ksmbd: Compare MACs in constant time
Subsystems (4)
PATCH 1/1 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")
Signed-off-by Eric Biggers <[email protected]>
Acked-by Namjae Jeon <[email protected]>
Signed-off-by Steve French <[email protected]>
--- fs/smb/server/Kconfig | 1 + fs/smb/server/auth.c | 4 +++- fs/smb/server/smb2pdu.c | 5 +++-- 3 files changed, 7 insertions(+), 3 deletions(-)
fs/smb/server/Kconfig +1 -0
@@ -11,10 +11,11 @@ config SMB_SERVER select CRYPTO_HMAC select CRYPTO_ECB 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 select CRYPTO_AEAD2 select CRYPTO_CCM
fs/smb/server/auth.c +3 -1
@@ -11,10 +11,11 @@#include <linux/writeback.h> #include <linux/uio.h> #include <linux/xattr.h> #include <crypto/hash.h> #include <crypto/aead.h> +#include <crypto/utils.h> #include <linux/random.h> #include <linux/scatterlist.h> #include "auth.h" #include "glob.h"
@@ -281,11 +282,12 @@ int ksmbd_auth_ntlmv2(struct ksmbd_conn *conn, struct ksmbd_session *sess,if (rc) {ksmbd_debug (AUTH ,"Could not generate sess key\n" ); 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)ksmbd_release_crypto_ctx (ctx);kfree (construct);
fs/smb/server/smb2pdu.c +3 -2
@@ -2,10 +2,11 @@/* * Copyright (C) 2016 Namjae Jeon <[email protected]> * Copyright (C) 2018 Samsung Electronics Co., Ltd. */ +#include <crypto/utils.h> #include <linux/inetdevice.h> #include <net/addrconf.h> #include <linux/syscalls.h> #include <linux/namei.h> #include <linux/statfs.h>
@@ -8879,11 +8880,11 @@ int smb2_check_sign_req(struct ksmbd_work *work)if (ksmbd_sign_smb2_pdu (work->conn, work->sess->sess_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 ; }return 1 ;
@@ -8967,11 +8968,11 @@ int smb3_check_sign_req(struct ksmbd_work *work) iov[0 ].iov_len = len;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 ; }return 1 ;
base-commit: 6258e292d7463f96d0f06dff2a39093a54c9d16f
Signature · 1 line
2.53.0