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

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

ksmbd: use check_add_overflow() to prevent u16 DACL size overflow

2026-06-01T15:38:42+00:00

commit 299f962c0b02d048fb45d248b4da493d03f3175d upstream. set_posix_acl_entries_dacl() and set_ntacl_dacl() accumulate ACE sizes in u16 variables. When a file has many POSIX ACL entries, the accumulated size can wrap past 65535, causing the pointer arithmetic (char *)pndace + *size to land within already-written ACEs. Subsequent writes then overwrite earlier entries, and pndacl->size gets a truncated value. Use check_add_overflow() at each accumulation point to detect the wrap before it corrupts the buffer, consistent with existing check_mul_overflow() usage elsewhere in smbacl.c. Cc: stable@vger.kernel.org Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Signed-off-by: Tristan Madani Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

ksmbd: fix out-of-bounds write in smb2_get_ea() EA alignment

2026-06-01T15:38:42+00:00

commit 30010c952077a1c89ecdd71fc4d574c75a8f5617 upstream. smb2_get_ea() applies 4-byte alignment padding via memset() after writing each EA entry. The bounds check on buf_free_len is performed before the value memcpy, but the alignment memset fires unconditionally afterward with no check on remaining space. When the EA value exactly fills the remaining buffer (buf_free_len == 0 after value subtraction), the alignment memset writes 1-3 NUL bytes past the buf_free_len boundary. In compound requests where the response buffer is shared across commands, the first command (e.g., READ) can consume most of the buffer, leaving a tight remainder for the QUERY_INFO EA response. The alignment memset then overwrites past the physical kvmalloc allocation into adjacent kernel heap memory. Add a bounds check before the alignment memset to ensure buf_free_len can accommodate the padding bytes. This is the same bug pattern fixed by commit beef2634f81f ("ksmbd: fix potencial OOB in get_file_all_info() for compound requests") and commit fda9522ed6af ("ksmbd: fix OOB write in QUERY_INFO for compound requests"), both of which added bounds checks before unconditional writes in QUERY_INFO response handlers. Cc: stable@vger.kernel.org Fixes: e2b76ab8b5c9 ("ksmbd: add support for read compound") Signed-off-by: Tristan Madani Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: server: fix max_connections off-by-one in tcp accept path

2026-06-01T15:38:42+00:00

commit ce23158bfe584bd90d1918f279fdf9de57802012 upstream. The global max_connections check in ksmbd's TCP accept path counts the newly accepted connection with atomic_inc_return(), but then rejects the connection when the result is greater than or equal to server_conf.max_connections. That makes the effective limit one smaller than configured. For example: - max_connections=1 rejects the first connection - max_connections=2 allows only one connection The per-IP limit in the same function uses <= correctly because it counts only pre-existing connections. The global limit instead checks the post-increment total, so it should reject only when that total exceeds the configured maximum. Fix this by changing the comparison from >= to >, so exactly max_connections simultaneous connections are allowed and the next one is rejected. This matches the documented meaning of max_connections in fs/smb/server/ksmbd_netlink.h as the "Number of maximum simultaneous connections". Fixes: 0d0d4680db22 ("ksmbd: add max connections parameter") Cc: stable@vger.kernel.org Signed-off-by: DaeMyung Kang Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: server: fix active_num_conn leak on transport allocation failure

2026-06-01T15:38:42+00:00

commit 6551300dc452ac16a855a83dbd1e74899542d3b3 upstream. Commit 77ffbcac4e56 ("smb: server: fix leak of active_num_conn in ksmbd_tcp_new_connection()") addressed the kthread_run() failure path. The earlier alloc_transport() == NULL path in the same function has the same leak, is reachable pre-authentication via any TCP connect to port 445, and was empirically reproduced on UML (ARCH=um, v7.0-rc7): a small number of forced allocation failures were sufficient to put ksmbd into a state where every subsequent connection attempt was rejected for the remainder of the boot. ksmbd_kthread_fn() increments active_num_conn before calling ksmbd_tcp_new_connection() and discards the return value, so when alloc_transport() returns NULL the socket is released and -ENOMEM returned without decrementing the counter. Each such failure permanently consumes one slot from the max_connections pool; once cumulative failures reach the cap, atomic_inc_return() hits the threshold on every subsequent accept and every new connection is rejected. The counter is only reset by module reload. An unauthenticated remote attacker can drive the server toward the memory pressure that makes alloc_transport() fail by holding open connections with large RFC1002 lengths up to MAX_STREAM_PROT_LEN (0x00FFFFFF); natural transient allocation failures on a loaded host produce the same drift more slowly. Mirror the existing rollback pattern in ksmbd_kthread_fn(): on the alloc_transport() failure path, decrement active_num_conn gated on server_conf.max_connections. Repro details: with the patch reverted, forced alloc_transport() NULL returns leaked counter slots and subsequent connection attempts -- including legitimate connects issued after the forced-fail window had closed -- were all rejected with "Limit the maximum number of connections". With this patch applied, the same connect sequence produces no rejections and the counter cycles cleanly between zero and one on every accept. Fixes: 0d0d4680db22 ("ksmbd: add max connections parameter") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-6 Assisted-by: Codex:gpt-5-4 Signed-off-by: Michael Bommarito Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

ksmbd: require 3 sub-authorities before reading sub_auth[2]

2026-06-01T15:38:36+00:00

commit 53370cf9090777774e07fd9a8ebce67c6cc333ab upstream. parse_dacl() compares each ACE SID against sid_unix_NFS_mode and on match reads sid.sub_auth[2] as the file mode. If sid_unix_NFS_mode is the prefix S-1-5-88-3 with num_subauth = 2 then compare_sids() compares only min(num_subauth, 2) sub-authorities so a client SID with num_subauth = 2 and sub_auth = {88, 3} will match. If num_subauth = 2 and the ACE is placed at the very end of the security descriptor, sub_auth[2] will be 4 bytes past end_of_acl. The out-of-band bytes will then be masked to the low 9 bits and applied as the file's POSIX mode, probably not something that is good to have happen. Fix this up by forcing the SID to actually carry a third sub-authority before reading it at all. Cc: Namjae Jeon Cc: Steve French Cc: Sergey Senozhatsky Cc: Tom Talpey Cc: linux-cifs@vger.kernel.org Cc: Assisted-by: gregkh_clanker_t1000 Signed-off-by: Greg Kroah-Hartman Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

ksmbd: validate EaNameLength in smb2_get_ea()

2026-06-01T15:38:36+00:00

commit 66751841212c2cc196577453c37f7774ff363f02 upstream. smb2_get_ea() reads ea_req->EaNameLength from the client request and passes it directly to strncmp() as the comparison length without verifying that the length of the name really is the size of the input buffer received. Fix this up by properly checking the size of the name based on the value received and the overall size of the request, to prevent a later strncmp() call to use the length as a "trusted" size of the buffer. Without this check, uninitialized heap values might be slowly leaked to the client. Cc: Namjae Jeon Cc: Steve French Cc: Sergey Senozhatsky Cc: Tom Talpey Cc: linux-cifs@vger.kernel.org Cc: Assisted-by: gregkh_clanker_t1000 Signed-off-by: Greg Kroah-Hartman Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

ksmbd: fix potencial OOB in get_file_all_info() for compound requests

2026-04-11T12:16:35+00:00

[ Upstream commit beef2634f81f1c086208191f7228bce1d366493d ] When a compound request consists of QUERY_DIRECTORY + QUERY_INFO (FILE_ALL_INFORMATION) and the first command consumes nearly the entire max_trans_size, get_file_all_info() would blindly call smbConvertToUTF16() with PATH_MAX, causing out-of-bounds write beyond the response buffer. In get_file_all_info(), there was a missing validation check for the client-provided OutputBufferLength before copying the filename into FileName field of the smb2_file_all_info structure. If the filename length exceeds the available buffer space, it could lead to potential buffer overflows or memory corruption during smbConvertToUTF16 conversion. This calculating the actual free buffer size using smb2_calc_max_out_buf_len() and returning -EINVAL if the buffer is insufficient and updating smbConvertToUTF16 to use the actual filename length (clamped by PATH_MAX) to ensure a safe copy operation. Cc: stable@vger.kernel.org Fixes: e2b76ab8b5c9 ("ksmbd: add support for read compound") Reported-by: Asim Viladi Oglu Manizada Signed-off-by: Namjae Jeon Signed-off-by: Steve French [ adapted variable declarations ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman