly the next cycle fodder"

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs/namei.c: fix missing barriers when checking positivity
  fix dget_parent() fastpath race
  new helper: lookup_positive_unlocked()
  fs/namei.c: pull positivity check into follow_managed()
2019-12-06 09:06:58 -08:00
Al Viro
2fa6b1e01a fs/namei.c: fix missing barriers when checking positivity
Pinned negative dentries can, generally, be made positive
by another thread.  Conditions that prevent that are
	* ->d_lock on dentry in question
	* parent directory held at least shared
	* nobody else could have observed the address of dentry
Most of the places working with those fall into one of those
categories; however, d_lookup() and friends need to be used
with some care.  Fortunately, there's not a lot of call sites,
and with few exceptions all of those fall under one of the
cases above.

Exceptions are all in fs/namei.c - in lookup_fast(), lookup_dcache()
and mountpoint_last().  Another one is lookup_slow() - there
dcache lookup is done with parent held shared, but the result
is used after we'd drop the lock.  The same happens in do_last() -
the lookup (in lookup_one()) is done with parent locked, but
result is used after unlocking.

lookup_fast(), do_last() and mountpoint_last() flat-out reject
negatives.

Most of lookup_dcache() calls are made with parent locked at least
shared; the only exception is lookup_one_len_unlocked().  It might
return pinned negative, needs serious care from callers.  Fortunately,
almost nobody calls it directly anymore; all but two callers have
converted to lookup_positive_unlocked(), which rejects negatives.

lookup_slow() is called by the same lookup_one_len_unlocked() (see
above), mountpoint_last() and walk_component().  In those two negatives
are rejected.

In other words, there is a small set of places where we need to
check carefully if a pinned potentially negative dentry is, in
fact, positive.  After that check we want to be sure that both
->d_inode and type bits in ->d_flags are stable and observed.
The set consists of follow_managed() (where the rejection happens
for lookup_fast(), walk_component() and do_last()), last_mountpoint()
and lookup_positive_unlocked().

Solution:
	1) transition from negative to positive (in __d_set_inode_and_type())
stores ->d_inode, then uses smp_store_release() to set ->d_flags type bits.
	2) aforementioned 3 places in fs/namei.c fetch ->d_flags with
smp_load_acquire() and bugger off if it type bits say "negative".
That way anyone downstream of those checks has dentry know positive pinned,
with ->d_inode and type bits of ->d_flags stable and observed.

I considered splitting off d_lookup_positive(), so that the checks could
be done right there, under ->d_lock.  However, that leads to massive
duplication of rather subtle code in fs/namei.c and fs/dcache.c.  It's
worse than it might seem, thanks to autofs ->d_manage() getting involved ;-/
No matter what, autofs_d_manage()/autofs_d_automount() must live with
the possibility of pinned negative dentry passed their way, becoming
positive under them - that's the intended behaviour when lookup comes
in the middle of automount in progress, so we can't keep them out of
the area that has to deal with those, more's the pity...

Reported-by: Ritesh Harjani <riteshh@linux.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-11-15 13:49:04 -05:00
Al Viro
6c2d4798a8 new helper: lookup_positive_unlocked()
Most of the callers of lookup_one_len_unlocked() treat negatives are
ERR_PTR(-ENOENT).  Provide a helper that would do just that.  Note
that a pinned positive dentry remains positive - it's ->d_inode is
stable, etc.; a pinned _negative_ dentry can become positive at any
point as long as you are not holding its parent at least shared.
So using lookup_one_len_unlocked() needs to be careful;
lookup_positive_unlocked() is safer and that's what the callers
end up open-coding anyway.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-11-15 13:49:04 -05:00
Al Viro
d41efb522e fs/namei.c: pull positivity check into follow_managed()
There are 4 callers; two proceed to check if result is positive and
fail with ENOENT if it isn't; one (in handle_lookup_down()) is
guaranteed to yield positive and one (in lookup_fast()) is _preceded_
by positivity check.

However, follow_managed() on a negative dentry is a (fairly cheap)
no-op on anything other than autofs.  And negative autofs dentries
are never hashed, so lookup_fast() is not going to run into one
of those.  Moreover, successful follow_managed() on a _positive_
dentry never yields a negative one (and we significantly rely upon
that in callers of lookup_fast()).

In other words, we can easily transpose the positivity check and
the call of follow_managed() in lookup_fast().  And that allows
to fold the positivity check *into* follow_managed(), simplifying
life for the code downstream of its calls.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-11-15 13:49:04 -05:00
Kees Cook
245d73698e audit: Report suspicious O_CREAT usage
This renames the very specific audit_log_link_denied() to
audit_log_path_denied() and adds the AUDIT_* type as an argument. This
allows for the creation of the new AUDIT_ANOM_CREAT that can be used to
report the fifo/regular file creation restrictions that were introduced
in commit 30aba6656f ("namei: allow restricted O_CREAT of FIFOs and
regular files").

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-10-03 13:59:29 -04:00
Al Viro
84a2bd3940 fs/namei.c: keep track of nd->root refcount status
The rules for nd->root are messy:
	* if we have LOOKUP_ROOT, it doesn't contribute to refcounts
	* if we have LOOKUP_RCU, it doesn't contribute to refcounts
	* if nd->root.mnt is NULL, it doesn't contribute to refcounts
	* otherwise it does contribute

terminate_walk() needs to drop the references if they are contributing.
So everything else should be careful not to confuse it, leading to
rather convoluted code.

It's easier to keep track of whether we'd grabbed the reference(s)
explicitly.  Use a new flag for that.  Don't bother with zeroing
nd->root.mnt on unlazy failures and in terminate_walk - it's not
needed anymore (terminate_walk() won't care and the next path_init()
will zero nd->root in !LOOKUP_ROOT case anyway).

Resulting rules for nd->root refcounts are much simpler: they are
contributing iff LOOKUP_ROOT_GRABBED is set in nd->flags.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-09-03 09:30:45 -04:00
Al Viro
ee594bfff3 fs/namei.c: new helper - legitimize_root()
identical logics in unlazy_walk() and unlazy_child()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-08-30 21:30:13 -04:00
Al Viro
c9b07eab0c audit_inode(): switch to passing AUDIT_INODE_...
don't bother with remapping LOOKUP_... values - all callers pass
constants and we can just as well pass the right ones from the
very beginning.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-07-21 18:24:46 -04:00
Al Viro
39145f5f0c filename_mountpoint(): make LOOKUP_NO_EVAL unconditional there
user_path_mountpoint_at() always gets it and the reasons to have it
there (i.e. in umount(2)) apply to kern_path_mountpoint() callers
as well.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-07-21 18:24:45 -04:00
Al Viro
ff0ebee239 filename_lookup(): audit_inode() argument is always 0
We hadn't been passing LOOKUP_PARENT in flags to that thing
since filename_parentat() had been split off back in 2015.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-07-21 18:24:44 -04:00
Amir Goldstein
116b9731ad fsnotify: add empty fsnotify_{unlink,rmdir}() hooks
We would like to move fsnotify_nameremove() calls from d_delete()
into a higher layer where the hook makes more sense and so we can
consider every d_delete() call site individually.

Start by creating empty hook fsnotify_{unlink,rmdir}() and place
them in the proper VFS call sites.  After all d_delete() call sites
will be converted to use the new hook, the new hook will generate the
delete events and fsnotify_nameremove() hook will be removed.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-06-20 14:44:55 +02:00
Linus Torvalds
a9fbcd6728 Clean up fscrypt's dcache revalidation support, and other
miscellaneous cleanups.
 -----BEGIN PGP SIGNATURE-----
 
 iQEzBAABCAAdFiEEK2m5VNv+CHkogTfJ8vlZVpUNgaMFAlzSEfQACgkQ8vlZVpUN
 gaNKrQf+O4JCCc8jqhpvUcNr8+DJNhWYpvRo7yDXoWbAyA6eZHV2fTRX5Vw6T8bW
 iQAj9ofkRnakOq6JvnaUyW8eAuRcqellF7HnwFwTxGOpZ1x3UPAV/roKutAhe8sT
 9dA0VxjugBAISbL2AMQKRPYNuzV07D9As6wZRlPuliFVLLnuPG5SseHRhdn3tm1n
 Jwyipu8P6BjomFtfHT25amISaWRx/uGpjTa1fmjwUxIC8EI6V9K6hKNCAUPsk/3g
 m8zEBpBKSmPK66sFPGxddPNGYAyyFluUboQxB7DuSCF7J3cULO8TxRZbsW/5jaio
 ZR8utWezuXnrI80vG/VtCMhqG3398Q==
 =0Bak
 -----END PGP SIGNATURE-----

Merge tag 'fscrypt_for_linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt

Pull fscrypt updates from Ted Ts'o:
 "Clean up fscrypt's dcache revalidation support, and other
  miscellaneous cleanups"

* tag 'fscrypt_for_linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt:
  fscrypt: cache decrypted symlink target in ->i_link
  vfs: use READ_ONCE() to access ->i_link
  fscrypt: fix race where ->lookup() marks plaintext dentry as ciphertext
  fscrypt: only set dentry_operations on ciphertext dentries
  fs, fscrypt: clear DCACHE_ENCRYPTED_NAME when unaliasing directory
  fscrypt: fix race allowing rename() and link() of ciphertext dentries
  fscrypt: clean up and improve dentry revalidation
  fscrypt: use READ_ONCE() to access ->i_crypt_info
  fscrypt: remove WARN_ON_ONCE() when decryption fails
  fscrypt: drop inode argument from fscrypt_get_ctx()
2019-05-07 21:28:04 -07:00
Al Viro
f4ec3a3d43 switch fsnotify_move() to passing const struct qstr * for old_name
note that in the second (RENAME_EXCHANGE) call of fsnotify_move() in
vfs_rename() the old_dentry->d_name is guaranteed to be unchanged
throughout the evaluation of fsnotify_move() (by the fact that the
parent directory is locked exclusive), so we don't need to fetch
old_dentry->d_name.name in the caller.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-04-26 13:22:05 -04:00
Al Viro
230c6402b1 ovl_lookup_real_one(): don't bother with strlen()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-04-26 13:13:33 -04:00
Eric Biggers
4c4f7c19b3 vfs: use READ_ONCE() to access ->i_link
Use 'READ_ONCE(inode->i_link)' to explicitly support filesystems caching
the symlink target in ->i_link later if it was unavailable at iget()
time, or wasn't easily available.  I'll be doing this in fscrypt, to
improve the performance of encrypted symlinks on ext4, f2fs, and ubifs.

->i_link will start NULL and may later be set to a non-NULL value by a
smp_store_release() or cmpxchg_release().  READ_ONCE() is needed on the
read side.  smp_load_acquire() is unnecessary because only a data
dependency barrier is required.  (Thanks to Al for pointing this out.)

Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-04-17 12:43:14 -04:00
Linus Torvalds
7b47a9e7c8 Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs mount infrastructure updates from Al Viro:
 "The rest of core infrastructure; no new syscalls in that pile, but the
  old parts are switched to new infrastructure. At that point
  conversions of individual filesystems can happen independently; some
  are done here (afs, cgroup, procfs, etc.), there's also a large series
  outside of that pile dealing with NFS (quite a bit of option-parsing
  stuff is getting used there - it's one of the most convoluted
  filesystems in terms of mount-related logics), but NFS bits are the
  next cycle fodder.

  It got seriously simplified since the last cycle; documentation is
  probably the weakest bit at the moment - I considered dropping the
  commit introducing Documentation/filesystems/mount_api.txt (cutting
  the size increase by quarter ;-), but decided that it would be better
  to fix it up after -rc1 instead.

  That pile allows to do followup work in independent branches, which
  should make life much easier for the next cycle. fs/super.c size
  increase is unpleasant; there's a followup series that allows to
  shrink it considerably, but I decided to leave that until the next
  cycle"

* 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (41 commits)
  afs: Use fs_context to pass parameters over automount
  afs: Add fs_context support
  vfs: Add some logging to the core users of the fs_context log
  vfs: Implement logging through fs_context
  vfs: Provide documentation for new mount API
  vfs: Remove kern_mount_data()
  hugetlbfs: Convert to fs_context
  cpuset: Use fs_context
  kernfs, sysfs, cgroup, intel_rdt: Support fs_context
  cgroup: store a reference to cgroup_ns into cgroup_fs_context
  cgroup1_get_tree(): separate "get cgroup_root to use" into a separate helper
  cgroup_do_mount(): massage calling conventions
  cgroup: stash cgroup_root reference into cgroup_fs_context
  cgroup2: switch to option-by-option parsing
  cgroup1: switch to option-by-option parsing
  cgroup: take options parsing into ->parse_monolithic()
  cgroup: fold cgroup1_mount() into cgroup1_get_tree()
  cgroup: start switching to fs_context
  ipc: Convert mqueue fs to fs_context
  proc: Add fs_context support to procfs
  ...
2019-03-12 14:08:19 -07:00
Linus Torvalds
c3665a6be5 Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull integrity updates from James Morris:
 "Mimi Zohar says:

   'Linux 5.0 introduced the platform keyring to allow verifying the IMA
    kexec kernel image signature using the pre-boot keys. This pull
    request similarly makes keys on the platform keyring accessible for
    verifying the PE kernel image signature.

    Also included in this pull request is a new IMA hook that tags tmp
    files, in policy, indicating the file hash needs to be calculated.
    The remaining patches are cleanup'"

* 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  evm: Use defined constant for UUID representation
  ima: define ima_post_create_tmpfile() hook and add missing call
  evm: remove set but not used variable 'xattr'
  encrypted-keys: fix Opt_err/Opt_error = -1
  kexec, KEYS: Make use of platform keyring for signature verify
  integrity, KEYS: add a reference to platform keyring
2019-03-10 17:32:04 -07:00
Linus Torvalds
b5dd0c658c Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton:

 - some of the rest of MM

 - various misc things

 - dynamic-debug updates

 - checkpatch

 - some epoll speedups

 - autofs

 - rapidio

 - lib/, lib/lzo/ updates

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (83 commits)
  samples/mic/mpssd/mpssd.h: remove duplicate header
  kernel/fork.c: remove duplicated include
  include/linux/relay.h: fix percpu annotation in struct rchan
  arch/nios2/mm/fault.c: remove duplicate include
  unicore32: stop printing the virtual memory layout
  MAINTAINERS: fix GTA02 entry and mark as orphan
  mm: create the new vm_fault_t type
  arm, s390, unicore32: remove oneliner wrappers for memblock_alloc()
  arch: simplify several early memory allocations
  openrisc: simplify pte_alloc_one_kernel()
  sh: prefer memblock APIs returning virtual address
  microblaze: prefer memblock API returning virtual address
  powerpc: prefer memblock APIs returning virtual address
  lib/lzo: separate lzo-rle from lzo
  lib/lzo: implement run-length encoding
  lib/lzo: fast 8-byte copy on arm64
  lib/lzo: 64-bit CTZ on arm64
  lib/lzo: tidy-up ifdefs
  ipc/sem.c: replace kvmalloc/memset with kvzalloc and use struct_size
  ipc: annotate implicit fall through
  ...
2019-03-07 19:25:37 -08:00
Rasmus Villemoes
f1fffbd447 linux/fs.h: move member alignment check next to definition of struct filename
Instead of doing this compile-time check in some slightly arbitrary user
of struct filename, put it next to the definition.

Link: http://lkml.kernel.org/r/20190208203015.29702-3-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-07 18:31:59 -08:00
David Howells
31d921c7fb vfs: Add configuration parser helpers
Because the new API passes in key,value parameters, match_token() cannot be
used with it.  Instead, provide three new helpers to aid with parsing:

 (1) fs_parse().  This takes a parameter and a simple static description of
     all the parameters and maps the key name to an ID.  It returns 1 on a
     match, 0 on no match if unknowns should be ignored and some other
     negative error code on a parse error.

     The parameter description includes a list of key names to IDs, desired
     parameter types and a list of enumeration name -> ID mappings.

     [!] Note that for the moment I've required that the key->ID mapping
     array is expected to be sorted and unterminated.  The size of the
     array is noted in the fsconfig_parser struct.  This allows me to use
     bsearch(), but I'm not sure any performance gain is worth the hassle
     of requiring people to keep the array sorted.

     The parameter type array is sized according to the number of parameter
     IDs and is indexed directly.  The optional enum mapping array is an
     unterminated, unsorted list and the size goes into the fsconfig_parser
     struct.

     The function can do some additional things:

	(a) If it's not ambiguous and no value is given, the prefix "no" on
	    a key name is permitted to indicate that the parameter should
	    be considered negatory.

	(b) If the desired type is a single simple integer, it will perform
	    an appropriate conversion and store the result in a union in
	    the parse result.

	(c) If the desired type is an enumeration, {key ID, name} will be
	    looked up in the enumeration list and the matching value will
	    be stored in the parse result union.

	(d) Optionally generate an error if the key is unrecognised.

     This is called something like:

	enum rdt_param {
		Opt_cdp,
		Opt_cdpl2,
		Opt_mba_mpbs,
		nr__rdt_params
	};

	const struct fs_parameter_spec rdt_param_specs[nr__rdt_params] = {
		[Opt_cdp]	= { fs_param_is_bool },
		[Opt_cdpl2]	= { fs_param_is_bool },
		[Opt_mba_mpbs]	= { fs_param_is_bool },
	};

	const const char *const rdt_param_keys[nr__rdt_params] = {
		[Opt_cdp]	= "cdp",
		[Opt_cdpl2]	= "cdpl2",
		[Opt_mba_mpbs]	= "mba_mbps",
	};

	const struct fs_parameter_description rdt_parser = {
		.name		= "rdt",
		.nr_params	= nr__rdt_params,
		.keys		= rdt_param_keys,
		.specs		= rdt_param_specs,
		.no_source	= true,
	};

	int rdt_parse_param(struct fs_context *fc,
			    struct fs_parameter *param)
	{
		struct fs_parse_result parse;
		struct rdt_fs_context *ctx = rdt_fc2context(fc);
		int ret;

		ret = fs_parse(fc, &rdt_parser, param, &parse);
		if (ret < 0)
			return ret;

		switch (parse.key) {
		case Opt_cdp:
			ctx->enable_cdpl3 = true;
			return 0;
		case Opt_cdpl2:
			ctx->enable_cdpl2 = true;
			return 0;
		case Opt_mba_mpbs:
			ctx->enable_mba_mbps = true;
			return 0;
		}

		return -EINVAL;
	}

 (2) fs_lookup_param().  This takes a { dirfd, path, LOOKUP_EMPTY? } or
     string value and performs an appropriate path lookup to convert it
     into a path object, which it will then return.

     If the desired type was a blockdev, the type of the looked up inode
     will be checked to make sure it is one.

     This can be used like:

	enum foo_param {
		Opt_source,
		nr__foo_params
	};

	const struct fs_parameter_spec foo_param_specs[nr__foo_params] = {
		[Opt_source]	= { fs_param_is_blockdev },
	};

	const char *char foo_param_keys[nr__foo_params] = {
		[Opt_source]	= "source",
	};

	const struct constant_table foo_param_alt_keys[] = {
		{ "device",	Opt_source },
	};

	const struct fs_parameter_description foo_parser = {
		.name		= "foo",
		.nr_params	= nr__foo_params,
		.nr_alt_keys	= ARRAY_SIZE(foo_param_alt_keys),
		.keys		= foo_param_keys,
		.alt_keys	= foo_param_alt_keys,
		.specs		= foo_param_specs,
	};

	int foo_parse_param(struct fs_context *fc,
			    struct fs_parameter *param)
	{
		struct fs_parse_result parse;
		struct foo_fs_context *ctx = foo_fc2context(fc);
		int ret;

		ret = fs_parse(fc, &foo_parser, param, &parse);
		if (ret < 0)
			return ret;

		switch (parse.key) {
		case Opt_source:
			return fs_lookup_param(fc, &foo_parser, param,
					       &parse, &ctx->source);
		default:
			return -EINVAL;
		}
	}

 (3) lookup_constant().  This takes a table of named constants and looks up
     the given name within it.  The table is expected to be sorted such
     that bsearch() be used upon it.

     Possibly I should require the table be terminated and just use a
     for-loop to scan it instead of using bsearch() to reduce hassle.

     Tables look something like:

	static const struct constant_table bool_names[] = {
		{ "0",		false },
		{ "1",		true },
		{ "false",	false },
		{ "no",		false },
		{ "true",	true },
		{ "yes",	true },
	};

     and a lookup is done with something like:

	b = lookup_constant(bool_names, param->string, -1);

Additionally, optional validation routines for the parameter description
are provided that can be enabled at compile time.  A later patch will
invoke these when a filesystem is registered.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-02-28 03:28:53 -05:00
Mimi Zohar
fdb2410f77 ima: define ima_post_create_tmpfile() hook and add missing call
If tmpfiles can be made persistent, then newly created tmpfiles need to
be treated like any other new files in policy.

This patch indicates which newly created tmpfiles are in policy, causing
the file hash to be calculated on __fput().

Reported-by: Ignaz Forster <ignaz.forster@gmx.de>
[rgoldwyn@suse.com: Call ima_post_create_tmpfile() in vfs_tmpfile() as
opposed to do_tmpfile(). This will help the case for overlayfs where
copy_up is denied while overwriting a file.]
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2019-02-04 17:36:01 -05:00
Richard Guy Briggs
57d4657716 audit: ignore fcaps on umount
Don't fetch fcaps when umount2 is called to avoid a process hang while
it waits for the missing resource to (possibly never) re-appear.

Note the comment above user_path_mountpoint_at():
 * A umount is a special case for path walking. We're not actually interested
 * in the inode in this situation, and ESTALE errors can be a problem.  We
 * simply want track down the dentry and vfsmount attached at the mountpoint
 * and avoid revalidating the last component.

This can happen on ceph, cifs, 9p, lustre, fuse (gluster) or NFS.

Please see the github issue tracker
https://github.com/linux-audit/audit-kernel/issues/100

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: merge fuzz in audit_log_fcaps()]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-01-30 20:51:47 -05:00
Christian Brauner
94f82008ce Revert "vfs: Allow userns root to call mknod on owned filesystems."
This reverts commit 55956b59df.

commit 55956b59df ("vfs: Allow userns root to call mknod on owned filesystems.")
enabled mknod() in user namespaces for userns root if CAP_MKNOD is
available. However, these device nodes are useless since any filesystem
mounted from a non-initial user namespace will set the SB_I_NODEV flag on
the filesystem. Now, when a device node s created in a non-initial user
namespace a call to open() on said device node will fail due to:

bool may_open_dev(const struct path *path)
{
        return !(path->mnt->mnt_flags & MNT_NODEV) &&
                !(path->mnt->mnt_sb->s_iflags & SB_I_NODEV);
}

The problem with this is that as of the aforementioned commit mknod()
creates partially functional device nodes in non-initial user namespaces.
In particular, it has the consequence that as of the aforementioned commit
open() will be more privileged with respect to device nodes than mknod().
Before it was the other way around. Specifically, if mknod() succeeded
then it was transparent for any userspace application that a fatal error
must have occured when open() failed.

All of this breaks multiple userspace workloads and a widespread assumption
about how to handle mknod(). Basically, all container runtimes and systemd
live by the slogan "ask for forgiveness not permission" when running user
namespace workloads. For mknod() the assumption is that if the syscall
succeeds the device nodes are useable irrespective of whether it succeeds
in a non-initial user namespace or not. This logic was chosen explicitly
to allow for the glorious day when mknod() will actually be able to create
fully functional device nodes in user namespaces.
A specific problem people are already running into when running 4.18 rc
kernels are failing systemd services. For any distro that is run in a
container systemd services started with the PrivateDevices= property set
will fail to start since the device nodes in question cannot be
opened (cf. the arguments in [1]).

Full disclosure, Seth made the very sound argument that it is already
possible to end up with partially functional device nodes. Any filesystem
mounted with MS_NODEV set will allow mknod() to succeed but will not allow
open() to succeed. The difference to the case here is that the MS_NODEV
case is transparent to userspace since it is an explicitly set mount option
while the SB_I_NODEV case is an implicit property enforced by the kernel
and hence opaque to userspace.

[1]: https://github.com/systemd/systemd/pull/9483

Signed-off-by: Christian Brauner <christian@brauner.io>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Seth Forshee <seth.forshee@canonical.com>
Cc: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-22 14:18:34 -08:00
Salvatore Mesoraca
30aba6656f namei: allow restricted O_CREAT of FIFOs and regular files
Disallows open of FIFOs or regular files not owned by the user in world
writable sticky directories, unless the owner is the same as that of the
directory or the file is opened without the O_CREAT flag.  The purpose
is to make data spoofing attacks harder.  This protection can be turned
on and off separately for FIFOs and regular files via sysctl, just like
the symlinks/hardlinks protection.  This patch is based on Openwall's
"HARDEN_FIFO" feature by Solar Designer.

This is a brief list of old vulnerabilities that could have been prevented
by this feature, some of them even allow for privilege escalation:

CVE-2000-1134
CVE-2007-3852
CVE-2008-0525
CVE-2009-0416
CVE-2011-4834
CVE-2015-1838
CVE-2015-7442
CVE-2016-7489

This list is not meant to be complete.  It's difficult to track down all
vulnerabilities of this kind because they were often reported without any
mention of this particular attack vector.  In fact, before
hardlinks/symlinks restrictions, fifos/regular files weren't the favorite
vehicle to exploit them.

[s.mesoraca16@gmail.com: fix bug reported by Dan Carpenter]
  Link: https://lkml.kernel.org/r/20180426081456.GA7060@mwanda
  Link: http://lkml.kernel.org/r/1524829819-11275-1-git-send-email-s.mesoraca16@gmail.com
[keescook@chromium.org: drop pr_warn_ratelimited() in favor of audit changes in the future]
[keescook@chromium.org: adjust commit subjet]
Link: http://lkml.kernel.org/r/20180416175918.GA13494@beast
Signed-off-by: Salvatore Mesoraca <s.mesoraca16@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Suggested-by: Solar Designer <solar@openwall.com>
Suggested-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-23 18:48:43 -07:00
Linus Torvalds
d9a185f8b4 overlayfs update for 4.19
This contains two new features:
 
  1) Stack file operations: this allows removal of several hacks from the
     VFS, proper interaction of read-only open files with copy-up,
     possibility to implement fs modifying ioctls properly, and others.
 
  2) Metadata only copy-up: when file is on lower layer and only metadata is
     modified (except size) then only copy up the metadata and continue to
     use the data from the lower file.
 -----BEGIN PGP SIGNATURE-----
 
 iHUEABYIAB0WIQSQHSd0lITzzeNWNm3h3BK/laaZPAUCW3srhAAKCRDh3BK/laaZ
 PC6tAQCP+KklcN+TvNp502f+O/kATahSpgnun4NY1/p4I8JV+AEAzdlkTN3+MiAO
 fn9brN6mBK7h59DO3hqedPLJy2vrgwg=
 =QDXH
 -----END PGP SIGNATURE-----

Merge tag 'ovl-update-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull overlayfs updates from Miklos Szeredi:
 "This contains two new features:

   - Stack file operations: this allows removal of several hacks from
     the VFS, proper interaction of read-only open files with copy-up,
     possibility to implement fs modifying ioctls properly, and others.

   - Metadata only copy-up: when file is on lower layer and only
     metadata is modified (except size) then only copy up the metadata
     and continue to use the data from the lower file"

* tag 'ovl-update-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (66 commits)
  ovl: Enable metadata only feature
  ovl: Do not do metacopy only for ioctl modifying file attr
  ovl: Do not do metadata only copy-up for truncate operation
  ovl: add helper to force data copy-up
  ovl: Check redirect on index as well
  ovl: Set redirect on upper inode when it is linked
  ovl: Set redirect on metacopy files upon rename
  ovl: Do not set dentry type ORIGIN for broken hardlinks
  ovl: Add an inode flag OVL_CONST_INO
  ovl: Treat metacopy dentries as type OVL_PATH_MERGE
  ovl: Check redirects for metacopy files
  ovl: Move some dir related ovl_lookup_single() code in else block
  ovl: Do not expose metacopy only dentry from d_real()
  ovl: Open file with data except for the case of fsync
  ovl: Add helper ovl_inode_realdata()
  ovl: Store lower data inode in ovl_inode
  ovl: Fix ovl_getattr() to get number of blocks from lower
  ovl: Add helper ovl_dentry_lowerdata() to get lower data dentry
  ovl: Copy up meta inode data from lowest data inode
  ovl: Modify ovl_lookup() and friends to lookup metacopy dentry
  ...
2018-08-21 18:19:09 -07:00
Linus Torvalds
4591343e35 Merge branches 'work.misc' and 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc vfs updates from Al Viro:
 "Misc cleanups from various folks all over the place

  I expected more fs/dcache.c cleanups this cycle, so that went into a
  separate branch. Said cleanups have missed the window, so in the
  hindsight it could've gone into work.misc instead. Decided not to
  cherry-pick, thus the 'work.dcache' branch"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: dcache: Use true and false for boolean values
  fold generic_readlink() into its only caller
  fs: shave 8 bytes off of struct inode
  fs: Add more kernel-doc to the produced documentation
  fs: Fix attr.c kernel-doc
  removed extra extern file_fdatawait_range

* 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  kill dentry_update_name_case()
2018-08-13 21:28:25 -07:00
Al Viro
f2df5da662 fold generic_readlink() into its only caller
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-19 17:35:51 -04:00
Miklos Szeredi
c671854346 Revert "vfs: update ovl inode before relatime check"
This reverts commit 598e3c8f72.

Overlayfs no longer relies on the vfs correct atime handling.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-07-18 15:44:43 +02:00
Al Viro
5f336e722c few more cleanups of link_path_walk() callers
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:31 -04:00
Al Viro
9b5858e99a allow link_path_walk() to take ERR_PTR()
There is a check for IS_ERR(name) immediately upstream of each call
of link_path_walk(name, nd), with positives treated as if link_path_walk()
failed with PTR_ERR(name).  Taking that check into link_path_walk() itself
simplifies things nicely.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:30 -04:00
Al Viro
edc2b1da77 make path_init() unconditionally paired with terminate_walk()
including the failure exits

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:30 -04:00
Al Viro
00a07c1591 switch atomic_open() and lookup_open() to returning 0 in all success cases
caller can tell "opened" from "open it yourself" by looking at ->f_mode.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:22 -04:00
Al Viro
64e1ac4d46 ->atomic_open(): return 0 in all success cases
FMODE_OPENED can be used to distingusish "successful open" from the
"called finish_no_open(), do it yourself" cases.  Since finish_no_open()
has been adjusted, no changes in the instances were actually needed.
The caller has been adjusted.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:21 -04:00
Al Viro
3ec2eef116 get rid of 'opened' in path_openat() and the helpers downstream
unused now

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:21 -04:00
Al Viro
44907d7900 get rid of 'opened' argument of ->atomic_open() - part 3
now it can be done...

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:20 -04:00
Al Viro
be12af3ef5 getting rid of 'opened' argument of ->atomic_open() - part 1
'opened' argument of finish_open() is unused.  Kill it.

Signed-off-by Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:19 -04:00
Al Viro
6035a27b25 IMA: don't propagate opened through the entire thing
just check ->f_mode in ima_appraise_measurement()

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:19 -04:00
Al Viro
73a09dd943 introduce FMODE_CREATED and switch to it
Parallel to FILE_CREATED, goes into ->f_mode instead of *opened.
NFS is a bit of a wart here - it doesn't have file at the point
where FILE_CREATED used to be set, so we need to propagate it
there (for now).  IMA is another one (here and everywhere)...

Note that this needs do_dentry_open() to leave old bits in ->f_mode
alone - we want it to preserve FMODE_CREATED if it had been already
set (no other bit can be there).

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:18 -04:00
Al Viro
aad888f828 switch all remaining checks for FILE_OPENED to FMODE_OPENED
... and don't bother with setting FILE_OPENED at all.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:18 -04:00
Al Viro
69527c554f now we can fold open_check_o_direct() into do_dentry_open()
These checks are better off in do_dentry_open(); the reason we couldn't
put them there used to be that callers couldn't tell what kind of cleanup
would do_dentry_open() failure call for.  Now that we have FMODE_OPENED,
cleanup is the same in all cases - it's simply fput().  So let's fold
that into do_dentry_open(), as Christoph's patch tried to.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:17 -04:00
Al Viro
7c1c01ec20 lift fput() on late failures into path_openat()
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:17 -04:00
Al Viro
4d27f3266f fold put_filp() into fput()
Just check FMODE_OPENED in __fput() and be done with that...

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:16 -04:00
Al Viro
ae2bb293a3 get rid of cred argument of vfs_open() and do_dentry_open()
always equal to ->f_cred

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:14 -04:00
Al Viro
ea73ea7279 pass ->f_flags value to alloc_empty_file()
... and have it set the f_flags-derived part of ->f_mode.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:13 -04:00
Al Viro
6de37b6dc0 pass creds to get_empty_filp(), make sure dentry_open() passes the right creds
... and rename get_empty_filp() to alloc_empty_file().

dentry_open() gets creds as argument, but the only thing that sees those is
security_file_open() - file->f_cred still ends up with current_cred().  For
almost all callers it's the same thing, but there are several broken cases.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:13 -04:00
Linus Torvalds
35773c9381 Merge branch 'afs-proc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull AFS updates from Al Viro:
 "Assorted AFS stuff - ended up in vfs.git since most of that consists
  of David's AFS-related followups to Christoph's procfs series"

* 'afs-proc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  afs: Optimise callback breaking by not repeating volume lookup
  afs: Display manually added cells in dynamic root mount
  afs: Enable IPv6 DNS lookups
  afs: Show all of a server's addresses in /proc/fs/afs/servers
  afs: Handle CONFIG_PROC_FS=n
  proc: Make inline name size calculation automatic
  afs: Implement network namespacing
  afs: Mark afs_net::ws_cell as __rcu and set using rcu functions
  afs: Fix a Sparse warning in xdr_decode_AFSFetchStatus()
  proc: Add a way to make network proc files writable
  afs: Rearrange fs/afs/proc.c to remove remaining predeclarations.
  afs: Rearrange fs/afs/proc.c to move the show routines up
  afs: Rearrange fs/afs/proc.c by moving fops and open functions down
  afs: Move /proc management functions to the end of the file
2018-06-16 16:32:04 +09:00
David Howells
0da0b7fd73 afs: Display manually added cells in dynamic root mount
Alter the dynroot mount so that cells created by manipulation of
/proc/fs/afs/cells and /proc/fs/afs/rootcell and by specification of a root
cell as a module parameter will cause directories for those cells to be
created in the dynamic root superblock for the network namespace[*].

To this end:

 (1) Only one dynamic root superblock is now created per network namespace
     and this is shared between all attempts to mount it.  This makes it
     easier to find the superblock to modify.

 (2) When a dynamic root superblock is created, the list of cells is walked
     and directories created for each cell already defined.

 (3) When a new cell is added, if a dynamic root superblock exists, a
     directory is created for it.

 (4) When a cell is destroyed, the directory is removed.

 (5) These directories are created by calling lookup_one_len() on the root
     dir which automatically creates them if they don't exist.

[*] Inasmuch as network namespaces are currently supported here.

Signed-off-by: David Howells <dhowells@redhat.com>
2018-06-15 15:27:09 +01:00
Kees Cook
6da2ec5605 treewide: kmalloc() -> kmalloc_array()
The kmalloc() function has a 2-factor argument form, kmalloc_array(). This
patch replaces cases of:

        kmalloc(a * b, gfp)

with:
        kmalloc_array(a * b, gfp)

as well as handling cases of:

        kmalloc(a * b * c, gfp)

with:

        kmalloc(array3_size(a, b, c), gfp)

as it's slightly less ugly than:

        kmalloc_array(array_size(a, b), c, gfp)

This does, however, attempt to ignore constant size factors like:

        kmalloc(4 * 1024, gfp)

though any constants defined via macros get caught up in the conversion.

Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.

The tools/ directory was manually excluded, since it has its own
implementation of kmalloc().

The Coccinelle script used for this was:

// Fix redundant parens around sizeof().
@@
type TYPE;
expression THING, E;
@@

(
  kmalloc(
-	(sizeof(TYPE)) * E
+	sizeof(TYPE) * E
  , ...)
|
  kmalloc(
-	(sizeof(THING)) * E
+	sizeof(THING) * E
  , ...)
)

// Drop single-byte sizes and redundant parens.
@@
expression COUNT;
typedef u8;
typedef __u8;
@@

(
  kmalloc(
-	sizeof(u8) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(__u8) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(char) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(unsigned char) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(u8) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(__u8) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(char) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(unsigned char) * COUNT
+	COUNT
  , ...)
)

// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@

(
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (COUNT_ID)
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * COUNT_ID
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (COUNT_CONST)
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * COUNT_CONST
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (COUNT_ID)
+	COUNT_ID, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * COUNT_ID
+	COUNT_ID, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (COUNT_CONST)
+	COUNT_CONST, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * COUNT_CONST
+	COUNT_CONST, sizeof(THING)
  , ...)
)

// 2-factor product, only identifiers.
@@
identifier SIZE, COUNT;
@@

- kmalloc
+ kmalloc_array
  (
-	SIZE * COUNT
+	COUNT, SIZE
  , ...)

// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@

(
  kmalloc(
-	sizeof(TYPE) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(THING) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
)

// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@

(
  kmalloc(
-	sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  kmalloc(
-	sizeof(THING1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(THING1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
)

// 3-factor product, only identifiers, with redundant parens removed.
@@
identifier STRIDE, SIZE, COUNT;
@@

(
  kmalloc(
-	(COUNT) * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
)

// Any remaining multi-factor products, first at least 3-factor products,
// when they're not all constants...
@@
expression E1, E2, E3;
constant C1, C2, C3;
@@

(
  kmalloc(C1 * C2 * C3, ...)
|
  kmalloc(
-	(E1) * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	(E1) * (E2) * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	(E1) * (E2) * (E3)
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	E1 * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
)

// And then all remaining 2 factors products when they're not all constants,
// keeping sizeof() as the second factor argument.
@@
expression THING, E1, E2;
type TYPE;
constant C1, C2, C3;
@@

(
  kmalloc(sizeof(THING) * C2, ...)
|
  kmalloc(sizeof(TYPE) * C2, ...)
|
  kmalloc(C1 * C2 * C3, ...)
|
  kmalloc(C1 * C2, ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (E2)
+	E2, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * E2
+	E2, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (E2)
+	E2, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * E2
+	E2, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	(E1) * E2
+	E1, E2
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	(E1) * (E2)
+	E1, E2
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	E1 * E2
+	E1, E2
  , ...)
)

Signed-off-by: Kees Cook <keescook@chromium.org>
2018-06-12 16:19:22 -07:00
Linus Torvalds
d8aed8415b Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull userns updates from Eric Biederman:
 "This is the last couple of vfs bits to enable root in a user namespace
  to mount and manipulate a filesystem with backing store (AKA not a
  virtual filesystem like proc, but a filesystem where the unprivileged
  user controls the content). The target filesystem for this work is
  fuse, and Miklos should be sending you the pull request for the fuse
  bits this merge window.

  The two key patches are "evm: Don't update hmacs in user ns mounts"
  and "vfs: Don't allow changing the link count of an inode with an
  invalid uid or gid". Those close small gaps in the vfs that would be a
  problem if an unprivileged fuse filesystem is mounted.

  The rest of the changes are things that are now safe to allow a root
  user in a user namespace to do with a filesystem they have mounted.
  The most interesting development is that remount is now safe"

* 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  fs: Allow CAP_SYS_ADMIN in s_user_ns to freeze and thaw filesystems
  capabilities: Allow privileged user in s_user_ns to set security.* xattrs
  fs: Allow superblock owner to access do_remount_sb()
  fs: Allow superblock owner to replace invalid owners of inodes
  vfs: Allow userns root to call mknod on owned filesystems.
  vfs: Don't allow changing the link count of an inode with an invalid uid or gid
  evm: Don't update hmacs in user ns mounts
2018-06-04 15:21:19 -07:00
Linus Torvalds
f956d08a56 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc vfs updates from Al Viro:
 "Misc bits and pieces not fitting into anything more specific"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  vfs: delete unnecessary assignment in vfs_listxattr
  Documentation: filesystems: update filesystem locking documentation
  vfs: namei: use path_equal() in follow_dotdot()
  fs.h: fix outdated comment about file flags
  __inode_security_revalidate() never gets NULL opt_dentry
  make xattr_getsecurity() static
  vfat: simplify checks in vfat_lookup()
  get rid of dead code in d_find_alias()
  it's SB_BORN, not MS_BORN...
  msdos_rmdir(): kill BS comment
  remove rpc_rmdir()
  fs: avoid fdput() after failed fdget() in vfs_dedupe_file_range()
2018-06-04 10:14:28 -07:00
Linus Torvalds
9c50eafc32 Merge branch 'work.rmdir' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull rmdir update from Al Viro:
 "More shrink_dcache_parent()-related stuff - killing the main source of
  potentially contended calls of that on large subtrees"

* 'work.rmdir' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  rmdir(),rename(): do shrink_dcache_parent() only on success
2018-06-04 09:53:33 -07:00
Al Viro
af04fadcaa Revert "fs: fold open_check_o_direct into do_dentry_open"
This reverts commit cab64df194.

Having vfs_open() in some cases drop the reference to
struct file combined with

	error = vfs_open(path, f, cred);
	if (error) {
		put_filp(f);
		return ERR_PTR(error);
	}
	return f;

is flat-out wrong.  It used to be

		error = vfs_open(path, f, cred);
		if (!error) {
			/* from now on we need fput() to dispose of f */
			error = open_check_o_direct(f);
			if (error) {
				fput(f);
				f = ERR_PTR(error);
			}
		} else {
			put_filp(f);
			f = ERR_PTR(error);
		}

and sure, having that open_check_o_direct() boilerplate gotten rid of is
nice, but not that way...

Worse, another call chain (via finish_open()) is FUBAR now wrt
FILE_OPENED handling - in that case we get error returned, with file
already hit by fput() *AND* FILE_OPENED not set.  Guess what happens in
path_openat(), when it hits

	if (!(opened & FILE_OPENED)) {
		BUG_ON(!error);
		put_filp(file);
	}

The root cause of all that crap is that the callers of do_dentry_open()
have no way to tell which way did it fail; while that could be fixed up
(by passing something like int *opened to do_dentry_open() and have it
marked if we'd called ->open()), it's probably much too late in the
cycle to do so right now.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-03 10:58:23 -07:00
Al Viro
8767712f26 rmdir(),rename(): do shrink_dcache_parent() only on success
Once upon a time ->rmdir() instances used to check if victim inode
had more than one (in-core) reference and failed with -EBUSY if it
had.  The reason was race avoidance - emptiness check is worthless
if somebody could just go and create new objects in the victim
directory afterwards.

With introduction of dcache the checks had been replaced with
checking the refcount of dentry.  However, since a cached negative
lookup leaves a negative child dentry, such check had lead to false
positives - with empty foo/ doing stat foo/bar before rmdir foo
ended up with -EBUSY unless the negative dentry of foo/bar happened
to be evicted by the time of rmdir(2).  That had been fixed by
doing shrink_dcache_parent() just before the refcount check.

At the same time, ext2_rmdir() has grown a private solution that
eliminated those -EBUSY - it did something (setting ->i_size to 0)
which made any subsequent ext2_add_entry() fail.

Unfortunately, even with shrink_dcache_parent() the check had been
racy - after all, the victim itself could be found by dcache lookup
just after we'd checked its refcount.  That got fixed by a new
helper (dentry_unhash()) that did shrink_dcache_parent() and unhashed
the sucker if its refcount ended up equal to 1.  That got called before
->rmdir(), turning the checks in ->rmdir() instances into "if not
unhashed fail with -EBUSY".  Which reduced the boilerplate nicely, but
had an unpleasant side effect - now shrink_dcache_parent() had been
done before the emptiness checks, leading to easily triggerable calls
of shrink_dcache_parent() on arbitrary large subtrees, quite possibly
nested into each other.

Several years later the ext2-private trick had been generalized -
(in-core) inodes of dead directories are flagged and calls of
lookup, readdir and all directory-modifying methods were prevented
in so marked directories.  Remaining boilerplate in ->rmdir() instances
became redundant and some instances got rid of it.

In 2011 the call of dentry_unhash() got shifted into ->rmdir() instances
and then killed off in all of them.  That has lead to another problem,
though - in case of successful rmdir we *want* any (negative) child
dentries dropped and the victim itself made negative.  There's no point
keeping cached negative lookups in foo when we can get the negative
lookup of foo itself cached.  So shrink_dcache_parent() call had been
restored; unfortunately, it went into the place where dentry_unhash()
used to be, i.e. before the ->rmdir() call.  Note that we don't unhash
anymore, so any "is it busy" checks would be racy; fortunately, all of
them are gone.

We should've done that call right *after* successful ->rmdir().  That
reduces contention caused by tree-walking in shrink_dcache_parent()
and, especially, contention caused by evictions in two nested subtrees
going on in parallel.  The same goes for directory-overwriting rename() -
the story there had been parallel to that of rmdir().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-05-27 16:23:51 -04:00
Eric W. Biederman
55956b59df vfs: Allow userns root to call mknod on owned filesystems.
These filesystems already always set SB_I_NODEV so mknod will not be
useful for gaining control of any devices no matter their permissions.
This will allow overlayfs and applications like to fakeroot to use
device nodes to represent things on disk.

Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-05-24 11:56:43 -05:00
Eric W. Biederman
593d1ce854 vfs: Don't allow changing the link count of an inode with an invalid uid or gid
Changing the link count of an inode via unlink or link will cause a
write back of that inode.  If the uids or gids are invalid (aka not known
to the kernel) writing the inode back may change the uid or gid in the
filesystem.   To prevent possible filesystem and to avoid the need for
filesystem maintainers to worry about it don't allow operations on
inodes with an invalid uid or gid.

Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-05-24 11:56:18 -05:00
Danilo Krummrich
030c7e0bb7 vfs: namei: use path_equal() in follow_dotdot()
Use path_equal() to detect whether we're already in root.

Signed-off-by: Danilo Krummrich <danilokrummrich@dk-develop.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-05-17 22:19:39 -04:00
Linus Torvalds
fd3b36d275 Merge branch 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs namei updates from Al Viro:

 - make lookup_one_len() safe with parent locked only shared(incoming
   afs series wants that)

 - fix of getname_kernel() regression from 2015 (-stable fodder, that
   one).

* 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  getname_kernel() needs to make sure that ->name != ->iname in long case
  make lookup_one_len() safe to use with directory locked shared
  new helper: __lookup_slow()
  merge common parts of lookup_one_len{,_unlocked} into common helper
2018-04-09 12:48:05 -07:00
Al Viro
30ce4d1903 getname_kernel() needs to make sure that ->name != ->iname in long case
missed it in "kill struct filename.separate" several years ago.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-04-08 11:57:10 -04:00
Linus Torvalds
6ad11bdd57 audit/stable-4.17 PR 20180403
-----BEGIN PGP SIGNATURE-----
 
 iQJIBAABCAAyFiEEcQCq365ubpQNLgrWVeRaWujKfIoFAlrD6T4UHHBhdWxAcGF1
 bC1tb29yZS5jb20ACgkQVeRaWujKfIqGOg/9FPgs5cESBrocEOBAqqcmO3qjxaEy
 NKQWGTPppZwI5f5pOStL5GT3oU8jQp3IMjzUM2yIElFUg+RM5cwb0bLmhAMCJFCd
 vtrJmGDdQ0QEj5wqkprupaVEKENlSKaKePJq3NESFtcHs2cgfcIRsycj1LaOThNi
 fUcltiocBDS/jxurCgi2s4O2JTGEXfZaI0GojKjWDddL3N6QcD5aZgPQd/67T0Pt
 5dDgkXbGkd5pR97F+LovaTuLTaMXnUx5plMUd/LsueZbOxHjZL2O2E/h4aoXATMX
 zKdtG03wEebb65cQyczeTXRIBURIQCka0U0fHx7ZhS8vK2HVgr6oGfsJfyZhSp+l
 IIb/T1dSbgUURpMH0DiGs/pQrXO/9o7Rp7wIakycIHD0kcw503hbauqJEc6pwlx6
 /WQQTo6GKwHWW67OQ7AbIt4Gh9P/s96s6kEZGRH2NAjKY9xTZVM7+nnKL8hHk0xq
 uDN20AZuD5i9cZpVqw+MYdmeuHRuNPglY9S33MyaBbFeWl48voFxiabVpV3ENfLB
 Iyc5WzpxekJi9JLneEt6/r6XIissvHxsoIPL1lCYSAPIJQRmqg4sGHKAQ9o5NtFD
 MrRZSbBQVwt3+YFKixUcU+nvnhroJsQExejZoFmAdQl8f0TiihwYl8E4lSmy7ntr
 IzNm7li+y9VRJ54=
 =n1dk
 -----END PGP SIGNATURE-----

Merge tag 'audit-pr-20180403' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit

Pull audit updates from Paul Moore:
 "We didn't have anything to send for v4.16, but we're back with a
  little more than usual for v4.17.

  Eleven patches in total, most fall into the small fix category, but
  there are three non-trivial changes worth calling out:

   - the audit entry filter is being removed after deprecating it for
     quite a while (years of no one really using it because it turns out
     to be not very practical)

   - created our own version of "__mutex_owner()" because the locking
     folks were upset we were using theirs

   - improved our handling of kernel command line parameters to make
     them more forgiving

   - we fixed auditing of symlink operations

  Everything passes the audit-testsuite and as of a few minutes ago it
  merges well with your tree"

* tag 'audit-pr-20180403' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
  audit: add refused symlink to audit_names
  audit: remove path param from link denied function
  audit: link denied should not directly generate PATH record
  audit: make ANOM_LINK obey audit_enabled and audit_dummy_context
  audit: do not panic on invalid boot parameter
  audit: track the owner of the command mutex ourselves
  audit: return on memory error to avoid null pointer dereference
  audit: bail before bug check if audit disabled
  audit: deprecate the AUDIT_FILTER_ENTRY filter
  audit: session ID should not set arch quick field pointer
  audit: update bugtracker and source URIs
2018-04-06 15:01:25 -07:00
Al Viro
8613a209ff make lookup_one_len() safe to use with directory locked shared
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-04-06 16:45:33 -04:00
Al Viro
88d8331afb new helper: __lookup_slow()
lookup_slow() sans locking/unlocking the directory

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-04-06 16:43:47 -04:00
Al Viro
3c95f0dce8 merge common parts of lookup_one_len{,_unlocked} into common helper
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-04-06 16:33:40 -04:00
Linus Torvalds
9022ca6b11 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc vfs updates from Al Viro:
 "Assorted stuff, including Christoph's I_DIRTY patches"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: move I_DIRTY_INODE to fs.h
  ubifs: fix bogus __mark_inode_dirty(I_DIRTY_SYNC | I_DIRTY_DATASYNC) call
  ntfs: fix bogus __mark_inode_dirty(I_DIRTY_SYNC | I_DIRTY_DATASYNC) call
  gfs2: fix bogus __mark_inode_dirty(I_DIRTY_SYNC | I_DIRTY_DATASYNC) calls
  fs: fold open_check_o_direct into do_dentry_open
  vfs: Replace stray non-ASCII homoglyph characters with their ASCII equivalents
  vfs: make sure struct filename->iname is word-aligned
  get rid of pointless includes of fs_struct.h
  [poll] annotate SAA6588_CMD_POLL users
2018-04-06 11:07:08 -07:00
Linus Torvalds
2e08edc5c5 Merge branch 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs dcache updates from Al Viro:
 "Part of this is what the trylock loop elimination series has turned
  into, part making d_move() preserve the parent (and thus the path) of
  victim, plus some general cleanups"

* 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (22 commits)
  d_genocide: move export to definition
  fold dentry_lock_for_move() into its sole caller and clean it up
  make non-exchanging __d_move() copy ->d_parent rather than swap them
  oprofilefs: don't oops on allocation failure
  lustre: get rid of pointless casts to struct dentry *
  debugfs_lookup(): switch to lookup_one_len_unlocked()
  fold lookup_real() into __lookup_hash()
  take out orphan externs (empty_string/slash_string)
  split d_path() and friends into a separate file
  dcache.c: trim includes
  fs/dcache: Avoid a try_lock loop in shrink_dentry_list()
  get rid of trylock loop around dentry_kill()
  handle move to LRU in retain_dentry()
  dput(): consolidate the "do we need to retain it?" into an inlined helper
  split the slow part of lock_parent() off
  now lock_parent() can't run into killed dentry
  get rid of trylock loop in locking dentries on shrink list
  d_delete(): get rid of trylock loop
  fs/dcache: Move dentry_kill() below lock_parent()
  fs/dcache: Remove stale comment from dentry_kill()
  ...
2018-04-04 12:05:25 -07:00
Linus Torvalds
642e7fd233 Merge branch 'syscalls-next' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux
Pull removal of in-kernel calls to syscalls from Dominik Brodowski:
 "System calls are interaction points between userspace and the kernel.
  Therefore, system call functions such as sys_xyzzy() or
  compat_sys_xyzzy() should only be called from userspace via the
  syscall table, but not from elsewhere in the kernel.

  At least on 64-bit x86, it will likely be a hard requirement from
  v4.17 onwards to not call system call functions in the kernel: It is
  better to use use a different calling convention for system calls
  there, where struct pt_regs is decoded on-the-fly in a syscall wrapper
  which then hands processing over to the actual syscall function. This
  means that only those parameters which are actually needed for a
  specific syscall are passed on during syscall entry, instead of
  filling in six CPU registers with random user space content all the
  time (which may cause serious trouble down the call chain). Those
  x86-specific patches will be pushed through the x86 tree in the near
  future.

  Moreover, rules on how data may be accessed may differ between kernel
  data and user data. This is another reason why calling sys_xyzzy() is
  generally a bad idea, and -- at most -- acceptable in arch-specific
  code.

  This patchset removes all in-kernel calls to syscall functions in the
  kernel with the exception of arch/. On top of this, it cleans up the
  three places where many syscalls are referenced or prototyped, namely
  kernel/sys_ni.c, include/linux/syscalls.h and include/linux/compat.h"

* 'syscalls-next' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux: (109 commits)
  bpf: whitelist all syscalls for error injection
  kernel/sys_ni: remove {sys_,sys_compat} from cond_syscall definitions
  kernel/sys_ni: sort cond_syscall() entries
  syscalls/x86: auto-create compat_sys_*() prototypes
  syscalls: sort syscall prototypes in include/linux/compat.h
  net: remove compat_sys_*() prototypes from net/compat.h
  syscalls: sort syscall prototypes in include/linux/syscalls.h
  kexec: move sys_kexec_load() prototype to syscalls.h
  x86/sigreturn: use SYSCALL_DEFINE0
  x86: fix sys_sigreturn() return type to be long, not unsigned long
  x86/ioport: add ksys_ioperm() helper; remove in-kernel calls to sys_ioperm()
  mm: add ksys_readahead() helper; remove in-kernel calls to sys_readahead()
  mm: add ksys_mmap_pgoff() helper; remove in-kernel calls to sys_mmap_pgoff()
  mm: add ksys_fadvise64_64() helper; remove in-kernel call to sys_fadvise64_64()
  fs: add ksys_fallocate() wrapper; remove in-kernel calls to sys_fallocate()
  fs: add ksys_p{read,write}64() helpers; remove in-kernel calls to syscalls
  fs: add ksys_truncate() wrapper; remove in-kernel calls to sys_truncate()
  fs: add ksys_sync_file_range helper(); remove in-kernel calls to syscall
  kernel: add ksys_setsid() helper; remove in-kernel call to sys_setsid()
  kernel: add ksys_unshare() helper; remove in-kernel calls to sys_unshare()
  ...
2018-04-02 21:22:12 -07:00
Dominik Brodowski
46ea89eb65 fs: add do_linkat() helper and ksys_link() wrapper; remove in-kernel calls to syscall
Using the fs-internal do_linkat() helper allows us to get rid of
fs-internal calls to the sys_linkat() syscall.

Introducing the ksys_link() wrapper allows us to avoid the in-kernel
calls to sys_link() syscall. The ksys_ prefix denotes that this function
is meant as a drop-in replacement for the syscall. In particular, it uses
the same calling convention as sys_link().

In the near future, the only fs-external user of ksys_link() should be
converted to use vfs_link() instead.

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:15:57 +02:00
Dominik Brodowski
87c4e19262 fs: add do_mknodat() helper and ksys_mknod() wrapper; remove in-kernel calls to syscall
Using the fs-internal do_mknodat() helper allows us to get rid of
fs-internal calls to the sys_mknodat() syscall.

Introducing the ksys_mknod() wrapper allows us to avoid the in-kernel
calls to sys_mknod() syscall. The ksys_ prefix denotes that this function
is meant as a drop-in replacement for the syscall. In particular, it uses
the same calling convention as sys_mknod().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:15:56 +02:00
Dominik Brodowski
b724e846b4 fs: add do_symlinkat() helper and ksys_symlink() wrapper; remove in-kernel calls to syscall
Using the fs-internal do_symlinkat() helper allows us to get rid of
fs-internal calls to the sys_symlinkat() syscall.

Introducing the ksys_symlink() wrapper allows us to avoid the in-kernel
calls to the sys_symlink() syscall. The ksys_ prefix denotes that this
function is meant as a drop-in replacement for the syscall. In particular,
it uses the same calling convention as sys_symlink().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:15:55 +02:00
Dominik Brodowski
0101db7a30 fs: add do_mkdirat() helper and ksys_mkdir() wrapper; remove in-kernel calls to syscall
Using the fs-internal do_mkdirat() helper allows us to get rid of
fs-internal calls to the sys_mkdirat() syscall.

Introducing the ksys_mkdir() wrapper allows us to avoid the in-kernel calls
to the sys_mkdir() syscall. The ksys_ prefix denotes that this function is
meant as a drop-in replacement for the syscall. In particular, it uses the
same calling convention as sys_mkdir().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:15:54 +02:00
Dominik Brodowski
f459dffae1 fs: add ksys_rmdir() wrapper; remove in-kernel calls to sys_rmdir()
Using this wrapper allows us to avoid the in-kernel calls to the
sys_rmdir() syscall. The ksys_ prefix denotes that this function is meant
as a drop-in replacement for the syscall. In particular, it uses the same
calling convention as sys_rmdir().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:15:54 +02:00
Dominik Brodowski
ee81feb64e fs: add do_renameat2() helper; remove internal call to sys_renameat2()
Using this helper removes in-kernel calls to the sys_renameat2() syscall.

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:15:36 +02:00
Al Viro
a03ece5ff2 fold lookup_real() into __lookup_hash()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-03-29 15:07:47 -04:00
Christoph Hellwig
cab64df194 fs: fold open_check_o_direct into do_dentry_open
do_dentry_open is where we do the actual open of the file, so this is
where we should do our O_DIRECT sanity check to cover all potential
callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-03-28 01:39:01 -04:00
Richard Guy Briggs
ea841bafda audit: add refused symlink to audit_names
Audit link denied events for symlinks had duplicate PATH records rather
than just updating the existing PATH record.  Update the symlink's PATH
record with the current dentry and inode information.

See: https://github.com/linux-audit/audit-kernel/issues/21

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2018-03-21 11:31:03 -04:00
Richard Guy Briggs
94b9d9b7a1 audit: remove path param from link denied function
In commit 45b578fe4c
("audit: link denied should not directly generate PATH record")
the need for the struct path *link parameter was removed.
Remove the now useless struct path argument.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2018-03-21 11:17:41 -04:00
Rasmus Villemoes
1c94984396 vfs: make sure struct filename->iname is word-aligned
I noticed that offsetof(struct filename, iname) is actually 28 on 64
bit platforms, so we always pass an unaligned pointer to
strncpy_from_user. This is mostly a problem for those 64 bit platforms
without HAVE_EFFICIENT_UNALIGNED_ACCESS, but even on x86_64, unaligned
accesses carry a penalty.

A user-space microbenchmark doing nothing but strncpy_from_user from the
same (aligned) source string runs about 5% faster when the destination
is aligned. That number increases to 20% when the string is long
enough (~32 bytes) that we cross a cache line boundary - that's for
example the case for about half the files a "git status" in a kernel
tree ends up stat'ing.

This won't make any real-life workloads 5%, or even 1%, faster, but path
lookup is common enough that cutting even a few cycles should be
worthwhile. So ensure we always pass an aligned destination pointer to
strncpy_from_user. Instead of explicit padding, simply swap the refcnt
and aname members, as suggested by Al Viro.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-03-19 01:07:04 -04:00
Eric W. Biederman
95dd77580c fs: Teach path_connected to handle nfs filesystems with multiple roots.
On nfsv2 and nfsv3 the nfs server can export subsets of the same
filesystem and report the same filesystem identifier, so that the nfs
client can know they are the same filesystem.  The subsets can be from
disjoint directory trees.  The nfsv2 and nfsv3 filesystems provides no
way to find the common root of all directory trees exported form the
server with the same filesystem identifier.

The practical result is that in struct super s_root for nfs s_root is
not necessarily the root of the filesystem.  The nfs mount code sets
s_root to the root of the first subset of the nfs filesystem that the
kernel mounts.

This effects the dcache invalidation code in generic_shutdown_super
currently called shrunk_dcache_for_umount and that code for years
has gone through an additional list of dentries that might be dentry
trees that need to be freed to accomodate nfs.

When I wrote path_connected I did not realize nfs was so special, and
it's hueristic for avoiding calling is_subdir can fail.

The practical case where this fails is when there is a move of a
directory from the subtree exposed by one nfs mount to the subtree
exposed by another nfs mount.  This move can happen either locally or
remotely.  With the remote case requiring that the move directory be cached
before the move and that after the move someone walks the path
to where the move directory now exists and in so doing causes the
already cached directory to be moved in the dcache through the magic
of d_splice_alias.

If someone whose working directory is in the move directory or a
subdirectory and now starts calling .. from the initial mount of nfs
(where s_root == mnt_root), then path_connected as a heuristic will
not bother with the is_subdir check.  As s_root really is not the root
of the nfs filesystem this heuristic is wrong, and the path may
actually not be connected and path_connected can fail.

The is_subdir function might be cheap enough that we can call it
unconditionally.  Verifying that will take some benchmarking and
the result may not be the same on all kernels this fix needs
to be backported to.  So I am avoiding that for now.

Filesystems with snapshots such as nilfs and btrfs do something
similar.  But as the directory tree of the snapshots are disjoint
from one another and from the main directory tree rename won't move
things between them and this problem will not occur.

Cc: stable@vger.kernel.org
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Fixes: 397d425dc2 ("vfs: Test for and handle paths that are unreachable from their mnt_root")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-03-15 18:48:38 -04:00
Linus Torvalds
19e7b5f994 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc vfs updates from Al Viro:
 "All kinds of misc stuff, without any unifying topic, from various
  people.

  Neil's d_anon patch, several bugfixes, introduction of kvmalloc
  analogue of kmemdup_user(), extending bitfield.h to deal with
  fixed-endians, assorted cleanups all over the place..."

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (28 commits)
  alpha: osf_sys.c: use timespec64 where appropriate
  alpha: osf_sys.c: fix put_tv32 regression
  jffs2: Fix use-after-free bug in jffs2_iget()'s error handling path
  dcache: delete unused d_hash_mask
  dcache: subtract d_hash_shift from 32 in advance
  fs/buffer.c: fold init_buffer() into init_page_buffers()
  fs: fold __inode_permission() into inode_permission()
  fs: add RWF_APPEND
  sctp: use vmemdup_user() rather than badly open-coding memdup_user()
  snd_ctl_elem_init_enum_names(): switch to vmemdup_user()
  replace_user_tlv(): switch to vmemdup_user()
  new primitive: vmemdup_user()
  memdup_user(): switch to GFP_USER
  eventfd: fold eventfd_ctx_get() into eventfd_ctx_fileget()
  eventfd: fold eventfd_ctx_read() into eventfd_read()
  eventfd: convert to use anon_inode_getfd()
  nfs4file: get rid of pointless include of btrfs.h
  uvc_v4l2: clean copyin/copyout up
  vme_user: don't use __copy_..._user()
  usx2y: don't bother with memdup_user() for 16-byte structure
  ...
2018-01-31 09:25:20 -08:00
Linus Torvalds
8b0fdf631c Merge branch 'work.mqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull mqueue/bpf vfs cleanups from Al Viro:
 "mqueue and bpf go through rather painful and similar contortions to
  create objects in their dentry trees. Provide a primitive for doing
  that without abusing ->mknod(), switch bpf and mqueue to it.

  Another mqueue-related thing that has ended up in that branch is
  on-demand creation of internal mount (based upon the work of Giuseppe
  Scrivano)"

* 'work.mqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  mqueue: switch to on-demand creation of internal mount
  tidy do_mq_open() up a bit
  mqueue: clean prepare_open() up
  do_mq_open(): move all work prior to dentry_open() into a helper
  mqueue: fold mq_attr_ok() into mqueue_get_inode()
  move dentry_open() calls up into do_mq_open()
  mqueue: switch to vfs_mkobj(), quit abusing ->d_fsdata
  bpf_obj_do_pin(): switch to vfs_mkobj(), quit abusing ->mknod()
  new primitive: vfs_mkobj()
2018-01-30 18:32:21 -08:00
Linus Torvalds
2afe738fc0 Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull userns updates from Eric Biederman:
 "Between the holidays and other distractions only a small amount of
  namespace work made it into my tree this time.

  Just a final cleanup from a revert several kernels ago and a small
  typo fix from Wolffhardt Schwabe"

* 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  fix typo in assignment of fs default overflow gid
  autofs4: Modify autofs_wait to use current_uid() and current_gid()
  userns: Don't fail follow_automount based on s_user_ns
2018-01-30 14:43:12 -08:00
Eric Biggers
4bfd054ae1 fs: fold __inode_permission() into inode_permission()
Since commit 9c630ebefe ("ovl: simplify permission checking"),
overlayfs doesn't call __inode_permission() anymore, which leaves no
users other than inode_permission().  So just fold it back into
inode_permission().

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-01-25 19:34:28 -05:00
Al Viro
8e6c848ece new primitive: vfs_mkobj()
Similar to vfs_create(), but with caller-supplied callback (and
argument for it) to be used instead of ->create().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-01-05 11:53:07 -05:00
Eric W. Biederman
bbc3e47101 userns: Don't fail follow_automount based on s_user_ns
When vfs_submount was added the test to limit automounts from
filesystems that with s_user_ns != &init_user_ns accidentially left
in follow_automount.  The test was never about any security concerns
and was always about how do we implement this for filesystems whose
s_user_ns != &init_user_ns.

At the moment this check makes no difference as there are no
filesystems that both set FS_USERNS_MOUNT and implement d_automount.

Remove this check now while I am thinking about it so there will not
be odd booby traps for someone who does want to make this combination
work.

vfs_submount still needs improvements to allow this combination to work,
and vfs_submount contains a check that presents a warning.

The autofs4 filesystem could be modified to set FS_USERNS_MOUNT and it would
need not work on this code path, as userspace performs the mounts.

Fixes: 93faccbbfa ("fs: Better permission checking for submounts")
Fixes: aeaa4a79ff ("fs: Call d_automount with the filesystems creds")
Acked-by:  Ian Kent <raven@themaw.net>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2017-11-30 17:47:20 -06:00
Ian Kent
5d38f049ce autofs: revert "autofs: fix AT_NO_AUTOMOUNT not being honored"
Commit 42f4614821 ("autofs: fix AT_NO_AUTOMOUNT not being honored")
allowed the fstatat(2) system call to properly honor the AT_NO_AUTOMOUNT
flag but introduced a semantic change.

In order to honor AT_NO_AUTOMOUNT a semantic change was made to the
negative dentry case for stat family system calls in follow_automount().

This changed the unconditional triggering of an automount in this case
to no longer be done and an error returned instead.

This has caused more problems than I expected so reverting the change is
needed.

In a discussion with Neil Brown it was concluded that the automount(8)
daemon can implement this change without kernel modifications.  So that
will be done instead and the autofs module documentation updated with a
description of the problem and what needs to be done by module users for
this specific case.

Link: http://lkml.kernel.org/r/151174730120.6162.3848002191530283984.stgit@pluto.themaw.net
Fixes: 42f4614821 ("autofs: fix AT_NO_AUTOMOUNT not being honored")
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Neil Brown <neilb@suse.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: Colin Walters <walters@redhat.com>
Cc: Ondrej Holy <oholy@redhat.com>
Cc: <stable@vger.kernel.org>	[4.11+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-29 18:40:43 -08:00
Linus Torvalds
ca5b857cb0 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc vfs updates from Al Viro:
 "Assorted stuff, really no common topic here"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  vfs: grab the lock instead of blocking in __fd_install during resizing
  vfs: stop clearing close on exec when closing a fd
  include/linux/fs.h: fix comment about struct address_space
  fs: make fiemap work from compat_ioctl
  coda: fix 'kernel memory exposure attempt' in fsync
  pstore: remove unneeded unlikely()
  vfs: remove unneeded unlikely()
  stubs for mount_bdev() and kill_block_super() in !CONFIG_BLOCK case
  make vfs_ustat() static
  do_handle_open() should be static
  elf_fdpic: fix unused variable warning
  fold destroy_super() into __put_super()
  new helper: destroy_unused_super()
  fix address space warnings in ipc/
  acct.h: get rid of detritus
2017-11-17 12:54:01 -08:00
Linus Torvalds
93f30c73ec Merge branch 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull compat and uaccess updates from Al Viro:

 - {get,put}_compat_sigset() series

 - assorted compat ioctl stuff

 - more set_fs() elimination

 - a few more timespec64 conversions

 - several removals of pointless access_ok() in places where it was
   followed only by non-__ variants of primitives

* 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (24 commits)
  coredump: call do_unlinkat directly instead of sys_unlink
  fs: expose do_unlinkat for built-in callers
  ext4: take handling of EXT4_IOC_GROUP_ADD into a helper, get rid of set_fs()
  ipmi: get rid of pointless access_ok()
  pi433: sanitize ioctl
  cxlflash: get rid of pointless access_ok()
  mtdchar: get rid of pointless access_ok()
  r128: switch compat ioctls to drm_ioctl_kernel()
  selection: get rid of field-by-field copyin
  VT_RESIZEX: get rid of field-by-field copyin
  i2c compat ioctls: move to ->compat_ioctl()
  sched_rr_get_interval(): move compat to native, get rid of set_fs()
  mips: switch to {get,put}_compat_sigset()
  sparc: switch to {get,put}_compat_sigset()
  s390: switch to {get,put}_compat_sigset()
  ppc: switch to {get,put}_compat_sigset()
  parisc: switch to {get,put}_compat_sigset()
  get_compat_sigset()
  get rid of {get,put}_compat_itimerspec()
  io_getevents: Use timespec64 to represent timeouts
  ...
2017-11-17 11:54:55 -08:00
Christoph Hellwig
da2f1362c8 fs: expose do_unlinkat for built-in callers
And make it take a struct filename instead of a user pointer.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-11-10 08:48:46 -05:00
Ingo Molnar
8c5db92a70 Merge branch 'linus' into locking/core, to resolve conflicts
Conflicts:
	include/linux/compiler-clang.h
	include/linux/compiler-gcc.h
	include/linux/compiler-intel.h
	include/uapi/linux/stddef.h

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-07 10:32:44 +01:00
Hirofumi Nakagawa
684e73bee4 vfs: remove unneeded unlikely()
IS_ERR() macro it is already including unlikely().

Signed-off-by: Hirofumi Nakagawa <nklabs@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-11-05 18:30:49 -05:00
Greg Kroah-Hartman
b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Mark Rutland
6aa7de0591 locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE()
Please do not apply this to mainline directly, instead please re-run the
coccinelle script shown below and apply its output.

For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't harmful, and changing them results in
churn.

However, for some features, the read/write distinction is critical to
correct operation. To distinguish these cases, separate read/write
accessors must be used. This patch migrates (most) remaining
ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
coccinelle script:

----
// Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
// WRITE_ONCE()

// $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch

virtual patch

@ depends on patch @
expression E1, E2;
@@

- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)

@ depends on patch @
expression E;
@@

- ACCESS_ONCE(E)
+ READ_ONCE(E)
----

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-25 11:01:08 +02:00
Linus Torvalds
0f0d12728e Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull mount flag updates from Al Viro:
 "Another chunk of fmount preparations from dhowells; only trivial
  conflicts for that part. It separates MS_... bits (very grotty
  mount(2) ABI) from the struct super_block ->s_flags (kernel-internal,
  only a small subset of MS_... stuff).

  This does *not* convert the filesystems to new constants; only the
  infrastructure is done here. The next step in that series is where the
  conflicts would be; that's the conversion of filesystems. It's purely
  mechanical and it's better done after the merge, so if you could run
  something like

	list=$(for i in MS_RDONLY MS_NOSUID MS_NODEV MS_NOEXEC MS_SYNCHRONOUS MS_MANDLOCK MS_DIRSYNC MS_NOATIME MS_NODIRATIME MS_SILENT MS_POSIXACL MS_KERNMOUNT MS_I_VERSION MS_LAZYTIME; do git grep -l $i fs drivers/staging/lustre drivers/mtd ipc mm include/linux; done|sort|uniq|grep -v '^fs/namespace.c$')

	sed -i -e 's/\<MS_RDONLY\>/SB_RDONLY/g' \
	        -e 's/\<MS_NOSUID\>/SB_NOSUID/g' \
	        -e 's/\<MS_NODEV\>/SB_NODEV/g' \
	        -e 's/\<MS_NOEXEC\>/SB_NOEXEC/g' \
	        -e 's/\<MS_SYNCHRONOUS\>/SB_SYNCHRONOUS/g' \
	        -e 's/\<MS_MANDLOCK\>/SB_MANDLOCK/g' \
	        -e 's/\<MS_DIRSYNC\>/SB_DIRSYNC/g' \
	        -e 's/\<MS_NOATIME\>/SB_NOATIME/g' \
	        -e 's/\<MS_NODIRATIME\>/SB_NODIRATIME/g' \
	        -e 's/\<MS_SILENT\>/SB_SILENT/g' \
	        -e 's/\<MS_POSIXACL\>/SB_POSIXACL/g' \
	        -e 's/\<MS_KERNMOUNT\>/SB_KERNMOUNT/g' \
	        -e 's/\<MS_I_VERSION\>/SB_I_VERSION/g' \
	        -e 's/\<MS_LAZYTIME\>/SB_LAZYTIME/g' \
	        $list

  and commit it with something along the lines of 'convert filesystems
  away from use of MS_... constants' as commit message, it would save a
  quite a bit of headache next cycle"

* 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  VFS: Differentiate mount flags (MS_*) from internal superblock flags
  VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb)
  vfs: Add sb_rdonly(sb) to query the MS_RDONLY flag on s_flags
2017-09-14 18:54:01 -07:00
Ian Kent
42f4614821 autofs: fix AT_NO_AUTOMOUNT not being honored
The fstatat(2) and statx() calls can pass the flag AT_NO_AUTOMOUNT which
is meant to clear the LOOKUP_AUTOMOUNT flag and prevent triggering of an
automount by the call.  But this flag is unconditionally cleared for all
stat family system calls except statx().

stat family system calls have always triggered mount requests for the
negative dentry case in follow_automount() which is intended but prevents
the fstatat(2) and statx() AT_NO_AUTOMOUNT case from being handled.

In order to handle the AT_NO_AUTOMOUNT for both system calls the negative
dentry case in follow_automount() needs to be changed to return ENOENT
when the LOOKUP_AUTOMOUNT flag is clear (and the other required flags are
clear).

AFAICT this change doesn't have any noticable side effects and may, in
some use cases (although I didn't see it in testing) prevent unnecessary
callbacks to the automount daemon.

It's also possible that a stat family call has been made with a path that
is in the process of being mounted by some other process.  But stat family
calls should return the automount state of the path as it is "now" so it
shouldn't wait for mount completion.

This is the same semantic as the positive dentry case already handled.

Link: http://lkml.kernel.org/r/150216641255.11652.4204561328197919771.stgit@pluto.themaw.net
Fixes: deccf497d8 ("Make stat/lstat/fstatat pass AT_NO_AUTOMOUNT to vfs_statx()")
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: David Howells <dhowells@redhat.com>
Cc: Colin Walters <walters@redhat.com>
Cc: Ondrej Holy <oholy@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-08 18:26:50 -07:00
Linus Torvalds
e06fdaf40a Now that IPC and other changes have landed, enable manual markings for
randstruct plugin, including the task_struct.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 Comment: Kees Cook <kees@outflux.net>
 
 iQIcBAABCgAGBQJZbRgGAAoJEIly9N/cbcAmk2AQAIL60aQ+9RIcFAXriFhnd7Z2
 x9Jqi9JNc8NgPFXx8GhE4J4eTZ5PwcjgXBpNRWY/laBkRyoBHn24ku09YxrJjmHz
 ZSUsP+/iO9lVeEfbmU9Tnk50afkfwx6bHXBwkiVGQWHtybNVUqA19JbqkHeg8ubx
 myKLGeUv5PPCodRIcBDD0+HaAANcsqtgbDpgmWU8s+IXWwvWCE2p7PuBw7v3HHgH
 qzlPDHYQCRDw+LWsSqPaHj+9mbRO18P/ydMoZHGH4Hl3YYNtty8ZbxnraI3A7zBL
 6mLUVcZ+/l88DqHc5I05T8MmLU1yl2VRxi8/jpMAkg9wkvZ5iNAtlEKIWU6eqsvk
 vaImNOkViLKlWKF+oUD1YdG16d8Segrc6m4MGdI021tb+LoGuUbkY7Tl4ee+3dl/
 9FM+jPv95HjJnyfRNGidh2TKTa9KJkh6DYM9aUnktMFy3ca1h/LuszOiN0LTDiHt
 k5xoFURk98XslJJyXM8FPwXCXiRivrXMZbg5ixNoS4aYSBLv7Cn1M6cPnSOs7UPh
 FqdNPXLRZ+vabSxvEg5+41Ioe0SHqACQIfaSsV5BfF2rrRRdaAxK4h7DBcI6owV2
 7ziBN1nBBq2onYGbARN6ApyCqLcchsKtQfiZ0iFsvW7ZawnkVOOObDTCgPl3tdkr
 403YXzphQVzJtpT5eRV6
 =ngAW
 -----END PGP SIGNATURE-----

Merge tag 'gcc-plugins-v4.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull structure randomization updates from Kees Cook:
 "Now that IPC and other changes have landed, enable manual markings for
  randstruct plugin, including the task_struct.

  This is the rest of what was staged in -next for the gcc-plugins, and
  comes in three patches, largest first:

   - mark "easy" structs with __randomize_layout

   - mark task_struct with an optional anonymous struct to isolate the
     __randomize_layout section

   - mark structs to opt _out_ of automated marking (which will come
     later)

  And, FWIW, this continues to pass allmodconfig (normal and patched to
  enable gcc-plugins) builds of x86_64, i386, arm64, arm, powerpc, and
  s390 for me"

* tag 'gcc-plugins-v4.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  randstruct: opt-out externally exposed function pointer structs
  task_struct: Allow randomized layout
  randstruct: Mark various structs for randomization
2017-07-19 08:55:18 -07:00
David Howells
bc98a42c1f VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb)
Firstly by applying the following with coccinelle's spatch:

	@@ expression SB; @@
	-SB->s_flags & MS_RDONLY
	+sb_rdonly(SB)

to effect the conversion to sb_rdonly(sb), then by applying:

	@@ expression A, SB; @@
	(
	-(!sb_rdonly(SB)) && A
	+!sb_rdonly(SB) && A
	|
	-A != (sb_rdonly(SB))
	+A != sb_rdonly(SB)
	|
	-A == (sb_rdonly(SB))
	+A == sb_rdonly(SB)
	|
	-!(sb_rdonly(SB))
	+!sb_rdonly(SB)
	|
	-A && (sb_rdonly(SB))
	+A && sb_rdonly(SB)
	|
	-A || (sb_rdonly(SB))
	+A || sb_rdonly(SB)
	|
	-(sb_rdonly(SB)) != A
	+sb_rdonly(SB) != A
	|
	-(sb_rdonly(SB)) == A
	+sb_rdonly(SB) == A
	|
	-(sb_rdonly(SB)) && A
	+sb_rdonly(SB) && A
	|
	-(sb_rdonly(SB)) || A
	+sb_rdonly(SB) || A
	)

	@@ expression A, B, SB; @@
	(
	-(sb_rdonly(SB)) ? 1 : 0
	+sb_rdonly(SB)
	|
	-(sb_rdonly(SB)) ? A : B
	+sb_rdonly(SB) ? A : B
	)

to remove left over excess bracketage and finally by applying:

	@@ expression A, SB; @@
	(
	-(A & MS_RDONLY) != sb_rdonly(SB)
	+(bool)(A & MS_RDONLY) != sb_rdonly(SB)
	|
	-(A & MS_RDONLY) == sb_rdonly(SB)
	+(bool)(A & MS_RDONLY) == sb_rdonly(SB)
	)

to make comparisons against the result of sb_rdonly() (which is a bool)
work correctly.

Signed-off-by: David Howells <dhowells@redhat.com>
2017-07-17 08:45:34 +01:00
Linus Torvalds
78dcf73421 Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull ->s_options removal from Al Viro:
 "Preparations for fsmount/fsopen stuff (coming next cycle). Everything
  gets moved to explicit ->show_options(), killing ->s_options off +
  some cosmetic bits around fs/namespace.c and friends. Basically, the
  stuff needed to work with fsmount series with minimum of conflicts
  with other work.

  It's not strictly required for this merge window, but it would reduce
  the PITA during the coming cycle, so it would be nice to have those
  bits and pieces out of the way"

* 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  isofs: Fix isofs_show_options()
  VFS: Kill off s_options and helpers
  orangefs: Implement show_options
  9p: Implement show_options
  isofs: Implement show_options
  afs: Implement show_options
  affs: Implement show_options
  befs: Implement show_options
  spufs: Implement show_options
  bpf: Implement show_options
  ramfs: Implement show_options
  pstore: Implement show_options
  omfs: Implement show_options
  hugetlbfs: Implement show_options
  VFS: Don't use save/replace_mount_options if not using generic_show_options
  VFS: Provide empty name qstr
  VFS: Make get_filesystem() return the affected filesystem
  VFS: Clean up whitespace in fs/namespace.c and fs/super.c
  Provide a function to create a NUL-terminated string from unterminated data
2017-07-15 12:00:42 -07:00
Linus Torvalds
b8d4c1f9f4 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc filesystem updates from Al Viro:
 "Assorted normal VFS / filesystems stuff..."

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  dentry name snapshots
  Make statfs properly return read-only state after emergency remount
  fs/dcache: init in_lookup_hashtable
  minix: Deinline get_block, save 2691 bytes
  fs: Reorder inode_owner_or_capable() to avoid needless
  fs: warn in case userspace lied about modprobe return
2017-07-08 10:50:54 -07:00
Al Viro
49d31c2f38 dentry name snapshots
take_dentry_name_snapshot() takes a safe snapshot of dentry name;
if the name is a short one, it gets copied into caller-supplied
structure, otherwise an extra reference to external name is grabbed
(those are never modified).  In either case the pointer to stable
string is stored into the same structure.

dentry must be held by the caller of take_dentry_name_snapshot(),
but may be freely dropped afterwards - the snapshot will stay
until destroyed by release_dentry_name_snapshot().

Intended use:
	struct name_snapshot s;

	take_dentry_name_snapshot(&s, dentry);
	...
	access s.name
	...
	release_dentry_name_snapshot(&s);

Replaces fsnotify_oldname_...(), gets used in fsnotify to obtain the name
to pass down with event.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-07-07 20:09:10 -04:00
David Howells
cdf01226b2 VFS: Provide empty name qstr
Provide an empty name (ie. "") qstr for general use.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-07-06 03:27:09 -04:00
Kees Cook
3859a271a0 randstruct: Mark various structs for randomization
This marks many critical kernel structures for randomization. These are
structures that have been targeted in the past in security exploits, or
contain functions pointers, pointers to function pointer tables, lists,
workqueues, ref-counters, credentials, permissions, or are otherwise
sensitive. This initial list was extracted from Brad Spengler/PaX Team's
code in the last public patch of grsecurity/PaX based on my understanding
of the code. Changes or omissions from the original code are mine and
don't reflect the original grsecurity/PaX code.

Left out of this list is task_struct, which requires special handling
and will be covered in a subsequent patch.

Signed-off-by: Kees Cook <keescook@chromium.org>
2017-06-30 12:00:51 -07:00
Kees Cook
cc658db47d fs: Reorder inode_owner_or_capable() to avoid needless
Checking for capabilities should be the last operation when performing
access control tests so that PF_SUPERPRIV is set only when it was required
for success (implying that the capability was needed for the operation).

Reported-by: Solar Designer <solar@openwall.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-06-29 20:08:32 -04:00
Jonathan Corbet
6312811be2 Merge remote-tracking branch 'mauro-exp/docbook3' into death-to-docbook
Mauro says:

This patch series convert the remaining DocBooks to ReST.

The first version was originally
send as 3 patch series:

   [PATCH 00/36] Convert DocBook documents to ReST
   [PATCH 0/5] Convert more books to ReST
   [PATCH 00/13] Get rid of DocBook

The lsm book was added as if it were a text file under
Documentation. The plan is to merge it with another file
under Documentation/security, after both this series and
a security Documentation patch series gets merged.

It also adjusts some Sphinx-pedantic errors/warnings on
some kernel-doc markups.

I also added some patches here to add PDF output for all
existing ReST books.
2017-05-18 11:03:08 -06:00
Mauro Carvalho Chehab
0117d4272b fs: add a blank lines on some kernel-doc comments
Sphinx gets confused when it finds identation without a
good reason for it and without a preceding blank line:

	./fs/mpage.c:347: ERROR: Unexpected indentation.
	./fs/namei.c:4303: ERROR: Unexpected indentation.
	./fs/fs-writeback.c:2060: ERROR: Unexpected indentation.

No functional changes.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-05-16 08:44:10 -03:00
Linus Torvalds
050453295f Merge branch 'work.sane_pwd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc vfs updates from Al Viro:
 "Making sure that something like a referral point won't end up as pwd
  or root.

  The main part is the last commit (fixing mntns_install()); that one
  fixes a hard-to-hit race. The fchdir() commit is making fchdir(2) a
  bit more robust - it should be impossible to get opened files (even
  O_PATH ones) for referral points in the first place, so the existing
  checks are OK, but checking the same thing as in chdir(2) is just as
  cheap.

  The path_init() commit removes a redundant check that shouldn't have
  been there in the first place"

* 'work.sane_pwd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  make sure that mntns_install() doesn't end up with referral for root
  path_init(): don't bother with checking MAY_EXEC for LOOKUP_ROOT
  make sure that fchdir() won't accept referral points, etc.
2017-05-12 11:39:59 -07:00
Tetsuo Handa
c718a97514 fs: semove set but not checked AOP_FLAG_UNINTERRUPTIBLE flag
Commit afddba49d1 ("fs: introduce write_begin, write_end, and
perform_write aops") introduced AOP_FLAG_UNINTERRUPTIBLE flag which was
checked in pagecache_write_begin(), but that check was removed by
4e02ed4b4a ("fs: remove prepare_write/commit_write").

Between these two commits, commit d9414774dc ("cifs: Convert cifs to
new aops.") added a check in cifs_write_begin(), but that check was soon
removed by commit a98ee8c1c7 ("[CIFS] fix regression in
cifs_write_begin/cifs_write_end").

Therefore, AOP_FLAG_UNINTERRUPTIBLE flag is checked nowhere.  Let's
remove this flag.  This patch has no functionality changes.

Link: http://lkml.kernel.org/r/1489294781-53494-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-08 17:15:14 -07:00
Linus Torvalds
0302e28dee Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull security subsystem updates from James Morris:
 "Highlights:

  IMA:
   - provide ">" and "<" operators for fowner/uid/euid rules

  KEYS:
   - add a system blacklist keyring

   - add KEYCTL_RESTRICT_KEYRING, exposes keyring link restriction
     functionality to userland via keyctl()

  LSM:
   - harden LSM API with __ro_after_init

   - add prlmit security hook, implement for SELinux

   - revive security_task_alloc hook

  TPM:
   - implement contextual TPM command 'spaces'"

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (98 commits)
  tpm: Fix reference count to main device
  tpm_tis: convert to using locality callbacks
  tpm: fix handling of the TPM 2.0 event logs
  tpm_crb: remove a cruft constant
  keys: select CONFIG_CRYPTO when selecting DH / KDF
  apparmor: Make path_max parameter readonly
  apparmor: fix parameters so that the permission test is bypassed at boot
  apparmor: fix invalid reference to index variable of iterator line 836
  apparmor: use SHASH_DESC_ON_STACK
  security/apparmor/lsm.c: set debug messages
  apparmor: fix boolreturn.cocci warnings
  Smack: Use GFP_KERNEL for smk_netlbl_mls().
  smack: fix double free in smack_parse_opts_str()
  KEYS: add SP800-56A KDF support for DH
  KEYS: Keyring asymmetric key restrict method with chaining
  KEYS: Restrict asymmetric key linkage using a specific keychain
  KEYS: Add a lookup_restriction function for the asymmetric key type
  KEYS: Add KEYCTL_RESTRICT_KEYRING
  KEYS: Consistent ordering for __key_link_begin and restrict check
  KEYS: Add an optional lookup_restriction hook to key_type
  ...
2017-05-03 08:50:52 -07:00
Al Viro
4f757f3cbf make sure that mntns_install() doesn't end up with referral for root
new flag: LOOKUP_DOWN.  If the starting point is overmounted, cross
into whatever's mounted on top, triggering referrals et.al.

Use that instead of follow_down_one() loop in mntns_install(), handle
errors properly.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-04-21 14:05:36 -04:00
Al Viro
93893862fb path_init(): don't bother with checking MAY_EXEC for LOOKUP_ROOT
we'll hit that check in link_path_walk() anyway.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-04-21 14:05:35 -04:00
Linus Torvalds
c0eb027e5a vfs: don't do RCU lookup of empty pathnames
Normal pathname lookup doesn't allow empty pathnames, but using
AT_EMPTY_PATH (with name_to_handle_at() or fstatat(), for example) you
can trigger an empty pathname lookup.

And not only is the RCU lookup in that case entirely unnecessary
(because we'll obviously immediately finalize the end result), it is
actively wrong.

Why? An empth path is a special case that will return the original
'dirfd' dentry - and that dentry may not actually be RCU-free'd,
resulting in a potential use-after-free if we were to initialize the
path lazily under the RCU read lock and depend on complete_walk()
finalizing the dentry.

Found by syzkaller and KASAN.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Reported-by: Vegard Nossum <vegard.nossum@gmail.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-04-15 09:34:52 -07:00
Stephen Smalley
2a4c224269 fs: switch order of CAP_DAC_OVERRIDE and CAP_DAC_READ_SEARCH checks
generic_permission() presently checks CAP_DAC_OVERRIDE prior to
CAP_DAC_READ_SEARCH.  This can cause misleading audit messages when
using a LSM such as SELinux or AppArmor, since CAP_DAC_OVERRIDE
may not be required for the operation.  Flip the order of the
tests so that CAP_DAC_OVERRIDE is only checked when required for
the operation.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-29 17:33:11 -04:00
Al Viro
653a7746fa Merge remote-tracking branch 'ovl/for-viro' into for-linus
Overlayfs-related series from Miklos and Amir
2017-03-02 06:41:22 -05:00
Al Viro
f6c99aad4d Merge branch 'work.namei' into for-linus 2017-03-02 06:41:12 -05:00
Amir Goldstein
af7bd4dc13 vfs: create vfs helper vfs_tmpfile()
Factor out some common vfs bits from do_tmpfile()
to be used by overlayfs for concurrent copy up.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-02-07 15:05:04 +01:00
Eric W. Biederman
93faccbbfa fs: Better permission checking for submounts
To support unprivileged users mounting filesystems two permission
checks have to be performed: a test to see if the user allowed to
create a mount in the mount namespace, and a test to see if
the user is allowed to access the specified filesystem.

The automount case is special in that mounting the original filesystem
grants permission to mount the sub-filesystems, to any user who
happens to stumble across the their mountpoint and satisfies the
ordinary filesystem permission checks.

Attempting to handle the automount case by using override_creds
almost works.  It preserves the idea that permission to mount
the original filesystem is permission to mount the sub-filesystem.
Unfortunately using override_creds messes up the filesystems
ordinary permission checks.

Solve this by being explicit that a mount is a submount by introducing
vfs_submount, and using it where appropriate.

vfs_submount uses a new mount internal mount flags MS_SUBMOUNT, to let
sget and friends know that a mount is a submount so they can take appropriate
action.

sget and sget_userns are modified to not perform any permission checks
on submounts.

follow_automount is modified to stop using override_creds as that
has proven problemantic.

do_mount is modified to always remove the new MS_SUBMOUNT flag so
that we know userspace will never by able to specify it.

autofs4 is modified to stop using current_real_cred that was put in
there to handle the previous version of submount permission checking.

cifs is modified to pass the mountpoint all of the way down to vfs_submount.

debugfs is modified to pass the mountpoint all of the way down to
trace_automount by adding a new parameter.  To make this change easier
a new typedef debugfs_automount_t is introduced to capture the type of
the debugfs automount function.

Cc: stable@vger.kernel.org
Fixes: 069d5ac9ae ("autofs:  Fix automounts by using current_real_cred()->uid")
Fixes: aeaa4a79ff ("fs: Call d_automount with the filesystems creds")
Reviewed-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2017-02-02 04:36:12 +13:00
Seth Forshee
1328c72700 vfs: open() with O_CREAT should not create inodes with unknown ids
may_create() rejects creation of inodes with ids which lack a
mapping into s_user_ns. However for O_CREAT may_o_create() is
is used instead. Add a similar check there.

Fixes: 036d523641 ("vfs: Don't create inodes with a uid or gid unknown to the vfs")
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2017-02-01 18:17:05 +13:00
Al Viro
4675ac39b5 namei.c: split unlazy_walk()
In all but one case, the last two arguments are NULL and 0 resp.;
almost everyone just wants to switch nameidata to non-RCU mode.
The only exception is lookup_fast(), where we have a child dentry
we want to legitimize as well.  Split these two cases.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-01-09 22:29:15 -05:00
Al Viro
a89f833737 namei.c: fold the check for DCACHE_OP_REVALIDATE into d_revalidate()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-01-09 22:25:28 -05:00
Al Viro
209a7fb210 lookup_fast(): clean up the logics around the fallback to non-rcu mode
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-01-09 01:35:39 -05:00
Al Viro
ad1633a151 namei: fold unlazy_link() into its sole caller
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-01-08 22:35:31 -05:00
Linus Torvalds
7c0f6ba682 Replace <asm/uaccess.h> with <linux/uaccess.h> globally
This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-24 11:46:01 -08:00
Linus Torvalds
231753ef78 Merge uncontroversial parts of branch 'readlink' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull partial readlink cleanups from Miklos Szeredi.

This is the uncontroversial part of the readlink cleanup patch-set that
simplifies the default readlink handling.

Miklos and Al are still discussing the rest of the series.

* git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  vfs: make generic_readlink() static
  vfs: remove ".readlink = generic_readlink" assignments
  vfs: default to generic_readlink()
  vfs: replace calling i_op->readlink with vfs_readlink()
  proc/self: use generic_readlink
  ecryptfs: use vfs_get_link()
  bad_inode: add missing i_op initializers
2016-12-17 19:16:12 -08:00
Linus Torvalds
0110c350c8 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull more vfs updates from Al Viro:
 "In this pile:

   - autofs-namespace series
   - dedupe stuff
   - more struct path constification"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (40 commits)
  ocfs2: implement the VFS clone_range, copy_range, and dedupe_range features
  ocfs2: charge quota for reflinked blocks
  ocfs2: fix bad pointer cast
  ocfs2: always unlock when completing dio writes
  ocfs2: don't eat io errors during _dio_end_io_write
  ocfs2: budget for extent tree splits when adding refcount flag
  ocfs2: prohibit refcounted swapfiles
  ocfs2: add newlines to some error messages
  ocfs2: convert inode refcount test to a helper
  simple_write_end(): don't zero in short copy into uptodate
  exofs: don't mess with simple_write_{begin,end}
  9p: saner ->write_end() on failing copy into non-uptodate page
  fix gfs2_stuffed_write_end() on short copies
  fix ceph_write_end()
  nfs_write_end(): fix handling of short copies
  vfs: refactor clone/dedupe_file_range common functions
  fs: try to clone files first in vfs_copy_file_range
  vfs: misc struct path constification
  namespace.c: constify struct path passed to a bunch of primitives
  quota: constify struct path in quota_on
  ...
2016-12-17 18:44:00 -08:00
Al Viro
9763f7a4a5 Merge branch 'work.autofs' into for-linus
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-16 16:34:52 -05:00
Linus Torvalds
ff0f962ca3 Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs updates from Miklos Szeredi:
 "This update contains:

   - try to clone on copy-up

   - allow renaming a directory

   - split source into managable chunks

   - misc cleanups and fixes

  It does not contain the read-only fd data inconsistency fix, which Al
  didn't like. I'll leave that to the next year..."

* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (36 commits)
  ovl: fix reStructuredText syntax errors in documentation
  ovl: fix return value of ovl_fill_super
  ovl: clean up kstat usage
  ovl: fold ovl_copy_up_truncate() into ovl_copy_up()
  ovl: create directories inside merged parent opaque
  ovl: opaque cleanup
  ovl: show redirect_dir mount option
  ovl: allow setting max size of redirect
  ovl: allow redirect_dir to default to "on"
  ovl: check for emptiness of redirect dir
  ovl: redirect on rename-dir
  ovl: lookup redirects
  ovl: consolidate lookup for underlying layers
  ovl: fix nested overlayfs mount
  ovl: check namelen
  ovl: split super.c
  ovl: use d_is_dir()
  ovl: simplify lookup
  ovl: check lower existence of rename target
  ovl: rename: simplify handling of lower/merged directory
  ...
2016-12-16 10:58:12 -08:00
Miklos Szeredi
8d3e293637 Revert "vfs: rename: check backing inode being equal"
This reverts commit 9409e22acd.

Since commit 51f7e52dc9 ("ovl: share inode for hard link") there's no
need to call d_real_inode() to check two overlay inodes for equality.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16 11:02:54 +01:00
Miklos Szeredi
d16744ec8a vfs: make generic_readlink() static
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-09 16:45:04 +01:00
Miklos Szeredi
dfeef68862 vfs: remove ".readlink = generic_readlink" assignments
If .readlink == NULL implies generic_readlink().

Generated by:

to_del="\.readlink.*=.*generic_readlink"
for i in `git grep -l $to_del`; do sed -i "/$to_del"/d $i; done

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-09 16:45:04 +01:00
Miklos Szeredi
76fca90e9f vfs: default to generic_readlink()
If i_op->readlink is NULL, but i_op->get_link is set then vfs_readlink()
defaults to calling generic_readlink().

The IOP_DEFAULT_READLINK flag indicates that the above conditions are met
and the default action can be taken.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-09 16:45:04 +01:00
Miklos Szeredi
fd4a0edf2a vfs: replace calling i_op->readlink with vfs_readlink()
Also check d_is_symlink() in callers instead of inode->i_op->readlink
because following patches will allow NULL ->readlink for symlinks.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-09 16:45:04 +01:00
Al Viro
8f64fb1cce namei: fold should_follow_link() with the step into not-followed link
All callers are followed by the same boilerplate - "if it has returned
0, update nd->path/inode/seq - we are not following a symlink here".
Pull it into the function itself, renaming it into step_into().
Rename WALK_GET to WALK_FOLLOW, while we are at it - more descriptive
name.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 19:11:58 -05:00
Al Viro
31d66bcd3f namei: pass both WALK_GET and WALK_MORE to should_follow_link()
... and pull put_link() logics into it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 19:11:58 -05:00
Al Viro
1c4ff1a87e namei: invert WALK_PUT logics
... turning the condition for put_link() in walk_component() into
"WALK_MORE not passed and depth is non-zero".  Again, makes for
simpler arguments.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 19:11:57 -05:00
Al Viro
7f49b47109 namei: shift interpretation of LOOKUP_FOLLOW inside should_follow_link()
Simplifies the arguments both for it and for walk_component()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 19:11:57 -05:00
Al Viro
ba8f46135a namei: saner calling conventions for mountpoint_last()
leave the result in nd->path, have caller do follow_mount() and
copy it to the final destination.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 19:11:57 -05:00
Al Viro
c1d4dd2767 namei.c: get rid of user_path_parent()
direct use of filename_parentat() is just as readable

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 19:11:57 -05:00
Al Viro
f0bb5aaf2c vfs: misc struct path constification
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 19:03:49 -05:00
Ian Kent
fb5f51c742 vfs: change d_manage() to take a struct path
For the autofs module to be able to reliably check if a dentry is a
mountpoint in a multiple namespace environment the ->d_manage() dentry
operation will need to take a path argument instead of a dentry.

Link: http://lkml.kernel.org/r/20161011053352.27645.83962.stgit@pluto.themaw.net
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-02 22:15:53 -05:00
Linus Torvalds
1a892b485f Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs updates from Miklos Szeredi:
 "This update contains fixes to the "use mounter's permission to access
  underlying layers" area, and miscellaneous other fixes and cleanups.

  No new features this time"

* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: use vfs_get_link()
  vfs: add vfs_get_link() helper
  ovl: use generic_readlink
  ovl: explain error values when removing acl from workdir
  ovl: Fix info leak in ovl_lookup_temp()
  ovl: during copy up, switch to mounter's creds early
  ovl: lookup: do getxattr with mounter's permission
  ovl: copy_up_xattr(): use strnlen
2016-10-14 17:23:33 -07:00
Miklos Szeredi
d60874cd58 vfs: add vfs_get_link() helper
This helper is for filesystems that want to read the symlink and are better
off with the get_link() interface (returning a char *) rather than the
readlink() interface (copy into a userspace buffer).

Also call the LSM hook for readlink (not get_link) since this is for
symlink reading not following.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-10-14 11:16:47 +02:00
Linus Torvalds
101105b171 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull more vfs updates from Al Viro:
 ">rename2() work from Miklos + current_time() from Deepa"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: Replace current_fs_time() with current_time()
  fs: Replace CURRENT_TIME_SEC with current_time() for inode timestamps
  fs: Replace CURRENT_TIME with current_time() for inode timestamps
  fs: proc: Delete inode time initializations in proc_alloc_inode()
  vfs: Add current_time() api
  vfs: add note about i_op->rename changes to porting
  fs: rename "rename2" i_op to "rename"
  vfs: remove unused i_op->rename
  fs: make remaining filesystems use .rename2
  libfs: support RENAME_NOREPLACE in simple_rename()
  fs: support RENAME_NOREPLACE for local filesystems
  ncpfs: fix unused variable warning
2016-10-10 20:16:43 -07:00
Miklos Szeredi
2773bf00ae fs: rename "rename2" i_op to "rename"
Generated patch:

sed -i "s/\.rename2\t/\.rename\t\t/" `git grep -wl rename2`
sed -i "s/\brename2\b/rename/g" `git grep -wl rename2`

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-09-27 11:03:58 +02:00
Miklos Szeredi
18fc84dafa vfs: remove unused i_op->rename
No in-tree uses remain.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-09-27 11:03:58 +02:00
Miklos Szeredi
598e3c8f72 vfs: update ovl inode before relatime check
On overlayfs relatime_need_update() needs inode times to be correct on
overlay inode.  But i_mtime and i_ctime are updated by filesystem code on
underlying inode only, so they will be out-of-date on the overlay inode.

This patch copies the times from the underlying inode if needed.  This
can't be done if called from RCU lookup (link following) but link m/ctime
are not updated by fs, so this is all right.

This patch doesn't change functionality for anything but overlayfs.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-09-16 12:44:20 +02:00
Eryu Guan
337684a174 fs: return EPERM on immutable inode
In most cases, EPERM is returned on immutable inode, and there're only a
few places returning EACCES. I noticed this when running LTP on
overlayfs, setxattr03 failed due to unexpected EACCES on immutable
inode.

So converting all EACCES to EPERM on immutable inode.

Acked-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-07 10:03:31 -04:00
Linus Torvalds
a867d7349e Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull userns vfs updates from Eric Biederman:
 "This tree contains some very long awaited work on generalizing the
  user namespace support for mounting filesystems to include filesystems
  with a backing store.  The real world target is fuse but the goal is
  to update the vfs to allow any filesystem to be supported.  This
  patchset is based on a lot of code review and testing to approach that
  goal.

  While looking at what is needed to support the fuse filesystem it
  became clear that there were things like xattrs for security modules
  that needed special treatment.  That the resolution of those concerns
  would not be fuse specific.  That sorting out these general issues
  made most sense at the generic level, where the right people could be
  drawn into the conversation, and the issues could be solved for
  everyone.

  At a high level what this patchset does a couple of simple things:

   - Add a user namespace owner (s_user_ns) to struct super_block.

   - Teach the vfs to handle filesystem uids and gids not mapping into
     to kuids and kgids and being reported as INVALID_UID and
     INVALID_GID in vfs data structures.

  By assigning a user namespace owner filesystems that are mounted with
  only user namespace privilege can be detected.  This allows security
  modules and the like to know which mounts may not be trusted.  This
  also allows the set of uids and gids that are communicated to the
  filesystem to be capped at the set of kuids and kgids that are in the
  owning user namespace of the filesystem.

  One of the crazier corner casees this handles is the case of inodes
  whose i_uid or i_gid are not mapped into the vfs.  Most of the code
  simply doesn't care but it is easy to confuse the inode writeback path
  so no operation that could cause an inode write-back is permitted for
  such inodes (aka only reads are allowed).

  This set of changes starts out by cleaning up the code paths involved
  in user namespace permirted mounts.  Then when things are clean enough
  adds code that cleanly sets s_user_ns.  Then additional restrictions
  are added that are possible now that the filesystem superblock
  contains owner information.

  These changes should not affect anyone in practice, but there are some
  parts of these restrictions that are changes in behavior.

   - Andy's restriction on suid executables that does not honor the
     suid bit when the path is from another mount namespace (think
     /proc/[pid]/fd/) or when the filesystem was mounted by a less
     privileged user.

   - The replacement of the user namespace implicit setting of MNT_NODEV
     with implicitly setting SB_I_NODEV on the filesystem superblock
     instead.

     Using SB_I_NODEV is a stronger form that happens to make this state
     user invisible.  The user visibility can be managed but it caused
     problems when it was introduced from applications reasonably
     expecting mount flags to be what they were set to.

  There is a little bit of work remaining before it is safe to support
  mounting filesystems with backing store in user namespaces, beyond
  what is in this set of changes.

   - Verifying the mounter has permission to read/write the block device
     during mount.

   - Teaching the integrity modules IMA and EVM to handle filesystems
     mounted with only user namespace root and to reduce trust in their
     security xattrs accordingly.

   - Capturing the mounters credentials and using that for permission
     checks in d_automount and the like.  (Given that overlayfs already
     does this, and we need the work in d_automount it make sense to
     generalize this case).

  Furthermore there are a few changes that are on the wishlist:

   - Get all filesystems supporting posix acls using the generic posix
     acls so that posix_acl_fix_xattr_from_user and
     posix_acl_fix_xattr_to_user may be removed.  [Maintainability]

   - Reducing the permission checks in places such as remount to allow
     the superblock owner to perform them.

   - Allowing the superblock owner to chown files with unmapped uids and
     gids to something that is mapped so the files may be treated
     normally.

  I am not considering even obvious relaxations of permission checks
  until it is clear there are no more corner cases that need to be
  locked down and handled generically.

  Many thanks to Seth Forshee who kept this code alive, and putting up
  with me rewriting substantial portions of what he did to handle more
  corner cases, and for his diligent testing and reviewing of my
  changes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (30 commits)
  fs: Call d_automount with the filesystems creds
  fs: Update i_[ug]id_(read|write) to translate relative to s_user_ns
  evm: Translate user/group ids relative to s_user_ns when computing HMAC
  dquot: For now explicitly don't support filesystems outside of init_user_ns
  quota: Handle quota data stored in s_user_ns in quota_setxquota
  quota: Ensure qids map to the filesystem
  vfs: Don't create inodes with a uid or gid unknown to the vfs
  vfs: Don't modify inodes with a uid or gid unknown to the vfs
  cred: Reject inodes with invalid ids in set_create_file_as()
  fs: Check for invalid i_uid in may_follow_link()
  vfs: Verify acls are valid within superblock's s_user_ns.
  userns: Handle -1 in k[ug]id_has_mapping when !CONFIG_USER_NS
  fs: Refuse uid/gid changes which don't map into s_user_ns
  selinux: Add support for unprivileged mounts from user namespaces
  Smack: Handle labels consistently in untrusted mounts
  Smack: Add support for unprivileged mounts from user namespaces
  fs: Treat foreign mounts as nosuid
  fs: Limit file caps to the user namespace of the super block
  userns: Remove the now unnecessary FS_USERNS_DEV_MOUNT flag
  userns: Remove implicit MNT_NODEV fragility.
  ...
2016-07-29 15:54:19 -07:00
Linus Torvalds
20d00ee829 Revert "vfs: add lookup_hash() helper"
This reverts commit 3c9fe8cdff.

As Miklos points out in commit c1b2cc1a76, the "lookup_hash()" helper
is now unused, and in fact, with the hash salting changes, since the
hash of a dentry name now depends on the directory dentry it is in, the
helper function isn't even really likely to be useful.

So rather than keep it around in case somebody else might end up finding
a use for it, let's just remove the helper and not trick people into
thinking it might be a useful thing.

For example, I had obviously completely missed how the helper didn't
follow the normal dentry hashing patterns, and how the hash salting
patch broke overlayfs.  Things would quietly build and look sane, but
not work.

Suggested-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-29 12:17:52 -07:00
Linus Torvalds
6784725ab0 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs updates from Al Viro:
 "Assorted cleanups and fixes.

  Probably the most interesting part long-term is ->d_init() - that will
  have a bunch of followups in (at least) ceph and lustre, but we'll
  need to sort the barrier-related rules before it can get used for
  really non-trivial stuff.

  Another fun thing is the merge of ->d_iput() callers (dentry_iput()
  and dentry_unlink_inode()) and a bunch of ->d_compare() ones (all
  except the one in __d_lookup_lru())"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (26 commits)
  fs/dcache.c: avoid soft-lockup in dput()
  vfs: new d_init method
  vfs: Update lookup_dcache() comment
  bdev: get rid of ->bd_inodes
  Remove last traces of ->sync_page
  new helper: d_same_name()
  dentry_cmp(): use lockless_dereference() instead of smp_read_barrier_depends()
  vfs: clean up documentation
  vfs: document ->d_real()
  vfs: merge .d_select_inode() into .d_real()
  unify dentry_iput() and dentry_unlink_inode()
  binfmt_misc: ->s_root is not going anywhere
  drop redundant ->owner initializations
  ufs: get rid of redundant checks
  orangefs: constify inode_operations
  missed comment updates from ->direct_IO() prototype change
  file_inode(f)->i_mapping is f->f_mapping
  trim fsnotify hooks a bit
  9p: new helper - v9fs_parent_fid()
  debugfs: ->d_parent is never NULL or negative
  ...
2016-07-28 12:59:05 -07:00
Oleg Drokin
f4fdace947 vfs: Update lookup_dcache() comment
commit 6c51e513a3 ("lookup_dcache(): lift d_alloc() into callers")
removed the need_lookup argument from lookup_dcache(), but the
comment was forgotten. Also it no longer allocates a new dentry
if nothing was found.

Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-07-24 16:35:02 -04:00
Eric W. Biederman
aeaa4a79ff fs: Call d_automount with the filesystems creds
Seth Forshee reported a mount regression in nfs autmounts
with "fs: Add user namespace member to struct super_block".

It turns out that the assumption that current->cred is something
reasonable during mount while necessary to improve support of
unprivileged mounts is wrong in the automount path.

To fix the existing filesystems override current->cred with the
init_cred before calling d_automount and restore current->cred after
d_automount completes.

To support unprivileged mounts would require a more nuanced cred
selection, so fail on unprivileged mounts for the time being.  As none
of the filesystems that currently set FS_USERNS_MOUNT implement
d_automount this check is only good for preventing future problems.

Fixes: 6e4eab577a ("fs: Add user namespace member to struct super_block")
Tested-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-07-23 14:51:26 -05:00
Eric W. Biederman
036d523641 vfs: Don't create inodes with a uid or gid unknown to the vfs
It is expected that filesystems can not represent uids and gids from
outside of their user namespace.  Keep things simple by not even
trying to create filesystem nodes with non-sense uids and gids.

Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-07-05 15:11:47 -05:00
Eric W. Biederman
0bd23d09b8 vfs: Don't modify inodes with a uid or gid unknown to the vfs
When a filesystem outside of init_user_ns is mounted it could have
uids and gids stored in it that do not map to init_user_ns.

The plan is to allow those filesystems to set i_uid to INVALID_UID and
i_gid to INVALID_GID for unmapped uids and gids and then to handle
that strange case in the vfs to ensure there is consistent robust
handling of the weirdness.

Upon a careful review of the vfs and filesystems about the only case
where there is any possibility of confusion or trouble is when the
inode is written back to disk.  In that case filesystems typically
read the inode->i_uid and inode->i_gid and write them to disk even
when just an inode timestamp is being updated.

Which leads to a rule that is very simple to implement and understand
inodes whose i_uid or i_gid is not valid may not be written.

In dealing with access times this means treat those inodes as if the
inode flag S_NOATIME was set.  Reads of the inodes appear safe and
useful, but any write or modification is disallowed.  The only inode
write that is allowed is a chown that sets the uid and gid on the
inode to valid values.  After such a chown the inode is normal and may
be treated as such.

Denying all writes to inodes with uids or gids unknown to the vfs also
prevents several oddball cases where corruption would have occurred
because the vfs does not have complete information.

One problem case that is prevented is attempting to use the gid of a
directory for new inodes where the directories sgid bit is set but the
directories gid is not mapped.

Another problem case avoided is attempting to update the evm hash
after setxattr, removexattr, and setattr.  As the evm hash includeds
the inode->i_uid or inode->i_gid not knowning the uid or gid prevents
a correct evm hash from being computed.  evm hash verification also
fails when i_uid or i_gid is unknown but that is essentially harmless
as it does not cause filesystem corruption.

Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-07-05 15:06:46 -05:00
Seth Forshee
2d7f9e2ad3 fs: Check for invalid i_uid in may_follow_link()
Filesystem uids which don't map into a user namespace may result
in inode->i_uid being INVALID_UID. A symlink and its parent
could have different owners in the filesystem can both get
mapped to INVALID_UID, which may result in following a symlink
when this would not have otherwise been permitted when protected
symlinks are enabled.

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2016-06-30 18:05:09 -05:00
Miklos Szeredi
2d902671ce vfs: merge .d_select_inode() into .d_real()
The two methods essentially do the same: find the real dentry/inode
belonging to an overlay dentry.  The difference is in the usage:

vfs_open() uses ->d_select_inode() and expects the function to perform
copy-up if necessary based on the open flags argument.

file_dentry() uses ->d_real() passing in the overlay dentry as well as the
underlying inode.

vfs_rename() uses ->d_select_inode() but passes zero flags.  ->d_real()
with a zero inode would have worked just as well here.

This patch merges the functionality of ->d_select_inode() into ->d_real()
by adding an 'open_flags' argument to the latter.

[Al Viro] Make the signature of d_real() match that of ->d_real() again.
And constify the inode argument, while we are at it.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-06-30 08:53:27 +02:00
Eric W. Biederman
a2982cc922 vfs: Generalize filesystem nodev handling.
Introduce a function may_open_dev that tests MNT_NODEV and a new
superblock flab SB_I_NODEV.  Use this new function in all of the
places where MNT_NODEV was previously tested.

Add the new SB_I_NODEV s_iflag to proc, sysfs, and mqueuefs as those
filesystems should never support device nodes, and a simple superblock
flags makes that very hard to get wrong.  With SB_I_NODEV set if any
device nodes somehow manage to show up on on a filesystem those
device nodes will be unopenable.

Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-06-23 15:41:57 -05:00
Linus Torvalds
8387ff2577 vfs: make the string hashes salt the hash
We always mixed in the parent pointer into the dentry name hash, but we
did it late at lookup time.  It turns out that we can simplify that
lookup-time action by salting the hash with the parent pointer early
instead of late.

A few other users of our string hashes also wanted to mix in their own
pointers into the hash, and those are updated to use the same mechanism.

Hash users that don't have any particular initial salt can just use the
NULL pointer as a no-salt.

Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: George Spelvin <linux@sciencehorizons.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-10 20:21:46 -07:00
Linus Torvalds
c8ae067f26 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs fixes from Al Viro:
 "Fixes for crap of assorted ages: EOPENSTALE one is 4.2+, autofs one is
  4.6, d_walk - 3.2+.

  The atomic_open() and coredump ones are regressions from this window"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  coredump: fix dumping through pipes
  fix a regression in atomic_open()
  fix d_walk()/non-delayed __d_free() race
  autofs braino fix for do_last()
  fix EOPENSTALE bug in do_last()
2016-06-07 20:41:36 -07:00
Al Viro
a01e718f72 fix a regression in atomic_open()
open("/foo/no_such_file", O_RDONLY | O_CREAT) on should fail with
EACCES when /foo is not writable; failing with ENOENT is obviously
wrong.  That got broken by a braino introduced when moving the
creat_error logics from atomic_open() to lookup_open().  Easy to
fix, fortunately.

Spotted-by: "Yan, Zheng" <ukernel@gmail.com>
Tested-by: "Yan, Zheng" <ukernel@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-06-07 21:53:51 -04:00
Eric W. Biederman
eedf265aa0 devpts: Make each mount of devpts an independent filesystem.
The /dev/ptmx device node is changed to lookup the directory entry "pts"
in the same directory as the /dev/ptmx device node was opened in.  If
there is a "pts" entry and that entry is a devpts filesystem /dev/ptmx
uses that filesystem.  Otherwise the open of /dev/ptmx fails.

The DEVPTS_MULTIPLE_INSTANCES configuration option is removed, so that
userspace can now safely depend on each mount of devpts creating a new
instance of the filesystem.

Each mount of devpts is now a separate and equal filesystem.

Reserved ttys are now available to all instances of devpts where the
mounter is in the initial mount namespace.

A new vfs helper path_pts is introduced that finds a directory entry
named "pts" in the directory of the passed in path, and changes the
passed in path to point to it.  The helper path_pts uses a function
path_parent_directory that was factored out of follow_dotdot.

In the implementation of devpts:
 - devpts_mnt is killed as it is no longer meaningful if all mounts of
   devpts are equal.
 - pts_sb_from_inode is replaced by just inode->i_sb as all cached
   inodes in the tty layer are now from the devpts filesystem.
 - devpts_add_ref is rolled into the new function devpts_ptmx.  And the
   unnecessary inode hold is removed.
 - devpts_del_ref is renamed devpts_release and reduced to just a
   deacrivate_super.
 - The newinstance mount option continues to be accepted but is now
   ignored.

In devpts_fs.h definitions for when !CONFIG_UNIX98_PTYS are removed as
they are never used.

Documentation/filesystems/devices.txt is updated to describe the current
situation.

This has been verified to work properly on openwrt-15.05, centos5,
centos6, centos7, debian-6.0.2, debian-7.9, debian-8.2, ubuntu-14.04.3,
ubuntu-15.10, fedora23, magia-5, mint-17.3, opensuse-42.1,
slackware-14.1, gentoo-20151225 (13.0?), archlinux-2015-12-01.  With the
caveat that on centos6 and on slackware-14.1 that there wind up being
two instances of the devpts filesystem mounted on /dev/pts, the lower
copy does not end up getting used.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Greg KH <greg@kroah.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Serge Hallyn <serge.hallyn@ubuntu.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Jann Horn <jann@thejh.net>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Florian Weimer <fw@deneb.enyo.de>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-05 10:36:01 -07:00
Al Viro
e6ec03a25f autofs braino fix for do_last()
It's an analogue of commit 7500c38a (fix the braino in "namei:
massage lookup_slow() to be usable by lookup_one_len_unlocked()").
The same problem (->lookup()-returned unhashed negative dentry
just might be an autofs one with ->d_manage() that would wait
until the daemon makes it positive) applies in do_last() - we
need to do follow_managed() first.

Fortunately, remaining callers of follow_managed() are OK - only
autofs has that weirdness (negative dentry that does not mean
an instant -ENOENT)) and autofs never has its negative dentries
hashed, so we can't pick one from a dcache lookup.

->d_manage() is a bloody mess ;-/

Cc: stable@vger.kernel.org # v4.6
Spotted-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-06-05 00:23:09 -04:00
Al Viro
fac7d1917d fix EOPENSTALE bug in do_last()
EOPENSTALE occuring at the last component of a trailing symlink ends up
with do_last() retrying its lookup.  After the symlink body has been
discarded.  The thing is, all this retry_lookup logics in there is not
needed at all - the upper layers will do the right thing if we simply
return that -EOPENSTALE as we would with any other error.  Trying to
microoptimize in do_last() is a lot of headache for no good reason.

Cc: stable@vger.kernel.org # v4.2+
Tested-by: Oleg Drokin <green@linuxhacker.ru>
Reviewed-and-Tested-by: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-06-04 11:59:04 -04:00
George Spelvin
e0ab7af9bd hash_string: Fix zero-length case for !DCACHE_WORD_ACCESS
The self-test was updated to cover zero-length strings; the function
needs to be updated, too.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Fixes: fcfd2fbf22 ("fs/namei.c: Add hashlen_string() function")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-29 07:33:47 -07:00
George Spelvin
f2a031b66e Rename other copy of hash_string to hashlen_string
The original name was simply hash_string(), but that conflicted with a
function with that name in drivers/base/power/trace.c, and I decided
that calling it "hashlen_" was better anyway.

But you have to do it in two places.

[ This caused build errors for architectures that don't define
  CONFIG_DCACHE_WORD_ACCESS   - Linus ]

Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Fixes: fcfd2fbf22 ("fs/namei.c: Add hashlen_string() function")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-28 22:34:33 -07:00
Linus Torvalds
7e0fb73c52 Merge branch 'hash' of git://ftp.sciencehorizons.net/linux
Pull string hash improvements from George Spelvin:
 "This series does several related things:

   - Makes the dcache hash (fs/namei.c) useful for general kernel use.

     (Thanks to Bruce for noticing the zero-length corner case)

   - Converts the string hashes in <linux/sunrpc/svcauth.h> to use the
     above.

   - Avoids 64-bit multiplies in hash_64() on 32-bit platforms.  Two
     32-bit multiplies will do well enough.

   - Rids the world of the bad hash multipliers in hash_32.

     This finishes the job started in commit 689de1d6ca ("Minimal
     fix-up of bad hashing behavior of hash_64()")

     The vast majority of Linux architectures have hardware support for
     32x32-bit multiply and so derive no benefit from "simplified"
     multipliers.

     The few processors that do not (68000, h8/300 and some models of
     Microblaze) have arch-specific implementations added.  Those
     patches are last in the series.

   - Overhauls the dcache hash mixing.

     The patch in commit 0fed3ac866 ("namei: Improve hash mixing if
     CONFIG_DCACHE_WORD_ACCESS") was an off-the-cuff suggestion.
     Replaced with a much more careful design that's simultaneously
     faster and better.  (My own invention, as there was noting suitable
     in the literature I could find.  Comments welcome!)

   - Modify the hash_name() loop to skip the initial HASH_MIX().  This
     would let us salt the hash if we ever wanted to.

   - Sort out partial_name_hash().

     The hash function is declared as using a long state, even though
     it's truncated to 32 bits at the end and the extra internal state
     contributes nothing to the result.  And some callers do odd things:

      - fs/hfs/string.c only allocates 32 bits of state
      - fs/hfsplus/unicode.c uses it to hash 16-bit unicode symbols not bytes

   - Modify bytemask_from_count to handle inputs of 1..sizeof(long)
     rather than 0..sizeof(long)-1.  This would simplify users other
     than full_name_hash"

  Special thanks to Bruce Fields for testing and finding bugs in v1.  (I
  learned some humbling lessons about "obviously correct" code.)

  On the arch-specific front, the m68k assembly has been tested in a
  standalone test harness, I've been in contact with the Microblaze
  maintainers who mostly don't care, as the hardware multiplier is never
  omitted in real-world applications, and I haven't heard anything from
  the H8/300 world"

* 'hash' of git://ftp.sciencehorizons.net/linux:
  h8300: Add <asm/hash.h>
  microblaze: Add <asm/hash.h>
  m68k: Add <asm/hash.h>
  <linux/hash.h>: Add support for architecture-specific functions
  fs/namei.c: Improve dcache hash function
  Eliminate bad hash multipliers from hash_32() and  hash_64()
  Change hash_64() return value to 32 bits
  <linux/sunrpc/svcauth.h>: Define hash_str() in terms of hashlen_string()
  fs/namei.c: Add hashlen_string() function
  Pull out string hash to <linux/stringhash.h>
2016-05-28 16:15:25 -07:00
George Spelvin
468a942852 <linux/hash.h>: Add support for architecture-specific functions
This is just the infrastructure; there are no users yet.

This is modelled on CONFIG_ARCH_RANDOM; a CONFIG_ symbol declares
the existence of <asm/hash.h>.

That file may define its own versions of various functions, and define
HAVE_* symbols (no CONFIG_ prefix!) to suppress the generic ones.

Included is a self-test (in lib/test_hash.c) that verifies the basics.
It is NOT in general required that the arch-specific functions compute
the same thing as the generic, but if a HAVE_* symbol is defined with
the value 1, then equality is tested.

Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Cc: Philippe De Muyter <phdm@macq.eu>
Cc: linux-m68k@lists.linux-m68k.org
Cc: Alistair Francis <alistai@xilinx.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: uclinux-h8-devel@lists.sourceforge.jp
2016-05-28 15:48:31 -04:00
George Spelvin
2a18da7a9c fs/namei.c: Improve dcache hash function
Patch 0fed3ac866 improved the hash mixing, but the function is slower
than necessary; there's a 7-instruction dependency chain (10 on x86)
each loop iteration.

Word-at-a-time access is a very tight loop (which is good, because
link_path_walk() is one of the hottest code paths in the entire kernel),
and the hash mixing function must not have a longer latency to avoid
slowing it down.

There do not appear to be any published fast hash functions that:
1) Operate on the input a word at a time, and
2) Don't need to know the length of the input beforehand, and
3) Have a single iterated mixing function, not needing conditional
   branches or unrolling to distinguish different loop iterations.

One of the algorithms which comes closest is Yann Collet's xxHash, but
that's two dependent multiplies per word, which is too much.

The key insights in this design are:

1) Barring expensive ops like multiplies, to diffuse one input bit
   across 64 bits of hash state takes at least log2(64) = 6 sequentially
   dependent instructions.  That is more cycles than we'd like.
2) An operation like "hash ^= hash << 13" requires a second temporary
   register anyway, and on a 2-operand machine like x86, it's three
   instructions.
3) A better use of a second register is to hold a two-word hash state.
   With careful design, no temporaries are needed at all, so it doesn't
   increase register pressure.  And this gets rid of register copying
   on 2-operand machines, so the code is smaller and faster.
4) Using two words of state weakens the requirement for one-round mixing;
   we now have two rounds of mixing before cancellation is possible.
5) A two-word hash state also allows operations on both halves to be
   done in parallel, so on a superscalar processor we get more mixing
   in fewer cycles.

I ended up using a mixing function inspired by the ChaCha and Speck
round functions.  It is 6 simple instructions and 3 cycles per iteration
(assuming multiply by 9 can be done by an "lea" instruction):

		x ^= *input++;
	y ^= x;	x = ROL(x, K1);
	x += y;	y = ROL(y, K2);
	y *= 9;

Not only is this reversible, two consecutive rounds are reversible:
if you are given the initial and final states, but not the intermediate
state, it is possible to compute both input words.  This means that at
least 3 words of input are required to create a collision.

(It also has the property, used by hash_name() to avoid a branch, that
it hashes all-zero to all-zero.)

The rotate constants K1 and K2 were found by experiment.  The search took
a sample of random initial states (I used 1023) and considered the effect
of flipping each of the 64 input bits on each of the 128 output bits two
rounds later.  Each of the 8192 pairs can be considered a biased coin, and
adding up the Shannon entropy of all of them produces a score.

The best-scoring shifts also did well in other tests (flipping bits in y,
trying 3 or 4 rounds of mixing, flipping all 64*63/2 pairs of input bits),
so the choice was made with the additional constraint that the sum of the
shifts is odd and not too close to the word size.

The final state is then folded into a 32-bit hash value by a less carefully
optimized multiply-based scheme.  This also has to be fast, as pathname
components tend to be short (the most common case is one iteration!), but
there's some room for latency, as there is a fair bit of intervening logic
before the hash value is used for anything.

(Performance verified with "bonnie++ -s 0 -n 1536:-2" on tmpfs.  I need
a better benchmark; the numbers seem to show a slight dip in performance
between 4.6.0 and this patch, but they're too noisy to quote.)

Special thanks to Bruce fields for diligent testing which uncovered a
nasty fencepost error in an earlier version of this patch.

[checkpatch.pl formatting complaints noted and respectfully disagreed with.]

Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Tested-by: J. Bruce Fields <bfields@redhat.com>
2016-05-28 15:45:29 -04:00
George Spelvin
fcfd2fbf22 fs/namei.c: Add hashlen_string() function
We'd like to make more use of the highly-optimized dcache hash functions
throughout the kernel, rather than have every subsystem create its own,
and a function that hashes basic null-terminated strings is required
for that.

(The name is to emphasize that it returns both hash and length.)

It's actually useful in the dcache itself, specifically d_alloc_name().
Other uses in the next patch.

full_name_hash() is also tweaked to make it more generally useful:
1) Take a "char *" rather than "unsigned char *" argument, to
   be consistent with hash_name().
2) Handle zero-length inputs.  If we want more callers, we don't want
   to make them worry about corner cases.

Signed-off-by: George Spelvin <linux@sciencehorizons.net>
2016-05-28 15:42:50 -04:00
Linus Torvalds
0b9210c9c8 xfs: update for 4.7-rc1
Changes in this update:
 o fixes for mount line parsing, sparse warnings, read-only compat
   feature remount behaviour
 o allow fast path symlink lookups for inline symlinks.
 o attribute listing cleanups
 o writeback goes direct to bios rather than indirecting through
   bufferheads
 o transaction allocation cleanup
 o optimised kmem_realloc
 o added configurable error handling for metadata write errors,
   changed default error handling behaviour from "retry forever" to
   "retry until unmount then fail"
 o fixed several inode cluster writeback lookup vs reclaim race
   conditions
 o fixed inode cluster writeback checking wrong inode after lookup
 o fixed bugs where struct xfs_inode freeing wasn't actually RCU safe
 o cleaned up inode reclaim tagging
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 
 iQIcBAABAgAGBQJXRo8LAAoJEK3oKUf0dfodxLgP+wQMd46i/nCncr6jMcdoVXfL
 rE6cL1LJWWVOWzax/bmdlV1VNXqqW7n0ABAVMqikzqSEd+fBQe/HOkdBeVUywu7o
 bmqgNxuofMqHaiYhiTvUijHLHWLFxIgd/jNT7L5oGRzZdmP260VGf3EPipN7aA9U
 Y3KVhFQCqohpeIUeSV4Z/eIDdHN5LyUI1s+7zMLquHKCWyO4aO4GBX8YlyXdRRVe
 cwCZb4TBryS0PBCIra31MZ5wBRwLx8PBXqcNsnTQSR5Uu+WeuwxofXz5q3kdmNOU
 XGTWiabQbcvaC4twrzqnErHEX41PAs43tWxsI/qJH49QIFdfOYM+t8ERhEa2Q3DW
 Ihl+Q/2qiOuZZterG/t5MrxhybrmQhEFVJT6Ib8b/CnwpRm+K8kWTead1YJL8Xzd
 F9k8e57BCgTbDA7jWxWDbp7eQ1/4KglBD4sefFPpsuFgO882mmo5GmymALGjmitw
 JH1v3HL3PeTkQoHfcay8ZM/zNjX643CXHwCWYEOAgD+e77TPiOs/cHLZaXbrBkLK
 PpSJNfYiBe31eeSOEGsxivMapLpus+cHZyK3uR+XU+naJhjOdaBDTTo8RsAD9jS5
 C/dzxc4l7o+gYT+UjV5KtyfEeVwtGo5mtR9XozPbNDjNQor8Vo6NQMZXMXpFYDZI
 2XgzVNpkEf/74kexdEzV
 =0tYo
 -----END PGP SIGNATURE-----

Merge tag 'xfs-for-linus-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs

Pull xfs updates from Dave Chinner:
 "A pretty average collection of fixes, cleanups and improvements in
  this request.

  Summary:
   - fixes for mount line parsing, sparse warnings, read-only compat
     feature remount behaviour
   - allow fast path symlink lookups for inline symlinks.
   - attribute listing cleanups
   - writeback goes direct to bios rather than indirecting through
     bufferheads
   - transaction allocation cleanup
   - optimised kmem_realloc
   - added configurable error handling for metadata write errors,
     changed default error handling behaviour from "retry forever" to
     "retry until unmount then fail"
   - fixed several inode cluster writeback lookup vs reclaim race
     conditions
   - fixed inode cluster writeback checking wrong inode after lookup
   - fixed bugs where struct xfs_inode freeing wasn't actually RCU safe
   - cleaned up inode reclaim tagging"

* tag 'xfs-for-linus-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (39 commits)
  xfs: fix warning in xfs_finish_page_writeback for non-debug builds
  xfs: move reclaim tagging functions
  xfs: simplify inode reclaim tagging interfaces
  xfs: rename variables in xfs_iflush_cluster for clarity
  xfs: xfs_iflush_cluster has range issues
  xfs: mark reclaimed inodes invalid earlier
  xfs: xfs_inode_free() isn't RCU safe
  xfs: optimise xfs_iext_destroy
  xfs: skip stale inodes in xfs_iflush_cluster
  xfs: fix inode validity check in xfs_iflush_cluster
  xfs: xfs_iflush_cluster fails to abort on error
  xfs: remove xfs_fs_evict_inode()
  xfs: add "fail at unmount" error handling configuration
  xfs: add configuration handlers for specific errors
  xfs: add configuration of error failure speed
  xfs: introduce table-based init for error behaviors
  xfs: add configurable error support to metadata buffers
  xfs: introduce metadata IO error class
  xfs: configurable error behavior via sysfs
  xfs: buffer ->bi_end_io function requires irq-safe lock
  ...
2016-05-26 10:13:40 -07:00
Linus Torvalds
f4f27d0028 Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull security subsystem updates from James Morris:
 "Highlights:

   - A new LSM, "LoadPin", from Kees Cook is added, which allows forcing
     of modules and firmware to be loaded from a specific device (this
     is from ChromeOS, where the device as a whole is verified
     cryptographically via dm-verity).

     This is disabled by default but can be configured to be enabled by
     default (don't do this if you don't know what you're doing).

   - Keys: allow authentication data to be stored in an asymmetric key.
     Lots of general fixes and updates.

   - SELinux: add restrictions for loading of kernel modules via
     finit_module().  Distinguish non-init user namespace capability
     checks.  Apply execstack check on thread stacks"

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (48 commits)
  LSM: LoadPin: provide enablement CONFIG
  Yama: use atomic allocations when reporting
  seccomp: Fix comment typo
  ima: add support for creating files using the mknodat syscall
  ima: fix ima_inode_post_setattr
  vfs: forbid write access when reading a file into memory
  fs: fix over-zealous use of "const"
  selinux: apply execstack check on thread stacks
  selinux: distinguish non-init user namespace capability checks
  LSM: LoadPin for kernel file loading restrictions
  fs: define a string representation of the kernel_read_file_id enumeration
  Yama: consolidate error reporting
  string_helpers: add kstrdup_quotable_file
  string_helpers: add kstrdup_quotable_cmdline
  string_helpers: add kstrdup_quotable
  selinux: check ss_initialized before revalidating an inode label
  selinux: delay inode label lookup as long as possible
  selinux: don't revalidate an inode's label when explicitly setting it
  selinux: Change bool variable name to index.
  KEYS: Add KEYCTL_DH_COMPUTE command
  ...
2016-05-19 09:21:36 -07:00
Linus Torvalds
c52b76185b Merge branch 'work.const-path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull 'struct path' constification update from Al Viro:
 "'struct path' is passed by reference to a bunch of Linux security
  methods; in theory, there's nothing to stop them from modifying the
  damn thing and LSM community being what it is, sooner or later some
  enterprising soul is going to decide that it's a good idea.

  Let's remove the temptation and constify all of those..."

* 'work.const-path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  constify ima_d_path()
  constify security_sb_pivotroot()
  constify security_path_chroot()
  constify security_path_{link,rename}
  apparmor: remove useless checks for NULL ->mnt
  constify security_path_{mkdir,mknod,symlink}
  constify security_path_{unlink,rmdir}
  apparmor: constify common_perm_...()
  apparmor: constify aa_path_link()
  apparmor: new helper - common_path_perm()
  constify chmod_common/security_path_chmod
  constify security_sb_mount()
  constify chown_common/security_path_chown
  tomoyo: constify assorted struct path *
  apparmor_path_truncate(): path->mnt is never NULL
  constify vfs_truncate()
  constify security_path_truncate()
  [apparmor] constify struct path * in a bunch of helpers
2016-05-17 14:41:03 -07:00
Linus Torvalds
7f427d3a60 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull parallel filesystem directory handling update from Al Viro.

This is the main parallel directory work by Al that makes the vfs layer
able to do lookup and readdir in parallel within a single directory.
That's a big change, since this used to be all protected by the
directory inode mutex.

The inode mutex is replaced by an rwsem, and serialization of lookups of
a single name is done by a "in-progress" dentry marker.

The series begins with xattr cleanups, and then ends with switching
filesystems over to actually doing the readdir in parallel (switching to
the "iterate_shared()" that only takes the read lock).

A more detailed explanation of the process from Al Viro:
 "The xattr work starts with some acl fixes, then switches ->getxattr to
  passing inode and dentry separately.  This is the point where the
  things start to get tricky - that got merged into the very beginning
  of the -rc3-based #work.lookups, to allow untangling the
  security_d_instantiate() mess.  The xattr work itself proceeds to
  switch a lot of filesystems to generic_...xattr(); no complications
  there.

  After that initial xattr work, the series then does the following:

   - untangle security_d_instantiate()

   - convert a bunch of open-coded lookup_one_len_unlocked() to calls of
     that thing; one such place (in overlayfs) actually yields a trivial
     conflict with overlayfs fixes later in the cycle - overlayfs ended
     up switching to a variant of lookup_one_len_unlocked() sans the
     permission checks.  I would've dropped that commit (it gets
     overridden on merge from #ovl-fixes in #for-next; proper resolution
     is to use the variant in mainline fs/overlayfs/super.c), but I
     didn't want to rebase the damn thing - it was fairly late in the
     cycle...

   - some filesystems had managed to depend on lookup/lookup exclusion
     for *fs-internal* data structures in a way that would break if we
     relaxed the VFS exclusion.  Fixing hadn't been hard, fortunately.

   - core of that series - parallel lookup machinery, replacing
     ->i_mutex with rwsem, making lookup_slow() take it only shared.  At
     that point lookups happen in parallel; lookups on the same name
     wait for the in-progress one to be done with that dentry.

     Surprisingly little code, at that - almost all of it is in
     fs/dcache.c, with fs/namei.c changes limited to lookup_slow() -
     making it use the new primitive and actually switching to locking
     shared.

   - parallel readdir stuff - first of all, we provide the exclusion on
     per-struct file basis, same as we do for read() vs lseek() for
     regular files.  That takes care of most of the needed exclusion in
     readdir/readdir; however, these guys are trickier than lookups, so
     I went for switching them one-by-one.  To do that, a new method
     '->iterate_shared()' is added and filesystems are switched to it
     as they are either confirmed to be OK with shared lock on directory
     or fixed to be OK with that.  I hope to kill the original method
     come next cycle (almost all in-tree filesystems are switched
     already), but it's still not quite finished.

   - several filesystems get switched to parallel readdir.  The
     interesting part here is dealing with dcache preseeding by readdir;
     that needs minor adjustment to be safe with directory locked only
     shared.

     Most of the filesystems doing that got switched to in those
     commits.  Important exception: NFS.  Turns out that NFS folks, with
     their, er, insistence on VFS getting the fuck out of the way of the
     Smart Filesystem Code That Knows How And What To Lock(tm) have
     grown the locking of their own.  They had their own homegrown
     rwsem, with lookup/readdir/atomic_open being *writers* (sillyunlink
     is the reader there).  Of course, with VFS getting the fuck out of
     the way, as requested, the actual smarts of the smart filesystem
     code etc. had become exposed...

   - do_last/lookup_open/atomic_open cleanups.  As the result, open()
     without O_CREAT locks the directory only shared.  Including the
     ->atomic_open() case.  Backmerge from #for-linus in the middle of
     that - atomic_open() fix got brought in.

   - then comes NFS switch to saner (VFS-based ;-) locking, killing the
     homegrown "lookup and readdir are writers" kinda-sorta rwsem.  All
     exclusion for sillyunlink/lookup is done by the parallel lookups
     mechanism.  Exclusion between sillyunlink and rmdir is a real rwsem
     now - rmdir being the writer.

     Result: NFS lookups/readdirs/O_CREAT-less opens happen in parallel
     now.

   - the rest of the series consists of switching a lot of filesystems
     to parallel readdir; in a lot of cases ->llseek() gets simplified
     as well.  One backmerge in there (again, #for-linus - rockridge
     fix)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (74 commits)
  ext4: switch to ->iterate_shared()
  hfs: switch to ->iterate_shared()
  hfsplus: switch to ->iterate_shared()
  hostfs: switch to ->iterate_shared()
  hpfs: switch to ->iterate_shared()
  hpfs: handle allocation failures in hpfs_add_pos()
  gfs2: switch to ->iterate_shared()
  f2fs: switch to ->iterate_shared()
  afs: switch to ->iterate_shared()
  befs: switch to ->iterate_shared()
  befs: constify stuff a bit
  isofs: switch to ->iterate_shared()
  get_acorn_filename(): deobfuscate a bit
  btrfs: switch to ->iterate_shared()
  logfs: no need to lock directory in lseek
  switch ecryptfs to ->iterate_shared
  9p: switch to ->iterate_shared()
  fat: switch to ->iterate_shared()
  romfs, squashfs: switch to ->iterate_shared()
  more trivial ->iterate_shared conversions
  ...
2016-05-17 11:01:31 -07:00
Al Viro
0e0162bb8c Merge branch 'ovl-fixes' into for-linus
Backmerge to resolve a conflict in ovl_lookup_real();
"ovl_lookup_real(): use lookup_one_len_unlocked()" instead,
but it was too late in the cycle to rebase.
2016-05-17 02:17:59 -04:00
George Spelvin
0fed3ac866 namei: Improve hash mixing if CONFIG_DCACHE_WORD_ACCESS
The hash mixing between adding the next 64 bits of name
was just a bit weak.

Replaced with a still very fast but slightly more effective
mixing function.

Signed-off-by: George Spelvin <linux@horizon.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-16 11:35:08 -07:00
Al Viro
e4d35be584 Merge branch 'ovl-fixes' into for-linus 2016-05-11 00:00:29 -04:00
Miklos Szeredi
3c9fe8cdff vfs: add lookup_hash() helper
Overlayfs needs lookup without inode_permission() and already has the name
hash (in form of dentry->d_name on overlayfs dentry).  It also doesn't
support filesystems with d_op->d_hash() so basically it only needs
the actual hashed lookup from lookup_one_len_unlocked()

So add a new helper that does unlocked lookup of a hashed name.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-05-10 23:56:28 -04:00
Miklos Szeredi
9409e22acd vfs: rename: check backing inode being equal
If a file is renamed to a hardlink of itself POSIX specifies that rename(2)
should do nothing and return success.

This condition is checked in vfs_rename().  However it won't detect hard
links on overlayfs where these are given separate inodes on the overlayfs
layer.

Overlayfs itself detects this condition and returns success without doing
anything, but then vfs_rename() will proceed as if this was a successful
rename (detach_mounts(), d_move()).

The correct thing to do is to detect this condition before even calling
into overlayfs.  This patch does this by calling vfs_select_inode() to get
the underlying inodes.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Cc: <stable@vger.kernel.org> # v4.2+
2016-05-10 23:55:43 -04:00
Al Viro
9cf843e3f4 lookup_open(): lock the parent shared unless O_CREAT is given
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:51:17 -04:00
Al Viro
6fbd07146d lookup_open(): put the dentry fed to ->lookup() or ->atomic_open() into in-lookup hash
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:51:16 -04:00
Al Viro
12fa5e2404 lookup_open(): expand the call of real_lookup()
... and lose the duplicate IS_DEADDIR() - we'd already checked that.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:51:16 -04:00
Al Viro
384f26e28f atomic_open(): reorder and clean up a bit
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:51:15 -04:00
Al Viro
1643b43fbd lookup_open(): lift the "fallback to !O_CREAT" logics from atomic_open()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:51:15 -04:00
Al Viro
b3d58eaffb atomic_open(): be paranoid about may_open() return value
It should never return positives; however, with Linux S&M crowd
involved, no bogosity is impossible.  Results would be unpleasant...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:51:14 -04:00
Al Viro
0fb1ea0933 atomic_open(): delay open_to_namei_flags() until the method call
nobody else needs that transformation.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:51:14 -04:00
Al Viro
fe9ec8291f do_last(): take fput() on error after opening to out:
make it conditional on *opened & FILE_OPENED; in addition to getting
rid of exit_fput: thing, it simplifies atomic_open() cleanup on
may_open() failure.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:51:13 -04:00
Al Viro
47f9dbd387 do_last(): get rid of duplicate ELOOP check
may_open() will catch it

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:51:13 -04:00
Al Viro
55db2fd936 atomic_open(): massage the create_error logics a bit
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:51:12 -04:00
Al Viro
9d0728e16e atomic_open(): consolidate "overridden ENOENT" in open-yourself cases
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:51:12 -04:00
Al Viro
5249e411b4 atomic_open(): don't bother with EEXIST check - it's done in do_last()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:51:11 -04:00
Al Viro
df889b3631 Merge branch 'for-linus' into work.lookups 2016-05-02 19:49:46 -04:00
Al Viro
ce8644fcad lookup_open(): expand the call of vfs_create()
Lift IS_DEADDIR handling up into the part common with atomic_open(),
remove it from the latter.  Collapse permission checks into the
call of may_o_create(), getting it closer to atomic_open() case.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:49:33 -04:00
Al Viro
6ac087099e path_openat(): take O_PATH handling out of do_last()
do_last() and lookup_open() simpler that way and so does O_PATH
itself.  As it bloody well should: we find what the pathname
resolves to, same way as in stat() et.al. and associate it with
FMODE_PATH struct file.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:49:33 -04:00
Al Viro
9902af79c0 parallel lookups: actual switch to rwsem
ta-da!

The main issue is the lack of down_write_killable(), so the places
like readdir.c switched to plain inode_lock(); once killable
variants of rwsem primitives appear, that'll be dealt with.

lockdep side also might need more work

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:49:28 -04:00
Al Viro
d9171b9345 parallel lookups machinery, part 4 (and last)
If we *do* run into an in-lookup match, we need to wait for it to
cease being in-lookup.  Fortunately, we do have unused space in
in-lookup dentries - d_lru is never looked at until it stops being
in-lookup.

So we can stash a pointer to wait_queue_head from stack frame of
the caller of ->lookup().  Some precautions are needed while
waiting, but it's not that hard - we do hold a reference to dentry
we are waiting for, so it can't go away.  If it's found to be
in-lookup the wait_queue_head is still alive and will remain so
at least while ->d_lock is held.  Moreover, the condition we
are waiting for becomes true at the same point where everything
on that wq gets woken up, so we can just add ourselves to the
queue once.

d_alloc_parallel() gets a pointer to wait_queue_head_t from its
caller; lookup_slow() adjusted, d_add_ci() taught to use
d_alloc_parallel() if the dentry passed to it happens to be
in-lookup one (i.e. if it's been called from the parallel lookup).

That's pretty much it - all that remains is to switch ->i_mutex
to rwsem and have lookup_slow() take it shared.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:49:27 -04:00
Al Viro
94bdd655ca parallel lookups machinery, part 3
We will need to be able to check if there is an in-lookup
dentry with matching parent/name.  Right now it's impossible,
but as soon as start locking directories shared such beasts
will appear.

Add a secondary hash for locating those.  Hash chains go through
the same space where d_alias will be once it's not in-lookup anymore.
Search is done under the same bitlock we use for modifications -
with the primary hash we can rely on d_rehash() into the wrong
chain being the worst that could happen, but here the pointers are
buggered once it's removed from the chain.  On the other hand,
the chains are not going to be long and normally we'll end up
adding to the chain anyway.  That allows us to avoid bothering with
->d_lock when doing the comparisons - everything is stable until
removed from chain.

New helper: d_alloc_parallel().  Right now it allocates, verifies
that no hashed and in-lookup matches exist and adds to in-lookup
hash.

Returns ERR_PTR() for error, hashed match (in the unlikely case it's
been found) or new dentry.  In-lookup matches trigger BUG() for
now; that will change in the next commit when we introduce waiting
for ongoing lookup to finish.  Note that in-lookup matches won't be
possible until we actually go for shared locking.

lookup_slow() switched to use of d_alloc_parallel().

Again, these commits are separated only for making it easier to
review.  All this machinery will start doing something useful only
when we go for shared locking; it's just that the combination is
too large for my taste.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:49:27 -04:00
Al Viro
85c7f81041 beginning of transition to parallel lookups - marking in-lookup dentries
marked as such when (would be) parallel lookup is about to pass them
to actual ->lookup(); unmarked when
	* __d_add() is about to make it hashed, positive or not.
	* __d_move() (from d_splice_alias(), directly or via
__d_unalias()) puts a preexisting dentry in its place
	* in caller of ->lookup() if it has escaped all of the
above.  Bug (WARN_ON, actually) if it reaches the final dput()
or d_instantiate() while still marked such.

As the result, we are guaranteed that for as long as the flag is
set, dentry will
	* remain negative unhashed with positive refcount
	* never have its ->d_alias looked at
	* never have its ->d_lru looked at
	* never have its ->d_parent and ->d_name changed

Right now we have at most one such for any given parent directory.
With parallel lookups that restriction will weaken to
	* only exist when parent is locked shared
	* at most one with given (parent,name) pair (comparison of
names is according to ->d_compare())
	* only exist when there's no hashed dentry with the same
(parent,name)

Transition will take the next several commits; unfortunately, we'll
only be able to switch to rwsem at the end of this series.  The
reason for not making it a single patch is to simplify review.

New primitives: d_in_lookup() (a predicate checking if dentry is in
the in-lookup state) and d_lookup_done() (tells the system that
we are done with lookup and if it's still marked as in-lookup, it
should cease to be such).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:47:51 -04:00
Al Viro
1936386ea9 lookup_slow(): bugger off on IS_DEADDIR() from the very beginning
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02 19:47:26 -04:00
Al Viro
84695ffee7 Merge getxattr prototype change into work.lookups
The rest of work.xattr stuff isn't needed for this branch
2016-05-02 19:45:47 -04:00
Mimi Zohar
05d1a717ec ima: add support for creating files using the mknodat syscall
Commit 3034a14 "ima: pass 'opened' flag to identify newly created files"
stopped identifying empty files as new files.  However new empty files
can be created using the mknodat syscall.  On systems with IMA-appraisal
enabled, these empty files are not labeled with security.ima extended
attributes properly, preventing them from subsequently being opened in
order to write the file data contents.  This patch defines a new hook
named ima_post_path_mknod() to mark these empty files, created using
mknodat, as new in order to allow the file data contents to be written.

In addition, files with security.ima xattrs containing a file signature
are considered "immutable" and can not be modified.  The file contents
need to be written, before signing the file.  This patch relaxes this
requirement for new files, allowing the file signature to be written
before the file contents.

Changelog:
- defer identifying files with signatures stored as security.ima
  (based on Dmitry Rozhkov's comments)
- removing tests (eg. dentry, dentry->d_inode, inode->i_size == 0)
  (based on Al's review)

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Al Viro <<viro@zeniv.linux.org.uk>
Tested-by: Dmitry Rozhkov <dmitry.rozhkov@linux.intel.com>
2016-05-01 09:23:52 -04:00
Al Viro
10c64cea04 atomic_open(): fix the handling of create_error
* if we have a hashed negative dentry and either CREAT|EXCL on
r/o filesystem, or CREAT|TRUNC on r/o filesystem, or CREAT|EXCL
with failing may_o_create(), we should fail with EROFS or the
error may_o_create() has returned, but not ENOENT.  Which is what
the current code ends up returning.

* if we have CREAT|TRUNC hitting a regular file on a read-only
filesystem, we can't fail with EROFS here.  At the very least,
not until we'd done follow_managed() - we might have a writable
file (or a device, for that matter) bound on top of that one.
Moreover, the code downstream will see that O_TRUNC and attempt
to grab the write access (*after* following possible mount), so
if we really should fail with EROFS, it will happen.  No need
to do that inside atomic_open().

The real logics is much simpler than what the current code is
trying to do - if we decided to go for simple lookup, ended
up with a negative dentry *and* had create_error set, fail with
create_error.  No matter whether we'd got that negative dentry
from lookup_real() or had found it in dcache.

Cc: stable@vger.kernel.org # v3.6+
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-04-30 16:40:52 -04:00
Al Viro
fc64005c93 don't bother with ->d_inode->i_sb - it's always equal to ->d_sb
... and neither can ever be NULL

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-04-10 17:11:51 -04:00