kernel/linux.git/fs/smb, branch v6.12.96

smb: client: reject overlapping data areas in SMB2 responses

2026-07-18T14:52:17+00:00

commit 8986c932905ea508d66da421eb2eb6e676ace1fe upstream. Commit 53b7c271f06b ("smb: client: restrict implied bcc[0] exemption to responses without data area") restricted the implied bcc[0] length exception to responses without a data area. However, the overlap handling in __smb2_calc_size() clears data_length, which can make an invalid response appear to have no data area and so qualify for the exception. Track data area overlap separately and reject such responses before applying the length compatibility exceptions. Fixes: 53b7c271f06b ("smb: client: restrict implied bcc[0] exemption to responses without data area") Cc: stable@vger.kernel.org Signed-off-by: Shoichiro Miyamoto Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: client: mask server-provided mode to 07777 in modefromsid

2026-07-18T14:52:06+00:00

commit e3d9c7160d483fc8f9e225aafad8ecbbc43f3151 upstream. When modefromsid is active, parse_dacl() applies the server-provided sub_auth[2] value from the NFS mode SID to cf_mode without masking to 07777. Apply the correct masking, same as in the read path. Fixes: e2f8fbfb8d09c ("cifs: get mode bits from special sid on stat") Signed-off-by: Norbert Manthey Assisted-by: Kiro:claude-opus-4.6 Cc: stable@vger.kernel.org Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: client: fix atime clamp check in read completion

2026-07-18T14:52:06+00:00

commit 0b043279e73880bee21d3b1f221bafda5af1b27e upstream. cifs_rreq_done() updates the inode atime to current_time(inode) after a netfs read. It then preserves the CIFS rule that atime should not be older than mtime, because some applications break if atime is less than mtime. That rule only requires clamping when atime < mtime. The current check uses the raw non-zero result of timespec64_compare(). It therefore takes the clamp path for both atime < mtime and atime > mtime. The latter is the normal case when reading an older file: the newly recorded atime is newer than the file mtime. The completion handler then immediately moves atime back to mtime, losing the access time that was just recorded. Userspace tools that rely on atime, such as stat, find -atime, backup tools or cold-data classifiers, can therefore see a recently read CIFS file as not recently accessed. This is easy to miss because the bug is silent: read I/O still succeeds, no error is reported, and many systems either do not check atime after reads or mount with policies such as relatime/noatime. It becomes visible when a CIFS file has an mtime older than the current time, the file is read, and the local inode atime is inspected before a later revalidation replaces the cached timestamps. Clamp only when atime is actually older than mtime. This matches the same atime/mtime rule used when applying CIFS inode attributes. Fixes: 69c3c023af25 ("cifs: Implement netfslib hooks") Cc: stable@vger.kernel.org Signed-off-by: Xu Rao Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: client: harden POSIX SID length parsing

2026-07-18T14:52:06+00:00

commit 7ad2bcf2441430bb2e918fb3ef9a90d775a6e422 upstream. posix_info_sid_size() reads sid[1] to obtain the subauthority count, but its existing boundary check still accepts buffers with only one remaining byte. Require two bytes before reading sid[1] so all client paths that reuse the helper reject truncated POSIX SIDs safely. Fixes: 349e13ad30b4 ("cifs: add smb2 POSIX info level") Cc: stable@vger.kernel.org Reported-by: Yuan Tan Reported-by: Yifan Wu Reported-by: Juefei Pu Reported-by: Xin Liu Assisted-by: Codex:gpt-5.4 Signed-off-by: Zihan Xi Signed-off-by: Ren Wei Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: client: use unaligned reads in parse_posix_ctxt()

2026-07-18T14:52:05+00:00

commit b86467cd2691192ad4809a5a6e922fc24b8e9839 upstream. The server controls create-context DataOffset, so the POSIX context data pointer may be misaligned on strict-alignment architectures. Use get_unaligned_le32() when reading nlink, reparse_tag, and mode. Fixes: 69dda3059e7a ("cifs: add SMB2_open() arg to return POSIX data") Cc: stable@vger.kernel.org Signed-off-by: Zihan Xi Signed-off-by: Ren Wei Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: client: Fix next buffer leak in receive_encrypted_standard()

2026-07-18T14:52:05+00:00

commit 1c6267a1d5cf4c73b656f8181b310cbbb3e4767b upstream. receive_encrypted_standard() allocates next_buffer before checking whether the number of compound PDUs already reached MAX_COMPOUND. If the limit check fails, the function returns immediately and the newly allocated next_buffer is not assigned to server->smallbuf/server->bigbuf, making it leaked. Move the MAX_COMPOUND check before allocating next_buffer. Fixes: b24df3e30cbf ("cifs: update receive_encrypted_standard to handle compounded responses") Cc: stable@vger.kernel.org Signed-off-by: Haoxiang Li Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: client: fix double-free in SMB2_close() replay

2026-07-18T14:52:05+00:00

commit f96e1cdcb63ed3321142ff2fcdf784e32cda8fee upstream. A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_close_init() fails before the next send, cleanup retains the previous buffer type and frees that response again. Reset response bookkeeping before each attempt to prevent the stale free. Fixes: 4f1fffa23769 ("cifs: commands that are retried should have replay flag set") Cc: stable@vger.kernel.org Signed-off-by: Henrique Carvalho Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: client: fix double-free in SMB2_open() replay

2026-07-18T14:52:05+00:00

commit b55e182f2324bc6a604c21a47aa6c448f719a532 upstream. A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_open_init() fails before the next send, cleanup retains the previous buffer type and frees that response again. Reset response bookkeeping before each attempt to prevent the stale free. Fixes: 4f1fffa23769 ("cifs: commands that are retried should have replay flag set") Cc: stable@vger.kernel.org Signed-off-by: Henrique Carvalho Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: client: fix double-free in SMB2_flush() replay

2026-07-18T14:52:05+00:00

commit 4be31c943a3a27a5a0251dbb8f5cb89059ec3d5a upstream. SMB2_flush() keeps its response buffer bookkeeping across replay attempts. If a replayable flush response is received and the retry then fails before cifs_send_recv() stores a replacement response, flush_exit will free the stale response pointer a second time. Reinitialize resp_buftype and rsp_iov at the top of the replay loop so cleanup only acts on response state produced by the current attempt. This fixes a double-free without changing replay handling for successful requests. Fixes: 4f1fffa23769 ("cifs: commands that are retried should have replay flag set") Cc: stable@vger.kernel.org Reported-by: Yuan Tan Reported-by: Zhengchuan Liang Reported-by: Xin Liu Assisted-by: Codex:GPT-5.4 Acked-by: Henrique Carvalho Signed-off-by: Zhao Zhang Signed-off-by: Ren Wei Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: client: fix change notify replay double-free

2026-07-18T14:52:05+00:00

commit 145f820dcbb2cced374f2532f8a61a44dce4a615 upstream. A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_notify_init() fails before the next send, cleanup retains the previous buffer type and frees that response again. Reset response bookkeeping before each attempt to prevent the stale free. Fixes: 4f1fffa23769 ("cifs: commands that are retried should have replay flag set") Cc: stable@vger.kernel.org Signed-off-by: Henrique Carvalho Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman