Commit Graph

1320 Commits

Author SHA1 Message Date
NeilBrown
7d1cf5e624
vfs: generate FS_CREATE before FS_OPEN when ->atomic_open used.
When a file is opened and created with open(..., O_CREAT) we get
both the CREATE and OPEN fsnotify events and would expect them in that
order.   For most filesystems we get them in that order because
open_last_lookups() calls fsnofify_create() and then do_open() (from
path_openat()) calls vfs_open()->do_dentry_open() which calls
fsnotify_open().

However when ->atomic_open is used, the
   do_dentry_open() -> fsnotify_open()
call happens from finish_open() which is called from the ->atomic_open
handler in lookup_open() which is called *before* open_last_lookups()
calls fsnotify_create.  So we get the "open" notification before
"create" - which is backwards.  ltp testcase inotify02 tests this and
reports the inconsistency.

This patch lifts the fsnotify_open() call out of do_dentry_open() and
places it higher up the call stack.  There are three callers of
do_dentry_open().

For vfs_open() and kernel_file_open() the fsnotify_open() is placed
directly in that caller so there should be no behavioural change.

For finish_open() there are two cases:
 - finish_open is used in ->atomic_open handlers.  For these we add a
   call to fsnotify_open() at open_last_lookups() if FMODE_OPENED is
   set - which means do_dentry_open() has been called.
 - finish_open is used in ->tmpfile() handlers.  For these a similar
   call to fsnotify_open() is added to vfs_tmpfile()

With this patch NFSv3 is restored to its previous behaviour (before
->atomic_open support was added) of generating CREATE notifications
before OPEN, and NFSv4 now has that same correct ordering that is has
not had before.  I haven't tested other filesystems.

Fixes: 7c6c5249f0 ("NFS: add atomic_open for NFSv3 to handle O_TRUNC correctly.")
Reported-by: James Clark <james.clark@arm.com>
Closes: https://lore.kernel.org/all/01c3bf2e-eb1f-4b7f-a54f-d2a05dd3d8c8@arm.com
Signed-off-by: NeilBrown <neilb@suse.de>
Link: https://lore.kernel.org/r/171817619547.14261.975798725161704336@noble.neil.brown.name
Fixes: 7b8c9d7bb4 ("fsnotify: move fsnotify_open() hook into do_dentry_open()")
Tested-by: James Clark <james.clark@arm.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20240617162303.1596-2-jack@suse.cz
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-06-18 16:26:09 +02:00
Linus Torvalds
0e22bedd75 overlayfs update for 6.10
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQSQHSd0lITzzeNWNm3h3BK/laaZPAUCZk3w7AAKCRDh3BK/laaZ
 PFlfAQD7puZ3BowTZ6cTCJ0Zg6U9wNMszlYHl3WyDnYDicaiVgD9HTqlv1pbNoFh
 e5hyXI4vgaMZkYfpET0zBhVkirSKEg4=
 =1vRI
 -----END PGP SIGNATURE-----

Merge tag 'ovl-update-6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs

Pull overlayfs updates from Miklos Szeredi:

 - Add tmpfile support

 - Clean up include

* tag 'ovl-update-6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs:
  ovl: remove duplicate included header
  ovl: remove upper umask handling from ovl_create_upper()
  ovl: implement tmpfile
2024-05-22 09:23:18 -07:00
Linus Torvalds
1b0aabcc9a vfs-6.10.misc
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCZj3HuwAKCRCRxhvAZXjc
 orYvAQCZOr68uJaEaXAArYTdnMdQ6HIzG+FVlwrqtrhz0BV07wEAqgmtSR9XKh+L
 0+DNepg4R8PZOHH371eSSsLNRCUCkAs=
 =SVsU
 -----END PGP SIGNATURE-----

Merge tag 'vfs-6.10.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull misc vfs updates from Christian Brauner:
 "This contains the usual miscellaneous features, cleanups, and fixes
  for vfs and individual fses.

  Features:

   - Free up FMODE_* bits. I've freed up bits 6, 7, 8, and 24. That
     means we now have six free FMODE_* bits in total (but bit #6
     already got used for FMODE_WRITE_RESTRICTED)

   - Add FOP_HUGE_PAGES flag (follow-up to FMODE_* cleanup)

   - Add fd_raw cleanup class so we can make use of automatic cleanup
     provided by CLASS(fd_raw, f)(fd) for O_PATH fds as well

   - Optimize seq_puts()

   - Simplify __seq_puts()

   - Add new anon_inode_getfile_fmode() api to allow specifying f_mode
     instead of open-coding it in multiple places

   - Annotate struct file_handle with __counted_by() and use
     struct_size()

   - Warn in get_file() whether f_count resurrection from zero is
     attempted (epoll/drm discussion)

   - Folio-sophize aio

   - Export the subvolume id in statx() for both btrfs and bcachefs

   - Relax linkat(AT_EMPTY_PATH) requirements

   - Add F_DUPFD_QUERY fcntl() allowing to compare two file descriptors
     for dup*() equality replacing kcmp()

  Cleanups:

   - Compile out swapfile inode checks when swap isn't enabled

   - Use (1 << n) notation for FMODE_* bitshifts for clarity

   - Remove redundant variable assignment in fs/direct-io

   - Cleanup uses of strncpy in orangefs

   - Speed up and cleanup writeback

   - Move fsparam_string_empty() helper into header since it's currently
     open-coded in multiple places

   - Add kernel-doc comments to proc_create_net_data_write()

   - Don't needlessly read dentry->d_flags twice

  Fixes:

   - Fix out-of-range warning in nilfs2

   - Fix ecryptfs overflow due to wrong encryption packet size
     calculation

   - Fix overly long line in xfs file_operations (follow-up to FMODE_*
     cleanup)

   - Don't raise FOP_BUFFER_{R,W}ASYNC for directories in xfs (follow-up
     to FMODE_* cleanup)

   - Don't call xfs_file_open from xfs_dir_open (follow-up to FMODE_*
     cleanup)

   - Fix stable offset api to prevent endless loops

   - Fix afs file server rotations

   - Prevent xattr node from overflowing the eraseblock in jffs2

   - Move fdinfo PTRACE_MODE_READ procfs check into the .permission()
     operation instead of .open() operation since this caused userspace
     regressions"

* tag 'vfs-6.10.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (39 commits)
  afs: Fix fileserver rotation getting stuck
  selftests: add F_DUPDFD_QUERY selftests
  fcntl: add F_DUPFD_QUERY fcntl()
  file: add fd_raw cleanup class
  fs: WARN when f_count resurrection is attempted
  seq_file: Simplify __seq_puts()
  seq_file: Optimize seq_puts()
  proc: Move fdinfo PTRACE_MODE_READ check into the inode .permission operation
  fs: Create anon_inode_getfile_fmode()
  xfs: don't call xfs_file_open from xfs_dir_open
  xfs: drop fop_flags for directories
  xfs: fix overly long line in the file_operations
  shmem: Fix shmem_rename2()
  libfs: Add simple_offset_rename() API
  libfs: Fix simple_offset_rename_exchange()
  jffs2: prevent xattr node from overflowing the eraseblock
  vfs, swap: compile out IS_SWAPFILE() on swapless configs
  vfs: relax linkat() AT_EMPTY_PATH - aka flink() - requirements
  fs/direct-io: remove redundant assignment to variable retval
  fs/dcache: Re-use value stored to dentry->d_flags instead of re-reading
  ...
2024-05-13 11:40:06 -07:00
Miklos Szeredi
9a87907de3 ovl: implement tmpfile
Combine inode creation with opening a file.

There are six separate objects that are being set up: the backing inode,
dentry and file, and the overlay inode, dentry and file.  Cleanup in case
of an error is a bit of a challenge and is difficult to test, so careful
review is needed.

All tmpfile testcases except generic/509 now run/pass, and no regressions
are observed with full xfstests.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
2024-05-02 20:35:57 +02:00
Linus Torvalds
42bd2af595
vfs: relax linkat() AT_EMPTY_PATH - aka flink() - requirements
"The definition of insanity is doing the same thing over and over
    again and expecting different results”

We've tried to do this before, most recently with commit bb2314b479
("fs: Allow unprivileged linkat(..., AT_EMPTY_PATH) aka flink") about a
decade ago.

But the effort goes back even further than that, eg this thread back
from 1998 that is so old that we don't even have it archived in lore:

    https://lkml.org/lkml/1998/3/10/108

which also points out some of the reasons why it's dangerous.

Or, how about then in 2003:

    https://lkml.org/lkml/2003/4/6/112

where we went through some of the same arguments, just wirh different
people involved.

In particular, having access to a file descriptor does not necessarily
mean that you have access to the path that was used for lookup, and
there may be very good reasons why you absolutely must not have access
to a path to said file.

For example, if we were passed a file descriptor from the outside into
some limited environment (think chroot, but also user namespaces etc) a
'flink()' system call could now make that file visible inside a context
where it's not supposed to be visible.

In the process the user may also be able to re-open it with permissions
that the original file descriptor did not have (eg a read-only file
descriptor may be associated with an underlying file that is writable).

Another variation on this is if somebody else (typically root) opens a
file in a directory that is not accessible to others, and passes the
file descriptor on as a read-only file.  Again, the access to the file
descriptor does not imply that you should have access to a path to the
file in the filesystem.

So while we have tried this several times in the past, it never works.

The last time we did this, that commit bb2314b479 quickly got reverted
again in commit f0cc6ffb8c (Revert "fs: Allow unprivileged linkat(...,
AT_EMPTY_PATH) aka flink"), with a note saying "We may re-do this once
the whole discussion about the interface is done".

Well, the discussion is long done, and didn't come to any resolution.
There's no question that 'flink()' would be a useful operation, but it's
a dangerous one.

However, it does turn out that since 2008 (commit d76b0d9b2d: "CRED:
Use creds in file structs") we have had a fairly straightforward way to
check whether the file descriptor was opened by the same credentials as
the credentials of the flink().

That allows the most common patterns that people want to use, which tend
to be to either open the source carefully (ie using the openat2()
RESOLVE_xyz flags, and/or checking ownership with fstat() before
linking), or to use O_TMPFILE and fill in the file contents before it's
exposed to the world with linkat().

But it also means that if the file descriptor was opened by somebody
else, or we've gone through a credentials change since, the operation no
longer works (unless we have CAP_DAC_READ_SEARCH capabilities in the
opener's user namespace, as before).

Note that the credential equality check is done by using pointer
equality, which means that it's not enough that you have effectively the
same user - they have to be literally identical, since our credentials
are using copy-on-write semantics.

So you can't change your credentials to something else and try to change
it back to the same ones between the open() and the linkat().  This is
not meant to be some kind of generic permission check, this is literally
meant as a "the open and link calls are 'atomic' wrt user credentials"
check.

It also means that you can't just move things between namespaces,
because the credentials aren't just a list of uid's and gid's: they
includes the pointer to the user_ns that the capabilities are relative
to.

So let's try this one more time and see if maybe this approach ends up
being workable after all.

Cc: Andrew Lutomirski <luto@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240411001012.12513-1-torvalds@linux-foundation.org
[brauner: relax capability check to opener of the file]
Link: https://lore.kernel.org/all/20231113-undenkbar-gediegen-efde5f1c34bc@brauner
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-04-13 11:33:58 +02:00
Roberto Sassu
701b38995e security: Place security_path_post_mknod() where the original IMA call was
Commit 08abce60d6 ("security: Introduce path_post_mknod hook")
introduced security_path_post_mknod(), to replace the IMA-specific call
to ima_post_path_mknod().

For symmetry with security_path_mknod(), security_path_post_mknod() was
called after a successful mknod operation, for any file type, rather
than only for regular files at the time there was the IMA call.

However, as reported by VFS maintainers, successful mknod operation does
not mean that the dentry always has an inode attached to it (for
example, not for FIFOs on a SAMBA mount).

If that condition happens, the kernel crashes when
security_path_post_mknod() attempts to verify if the inode associated to
the dentry is private.

Move security_path_post_mknod() where the ima_post_path_mknod() call was,
which is obviously correct from IMA/EVM perspective. IMA/EVM are the only
in-kernel users, and only need to inspect regular files.

Reported-by: Steve French <smfrench@gmail.com>
Closes: https://lore.kernel.org/linux-kernel/CAH2r5msAVzxCUHHG8VKrMPUKQHmBpE6K9_vjhgDa1uAvwx4ppw@mail.gmail.com/
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Fixes: 08abce60d6 ("security: Introduce path_post_mknod hook")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-04-03 10:21:32 -07:00
Linus Torvalds
cc4a875cf3 lsm/stable-6.9 PR 20240312
-----BEGIN PGP SIGNATURE-----
 
 iQJIBAABCAAyFiEES0KozwfymdVUl37v6iDy2pc3iXMFAmXwt3cUHHBhdWxAcGF1
 bC1tb29yZS5jb20ACgkQ6iDy2pc3iXObOhAAqldn1nbYS/t1D/k/9ZN/PtSQetK4
 S58D8+gB59Sg0daWFaRhCwwShIbXS/6XzhqaVb3iAPptJs0YDFMbWLAW2d+dd69K
 /7C8diguHbuJdEnCJtFYQIVinavaYVRlyoQcO8uwTz8uvTgXPOhr2P9NcOApJXcR
 xqttuADVo/9Zn0O9/+GUPCH0ROL0SMnuUjwdVP3bpPHj9zEk8F1/A6chzTeSLJru
 Y4+cRrN/r0JTkvRqPdnF9LSvxK7mtAEaHkKGeLQbw0O5pv3r3w0EWMJvq+uonGU2
 WX0eR5VMfevkFMUdw8FKOTa+OZ0HJ2KKIb4sB4wDMgeGyov7Z6SxgvFeQiSyD3aB
 QnyfLDzeEuPfousxUd45dUDnsWNnSgFF+JAdi0LSzm5hMuLeQDozTsFmh0orQcX1
 L5A6VtAbSPP0ffl+tuPi48q3P3LlSjMP0B8W20NXFYhXukKXCgXVMr/dEvpwpu1m
 o1glviGIXeLQQSnX3lMWb7Ds2igmCtXPrqkdu2vpRhMp0od6n4R4jH73Aj5MeSQn
 n3sP73dg5sAaMjtI2NOisMeFUp09MMlOumCCM+AIplPXremm1kwgKRTIp0rKsLW9
 VoQPXa43LQc3hAgPrpGuE+4yBfaBUq7Z8I37IFER/2y4K8b9YkduW4kDh7OdRz+d
 iQ4Nnu2lR/+CCH0=
 =0mTM
 -----END PGP SIGNATURE-----

Merge tag 'lsm-pr-20240312' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

Pull lsm updates from Paul Moore:

 - Promote IMA/EVM to a proper LSM

   This is the bulk of the diffstat, and the source of all the changes
   in the VFS code. Prior to the start of the LSM stacking work it was
   important that IMA/EVM were separate from the rest of the LSMs,
   complete with their own hooks, infrastructure, etc. as it was the
   only way to enable IMA/EVM at the same time as a LSM.

   However, now that the bulk of the LSM infrastructure supports
   multiple simultaneous LSMs, we can simplify things greatly by
   bringing IMA/EVM into the LSM infrastructure as proper LSMs. This is
   something I've wanted to see happen for quite some time and Roberto
   was kind enough to put in the work to make it happen.

 - Use the LSM hook default values to simplify the call_int_hook() macro

   Previously the call_int_hook() macro required callers to supply a
   default return value, despite a default value being specified when
   the LSM hook was defined.

   This simplifies the macro by using the defined default return value
   which makes life easier for callers and should also reduce the number
   of return value bugs in the future (we've had a few pop up recently,
   hence this work).

 - Use the KMEM_CACHE() macro instead of kmem_cache_create()

   The guidance appears to be to use the KMEM_CACHE() macro when
   possible and there is no reason why we can't use the macro, so let's
   use it.

 - Fix a number of comment typos in the LSM hook comment blocks

   Not much to say here, we fixed some questionable grammar decisions in
   the LSM hook comment blocks.

* tag 'lsm-pr-20240312' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: (28 commits)
  cred: Use KMEM_CACHE() instead of kmem_cache_create()
  lsm: use default hook return value in call_int_hook()
  lsm: fix typos in security/security.c comment headers
  integrity: Remove LSM
  ima: Make it independent from 'integrity' LSM
  evm: Make it independent from 'integrity' LSM
  evm: Move to LSM infrastructure
  ima: Move IMA-Appraisal to LSM infrastructure
  ima: Move to LSM infrastructure
  integrity: Move integrity_kernel_module_request() to IMA
  security: Introduce key_post_create_or_update hook
  security: Introduce inode_post_remove_acl hook
  security: Introduce inode_post_set_acl hook
  security: Introduce inode_post_create_tmpfile hook
  security: Introduce path_post_mknod hook
  security: Introduce file_release hook
  security: Introduce file_post_open hook
  security: Introduce inode_post_removexattr hook
  security: Introduce inode_post_setattr hook
  security: Align inode_setattr hook definition with EVM
  ...
2024-03-12 20:03:34 -07:00
Linus Torvalds
216532e147 hardening updates for v6.9-rc1
- string.h and related header cleanups (Tanzir Hasan, Andy Shevchenko)
 
 - VMCI memcpy() usage and struct_size() cleanups (Vasiliy Kovalev, Harshit
   Mogalapalli)
 
 - selftests/powerpc: Fix load_unaligned_zeropad build failure (Michael
   Ellerman)
 
 - hardened Kconfig fragment updates (Marco Elver, Lukas Bulwahn)
 
 - Handle tail call optimization better in LKDTM (Douglas Anderson)
 
 - Use long form types in overflow.h (Andy Shevchenko)
 
 - Add flags param to string_get_size() (Andy Shevchenko)
 
 - Add Coccinelle script for potential struct_size() use (Jacob Keller)
 
 - Fix objtool corner case under KCFI (Josh Poimboeuf)
 
 - Drop 13 year old backward compat CAP_SYS_ADMIN check (Jingzi Meng)
 
 - Add str_plural() helper (Michal Wajdeczko, Kees Cook)
 
 - Ignore relocations in .notes section
 
 - Add comments to explain how __is_constexpr() works
 
 - Fix m68k stack alignment expectations in stackinit Kunit test
 
 - Convert string selftests to KUnit
 
 - Add KUnit tests for fortified string functions
 
 - Improve reporting during fortified string warnings
 
 - Allow non-type arg to type_max() and type_min()
 
 - Allow strscpy() to be called with only 2 arguments
 
 - Add binary mode to leaking_addresses scanner
 
 - Various small cleanups to leaking_addresses scanner
 
 - Adding wrapping_*() arithmetic helper
 
 - Annotate initial signed integer wrap-around in refcount_t
 
 - Add explicit UBSAN section to MAINTAINERS
 
 - Fix UBSAN self-test warnings
 
 - Simplify UBSAN build via removal of CONFIG_UBSAN_SANITIZE_ALL
 
 - Reintroduce UBSAN's signed overflow sanitizer
 -----BEGIN PGP SIGNATURE-----
 
 iQJKBAABCgA0FiEEpcP2jyKd1g9yPm4TiXL039xtwCYFAmXvm5kWHGtlZXNjb29r
 QGNocm9taXVtLm9yZwAKCRCJcvTf3G3AJiQqD/4mM6SWZpYHKlR1nEiqIyz7Hqr9
 g4oguuw6HIVNJXLyeBI5Hd43CTeHPA0e++EETqhUAt7HhErxfYJY+JB221nRYmu+
 zhhQ7N/xbTMV/Je7AR03kQjhiMm8LyEcM2X4BNrsAcoCieQzmO3g0zSp8ISzLUE0
 PEEmf1lOzMe3gK2KOFCPt5Hiz9sGWyN6at+BQubY18tQGtjEXYAQNXkpD5qhGn4a
 EF693r/17wmc8hvSsjf4AGaWy1k8crG0WfpMCZsaqftjj0BbvOC60IDyx4eFjpcy
 tGyAJKETq161AkCdNweIh2Q107fG3tm0fcvw2dv8Wt1eQCko6M8dUGCBinQs/thh
 TexjJFS/XbSz+IvxLqgU+C5qkOP23E0M9m1dbIbOFxJAya/5n16WOBlGr3ae2Wdq
 /+t8wVSJw3vZiku5emWdFYP1VsdIHUjVa5QizFaaRhzLGRwhxVV49SP4IQC/5oM5
 3MAgNOFTP6yRQn9Y9wP+SZs+SsfaIE7yfKa9zOi4S+Ve+LI2v4YFhh8NCRiLkeWZ
 R1dhp8Pgtuq76f/v0qUaWcuuVeGfJ37M31KOGIhi1sI/3sr7UMrngL8D1+F8UZMi
 zcLu+x4GtfUZCHl6znx1rNUBqE5S/5ndVhLpOqfCXKaQ+RAm7lkOJ3jXE2VhNkhp
 yVEmeSOLnlCaQjZvXQ==
 =OP+o
 -----END PGP SIGNATURE-----

Merge tag 'hardening-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull hardening updates from Kees Cook:
 "As is pretty normal for this tree, there are changes all over the
  place, especially for small fixes, selftest improvements, and improved
  macro usability.

  Some header changes ended up landing via this tree as they depended on
  the string header cleanups. Also, a notable set of changes is the work
  for the reintroduction of the UBSAN signed integer overflow sanitizer
  so that we can continue to make improvements on the compiler side to
  make this sanitizer a more viable future security hardening option.

  Summary:

   - string.h and related header cleanups (Tanzir Hasan, Andy
     Shevchenko)

   - VMCI memcpy() usage and struct_size() cleanups (Vasiliy Kovalev,
     Harshit Mogalapalli)

   - selftests/powerpc: Fix load_unaligned_zeropad build failure
     (Michael Ellerman)

   - hardened Kconfig fragment updates (Marco Elver, Lukas Bulwahn)

   - Handle tail call optimization better in LKDTM (Douglas Anderson)

   - Use long form types in overflow.h (Andy Shevchenko)

   - Add flags param to string_get_size() (Andy Shevchenko)

   - Add Coccinelle script for potential struct_size() use (Jacob
     Keller)

   - Fix objtool corner case under KCFI (Josh Poimboeuf)

   - Drop 13 year old backward compat CAP_SYS_ADMIN check (Jingzi Meng)

   - Add str_plural() helper (Michal Wajdeczko, Kees Cook)

   - Ignore relocations in .notes section

   - Add comments to explain how __is_constexpr() works

   - Fix m68k stack alignment expectations in stackinit Kunit test

   - Convert string selftests to KUnit

   - Add KUnit tests for fortified string functions

   - Improve reporting during fortified string warnings

   - Allow non-type arg to type_max() and type_min()

   - Allow strscpy() to be called with only 2 arguments

   - Add binary mode to leaking_addresses scanner

   - Various small cleanups to leaking_addresses scanner

   - Adding wrapping_*() arithmetic helper

   - Annotate initial signed integer wrap-around in refcount_t

   - Add explicit UBSAN section to MAINTAINERS

   - Fix UBSAN self-test warnings

   - Simplify UBSAN build via removal of CONFIG_UBSAN_SANITIZE_ALL

   - Reintroduce UBSAN's signed overflow sanitizer"

* tag 'hardening-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (51 commits)
  selftests/powerpc: Fix load_unaligned_zeropad build failure
  string: Convert helpers selftest to KUnit
  string: Convert selftest to KUnit
  sh: Fix build with CONFIG_UBSAN=y
  compiler.h: Explain how __is_constexpr() works
  overflow: Allow non-type arg to type_max() and type_min()
  VMCI: Fix possible memcpy() run-time warning in vmci_datagram_invoke_guest_handler()
  lib/string_helpers: Add flags param to string_get_size()
  x86, relocs: Ignore relocations in .notes section
  objtool: Fix UNWIND_HINT_{SAVE,RESTORE} across basic blocks
  overflow: Use POD in check_shl_overflow()
  lib: stackinit: Adjust target string to 8 bytes for m68k
  sparc: vdso: Disable UBSAN instrumentation
  kernel.h: Move lib/cmdline.c prototypes to string.h
  leaking_addresses: Provide mechanism to scan binary files
  leaking_addresses: Ignore input device status lines
  leaking_addresses: Use File::Temp for /tmp files
  MAINTAINERS: Update LEAKING_ADDRESSES details
  fortify: Improve buffer overflow reporting
  fortify: Add KUnit tests for runtime overflows
  ...
2024-03-12 14:49:30 -07:00
Linus Torvalds
7ea65c89d8 vfs-6.9.misc
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCZem3wQAKCRCRxhvAZXjc
 otRMAQDeo8qsuuIAcS2KUicKqZR5yMVvrY9r4sQzf7YRcJo5HQD+NQXkKwQuv1VO
 OUeScsic/+I+136AgdjWnlEYO5dp0go=
 =4WKU
 -----END PGP SIGNATURE-----

Merge tag 'vfs-6.9.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull misc vfs updates from Christian Brauner:
 "Misc features, cleanups, and fixes for vfs and individual filesystems.

  Features:

   - Support idmapped mounts for hugetlbfs.

   - Add RWF_NOAPPEND flag for pwritev2(). This allows us to fix a bug
     where the passed offset is ignored if the file is O_APPEND. The new
     flag allows a caller to enforce that the offset is honored to
     conform to posix even if the file was opened in append mode.

   - Move i_mmap_rwsem in struct address_space to avoid false sharing
     between i_mmap and i_mmap_rwsem.

   - Convert efs, qnx4, and coda to use the new mount api.

   - Add a generic is_dot_dotdot() helper that's used by various
     filesystems and the VFS code instead of open-coding it multiple
     times.

   - Recently we've added stable offsets which allows stable ordering
     when iterating directories exported through NFS on e.g., tmpfs
     filesystems. Originally an xarray was used for the offset map but
     that caused slab fragmentation issues over time. This switches the
     offset map to the maple tree which has a dense mode that handles
     this scenario a lot better. Includes tests.

   - Finally merge the case-insensitive improvement series Gabriel has
     been working on for a long time. This cleanly propagates case
     insensitive operations through ->s_d_op which in turn allows us to
     remove the quite ugly generic_set_encrypted_ci_d_ops() operations.
     It also improves performance by trying a case-sensitive comparison
     first and then fallback to case-insensitive lookup if that fails.
     This also fixes a bug where overlayfs would be able to be mounted
     over a case insensitive directory which would lead to all sort of
     odd behaviors.

  Cleanups:

   - Make file_dentry() a simple accessor now that ->d_real() is
     simplified because of the backing file work we did the last two
     cycles.

   - Use the dedicated file_mnt_idmap helper in ntfs3.

   - Use smp_load_acquire/store_release() in the i_size_read/write
     helpers and thus remove the hack to handle i_size reads in the
     filemap code.

   - The SLAB_MEM_SPREAD is a nop now. Remove it from various places in
     fs/

   - It's no longer necessary to perform a second built-in initramfs
     unpack call because we retain the contents of the previous
     extraction. Remove it.

   - Now that we have removed various allocators kfree_rcu() always
     works with kmem caches and kmalloc(). So simplify various places
     that only use an rcu callback in order to handle the kmem cache
     case.

   - Convert the pipe code to use a lockdep comparison function instead
     of open-coding the nesting making lockdep validation easier.

   - Move code into fs-writeback.c that was located in a header but can
     be made static as it's only used in that one file.

   - Rewrite the alignment checking iterators for iovec and bvec to be
     easier to read, and also significantly more compact in terms of
     generated code. This saves 270 bytes of text on x86-64 (with
     clang-18) and 224 bytes on arm64 (with gcc-13). In profiles it also
     saves a bit of time for the same workload.

   - Switch various places to use KMEM_CACHE instead of
     kmem_cache_create().

   - Use inode_set_ctime_to_ts() in inode_set_ctime_current()

   - Use kzalloc() in name_to_handle_at() to avoid kernel infoleak.

   - Various smaller cleanups for eventfds.

  Fixes:

   - Fix various comments and typos, and unneeded initializations.

   - Fix stack allocation hack for clang in the select code.

   - Improve dump_mapping() debug code on a best-effort basis.

   - Fix build errors in various selftests.

   - Avoid wrap-around instrumentation in various places.

   - Don't allow user namespaces without an idmapping to be used for
     idmapped mounts.

   - Fix sysv sb_read() call.

   - Fix fallback implementation of the get_name() export operation"

* tag 'vfs-6.9.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (70 commits)
  hugetlbfs: support idmapped mounts
  qnx4: convert qnx4 to use the new mount api
  fs: use inode_set_ctime_to_ts to set inode ctime to current time
  libfs: Drop generic_set_encrypted_ci_d_ops
  ubifs: Configure dentry operations at dentry-creation time
  f2fs: Configure dentry operations at dentry-creation time
  ext4: Configure dentry operations at dentry-creation time
  libfs: Add helper to choose dentry operations at mount-time
  libfs: Merge encrypted_ci_dentry_ops and ci_dentry_ops
  fscrypt: Drop d_revalidate once the key is added
  fscrypt: Drop d_revalidate for valid dentries during lookup
  fscrypt: Factor out a helper to configure the lookup dentry
  ovl: Always reject mounting over case-insensitive directories
  libfs: Attempt exact-match comparison first during casefolded lookup
  efs: remove SLAB_MEM_SPREAD flag usage
  jfs: remove SLAB_MEM_SPREAD flag usage
  minix: remove SLAB_MEM_SPREAD flag usage
  openpromfs: remove SLAB_MEM_SPREAD flag usage
  proc: remove SLAB_MEM_SPREAD flag usage
  qnx6: remove SLAB_MEM_SPREAD flag usage
  ...
2024-03-11 09:38:17 -07:00
Al Viro
cdb67fdeed rcu pathwalk: prevent bogus hard errors from may_lookup()
If lazy call of ->permission() returns a hard error, check that
try_to_unlazy() succeeds before returning it.  That both makes
life easier for ->permission() instances and closes the race
in ENOTDIR handling - it is possible that positive d_can_lookup()
seen in link_path_walk() applies to the state *after* unlink() +
mkdir(), while nd->inode matches the state prior to that.

Normally seeing e.g. EACCES from permission check in rcu pathwalk
means that with some timings non-rcu pathwalk would've run into
the same; however, running into a non-executable regular file
in the middle of a pathname would not get to permission check -
it would fail with ENOTDIR instead.

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-02-25 02:10:31 -05:00
Roberto Sassu
cd3cec0a02 ima: Move to LSM infrastructure
Move hardcoded IMA function calls (not appraisal-specific functions) from
various places in the kernel to the LSM infrastructure, by introducing a
new LSM named 'ima' (at the end of the LSM list and always enabled like
'integrity').

Having IMA before EVM in the Makefile is sufficient to preserve the
relative order of the new 'ima' LSM in respect to the upcoming 'evm' LSM,
and thus the order of IMA and EVM function calls as when they were
hardcoded.

Make moved functions as static (except ima_post_key_create_or_update(),
which is not in ima_main.c), and register them as implementation of the
respective hooks in the new function init_ima_lsm().

Select CONFIG_SECURITY_PATH, to ensure that the path-based LSM hook
path_post_mknod is always available and ima_post_path_mknod() is always
executed to mark files as new, as before the move.

A slight difference is that IMA and EVM functions registered for the
inode_post_setattr, inode_post_removexattr, path_post_mknod,
inode_post_create_tmpfile, inode_post_set_acl and inode_post_remove_acl
won't be executed for private inodes. Since those inodes are supposed to be
fs-internal, they should not be of interest to IMA or EVM. The S_PRIVATE
flag is used for anonymous inodes, hugetlbfs, reiserfs xattrs, XFS scrub
and kernel-internal tmpfs files.

Conditionally register ima_post_key_create_or_update() if
CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS is enabled. Also, conditionally register
ima_kernel_module_request() if CONFIG_INTEGRITY_ASYMMETRIC_KEYS is enabled.

Finally, add the LSM_ID_IMA case in lsm_list_modules_test.c.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15 23:43:46 -05:00
Roberto Sassu
a7811e34d1 security: Introduce inode_post_create_tmpfile hook
In preparation for moving IMA and EVM to the LSM infrastructure, introduce
the inode_post_create_tmpfile hook.

As temp files can be made persistent, treat new temp files like other new
files, so that the file hash is calculated and stored in the security
xattr.

LSMs could also take some action after temp files have been created.

The new hook cannot return an error and cannot cause the operation to be
canceled.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15 23:43:44 -05:00
Roberto Sassu
08abce60d6 security: Introduce path_post_mknod hook
In preparation for moving IMA and EVM to the LSM infrastructure, introduce
the path_post_mknod hook.

IMA-appraisal requires all existing files in policy to have a file
hash/signature stored in security.ima. An exception is made for empty files
created by mknod, by tagging them as new files.

LSMs could also take some action after files are created.

The new hook cannot return an error and cannot cause the operation to be
reverted.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15 23:43:43 -05:00
Roberto Sassu
8f46ff5767 security: Introduce file_post_open hook
In preparation to move IMA and EVM to the LSM infrastructure, introduce the
file_post_open hook. Also, export security_file_post_open() for NFS.

Based on policy, IMA calculates the digest of the file content and
extends the TPM with the digest, verifies the file's integrity based on
the digest, and/or includes the file digest in the audit log.

LSMs could similarly take action depending on the file content and the
access mask requested with open().

The new hook returns a value and can cause the open to be aborted.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15 23:43:42 -05:00
Tanzir Hasan
66a5c40f60 kernel.h: removed REPEAT_BYTE from kernel.h
This patch creates wordpart.h and includes it in asm/word-at-a-time.h
for all architectures. WORD_AT_A_TIME_CONSTANTS depends on kernel.h
because of REPEAT_BYTE. Moving this to another header and including it
where necessary allows us to not include the bloated kernel.h. Making
this implicit dependency on REPEAT_BYTE explicit allows for later
improvements in the lib/string.c inclusion list.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Tanzir Hasan <tanzirh@google.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20231226-libstringheader-v6-1-80aa08c7652c@google.com
Signed-off-by: Kees Cook <keescook@chromium.org>
2024-02-01 09:47:59 -08:00
Christian Brauner
0000ff2523 Merge tag 'exportfs-6.9' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/cel/linux
Merge exportfs fixes from Chuck Lever:

* tag 'exportfs-6.9' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  fs: Create a generic is_dot_dotdot() utility
  exportfs: fix the fallback implementation of the get_name export operation

Link: https://lore.kernel.org/r/BDC2AEB4-7085-4A7C-8DE8-A659FE1DBA6A@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-01-23 17:56:30 +01:00
Chuck Lever
42c3732fa8 fs: Create a generic is_dot_dotdot() utility
De-duplicate the same functionality in several places by hoisting
the is_dot_dotdot() utility function into linux/fs.h.

Suggested-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-23 10:58:56 -05:00
Linus Torvalds
f16ab99c2e fix buggered locking in bch2_ioctl_subvolume_destroy()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
 -----BEGIN PGP SIGNATURE-----
 
 iHUEABYIAB0WIQQqUNBr3gm4hGXdBJlZ7Krx/gZQ6wUCZaDougAKCRBZ7Krx/gZQ
 60eJAQCtXa908kOFDjSSTetU6aBzWKcCCHszirjhXiTFJv1jTgD/TbvyGs4ku7Ri
 oI4nh1XX4QMVWsup1VETnnLAjt6DhAw=
 =fror
 -----END PGP SIGNATURE-----

Merge tag 'pull-bcachefs-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull bcachefs locking fix from Al Viro:
 "Fix broken locking in bch2_ioctl_subvolume_destroy()"

* tag 'pull-bcachefs-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  bch2_ioctl_subvolume_destroy(): fix locking
  new helper: user_path_locked_at()
2024-01-12 18:04:01 -08:00
Linus Torvalds
bf4e7080ae fix directory locking scheme on rename
broken in 6.5; we really can't lock two unrelated directories
 without holding ->s_vfs_rename_mutex first and in case of
 same-parent rename of a subdirectory 6.5 ends up doing just
 that.
 
 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
 -----BEGIN PGP SIGNATURE-----
 
 iHUEABYIAB0WIQQqUNBr3gm4hGXdBJlZ7Krx/gZQ6wUCZZ+lyQAKCRBZ7Krx/gZQ
 60MWAP94hTqeMIpjhsUIkrTnylrIFaiw4UCWFJzIRG1QQYKqCgD/XUaWI9np7dL6
 0wR/j4CQSdJjiEFKUFE2pD3QoSuJYAQ=
 =+x0+
 -----END PGP SIGNATURE-----

Merge tag 'pull-rename' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull rename updates from Al Viro:
 "Fix directory locking scheme on rename

  This was broken in 6.5; we really can't lock two unrelated directories
  without holding ->s_vfs_rename_mutex first and in case of same-parent
  rename of a subdirectory 6.5 ends up doing just that"

* tag 'pull-rename' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  rename(): avoid a deadlock in the case of parents having no common ancestor
  kill lock_two_inodes()
  rename(): fix the locking of subdirectories
  f2fs: Avoid reading renamed directory if parent does not change
  ext4: don't access the source subdirectory content on same-directory rename
  ext2: Avoid reading renamed directory if parent does not change
  udf_rename(): only access the child content on cross-directory rename
  ocfs2: Avoid touching renamed directory if parent does not change
  reiserfs: Avoid touching renamed directory if parent does not change
2024-01-11 20:00:22 -08:00
Linus Torvalds
a05aea98d4 sysctl-6.8-rc1
To help make the move of sysctls out of kernel/sysctl.c not incur a size
 penalty sysctl has been changed to allow us to not require the sentinel, the
 final empty element on the sysctl array. Joel Granados has been doing all this
 work. On the v6.6 kernel we got the major infrastructure changes required to
 support this. For v6.7 we had all arch/ and drivers/ modified to remove
 the sentinel. For v6.8-rc1 we get a few more updates for fs/ directory only.
 The kernel/ directory is left but we'll save that for v6.9-rc1 as those patches
 are still being reviewed. After that we then can expect also the removal of the
 no longer needed check for procname == NULL.
 
 Let us recap the purpose of this work:
 
   - this helps reduce the overall build time size of the kernel and run time
     memory consumed by the kernel by about ~64 bytes per array
   - the extra 64-byte penalty is no longer inncurred now when we move sysctls
     out from kernel/sysctl.c to their own files
 
 Thomas Weißschuh also sent a few cleanups, for v6.9-rc1 we expect to see further
 work by Thomas Weißschuh with the constificatin of the struct ctl_table.
 
 Due to Joel Granados's work, and to help bring in new blood, I have suggested
 for him to become a maintainer and he's accepted. So for v6.9-rc1 I look forward
 to seeing him sent you a pull request for further sysctl changes. This also
 removes Iurii Zaikin as a maintainer as he has moved on to other projects and
 has had no time to help at all.
 -----BEGIN PGP SIGNATURE-----
 
 iQJGBAABCgAwFiEENnNq2KuOejlQLZofziMdCjCSiKcFAmWdWDESHG1jZ3JvZkBr
 ZXJuZWwub3JnAAoJEM4jHQowkoinjJAP/jTNNoyzWisvrrvmXqR5txFGLOE+wW6x
 Xv9avuiM+DTHsH/wK8CkXEivwDqYNAZEHU7NEcolS5bJX/ddSRwN9b5aSVlCrUdX
 Ab4rXmpeSCNFp9zNszWJsDuBKIqjvsKw7qGleGtgZ2qAUHbbH30VROLWCggaee50
 wU3icDLdwkasxrcMXy4Sq5dT5wYC4j/QelqBGIkYPT14Arl1im5zqPZ95gmO/s/6
 mdicTAmq+hhAUfUBJBXRKtsvxY6CItxe55Q4fjpncLUJLHUw+VPVNoBKFWJlBwlh
 LO3liKFfakPSkil4/en+/+zuMByd0JBkIzIJa+Kk5kjpbHRhK0RkmU4+Y5G5spWN
 jjLfiv6RxInNaZ8EWQBMfjE95A7PmYDQ4TOH08+OvzdDIi6B0BB5tBGQpG9BnyXk
 YsLg1Uo4CwE/vn1/a9w0rhadjUInvmAryhb/uSJYFz/lmApLm2JUpY3/KstwGetb
 z+HmLstJb24Djkr6pH8DcjhzRBHeWQ5p0b4/6B+v1HqAUuEhdbyw1F2GrDywyF3R
 h/UOAaKLm1+ffdA246o9TejKiDU96qEzzXMaCzPKyestaRZuiyuYEMDhYbvtsMV5
 zIdMJj5HQ+U1KHDv4IN99DEj7+/vjE3f4Sjo+POFpQeQ8/d+fxpFNqXVv449dgnb
 6xEkkxsR0ElM
 =2qBt
 -----END PGP SIGNATURE-----

Merge tag 'sysctl-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux

Pull sysctl updates from Luis Chamberlain:
 "To help make the move of sysctls out of kernel/sysctl.c not incur a
  size penalty sysctl has been changed to allow us to not require the
  sentinel, the final empty element on the sysctl array. Joel Granados
  has been doing all this work.

  In the v6.6 kernel we got the major infrastructure changes required to
  support this. For v6.7 we had all arch/ and drivers/ modified to
  remove the sentinel. For v6.8-rc1 we get a few more updates for fs/
  directory only.

  The kernel/ directory is left but we'll save that for v6.9-rc1 as
  those patches are still being reviewed. After that we then can expect
  also the removal of the no longer needed check for procname == NULL.

  Let us recap the purpose of this work:

   - this helps reduce the overall build time size of the kernel and run
     time memory consumed by the kernel by about ~64 bytes per array

   - the extra 64-byte penalty is no longer inncurred now when we move
     sysctls out from kernel/sysctl.c to their own files

  Thomas Weißschuh also sent a few cleanups, for v6.9-rc1 we expect to
  see further work by Thomas Weißschuh with the constificatin of the
  struct ctl_table.

  Due to Joel Granados's work, and to help bring in new blood, I have
  suggested for him to become a maintainer and he's accepted. So for
  v6.9-rc1 I look forward to seeing him sent you a pull request for
  further sysctl changes. This also removes Iurii Zaikin as a maintainer
  as he has moved on to other projects and has had no time to help at
  all"

* tag 'sysctl-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux:
  sysctl: remove struct ctl_path
  sysctl: delete unused define SYSCTL_PERM_EMPTY_DIR
  coda: Remove the now superfluous sentinel elements from ctl_table array
  sysctl: Remove the now superfluous sentinel elements from ctl_table array
  fs: Remove the now superfluous sentinel elements from ctl_table array
  cachefiles: Remove the now superfluous sentinel element from ctl_table array
  sysclt: Clarify the results of selftest run
  sysctl: Add a selftest for handling empty dirs
  sysctl: Fix out of bounds access for empty sysctl registers
  MAINTAINERS: Add Joel Granados as co-maintainer for proc sysctl
  MAINTAINERS: remove Iurii Zaikin from proc sysctl
2024-01-10 17:44:36 -08:00
Joel Granados
9d5b947535 fs: Remove the now superfluous sentinel elements from ctl_table array
This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

Remove sentinel elements ctl_table struct. Special attention was placed in
making sure that an empty directory for fs/verity was created when
CONFIG_FS_VERITY_BUILTIN_SIGNATURES is not defined. In this case we use the
register sysctl call that expects a size.

Signed-off-by: Joel Granados <j.granados@samsung.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-12-28 04:57:57 -08:00
Christian Brauner
2137e15642
Merge branch 'vfs.file'
Bring in the changes to the file infrastructure for this cycle. Mostly
cleanups and some performance tweaks.

* file: remove __receive_fd()
* file: stop exposing receive_fd_user()
* fs: replace f_rcuhead with f_task_work
* file: remove pointless wrapper
* file: s/close_fd_get_file()/file_close_fd()/g
* Improve __fget_files_rcu() code generation (and thus __fget_light())
* file: massage cleanup of files that failed to open

Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-21 13:21:52 +01:00
Alexander Mikhalitsyn
376870aa23
fs: fix doc comment typo fs tree wide
Do the replacement:
s/simply passs @nop_mnt_idmap/simply pass @nop_mnt_idmap/
in the fs/ tree.

Found by chance while working on support for idmapped mounts in fuse.

Cc: Jan Kara <jack@suse.cz>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: <linux-fsdevel@vger.kernel.org>
Cc: <linux-kernel@vger.kernel.org>
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Link: https://lore.kernel.org/r/20231215130927.136917-1-aleksandr.mikhalitsyn@canonical.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-21 13:17:54 +01:00
Al Viro
7cb537b6f6
file: massage cleanup of files that failed to open
A file that has never gotten FMODE_OPENED will never have RCU-accessed
references, its final fput() is equivalent to file_free() and if it
doesn't have FMODE_BACKING either, it can be done from any context and
won't need task_work treatment.

Now that we have SLAB_TYPESAFE_BY_RCU we can simplify this and have
other callers benefit. All of that can be achieved easier is to make
fput() recoginze that case and call file_free() directly.

No need to introduce a special primitive for that. It also allowed
things like failing dentry_open() could benefit from that as well.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[Christian Brauner <brauner@kernel.org>: massage commit message]
Link: https://lore.kernel.org/r/20231126020834.GC38156@ZenIV
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-12 14:24:09 +01:00
Al Viro
a8b0026847 rename(): avoid a deadlock in the case of parents having no common ancestor
... and fix the directory locking documentation and proof of correctness.
Holding ->s_vfs_rename_mutex *almost* prevents ->d_parent changes; the
case where we really don't want it is splicing the root of disconnected
tree to somewhere.

In other words, ->s_vfs_rename_mutex is sufficient to stabilize "X is an
ancestor of Y" only if X and Y are already in the same tree.  Otherwise
it can go from false to true, and one can construct a deadlock on that.

Make lock_two_directories() report an error in such case and update the
callers of lock_rename()/lock_rename_child() to handle such errors.

And yes, such conditions are not impossible to create ;-/

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-11-25 02:54:14 -05:00
Al Viro
22e111ed6c rename(): fix the locking of subdirectories
We should never lock two subdirectories without having taken
->s_vfs_rename_mutex; inode pointer order or not, the "order" proposed
in 28eceeda13 "fs: Lock moved directories" is not transitive, with
the usual consequences.

	The rationale for locking renamed subdirectory in all cases was
the possibility of race between rename modifying .. in a subdirectory to
reflect the new parent and another thread modifying the same subdirectory.
For a lot of filesystems that's not a problem, but for some it can lead
to trouble (e.g. the case when short directory contents is kept in the
inode, but creating a file in it might push it across the size limit
and copy its contents into separate data block(s)).

	However, we need that only in case when the parent does change -
otherwise ->rename() doesn't need to do anything with .. entry in the
first place.  Some instances are lazy and do a tautological update anyway,
but it's really not hard to avoid.

Amended locking rules for rename():
	find the parent(s) of source and target
	if source and target have the same parent
		lock the common parent
	else
		lock ->s_vfs_rename_mutex
		lock both parents, in ancestor-first order; if neither
		is an ancestor of another, lock the parent of source
		first.
	find the source and target.
	if source and target have the same parent
		if operation is an overwriting rename of a subdirectory
			lock the target subdirectory
	else
		if source is a subdirectory
			lock the source
		if target is a subdirectory
			lock the target
	lock non-directories involved, in inode pointer order if both
	source and target are such.

That way we are guaranteed that parents are locked (for obvious reasons),
that any renamed non-directory is locked (nfsd relies upon that),
that any victim is locked (emptiness check needs that, among other things)
and subdirectory that changes parent is locked (needed to protect the update
of .. entries).  We are also guaranteed that any operation locking more
than one directory either takes ->s_vfs_rename_mutex or locks a parent
followed by its child.

Cc: stable@vger.kernel.org
Fixes: 28eceeda13 "fs: Lock moved directories"
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-11-25 02:53:20 -05:00
YangXin
6f672f7b3b fs: namei: Fix spelling mistake "Retuns" to "Returns"
There are two spelling mistake in comments. Fix it.

Signed-off-by: YangXin <yx.0xffff@gmail.com>
Link: https://lore.kernel.org/r/20231118132136.3084-1-yx.0xffff@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-11-20 16:41:50 +01:00
Al Viro
74d016ecc1 new helper: user_path_locked_at()
Equivalent of kern_path_locked() taking dfd/userland name.
User introduced in the next commit.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-11-15 22:41:27 -05:00
Linus Torvalds
3b3f874cc1 vfs-6.7.misc
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCZTpoQAAKCRCRxhvAZXjc
 ovFNAQDgIRjXfZ1Ku+USxsRRdqp8geJVaNc3PuMmYhOYhUenqgEAmC1m+p0y31dS
 P6+HlL16Mqgu0tpLCcJK9BibpDZ0Ew4=
 =7yD1
 -----END PGP SIGNATURE-----

Merge tag 'vfs-6.7.misc' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs

Pull misc vfs updates from Christian Brauner:
 "This contains the usual miscellaneous features, cleanups, and fixes
  for vfs and individual fses.

  Features:

   - Rename and export helpers that get write access to a mount. They
     are used in overlayfs to get write access to the upper mount.

   - Print the pretty name of the root device on boot failure. This
     helps in scenarios where we would usually only print
     "unknown-block(1,2)".

   - Add an internal SB_I_NOUMASK flag. This is another part in the
     endless POSIX ACL saga in a way.

     When POSIX ACLs are enabled via SB_POSIXACL the vfs cannot strip
     the umask because if the relevant inode has POSIX ACLs set it might
     take the umask from there. But if the inode doesn't have any POSIX
     ACLs set then we apply the umask in the filesytem itself. So we end
     up with:

      (1) no SB_POSIXACL -> strip umask in vfs
      (2) SB_POSIXACL    -> strip umask in filesystem

     The umask semantics associated with SB_POSIXACL allowed filesystems
     that don't even support POSIX ACLs at all to raise SB_POSIXACL
     purely to avoid umask stripping. That specifically means NFS v4 and
     Overlayfs. NFS v4 does it because it delegates this to the server
     and Overlayfs because it needs to delegate umask stripping to the
     upper filesystem, i.e., the filesystem used as the writable layer.

     This went so far that SB_POSIXACL is raised eve on kernels that
     don't even have POSIX ACL support at all.

     Stop this blatant abuse and add SB_I_NOUMASK which is an internal
     superblock flag that filesystems can raise to opt out of umask
     handling. That should really only be the two mentioned above. It's
     not that we want any filesystems to do this. Ideally we have all
     umask handling always in the vfs.

   - Make overlayfs use SB_I_NOUMASK too.

   - Now that we have SB_I_NOUMASK, stop checking for SB_POSIXACL in
     IS_POSIXACL() if the kernel doesn't have support for it. This is a
     very old patch but it's only possible to do this now with the wider
     cleanup that was done.

   - Follow-up work on fake path handling from last cycle. Citing mostly
     from Amir:

     When overlayfs was first merged, overlayfs files of regular files
     and directories, the ones that are installed in file table, had a
     "fake" path, namely, f_path is the overlayfs path and f_inode is
     the "real" inode on the underlying filesystem.

     In v6.5, we took another small step by introducing of the
     backing_file container and the file_real_path() helper. This change
     allowed vfs and filesystem code to get the "real" path of an
     overlayfs backing file. With this change, we were able to make
     fsnotify work correctly and report events on the "real" filesystem
     objects that were accessed via overlayfs.

     This method works fine, but it still leaves the vfs vulnerable to
     new code that is not aware of files with fake path. A recent
     example is commit db1d1e8b98 ("IMA: use vfs_getattr_nosec to get
     the i_version"). This commit uses direct referencing to f_path in
     IMA code that otherwise uses file_inode() and file_dentry() to
     reference the filesystem objects that it is measuring.

     This contains work to switch things around: instead of having
     filesystem code opt-in to get the "real" path, have generic code
     opt-in for the "fake" path in the few places that it is needed.

     Is it far more likely that new filesystems code that does not use
     the file_dentry() and file_real_path() helpers will end up causing
     crashes or averting LSM/audit rules if we keep the "fake" path
     exposed by default.

     This change already makes file_dentry() moot, but for now we did
     not change this helper just added a WARN_ON() in ovl_d_real() to
     catch if we have made any wrong assumptions.

     After the dust settles on this change, we can make file_dentry() a
     plain accessor and we can drop the inode argument to ->d_real().

   - Switch struct file to SLAB_TYPESAFE_BY_RCU. This looks like a small
     change but it really isn't and I would like to see everyone on
     their tippie toes for any possible bugs from this work.

     Essentially we've been doing most of what SLAB_TYPESAFE_BY_RCU for
     files since a very long time because of the nasty interactions
     between the SCM_RIGHTS file descriptor garbage collection. So
     extending it makes a lot of sense but it is a subtle change. There
     are almost no places that fiddle with file rcu semantics directly
     and the ones that did mess around with struct file internal under
     rcu have been made to stop doing that because it really was always
     dodgy.

     I forgot to put in the link tag for this change and the discussion
     in the commit so adding it into the merge message:

       https://lore.kernel.org/r/20230926162228.68666-1-mjguzik@gmail.com

  Cleanups:

   - Various smaller pipe cleanups including the removal of a spin lock
     that was only used to protect against writes without pipe_lock()
     from O_NOTIFICATION_PIPE aka watch queues. As that was never
     implemented remove the additional locking from pipe_write().

   - Annotate struct watch_filter with the new __counted_by attribute.

   - Clarify do_unlinkat() cleanup so that it doesn't look like an extra
     iput() is done that would cause issues.

   - Simplify file cleanup when the file has never been opened.

   - Use module helper instead of open-coding it.

   - Predict error unlikely for stale retry.

   - Use WRITE_ONCE() for mount expiry field instead of just commenting
     that one hopes the compiler doesn't get smart.

  Fixes:

   - Fix readahead on block devices.

   - Fix writeback when layztime is enabled and inodes whose timestamp
     is the only thing that changed reside on wb->b_dirty_time. This
     caused excessively large zombie memory cgroup when lazytime was
     enabled as such inodes weren't handled fast enough.

   - Convert BUG_ON() to WARN_ON_ONCE() in open_last_lookups()"

* tag 'vfs-6.7.misc' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (26 commits)
  file, i915: fix file reference for mmap_singleton()
  vfs: Convert BUG_ON to WARN_ON_ONCE in open_last_lookups
  writeback, cgroup: switch inodes with dirty timestamps to release dying cgwbs
  chardev: Simplify usage of try_module_get()
  ovl: rely on SB_I_NOUMASK
  fs: fix umask on NFS with CONFIG_FS_POSIX_ACL=n
  fs: store real path instead of fake path in backing file f_path
  fs: create helper file_user_path() for user displayed mapped file path
  fs: get mnt_writers count for an open backing file's real path
  vfs: stop counting on gcc not messing with mnt_expiry_mark if not asked
  vfs: predict the error in retry_estale as unlikely
  backing file: free directly
  vfs: fix readahead(2) on block devices
  io_uring: use files_lookup_fd_locked()
  file: convert to SLAB_TYPESAFE_BY_RCU
  vfs: shave work on failed file open
  fs: simplify misleading code to remove ambiguity regarding ihold()/iput()
  watch_queue: Annotate struct watch_filter with __counted_by
  fs/pipe: use spinlock in pipe_read() only if there is a watch_queue
  fs/pipe: remove unnecessary spinlock from pipe_write()
  ...
2023-10-30 09:14:19 -10:00
Bernd Schubert
c04d905f6c
vfs: Convert BUG_ON to WARN_ON_ONCE in open_last_lookups
The calling code actually handles -ECHILD, so this BUG_ON
can be converted to WARN_ON_ONCE.

Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Link: https://lore.kernel.org/r/20231023184718.11143-1-bschubert@ddn.com
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Dharmendra Singh <dsingh@ddn.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-24 10:51:05 +02:00
Mateusz Guzik
93faf426e3
vfs: shave work on failed file open
Failed opens (mostly ENOENT) legitimately happen a lot, for example here
are stats from stracing kernel build for few seconds (strace -fc make):

  % time     seconds  usecs/call     calls    errors syscall
  ------ ----------- ----------- --------- --------- ------------------
    0.76    0.076233           5     15040      3688 openat

(this is tons of header files tried in different paths)

In the common case of there being nothing to close (only the file object
to free) there is a lot of overhead which can be avoided.

This is most notably delegation of freeing to task_work, which comes
with an enormous cost (see 021a160abf ("fs: use __fput_sync in
close(2)" for an example).

Benchmarked with will-it-scale with a custom testcase based on
tests/open1.c, stuffed into tests/openneg.c:
[snip]
        while (1) {
                int fd = open("/tmp/nonexistent", O_RDONLY);
                assert(fd == -1);

                (*iterations)++;
        }
[/snip]

Sapphire Rapids, openneg_processes -t 1 (ops/s):
before:	1950013
after:	2914973 (+49%)

file refcount is checked as a safety belt against buggy consumers with
an atomic cmpxchg. Technically it is not necessary, but it happens to
not be measurable due to several other atomics which immediately follow.
Optmizing them away to make this atomic into a problem is left as an
exercise for the reader.

v2:
- unexport fput_badopen and move to fs/internal.h
- handle the refcount with cmpxchg, adjust commentary accordingly
- tweak the commit message

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20230926162228.68666-1-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-19 11:02:48 +02:00
Luís Henriques
6036c5f131
fs: simplify misleading code to remove ambiguity regarding ihold()/iput()
Because 'inode' is being initialised before checking if 'dentry' is negative
it looks like an extra iput() on 'inode' may happen since the ihold() is
done only if the dentry is *not* negative.  In reality this doesn't happen
because d_is_negative() is never true if ->d_inode is NULL.  This patch only
makes the code easier to understand, as I was initially mislead by it.

Signed-off-by: Luís Henriques <lhenriques@suse.de>
Link: https://lore.kernel.org/r/20230928152341.303-1-lhenriques@suse.de
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-19 11:02:48 +02:00
Jeff Layton
5aa8fd9cea
fs: add a new SB_I_NOUMASK flag
SB_POSIXACL must be set when a filesystem supports POSIX ACLs, but NFSv4
also sets this flag to prevent the VFS from applying the umask on
newly-created files. NFSv4 doesn't support POSIX ACLs however, which
causes confusion when other subsystems try to test for them.

Add a new SB_I_NOUMASK flag that allows filesystems to opt-in to umask
stripping without advertising support for POSIX ACLs. Set the new flag
on NFSv4 instead of SB_POSIXACL.

Also, move mode_strip_umask to namei.h and convert init_mknod and
init_mkdir to use it.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230911-acl-fix-v3-1-b25315333f6c@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-19 11:02:47 +02:00
Dan Clash
03adc61eda
audit,io_uring: io_uring openat triggers audit reference count underflow
An io_uring openat operation can update an audit reference count
from multiple threads resulting in the call trace below.

A call to io_uring_submit() with a single openat op with a flag of
IOSQE_ASYNC results in the following reference count updates.

These first part of the system call performs two increments that do not race.

do_syscall_64()
  __do_sys_io_uring_enter()
    io_submit_sqes()
      io_openat_prep()
        __io_openat_prep()
          getname()
            getname_flags()       /* update 1 (increment) */
              __audit_getname()   /* update 2 (increment) */

The openat op is queued to an io_uring worker thread which starts the
opportunity for a race.  The system call exit performs one decrement.

do_syscall_64()
  syscall_exit_to_user_mode()
    syscall_exit_to_user_mode_prepare()
      __audit_syscall_exit()
        audit_reset_context()
           putname()              /* update 3 (decrement) */

The io_uring worker thread performs one increment and two decrements.
These updates can race with the system call decrement.

io_wqe_worker()
  io_worker_handle_work()
    io_wq_submit_work()
      io_issue_sqe()
        io_openat()
          io_openat2()
            do_filp_open()
              path_openat()
                __audit_inode()   /* update 4 (increment) */
            putname()             /* update 5 (decrement) */
        __audit_uring_exit()
          audit_reset_context()
            putname()             /* update 6 (decrement) */

The fix is to change the refcnt member of struct audit_names
from int to atomic_t.

kernel BUG at fs/namei.c:262!
Call Trace:
...
 ? putname+0x68/0x70
 audit_reset_context.part.0.constprop.0+0xe1/0x300
 __audit_uring_exit+0xda/0x1c0
 io_issue_sqe+0x1f3/0x450
 ? lock_timer_base+0x3b/0xd0
 io_wq_submit_work+0x8d/0x2b0
 ? __try_to_del_timer_sync+0x67/0xa0
 io_worker_handle_work+0x17c/0x2b0
 io_wqe_worker+0x10a/0x350

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/lkml/MW2PR2101MB1033FFF044A258F84AEAA584F1C9A@MW2PR2101MB1033.namprd21.prod.outlook.com/
Fixes: 5bd2182d58 ("audit,io_uring,io-wq: add some basic audit support to io_uring")
Signed-off-by: Dan Clash <daclash@linux.microsoft.com>
Link: https://lore.kernel.org/r/20231012215518.GA4048@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-13 18:34:46 +02:00
Matthew Wilcox (Oracle)
35931eb394 fs: Fix kernel-doc warnings
These have a variety of causes and a corresponding variety of solutions.

Signed-off-by: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Message-Id: <20230818200824.2720007-1-willy@infradead.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-19 12:12:12 +02:00
Wang Ming
0d5a4f8f77 fs: Fix error checking for d_hash_and_lookup()
The d_hash_and_lookup() function returns error pointers or NULL.
Most incorrect error checks were fixed, but the one in int path_pts()
was forgotten.

Fixes: eedf265aa0 ("devpts: Make each mount of devpts an independent filesystem.")
Signed-off-by: Wang Ming <machel@vivo.com>
Message-Id: <20230713120555.7025-1-machel@vivo.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-07-14 17:01:23 +02:00
Jan Kara
66d8fc0539
fs: no need to check source
The @source inode must be valid. It is even checked via IS_SWAPFILE()
above making it pretty clear. So no need to check it when we unlock.

What doesn't need to exist is the @target inode. The lock_two_inodes()
helper currently swaps the @inode1 and @inode2 arguments if @inode1 is
NULL to have consistent lock class usage. However, we know that at least
for vfs_rename() that @inode1 is @source and thus is never NULL as per
above. We also know that @source is a different inode than @target as
that is checked right at the beginning of vfs_rename(). So we know that
@source is valid and locked and that @target is locked. So drop the
check whether @source is non-NULL.

Fixes: 28eceeda13 ("fs: Lock moved directories")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202307030026.9sE2pk2x-lkp@intel.com
Message-Id: <20230703-vfs-rename-source-v1-1-37eebb29b65b@kernel.org>
[brauner: use commit message from patch I sent concurrently]
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-07-04 10:20:29 +02:00
Linus Torvalds
1f2300a738 v6.5/vfs.file
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCZJU4WgAKCRCRxhvAZXjc
 oofvAQDs9RJwQUyWHJmQA+tWz5cUE5DviVWCwwul5dQRRCqgaQEA2OIO0gPFaVoq
 1OYOeLyUjl/cpS8e3u4uJtw34jttdQA=
 =AwcR
 -----END PGP SIGNATURE-----

Merge tag 'v6.5/vfs.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs file handling updates from Christian Brauner:
 "This contains Amir's work to fix a long-standing problem where an
  unprivileged overlayfs mount can be used to avoid fanotify permission
  events that were requested for an inode or superblock on the
  underlying filesystem.

  Some background about files opened in overlayfs. If a file is opened
  in overlayfs @file->f_path will refer to a "fake" path. What this
  means is that while @file->f_inode will refer to inode of the
  underlying layer, @file->f_path refers to an overlayfs
  {dentry,vfsmount} pair. The reasons for doing this are out of scope
  here but it is the reason why the vfs has been providing the
  open_with_fake_path() helper for overlayfs for very long time now. So
  nothing new here.

  This is for sure not very elegant and everyone including the overlayfs
  maintainers agree. Improving this significantly would involve more
  fragile and potentially rather invasive changes.

  In various codepaths access to the path of the underlying filesystem
  is needed for such hybrid file. The best example is fsnotify where
  this becomes security relevant. Passing the overlayfs
  @file->f_path->dentry will cause fsnotify to skip generating fsnotify
  events registered on the underlying inode or superblock.

  To fix this we extend the vfs provided open_with_fake_path() concept
  for overlayfs to create a backing file container that holds the real
  path and to expose a helper that can be used by relevant callers to
  get access to the path of the underlying filesystem through the new
  file_real_path() helper. This pattern is similar to what we do in
  d_real() and d_real_inode().

  The first beneficiary is fsnotify and fixes the security sensitive
  problem mentioned above.

  There's a couple of nice cleanups included as well.

  Over time, the old open_with_fake_path() helper added specifically for
  overlayfs a long time ago started to get used in other places such as
  cachefiles. Even though cachefiles have nothing to do with hybrid
  files.

  The only reason cachefiles used that concept was that files opened
  with open_with_fake_path() aren't charged against the caller's open
  file limit by raising FMODE_NOACCOUNT. It's just mere coincidence that
  both overlayfs and cachefiles need to ensure to not overcharge the
  caller for their internal open calls.

  So this work disentangles FMODE_NOACCOUNT use cases and backing file
  use-cases by adding the FMODE_BACKING flag which indicates that the
  file can be used to retrieve the backing file of another filesystem.
  (Fyi, Jens will be sending you a really nice cleanup from Christoph
  that gets rid of 3 FMODE_* flags otherwise this would be the last
  fmode_t bit we'd be using.)

  So now overlayfs becomes the sole user of the renamed
  open_with_fake_path() helper which is now named backing_file_open().
  For internal kernel users such as cachefiles that are only interested
  in FMODE_NOACCOUNT but not in FMODE_BACKING we add a new
  kernel_file_open() helper which opens a file without being charged
  against the caller's open file limit. All new helpers are properly
  documented and clearly annotated to mention their special uses.

  We also rename vfs_tmpfile_open() to kernel_tmpfile_open() to clearly
  distinguish it from vfs_tmpfile() and align it the other kernel_*()
  internal helpers"

* tag 'v6.5/vfs.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  ovl: enable fsnotify events on underlying real files
  fs: use backing_file container for internal files with "fake" f_path
  fs: move kmem_cache_zalloc() into alloc_empty_file*() helpers
  fs: use a helper for opening kernel internal files
  fs: rename {vfs,kernel}_tmpfile_open()
2023-06-26 10:14:36 -07:00
Amir Goldstein
d56e0ddb8f
fs: rename {vfs,kernel}_tmpfile_open()
Overlayfs and cachefiles use vfs_open_tmpfile() to open a tmpfile
without accounting for nr_files.

Rename this helper to kernel_tmpfile_open() to better reflect this
helper is used for kernel internal users.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Message-Id: <20230615112229.2143178-2-amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-06-19 18:09:09 +02:00
Jan Kara
28eceeda13
fs: Lock moved directories
When a directory is moved to a different directory, some filesystems
(udf, ext4, ocfs2, f2fs, and likely gfs2, reiserfs, and others) need to
update their pointer to the parent and this must not race with other
operations on the directory. Lock the directories when they are moved.
Although not all filesystems need this locking, we perform it in
vfs_rename() because getting the lock ordering right is really difficult
and we don't want to expose these locking details to filesystems.

CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230601105830.13168-5-jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-06-02 15:00:18 +02:00
Jan Kara
f23ce75718
fs: Establish locking order for unrelated directories
Currently the locking order of inode locks for directories that are not
in ancestor relationship is not defined because all operations that
needed to lock two directories like this were serialized by
sb->s_vfs_rename_mutex. However some filesystems need to lock two
subdirectories for RENAME_EXCHANGE operations and for this we need the
locking order established even for two tree-unrelated directories.
Provide a helper function lock_two_inodes() that establishes lock
ordering for any two inodes and use it in lock_two_directories().

CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230601105830.13168-4-jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-06-02 15:00:17 +02:00
Linus Torvalds
1ae78a1451 five ksmbd server fixes, and new lock_rename_child VFS helper routine
-----BEGIN PGP SIGNATURE-----
 
 iQGzBAABCgAdFiEE6fsu8pdIjtWE/DpLiiy9cAdyT1EFAmRJ1QwACgkQiiy9cAdy
 T1FoMwv/dQv3nlq7CFW/p82xRGQg1rqE/bLw8iAz2kl2QMNI32mnNZ5vsnAOx5CT
 CXUsdfQTgVsdKQ0yAV0WIAopxOxf4ASmKn8Ej1wJBEREFuwqQUgFE16DALKDPhcW
 77cuPqFEGD1CfbOvM+IjSN1OlDmsu2a3qSuD1OfTxC14s3+mPZitGpSm06PMsaT6
 C17RG6dC+PJmzXOT79OGfPmP1e6103abhv7PUdy7tZdiHi3I2ESXvCUGAoeFzjG9
 i4vxM+WdfStun0sXkZysS+iiyajfbFF8cOkaXp4QG+aplDD5Z2gjV6w+n3phegiX
 N1QvTZ3C8dQEhvmy40DGyLgj2A3/dFqh5bEfA3Mtni2NqEHKG4ng2dQsmkMiNg0M
 iuCHwLUz2kgvc+zl4+HJpKDVF0HG3RHAlzRq0oNEw+lQApzfg/Q+p5ZcZUBjcoSj
 n4fxxNO4bggHmCBHZNDL7VNG81m0YEg8xnDpBPvwtLMO1yEj8RFwW+RTfIwqyOYE
 VK1dcRc1
 =DweL
 -----END PGP SIGNATURE-----

Merge tag '6.4-rc-ksmbd-server-fixes' of git://git.samba.org/ksmbd

Pull ksmbd server updates from Steve French:

 - SMB3.1.1 negotiate context fixes and cleanup

 - new lock_rename_child VFS helper

 - ksmbd fix to avoid unlink race and to use the new VFS helper to avoid
   rename race

* tag '6.4-rc-ksmbd-server-fixes' of git://git.samba.org/ksmbd:
  ksmbd: fix racy issue from using ->d_parent and ->d_name
  ksmbd: remove unused compression negotiate ctx packing
  ksmbd: avoid duplicate negotiate ctx offset increments
  ksmbd: set NegotiateContextCount once instead of every inc
  fs: introduce lock_rename_child() helper
  ksmbd: remove internal.h include
2023-04-29 11:10:39 -07:00
Namjae Jeon
74d7970feb ksmbd: fix racy issue from using ->d_parent and ->d_name
Al pointed out that ksmbd has racy issue from using ->d_parent and ->d_name
in ksmbd_vfs_unlink and smb2_vfs_rename(). and use new lock_rename_child()
to lock stable parent while underlying rename racy.
Introduce vfs_path_parent_lookup helper to avoid out of share access and
export vfs functions like the following ones to use
vfs_path_parent_lookup().
 - rename __lookup_hash() to lookup_one_qstr_excl().
 - export lookup_one_qstr_excl().
 - export getname_kernel() and putname().

vfs_path_parent_lookup() is used for parent lookup of destination file
using absolute pathname given from FILE_RENAME_INFORMATION request.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2023-04-24 00:09:20 -05:00
Al Viro
9bc37e0482 fs: introduce lock_rename_child() helper
Pass the dentry of a source file and the dentry of a destination directory
to lock parent inodes for rename. As soon as this function returns,
->d_parent of the source file dentry is stable and inodes are properly
locked for calling vfs-rename. This helper is needed for ksmbd server.
rename request of SMB protocol has to rename an opened file, no matter
which directory it's in.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-04-20 22:37:05 -04:00
Roberto Sassu
73bb5a9017 fs: Fix description of vfs_tmpfile()
Update the description of vfs_tmpfile() to match the current parameters of
that function.

Fixes: 9751b33865 ("vfs: move open right after ->tmpfile()")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-03-12 20:03:48 -04:00
Linus Torvalds
9fc2f99030 NFSD 6.3 Release Notes
Two significant security enhancements are part of this release:
 
 * NFSD's RPC header encoding and decoding, including RPCSEC GSS
   and gssproxy header parsing, has been overhauled to make it
   more memory-safe.
 
 * Support for Kerberos AES-SHA2-based encryption types has been
   added for both the NFS client and server. This provides a clean
   path for deprecating and removing insecure encryption types
   based on DES and SHA-1. AES-SHA2 is also FIPS-140 compliant, so
   that NFS with Kerberos may now be used on systems with fips
   enabled.
 
 In addition to these, NFSD is now able to handle crossing into an
 auto-mounted mount point on an exported NFS mount. A number of
 fixes have been made to NFSD's server-side copy implementation.
 
 RPC metrics have been converted to per-CPU variables. This helps
 reduce unnecessary cross-CPU and cross-node memory bus traffic,
 and significantly reduces noise when KCSAN is enabled.
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEEKLLlsBKG3yQ88j7+M2qzM29mf5cFAmPzgiYACgkQM2qzM29m
 f5dB2A//eqjpj+FgAN+UjygrwMC4ahAsPX3Sc3FG8/lTAiao3NFVFY2gxAiCPyVE
 CFk+tUyfL23oXvbyfIBe3LhxSBOf621xU6up2OzqAzJqh1Q9iUWB6as3I14to8ZU
 sWpxXo5ofwk1hzkbrvOAVkyfY0emwsr00iBeWMawkpBe8FZEQA31OYj3/xHr6bBI
 zEVlZPBZAZlp0DZ74tb+bBLs/EOnqKj+XLWcogCH13JB3sn2umF6cQNkYgsxvHGa
 TNQi4LEdzWZGme242LfBRiGGwm1xuVIjlAhYV/R1wIjaknE3QBzqfXc6lJx74WII
 HaqpRJGrKqdo7B+1gaXCl/AMS7YluED1CBrxuej0wBG7l2JEB7m2MFMQ4LTQjgsn
 nrr3P70DgbB4LuPCPyUS7dtsMmUXabIqP7niiCR4T1toH6lBmHAgEi4cFmkzg7Cd
 EoFzn888mtDpfx4fghcsRWS5oKXEzbPJfu5+IZOD63+UB+NGpi0Xo2s23sJPK8vz
 kqK/X63JYOUxWUvK0zkj/c/wW1cLqIaBwnSKbShou5/BL+cZVI+uJYrnEesgpoB2
 5fh/cZv3hdcoOPO7OfcjCLQYy4J6RCWajptnk/hcS3lMvBTBrnq697iAqCVURDKU
 Xfmlf7XbBwje+sk4eHgqVGEqqVjrEmoqbmA2OS44WSS5LDvxXdI=
 =ZG/7
 -----END PGP SIGNATURE-----

Merge tag 'nfsd-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux

Pull nfsd updates from Chuck Lever:
 "Two significant security enhancements are part of this release:

   - NFSD's RPC header encoding and decoding, including RPCSEC GSS and
     gssproxy header parsing, has been overhauled to make it more
     memory-safe.

   - Support for Kerberos AES-SHA2-based encryption types has been added
     for both the NFS client and server. This provides a clean path for
     deprecating and removing insecure encryption types based on DES and
     SHA-1. AES-SHA2 is also FIPS-140 compliant, so that NFS with
     Kerberos may now be used on systems with fips enabled.

  In addition to these, NFSD is now able to handle crossing into an
  auto-mounted mount point on an exported NFS mount. A number of fixes
  have been made to NFSD's server-side copy implementation.

  RPC metrics have been converted to per-CPU variables. This helps
  reduce unnecessary cross-CPU and cross-node memory bus traffic, and
  significantly reduces noise when KCSAN is enabled"

* tag 'nfsd-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux: (121 commits)
  NFSD: Clean up nfsd_symlink()
  NFSD: copy the whole verifier in nfsd_copy_write_verifier
  nfsd: don't fsync nfsd_files on last close
  SUNRPC: Fix occasional warning when destroying gss_krb5_enctypes
  nfsd: fix courtesy client with deny mode handling in nfs4_upgrade_open
  NFSD: fix problems with cleanup on errors in nfsd4_copy
  nfsd: fix race to check ls_layouts
  nfsd: don't hand out delegation on setuid files being opened for write
  SUNRPC: Remove ->xpo_secure_port()
  SUNRPC: Clean up the svc_xprt_flags() macro
  nfsd: remove fs/nfsd/fault_inject.c
  NFSD: fix leaked reference count of nfsd4_ssc_umount_item
  nfsd: clean up potential nfsd_file refcount leaks in COPY codepath
  nfsd: zero out pointers after putting nfsd_files on COPY setup error
  SUNRPC: Fix whitespace damage in svcauth_unix.c
  nfsd: eliminate __nfs4_get_fd
  nfsd: add some kerneldoc comments for stateid preprocessing functions
  nfsd: eliminate find_deleg_file_locked
  nfsd: don't take nfsd4_copy ref for OP_OFFLOAD_STATUS
  SUNRPC: Add encryption self-tests
  ...
2023-02-22 14:21:40 -08:00
Linus Torvalds
05e6295f7b fs.idmapped.v6.3
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCY+5NlQAKCRCRxhvAZXjc
 orOaAP9i2h3OJy95nO2Fpde0Bt2UT+oulKCCcGlvXJ8/+TQpyQD/ZQq47gFQ0EAz
 Br5NxeyGeecAb0lHpFz+CpLGsxMrMwQ=
 =+BG5
 -----END PGP SIGNATURE-----

Merge tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping

Pull vfs idmapping updates from Christian Brauner:

 - Last cycle we introduced the dedicated struct mnt_idmap type for
   mount idmapping and the required infrastucture in 256c8aed2b ("fs:
   introduce dedicated idmap type for mounts"). As promised in last
   cycle's pull request message this converts everything to rely on
   struct mnt_idmap.

   Currently we still pass around the plain namespace that was attached
   to a mount. This is in general pretty convenient but it makes it easy
   to conflate namespaces that are relevant on the filesystem with
   namespaces that are relevant on the mount level. Especially for
   non-vfs developers without detailed knowledge in this area this was a
   potential source for bugs.

   This finishes the conversion. Instead of passing the plain namespace
   around this updates all places that currently take a pointer to a
   mnt_userns with a pointer to struct mnt_idmap.

   Now that the conversion is done all helpers down to the really
   low-level helpers only accept a struct mnt_idmap argument instead of
   two namespace arguments.

   Conflating mount and other idmappings will now cause the compiler to
   complain loudly thus eliminating the possibility of any bugs. This
   makes it impossible for filesystem developers to mix up mount and
   filesystem idmappings as they are two distinct types and require
   distinct helpers that cannot be used interchangeably.

   Everything associated with struct mnt_idmap is moved into a single
   separate file. With that change no code can poke around in struct
   mnt_idmap. It can only be interacted with through dedicated helpers.
   That means all filesystems are and all of the vfs is completely
   oblivious to the actual implementation of idmappings.

   We are now also able to extend struct mnt_idmap as we see fit. For
   example, we can decouple it completely from namespaces for users that
   don't require or don't want to use them at all. We can also extend
   the concept of idmappings so we can cover filesystem specific
   requirements.

   In combination with the vfs{g,u}id_t work we finished in v6.2 this
   makes this feature substantially more robust and thus difficult to
   implement wrong by a given filesystem and also protects the vfs.

 - Enable idmapped mounts for tmpfs and fulfill a longstanding request.

   A long-standing request from users had been to make it possible to
   create idmapped mounts for tmpfs. For example, to share the host's
   tmpfs mount between multiple sandboxes. This is a prerequisite for
   some advanced Kubernetes cases. Systemd also has a range of use-cases
   to increase service isolation. And there are more users of this.

   However, with all of the other work going on this was way down on the
   priority list but luckily someone other than ourselves picked this
   up.

   As usual the patch is tiny as all the infrastructure work had been
   done multiple kernel releases ago. In addition to all the tests that
   we already have I requested that Rodrigo add a dedicated tmpfs
   testsuite for idmapped mounts to xfstests. It is to be included into
   xfstests during the v6.3 development cycle. This should add a slew of
   additional tests.

* tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: (26 commits)
  shmem: support idmapped mounts for tmpfs
  fs: move mnt_idmap
  fs: port vfs{g,u}id helpers to mnt_idmap
  fs: port fs{g,u}id helpers to mnt_idmap
  fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap
  fs: port i_{g,u}id_{needs_}update() to mnt_idmap
  quota: port to mnt_idmap
  fs: port privilege checking helpers to mnt_idmap
  fs: port inode_owner_or_capable() to mnt_idmap
  fs: port inode_init_owner() to mnt_idmap
  fs: port acl to mnt_idmap
  fs: port xattr to mnt_idmap
  fs: port ->permission() to pass mnt_idmap
  fs: port ->fileattr_set() to pass mnt_idmap
  fs: port ->set_acl() to pass mnt_idmap
  fs: port ->get_acl() to pass mnt_idmap
  fs: port ->tmpfile() to pass mnt_idmap
  fs: port ->rename() to pass mnt_idmap
  fs: port ->mknod() to pass mnt_idmap
  fs: port ->mkdir() to pass mnt_idmap
  ...
2023-02-20 11:53:11 -08:00
Richard Weinberger
e1f19857f9 fs: namei: Allow follow_down() to uncover auto mounts
This function is only used by NFSD to cross mount points.
If a mount point is of type auto mount, follow_down() will
not uncover it. Add LOOKUP_AUTOMOUNT to the lookup flags
to have ->d_automount() called when NFSD walks down the
mount tree.

Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Ian Kent <raven@themaw.net>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-02-20 09:20:08 -05:00
Christian Brauner
e67fe63341
fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap
Convert to struct mnt_idmap.
Remove legacy file_mnt_user_ns() and mnt_user_ns().

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19 09:24:29 +01:00
Christian Brauner
9452e93e6d
fs: port privilege checking helpers to mnt_idmap
Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19 09:24:29 +01:00