kernel/linux.git/fs/smb/client, branch v6.6.132

smb: client: fix krb5 mount with username option

2026-03-25T10:06:02+00:00

commit 12b4c5d98cd7ca46d5035a57bcd995df614c14e1 upstream. Customer reported that some of their krb5 mounts were failing against a single server as the client was trying to mount the shares with wrong credentials. It turned out the client was reusing SMB session from first mount to try mounting the other shares, even though a different username= option had been specified to the other mounts. By using username mount option along with sec=krb5 to search for principals from keytab is supported by cifs.upcall(8) since cifs-utils-4.8. So fix this by matching username mount option in match_session() even with Kerberos. For example, the second mount below should fail with -ENOKEY as there is no 'foobar' principal in keytab (/etc/krb5.keytab). The client ends up reusing SMB session from first mount to perform the second one, which is wrong. ``` $ ktutil ktutil: add_entry -password -p testuser -k 1 -e aes256-cts Password for testuser@ZELDA.TEST: ktutil: write_kt /etc/krb5.keytab ktutil: quit $ klist -ke Keytab name: FILE:/etc/krb5.keytab KVNO Principal ---- ---------------------------------------------------------------- 1 testuser@ZELDA.TEST (aes256-cts-hmac-sha1-96) $ mount.cifs //w22-root2/scratch /mnt/1 -o sec=krb5,username=testuser $ mount.cifs //w22-root2/scratch /mnt/2 -o sec=krb5,username=foobar $ mount -t cifs | grep -Po 'username=\K\w+' testuser testuser ``` Reported-by: Oscar Santos Signed-off-by: Paulo Alcantara (Red Hat) Cc: David Howells Cc: linux-cifs@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: client: Compare MACs in constant time

2026-03-25T10:05:58+00:00

commit 26bc83b88bbbf054f0980a4a42047a8d1e210e4c upstream. To prevent timing attacks, MAC comparisons need to be constant-time. Replace the memcmp() with the correct function, crypto_memneq(). Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Acked-by: Paulo Alcantara (Red Hat) Signed-off-by: Eric Biggers Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

cifs: open files should not hold ref on superblock

2026-03-25T10:05:57+00:00

[ Upstream commit 340cea84f691c5206561bb2e0147158fe02070be ] Today whenever we deal with a file, in addition to holding a reference on the dentry, we also get a reference on the superblock. This happens in two cases: 1. when a new cinode is allocated 2. when an oplock break is being processed The reasoning for holding the superblock ref was to make sure that when umount happens, if there are users of inodes and dentries, it does not try to clean them up and wait for the last ref to superblock to be dropped by last of such users. But the side effect of doing that is that umount silently drops a ref on the superblock and we could have deferred closes and lease breaks still holding these refs. Ideally, we should ensure that all of these users of inodes and dentries are cleaned up at the time of umount, which is what this code is doing. This code change allows these code paths to use a ref on the dentry (and hence the inode). That way, umount is ensured to clean up SMB client resources when it's the last ref on the superblock (For ex: when same objects are shared). The code change also moves the call to close all the files in deferred close list to the umount code path. It also waits for oplock_break workers to be flushed before calling kill_anon_super (which eventually frees up those objects). Fixes: 24261fc23db9 ("cifs: delay super block destruction until all cifsFileInfo objects are gone") Fixes: 705c79101ccf ("smb: client: fix use-after-free in cifs_oplock_break") Cc: Signed-off-by: Shyam Prasad N Signed-off-by: Steve French [ adapted kmalloc_obj() macro to kmalloc(sizeof()) ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

smb: client: fix iface port assignment in parse_server_interfaces

2026-03-25T10:05:54+00:00

commit d4c7210d2f3ea481a6481f03040a64d9077a6172 upstream. parse_server_interfaces() initializes interface socket addresses with CIFS_PORT. When the mount uses a non-default port this overwrites the configured destination port. Later, cifs_chan_update_iface() copies this sockaddr into server->dstaddr, causing reconnect attempts to use the wrong port after server interface updates. Use the existing port from server->dstaddr instead. Cc: stable@vger.kernel.org Fixes: fe856be475f7 ("CIFS: parse and store info on iface queries") Tested-by: Dr. Thomas Orgis Reviewed-by: Enzo Matsumiya Signed-off-by: Henrique Carvalho Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: client: fix in-place encryption corruption in SMB2_write()

2026-03-25T10:05:54+00:00

commit d78840a6a38d312dc1a51a65317bb67e46f0b929 upstream. SMB2_write() places write payload in iov[1..n] as part of rq_iov. smb3_init_transform_rq() pointer-shares rq_iov, so crypt_message() encrypts iov[1] in-place, replacing the original plaintext with ciphertext. On a replayable error, the retry sends the same iov[1] which now contains ciphertext instead of the original data, resulting in corruption. The corruption is most likely to be observed when connections are unstable, as reconnects trigger write retries that re-send the already-encrypted data. This affects SFU mknod, MF symlinks, etc. On kernels before 6.10 (prior to the netfs conversion), sync writes also used this path and were similarly affected. The async write path wasn't unaffected as it uses rq_iter which gets deep-copied. Fix by moving the write payload into rq_iter via iov_iter_kvec(), so smb3_init_transform_rq() deep-copies it before encryption. Cc: stable@vger.kernel.org #6.3+ Acked-by: Henrique Carvalho Acked-by: Shyam Prasad N Acked-by: Paulo Alcantara (Red Hat) Signed-off-by: Bharath SM Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: client: fix atomic open with O_DIRECT & O_SYNC

2026-03-25T10:05:54+00:00

commit 4a7d2729dc99437dbb880a64c47828c0d191b308 upstream. When user application requests O_DIRECT|O_SYNC along with O_CREAT on open(2), CREATE_NO_BUFFER and CREATE_WRITE_THROUGH bits were missed in CREATE request when performing an atomic open, thus leading to potentially data integrity issues. Fix this by setting those missing bits in CREATE request when O_DIRECT|O_SYNC has been specified in cifs_do_create(). Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Paulo Alcantara (Red Hat) Reviewed-by: David Howells Acked-by: Henrique Carvalho Cc: Tom Talpey Cc: linux-cifs@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

cifs: make default value of retrans as zero

2026-03-25T10:05:54+00:00

commit e3beefd3af09f8e460ddaf39063d3d7664d7ab59 upstream. When retrans mount option was introduced, the default value was set as 1. However, in the light of some bugs that this has exposed recently we should change it to 0 and retain the old behaviour before this option was introduced. Cc: Reviewed-by: Bharath SM Signed-off-by: Shyam Prasad N Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb/client: fix buffer size for smb311_posix_qinfo in SMB311_posix_query_info()

2026-03-25T10:05:41+00:00

[ Upstream commit 9621b996e4db1dbc2b3dc5d5910b7d6179397320 ] SMB311_posix_query_info() is currently unused, but it may still be used in some stable versions, so these changes are submitted as a separate patch. Use `sizeof(struct smb311_posix_qinfo)` instead of sizeof its pointer, so the allocated buffer matches the actual struct size. Fixes: b1bc1874b885 ("smb311: Add support for SMB311 query info (non-compounded)") Reported-by: ChenXiaoSong Signed-off-by: ZhangGuoDong Reviewed-by: ChenXiaoSong Signed-off-by: Steve French Signed-off-by: Sasha Levin

smb/client: fix buffer size for smb311_posix_qinfo in smb2_compound_op()

2026-03-25T10:05:41+00:00

[ Upstream commit 12c43a062acb0ac137fc2a4a106d4d084b8c5416 ] Use `sizeof(struct smb311_posix_qinfo)` instead of sizeof its pointer, so the allocated buffer matches the actual struct size. Fixes: 6a5f6592a0b6 ("SMB311: Add support for query info using posix extensions (level 100)") Reported-by: ChenXiaoSong Signed-off-by: ZhangGuoDong Reviewed-by: ChenXiaoSong Signed-off-by: Steve French Signed-off-by: Sasha Levin

smb: client: Don't log plaintext credentials in cifs_set_cifscreds

2026-03-25T10:05:37+00:00

commit 2f37dc436d4e61ff7ae0b0353cf91b8c10396e4d upstream. When debug logging is enabled, cifs_set_cifscreds() logs the key payload and exposes the plaintext username and password. Remove the debug log to avoid exposing credentials. Fixes: 8a8798a5ff90 ("cifs: fetch credentials out of keyring for non-krb5 auth multiuser mounts") Cc: stable@vger.kernel.org Acked-by: Paulo Alcantara (Red Hat) Signed-off-by: Thorsten Blum Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman