diff options
| author | Eric Biggers <ebiggers@kernel.org> | 2026-03-10 13:16:36 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-03-19 16:08:50 +0100 |
| commit | ae3831b44f477de048287493e184fc3ff913b624 (patch) | |
| tree | 5c1cae34fd509ebdc17268d697af3658d9bb2c71 | |
| parent | ce2a263bc57c11c9906990356a5790097e3e1925 (diff) | |
net/tcp-md5: Fix MAC comparison to be constant-time
commit 46d0d6f50dab706637f4c18a470aac20a21900d3 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 |
3 files changed, 6 insertions, 3 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index f665c87edc0f..94e029c70247 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -244,6 +244,7 @@ #define pr_fmt(fmt) "TCP: " fmt #include <crypto/hash.h> +#include <crypto/utils.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/types.h> @@ -4899,7 +4900,7 @@ tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, else genhash = tp->af_specific->calc_md5_hash(newhash, key, NULL, skb); - if (genhash || memcmp(hash_location, newhash, 16) != 0) { + if (genhash || 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 75a11d7feb26..702fdff58f7a 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -87,6 +87,7 @@ #include <linux/skbuff_ref.h> #include <crypto/hash.h> +#include <crypto/utils.h> #include <linux/scatterlist.h> #include <trace/events/tcp.h> @@ -840,7 +841,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb, genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb); - if (genhash || memcmp(md5_hash_location, newhash, 16) != 0) + if (genhash || crypto_memneq(md5_hash_location, newhash, 16)) goto out; } diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 90afe81bc8e5..7f20db11e8ce 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -68,6 +68,7 @@ #include <linux/seq_file.h> #include <crypto/hash.h> +#include <crypto/utils.h> #include <linux/scatterlist.h> #include <trace/events/tcp.h> @@ -1089,7 +1090,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb, key.type = TCP_KEY_MD5; genhash = tcp_v6_md5_hash_skb(newhash, key.md5_key, NULL, skb); - if (genhash || memcmp(md5_hash_location, newhash, 16) != 0) + if (genhash || crypto_memneq(md5_hash_location, newhash, 16)) goto out; } #endif |