kernel/linux.git/fs/smb, branch v6.1.175

cifs: Fix busy dentry used after unmounting

2026-06-01T15:39:36+00:00

commit c68337442f03953237a94577beb468ab2662a851 upstream. Since commit 340cea84f691c ("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: 340cea84f691c ("cifs: open files should not hold ref on superblock") Cc: stable@vger.kernel.org Reviewed-by: Shyam Prasad N Signed-off-by: Zhihao Cheng Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: client: reject userspace cifs.spnego descriptions

2026-06-01T15:39:34+00:00

commit 3da1fdf4efbc490041eb4f836bf596201203f8f2 upstream. 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: f1d662a7d5e5 ("[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 Signed-off-by: Asim Viladi Oglu Manizada Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb/client: fix possible infinite loop and oob read in symlink_data()

2026-06-01T15:39:32+00:00

commit 7d9a7f1f96cd617ee9e75bb22217c709038e26b8 upstream. 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 Fixes: 76894f3e2f71 ("cifs: improve symlink handling for smb2+") Cc: stable@vger.kernel.org Signed-off-by: Ye Bin Reviewed-by: ChenXiaoSong Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: client: fix OOB reads parsing symlink error response

2026-06-01T15:39:31+00:00

[ Upstream commit 3df690bba28edec865cf7190be10708ad0ddd67e ] When a CREATE returns STATUS_STOPPED_ON_SYMLINK, smb2_check_message() returns success without any length validation, leaving the symlink parsers as the only defense against an untrusted server. symlink_data() walks SMB 3.1.1 error contexts with the loop test "p < end", but reads p->ErrorId at offset 4 and p->ErrorDataLength at offset 0. When the server-controlled ErrorDataLength advances p to within 1-7 bytes of end, the next iteration will read past it. When the matching context is found, sym->SymLinkErrorTag is read at offset 4 from p->ErrorContextData with no check that the symlink header itself fits. smb2_parse_symlink_response() then bounds-checks the substitute name using SMB2_SYMLINK_STRUCT_SIZE as the offset of PathBuffer from iov_base. That value is computed as sizeof(smb2_err_rsp) + sizeof(smb2_symlink_err_rsp), which is correct only when ErrorContextCount == 0. With at least one error context the symlink data sits 8 bytes deeper, and each skipped non-matching context shifts it further by 8 + ALIGN(ErrorDataLength, 8). The check is too short, allowing the substitute name read to run past iov_len. The out-of-bound heap bytes are UTF-16-decoded into the symlink target and returned to userspace via readlink(2). Fix this all up by making the loops test require the full context header to fit, rejecting sym if its header runs past end, and bound the substitute name against the actual position of sym->PathBuffer rather than a fixed offset. Because sub_offs and sub_len are 16bits, the pointer math will not overflow here with the new greater-than. Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Bharath SM Cc: linux-cifs@vger.kernel.org Cc: samba-technical@lists.samba.org Cc: stable Reviewed-by: Paulo Alcantara (Red Hat) Assisted-by: gregkh_clanker_t1000 Signed-off-by: Greg Kroah-Hartman Signed-off-by: Steve French Signed-off-by: Alva Lan Signed-off-by: Sasha Levin

smb: client: correctly handle ErrorContextData as a flexible array

2026-06-01T15:39:30+00:00

[ Upstream commit 215b7f9ecb8d7c14d56febdcdd246f3579c32aba ] The `smb2_symlink_err_rsp` structure was previously defined with `ErrorContextData` as a single `__u8` byte. However, the `ErrorContextData` field is intended to be a variable-length array based on `ErrorDataLength`. This mismatch leads to incorrect pointer arithmetic and potential memory access issues when processing error contexts. Updates the `ErrorContextData` field to be a flexible array (`__u8 ErrorContextData[]`). Additionally, it modifies the corresponding casts in the `symlink_data()` function to properly handle the flexible array, ensuring correct memory calculations and data handling. These changes improve the robustness of SMB2 symlink error processing. Signed-off-by: Liang Jie Suggested-by: Tom Talpey Signed-off-by: Steve French [ Remove the __counted_by_le annotation in v6.1. ] Signed-off-by: Alva Lan Signed-off-by: Sasha Levin

ksmbd: scope conn->binding slowpath to bound sessions only

2026-06-01T15:39:25+00:00

[ Upstream commit b0da97c034b6107d14e537e212d4ce8b22109a58 ] When the binding SESSION_SETUP sets conn->binding = true, the flag stays set after the call so that the global session lookup in ksmbd_session_lookup_all() can find the session, which was not added to conn->sessions. Because the flag is connection-wide, the global lookup path will also resolve any other session by id if asked. Tighten the global lookup so that the returned session must have this connection registered in its channel xarray (sess->ksmbd_chann_list). The channel entry is installed by the existing binding_session path in ntlm_authenticate()/krb5_authenticate() when a SESSION_SETUP completes successfully, so this condition is a strict equivalent of "this connection has been accepted as a channel of this session". Connections that have not bound to a given session cannot reach it via the global table. The existing conn->binding gate for entering the slowpath is preserved so that non-binding connections keep the fast-path-only behavior, and the session->state check is unchanged. Fixes: f5a544e3bab7 ("ksmbd: add support for SMB3 multichannel") Signed-off-by: Hyunwoo Kim Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Sasha Levin

ksmbd: destroy tree_conn_ida in ksmbd_session_destroy()

2026-06-01T15:39:25+00:00

[ Upstream commit c049ee14eb4343b69b6f7755563f961f5e153423 ] When per-session tree_conn_ida was converted from a dynamically allocated ksmbd_ida to an embedded struct ida, ksmbd_ida_free() was removed from ksmbd_session_destroy() but no matching ida_destroy() was added. The session is therefore freed with the IDA's backing xarray still intact. The kernel IDA API expects ida_init() and ida_destroy() to be paired over an object's lifetime, so add the missing cleanup before the enclosing session is freed. Also move ida_init() to right after the session is allocated so that it is always paired with the destroy call even on the early error paths of __session_create() (ksmbd_init_file_table() or __init_smb2_session() failures), both of which jump to the error label and invoke ksmbd_session_destroy() on a partially initialised session. No leak has been observed in testing; this is a pairing fix to match the IDA lifetime rules, not a response to a reproduced regression. Fixes: d40012a83f87 ("cifsd: declare ida statically") Signed-off-by: DaeMyung Kang Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Sasha Levin

ksmbd: fix use-after-free from async crypto on Qualcomm crypto engine

2026-06-01T15:39:14+00:00

[ Upstream commit 3e298897f41c61450c2e7a4f457e8b2485eb35b3 ] ksmbd_crypt_message() sets a NULL completion callback on AEAD requests and does not handle the -EINPROGRESS return code from async hardware crypto engines like the Qualcomm Crypto Engine (QCE). When QCE returns -EINPROGRESS, ksmbd treats it as an error and immediately frees the request while the hardware DMA operation is still in flight. The DMA completion callback then dereferences freed memory, causing a NULL pointer crash: pc : qce_skcipher_done+0x24/0x174 lr : vchan_complete+0x230/0x27c ... el1h_64_irq+0x68/0x6c ksmbd_free_work_struct+0x20/0x118 [ksmbd] ksmbd_exit_file_cache+0x694/0xa4c [ksmbd] Use the standard crypto_wait_req() pattern with crypto_req_done() as the completion callback, matching the approach used by the SMB client in fs/smb/client/smb2ops.c. This properly handles both synchronous engines (immediate return) and async engines (-EINPROGRESS followed by callback notification). Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Link: https://github.com/openwrt/openwrt/issues/21822 Signed-off-by: Joshua Klinesmith Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Sasha Levin

smb/client: fix out-of-bounds read in symlink_data()

2026-06-01T15:38:59+00:00

commit d62b8d236fab503c6fec1d3e9a38bea71feaca20 upstream. Since smb2_check_message() returns success without length validation for the symlink error response, in symlink_data() it is possible for iov->iov_len to be smaller than sizeof(struct smb2_err_rsp). If the buffer only contains the base SMB2 header (64 bytes), accessing err->ErrorContextCount (at offset 66) or err->ByteCount later in symlink_data() will cause an out-of-bounds read. Link: https://lore.kernel.org/linux-cifs/297d8d9b-adf7-42fd-a1c2-5b1f230032bc@chenxiaosong.com/ Fixes: 76894f3e2f71 ("cifs: improve symlink handling for smb2+") Cc: Stable@vger.kernel.org Signed-off-by: Zisen Ye Reviewed-by: ChenXiaoSong Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

cifs: change_conf needs to be called for session setup

2026-06-01T15:38:56+00:00

commit c208a2b95811d6e1ebae65d0d2fc13f73707f8e7 upstream. Today we skip calling change_conf for negotiates and session setup requests. This can be a problem for mchan as the immediate next call after session setup could be due to an I/O that is made on the mount point. For single channel, this is not a problem as there will be several calls after setting up session. This change enforces calling change_conf when the total credits contain enough for reservations for echoes and oplocks. We expect this to happen during the last session setup response. This way, echoes and oplocks are not disabled before the first request to the server. So if that first request is an open, it does not need to disable requesting leases. Cc: Reviewed-by: Bharath SM Signed-off-by: Shyam Prasad N Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman