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| author | Eric Biggers <ebiggers@kernel.org> | 2026-02-18 07:28:29 +0300 |
|---|---|---|
| committer | Sasha Levin <sashal@kernel.org> | 2026-03-12 14:09:35 +0300 |
| commit | f4588b85efd6007d46b80aa1b9fb746628ffb3dc (patch) | |
| tree | efe4a486d180c89b4ddd949459eff5a9b4d31488 | |
| parent | 547d0b07ad73915b323bc21f85c5d3252bebbbcf (diff) | |
| download | linux-f4588b85efd6007d46b80aa1b9fb746628ffb3dc.tar.xz | |
ksmbd: Compare MACs in constant time
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 <ebiggers@kernel.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/smb/server/Kconfig | 1 | ||||
| -rw-r--r-- | fs/smb/server/auth.c | 4 | ||||
| -rw-r--r-- | fs/smb/server/smb2pdu.c | 5 |
3 files changed, 7 insertions, 3 deletions
diff --git a/fs/smb/server/Kconfig b/fs/smb/server/Kconfig index 2775162c535c..12594879cb64 100644 --- a/fs/smb/server/Kconfig +++ b/fs/smb/server/Kconfig @@ -13,6 +13,7 @@ config SMB_SERVER select CRYPTO_LIB_MD5 select CRYPTO_LIB_SHA256 select CRYPTO_LIB_SHA512 + select CRYPTO_LIB_UTILS select CRYPTO_CMAC select CRYPTO_AEAD2 select CRYPTO_CCM diff --git a/fs/smb/server/auth.c b/fs/smb/server/auth.c index 09af55b71153..a69e8694605a 100644 --- a/fs/smb/server/auth.c +++ b/fs/smb/server/auth.c @@ -15,6 +15,7 @@ #include <crypto/aead.h> #include <crypto/md5.h> #include <crypto/sha2.h> +#include <crypto/utils.h> #include <linux/random.h> #include <linux/scatterlist.h> @@ -165,7 +166,8 @@ int ksmbd_auth_ntlmv2(struct ksmbd_conn *conn, struct ksmbd_session *sess, ntlmv2_rsp, CIFS_HMAC_MD5_HASH_SIZE, sess->sess_key); - if (memcmp(ntlmv2->ntlmv2_hash, ntlmv2_rsp, CIFS_HMAC_MD5_HASH_SIZE) != 0) + if (crypto_memneq(ntlmv2->ntlmv2_hash, ntlmv2_rsp, + CIFS_HMAC_MD5_HASH_SIZE)) return -EINVAL; return 0; } diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index 1022d794bd23..b682e8160504 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -4,6 +4,7 @@ * Copyright (C) 2018 Samsung Electronics Co., Ltd. */ +#include <crypto/utils.h> #include <linux/inetdevice.h> #include <net/addrconf.h> #include <linux/syscalls.h> @@ -8879,7 +8880,7 @@ int smb2_check_sign_req(struct ksmbd_work *work) ksmbd_sign_smb2_pdu(work->conn, work->sess->sess_key, iov, 1, signature); - if (memcmp(signature, signature_req, SMB2_SIGNATURE_SIZE)) { + if (crypto_memneq(signature, signature_req, SMB2_SIGNATURE_SIZE)) { pr_err("bad smb2 signature\n"); return 0; } @@ -8967,7 +8968,7 @@ int smb3_check_sign_req(struct ksmbd_work *work) if (ksmbd_sign_smb3_pdu(conn, signing_key, iov, 1, signature)) return 0; - if (memcmp(signature, signature_req, SMB2_SIGNATURE_SIZE)) { + if (crypto_memneq(signature, signature_req, SMB2_SIGNATURE_SIZE)) { pr_err("bad smb2 signature\n"); return 0; } |