Pull dcache updates from Al Viro:
- d_alloc_parallel() API change (Neil's with my changes)
- NORCU fixes
- Reorganization and simplification of dentry eviction logic
- Simplifying rcu_read_lock() scopes in fs/dcache.c
- Secondary roots work - getting rid of NFS fake root dentries and
dealing with remaining shrink_dcache_for_umount() and
shrink_dentry_list() races
- making cursors NORCU (surprisingly easy)
* tag 'pull-dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (22 commits)
make cursors NORCU
nfs: get rid of fake root dentries
wind ->s_roots via ->d_sib instead of ->d_hash
shrink_dentry_tree(): unify the calls of shrink_dentry_list()
shrinking rcu_read_lock() scope in d_alloc_parallel()
d_walk(): shrink rcu_read_lock() scope
document dentry_kill()
adjust calling conventions of lock_for_kill(), fold __dentry_kill() into dentry_kill()
Document rcu_read_lock() use in select_collect2()
Shift rcu_read_{,un}lock() inside fast_dput()
simplify safety for lock_for_kill() slowpath
fold lock_for_kill() and __dentry_kill() into common helper
fold lock_for_kill() into shrink_kill()
shrink_dentry_list(): start with removing from shrink list
d_prune_aliases(): make sure to skip NORCU aliases
kill d_dispose_if_unused()
make to_shrink_list() return whether it has moved dentry to list
select_collect(): ignore dentries on shrink lists if they have positive refcounts
find_acceptable_alias(): skip NORCU aliases with zero refcount
fix a race between d_find_any_alias() and final dput() of NORCU dentries
...
Pull vfs superblock updates from Christian Brauner:
"This retires sget().
CIFS plus the two ext4 KUnit tests (extents-test, mballoc-test) were
the last in-tree callers, and all three convert cleanly to sget_fc().
That lets sget() and its prototype come out, taking ~60 lines that
only existed to be kept in lockstep with sget_fc() on every
publish-path change"
* tag 'vfs-7.2-rc1.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
fs: retire sget()
smb: client: convert cifs_smb3_do_mount() to sget_fc()
ext4: convert mballoc KUnit test to sget_fc()
ext4: convert extents KUnit test to sget_fc()
Pull openat2 updates from Christian Brauner:
"Features:
- Add O_EMPTYPATH to openat(2)/openat2(2). To get an operable file
descriptor from an O_PATH file descriptor it is possible to use
openat(fd, ".", O_DIRECTORY) for directories, but other file types
require going through open("/proc/<pid>/fd/<nr>") and thus depend
on a functioning procfs.
With O_EMPTYPATH an empty path string is accepted and LOOKUP_EMPTY
is set at path resolution time, allowing to reopen the file behind
the file descriptor directly. Selftests are included.
- Add an OPENAT2_REGULAR flag for openat2(2) which refuses to open
anything but regular files with the new EFTYPE error code.
This implements the "ability to only open regular files" feature
requested by userspace via uapi-group.org and protects services
from being redirected to fifos, device nodes, and friends.
All atomic_open implementations were audited for OPENAT2_REGULAR
handling. Explicit checks were added to ceph, gfs2, nfs (v4), and
cifs/smb - these are the filesystems whose atomic_open can
encounter an existing non-regular file and would otherwise call
finish_open() on it or return a misleading error code.
The remaining implementations (9p, fuse, vboxsf, nfs v2/v3) only
call finish_open() on freshly created files and use
finish_no_open() for lookup hits, letting the VFS catch non-regular
files via the do_open() safety net.
Cleanups:
- Migrate the openat2 selftests to the kselftest harness and move
them under selftests/filesystems/. The tests were written in the
early days of selftests' TAP support and the modern kselftest
harness is much easier to follow and maintain. The contents of the
tests are unchanged and the new emptypath tests are ported on top.
- Make the LAST_XXX last-type constants private to fs/namei.c. The
only user outside of fs/namei.c was ksmbd which only needs to know
whether the last component is a regular one, so
vfs_path_parent_lookup() now performs the LAST_NORM check
internally. The ints are replaced with a dedicated enum last_type"
* tag 'vfs-7.2-rc1.openat2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
vfs: replace ints with enum last_type for LAST_XXX
vfs: make LAST_XXX private to fs/namei.c
selftests: openat2: port emptypath_test to kselftest harness
kselftest/openat2: test for OPENAT2_REGULAR flag
openat2: new OPENAT2_REGULAR flag support
openat2: introduce EFTYPE error code
selftest: add tests for O_EMPTYPATH
vfs: add O_EMPTYPATH to openat(2)/openat2(2)
selftests: openat2: migrate to kselftest harness
selftests: openat2: switch from custom ARRAY_LEN to ARRAY_SIZE
selftests: openat2: move helpers to header
selftests: move openat2 tests to selftests/filesystems/
Pull vfs casefolding updates from Christian Brauner:
"This exposes the case folding behavior of local filesystems so that
file servers - nfsd, ksmbd, and user space file servers - can report
the actual behavior to clients instead of guessing.
Filesystems report case-insensitive and case-nonpreserving behavior
via new file_kattr flags in their fileattr_get implementations. fat,
exfat, ntfs3, hfs, hfsplus, xfs, cifs, nfs, vboxsf, and isofs are
wired up. Local filesystems that are not explicitly handled default to
the usual POSIX behavior of case-sensitive and case-preserving.
nfsd uses this to report case folding via NFSv3 PATHCONF and to
implement the NFSv4 FATTR4_CASE_INSENSITIVE and FATTR4_CASE_PRESERVING
attributes - both have been part of the NFS protocols for decades to
support clients on non-POSIX systems - and ksmbd reports it via
FS_ATTRIBUTE_INFORMATION. Exposing the information through the
fileattr uapi covers user space file servers.
The immediate motivation is interoperability: Windows NFS clients
hard-require servers to report case-insensitivity for Win32
applications to work correctly, and a client that knows the server is
case-insensitive can avoid issuing multiple LOOKUP/READDIR requests
searching for case variants.
The Linux NFS client already grew support for case-insensitive shares
years ago in support of the Hammerspace NFS server - negative dentry
caching must be disabled (a lookup for "FILE.TXT" failing must not
cache a negative entry when "file.txt" exists) and directory change
invalidation must drop cached case-folded name variants. Such servers
often operate in multi-protocol environments where a single file
service instance caters to both NFS and SMB clients, and nfsd needs to
report case folding properly to participate as a first-class citizen
there.
A follow-up series brings fixes for the initial work: the nfsd
case-info probe now uses kernel credentials, maps -ESTALE to
NFS3ERR_STALE, and has its cost capped across READDIR entries; the nfs
client avoids transiently zeroed case capability bits during the probe
and skips the pathconf probe when neither field is consumed; the
FS_CASEFOLD_FL semantics are clarified in the UAPI header; and the
tools UAPI headers are synced"
* tag 'vfs-7.2-rc1.casefold' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (22 commits)
nfsd: Cap case-folding probe cost across READDIR entries
nfsd: Map -ESTALE from case probe to NFS3ERR_STALE
nfsd: Use kernel credentials for case-info probe
fs: Clarify FS_CASEFOLD_FL semantics in UAPI header
nfs: Skip pathconf probe when neither field is consumed
nfs: Avoid transient zeroed case capability bits during probe
tools headers UAPI: Sync case-sensitivity flags from linux/fs.h
ksmbd: Report filesystem case sensitivity via FS_ATTRIBUTE_INFORMATION
nfsd: Implement NFSv4 FATTR4_CASE_INSENSITIVE and FATTR4_CASE_PRESERVING
nfsd: Report export case-folding via NFSv3 PATHCONF
isofs: Implement fileattr_get for case sensitivity
vboxsf: Implement fileattr_get for case sensitivity
nfs: Implement fileattr_get for case sensitivity
cifs: Implement fileattr_get for case sensitivity
xfs: Report case sensitivity in fileattr_get
hfsplus: Report case sensitivity in fileattr_get
hfs: Implement fileattr_get for case sensitivity
ntfs3: Implement fileattr_get for case sensitivity
exfat: Implement fileattr_get for case sensitivity
fat: Implement fileattr_get for case sensitivity
...
Pull vfs inode updates from Christian Brauner:
"This extends the lockless ->i_count handling.
iput() could already decrement any value greater than one locklessly
but acquiring a reference always required taking inode->i_lock. Now
acquiring a reference is lockless as long as the count was already at
least 1, i.e., only the 0->1 and 1->0 transitions take the lock.
This avoids the lock for the common cases of nfs calling into the
inode hash and btrfs using igrab(). Cleanup-wise icount_read_once() is
added to line up with inode_state_read_once() and the open-coded
->i_count loads across the tree are converted, and ihold() is
relocated and tidied up.
On top of that some stale lock ordering annotations are retired from
the inode hash code: iunique() no longer takes the hash lock since the
inode hash became RCU-searchable and s_inode_list_lock is no longer
taken under the hash lock either"
* tag 'vfs-7.2-rc1.inode' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
fs: retire stale lock ordering annotations from inode hash
fs: allow lockless ->i_count bumps as long as it does not transition 0->1
fs: relocate and tidy up ihold()
fs: add icount_read_once() and stop open-coding ->i_count loads
Parallel lookup starts with a call of d_alloc_parallel(). That primitive
either returns a matching hashed dentry or allocates a new one in the
in-lookup state and returns it to the caller. Once the caller is done
with lookup, it indicates so either by call of d_{splice_alias,add}()
or by call of d_done_lookup(); at that point dentry leaves the in-lookup
state.
If d_alloc_parallel() finds a matching in-lookup dentry, it must wait for
that dentry to leave the in-lookup state, one way or another. Currently
by supplying wait_queue_head to d_alloc_parallel(). If d_alloc_parallel()
creates a new in-lookup dentry, the address of that wait_queue_head is stored
in ->d_wait of new dentry and stays there while it's in the in-lookup;
subsequent d_alloc_parallel() will wait on the queue found in the matching
in-lookup dentry. Transition out of in-lookup state wakes waiters on that
queue (if any).
That works, but the calling conventions are inconvenient - the caller must
supply wait_queue_head and make sure that it survives at least until the new
in-lookup dentry leaves the in-lookup state. That amounts to boilerplate
in the d_alloc_parallel() callers that are followed by a call of d_lookup_done()
in the same function; in cases like nfs asynchronous unlink it gets worse than
that.
This patch changes d_alloc_parallel() to use wake_up_var_locked() to
wake up waiters, and wait_var_event_spinlock() to wait. dentry->d_lock
is used for synchronisation as it is already held and the relevant
times.
That eliminates the need of caller-supplied wait_queue_head, simplifying
the calling conventions. Better yet, we only need one bit of information
stored in dentry itself: whether there are any waiters to be woken up,
and that can be easily stored in ->d_flags; ->d_wait goes away.
The reason we need that bit (DCACHE_LOOKUP_WAITERS) is that with wait_var
machinery the queues are shared with all kinds of stuff and there's
no way tell if any of the waiters have anything to do with our dentry;
most of the time none of them will be relevant, so we need to avoid the
pointless wakeups.
Another benefit of the new scheme comes from the fact that wakeups
have to be done outside of write-side critical areas of ->i_dir_seq;
with the old scheme we need to carry the value picked from ->d_wait from
__d_lookup_unhash() to the place where we actually wake the waiters up.
Now we can just leave DCACHE_LOOKUP_WAITERS in ->d_flags until we get
to doing wakeups - that's done within the same ->d_lock scope, so we
are fine; new bit is accessed only under ->d_lock and it's seen only
on dentries with DCACHE_PAR_LOOKUP in ->d_flags.
__d_lookup_unhash() no longer needs to re-init ->d_lru. That was
previously shared (in a union) with ->d_wait but ->d_wait is now gone
so it no longer corrupts ->d_lru.
Co-developed-by: Al Viro <viro@zeniv.linux.org.uk> # saner handling of flags
Signed-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The CIFS mount path already runs through fs_context: smb3_get_tree()
calls smb3_get_tree_common() with a struct fs_context * in hand. But
the fc is dropped on the way to sget(). Plumb it through to sget_fc()
so the legacy sget() interface can go.
cifs_smb3_do_mount() now takes (struct fs_context *, struct
smb3_fs_context *). The old (fs_type, flags) pair is reconstructed
from fc->fs_type and fc->sb_flags. The flags argument was always
passed as 0 by the sole caller anyway. The cifs_dbg diagnostic now
prints fc->sb_flags directly.
cifs_match_super() and cifs_set_super() were the two void-data
callbacks for sget(). The match callback now takes
(struct super_block *, struct fs_context *) and reads struct
cifs_mnt_data out of fc->sget_key. The set callback is gone entirely:
sget_fc() pre-populates sb->s_fs_info from fc->s_fs_info before
invoking set() so set_anon_super_fc() (which just allocates an anon
bdev) is sufficient.
Before sget_fc() we stash cifs_sb in fc->s_fs_info, the per-mount data
in fc->sget_key and force fc->sb_flags to SB_NODIRATIME | SB_NOATIME
to reproduce the previous hard-coded behaviour (alloc_super() reads
fc->sb_flags). The original sb_flags is saved and restored around the
call so the rest of the mount path sees the same fc semantics as
before.
mnt_data.flags keeps its historical value of 0 so the CIFS_MS_MASK
comparison in compare_mount_options() returns the same (always-equal)
result.
No functional change. With this in place sget() has no remaining CIFS
caller.
Link: https://patch.msgid.link/20260529-work-sget-v2-3-57bbe08604e4@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
A deferred byte-range lock (an SMB2_LOCK that blocks) registers an async work on
conn->async_requests via setup_async_work(), with cancel_fn =
smb2_remove_blocked_lock and cancel_argv[0] pointing at the struct file_lock.
When the request is cancelled, the worker frees the file_lock with
locks_free_lock() and takes the cancelled early-exit, which "goto out"s and never
reaches release_async_work() -- the only site that unlinks the work from
conn->async_requests and clears cancel_fn/cancel_argv. The work therefore stays
matchable on async_requests with a live cancel_fn pointing at the freed file_lock,
until connection teardown finally runs release_async_work().
smb2_cancel() fires cancel_fn unconditionally with no state guard, so a second
SMB2_CANCEL for the same AsyncId, arriving in that window, re-runs
smb2_remove_blocked_lock() on the freed file_lock -- a slab use-after-free:
BUG: KASAN: slab-use-after-free in __locks_delete_block
__locks_delete_block
locks_delete_block
ksmbd_vfs_posix_lock_unblock
smb2_remove_blocked_lock
smb2_cancel <- 2nd SMB2_CANCEL fires cancel_fn
handle_ksmbd_work
Allocated by ...: locks_alloc_lock <- smb2_lock
Freed by ...: locks_free_lock <- smb2_lock (cancelled branch)
... cache file_lock_cache of size 192
Reproduced on mainline with KASAN by an authenticated SMB client.
Skip a work whose state is already KSMBD_WORK_CANCELLED so its cancel callback
cannot be fired a second time.
Cc: stable@vger.kernel.org
Signed-off-by: Gil Portnoy <dddhkts1@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Two concurrent same-user DHnC reconnects can both observe fp->conn == NULL
before either sets it. ksmbd_reopen_durable_fd() checks fp->conn to guard
against a handle already being reconnected, but the check and the binding
assignment are not atomic: both threads pass the guard, both call
ksmbd_conn_get() on the same fp, and both eventually reach
kfree(fp->owner.name) -- a double-free of the owner.name slab object.
The double-bound ksmbd_file also causes a write-UAF on the 344-byte
ksmbd_file_cache object when a concurrent smb2_close() spins on fp->f_lock
after the object has been freed by the losing reconnect path.
KASAN on 7.1-rc5 (48-thread concurrent reconnect, 3000 cycles):
BUG: KASAN: double-free in ksmbd_reopen_durable_fd+0x268/0x308
BUG: KASAN: slab-use-after-free in _raw_spin_lock+0xac/0x150
Write of size 4 at offset 24 into freed ksmbd_file_cache object
Five double-bind windows observed; 63 total KASAN reports triggered.
Fix: validate and claim fp->conn under write_lock(&global_ft.lock) so the
check-and-claim is atomic. ksmbd_lookup_durable_fd() already treats
fp->conn != NULL as "in use" and skips such an fp; setting fp->conn before
dropping the lock closes the race. ksmbd_conn_get() is a non-sleeping
refcount increment, safe under the rwlock. The rollback path on __open_id()
failure also clears fp->conn/tcon under the lock so concurrent readers see
a consistent state.
Fixes: b1f1e80620 ("ksmbd: centralize ksmbd_conn final release to plug transport leak")
Assisted-by: Henry (Claude):claude-opus-4
Signed-off-by: Gil Portnoy <dddhkts1@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
smb2_oplock_break_noti() and smb2_lease_break_noti() read opinfo->conn
into a local with neither READ_ONCE() nor a NULL check. Both run from
oplock_break() after opinfo_get_list() has dropped ci->m_lock, so a
concurrent SMB2 LOGOFF (session_fd_check()) can set op->conn = NULL
under ci->m_lock within that window. ksmbd_conn_r_count_inc(conn) then
writes through NULL at offset 0xc4 -- a remotely triggerable oops.
Guard both reads the way compare_guid_key() already does: read
opinfo->conn with READ_ONCE() and return early if it is NULL, before
allocating the work struct so nothing leaks. A NULL conn means the
client is gone and the break is moot, so return 0; oplock_break() treats
that as success and runs the normal teardown.
Fixes: c8efcc7861 ("ksmbd: add support for durable handles v1/v2")
Assisted-by: Henry (Claude):claude-opus-4
Signed-off-by: Gil Portnoy <dddhkts1@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Pull smb client fixes from Steve French:
- fix uninitialized variable in smb2_writev_callback()
- detect short folioq copy in cifs_copy_folioq_to_iter()
* tag 'v7.1-rc6-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
smb: client: fix uninitialized variable in smb2_writev_callback
smb: client: detect short folioq copy in cifs_copy_folioq_to_iter()
The only user of LAST_XXX outside of fs/namei.c is fs/smb/server/vfs.c;
ksmbd_vfs_path_lookup() calls vfs_path_parent_lookup() and expects a
LAST_NORM last type (or it will be ENOENT). ksmbd_vfs_rename() also calls
vfs_path_parent_lookup() but forgets the LAST_NORM check.
It does not really make sense to have vfs_path_parent_lookup() expose
the last_type because it is only needed to ensure it is LAST_NORM. So
let's do this check in vfs_path_parent_lookup() instead and keep the
LAST_XXX internal to fs/namei.c. This changes the ENOENT errno in
ksmbd_vfs_path_lookup() to EINVAL, which matches better with how this is
handled by callers of filename_parentat().
Signed-off-by: Jori Koolstra <jkoolstra@xs4all.nl>
Link: https://patch.msgid.link/20260528175854.57626-1-jkoolstra@xs4all.nl
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: NeilBrown <neil@brown.name>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
cifs_copy_folioq_to_iter() copies a requested number of bytes from
a folio queue into the destination iterator. Since the encrypted
SMB2 READ path was changed to pass the server-declared payload
length (data_len) instead of the larger folioq buffer length, the
caller can ask for fewer bytes than the folio queue holds.
In that case the helper continues walking the remaining folios after
data_size has reached zero and calls copy_folio_to_iter() with
len = 0, which is unnecessary work.
The helper also returns 0 (success) when the folio queue is
exhausted before data_size bytes have been copied. The caller has
no way to distinguish that from a full copy and the reported
transfer count ends up larger than the amount of data placed in the
iterator.
Add an early exit when data_size reaches zero, and return an error
when the folio queue is exhausted before all requested bytes have
been copied.
Signed-off-by: Jeremy Erazo <mendozayt13@gmail.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
FSCTL_SET_SPARSE in fsctl_set_sparse() modifies the file's sparse
attribute and saves it through xattr without any permission checks.
This exposes two issues:
1) A client on a read-only share can change the sparse attribute
on files it opened, even though the share is read-only.
Other FSCTL write operations already check
test_tree_conn_flag(work->tcon, KSMBD_TREE_CONN_FLAG_WRITABLE),
but FSCTL_SET_SPARSE does not.
2) Even on writable shares, clients without FILE_WRITE_DATA or
FILE_WRITE_ATTRIBUTES access should not modify the sparse
attribute. Similar handle-level checks exist in other functions
but are missing here.
Add both share-level writable check and per-handle access check.
Use goto out on error to avoid leaking file references.
Fixes: e2f34481b2 ("cifsd: add server-side procedures for SMB3")
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steve French <smfrench@gmail.com>
Signed-off-by: Sean Shen <grayhat@foxmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
ksmbd_query_inode_status() and ksmbd_lookup_fd_inode() both take a
reference on a ksmbd_inode via __ksmbd_inode_lookup() (which performs
atomic_inc_not_zero()) and later release it using a bare
atomic_dec(&ci->m_count). Unlike ksmbd_inode_put(), a bare
atomic_dec() does not check whether the reference count has reached
zero, so if the caller happens to drop the last reference, the
ksmbd_inode is leaked: it stays in the global inode hash table with
m_count == 0, future __ksmbd_inode_lookup() calls reject it via
atomic_inc_not_zero(), and ksmbd_inode_free() is never invoked.
The race is:
T1: __ksmbd_inode_lookup() -> atomic_inc_not_zero(): m_count = 2
T2: ksmbd_inode_put() -> atomic_dec_and_test(): m_count = 1
(not freed)
T1: atomic_dec(&ci->m_count) -> m_count = 0
return (LEAK)
In ksmbd_lookup_fd_inode() the matched-fp path (which now also uses
ksmbd_inode_put()) cannot currently reach m_count == 0 because the
matched ksmbd_file holds its own reference on ci, but converting it to
the proper API keeps the three call sites consistent and avoids
future regressions if the locking changes.
Because ksmbd_inode_put() may free the ksmbd_inode if this drops the
last reference, the call must happen after up_read(&ci->m_lock) on the
two affected paths in ksmbd_lookup_fd_inode(). On the no-match path
this is a pure reordering; on the matched path ksmbd_fp_get() is
moved above the unlock so that the returned ksmbd_file is pinned
before the inode reference is released.
Signed-off-by: Aleksandr Golovnya <cofedish@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Commit d07b26f392 ("ksmbd: require minimum ACE size in
smb_check_perm_dacl()") introduced a transposed bounds check:
if (offsetof(struct smb_ace, sid) + aces_size < CIFS_SID_BASE_SIZE)
Since offsetof(..sid) is 8 and CIFS_SID_BASE_SIZE is 8, this evaluates
to `aces_size < 0`. Because `aces_size` is always non-negative, this
check becomes dead code and never breaks the loop.
Worse, that commit removed the old 4-byte guard, meaning the loop now
reads `ace->size` (offset 2) even when `aces_size` is 0-3 bytes. This
re-opens a 2-byte heap out-of-bounds (OOB) read past the pntsd allocation
during subsequent SMB2_CREATE operations.
Fix this by properly transposing the comparison to require at least
16 bytes (8-byte offset + 8-byte SID base), matching the correct form
used in smb_inherit_dacl().
Fixes: d07b26f392 ("ksmbd: require minimum ACE size in smb_check_perm_dacl()")
Cc: stable@vger.kernel.org
Signed-off-by: Ali Ganiyev <ali.qaniyev@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Pull smb server fixes from Steve French:
- fix for creating tmpfiles
- fix durable reconnect error path
- validate SID in security descriptor when inheriting DACL
* tag 'v7.1-rc5-ksmbd-server-fixes' of git://git.samba.org/ksmbd:
smb/server: promote S_DEL_ON_CLS to S_DEL_PENDING when close
ksmbd: validate SID in parent security descriptor during ACL inheritance
ksmbd: fix durable reconnect error path file lifetime
Pull smb client fixes from Steve French:
- Fix missing lock
- Fix dentry in use after unmounting
- cifs.upcall security fix
- require CAP_NET_ADMIN for swn netlink
- change allocation in DUP_CTX_STR to GFP_KERNEL
- minor smbdirect debug fix
- handle_read_data() folio fix
* tag 'v7.1-rc5-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
smb: client: change allocation requirements in DUP_CTX_STR macro
smb: client: require net admin for CIFS SWN netlink
smb: smbdirect: divide, not multiply, milliseconds by 1000
cifs: Fix busy dentry used after unmounting
smb: client: use data_len for SMB2 READ encrypted folioq copy
smb: client: reject userspace cifs.spnego descriptions
smb: client: protect tc_count increment in smb2_find_smb_sess_tcon_unlocked()
Introduce smb_validate_ntsd_sid() helper to safely validate Owner SID
and Group SID inside the NT Security Descriptor (smb_ntsd) retrieved
from the parent directory.
Cc: stable@vger.kernel.org
Signed-off-by: Junyi Liu <moss80199@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
After a durable reconnect succeeds, ksmbd_reopen_durable_fd() republishes
the same ksmbd_file into the session volatile-id table. If smb2_open()
then takes a later error path, cleanup first calls ksmbd_fd_put(work, fp)
and then unconditionally calls ksmbd_put_durable_fd(dh_info.fp).
In this case fp and dh_info.fp are the same object. The first put drops the
reconnect lookup reference, but the final durable put can run
__ksmbd_close_fd(NULL, fp). Because the final close is not session-aware,
it can free the file object without removing the volatile-id entry that was
just published into the session table.
Use the session-aware put for the final reconnect drop when the reconnect
had already succeeded and the error path is cleaning up the republished
file. Earlier reconnect failures, before fp is assigned to dh_info.fp, keep
using the durable-only put path.
Fixes: 1baff47b81 ("ksmbd: fix use-after-free in smb2_open during durable reconnect")
Signed-off-by: Junyi Liu <moss80199@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Currently, the macro DUP_CTX_STR allocates new_ctx->field using
GFP_ATOMIC. DUP_CTX_STR is only used in smb3_fs_context_dup(), which
is never called in an atomic context. Using GFP_ATOMIC puts unnecessary
pressure on emergency memory pools.
Change GFP_ATOMIC to GFP_KERNEL.
Signed-off-by: Fredric Cover <fredric.cover.lkernel@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CIFS_GENL_CMD_SWN_NOTIFY is the userspace witness-notify command. The
intended sender is the cifs.witness helper, but the generic-netlink
operation currently has no capability flag, so any local process can send
RESOURCE_CHANGE or CLIENT_MOVE notifications to the in-kernel witness
handler.
The same family exposes CIFS_GENL_MCGRP_SWN without multicast-group
capability flags. Register messages sent to that group include the witness
registration id and, for NTLM-authenticated mounts, the username, domain,
and password attributes copied from the CIFS session. An unprivileged
local process should not be able to join that group and receive those
messages.
Require CAP_NET_ADMIN for incoming SWN_NOTIFY commands with
GENL_ADMIN_PERM, and require CAP_NET_ADMIN over the network namespace for
joining the SWN multicast group with GENL_MCAST_CAP_NET_ADMIN. The
cifs.witness service runs with the privileges needed for both operations.
Fixes: fed979a7e0 ("cifs: Set witness notification handler for messages from userspace daemon")
Cc: stable@vger.kernel.org
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Steve French <stfrench@microsoft.com>
Unless smbdirect_connection_legacy_debug_proc_show()
wants to debug-log keep_alive_interval as microseconds,
a magnitude higher precision than available by the way,
keepalive_interval_msec should not be multiplied by 1000.
Fixes: cc55f65dd3 ("smb: client: make use of common smbdirect_socket_parameters")
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
Since commit 340cea84f6 ("cifs: open files should not hold ref on
superblock"), cifs file only holds the dentry ref_cnt, the cifs file
close work(cfile->deferred) could be executed after unmounting, which
will trigger a warning in generic_shutdown_super:
BUG: Dentry 00000000a14a6845{i=c,n=file} still in use (1) [unmount of
cifs cifs]
The detailed processs is:
process A process B kworker
fd = open(PATH)
vfs_open
file->__f_path = *path // dentry->d_lockref.count = 1
cifs_open
cifs_new_fileinfo
cfile->dentry = dget(dentry) // dentry->d_lockref.count = 2
close(fd)
__fput
cifs_close
queue_delayed_work(deferredclose_wq, cfile->deferred)
dput(dentry) // dentry->d_lockref.count = 1
smb2_deferred_work_close
_cifsFileInfo_put
list_del(&cifs_file->flist)
umount
cleanup_mnt
deactivate_super
cifs_kill_sb
cifs_close_all_deferred_files_sb
cifs_close_all_deferred_files
// cannot find cfile, skip _cifsFileInfo_put
kill_anon_super
generic_shutdown_super
shrink_dcache_for_umount
umount_check
WARN ! // dentry->d_lockref.count = 1
cifsFileInfo_put_final
dput(cifs_file->dentry)
// dentry->d_lockref.count = 0
Fix it by flushing 'deferredclose_wq' before calling kill_anon_super.
Fetch a reproducer in https://bugzilla.kernel.org/show_bug.cgi?id=221548.
Fixes: 340cea84f6 ("cifs: open files should not hold ref on superblock")
Cc: stable@vger.kernel.org
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This flag indicates the path should be opened if it's a regular file.
This is useful to write secure programs that want to avoid being
tricked into opening device nodes with special semantics while thinking
they operate on regular files. This is a requested feature from the
uapi-group[1].
The previously introduced EFTYPE error code is returned when the path
doesn't refer to a regular file. For example, if openat2 is called on
path /dev/null with OPENAT2_REGULAR in the flag param, it will return
-EFTYPE.
When used in combination with O_CREAT, either the regular file is
created, or if the path already exists, it is opened if it's a regular
file. Otherwise, -EFTYPE is returned.
When OPENAT2_REGULAR is combined with O_DIRECTORY, -EINVAL is returned
as it doesn't make sense to open a path that is both a directory and a
regular file.
The UAPI bit lives in the upper 32 bits of open_how::flags
(((__u64)1 << 32)) so that open(2) and openat(2) -- whose @flags
argument is a C int -- cannot physically express it. This is a
structural guarantee, not a runtime mask: the bit is unrepresentable in
32 bits.
Because the rest of the VFS open path narrows to 32 bits in several
places (op->open_flag, f->f_flags, the unsigned open_flag argument of
i_op->atomic_open()), build_open_flags() translates OPENAT2_REGULAR
into a kernel-internal lower-32-bit carrier __O_REGULAR (bit 4, unused
as an O_* on every architecture) before the assignment to op->open_flag.
__O_REGULAR then rides through the existing channels exactly like
__FMODE_EXEC. do_dentry_open() strips it so it cannot leak back to
userspace via fcntl(F_GETFL).
Four BUILD_BUG_ON_MSG() invariants in build_open_flags() prevent any
future bit collision or accidental low-32 redefinition:
- VALID_OPEN_FLAGS fits in 32 bits.
- OPENAT2_REGULAR lives in the upper 32 bits.
- OPENAT2_REGULAR does not alias any open()/openat() flag.
- __O_REGULAR does not alias any user-visible flag.
[1]: https://uapi-group.org/kernel-features/#ability-to-only-open-regular-files
Christian Brauner <brauner@kernel.org> says:
Move OPENAT2_REGULAR to the upper 32 bits of open_how::flags with a
kernel-internal __O_REGULAR carrier so that open(2)/openat(2) cannot
encode the flag; add BUILD_BUG_ON_MSG() invariants and register
__O_REGULAR in the fcntl_init() allocation-uniqueness BUILD_BUG_ON()
(bit count 21 -> 22).
Signed-off-by: Dorjoy Chowdhury <dorjoychy111@gmail.com>
Link: https://patch.msgid.link/20260328172314.45807-2-dorjoychy111@gmail.com
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Aleksa Sarai <aleksa@amutable.com>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Pull smb server fixes from Steve French:
- Fix two null pointer dereferences and a memory leak
* tag 'v7.1-rc4-ksmbd-server-fixes' of git://git.samba.org/ksmbd:
ksmbd: fix null pointer dereference in compare_guid_key()
ksmbd: fix null pointer dereference in proc_show_files()
ksmbd: fix SID memory leak in set_posix_acl_entries_dacl() on overflow
In handle_read_data() the encrypted/folioq branch
(buf_len <= data_offset, reached via receive_encrypted_read for
transform PDUs > CIFSMaxBufSize + MAX_HEADER_SIZE) copies the READ
payload using buffer_len rather than data_len:
rdata->result = cifs_copy_folioq_to_iter(buffer, buffer_len,
cur_off,
&rdata->subreq.io_iter);
...
rdata->got_bytes = buffer_len;
buffer_len comes from the SMB3 transform header OriginalMessageSize
field (OriginalMessageSize - read_rsp_size); it represents the size
of the decrypted message after the SMB2 header. data_len comes from
the SMB2 READ response DataLength field; it represents the actual
READ payload size and may be smaller than buffer_len when the
decrypted message contains padding or other trailing bytes after the
READ payload. The existing check `data_len > buffer_len - pad_len`
only enforces an upper bound, so a server that emits
OriginalMessageSize larger than read_rsp_size + pad_len + data_len
passes the check and the kernel copies buffer_len bytes per response,
ignoring the server-asserted DataLength.
Two observable failures with a crafted server (DataLength=4,
buffer_len=20000):
- the kernel returns 20000 bytes per sub-request to userspace and
sets got_bytes = buffer_len, even though the response claimed
only 4 bytes of payload;
- on a partial netfs sub-request whose iterator is sized to
data_len, the over-large copy_folio_to_iter() short-reads,
cifs_copy_folioq_to_iter() returns -EIO via the n != len path,
and the entire netfs read collapses to -EIO even though the
leading sub-requests succeeded.
Use data_len for the copy length and for got_bytes so the kernel
honours the server-asserted READ payload size. For well-formed
servers (where buffer_len == pad_len + data_len) the change is
behaviour-equivalent.
Cc: stable@vger.kernel.org
Signed-off-by: Jeremy Erazo <mendozayt13@gmail.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
cifs.spnego key descriptions contain authority-bearing fields such as
pid, uid, creduid, and upcall_target that cifs.upcall treats as
kernel-originating inputs. However, userspace can also create keys of
this type through request_key(2) or add_key(2), allowing those fields to
be supplied without CIFS origin.
Only accept cifs.spnego descriptions while CIFS is using its private
spnego_cred to request the key.
Fixes: f1d662a7d5 ("[CIFS] Add upcall files for cifs to use spnego/kerberos")
Assisted-by: avom-custom-harness:gpt-5.5-qwen3.6-mod-mix
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Asim Viladi Oglu Manizada <manizada@pm.me>
Signed-off-by: Steve French <stfrench@microsoft.com>
Commit 96c4af4185 ("cifs: Fix locking usage for tcon fields")
refactored cifs code to change cifs_tcp_ses_lock for tc_lock around
tc_count changes.
There was missing lock around tc_count increment inside
smb2_find_smb_sess_tcon_unlocked().
Cc: stable@vger.kernel.org
Fixes: 96c4af4185 ("cifs: Fix locking usage for tcon fields")
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Henrique Carvalho <henrique.carvalho@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Pull vfs fixes from Christian Brauner:
"This contains a fixes for the current development cycle. Note that AI
related review sometimes delays fixes a bit because we find more fixes
for the fixes. I might try and send smaller but more fixes PRs if this
trend keeps up.
- Fix various netfslib bugs
- Fix an out-of-bounds write when listing idmappings
- Fix the return values in jfs_mkdir() and orangefs_mkdir()
- Fix a writeback writeback array overflow in fuse
- Fix a forced iversion increment on lazytime timestamp updates
- Reject a negative timeval component in kern_select()
- Fix error return when vfs_mkdir() fails in the cachefiles code
- Fix wrong error code returned for pidns ioctls"
* tag 'vfs-7.1-rc5.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (31 commits)
cachefiles: Fix error return when vfs_mkdir() fails
afs: Fix the locking used by afs_get_link()
netfs, afs: Fix write skipping in dir/link writepages
netfs: Fix netfs_read_folio() to wait on writeback
netfs: Fix folio->private handling in netfs_perform_write()
netfs: Fix partial invalidation of streaming-write folio
netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()
netfs: Fix leak of request in netfs_write_begin() error handling
netfs: Fix early put of sink folio in netfs_read_gaps()
netfs: Fix write streaming disablement if fd open O_RDWR
netfs: Fix read-gaps to remove netfs_folio from filled folio
netfs: Fix potential deadlock in write-through mode
netfs: Fix streaming write being overwritten
netfs: Defer the emission of trace_netfs_folio()
netfs: Fix netfs_invalidate_folio() to clear dirty bit if all changes gone
netfs: Fix overrun check in netfs_extract_user_iter()
netfs: fix error handling in netfs_extract_user_iter()
netfs: Fix potential uninitialised var in netfs_extract_user_iter()
netfs: fix VM_BUG_ON_FOLIO() issue in netfs_write_begin() call
netfs: Fix zeropoint update where i_size > remote_i_size
...
SMB2 READ response validation in cifs_readv_receive() and
handle_read_data() checks data_offset + data_len against the received
buffer length. Both values are attacker-controlled fields from the
server response and are stored as unsigned int, so the addition can
wrap before the bounds check:
fs/smb/client/transport.c:1259
if (!use_rdma_mr && (data_offset + data_len > buflen))
fs/smb/client/smb2ops.c:4839
else if (buf_len >= data_offset + data_len)
A malicious SMB server can use this to bypass validation. In the
non-encrypted receive path the client attempts an oversized socket
read and stalls for the SMB response timeout (180 seconds) before
reconnecting. In the SMB3 encrypted path, runtime testing shows the
malformed length can reach copy_to_iter() in handle_read_data() with
attacker-controlled size, where usercopy hardening stops the oversized
copy before bytes reach userspace.
Guard both call sites with check_add_overflow(), which is already
used elsewhere in this subsystem (smb2pdu.c). On overflow, treat the
response as malformed and reject with -EIO.
Signed-off-by: Jeremy Erazo <mendozayt13@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
On 32-bit architectures, the infinite loop is as follows:
len = p->ErrorDataLength == 0xfffffff8
u8 *next = p->ErrorContextData + len
next == p
On 32-bit architectures, the out-of-bounds read is as follows:
len = p->ErrorDataLength == 0xfffffff0
u8 *next = p->ErrorContextData + len
next == (u8 *)p - 8
Reported-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Fixes: 76894f3e2f ("cifs: improve symlink handling for smb2+")
Cc: stable@vger.kernel.org
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Signed-off-by: Steve French <stfrench@microsoft.com>
session_fd_check() walks the per-inode m_op_list during durable-handle
session teardown and sets op->conn = NULL for every opinfo whose conn
matched the closing session's connection. The matching opinfo, however,
stays linked in its per-ClientGuid lease_table_list entry's lb->lease_list
because destroy_lease_table() only runs on full TCP-connection teardown,
not on SESSION_LOGOFF.
If the same TCP connection then negotiates a fresh session with the
same ClientGuid (ClientGuid is bound to NEGOTIATE, not the session, and
is unchanged across LOGOFF + SETUP) and issues a SMB2 CREATE with a
lease context on a different inode, find_same_lease_key() walks
lb->lease_list, reaches the stale opinfo, and calls compare_guid_key(),
which unconditionally dereferences opinfo->conn->ClientGUID. The conn
pointer is NULL and the kernel panics.
Reproducer requires only a successful SMB2 SESSION_SETUP and a share
configured with 'durable handles = yes'. KASAN report on mainline
70390501d1:
general protection fault, probably for non-canonical address
0xdffffc0000000069: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000348-0x000000000000034f]
Workqueue: ksmbd-io handle_ksmbd_work
RIP: 0010:bcmp+0x5b/0x230
Call Trace:
compare_guid_key+0x4b/0xd0
find_same_lease_key+0x324/0x690
smb2_open+0x6aea/0x8e60
handle_ksmbd_work+0x796/0xee0
...
Faulting address 0x348 is the offset of ClientGUID within struct
ksmbd_conn, confirming opinfo->conn was NULL.
Read opinfo->conn once and bail out if it has been cleared by a
concurrent session_fd_check(). A half-detached opinfo cannot be the
owner of an active lease, so returning 0 is the correct match result.
Fixes: c8efcc7861 ("ksmbd: add support for durable handles v1/v2")
Cc: stable@vger.kernel.org
Signed-off-by: Jeremy Laratro <research@aradex.io>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
When a SMB2 client opens a file with a durable v2 handle and then issues
SMB2 SESSION_LOGOFF, session_fd_check() clears fp->tcon = NULL on the
reconnectable file pointer but leaves the fp registered in global_ft.idr
until the durable scavenger fires (up to fp->durable_timeout seconds
later).
During that window any read of /proc/fs/ksmbd/files (mode 0400) panics
the kernel because proc_show_files() walks global_ft.idr and
unconditionally dereferences fp->tcon->id with no NULL guard.
Reproducer requires only a successful SMB2 SESSION_SETUP and a share
configured with 'durable handles = yes'. KASAN report on mainline
70390501d1:
general protection fault, probably for non-canonical address
0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
RIP: 0010:proc_show_files+0x118/0x740
Call Trace:
proc_show_files+0x118/0x740
seq_read_iter+0x4ef/0xe10
proc_reg_read_iter+0x1b7/0x280
...
Guard the dereference. A durable-disconnected fp legitimately has no
tcon; report its tree id as 0 rather than oopsing.
Fixes: b38f99c121 ("ksmbd: add procfs interface for runtime monitoring and statistics")
Cc: stable@vger.kernel.org
Signed-off-by: Jeremy Laratro <research@aradex.io>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Commit 299f962c0b ("ksmbd: use check_add_overflow() to prevent u16
DACL size overflow") added check_add_overflow() guards that break out
of the ACE-building loops in set_posix_acl_entries_dacl() when the
accumulated DACL size would wrap past 65535.
However, each iteration allocates a struct smb_sid via kmalloc_obj()
at the top of the loop and relies on the kfree(sid) call at the end
of the loop body (the 'pass_same_sid' label in the first loop, and
the explicit kfree at the tail of the second loop) to release it.
The newly introduced 'break' statements bypass those kfree() calls,
leaking the sid buffer every time an overflow is detected.
A malicious or malformed file with enough POSIX ACL entries to trip
the overflow check will leak one or more struct smb_sid allocations
on every request that touches the file's DACL, providing a trivial
kernel memory exhaustion vector.
Free sid before breaking out of the loops to plug the leak.
Fixes: 299f962c0b ("ksmbd: use check_add_overflow() to prevent u16 DACL size overflow")
Cc: stable@vger.kernel.org
Signed-off-by: Ferry Meng <mengferry@linux.alibaba.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
New Infolevels for QUERY_DIR (and QUERY_INFO) levels 78 through 81 are
now being used by Windows clients and were added to the documentation.
Add defines for them (and correct some typos in documentation). See
MS-SMB2 2.2.33 and MS-FSCC 2.4
Signed-off-by: Steve French <stfrench@microsoft.com>
FS_ATTRIBUTE_INFORMATION responses have always reported
FILE_CASE_SENSITIVE_SEARCH and FILE_CASE_PRESERVED_NAMES
unconditionally. Case-insensitive filesystems like exFAT, and
casefolded directories on ext4 or f2fs, have no way to signal
their actual semantics to SMB clients.
Now that filesystems expose case behavior through ->fileattr_get,
query it via vfs_fileattr_get() and translate the FS_XFLAG_CASEFOLD
and FS_XFLAG_CASENONPRESERVING flags into the corresponding SMB
attributes. Filesystems without ->fileattr_get continue reporting
default POSIX behavior (case-sensitive, case-preserving).
SMB's FS_ATTRIBUTE_INFORMATION reports per-share attributes from
the share root, not per-file. Shares mixing casefold and
non-casefold directories report the root directory's behavior.
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Reviewed-by: Roland Mainz <roland.mainz@nrubsig.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260507-case-sensitivity-v14-15-e62cc8200435@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Upper layers such as NFSD need a way to query whether a filesystem
handles filenames in a case-sensitive manner. Report CIFS/SMB case
handling behavior via FS_XFLAG_CASEFOLD and
FS_XFLAG_CASENONPRESERVING.
The authoritative source is the server itself: at mount time CIFS
issues QueryFSInfo(FS_ATTRIBUTE_INFORMATION) and caches the reply
on the tcon. That reply carries FILE_CASE_SENSITIVE_SEARCH and
FILE_CASE_PRESERVED_NAMES, which reflect whatever case handling
the share actually implements after SMB3.1.1 POSIX extensions
negotiation. Translating those two bits into the VFS flags lets
cifs_fileattr_get report what the server advertises rather than
what the client was asked to pretend.
QueryFSInfo is best-effort; the mount completes even if the server
does not answer. MaxPathNameComponentLength is zero in that case
and is used as the "no reply received" sentinel. When no reply is
available, fall back to the nocase mount option so that the reported
behavior agrees with the dentry comparison operations installed on
the superblock.
The callback is registered on cifs_dir_inode_ops so that NFSD,
ksmbd, and other consumers querying case handling against a
directory get a definitive answer, and on cifs_file_inode_ops to
preserve FS_COMPR_FL reporting on regular files. cifs_set_ops()
also installs cifs_namespace_inode_operations on DFS referral
directories that carry IS_AUTOMOUNT; register the same callback
there so the answer does not depend on whether the directory is
a referral point.
Registering fileattr_get routes FS_IOC_GETFLAGS through
vfs_fileattr_get() and short-circuits the syscall's fallback to
cifs_ioctl(). That fallback invoked CIFSGetExtAttr() under
CONFIG_CIFS_POSIX and CONFIG_CIFS_ALLOW_INSECURE_LEGACY on servers
advertising CIFS_UNIX_EXTATTR_CAP, surfacing the SMB1 Unix-extension
immutable, append, and nodump bits. cifs_fileattr_get carries over
only FS_COMPR_FL from cached cifsAttrs; the SMB1 extattr fetch is
not reproduced. SMB1 is deprecated, and acquiring a netfid from
within a dentry-only callback is not worth preserving a path tied
to an insecure legacy dialect.
Acked-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Roland Mainz <roland.mainz@nrubsig.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260507-case-sensitivity-v14-9-e62cc8200435@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Pull smb client fixes from Steve French:
- Fix for two ACL issues (security fix to validate dacloffset better
and chmod fix)
- Fix out of bounds reads (in check_wsl_eas and smb2_check_msg for
symlinks)
- Two Kerberos fixes including an important one when AES-256 encryption
chosen
- Fix open_cached_dir problem when directory leases disabled
* tag 'v7.1-rc3-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
smb: client: validate dacloffset before building DACL pointers
smb/client: fix out-of-bounds read in smb2_compound_op()
smb/client: fix out-of-bounds read in symlink_data()
smb: client: Zero-pad short GSS session keys per MS-SMB2
smb: client: Use FullSessionKey for AES-256 encryption key derivation
smb: client: use kzalloc to zero-initialize security descriptor buffer
cifs: abort open_cached_dir if we don't request leases
parse_sec_desc(), build_sec_desc(), and the chown path in
id_mode_to_cifs_acl() all add the server-supplied dacloffset to pntsd
before proving a DACL header fits inside the returned security
descriptor.
On 32-bit builds a malicious server can return dacloffset near
U32_MAX, wrap the derived DACL pointer below end_of_acl, and then slip
past the later pointer-based bounds checks. build_sec_desc() and
id_mode_to_cifs_acl() can then dereference DACL fields from the wrapped
pointer in the chmod/chown rewrite paths.
Validate dacloffset numerically before building any DACL pointer and
reuse the same helper at the three DACL entry points.
Fixes: bc3e9dd9d1 ("cifs: Change SIDs in ACEs while transferring file ownership.")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
If a server sends a truncated response but a large OutputBufferLength, and
terminates the EA list early, check_wsl_eas() returns success without
validating that the entire OutputBufferLength fits within iov_len.
Then smb2_compound_op() does:
memcpy(idata->wsl.eas, data[0], size[0]);
Where size[0] is OutputBufferLength. If iov_len is smaller than size[0],
memcpy can read beyond the end of the rsp_iov allocation and leak adjacent
kernel heap memory.
Link: https://lore.kernel.org/linux-cifs/d998240c-aca9-420d-9dbd-f5ba24af19e0@chenxiaosong.com/
Fixes: ea41367b2a ("smb: client: introduce SMB2_OP_QUERY_WSL_EA")
Cc: stable@vger.kernel.org
Signed-off-by: Zisen Ye <zisenye@stu.xidian.edu.cn>
Reviewed-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Signed-off-by: Steve French <stfrench@microsoft.com>
Per MS-SMB2 section 3.2.5.3, Session.SessionKey is the first 16 bytes
of the GSS cryptographic key, right-padded with zero bytes if the key
is shorter than 16 bytes.
SMB2_auth_kerberos() copies the GSS session key from the cifs.upcall
response using kmemdup(msg->data, msg->sesskey_len, ...) and stores
the GSS-reported length verbatim in ses->auth_key.len. generate_key()
reads SMB2_NTLMV2_SESSKEY_SIZE bytes from this buffer when feeding the
HMAC-SHA256 KDF for signing key derivation. If a GSS mechanism returns
a session key shorter than 16 bytes (e.g. a deprecated single-DES
Kerberos enctype with an 8-byte session key), the KDF call performs an
out-of-bounds slab read and derives keys that do not match the server,
which pads per the spec.
Modern KDCs disable short-key enctypes by default, so this is latent
rather than reachable in production, but it is still a kernel heap
over-read.
Allocate auth_key.response with kzalloc() at a length of
max(msg->sesskey_len, SMB2_NTLMV2_SESSKEY_SIZE), copy the GSS key in,
and rely on kzalloc()'s zero initialization for the spec-mandated
padding. Set ses->auth_key.len to the padded length. Larger GSS keys
(e.g. the 32-byte aes256-cts-hmac-sha1-96 session key) continue to be
stored at their natural length, preserving the FullSessionKey path.
Emit a cifs_dbg(VFS, ...) message when a short key is encountered to
surface deprecated-enctype usage.
NTLMv2 and NTLMSSP code paths produce a 16-byte session key by
construction and are unaffected.
Signed-off-by: Piyush Sachdeva <psachdeva@microsoft.com>
Signed-off-by: Piyush Sachdeva <s.piyush1024@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
