The invalidHandle, swapfile, oplock_break_cancelled, offload,
and status_file_deleted fields are stored in the same bitfield byte
in struct cifsFileInfo, but are updated in different code paths that
may run simultaneously, and are protected by different locks. Since
bitfield assignments generate byte-level read-modify-write operations,
a modification to one flag can overwrite a concurrent modification to
another flag.
To avoid these races, convert these flags from a bitfield to
separate bool fields.
Closes: https://lore.kernel.org/r/7689764e-c0f6-4016-9557-b54cf4a3de4e@redhat.com
Fixes: 3bc303c254 ("cifs: convert oplock breaks to use slow_work facility (try #4)")
Fixes: 4e8aea30f7 ("smb3: enable swap on SMB3 mounts")
Fixes: ffceb7640c ("smb: client: do not defer close open handles to deleted files")
Fixes: 173217bd73 ("smb3: retrying on failed server close")
Signed-off-by: Frank Sorenson <sorenson@redhat.com>
Cc: stable@vger.kernel.org
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
When signing, cifs computes the SMB signature over the pagecache folios
in place and then hands those same folios to the socket. If a buffered
write mutates a folio while a write subrequest is still in flight, the
signature no longer matches the data that follows it, the server rejects
the write with STATUS_ACCESS_DENIED (-EACCES), and the error is latched
in the mapping, so the next fsync()/fallocate() returns -EIO.
Mark the mapping for stable writes so netfs_perform_write() waits for
writeback to complete before modifying an in-flight folio. This is
only needed when the connection is signed.
Fixes: 3ee1a1fc39 ("cifs: Cut over to using netfslib")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
smb2_readv_callback() sets NETFS_SREQ_HIT_EOF whenever a short read
lines up with netfs_read_remote_i_size(inode), the server's EOF as the
client currently believes it. That belief can be stale: after a lease
downgrade and handle reopen, the tracked remote_i_size can sit below
the client's own i_size while an extending write hasn't reached the
server yet. A read in that gap comes back short for a reason that has
nothing to do with the file's real size, but was still marked HIT_EOF,
and netfs reports a short read for it as-is.
Only treat it as real EOF when the position is also at or past the
client's own i_size; otherwise mark it NETFS_SREQ_CLEAR_TAIL instead,
which tells netfs the shortfall is safe to zero-fill rather than
report as a short read.
This is what fsx (generic/363) sees as "short read: 0x0 bytes instead
of 0x<n>" against a Windows server.
Fixes: 1da29f2c39 ("netfs, cifs: Fix handling of short DIO read")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
smb3_simple_falloc() refuses any fallocate that clears FALLOC_FL_KEEP_SIZE
with -EOPNOTSUPP whenever the inode is not read caching:
/* if file not oplocked can't be sure whether asking to extend size */
if (!CIFS_CACHE_READ(cifsi))
if (!keep_size) {
...
return rc;
}
As with smb3_zero_range(), the read lease is only needed to trust the
cached size when deciding whether the request extends the file. When it
is not held, the size can instead be fetched from the server, which is
authoritative, rather than refusing the request outright: after
flushing, query the server's end of file and take the larger of it and
the cached size for the interior-vs-extend decision. The larger of the
two is used because the server's end of file reflects another client's
growth while the cached size reflects this client's own writes that may
not have reached the server yet; using the server size alone would
wrongly treat an interior request as extending when a range flush left
an extending write unwritten.
smb3_simple_fallocate_range(), which performs the actual interior
emulation, decided whether the range already lies past EOF from its own
i_size_read(inode) rather than the old_eof computed above. In the
leaseless case, that is exactly the stale, undershooting size this
patch works around: a genuinely interior range can read as past EOF by
that stale count, which skips the FSCTL_QUERY_ALLOCATED_RANGES check
entirely and overwrites already-allocated server data with zeroes
instead of only filling the holes. Pass old_eof into
smb3_simple_fallocate_range() and use it for that comparison instead of
re-deriving a second, inconsistent one.
Rejecting interior requests is observed as generic/363 randomly failing
against Windows Server with
do_preallocate: fallocate: Operation not supported
fsx issues an interior, non-KEEP_SIZE preallocate while the inode is
transiently not read caching: the server had just downgraded the file's
lease from RWH to RH after breaking the write caching, and the ensuing
handle reopen/revalidation left CIFS_CACHE_READ momentarily clear. The
range sat within the server's end of file, so no extend was needed, yet
it was refused and fsx aborted. This keeps the emulation correct even
when a genuine lease break from another client leaves the inode
without read caching -- the case the -EOPNOTSUPP guard turned into a
hard failure. The extra flush and round trip only happen when both
keep_size is false and no read lease is held; every other case is
unchanged.
Fixes: 9ccf321623 ("Add support for original fallocate")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
smb3_zero_range() refuses any FALLOC_FL_ZERO_RANGE that clears
FALLOC_FL_KEEP_SIZE with -EOPNOTSUPP whenever the inode is not read
caching:
/* if file not oplocked can't be sure whether asking to extend size */
rc = -EOPNOTSUPP;
if (keep_size == false && !CIFS_CACHE_READ(cifsi))
goto zero_range_exit;
The read lease is only needed to trust the cached i_size when deciding
whether the range extends the file. When it is not held, the size can
instead be fetched from the server, which is authoritative, rather than
refusing the request outright: query the server's end of file and take
the larger of it and the cached size for the interior-vs-extend
decision. The larger of the two is used because the server's end of
file reflects another client's growth while the cached size reflects
this client's own writes that may not have reached the server yet;
using the server size alone would wrongly shrink the file when the
range flush above left an extending write unwritten.
The query isn't lease-protected either, so its result is only trusted to
confirm the range is interior, never to justify extending: if it still
shows the range going past EOF, refuse with -EOPNOTSUPP instead of
calling SMB2_set_eof(), which could otherwise shrink the file if another
client extended it further between the query and the call. For the same
reason, take the larger of the already-computed i_size and a fresh
i_size_read(inode) right before that call, instead of relying on either
alone: the local variable carries the query's result, which is never
written back to the inode, while a concurrent write on this client can
still extend the cached i_size during the flush, the query, or the
zero-data round trip that happen in between.
Rejecting interior ranges is observed as generic/363 randomly failing
against Windows Server with
do_zero_range: fallocate: Operation not supported
fsx issues an interior, non-KEEP_SIZE zero range while the inode is
transiently not read caching: the server had just downgraded the file's
lease from RWH to RH after breaking the write caching, and the ensuing
handle reopen/revalidation left CIFS_CACHE_READ momentarily clear. The
range sat well within the server's end of file, so no extend was
needed, yet the range was refused and fsx aborted. This keeps the
emulation correct even when a genuine lease break from another client
leaves the inode without read caching -- the case the -EOPNOTSUPP guard
turned into a hard failure. The extra round trip only happens on the
no-lease path; the common cached case is unchanged.
Fixes: 30175628bf ("[SMB3] Enable fallocate -z support for SMB3 mounts")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
cifs_file_copychunk_range() and the clone (FICLONE) path of
cifs_remap_file_range() do not serialise the destination page cache
against the server-side copy the way the other server-side range
operations (smb3_zero_range(), smb3_punch_hole(), smb3_collapse_range()
and smb3_insert_range()) do.
cifs_file_copychunk_range() invalidates the destination range with
filemap_invalidate_inode(), which takes and drops the mapping's
invalidate_lock internally, so the lock is no longer held when the
copychunk ioctl is issued. It also never drains in-flight netfs I/O on
the target. The clone path never takes the invalidate_lock at all (only
i_rwsem), uses a bare truncate_inode_pages_range() and likewise does not
drain outstanding I/O.
As a result an asynchronous destination writeback can complete after the
server-side copy/clone has run and reinstate stale data over the region
just written by the server, corrupting the file. This is the same class
of corruption as commit d7d2adcd02 ("smb/client: flush dirty data
before punching a hole") and has been seen randomly in generic/363
against Windows Server.
Fix both paths to follow the established ordering: hold the target
mapping's invalidate_lock across the flush and invalidation of the
destination and the server ioctl, and call netfs_wait_for_outstanding_io()
on the target to drain in-flight writes before the ioctl is issued. Only
the target inode's invalidate_lock is required, as the source is merely
flushed and not invalidated; i_rwsem (already held via
lock_two_nondirectories()) is acquired before the invalidate_lock,
matching the VFS lock ordering. Since filemap_invalidate_inode() takes
that same lock internally, replace it with its own unmap/flush/invalidate
steps instead of calling it, and return early on a zero-length copy to
avoid a range underflow.
Fixes: 8101d6e112 ("cifs: Fix copy offload to flush destination region")
Fixes: c54fc3a4f3 ("cifs: Fix flushing, invalidation and file size with FICLONE")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
smb3_zero_range() emulates FALLOC_FL_ZERO_RANGE by invalidating the
page cache over the target range with truncate_pagecache_range() and
then issuing FSCTL_SET_ZERO_DATA to the server.
Dirty data was only flushed conditionally, when the range reached or
extended EOF. For a purely interior zero range that does not reach
EOF, no flush happened, so a dirty folio overlapping the range could
be written back to the server after the FSCTL and refill the range
that was just zeroed with stale data.
Fix this by unconditionally flushing and waiting for dirty data in the
range before invalidating the page cache and issuing
FSCTL_SET_ZERO_DATA, exactly as was done for smb3_punch_hole() in
commit d7d2adcd02 ("smb/client: flush dirty data before punching a
hole"); the two paths are structurally identical here.
This is observed as generic/363 randomly reading stale data where a
zeroed range is expected against Windows Server.
Fixes: 91d1dfae46 ("cifs: Fix FALLOC_FL_ZERO_RANGE to preflush buffered part of target region")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
cifs_do_truncate() flushes the pagecache with filemap_write_and_wait()
before resetting the file size to zero, but that does not wait for
direct/async I/O that was already in flight, which can complete after the
truncate and reinstate stale data past the new EOF.
Drain outstanding netfs I/O with netfs_wait_for_outstanding_io()
before resizing the file.
Reported-by: Frank Sorenson <sorenson@redhat.com>
Fixes: a8603b52b3 ("smb: client: fix data corruption with concurrent writes and O_TRUNC")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
The mode 0 / FALLOC_FL_KEEP_SIZE fallocate emulation for small interior
ranges in smb3_simple_fallocate_range() issues
FSCTL_QUERY_ALLOCATED_RANGES and zero-fills any sub-range the server
reports as an unallocated hole, to force block allocation without
changing file contents.
This is unsafe against Windows servers. Per the Win32 documentation,
FSCTL_QUERY_ALLOCATED_RANGES only reports ranges that *may* contain
nonzero data and is explicitly not coherent with recently written data:
"a call to FSCTL_QUERY_ALLOCATED_RANGES [after writing to a network
file] would not necessarily return a correct list of allocated
regions. To ensure coherency [...] flush the data to the file"
fsx (generic/363) reproduces the resulting corruption against Windows
Server 2022: a range is written, an uncached read returns the data, yet
the next FSCTL_QUERY_ALLOCATED_RANGES on that range reports it as a whole
hole, so the emulation overwrites live data with zeroes. A network trace
confirmed the WRITE, the READ returning data and the query returning an
empty range list within microseconds. Samba does not exhibit this; its
query is coherent with the written data.
Write back the dirty pages, drain any outstanding I/O and issue an SMB2
FLUSH to force the server to commit the data before querying the
allocated ranges, so the query reflects the data actually present.
With this, generic/363 passes against both Windows Server 2022 and Samba
over 100000 fsx operations.
Fixes: 966a3cb7c7 ("cifs: improve fallocate emulation")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
cifs_remap_file_range() discarded the pagecache only for the folios
overlapping the destination region, so when a clone extends the file the
folio straddling the old EOF - which may hold data dirtied past EOF
through an mmap - was never dropped and became visible as file content
once the file was extended.
Start the discard at the smaller of fstart and the old EOF. i_size is
still old here, so nothing past the old EOF is flushed to the server.
Fixes: c54fc3a4f3 ("cifs: Fix flushing, invalidation and file size with FICLONE")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
cifs_file_copychunk_range() invalidated the pagecache only for the
destination region, so when a copy extends the file the folio straddling
the old EOF - which may hold data dirtied past EOF through an mmap - was
never dropped and became visible as file content once the file was
extended.
Start the invalidation at the smaller of the destination offset and the
old EOF. filemap_invalidate_inode() writes back before invalidating
while i_size is still old, so nothing past the old EOF is flushed to the
server.
Fixes: 8101d6e112 ("cifs: Fix copy offload to flush destination region")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
smb3_zero_range() removed the pagecache only for the range being zeroed,
so when it extends the file the folio straddling the old EOF - which may
hold data dirtied past EOF through an mmap - was never dropped and became
visible as file content once the file was extended.
Lower the discard boundary to the smaller of the zero-range offset and the
old EOF.
Fixes: 72c419d9b0 ("cifs: fix smb3_zero_range so it can expand the file-size when required")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
cifs_setsize() relied on pagecache_isize_extended() to zero the tail of
the folio straddling the old EOF, but that helper is a no-op on CIFS
(i_blkbits is 14), so data dirtied past EOF through an mmap survived
and became visible once the file was extended.
Use netfs_clear_stale_post_isize() instead, called after i_size is
updated since cifs_setsize() callers hold i_rwsem exclusively for the
whole resize. truncate_pagecache() is then called as in
truncate_setsize(): a no-op on extend, and it drops the pagecache
beyond the new EOF on shrink.
Also thread old_size as an explicit parameter through cifs_setsize()
and cifs_resize_file_locked(), captured by each caller before its own
resize RPC. This closes a race where a concurrent stat() could adopt
the RPC's already-updated server size via is_size_safe_to_change()
before cifs_setsize() reads old_size itself.
Closes: https://sashiko.dev/#/patchset/20260921230755.1133425-1-pc%40manguebit.org
Fixes: c510edb973 ("cifs: call pagecache_isize_extended() in cifs_setsize() when extending")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
An O_CREAT open can find an existing symlink or another non-regular
inode. cifs_atomic_open() calls finish_open() on it and attaches a
cifsFileInfo. Symlink inodes have no CIFS release operation, so the
dentry reference held by cifsFileInfo is leaked. FMODE_OPENED also
prevents the VFS from following the symlink.
Track whether cifs_do_create() returned an open server handle. For
non-regular inodes, close the handle if present, remove the pending
open, and call finish_no_open() so the VFS can continue the lookup.
Do not set FMODE_CREATED unless a regular file was opened. For
O_NOFOLLOW with __O_REGULAR, return -ELOOP before the VFS's
-EFTYPE check.
Defer closing a legacy POSIX handle on a non-regular inode until
after inode lookup. This avoids closing it again if lookup fails.
Fixes: d2c127197d ("cifs: implement i_op->atomic_open()")
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: stable@vger.kernel.org
Currently, get_targets() uses GFP_ATOMIC to allocate the cache target
iterator and to duplicate t->name. The callers of get_targets() are
in a sleepable context; therefore, switch to GFP_KERNEL to reduce
risk of failure and reduce pressure on emergency pools in low-memory
scenarios.
Signed-off-by: Fredric Cover <fredric.cover.lkernel@gmail.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
The POSIX extension specifications have now been published:
https://smb3posix.org/
Suggested-by: Paulo Alcantara <pc@manguebit.org>
Reviewed-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Signed-off-by: ZhangGuoDong <zhangguodong@kylinos.cn>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
smb2_compound_op() saves the result from compound_send_recv() in
tmp_rc. For SMB2_OP_OPEN_QUERY it then parses the CREATE contexts, but
the final assignment of rc from tmp_rc discards a parsing error. A
malformed create-context response can therefore be reported as
successful to smb2_query_path_info().
Keep a create-context parsing error in tmp_rc so it survives per-command
response processing and is returned to the caller.
Fixes: b07687edee ("cifs: Improve SMB2+ stat() to work also without FILE_READ_ATTRIBUTES")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Assisted-by: LLM
Co-developed-by: Luxing Yin <root@tr0jan.top>
Signed-off-by: Luxing Yin <root@tr0jan.top>
Signed-off-by: Zihan Xi <zihanx@nebusec.ai>
Tested-by: Frank Sorenson <sorenson@redhat.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
compound_send_recv() waits for responses in order. If a later wait is
interrupted, or if a later MID fails during response synchronization, an
earlier CREATE may already have opened a remote handle. The earlier mid
is then released without invoking handle_cancelled_mid(), leaving the
remote handle open because no FID was copied to the caller.
Mark completed earlier mids as cancelled when a compound wait or MID
synchronization aborts. Keep their response buffers attached while the
MIDs are synchronized, and transfer them only after synchronization of
the processed responses, so the release path can inspect successful
CREATE responses and queue SMB2_close() after a later failure. Account for
a remote open only after the close work is allocated and before it is
queued, since the caller has not yet updated num_remote_opens. Mark the
create+close compound used by smb2_unlink() so it is not closed again.
Non-CREATE responses and compounds that already include a close keep their
existing behavior.
Fixes: e0bba0b854 ("cifs: add compound_send_recv()")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Assisted-by: LLM
Co-developed-by: Luxing Yin <root@tr0jan.top>
Signed-off-by: Luxing Yin <root@tr0jan.top>
Signed-off-by: Zihan Xi <zihanx@nebusec.ai>
Tested-by: Frank Sorenson <sorenson@redhat.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
open_cached_dir() sends CREATE and QUERY_INFO as a compound request. If
the CREATE succeeds but a later command returns an error, the function
must retain the CREATE FID so common cleanup can issue SMB2_close(). It
also must not treat a response error as a valid CREATE.
Validate the CREATE response before using its fields, record the FIDs, and
mark the handle open before handling errors from later compound commands.
Move the -EREMCHG reconnect handling before response validation so a
missing response does not hide the reconnect request. Count the handle
when it is marked open; confirmed close responses decrement the counter,
while existing close retry behavior remains best effort on transport
failures.
Fixes: b0f6df737a ("cifs: cache FILE_ALL_INFO for the shared root handle")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Assisted-by: LLM
Co-developed-by: Luxing Yin <root@tr0jan.top>
Signed-off-by: Luxing Yin <root@tr0jan.top>
Signed-off-by: Zihan Xi <zihanx@nebusec.ai>
Tested-by: Frank Sorenson <sorenson@redhat.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
SMB2_open() accounts a successful CREATE response as a remote open before
parsing its create contexts. If smb2_parse_contexts() rejects malformed
context data, SMB2_open() returns without closing the handle, leaving the
server-side handle open and num_remote_opens elevated.
Close the handle after a post-CREATE context parsing failure so the error
path releases the remote resource and balances the open count.
Fixes: af1689a9b7 ("smb: client: fix potential OOBs in smb2_parse_contexts()")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Assisted-by: LLM
Co-developed-by: Luxing Yin <root@tr0jan.top>
Signed-off-by: Luxing Yin <root@tr0jan.top>
Signed-off-by: Zihan Xi <zihanx@nebusec.ai>
Tested-by: Frank Sorenson <sorenson@redhat.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
parse_posix_ctxt() reads the fixed nlink, reparse_tag, and mode fields
before checking that the POSIX create context contains them. A short
context can pass the generic checks and still make these fixed-width
reads run past its declared data.
The current in-tree smb2_open_file() path passes a NULL posix pointer,
so this handler is not reached on the ordinary open path. Still require
the POSIX data to cover all three fields before reading them because the
helper performs those unguarded reads. Keep the existing soft-failure
behavior so malformed optional metadata does not fail the open.
Fixes: 69dda3059e ("cifs: add SMB2_open() arg to return POSIX data")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Assisted-by: LLM
Co-developed-by: Luxing Yin <root@tr0jan.top>
Signed-off-by: Luxing Yin <root@tr0jan.top>
Signed-off-by: Zihan Xi <zihanx@nebusec.ai>
Tested-by: Frank Sorenson <sorenson@redhat.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
smb2_parse_contexts() validates the complete create-context area but
does not limit each record to its Next field before dispatching it. A
malformed chain can therefore expose bytes beyond the current context to
a handler. The QFid handler also used a full response-structure cast
although it only reads DiskFileId.
The SMB2/SMB3 lease parsers made the same layout assumption: they read
LeaseState and LeaseFlags at canonical offsets rather than at
DataOffset. A valid non-canonical DataOffset could therefore yield
unrelated in-bounds data, while a short DataLength was still accepted.
Limit each context to its Next value, reject offsets before the context
header, and reject malformed chains. Bound the name range by the current
context and do not dispatch a known handler when DataLength is zero. Read
the QFid DiskFileId only when the context data covers that field. Parse the
lease context from DataOffset and require DataLength to match the v1 or v2
lease_context size used by ksmbd. A size mismatch skips lease parsing
without failing the open.
Fixes: b8c32dbb0d ("CIFS: Request SMB2.1 leases")
Fixes: f047390a09 ("CIFS: Add create lease v2 context for SMB3")
Fixes: 89a5bfa350 ("smb3: optimize open to not send query file internal info")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Assisted-by: LLM
Co-developed-by: Luxing Yin <root@tr0jan.top>
Signed-off-by: Luxing Yin <root@tr0jan.top>
Signed-off-by: Zihan Xi <zihanx@nebusec.ai>
Tested-by: Frank Sorenson <sorenson@redhat.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
When sending a compound request fails, smb_send_rqst() kicks off a
reconnect. compound_send_recv() still has those mids on pending_mid_q,
but it unlocks the server without removing them first.
During reconnect, cifs_abort_connection() walks pending_mid_q and runs
each mid callback. With no response yet, those callbacks return credits
and drop in_flight. Then compound_send_recv()'s send-error path returns
the same credits again. in_flight ends up decremented twice and
smb2_add_credits() WARNs.
syzbot hits this during SMB2_negotiate when the socket send fails.
cifs_call_async() already calls delete_mid() before unlock on send
failure. Do the same for compound chains and set cancelled_mid[] so the
out: path does not delete them again.
Fixes: ee258d7915 ("CIFS: Move credit processing to mid callbacks for SMB3")
Reported-by: syzbot+eeb58d2197d88720a228@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/r/6a727d22.40259c87.584f4.04ce.GAE@google.com
Tested-by: syzbot+eeb58d2197d88720a228@syzkaller.appspotmail.com
Assisted-by: LLM
Cc: stable@vger.kernel.org
Signed-off-by: Adarsh Das <adarshdas950@gmail.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
When a secondary channel is no longer supported by the server,
cifs_chan_skip_or_disable() drops the channel reference with
cifs_put_tcp_session() and then continues to use the server pointer by
calling cifs_signal_cifsd_for_reconnect() on it and reading its
primary_server pointer. cifs_put_tcp_session() can drop the last
reference of the channel and tear it down, so both the channel and the
primary server (whose reference is also dropped by
cifs_put_tcp_session()) can be freed before they are signaled for
reconnect.
Signal the channel and the primary server and capture the primary
server pointer before dropping the channel reference with
cifs_put_tcp_session().
Fixes: f591062bdb ("cifs: handle servers that still advertise multichannel after disabling")
Cc: stable@vger.kernel.org
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
In cifs_query_reparse_point(), the start >= end check before casting to
struct reparse_data_buffer * only ensures the start pointer is within the
response. It fails to verify that there is enough space remaining for the
fixed 8-byte header of the structure.
If a server provides a DataOffset that leaves less than 8 bytes remaining,
the check passes, but subsequent reads of ReparseTag and ReparseDataLength
will occur out-of-bounds.
Fix this by ensuring the remaining space is at least the size of the
reparse_data_buffer structure before accessing its fields.
Fixes: 56e84c64fc ("cifs: Fix validation of SMB1 query reparse point response")
Cc: stable@vger.kernel.org
Signed-off-by: Frank Sorenson <sorenson@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
If snapshot_array_size is smaller than GMT_TOKEN_SIZE,
smb3_enum_snapshots() sets ret_data_len to
sizeof(struct smb_snapshot_array) without verifying the actual length
of the server's reply.
Because SMB2_ioctl() places no lower bound on the server-supplied
OutputCount and allocates retbuf to exactly that length, a short reply
results in ret_data_len exceeding the size of retbuf. The subsequent
copy_to_user() then reads past the end of retbuf, leaking adjacent slab
memory to userspace. The subsequent clamp check is ineffective as it
only reduces ret_data_len.
Fix this by rejecting replies shorter than
sizeof(struct smb_snapshot_array) with -EIO. Note that the bound is set
to the 12-byte struct size rather than the 16-byte
MIN_SNAPSHOT_ARRAY_SIZE defined in MS-SMB2 3.3.5.15.1, because 12 bytes
is exactly what copy_to_user() attempts to read.
Fixes: e02789a53d ("smb3: enumerating snapshots was leaving part of the data off end")
Cc: stable@vger.kernel.org
Signed-off-by: Frank Sorenson <sorenson@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
In parse_posix_sids(), sidsbuf_end is calculated using the server-supplied
out_len without being validated against the actual length of the received
iov (iov_len).
If a server provides an inflated out_len, sidsbuf_end will point past the
end of the iov. This defeats the bounds guards in posix_info_sid_size(),
allowing out-of-bounds reads into adjacent kernel memory.
Fix this by rejecting responses where the calculated sidsbuf_end would
exceed the received iov boundaries or cause pointer wraparound.
Fixes: a90f37e3d7ac ("smb: client: parse owner/group when creating reparse points")
Cc: stable@vger.kernel.org
Signed-off-by: Frank Sorenson <sorenson@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
In move_smb2_ea_to_cifs(), the while (src_size > 0) loop condition is
insufficient. It allows iteration to continue even if the remaining
src_size is too small to contain a complete smb2_ea_info structure.
Consequently, reads of ea_name_length and ea_value_length can occur
out-of-bounds.
Fix this by ensuring src_size >= sizeof(*src) before attempting to read
any structure fields. Additionally, reject any next_entry_offset that is
smaller than sizeof(*src) or that would advance the pointer beyond the
available buffer.
Note that for calls where the server returns a malformed EA list, the
error returned to userspace changes from -ENODATA (getxattr) or
-ERANGE (listxattr) to -EIO. This correctly signals a server protocol
error rather than misleadingly indicating "attribute not present" or
"output buffer too small".
Fixes: 95907fea4f ("cifs: Add support for reading attributes on SMB2+")
Cc: stable@vger.kernel.org
Signed-off-by: Frank Sorenson <sorenson@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
In parse_server_interfaces(), the server-supplied Next offset is
validated against bytes_left, but not against the size of the interface
structure itself.
A small, non-zero Next value can pass the bounds check but advance the
pointer by less than sizeof(*p). This causes the next iteration of the
loop to read misaligned, overlapping structure fields.
Fix this by ensuring the Next offset is at least sizeof(*p).
Fixes: 7d34ec36ab ("smb3: fix for slab out of bounds on mount to ksmbd")
Cc: stable@vger.kernel.org
Signed-off-by: Frank Sorenson <sorenson@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
parse_dfs_referrals() checks that DfsPathOffset and NetworkAddressOffset
do not exceed the buffer end, but fails to check that they don't point
inside the referral header itself.
If a server provides an offset smaller than
sizeof(struct dfs_referral_level_3), the derived string pointer overlaps
with the struct fields, causing cifs_strndup_from_utf16() to interpret
header data as UTF-16 strings.
Fix this by enforcing that string offsets are at least sizeof(*ref).
Fixes: 4ecce920e1 ("CIFS: move DFS response parsing out of SMB1 code")
Cc: stable@vger.kernel.org
Signed-off-by: Frank Sorenson <sorenson@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
In receive_encrypted_standard(), server->total_read is left at the
full decrypted frame size when walking sub-PDUs of a compound encrypted
frame. As a result, cifs_handle_standard() passes this full size
to smb2_check_message(), causing the PDU length guards to incorrectly
validate the entire compound frame instead of the current sub-PDU.
This allows truncated non-last sub-PDUs to bypass length validation,
leading to out-of-bounds reads in smb2_get_data_area_len().
Fix this by setting server->total_read to the true length of the
current sub-PDU: next_cmd for non-last sub-PDUs, and the remaining
pdu_length for the last one.
Fixes: b24df3e30c ("cifs: update receive_encrypted_standard to handle compounded responses")
Cc: stable@vger.kernel.org
Signed-off-by: Frank Sorenson <sorenson@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
__smb2_calc_size() calls smb2_get_data_area_len(), which reads
command-specific struct fields to locate the data area. However,
smb2_check_message() only validates StructureSize2, meaning a truncated
response could cause smb2_get_data_area_len() to read out-of-bounds.
Replace has_smb2_data_area[] with smb2_min_pdu_len[], which is now
used to indicate both whether a command's response has a data area
and the size of that fixed response struct. A non-zero entry means
the command has a data area, and is the minimum length required
before the struct is read.
For each command with a data area, PDUs shorter than this minimum size
are rejected instead of parsed.
The minimum is not applied to SMB2 error responses, which carry only
the 9-byte error body, the same exemption the StructureSize2 check
above it already makes. STATUS_MORE_PROCESSING_REQUIRED is
treated as a normal reply, since an in-progress SESSION_SETUP
response carries a full body and a security blob.
Signed-off-by: Frank Sorenson <sorenson@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Fix several related bounds checking and pointer lifecycle issues in
receive_encrypted_standard()'s handling of compound encrypted frames:
- Clear next_buffer after assigning it to server->bigbuf. A stale
next_buffer pointer can lead to a use-after-free on subsequent
error paths.
- Update pdu_length to the decrypted plaintext size (buf_size). Using
the pre-decryption length allows NextCommand to point into stale
ciphertext residue.
- Reject next_cmd values smaller than MID_HEADER_SIZE(server).
- Fix an integer overflow in the upper bound check by verifying
pdu_length - next_cmd < MID_HEADER_SIZE(server), ensuring the
trailing slice is large enough for a header.
Fixes: b24df3e30c ("cifs: update receive_encrypted_standard to handle compounded responses")
Cc: stable@vger.kernel.org
Signed-off-by: Frank Sorenson <sorenson@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
cifs_try_adding_channels() iterates ses->iface_list with
list_for_each_entry_safe_from(), which captures the next entry
(niface) under iface_lock. The loop body then drops iface_lock for
the whole duration of cifs_ses_add_channel().
A concurrent interface refresh (SMB3_request_interfaces() ->
parse_server_interfaces()) marks all ifaces inactive and removes and
frees any that are not re-advertised via list_del() + kref_put(),
where release_iface() is a bare kfree(). Since niface typically has
no channel holding a reference, the list reference is its last and it
can be freed inside the unlocked window. On continue, the iterator
advance step then dereferences niface->iface_head.next, and the loop
body reads iface->rdma_capable/is_active, both on freed memory.
Fix this by never keeping an unreferenced list pointer across the
unlocked window. Each channel attempt now re-scans the list from the
head under iface_lock, takes a kref on the selected candidate, and
passes only that referenced candidate to cifs_ses_add_channel().
weight_fulfilled still tracks selection progress, so restarting the
scan preserves the original weighted distribution and the
weight_fulfilled-before-kref_put ordering on the failure path.
Add a per-pass attempts cap so a flapping interface refresh cannot
keep the inner loop spinning within a single tries increment.
Fixes: aa45dadd34 ("cifs: change iface_list from array to sorted linked list")
Cc: stable@vger.kernel.org
Assisted-by: Qoder:Qwen3.8-Max
Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Acked-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
wsl_to_fattr() mutates fattr fields as it parses each WSL EA. If
validation later fails, the function returns false with partially
mutated fattr fields that callers do not reset.
Fix this by parsing into local variables and only committing them to
fattr on success.
Closes: https://sashiko.dev/#/patchset/20260906200517.725015-1-pc%40manguebit.org
Fixes: 78e26bec4d ("smb: client: parse uid, gid, mode and dev from WSL reparse points")
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: stable@vger.kernel.org
When wsl_to_fattr() parses WSL extended attributes, it computes a
payload pointer from ea->ea_data + ea_name_length + 1. Since the
smb2_file_full_ea_info struct is __packed and all WSL xattr names are
6 bytes long, the value pointer always lands at an odd byte offset,
never satisfying __le32 or __le64 alignment requirements.
The code then casts this pointer to __le32 * or __le64 * and
dereferences it directly, which may cause alignment faults on some
architectures.
Replace all such casts with get_unaligned_le32() and
get_unaligned_le64() in reparse_mkdev(), wsl_make_kuid(),
wsl_make_kgid() and wsl_to_fattr().
Closes: https://sashiko.dev/#/patchset/20260906200517.725015-1-pc%40manguebit.org
Fixes: 78e26bec4d ("smb: client: parse uid, gid, mode and dev from WSL reparse points")
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: stable@vger.kernel.org
When an RDMA connection is successfully established via
smbd_get_connection() but cifs_get_tcp_session() later fails (e.g.
kthread_create() returns an error), the error path frees tcp_ses
without first destroying the smbd_connection.
Fix this by calling smbd_destroy() in the out_err cleanup path before
kfree(tcp_ses). smbd_destroy() safely handles the case where
smbd_conn is NULL, so it can be called unconditionally.
Closes: https://sashiko.dev/#/patchset/20260912165503.521597-1-pc%40manguebit.org
Fixes: 2f8946464b ("CIFS: SMBD: Upper layer connects to SMBDirect session")
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Tom Talpey <tom@talpey.com>
Cc: Stefan Metzmacher <metze@samba.org>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: stable@vger.kernel.org
TCP_Server_Info.rlist is allocated via kzalloc which zeros both ->next
and ->prev to NULL instead of pointing to itself, making list_empty()
always return false and list_add() dereference a NULL ->prev pointer.
Also, cifs_signal_cifsd_for_reconnect() can be called concurrently
from multiple cifsd threads, allowing the same server's rlist node to
be added twice into the local list, corrupting it.
Closes: https://sashiko.dev/#/patchset/20260911204446.1719356-1-pc%40manguebit.org
Fixes: df0e03a4fb94 ("smb: client: fix potential deadlock when reconnecting channels")
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: stable@vger.kernel.org
clean_demultiplex_info() cancels server->echo delayed work but not
server->reconnect, which can cause a use-after-free when the
demultiplex thread exits while a reconnect work is still queued:
cifs_demultiplex_thread()
cifs_readv_from_socket()
cifs_reconnect()
__cifs_reconnect()
cifs_queue_server_reconn()
mod_delayed_work(cifsiod_wq, &server->reconnect, 0)
clean_demultiplex_info()
cancel_delayed_work_sync(&server->echo) // echo canceled
// reconnect NOT canceled
kfree_sensitive(server) // server freed
...later, on cifsiod_wq:
smb2_reconnect_server()
server->srv_count // UAF read of freed server
Fix this by canceling server->reconnect delayed work in
clean_demultiplex_info() before the server is freed, the same way
cifs_put_tcp_session() already does.
Reported-by: syzbot+5003556314abc915a71f@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/r/6aa4a12d.f81106d8.2ab401.0023.GAE@google.com
Fixes: 53e0e11efe ("CIFS: Fix a possible memory corruption during reconnect")
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: stable@vger.kernel.org
Currently, when cifs_oplock_break handles a break request from the server
it searches for the appropriate tlink to handle the request
but incorrectly uses the current fsuid as the search key, eventually
causing read errors for users with multiuser mounts on NetApp.
Fix this by using the tlink from the cfile struct instead to respond
through the correct session.
As breaks are handled in a worker thread, the current fsuid
isn't guaranteed to match the session that the break is intended for.
This means that cifs_sb_tlink may search the rbtree using the wrong fsuid,
and return a tlink with an incorrect session than
the lease break was intended for. As a result, the breaks
may be ACKed through an incorrect session.
While it seems that Samba/Windows Servers 2016-2025 ignore this as long as
the lease key is correct, we ran into a case where if you're using
NetApp ONTAP or Azure NetApp Files they will reject the ACK
and return `STATUS_LOCK_NOT_GRANTED` errors on any future read requests
a user may initiate through their still held open file handle,
and the server will eventually close the file.
In the dmesg logs, the user may see errors like these:
CIFS: Status code returned 0xc0000128 STATUS_FILE_CLOSED
CIFS: VFS: Send error in read = -9
With a multiuser mount using NetApp, this issue is really easy
for users to hit on a wide variety of kernel versions
by attempting to copy a file from the share
to the local machine through GNOME Files/Nautilus.
This copy will always result in Nautilus throwing
a `Bad File Descriptor` error to the user and fail.
With this fix, you can copy files through Nautilus without issue.
>From looking at the traces, it seems that glib will
open the file first, and call listxattr before actually attempting
to copy the file data. The listxattr call always triggers a break,
causing the copy to fail.
The proposed fix returns to the way the client grabbed the tlink before
commit e8f5f849ff ("cifs: fix potential oops in cifs_oplock_break").
The bulk of that commit (checking for list empty) remains untouched, and
I think the change to using cifs_sb_tlink was intended to avoid a
NULL/ERR deference on the tlink as well as update the reference count.
I believe this fix should preserve those safety properties, but of course
I'd appreciate any corrections here.
Fixes: e8f5f849ff ("cifs: fix potential oops in cifs_oplock_break")
Cc: stable@vger.kernel.org
Signed-off-by: April Cardenas <april.cardenas@canonical.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Reviewed-by: Bharath S M <bharathsm@microsoft.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
With symlinkroot unset, an absolute target is copied without conversion
to an NT drive path. Later code still assumes an NT prefix is present
when modifying the target and calculating the print name length.
For "/ab", this causes two failures: sym[5] and path[5] are written
past their allocations, and plen -= 2 * poff subtracts an assumed
8-byte prefix from a 6-byte UTF-16 target, wrapping u16 plen to 65534.
That underflow causes another overflow: memcpy() copies 65534 bytes
into a 24-byte buffer. A user with write access to a mounted share
can trigger these bugs with default settings.
Validate the NT drive prefix, including an ASCII drive letter, before
accessing fixed offsets or subtracting the prefix length.
Fixes: 3363da82e0 ("smb: client: fix native SMB symlink traversal")
Assisted-by: Codex:gpt-5
Signed-off-by: Jérémy Jean <Jeremy.Jean@oss.cyber.gouv.fr>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
A batch of bug fixes for the smb client:
- File type corruption fixes in reparse point handling: setting S_IFMT
bits without clearing the existing type first corrupted the file mode
(e.g. S_IFREG | S_IFCHR == S_IFLNK). Fixed in the WSL, POSIX and
native symlink reparse parsers. Also fixes an uninitialized SID
structure in the POSIX readdir path when parsing fails.
- Ownership mapping fixes: forceuid/forcegid mount options were
ignored in several code paths (SID-to-id mapping, WSL extended
attributes, POSIX extensions getattr), allowing an untrusted server
to dictate local file ownership despite explicit mount overrides.
- Heap overflow and overflow fixes in DACL rewriting: replacing short
SIDs with long ones could overflow the DACL buffer, and the u16
accumulator for DACL size could wrap around with enough ACEs.
- Reference count leak fixes in oplock break and deferred close:
duplicate oplock breaks on a queued work item leaked a
cifsFileInfo reference, and deferred close had a similar leak when
requeueing a running work item. Both cause busy-inode oopses on
unmount.
- DFS superblock use-after-free fix: the iterator callback stored a
raw superblock pointer without pinning it, racing with automount
expiry.
- One-byte slab OOB read in the native symlink parser when handling
share-root relative paths.
- Hardening of legacy SMB1 input: reject userspace-crafted
cifs.idmap key descriptions that bypass kernel origin checks, and
validate DataOffset in CIFSSMBRead() to prevent heap info
disclosure from a malicious server.
- DFS cache fix: defer metadata updates until target copying
succeeds to prevent partial-state cache entries on allocation
failure.
-----BEGIN PGP SIGNATURE-----
iHUEABYKAB0WIQTcqRusfSdYROJQwGkpVtNKoQNdYwUCaqLMxAAKCRApVtNKoQNd
YwSyAQDUDSxCnDMmJbRr4e22oF/YrGSN/snp8cqrZlZh2pb5/gD/c2G3xMJA85YP
yL/G8auRWkpwDl0/Parqptjhx1c9YwE=
=PjPM
-----END PGP SIGNATURE-----
Merge tag 'cifs-fixes-7.3-rc3' of https://git.manguebit.org/linux
Pull smb client fixes from Paulo Alcantara:
- File type corruption fixes in reparse point handling: setting S_IFMT
bits without clearing the existing type first corrupted the file mode
(e.g. S_IFREG | S_IFCHR == S_IFLNK). Fixed in the WSL, POSIX and
native symlink reparse parsers. Also fixes an uninitialized SID
structure in the POSIX readdir path when parsing fails.
- Ownership mapping fixes: forceuid/forcegid mount options were
ignored in several code paths (SID-to-id mapping, WSL extended
attributes, POSIX extensions getattr), allowing an untrusted server
to dictate local file ownership despite explicit mount overrides.
- Heap overflow and overflow fixes in DACL rewriting: replacing short
SIDs with long ones could overflow the DACL buffer, and the u16
accumulator for DACL size could wrap around with enough ACEs.
- Reference count leak fixes in oplock break and deferred close:
duplicate oplock breaks on a queued work item leaked a
cifsFileInfo reference, and deferred close had a similar leak when
requeueing a running work item. Both cause busy-inode oopses on
unmount.
- DFS superblock use-after-free fix: the iterator callback stored a
raw superblock pointer without pinning it, racing with automount
expiry.
- One-byte slab OOB read in the native symlink parser when handling
share-root relative paths.
- Hardening of legacy SMB1 input: reject userspace-crafted
cifs.idmap key descriptions that bypass kernel origin checks, and
validate DataOffset in CIFSSMBRead() to prevent heap info
disclosure from a malicious server.
- DFS cache fix: defer metadata updates until target copying
succeeds to prevent partial-state cache entries on allocation
failure.
* tag 'cifs-fixes-7.3-rc3' of https://git.manguebit.org/linux:
smb: client: fix one-byte OOB read in smb2_parse_native_symlink()
smb: client: fail DACL rewrite when the new DACL exceeds 64K
smb: client: fix heap overflow in DACL owner/group rewrite
smb: client: fix file type corruption in cifs_reparse_point_to_fattr()
smb: client: fix file type corruption in posix_reparse_to_fattr()
smb: client: fix file type corruption in wsl_to_fattr()
smb: client: avoid using uninitialized SIDs in cifs_posix_to_fattr()
smb: client: fix WSL reparse point uid/gid override
smb: client: honor forceuid/forcegid when mapping SIDs to uid/gid
smb: client: fix uid/gid override in getattr with posix extensions
smb: client: fix cifsFileInfo reference leak in deferred close
smb: client: avoid leaking refcount when cifs_sb_tlink() fails
smb: client: avoid leaking refcount in cifs_queue_oplock_break()
smb: client: fill cache fields after populating cache in copy_ref_data()
smb: client: pin DFS superblock in iterator callback
smb: client: reject userspace cifs.idmap descriptions
smb: client: reject out-of-bounds DataOffset in CIFSSMBRead()
smb: client: reject short READ responses in CIFSSMBRead()
When parsing a share-root relative native symlink, memcpy copies
smb_target+1 (skipping the leading separator) but uses
strlen(smb_target)+1 as the length, reading one byte past the
allocated buffer.
This fixes the following KASAN splat when accessing an SMB symlink
with a target of '\a\b':
BUG: KASAN: slab-out-of-bounds in smb2_parse_native_symlink+0x4f5/0xca0
Read of size 5 at addr ffff88800878fe21 by task netfsfuzz-execu/1
CPU: 1 UID: 0 PID: 1 Comm: netfsfuzz-execu Tainted: G N
7.2.0-11943-g2709dd5ae32f-dirty #1 PREEMPT(lazy)
Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix,
1996)
Call Trace:
<TASK>
dump_stack_lvl+0x7b/0xa0
print_report+0xd0/0x630
kasan_report+0xe5/0x120
kasan_check_range+0x105/0x1b0
__asan_memcpy+0x23/0x60
smb2_parse_native_symlink+0x4f5/0xca0
parse_reparse_point+0x68a/0x1530
reparse_info_to_fattr+0x752/0xa20
cifs_get_fattr+0x873/0x15b0
cifs_get_inode_info+0xc0/0x310
cifs_lookup+0x308/0xa70
__lookup_slow+0x122/0x2b0
lookup_slow+0x50/0x70
path_lookupat+0x525/0xaf0
filename_lookup+0x1f2/0x550
vfs_statx+0xd1/0x1a0
vfs_fstatat+0x65/0xc0
__do_sys_newfstatat+0x9a/0x120
do_syscall_64+0xdd/0x4a0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Reported-by: Yuanfu Xie <yuanfuxie@stu.pku.edu.cn>
Fixes: 723f4ef904 ("cifs: Fix parsing native symlinks relative to the export")
Suggested-by: Pali Rohar <pali@kernel.org>
Reviewed-by: Pali Rohar <pali@kernel.org>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
replace_sids_and_copy_aces() and set_chmod_dacl() accumulate the size of
the DACL they build in a u16. That accumulator can wrap.
validate_dacl() caps num_aces at (dacl_size - sizeof(struct smb_acl)) /
20, i.e. 3276 for a maximally sized DACL, while each rewritten ACE can
grow to sizeof(struct smb_ace) (76 bytes) once its SID is replaced with
one carrying SID_MAX_SUB_AUTHORITIES sub-authorities. The worst case is
therefore sizeof(struct smb_acl) + 3276 * 76 = 248984 bytes, far beyond
what a u16 can hold. A wraparound is reached with 863 ACEs.
After the wraparound, ndacl_ptr->size becomes meaningless and the offset
will point anywhere in the ACE array. As a result, we will see
corruption of the DACL, which then gets sent to the server. This is not
an out-of-bounds write as the allocation now covers the worst-case
expansion, so writes will always go into the buffer.
Adjust the code to use a u32 internally and return -EOVERFLOW in the
overflow case. The operation must be refused, because a DACL can only
hold 2^16-1 bytes on the wire and larger DACLs cannot be represented.
set_chmod_dacl() carries the same pattern and is fixed the same way. It
only wraps once the source DACL comes within roughly 380 bytes of the
64K ceiling, but the failure mode is identical.
Suggested-by: Namjae Jeon <linkinjeon@kernel.org>
Cc: stable@vger.kernel.org
Fixes: f506550889 ("cifs: Retain old ACEs when converting between mode bits and ACL.")
Assisted-by: Kiro:claude-opus-5
Signed-off-by: Bjoern Doebel <doebel@amazon.de>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
When id_mode_to_cifs_acl rewrites an existing DACL, it allocates a
buffer sized according to the on-disk DACL length reported by
dacl_ptr->size. However, replace_sids_and_copy_aces may rewrite each
ACE with a new owner/group SID obtained from the cifs.idmap upcall.
Those SIDs can have up to SID_MAX_SUB_AUTHORITIES (15) sub-authorities,
making each ACE up to 76 bytes (sizeof(struct smb_ace)).
If the original DACL contains short SIDs (e.g., 1 sub-authority) while
the replacement SIDs are long, the rewritten ACEs overflow the
allocation.
Fix this by always budgeting for worst-case SID expansion: allocate
sizeof(struct smb_acl) plus num_aces * sizeof(struct smb_ace), which
covers the smb_acl header and room for every ACE at maximum SID size.
This replaces the previous split logic that used dacl_ptr->size for
cifsacl mounts but num_aces * sizeof(struct smb_ace) for mode_from_sid
mounts: both paths can trigger the same rewrite and need the same
headroom.
KASAN reports this as:
BUG: KASAN: slab-out-of-bounds in build_sec_desc+0x1e8a/0x2680 [cifs]
Write of size 4 at addr ffff8881a5e25374 by task chown/5298
...
The buggy address is located 0 bytes to the right of
allocated 884-byte region [ffff8881a5e25000, ffff8881a5e25374)
Cc: stable@vger.kernel.org
Fixes: bc3e9dd9d1 ("cifs: Change SIDs in ACEs while transferring file ownership.")
Assisted-by: Kiro:claude-opus-4.6
Signed-off-by: Bjoern Doebel <doebel@amazon.de>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Fixes: 5c3564852c58 ("cifs: Minimize the number of cifs_acl memory allocations")
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Setting the file type in cf_mode without clearing the existing S_IFMT
bits first is wrong as it corrupts the file type when cf_mode already
has type bits set (e.g. S_IFREG | S_IFLNK == S_IFDIR | S_IFREG).
Clear S_IFMT before setting S_IFLNK for native and SMB1 symlinks.
Closes: https://sashiko.dev/#/patchset/20260906181540.647469-1-pc%40manguebit.org
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
Setting the file type in cf_mode without clearing the existing S_IFMT
bits first is wrong as it corrupts the file type when cf_mode already
has type bits set (e.g. S_IFREG | S_IFCHR == S_IFLNK).
Use a local ftype variable to collect the new file type and apply it
after validation succeeds, clearing S_IFMT and setting the new type in
a single assignment. This avoids stripping cf_mode on malformed
reparse points where the function returns false early.
Closes: https://sashiko.dev/#/patchset/20260906172005.627163-1-pc%40manguebit.org
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
Setting the file type in cf_mode without clearing the existing S_IFMT
bits first is wrong as it corrupts the file type when cf_mode already
has type bits set (e.g. S_IFREG | S_IFCHR == S_IFLNK).
Clear S_IFMT before the switch statement.
Closes: https://sashiko.dev/#/patchset/20260906172005.627163-1-pc%40manguebit.org
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
cifs_posix_to_fattr() ignores the return value of posix_info_parse().
When a malformed POSIX directory entry is encountered (e.g. invalid
SID lengths from an untrusted server), posix_info_parse() returns -1
without populating the 'parsed' struct. The uninitialized stack
memory in parsed.owner and parsed.group is then passed to
sid_to_id(), which processes the garbage bytes and passes them to
request_key() to construct a SID string, potentially leaking kernel
stack contents to the userspace idmap daemon.
Fix this by checking the return value and skipping the SID-to-id
mapping when parsing fails. The remaining fattr fields (timestamps,
mode, etc.) are populated directly from the 'info' pointer so they
are unaffected.
Closes: https://sashiko.dev/#/patchset/20260906172005.627163-1-pc%40manguebit.org
Closes: https://sashiko.dev/#/patchset/20260906181540.647469-1-pc%40manguebit.org
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
wsl_to_fattr() unconditionally overwrites cf_uid/cf_gid with values
from WSL extended attributes ($LXUID/$LXGID), ignoring the forceuid
and forcegid mount options.
Fix this by initializing cf_uid/cf_gid to the mount defaults and
gating the $LXUID/$LXGID EA parsing on forceuid/forcegid.
Closes: https://sashiko.dev/#/patchset/20260906190803.667489-1-pc%40manguebit.org
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
