kernel/fs/smb, branch master

Merge tag 'v7.0-rc4-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6

2026-03-20T16:07:29Z

Pull smb client fixes from Steve French: - Fix reporting of i_blocks - Fix Kerberos mounts with different usernames to same server - Trivial comment cleanup * tag 'v7.0-rc4-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6: smb: client: fix generic/694 due to wrong ->i_blocks cifs: smb1: fix comment typo smb: client: fix krb5 mount with username option

smb: client: fix generic/694 due to wrong ->i_blocks

2026-03-19T18:56:25Z

When updating ->i_size, make sure to always update ->i_blocks as well until we query new allocation size from the server. generic/694 was failing because smb3_simple_falloc() was missing the update of ->i_blocks after calling cifs_setsize(). So, fix this by updating ->i_blocks directly in cifs_setsize(), so all places that call it doesn't need to worry about updating ->i_blocks later. Reported-by: Shyam Prasad N Closes: https://lore.kernel.org/r/CANT5p=rqgRwaADB=b_PhJkqXjtfq3SFv41SSTXSVEHnuh871pA@mail.gmail.com Signed-off-by: Paulo Alcantara (Red Hat) Cc: David Howells Cc: linux-cifs@vger.kernel.org Signed-off-by: Steve French

ksmbd: fix use-after-free in durable v2 replay of active file handles

2026-03-18T02:45:29Z

parse_durable_handle_context() unconditionally assigns dh_info->fp->conn to the current connection when handling a DURABLE_REQ_V2 context with SMB2_FLAGS_REPLAY_OPERATION. ksmbd_lookup_fd_cguid() does not filter by fp->conn, so it returns file handles that are already actively connected. The unconditional overwrite replaces fp->conn, and when the overwriting connection is subsequently freed, __ksmbd_close_fd() dereferences the stale fp->conn via spin_lock(&fp->conn->llist_lock), causing a use-after-free. KASAN report: [ 7.349357] ================================================================== [ 7.349607] BUG: KASAN: slab-use-after-free in _raw_spin_lock+0x75/0xe0 [ 7.349811] Write of size 4 at addr ffff8881056ac18c by task kworker/1:2/108 [ 7.350010] [ 7.350064] CPU: 1 UID: 0 PID: 108 Comm: kworker/1:2 Not tainted 7.0.0-rc3+ #58 PREEMPTLAZY [ 7.350068] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 7.350070] Workqueue: ksmbd-io handle_ksmbd_work [ 7.350083] Call Trace: [ 7.350087] [ 7.350087] dump_stack_lvl+0x64/0x80 [ 7.350094] print_report+0xce/0x660 [ 7.350100] ? __pfx__raw_spin_lock_irqsave+0x10/0x10 [ 7.350101] ? __pfx___mod_timer+0x10/0x10 [ 7.350106] ? _raw_spin_lock+0x75/0xe0 [ 7.350108] kasan_report+0xce/0x100 [ 7.350109] ? _raw_spin_lock+0x75/0xe0 [ 7.350114] kasan_check_range+0x105/0x1b0 [ 7.350116] _raw_spin_lock+0x75/0xe0 [ 7.350118] ? __pfx__raw_spin_lock+0x10/0x10 [ 7.350119] ? __call_rcu_common.constprop.0+0x25e/0x780 [ 7.350125] ? close_id_del_oplock+0x2cc/0x4e0 [ 7.350128] __ksmbd_close_fd+0x27f/0xaf0 [ 7.350131] ksmbd_close_fd+0x135/0x1b0 [ 7.350133] smb2_close+0xb19/0x15b0 [ 7.350142] ? __pfx_smb2_close+0x10/0x10 [ 7.350143] ? xas_load+0x18/0x270 [ 7.350146] ? _raw_spin_lock+0x84/0xe0 [ 7.350148] ? __pfx__raw_spin_lock+0x10/0x10 [ 7.350150] ? _raw_spin_unlock+0xe/0x30 [ 7.350151] ? ksmbd_smb2_check_message+0xeb2/0x24c0 [ 7.350153] ? ksmbd_tree_conn_lookup+0xcd/0xf0 [ 7.350154] handle_ksmbd_work+0x40f/0x1080 [ 7.350156] process_one_work+0x5fa/0xef0 [ 7.350162] ? assign_work+0x122/0x3e0 [ 7.350163] worker_thread+0x54b/0xf70 [ 7.350165] ? __pfx_worker_thread+0x10/0x10 [ 7.350166] kthread+0x346/0x470 [ 7.350170] ? recalc_sigpending+0x19b/0x230 [ 7.350176] ? __pfx_kthread+0x10/0x10 [ 7.350178] ret_from_fork+0x4fb/0x6c0 [ 7.350183] ? __pfx_ret_from_fork+0x10/0x10 [ 7.350185] ? __switch_to+0x36c/0xbe0 [ 7.350188] ? __pfx_kthread+0x10/0x10 [ 7.350190] ret_from_fork_asm+0x1a/0x30 [ 7.350197] [ 7.350197] [ 7.355160] Allocated by task 123: [ 7.355261] kasan_save_stack+0x33/0x60 [ 7.355373] kasan_save_track+0x14/0x30 [ 7.355484] __kasan_kmalloc+0x8f/0xa0 [ 7.355593] ksmbd_conn_alloc+0x44/0x6d0 [ 7.355711] ksmbd_kthread_fn+0x243/0xd70 [ 7.355839] kthread+0x346/0x470 [ 7.355942] ret_from_fork+0x4fb/0x6c0 [ 7.356051] ret_from_fork_asm+0x1a/0x30 [ 7.356164] [ 7.356214] Freed by task 134: [ 7.356305] kasan_save_stack+0x33/0x60 [ 7.356416] kasan_save_track+0x14/0x30 [ 7.356527] kasan_save_free_info+0x3b/0x60 [ 7.356646] __kasan_slab_free+0x43/0x70 [ 7.356761] kfree+0x1ca/0x430 [ 7.356862] ksmbd_tcp_disconnect+0x59/0xe0 [ 7.356993] ksmbd_conn_handler_loop+0x77e/0xd40 [ 7.357138] kthread+0x346/0x470 [ 7.357240] ret_from_fork+0x4fb/0x6c0 [ 7.357350] ret_from_fork_asm+0x1a/0x30 [ 7.357463] [ 7.357513] The buggy address belongs to the object at ffff8881056ac000 [ 7.357513] which belongs to the cache kmalloc-1k of size 1024 [ 7.357857] The buggy address is located 396 bytes inside of [ 7.357857] freed 1024-byte region [ffff8881056ac000, ffff8881056ac400) Fix by removing the unconditional fp->conn assignment and rejecting the replay when fp->conn is non-NULL. This is consistent with ksmbd_lookup_durable_fd(), which also rejects file handles with a non-NULL fp->conn. For disconnected file handles (fp->conn == NULL), ksmbd_reopen_durable_fd() handles setting fp->conn. Fixes: c8efcc786146 ("ksmbd: add support for durable handles v1/v2") Signed-off-by: Hyunwoo Kim Acked-by: Namjae Jeon Signed-off-by: Steve French

ksmbd: fix use-after-free of share_conf in compound request

2026-03-18T02:45:29Z

smb2_get_ksmbd_tcon() reuses work->tcon in compound requests without validating tcon->t_state. ksmbd_tree_conn_lookup() checks t_state == TREE_CONNECTED on the initial lookup path, but the compound reuse path bypasses this check entirely. If a prior command in the compound (SMB2_TREE_DISCONNECT) sets t_state to TREE_DISCONNECTED and frees share_conf via ksmbd_share_config_put(), subsequent commands dereference the freed share_conf through work->tcon->share_conf. KASAN report: [ 4.144653] ================================================================== [ 4.145059] BUG: KASAN: slab-use-after-free in smb2_write+0xc74/0xe70 [ 4.145415] Read of size 4 at addr ffff88810430c194 by task kworker/1:1/44 [ 4.145772] [ 4.145867] CPU: 1 UID: 0 PID: 44 Comm: kworker/1:1 Not tainted 7.0.0-rc3+ #60 PREEMPTLAZY [ 4.145871] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 4.145875] Workqueue: ksmbd-io handle_ksmbd_work [ 4.145888] Call Trace: [ 4.145892] [ 4.145894] dump_stack_lvl+0x64/0x80 [ 4.145910] print_report+0xce/0x660 [ 4.145919] ? __pfx__raw_spin_lock_irqsave+0x10/0x10 [ 4.145928] ? smb2_write+0xc74/0xe70 [ 4.145931] kasan_report+0xce/0x100 [ 4.145934] ? smb2_write+0xc74/0xe70 [ 4.145937] smb2_write+0xc74/0xe70 [ 4.145939] ? __pfx_smb2_write+0x10/0x10 [ 4.145942] ? _raw_spin_unlock+0xe/0x30 [ 4.145945] ? ksmbd_smb2_check_message+0xeb2/0x24c0 [ 4.145948] ? smb2_tree_disconnect+0x31c/0x480 [ 4.145951] handle_ksmbd_work+0x40f/0x1080 [ 4.145953] process_one_work+0x5fa/0xef0 [ 4.145962] ? assign_work+0x122/0x3e0 [ 4.145964] worker_thread+0x54b/0xf70 [ 4.145967] ? __pfx_worker_thread+0x10/0x10 [ 4.145970] kthread+0x346/0x470 [ 4.145976] ? recalc_sigpending+0x19b/0x230 [ 4.145980] ? __pfx_kthread+0x10/0x10 [ 4.145984] ret_from_fork+0x4fb/0x6c0 [ 4.145992] ? __pfx_ret_from_fork+0x10/0x10 [ 4.145995] ? __switch_to+0x36c/0xbe0 [ 4.145999] ? __pfx_kthread+0x10/0x10 [ 4.146003] ret_from_fork_asm+0x1a/0x30 [ 4.146013] [ 4.146014] [ 4.149858] Allocated by task 44: [ 4.149953] kasan_save_stack+0x33/0x60 [ 4.150061] kasan_save_track+0x14/0x30 [ 4.150169] __kasan_kmalloc+0x8f/0xa0 [ 4.150274] ksmbd_share_config_get+0x1dd/0xdd0 [ 4.150401] ksmbd_tree_conn_connect+0x7e/0x600 [ 4.150529] smb2_tree_connect+0x2e6/0x1000 [ 4.150645] handle_ksmbd_work+0x40f/0x1080 [ 4.150761] process_one_work+0x5fa/0xef0 [ 4.150873] worker_thread+0x54b/0xf70 [ 4.150978] kthread+0x346/0x470 [ 4.151071] ret_from_fork+0x4fb/0x6c0 [ 4.151176] ret_from_fork_asm+0x1a/0x30 [ 4.151286] [ 4.151332] Freed by task 44: [ 4.151418] kasan_save_stack+0x33/0x60 [ 4.151526] kasan_save_track+0x14/0x30 [ 4.151634] kasan_save_free_info+0x3b/0x60 [ 4.151751] __kasan_slab_free+0x43/0x70 [ 4.151861] kfree+0x1ca/0x430 [ 4.151952] __ksmbd_tree_conn_disconnect+0xc8/0x190 [ 4.152088] smb2_tree_disconnect+0x1cd/0x480 [ 4.152211] handle_ksmbd_work+0x40f/0x1080 [ 4.152326] process_one_work+0x5fa/0xef0 [ 4.152438] worker_thread+0x54b/0xf70 [ 4.152545] kthread+0x346/0x470 [ 4.152638] ret_from_fork+0x4fb/0x6c0 [ 4.152743] ret_from_fork_asm+0x1a/0x30 [ 4.152853] [ 4.152900] The buggy address belongs to the object at ffff88810430c180 [ 4.152900] which belongs to the cache kmalloc-96 of size 96 [ 4.153226] The buggy address is located 20 bytes inside of [ 4.153226] freed 96-byte region [ffff88810430c180, ffff88810430c1e0) [ 4.153549] [ 4.153596] The buggy address belongs to the physical page: [ 4.153750] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88810430ce80 pfn:0x10430c [ 4.154000] flags: 0x100000000000200(workingset|node=0|zone=2) [ 4.154160] page_type: f5(slab) [ 4.154251] raw: 0100000000000200 ffff888100041280 ffff888100040110 ffff888100040110 [ 4.154461] raw: ffff88810430ce80 0000000800200009 00000000f5000000 0000000000000000 [ 4.154668] page dumped because: kasan: bad access detected [ 4.154820] [ 4.154866] Memory state around the buggy address: [ 4.155002] ffff88810430c080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 4.155196] ffff88810430c100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 4.155391] >ffff88810430c180: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc [ 4.155587] ^ [ 4.155693] ffff88810430c200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 4.155891] ffff88810430c280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 4.156087] ================================================================== Add the same t_state validation to the compound reuse path, consistent with ksmbd_tree_conn_lookup(). Fixes: 5005bcb42191 ("ksmbd: validate session id and tree id in the compound request") Signed-off-by: Hyunwoo Kim Acked-by: Namjae Jeon Signed-off-by: Steve French

ksmbd: use volume UUID in FS_OBJECT_ID_INFORMATION

2026-03-18T02:45:29Z

Use sb->s_uuid for a proper volume identifier as the primary choice. For filesystems that do not provide a UUID, fall back to stfs.f_fsid obtained from vfs_statfs(). Cc: stable@vger.kernel.org Reported-by: Hyunwoo Kim Signed-off-by: Namjae Jeon Signed-off-by: Steve French

ksmbd: unset conn->binding on failed binding request

2026-03-18T02:45:29Z

When a multichannel SMB2_SESSION_SETUP request with SMB2_SESSION_REQ_FLAG_BINDING fails ksmbd sets conn->binding = true but never clears it on the error path. This leaves the connection in a binding state where all subsequent ksmbd_session_lookup_all() calls fall back to the global sessions table. This fix it by clearing conn->binding = false in the error path. Cc: stable@vger.kernel.org Reported-by: Hyunwoo Kim Signed-off-by: Namjae Jeon Signed-off-by: Steve French

ksmbd: fix share_conf UAF in tree_conn disconnect

2026-03-18T02:45:29Z

__ksmbd_tree_conn_disconnect() drops the share_conf reference before checking tree_conn->refcount. When someone uses SMB3 multichannel and binds two connections to one session, a SESSION_LOGOFF on connection A calls ksmbd_conn_wait_idle(conn) which only drains connection A's request counter, not connection B's. This means there's a race condition: requests already dispatched on connection B hold tree_conn references via work->tcon. The disconnect path frees share_conf while those requests are still walking work->tcon->share_conf, causing a use-after-free. This fix combines the share_conf put with the tree_conn free so it only happens when the last reference is dropped. Fixes: b39a1833cc4a ("ksmbd: fix use-after-free in ksmbd_tree_connect_put under concurrency") Signed-off-by: Nicholas Carlini Acked-by: Namjae Jeon Signed-off-by: Steve French

cifs: smb1: fix comment typo

2026-03-17T02:12:40Z

The file contains a spelling error in a source comment (resposne). Typos in comments reduce readability and make text searches less reliable for developers and maintainers. Replace 'resposne' with 'response' in the affected comment. This is a comment-only cleanup and does not change behavior. [v2: Removed Fixes: and Cc: to stable tags.] Signed-off-by: Joseph Salisbury Signed-off-by: Steve French

smb: client: fix krb5 mount with username option

2026-03-16T01:53:09Z

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

Merge tag 'v7.0-rc3-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6

2026-03-13T17:46:32Z

Pull smb client fixes from Steve French: - Fix reconnect when using non-default port - Fix default retransmission behavior - Fix open handle reuse in cifs_open - Fix export for smb2-mapperror-test - Fix potential corruption on write retry - Fix potentially uninitialized superblock flags - Fix missing O_DIRECT and O_SYNC flags on create * tag 'v7.0-rc3-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6: cifs: make default value of retrans as zero smb: client: fix open handle lookup in cifs_open() smb: client: fix iface port assignment in parse_server_interfaces smb/client: only export symbol for 'smb2maperror-test' module smb: client: fix in-place encryption corruption in SMB2_write() smb: client: fix sbflags initialization smb: client: fix atomic open with O_DIRECT & O_SYNC