diff options
| author | Eric Biggers <ebiggers@kernel.org> | 2026-03-02 12:34:09 -0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-03-03 18:39:43 -0800 |
| commit | 46d0d6f50dab706637f4c18a470aac20a21900d3 (patch) | |
| tree | 8b6b7fb5ae167d5d3d2a0f86c83e8db8f5d7144a | |
| parent | 7f5d8e63f3d4dc952548502a2227de780cbcd21f (diff) | |
net/tcp-md5: Fix MAC comparison to be constant-time
To prevent timing attacks, MACs need to be compared in constant
time. Use the appropriate helper function for this.
Fixes: cfb6eeb4c860 ("[TCP]: MD5 Signature Option (RFC2385) support.")
Fixes: 658ddaaf6694 ("tcp: md5: RST: getting md5 key from listener")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Link: https://patch.msgid.link/20260302203409.13388-1-ebiggers@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/ipv4/Kconfig | 1 | ||||
| -rw-r--r-- | net/ipv4/tcp.c | 3 | ||||
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 3 | ||||
| -rw-r--r-- | net/ipv6/tcp_ipv6.c | 3 |
4 files changed, 7 insertions, 3 deletions
diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig index 3ab6247be585..df922f9f5289 100644 --- a/net/ipv4/Kconfig +++ b/net/ipv4/Kconfig @@ -762,6 +762,7 @@ config TCP_AO config TCP_MD5SIG bool "TCP: MD5 Signature Option support (RFC2385)" select CRYPTO_LIB_MD5 + select CRYPTO_LIB_UTILS help RFC2385 specifies a method of giving MD5 protection to TCP sessions. Its main (only?) use is to protect BGP sessions between core routers diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 8cdc26e8ad68..202a4e57a218 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -244,6 +244,7 @@ #define pr_fmt(fmt) "TCP: " fmt #include <crypto/md5.h> +#include <crypto/utils.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/types.h> @@ -4970,7 +4971,7 @@ tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, tcp_v4_md5_hash_skb(newhash, key, NULL, skb); else tp->af_specific->calc_md5_hash(newhash, key, NULL, skb); - if (memcmp(hash_location, newhash, 16) != 0) { + if (crypto_memneq(hash_location, newhash, 16)) { NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE); trace_tcp_hash_md5_mismatch(sk, skb); return SKB_DROP_REASON_TCP_MD5FAILURE; diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index d53d39be291a..910c25cb24e1 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -88,6 +88,7 @@ #include <linux/skbuff_ref.h> #include <crypto/md5.h> +#include <crypto/utils.h> #include <trace/events/tcp.h> @@ -839,7 +840,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb, goto out; tcp_v4_md5_hash_skb(newhash, key, NULL, skb); - if (memcmp(md5_hash_location, newhash, 16) != 0) + if (crypto_memneq(md5_hash_location, newhash, 16)) goto out; } diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index e46a0efae012..5195a46b951e 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -68,6 +68,7 @@ #include <linux/seq_file.h> #include <crypto/md5.h> +#include <crypto/utils.h> #include <trace/events/tcp.h> @@ -1048,7 +1049,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb, key.type = TCP_KEY_MD5; tcp_v6_md5_hash_skb(newhash, key.md5_key, NULL, skb); - if (memcmp(md5_hash_location, newhash, 16) != 0) + if (crypto_memneq(md5_hash_location, newhash, 16)) goto out; } #endif |