kernel/linux.git/fs/smb/client, branch v7.0.10

smb: client: Use FullSessionKey for AES-256 encryption key derivation

2026-05-23T11:09:43+00:00

[ Upstream commit 5be7a0cef3229fb3b63a07c0d289daf752545424 ] When Kerberos authentication is used with AES-256 encryption (AES-256-CCM or AES-256-GCM), the SMB3 encryption and decryption keys must be derived using the full session key (Session.FullSessionKey) rather than just the first 16 bytes (Session.SessionKey). Per MS-SMB2 section 3.2.5.3.1, when Connection.Dialect is "3.1.1" and Connection.CipherId is AES-256-CCM or AES-256-GCM, Session.FullSessionKey must be set to the full cryptographic key from the GSS authentication context. The encryption and decryption key derivation (SMBC2SCipherKey, SMBS2CCipherKey) must use this FullSessionKey as the KDF input. The signing key derivation continues to use Session.SessionKey (first 16 bytes) in all cases. Previously, generate_key() hardcoded SMB2_NTLMV2_SESSKEY_SIZE (16) as the HMAC-SHA256 key input length for all derivations. When Kerberos with AES-256 provides a 32-byte session key, the KDF for encryption/decryption was using only the first 16 bytes, producing keys that did not match the server's, causing mount failures with sec=krb5 and require_gcm_256=1. Add a full_key_size parameter to generate_key() and pass the appropriate size from generate_smb3signingkey(): - Signing: always SMB2_NTLMV2_SESSKEY_SIZE (16 bytes) - Encryption/Decryption: ses->auth_key.len when AES-256, otherwise 16 Also fix cifs_dump_full_key() to report the actual session key length for AES-256 instead of hardcoded CIFS_SESS_KEY_SIZE, so that userspace tools like Wireshark receive the correct key for decryption. Cc: Reviewed-by: Bharath SM Signed-off-by: Piyush Sachdeva Signed-off-by: Piyush Sachdeva Signed-off-by: Steve French Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

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

2026-05-23T11:09:38+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: validate dacloffset before building DACL pointers

2026-05-14T13:31:14+00:00

commit f98b48151cc502ada59d9778f0112d21f2586ca3 upstream. 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 Signed-off-by: Greg Kroah-Hartman

smb: client: use kzalloc to zero-initialize security descriptor buffer

2026-05-14T13:31:14+00:00

commit 5e489c6c47a2ac15edbaca153b9348e42c1eacab upstream. Commit 62e7dd0a39c2d ("smb: common: change the data type of num_aces to le16") split struct smb_acl's __le32 num_aces field into __le16 num_aces and __le16 reserved. The reserved field corresponds to Sbz2 in the MS-DTYP ACL wire format, which must be zero [1]. When building an ACL descriptor in build_sec_desc(), we are using a kmalloc()'ed descriptor buffer and writing the fields explicitly using le16() writes now. This never writes to the 2 byte reserved field, leaving it as uninitialized heap data. When the reserved field happens to contain non-zero slab garbage, Samba rejects the security descriptor with "ndr_pull_security_descriptor failed: Range Error", causing chmod to fail with EINVAL. Change kmalloc() to kzalloc() to ensure the entire buffer is zero-initialized. Fixes: 62e7dd0a39c2d ("smb: common: change the data type of num_aces to le16") Cc: stable@vger.kernel.org Signed-off-by: Bjoern Doebel Assisted-by: Kiro:claude-opus-4.6 [1] https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-dtyp/20233ed8-a6c6-4097-aafa-dd545ed24428 Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

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

2026-05-14T13:31:14+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

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

2026-05-14T13:31:14+00:00

commit 8d09328dfda089675e4c049f3f256064a1d1996b upstream. 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 Signed-off-by: Greg Kroah-Hartman

cifs: change_conf needs to be called for session setup

2026-05-14T13:31:10+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

cifs: abort open_cached_dir if we don't request leases

2026-05-14T13:31:10+00:00

commit d68ce834f8cf6cb2e77f3331df65166b35466b53 upstream. It is possible that SMB2_open_init may not set lease context based on the requested oplock level. This can happen when leases have been temporarily or permanently disabled. When this happens, we will have open_cached_dir making an open without lease context and the response will anyway be rejected by open_cached_dir (thereby forcing a close to discard this open). That's unnecessary two round-trips to the server. This change adds a check before making the open request to the server to make sure that SMB2_open_init did add the expected lease context to the open in open_cached_dir. Cc: Reviewed-by: Bharath SM Signed-off-by: Shyam Prasad N Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: client/smbdirect: fix MR registration for coalesced SG lists

2026-05-14T13:31:03+00:00

commit 9900b9fee5a0e0f72d7c744b37c7c851d5785ac6 upstream. The stable backport to < 7.1 patches a different file. Also the Fixes tag below is adjusted for the old code path. ib_dma_map_sg() modifies the provided scatterlist and returns the number of mapped entries, which can be fewer than the requested mr->sgt.nents if the DMA controller coalesces contiguous memory segments. Passing the original, uncoalesced count to ib_map_mr_sg() causes memory registration failures if coalescing actually occurs. Capture the actual mapped count returned by ib_dma_map_sg() and pass it to ib_map_mr_sg() to ensure correct MR registration. Also update the ib_dma_map_sg() error logging to drop the error pointer formatting, since the return value is an integer count rather than an error code. Ensure a proper error code (-EIO) is assigned when DMA mapping or MR registration fails. Fixes: c7398583340a ("CIFS: SMBD: Implement RDMA memory registration") Closes: https://bugzilla.kernel.org/show_bug.cgi?id=221408 Reviewed-by: Stefan Metzmacher Acked-by: Namjae Jeon Signed-off-by: Yi Kuo Signed-off-by: Steve French Cc: stable@vger.kernel.org Signed-off-by: Stefan Metzmacher Signed-off-by: Sasha Levin

smb: client: fix OOB read in smb2_ioctl_query_info QUERY_INFO path

2026-04-27T13:30:18+00:00

commit a58c5af19ff0d6f44f6e9fe31e33a2c92223f77e upstream. smb2_ioctl_query_info() has two response-copy branches: PASSTHRU_FSCTL and the default QUERY_INFO path. The QUERY_INFO branch clamps qi.input_buffer_length to the server-reported OutputBufferLength and then copies qi.input_buffer_length bytes from qi_rsp->Buffer to userspace, but it never verifies that the flexible-array payload actually fits within rsp_iov[1].iov_len. A malicious server can return OutputBufferLength larger than the actual QUERY_INFO response, causing copy_to_user() to walk past the response buffer and expose adjacent kernel heap to userspace. Guard the QUERY_INFO copy with a bounds check on the actual Buffer payload. Use struct_size(qi_rsp, Buffer, qi.input_buffer_length) rather than an open-coded addition so the guard cannot overflow on 32-bit builds. Fixes: f5778c398713 ("SMB3: Allow SMB3 FSCTL queries to be sent to server from tools") Cc: stable@vger.kernel.org Signed-off-by: Michael Bommarito Assisted-by: Claude:claude-opus-4-6 Assisted-by: Codex:gpt-5-4 Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman