diff options
| author | Eric Biggers <ebiggers@kernel.org> | 2026-03-10 12:52:14 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-03-19 16:08:50 +0100 |
| commit | 93c0a22fec914ec4b697e464895a0f594e29fb28 (patch) | |
| tree | db750935c9ed4a19cb4cd6bc749f93cf8ace21e3 | |
| parent | 4af5dfb8dca3a6ad18feb6b2adcfffb4dc874e50 (diff) | |
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 098cac98d31e..6200c71298f6 100644 --- a/fs/smb/server/Kconfig +++ b/fs/smb/server/Kconfig @@ -13,6 +13,7 @@ config SMB_SERVER select CRYPTO_LIB_ARC4 select CRYPTO_LIB_DES select CRYPTO_LIB_SHA256 + select CRYPTO_LIB_UTILS select CRYPTO_SHA256 select CRYPTO_CMAC select CRYPTO_SHA512 diff --git a/fs/smb/server/auth.c b/fs/smb/server/auth.c index b4020bb55a26..f92b2f3dc6de 100644 --- a/fs/smb/server/auth.c +++ b/fs/smb/server/auth.c @@ -13,6 +13,7 @@ #include <linux/xattr.h> #include <crypto/hash.h> #include <crypto/aead.h> +#include <crypto/utils.h> #include <linux/random.h> #include <linux/scatterlist.h> @@ -283,7 +284,8 @@ int ksmbd_auth_ntlmv2(struct ksmbd_conn *conn, struct ksmbd_session *sess, goto out; } - 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)) rc = -EINVAL; out: if (ctx) diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index aa020185bb52..b6915e2c636d 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> @@ -8881,7 +8882,7 @@ int smb2_check_sign_req(struct ksmbd_work *work) 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; } @@ -8969,7 +8970,7 @@ 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; } |