linux/fs/smb, branch master

smbdirect: Fix error cleanup in smbdirect_map_sges_from_iter()

2026-05-14T18:21:00Z

Fix smbdirect_map_sges_from_iter() to use pre-decrement, not post-decrement so that it cleans up the correct slots. Fixes: e5fbdde43017 ("cifs: Add a function to build an RDMA SGE list from an iterator") Closes: https://sashiko.dev/#/patchset/20260326104544.509518-1-dhowells%40redhat.com Signed-off-by: David Howells Reviewed-by: Stefan Metzmacher cc: Paulo Alcantara cc: Tom Talpey cc: linux-cifs@vger.kernel.org cc: linux-fsdevel@vger.kernel.org Signed-off-by: Steve French

smb: client: avoid integer overflow in SMB2 READ length check

2026-05-14T15:55:28Z

SMB2 READ response validation in cifs_readv_receive() and handle_read_data() checks data_offset + data_len against the received buffer length. Both values are attacker-controlled fields from the server response and are stored as unsigned int, so the addition can wrap before the bounds check: fs/smb/client/transport.c:1259 if (!use_rdma_mr && (data_offset + data_len > buflen)) fs/smb/client/smb2ops.c:4839 else if (buf_len >= data_offset + data_len) A malicious SMB server can use this to bypass validation. In the non-encrypted receive path the client attempts an oversized socket read and stalls for the SMB response timeout (180 seconds) before reconnecting. In the SMB3 encrypted path, runtime testing shows the malformed length can reach copy_to_iter() in handle_read_data() with attacker-controlled size, where usercopy hardening stops the oversized copy before bytes reach userspace. Guard both call sites with check_add_overflow(), which is already used elsewhere in this subsystem (smb2pdu.c). On overflow, treat the response as malformed and reject with -EIO. Signed-off-by: Jeremy Erazo Signed-off-by: Steve French

cifs: client: stage smb3_reconfigure() updates and restore ctx on failure

2026-05-14T14:41:00Z

smb3_reconfigure() moves strings out of cifs_sb->ctx before the multichannel update, so a later failure can leave the live context with NULL strings or options that do not match the session. Stage the new ctx separately, commit it only on success, and restore the snapshot on failure. Also make smb3_sync_session_ctx_passwords() all-or-nothing. Commit session passwords before channel updates so newly added channels authenticate with the staged credentials. Fixes: ef529f655a2c ("cifs: client: allow changing multichannel mount options on remount") Reported-by: RAJASI MANDAL Closes: https://lore.kernel.org/lkml/CAEY6_V1+dzW3OD5zqXhsWyXwrDTrg5tAMGZ1AJ7_GAuRE+aevA@mail.gmail.com/ Link: https://lore.kernel.org/lkml/xkr2dlvgibq5j6gkcxd3yhhnj4atgxw2uy4eug2pxm7wy7nbms@iq6cf5taa65v/ Reviewed-by: Henrique Carvalho Signed-off-by: DaeMyung Kang Signed-off-by: Steve French

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

2026-05-14T14:40:17Z

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

SMB3.1.1: add missing QUERY_DIR info levels

2026-05-12T15:13:24Z

New Infolevels for QUERY_DIR (and QUERY_INFO) levels 78 through 81 are now being used by Windows clients and were added to the documentation. Add defines for them (and correct some typos in documentation). See MS-SMB2 2.2.33 and MS-FSCC 2.4 Signed-off-by: Steve French

Merge tag 'v7.1-rc3-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6

2026-05-08T17:24:35Z

Pull smb client fixes from Steve French: - Fix for two ACL issues (security fix to validate dacloffset better and chmod fix) - Fix out of bounds reads (in check_wsl_eas and smb2_check_msg for symlinks) - Two Kerberos fixes including an important one when AES-256 encryption chosen - Fix open_cached_dir problem when directory leases disabled * tag 'v7.1-rc3-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6: smb: client: validate dacloffset before building DACL pointers smb/client: fix out-of-bounds read in smb2_compound_op() smb/client: fix out-of-bounds read in symlink_data() smb: client: Zero-pad short GSS session keys per MS-SMB2 smb: client: Use FullSessionKey for AES-256 encryption key derivation smb: client: use kzalloc to zero-initialize security descriptor buffer cifs: abort open_cached_dir if we don't request leases

smb: client: validate dacloffset before building DACL pointers

2026-05-07T19:09:36Z

parse_sec_desc(), build_sec_desc(), and the chown path in id_mode_to_cifs_acl() all add the server-supplied dacloffset to pntsd before proving a DACL header fits inside the returned security descriptor. On 32-bit builds a malicious server can return dacloffset near U32_MAX, wrap the derived DACL pointer below end_of_acl, and then slip past the later pointer-based bounds checks. build_sec_desc() and id_mode_to_cifs_acl() can then dereference DACL fields from the wrapped pointer in the chmod/chown rewrite paths. Validate dacloffset numerically before building any DACL pointer and reuse the same helper at the three DACL entry points. Fixes: bc3e9dd9d104 ("cifs: Change SIDs in ACEs while transferring file ownership.") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-6 Signed-off-by: Michael Bommarito Signed-off-by: Steve French

smb/client: fix out-of-bounds read in smb2_compound_op()

2026-05-07T19:09:32Z

If a server sends a truncated response but a large OutputBufferLength, and terminates the EA list early, check_wsl_eas() returns success without validating that the entire OutputBufferLength fits within iov_len. Then smb2_compound_op() does: memcpy(idata->wsl.eas, data[0], size[0]); Where size[0] is OutputBufferLength. If iov_len is smaller than size[0], memcpy can read beyond the end of the rsp_iov allocation and leak adjacent kernel heap memory. Link: https://lore.kernel.org/linux-cifs/d998240c-aca9-420d-9dbd-f5ba24af19e0@chenxiaosong.com/ Fixes: ea41367b2a60 ("smb: client: introduce SMB2_OP_QUERY_WSL_EA") Cc: stable@vger.kernel.org Signed-off-by: Zisen Ye Reviewed-by: ChenXiaoSong Signed-off-by: Steve French

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

2026-05-07T19:09:29Z

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

smb: client: Zero-pad short GSS session keys per MS-SMB2

2026-05-07T19:09:01Z

Per MS-SMB2 section 3.2.5.3, Session.SessionKey is the first 16 bytes of the GSS cryptographic key, right-padded with zero bytes if the key is shorter than 16 bytes. SMB2_auth_kerberos() copies the GSS session key from the cifs.upcall response using kmemdup(msg->data, msg->sesskey_len, ...) and stores the GSS-reported length verbatim in ses->auth_key.len. generate_key() reads SMB2_NTLMV2_SESSKEY_SIZE bytes from this buffer when feeding the HMAC-SHA256 KDF for signing key derivation. If a GSS mechanism returns a session key shorter than 16 bytes (e.g. a deprecated single-DES Kerberos enctype with an 8-byte session key), the KDF call performs an out-of-bounds slab read and derives keys that do not match the server, which pads per the spec. Modern KDCs disable short-key enctypes by default, so this is latent rather than reachable in production, but it is still a kernel heap over-read. Allocate auth_key.response with kzalloc() at a length of max(msg->sesskey_len, SMB2_NTLMV2_SESSKEY_SIZE), copy the GSS key in, and rely on kzalloc()'s zero initialization for the spec-mandated padding. Set ses->auth_key.len to the padded length. Larger GSS keys (e.g. the 32-byte aes256-cts-hmac-sha1-96 session key) continue to be stored at their natural length, preserving the FullSessionKey path. Emit a cifs_dbg(VFS, ...) message when a short key is encountered to surface deprecated-enctype usage. NTLMv2 and NTLMSSP code paths produce a 16-byte session key by construction and are unaffected. Signed-off-by: Piyush Sachdeva Signed-off-by: Piyush Sachdeva Signed-off-by: Steve French