Currently, we take fc->lock there only to check for fc->connected.
But this flag is changed only on connection abort, which is very
rare operation.
So allow checking fc->connected under just fc->bg_lock and use this lock
(as well as fc->lock) when resetting fc->connected.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
To reduce contention of fc->lock, this patch introduces bg_lock for
protection of fields related to background queue. These are:
max_background, congestion_threshold, num_background, active_background,
bg_queue and blocked.
This allows next patch to make async reads not requiring fc->lock, so async
reads and writes will have better performance executed in parallel.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Functions sequences like request_end()->flush_bg_queue() require that
max_background and congestion_threshold are constant during their
execution. Otherwise, checks like
if (fc->num_background == fc->max_background)
made in different time may behave not like expected.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Since they are of unsigned int type, it's allowed to read them
unlocked during reporting to userspace. Let's underline this fact
with READ_ONCE() macroses.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This cleanup patch makes the function to use the primitive
instead of direct dereferencing.
Also, move fiq dereferencing out of cycle, since it's
always constant.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
There are several FUSE filesystems that can implement server-side copy
or other efficient copy/duplication/clone methods. The copy_file_range()
syscall is the standard interface that users have access to while not
depending on external libraries that bypass FUSE.
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Using waitqueue_active() is racy. Make sure we issue a wake_up()
unconditionally after storing into fc->blocked. After that it's okay to
optimize with waitqueue_active() since the first wake up provides the
necessary barrier for all waiters, not the just the woken one.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: 3c18ef8117 ("fuse: optimize wake_up")
Cc: <stable@vger.kernel.org> # v3.10
Otherwise fuse_dev_do_write() could come in and finish off the request, and
the set_bit(FR_SENT, ...) could trigger the WARN_ON(test_bit(FR_SENT, ...))
in request_end().
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reported-by: syzbot+ef054c4d3f64cd7f7cec@syzkaller.appspotmai
Fixes: 46c34a348b ("fuse: no fc->lock for pqueue parts")
Cc: <stable@vger.kernel.org> # v4.2
This contains various bug fixes and cleanups.
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Merge tag 'fuse-update-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
Pull fuse update from Miklos Szeredi:
"Various bug fixes and cleanups"
* tag 'fuse-update-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: reduce allocation size for splice_write
fuse: use kvmalloc to allocate array of pipe_buffer structs.
fuse: convert last timespec use to timespec64
fs: fuse: Adding new return type vm_fault_t
fuse: simplify fuse_abort_conn()
fuse: Add missed unlock_page() to fuse_readpages_fill()
fuse: Don't access pipe->buffers without pipe_lock()
fuse: fix initial parallel dirops
fuse: Fix oops at process_init_reply()
fuse: umount should wait for all requests
fuse: fix unlocked access to processing queue
fuse: fix double request_end()
Pull core signal handling updates from Eric Biederman:
"It was observed that a periodic timer in combination with a
sufficiently expensive fork could prevent fork from every completing.
This contains the changes to remove the need for that restart.
This set of changes is split into several parts:
- The first part makes PIDTYPE_TGID a proper pid type instead
something only for very special cases. The part starts using
PIDTYPE_TGID enough so that in __send_signal where signals are
actually delivered we know if the signal is being sent to a a group
of processes or just a single process.
- With that prep work out of the way the logic in fork is modified so
that fork logically makes signals received while it is running
appear to be received after the fork completes"
* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (22 commits)
signal: Don't send signals to tasks that don't exist
signal: Don't restart fork when signals come in.
fork: Have new threads join on-going signal group stops
fork: Skip setting TIF_SIGPENDING in ptrace_init_task
signal: Add calculate_sigpending()
fork: Unconditionally exit if a fatal signal is pending
fork: Move and describe why the code examines PIDNS_ADDING
signal: Push pid type down into complete_signal.
signal: Push pid type down into __send_signal
signal: Push pid type down into send_signal
signal: Pass pid type into do_send_sig_info
signal: Pass pid type into send_sigio_to_task & send_sigurg_to_task
signal: Pass pid type into group_send_sig_info
signal: Pass pid and pid type into send_sigqueue
posix-timers: Noralize good_sigevent
signal: Use PIDTYPE_TGID to clearly store where file signals will be sent
pid: Implement PIDTYPE_TGID
pids: Move the pgrp and session pid pointers from task_struct to signal_struct
kvm: Don't open code task_pid in kvm_vcpu_ioctl
pids: Compute task_tgid using signal->leader_pid
...
Pull vfs icache updates from Al Viro:
- NFS mkdir/open_by_handle race fix
- analogous solution for FUSE, replacing the one currently in mainline
- new primitive to be used when discarding halfway set up inodes on
failed object creation; gives sane warranties re icache lookups not
returning such doomed by still not freed inodes. A bunch of
filesystems switched to that animal.
- Miklos' fix for last cycle regression in iget5_locked(); -stable will
need a slightly different variant, unfortunately.
- misc bits and pieces around things icache-related (in adfs and jfs).
* 'work.mkdir' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
jfs: don't bother with make_bad_inode() in ialloc()
adfs: don't put inodes into icache
new helper: inode_fake_hash()
vfs: don't evict uninitialized inode
jfs: switch to discard_new_inode()
ext2: make sure that partially set up inodes won't be returned by ext2_iget()
udf: switch to discard_new_inode()
ufs: switch to discard_new_inode()
btrfs: switch to discard_new_inode()
new primitive: discard_new_inode()
kill d_instantiate_no_diralias()
nfs_instantiate(): prevent multiple aliases for directory inode
The only user is fuse_create_new_entry(), and there it's used to
mitigate the same mkdir/open-by-handle race as in nfs_mkdir().
The same solution applies - unhash the mkdir argument, then
call d_splice_alias() and if that returns a reference to preexisting
alias, dput() and report success. ->mkdir() argument left unhashed
negative with the preexisting alias moved in the right place is just
fine from the ->mkdir() callers point of view.
Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The 'bufs' array contains 'pipe->buffers' elements, but the
fuse_dev_splice_write() uses only 'pipe->nrbufs' elements.
So reduce the allocation size to 'pipe->nrbufs' elements.
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
The amount of pipe->buffers is basically controlled by userspace by
fcntl(... F_SETPIPE_SZ ...) so it could be large. High order allocations
could be slow (if memory is heavily fragmented) or may fail if the order
is larger than PAGE_ALLOC_COSTLY_ORDER.
Since the 'bufs' doesn't need to be physically contiguous, use
the kvmalloc_array() to allocate memory. If high order
page isn't available, the kvamalloc*() will fallback to 0-order.
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
All of fuse uses 64-bit timestamps with the exception of the
fuse_change_attributes(), so let's convert this one as well.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Use new return type vm_fault_t for fault handler in struct
vm_operations_struct. For now, this is just documenting that the function
returns a VM_FAULT value rather than an errno. Once all instances are
converted, vm_fault_t will become a distinct type.
commit 1c8f422059 ("mm: change return type to vm_fault_t")
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
The above error path returns with page unlocked, so this place seems also
to behave the same.
Fixes: f8dbdf8182 ("fuse: rework fuse_readpages()")
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
fuse_dev_splice_write() reads pipe->buffers to determine the size of
'bufs' array before taking the pipe_lock(). This is not safe as
another thread might change the 'pipe->buffers' between the allocation
and taking the pipe_lock(). So we end up with too small 'bufs' array.
Move the bufs allocations inside pipe_lock()/pipe_unlock() to fix this.
Fixes: dd3bb14f44 ("fuse: support splice() writing to fuse device")
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: <stable@vger.kernel.org> # v2.6.35
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
If parallel dirops are enabled in FUSE_INIT reply, then first operation may
leave fi->mutex held.
Reported-by: syzbot <syzbot+3f7b29af1baa9d0a55be@syzkaller.appspotmail.com>
Fixes: 5c672ab3f0 ("fuse: serialize dirops by default")
Cc: <stable@vger.kernel.org> # v4.7
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
syzbot is hitting NULL pointer dereference at process_init_reply().
This is because deactivate_locked_super() is called before response for
initial request is processed.
Fix this by aborting and waiting for all requests (including FUSE_INIT)
before resetting fc->sb.
Original patch by Tetsuo Handa <penguin-kernel@I-love.SKAURA.ne.jp>.
Reported-by: syzbot <syzbot+b62f08f4d5857755e3bc@syzkaller.appspotmail.com>
Fixes: e27c9d3877 ("fuse: fuse: add time_gran to INIT_OUT")
Cc: <stable@vger.kernel.org> # v3.19
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
fuse_abort_conn() does not guarantee that all async requests have actually
finished aborting (i.e. their ->end() function is called). This could
actually result in still used inodes after umount.
Add a helper to wait until all requests are fully done. This is done by
looking at the "num_waiting" counter. When this counter drops to zero, we
can be sure that no more requests are outstanding.
Fixes: 0d8e84b043 ("fuse: simplify request abort")
Cc: <stable@vger.kernel.org> # v4.2
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
fuse_dev_release() assumes that it's the only one referencing the
fpq->processing list, but that's not true, since fuse_abort_conn() can be
doing the same without any serialization between the two.
Fixes: c3696046be ("fuse: separate pqueue for clones")
Cc: <stable@vger.kernel.org> # v4.2
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Refcounting of request is broken when fuse_abort_conn() is called and
request is on the fpq->io list:
- ref is taken too late
- then it is not dropped
Fixes: 0d8e84b043 ("fuse: simplify request abort")
Cc: <stable@vger.kernel.org> # v4.2
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
The cost is the the same and this removes the need
to worry about complications that come from de_thread
and group_leader changing.
__task_pid_nr_ns has been updated to take advantage of this change.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
__gfs2_lookup(), gfs2_create_inode(), nfs_finish_open() and fuse_create_open()
don't need 'opened' anymore. Get rid of that argument in those.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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>
This is a late set of changes from Deepa Dinamani doing an automated
treewide conversion of the inode and iattr structures from 'timespec'
to 'timespec64', to push the conversion from the VFS layer into the
individual file systems.
There were no conflicts between this and the contents of linux-next
until just before the merge window, when we saw multiple problems:
- A minor conflict with my own y2038 fixes, which I could address
by adding another patch on top here.
- One semantic conflict with late changes to the NFS tree. I addressed
this by merging Deepa's original branch on top of the changes that
now got merged into mainline and making sure the merge commit includes
the necessary changes as produced by coccinelle.
- A trivial conflict against the removal of staging/lustre.
- Multiple conflicts against the VFS changes in the overlayfs tree.
These are still part of linux-next, but apparently this is no longer
intended for 4.18 [1], so I am ignoring that part.
As Deepa writes:
The series aims to switch vfs timestamps to use struct timespec64.
Currently vfs uses struct timespec, which is not y2038 safe.
The series involves the following:
1. Add vfs helper functions for supporting struct timepec64 timestamps.
2. Cast prints of vfs timestamps to avoid warnings after the switch.
3. Simplify code using vfs timestamps so that the actual
replacement becomes easy.
4. Convert vfs timestamps to use struct timespec64 using a script.
This is a flag day patch.
Next steps:
1. Convert APIs that can handle timespec64, instead of converting
timestamps at the boundaries.
2. Update internal data structures to avoid timestamp conversions.
Thomas Gleixner adds:
I think there is no point to drag that out for the next merge window.
The whole thing needs to be done in one go for the core changes which
means that you're going to play that catchup game forever. Let's get
over with it towards the end of the merge window.
[1] https://www.spinics.net/lists/linux-fsdevel/msg128294.html
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Merge tag 'vfs-timespec64' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground
Pull inode timestamps conversion to timespec64 from Arnd Bergmann:
"This is a late set of changes from Deepa Dinamani doing an automated
treewide conversion of the inode and iattr structures from 'timespec'
to 'timespec64', to push the conversion from the VFS layer into the
individual file systems.
As Deepa writes:
'The series aims to switch vfs timestamps to use struct timespec64.
Currently vfs uses struct timespec, which is not y2038 safe.
The series involves the following:
1. Add vfs helper functions for supporting struct timepec64
timestamps.
2. Cast prints of vfs timestamps to avoid warnings after the switch.
3. Simplify code using vfs timestamps so that the actual replacement
becomes easy.
4. Convert vfs timestamps to use struct timespec64 using a script.
This is a flag day patch.
Next steps:
1. Convert APIs that can handle timespec64, instead of converting
timestamps at the boundaries.
2. Update internal data structures to avoid timestamp conversions'
Thomas Gleixner adds:
'I think there is no point to drag that out for the next merge
window. The whole thing needs to be done in one go for the core
changes which means that you're going to play that catchup game
forever. Let's get over with it towards the end of the merge window'"
* tag 'vfs-timespec64' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground:
pstore: Remove bogus format string definition
vfs: change inode times to use struct timespec64
pstore: Convert internal records to timespec64
udf: Simplify calls to udf_disk_stamp_to_time
fs: nfs: get rid of memcpys for inode times
ceph: make inode time prints to be long long
lustre: Use long long type to print inode time
fs: add timespec64_truncate()
The most interesting part of this update is user namespace support, mostly
done by Eric Biederman. This enables safe unprivileged fuse mounts within
a user namespace.
There are also a couple of fixes for bugs found by syzbot and miscellaneous
fixes and cleanups.
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Merge tag 'fuse-update-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
Pull fuse updates from Miklos Szeredi:
"The most interesting part of this update is user namespace support,
mostly done by Eric Biederman. This enables safe unprivileged fuse
mounts within a user namespace.
There are also a couple of fixes for bugs found by syzbot and
miscellaneous fixes and cleanups"
* tag 'fuse-update-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: don't keep dead fuse_conn at fuse_fill_super().
fuse: fix control dir setup and teardown
fuse: fix congested state leak on aborted connections
fuse: Allow fully unprivileged mounts
fuse: Ensure posix acls are translated outside of init_user_ns
fuse: add writeback documentation
fuse: honor AT_STATX_FORCE_SYNC
fuse: honor AT_STATX_DONT_SYNC
fuse: Restrict allow_other to the superblock's namespace or a descendant
fuse: Support fuse filesystems outside of init_user_ns
fuse: Fail all requests with invalid uids or gids
fuse: Remove the buggy retranslation of pids in fuse_dev_do_read
fuse: return -ECONNABORTED on /dev/fuse read after abort
fuse: atomic_o_trunc should truncate pagecache
syzbot is reporting use-after-free at fuse_kill_sb_blk() [1].
Since sb->s_fs_info field is not cleared after fc was released by
fuse_conn_put() when initialization failed, fuse_kill_sb_blk() finds
already released fc and tries to hold the lock. Fix this by clearing
sb->s_fs_info field after calling fuse_conn_put().
[1] https://syzkaller.appspot.com/bug?id=a07a680ed0a9290585ca424546860464dd9658db
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+ec3986119086fe4eec97@syzkaller.appspotmail.com>
Fixes: 3b463ae0c6 ("fuse: invalidation reverse calls")
Cc: John Muir <john@jmuir.com>
Cc: Csaba Henk <csaba@gluster.com>
Cc: Anand Avati <avati@redhat.com>
Cc: <stable@vger.kernel.org> # v2.6.31
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
syzbot is reporting NULL pointer dereference at fuse_ctl_remove_conn() [1].
Since fc->ctl_ndents is incremented by fuse_ctl_add_conn() when new_inode()
failed, fuse_ctl_remove_conn() reaches an inode-less dentry and tries to
clear d_inode(dentry)->i_private field.
Fix by only adding the dentry to the array after being fully set up.
When tearing down the control directory, do d_invalidate() on it to get rid
of any mounts that might have been added.
[1] https://syzkaller.appspot.com/bug?id=f396d863067238959c91c0b7cfc10b163638cac6
Reported-by: syzbot <syzbot+32c236387d66c4516827@syzkaller.appspotmail.com>
Fixes: bafa96541b ("[PATCH] fuse: add control filesystem")
Cc: <stable@vger.kernel.org> # v2.6.18
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
If a connection gets aborted while congested, FUSE can leave
nr_wb_congested[] stuck until reboot causing wait_iff_congested() to
wait spuriously which can lead to severe performance degradation.
The leak is caused by gating congestion state clearing with
fc->connected test in request_end(). This was added way back in 2009
by 26c3679101 ("fuse: destroy bdi on umount"). While the commit
description doesn't explain why the test was added, it most likely was
to avoid dereferencing bdi after it got destroyed.
Since then, bdi lifetime rules have changed many times and now we're
always guaranteed to have access to the bdi while the superblock is
alive (fc->sb).
Drop fc->connected conditional to avoid leaking congestion states.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Joshua Miller <joshmiller@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: stable@vger.kernel.org # v2.6.29+
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Now that the fuse and the vfs work is complete. Allow the fuse filesystem
to be mounted by the root user in a user namespace.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Ensure the translation happens by failing to read or write
posix acls when the filesystem has not indicated it supports
posix acls.
This ensures that modern cached posix acl support is available
and used when dealing with posix acls. This is important
because only that path has the code to convernt the uids and
gids in posix acls into the user namespace of a fuse filesystem.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Files on FUSE can change at any point in time without IMA being able
to detect it. The file data read for the file signature verification
could be totally different from what is subsequently read, making the
signature verification useless.
FUSE can be mounted by unprivileged users either today with fusermount
installed with setuid, or soon with the upcoming patches to allow FUSE
mounts in a non-init user namespace.
This patch sets the SB_I_IMA_UNVERIFIABLE_SIGNATURE flag and when
appropriate sets the SB_I_UNTRUSTED_MOUNTER flag.
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Seth Forshee <seth.forshee@canonical.com>
Cc: Dongsu Park <dongsu@kinvolk.io>
Cc: Alban Crequy <alban@kinvolk.io>
Acked-by: Serge Hallyn <serge@hallyn.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
The description of this flag says "Don't sync attributes with the server".
In other words: always use the attributes cached in the kernel and don't
send network or local messages to refresh the attributes.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Unprivileged users are normally restricted from mounting with the
allow_other option by system policy, but this could be bypassed for a mount
done with user namespace root permissions. In such cases allow_other should
not allow users outside the userns to access the mount as doing so would
give the unprivileged user the ability to manipulate processes it would
otherwise be unable to manipulate. Restrict allow_other to apply to users
in the same userns used at mount or a descendant of that namespace. Also
export current_in_userns() for use by fuse when built as a module.
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Dongsu Park <dongsu@kinvolk.io>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
In order to support mounts from namespaces other than init_user_ns, fuse
must translate uids and gids to/from the userns of the process servicing
requests on /dev/fuse. This patch does that, with a couple of restrictions
on the namespace:
- The userns for the fuse connection is fixed to the namespace
from which /dev/fuse is opened.
- The namespace must be the same as s_user_ns.
These restrictions simplify the implementation by avoiding the need to pass
around userns references and by allowing fuse to rely on the checks in
setattr_prepare for ownership changes. Either restriction could be relaxed
in the future if needed.
For cuse the userns used is the opener of /dev/cuse. Semantically the cuse
support does not appear safe for unprivileged users. Practically the
permissions on /dev/cuse only make it accessible to the global root user.
If something slips through the cracks in a user namespace the only users
who will be able to use the cuse device are those users mapped into the
user namespace.
Translation in the posix acl is updated to use the uuser namespace of the
filesystem. Avoiding cases which might bypass this translation is handled
in a following change.
This change is stronlgy based on a similar change from Seth Forshee and
Dongsu Park.
Cc: Seth Forshee <seth.forshee@canonical.com>
Cc: Dongsu Park <dongsu@kinvolk.io>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Upon a cursory examinination the uid and gid of a fuse request are
necessary for correct operation. Failing a fuse request where those
values are not reliable seems a straight forward and reliable means of
ensuring that fuse requests with bad data are not sent or processed.
In most cases the vfs will avoid actions it suspects will cause
an inode write back of an inode with an invalid uid or gid. But that does
not map precisely to what fuse is doing, so test for this and solve
this at the fuse level as well.
Performing this work in fuse_req_init_context is cheap as the code is
already performing the translation here and only needs to check the
result of the translation to see if things are not representable in
a form the fuse server can handle.
[SzM] Don't zero the context for the nofail case, just keep using the
munging version (makes sense for debugging and doesn't hurt).
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
At the point of fuse_dev_do_read the user space process that initiated the
action on the fuse filesystem may no longer exist. The process have been
killed or may have fired an asynchronous request and exited.
If the initial process has exited, the code "pid_vnr(find_pid_ns(in->h.pid,
fc->pid_ns)" will either return a pid of 0, or in the unlikely event that
the pid has been reallocated it can return practically any pid. Any pid is
possible as the pid allocator allocates pid numbers in different pid
namespaces independently.
The only way to make translation in fuse_dev_do_read reliable is to call
get_pid in fuse_req_init_context, and pid_vnr followed by put_pid in
fuse_dev_do_read. That reference counting in other contexts has been shown
to bounce cache lines between processors and in general be slow. So that
is not desirable.
The only known user of running the fuse server in a different pid namespace
from the filesystem does not care what the pids are in the fuse messages so
removing this code should not matter.
Getting the translation to a server running outside of the pid namespace of
a container can still be achieved by playing setns games at mount time. It
is also possible to add an option to pass a pid namespace into the fuse
filesystem at mount time.
Fixes: 5d6d3a301c ("fuse: allow server to run in different pid_ns")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Currently the userspace has no way of knowing whether the fuse
connection ended because of umount or abort via sysfs. It makes it hard
for filesystems to free the mountpoint after abort without worrying
about removing some new mount.
The patch fixes it by returning different errors when userspace reads
from /dev/fuse (-ENODEV for umount and -ECONNABORTED for abort).
Add a new capability flag FUSE_ABORT_ERROR. If set and the connection is
gone because of sysfs abort, reading from the device will return
-ECONNABORTED.
Signed-off-by: Szymon Lukasz <noh4hss@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fuse has an "atomic_o_trunc" mode, where userspace filesystem uses the
O_TRUNC flag in the OPEN request to truncate the file atomically with the
open.
In this mode there's no need to send a SETATTR request to userspace after
the open, so fuse_do_setattr() checks this mode and returns. But this
misses the important step of truncating the pagecache.
Add the missing parts of truncation to the ATTR_OPEN branch.
Reported-by: Chad Austin <chadaustin@fb.com>
Fixes: 6ff958edbf ("fuse: add atomic open+truncate support")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Cc: <stable@vger.kernel.org>
This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:
for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
done
with de-mangling cleanups yet to come.
NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do. But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.
The next patch from Al will sort out the final differences, and we
should be all done.
Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
