linux-stable.git/fs, branch linux-6.7.y

exec: Fix NOMMU linux_binprm::exec in transfer_args_to_stack()

2024-04-03T13:11:49+00:00

commit 2aea94ac14d1e0a8ae9e34febebe208213ba72f7 upstream.

In NOMMU kernel the value of linux_binprm::p is the offset inside the
temporary program arguments array maintained in separate pages in the
linux_binprm::page. linux_binprm::exec being a copy of linux_binprm::p
thus must be adjusted when that array is copied to the user stack.
Without that adjustment the value passed by the NOMMU kernel to the ELF
program in the AT_EXECFN entry of the aux array doesn't make any sense
and it may break programs that try to access memory pointed to by that
entry.

Adjust linux_binprm::exec before the successful return from the
transfer_args_to_stack().

Cc: 
Fixes: b6a2fea39318 ("mm: variable length argument support")
Fixes: 5edc2a5123a7 ("binfmt_elf_fdpic: wire up AT_EXECFD, AT_EXECFN, AT_SECURE")
Signed-off-by: Max Filippov 
Link: https://lore.kernel.org/r/20240320182607.1472887-1-jcmvbkbc@gmail.com
Signed-off-by: Kees Cook 
Signed-off-by: Greg Kroah-Hartman

btrfs: zoned: use zone aware sb location for scrub

2024-04-03T13:11:48+00:00

commit 74098a989b9c3370f768140b7783a7aaec2759b3 upstream.

At the moment scrub_supers() doesn't grab the super block's location via
the zoned device aware btrfs_sb_log_location() but via btrfs_sb_offset().

This leads to checksum errors on 'scrub' as we're not accessing the
correct location of the super block.

So use btrfs_sb_log_location() for getting the super blocks location on
scrub.

Reported-by: WA AM 
Link: http://lore.kernel.org/linux-btrfs/CANU2Z0EvUzfYxczLgGUiREoMndE9WdQnbaawV5Fv5gNXptPUKw@mail.gmail.com
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Qu Wenruo 
Reviewed-by: Naohiro Aota 
Signed-off-by: Johannes Thumshirn 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba 
Signed-off-by: Greg Kroah-Hartman

btrfs: zoned: don't skip block groups with 100% zone unusable

2024-04-03T13:11:48+00:00

commit a8b70c7f8600bc77d03c0b032c0662259b9e615e upstream.

Commit f4a9f219411f ("btrfs: do not delete unused block group if it may be
used soon") changed the behaviour of deleting unused block-groups on zoned
filesystems. Starting with this commit, we're using
btrfs_space_info_used() to calculate the number of used bytes in a
space_info. But btrfs_space_info_used() also accounts
btrfs_space_info::bytes_zone_unusable as used bytes.

So if a block group is 100% zone_unusable it is skipped from the deletion
step.

In order not to skip fully zone_unusable block-groups, also check if the
block-group has bytes left that can be used on a zoned filesystem.

Fixes: f4a9f219411f ("btrfs: do not delete unused block group if it may be used soon")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Filipe Manana 
Signed-off-by: Johannes Thumshirn 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba 
Signed-off-by: Greg Kroah-Hartman

btrfs: fix race in read_extent_buffer_pages()

2024-04-03T13:11:48+00:00

commit ef1e68236b9153c27cb7cf29ead0c532870d4215 upstream.

There are reports from tree-checker that detects corrupted nodes,
without any obvious pattern so possibly an overwrite in memory.
After some debugging it turns out there's a race when reading an extent
buffer the uptodate status can be missed.

To prevent concurrent reads for the same extent buffer,
read_extent_buffer_pages() performs these checks:

    /* (1) */
    if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
        return 0;

    /* (2) */
    if (test_and_set_bit(EXTENT_BUFFER_READING, &eb->bflags))
        goto done;

At this point, it seems safe to start the actual read operation. Once
that completes, end_bbio_meta_read() does

    /* (3) */
    set_extent_buffer_uptodate(eb);

    /* (4) */
    clear_bit(EXTENT_BUFFER_READING, &eb->bflags);

Normally, this is enough to ensure only one read happens, and all other
callers wait for it to finish before returning.  Unfortunately, there is
a racey interleaving:

    Thread A | Thread B | Thread C
    ---------+----------+---------
       (1)   |          |
             |    (1)   |
       (2)   |          |
       (3)   |          |
       (4)   |          |
             |    (2)   |
             |          |    (1)

When this happens, thread B kicks of an unnecessary read. Worse, thread
C will see UPTODATE set and return immediately, while the read from
thread B is still in progress.  This race could result in tree-checker
errors like this as the extent buffer is concurrently modified:

    BTRFS critical (device dm-0): corrupted node, root=256
    block=8550954455682405139 owner mismatch, have 11858205567642294356
    expect [256, 18446744073709551360]

Fix it by testing UPTODATE again after setting the READING bit, and if
it's been set, skip the unnecessary read.

Fixes: d7172f52e993 ("btrfs: use per-buffer locking for extent_buffer reading")
Link: https://lore.kernel.org/linux-btrfs/CAHk-=whNdMaN9ntZ47XRKP6DBes2E5w7fi-0U3H2+PS18p+Pzw@mail.gmail.com/
Link: https://lore.kernel.org/linux-btrfs/f51a6d5d7432455a6a858d51b49ecac183e0bbc9.1706312914.git.wqu@suse.com/
Link: https://lore.kernel.org/linux-btrfs/c7241ea4-fcc6-48d2-98c8-b5ea790d6c89@gmx.com/
CC: stable@vger.kernel.org # 6.5+
Reviewed-by: Qu Wenruo 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Tavian Barnes 
Reviewed-by: David Sterba 
[ minor update of changelog ]
Signed-off-by: David Sterba 
Signed-off-by: Greg Kroah-Hartman

btrfs: validate device maj:min during open

2024-04-03T13:11:48+00:00

commit 9f7eb8405dcbc79c5434821e9e3e92abe187ee8e upstream.

Boris managed to create a device capable of changing its maj:min without
altering its device path.

Only multi-devices can be scanned. A device that gets scanned and remains
in the btrfs kernel cache might end up with an incorrect maj:min.

Despite the temp-fsid feature patch did not introduce this bug, it could
lead to issues if the above multi-device is converted to a single device
with a stale maj:min. Subsequently, attempting to mount the same device
with the correct maj:min might mistake it for another device with the same
fsid, potentially resulting in wrongly auto-enabling the temp-fsid feature.

To address this, this patch validates the device's maj:min at the time of
device open and updates it if it has changed since the last scan.

CC: stable@vger.kernel.org # 6.7+
Fixes: a5b8a5f9f835 ("btrfs: support cloned-device mount capability")
Reported-by: Boris Burkov 
Co-developed-by: Boris Burkov 
Reviewed-by: Boris Burkov #
Signed-off-by: Anand Jain 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba 
Signed-off-by: Greg Kroah-Hartman

btrfs: do not skip re-registration for the mounted device

2024-04-03T13:11:45+00:00

commit d565fffa68560ac540bf3d62cc79719da50d5e7a upstream.

There are reports that since version 6.7 update-grub fails to find the
device of the root on systems without initrd and on a single device.

This looks like the device name changed in the output of
/proc/self/mountinfo:

6.5-rc5 working

18 1 0:16 / / rw,noatime - btrfs /dev/sda8 ...

6.7 not working:

17 1 0:15 / / rw,noatime - btrfs /dev/root ...

and "update-grub" shows this error:

/usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?)

This looks like it's related to the device name, but grub-probe
recognizes the "/dev/root" path and tries to find the underlying device.
However there's a special case for some filesystems, for btrfs in
particular.

The generic root device detection heuristic is not done and it all
relies on reading the device infos by a btrfs specific ioctl. This ioctl
returns the device name as it was saved at the time of device scan (in
this case it's /dev/root).

The change in 6.7 for temp_fsid to allow several single device
filesystem to exist with the same fsid (and transparently generate a new
UUID at mount time) was to skip caching/registering such devices.

This also skipped mounted device. One step of scanning is to check if
the device name hasn't changed, and if yes then update the cached value.

This broke the grub-probe as it always read the device /dev/root and
couldn't find it in the system. A temporary workaround is to create a
symlink but this does not survive reboot.

The right fix is to allow updating the device path of a mounted
filesystem even if this is a single device one.

In the fix, check if the device's major:minor number matches with the
cached device. If they do, then we can allow the scan to happen so that
device_list_add() can take care of updating the device path. The file
descriptor remains unchanged.

This does not affect the temp_fsid feature, the UUID of the mounted
filesystem remains the same and the matching is based on device major:minor
which is unique per mounted filesystem.

This covers the path when the device (that exists for all mounted
devices) name changes, updating /dev/root to /dev/sdx. Any other single
device with filesystem and is not mounted is still skipped.

Note that if a system is booted and initial mount is done on the
/dev/root device, this will be the cached name of the device. Only after
the command "btrfs device scan" it will change as it triggers the
rename.

The fix was verified by users whose systems were affected.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=218353
Link: https://lore.kernel.org/lkml/CAKLYgeJ1tUuqLcsquwuFqjDXPSJpEiokrWK2gisPKDZLs8Y2TQ@mail.gmail.com/
Fixes: bc27d6f0aa0e ("btrfs: scan but don't register device on single device filesystem")
CC: stable@vger.kernel.org # 6.7+
Tested-by: Alex Romosan
Tested-by: CHECK_1234543212345@protonmail.com
Signed-off-by: Anand Jain
Reviewed-by: David Sterba
Signed-off-by: David Sterba
Signed-off-by: Greg Kroah-Hartman

btrfs: fix deadlock with fiemap and extent locking

2024-04-03T13:11:42+00:00

commit b0ad381fa7690244802aed119b478b4bdafc31dd upstream.

While working on the patchset to remove extent locking I got a lockdep
splat with fiemap and pagefaulting with my new extent lock replacement
lock.

This deadlock exists with our normal code, we just don't have lockdep
annotations with the extent locking so we've never noticed it.

Since we're copying the fiemap extent to user space on every iteration
we have the chance of pagefaulting.  Because we hold the extent lock for
the entire range we could mkwrite into a range in the file that we have
mmap'ed.  This would deadlock with the following stack trace

[<0>] lock_extent+0x28d/0x2f0
[<0>] btrfs_page_mkwrite+0x273/0x8a0
[<0>] do_page_mkwrite+0x50/0xb0
[<0>] do_fault+0xc1/0x7b0
[<0>] __handle_mm_fault+0x2fa/0x460
[<0>] handle_mm_fault+0xa4/0x330
[<0>] do_user_addr_fault+0x1f4/0x800
[<0>] exc_page_fault+0x7c/0x1e0
[<0>] asm_exc_page_fault+0x26/0x30
[<0>] rep_movs_alternative+0x33/0x70
[<0>] _copy_to_user+0x49/0x70
[<0>] fiemap_fill_next_extent+0xc8/0x120
[<0>] emit_fiemap_extent+0x4d/0xa0
[<0>] extent_fiemap+0x7f8/0xad0
[<0>] btrfs_fiemap+0x49/0x80
[<0>] __x64_sys_ioctl+0x3e1/0xb50
[<0>] do_syscall_64+0x94/0x1a0
[<0>] entry_SYSCALL_64_after_hwframe+0x6e/0x76

I wrote an fstest to reproduce this deadlock without my replacement lock
and verified that the deadlock exists with our existing locking.

To fix this simply don't take the extent lock for the entire duration of
the fiemap.  This is safe in general because we keep track of where we
are when we're searching the tree, so if an ordered extent updates in
the middle of our fiemap call we'll still emit the correct extents
because we know what offset we were on before.

The only place we maintain the lock is searching delalloc.  Since the
delalloc stuff can change during writeback we want to lock the extent
range so we have a consistent view of delalloc at the time we're
checking to see if we need to set the delalloc flag.

With this patch applied we no longer deadlock with my testcase.

CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Filipe Manana 
Signed-off-by: Josef Bacik 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba 
Signed-off-by: Greg Kroah-Hartman

fs/aio: Check IOCB_AIO_RW before the struct aio_kiocb conversion

2024-04-03T13:11:39+00:00

commit 961ebd120565cb60cebe21cb634fbc456022db4a upstream.

The first kiocb_set_cancel_fn() argument may point at a struct kiocb
that is not embedded inside struct aio_kiocb. With the current code,
depending on the compiler, the req->ki_ctx read happens either before
the IOCB_AIO_RW test or after that test. Move the req->ki_ctx read such
that it is guaranteed that the IOCB_AIO_RW test happens first.

Reported-by: Eric Biggers 
Cc: Benjamin LaHaise 
Cc: Eric Biggers 
Cc: Christoph Hellwig 
Cc: Avi Kivity 
Cc: Sandeep Dhavale 
Cc: Jens Axboe 
Cc: Greg Kroah-Hartman 
Cc: Kent Overstreet 
Cc: stable@vger.kernel.org
Fixes: b820de741ae4 ("fs/aio: Restrict kiocb_set_cancel_fn() to I/O submitted via libaio")
Signed-off-by: Bart Van Assche 
Link: https://lore.kernel.org/r/20240304235715.3790858-1-bvanassche@acm.org
Reviewed-by: Jens Axboe 
Reviewed-by: Eric Biggers 
Signed-off-by: Christian Brauner 
Signed-off-by: Greg Kroah-Hartman

ksmbd: fix potencial out-of-bounds when buffer offset is invalid

2024-04-03T13:11:29+00:00

[ Upstream commit c6cd2e8d2d9aa7ee35b1fa6a668e32a22a9753da ]

I found potencial out-of-bounds when buffer offset fields of a few requests
is invalid. This patch set the minimum value of buffer offset field to
->Buffer offset to validate buffer length.

Cc: stable@vger.kernel.org
Signed-off-by: Namjae Jeon 
Signed-off-by: Steve French 
Signed-off-by: Sasha Levin

NFSD: Fix nfsd_clid_class use of __string_len() macro

2024-04-03T13:11:29+00:00

[ Upstream commit 9388a2aa453321bcf1ad2603959debea9e6ab6d4 ]

I'm working on restructuring the __string* macros so that it doesn't need
to recalculate the string twice. That is, it will save it off when
processing __string() and the __assign_str() will not need to do the work
again as it currently does.

Currently __string_len(item, src, len) doesn't actually use "src", but my
changes will require src to be correct as that is where the __assign_str()
will get its value from.

The event class nfsd_clid_class has:

  __string_len(name, name, clp->cl_name.len)

But the second "name" does not exist and causes my changes to fail to
build. That second parameter should be: clp->cl_name.data.

Link: https://lore.kernel.org/linux-trace-kernel/20240222122828.3d8d213c@gandalf.local.home

Cc: Neil Brown 
Cc: Olga Kornievskaia 
Cc: Dai Ngo 
Cc: Tom Talpey 
Cc: stable@vger.kernel.org
Fixes: d27b74a8675ca ("NFSD: Use new __string_len C macros for nfsd_clid_class")
Acked-by: Chuck Lever 
Acked-by: Jeff Layton 
Signed-off-by: Steven Rostedt (Google) 
Signed-off-by: Sasha Levin