kernel/fs/smb/server/auth.c, branch linux-rolling-stable

ksmbd: Don't log keys in SMB3 signing and encryption key generation

2026-03-19T15:15:22Z

commit 441336115df26b966575de56daf7107ed474faed upstream. When KSMBD_DEBUG_AUTH logging is enabled, generate_smb3signingkey() and generate_smb3encryptionkey() log the session, signing, encryption, and decryption key bytes. Remove the logs to avoid exposing credentials. Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Cc: stable@vger.kernel.org Signed-off-by: Thorsten Blum Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

ksmbd: Compare MACs in constant time

2026-03-12T11:09:35Z

commit c5794709bc9105935dbedef8b9cf9c06f2b559fa upstream. To prevent timing attacks, MAC comparisons need to be constant-time. Replace the memcmp() with the correct function, crypto_memneq(). Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

ksmbd: rename smb2_get_msg to smb_get_msg

2025-12-22T01:20:46Z

With the removal of the RFC1002 length field from the SMB header, smb2_get_msg is now used to get the smb1 request from the request buffer. Since this function is no longer exclusive to smb2 and now supports smb1 as well, This patch rename it to smb_get_msg to better reflect its usage. Signed-off-by: Namjae Jeon Signed-off-by: Steve French

ksmbd: Use HMAC-MD5 library for NTLMv2

2025-12-01T03:11:43Z

For the HMAC-MD5 computations in NTLMv2, use the HMAC-MD5 library instead of a "hmac(md5)" crypto_shash. This is simpler and faster. With the library there's no need to allocate memory, no need to handle errors, and the HMAC-MD5 code is accessed directly without inefficient indirect calls and other unnecessary API overhead. To preserve the existing behavior of NTLMv2 support being disabled when the kernel is booted with "fips=1", make ksmbd_auth_ntlmv2() check fips_enabled itself. Previously it relied on the error from crypto_alloc_shash("hmac(md5)") being bubbled up. I don't know for sure that this is actually needed, but this preserves the existing behavior. Signed-off-by: Eric Biggers Acked-by: Namjae Jeon Signed-off-by: Steve French

ksmbd: Use HMAC-SHA256 library for message signing and key generation

2025-12-01T03:11:43Z

Convert ksmbd_sign_smb2_pdu() and generate_key() to use the HMAC-SHA256 library instead of a "hmac(sha256)" crypto_shash. This is simpler and faster. With the library there's no need to allocate memory, no need to handle errors, and the HMAC-SHA256 code is accessed directly without inefficient indirect calls and other unnecessary API overhead. Signed-off-by: Eric Biggers Acked-by: Namjae Jeon Signed-off-by: Steve French

ksmbd: Use SHA-512 library for SMB3.1.1 preauth hash

2025-12-01T03:11:42Z

Convert ksmbd_gen_preauth_integrity_hash() to use the SHA-512 library instead of a "sha512" crypto_shash. This is simpler and faster. With the library there's no need to allocate memory, no need to handle errors, and the SHA-512 code is accessed directly without inefficient indirect calls and other unnecessary API overhead. Signed-off-by: Eric Biggers Acked-by: Namjae Jeon Signed-off-by: Steve French

smb: Use arc4 library instead of duplicate arc4 code

2025-09-30T02:21:23Z

fs/smb/common/cifs_arc4.c has an implementation of ARC4, but a copy of this same code is also present in lib/crypto/arc4.c to serve the other users of this legacy algorithm in the kernel. Remove the duplicate implementation in fs/smb/, which seems to have been added because of a misunderstanding, and just use the lib/crypto/ one. Signed-off-by: Eric Biggers Reviewed-by: Paulo Alcantara (Red Hat) Signed-off-by: Steve French

ksmbd: use SHA-256 library API instead of crypto_shash API

2025-05-26T03:54:50Z

ksmbd_gen_sd_hash() does not support any other algorithm, so the crypto_shash abstraction provides no value. Just use the SHA-256 library API instead, which is much simpler and easier to use. Signed-off-by: Eric Biggers Acked-by: Namjae Jeon Signed-off-by: Steve French

ksmbd: fix use-after-free in kerberos authentication

2025-04-25T23:22:01Z

Setting sess->user = NULL was introduced to fix the dangling pointer created by ksmbd_free_user. However, it is possible another thread could be operating on the session and make use of sess->user after it has been passed to ksmbd_free_user but before sess->user is set to NULL. Cc: stable@vger.kernel.org Signed-off-by: Sean Heelan Acked-by: Namjae Jeon Signed-off-by: Steve French

ksmbd: fix session use-after-free in multichannel connection

2025-04-01T05:04:21Z

There is a race condition between session setup and ksmbd_sessions_deregister. The session can be freed before the connection is added to channel list of session. This patch check reference count of session before freeing it. Cc: stable@vger.kernel.org Reported-by: Sean Heelan Signed-off-by: Namjae Jeon Signed-off-by: Steve French