diff options
| author | Eric Dumazet <edumazet@google.com> | 2022-07-26 11:57:43 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-07-27 10:18:21 -0700 |
| commit | e62d2e110356093c034998e093675df83057e511 (patch) | |
| tree | 1f814c250ba21d175b77c33f04156427a2ef22d1 /net/ipv4 | |
| parent | 5a159128faff151b7fe5f4eb0f310b1e0a2d56bf (diff) | |
tcp: md5: fix IPv4-mapped support
After the blamed commit, IPv4 SYN packets handled
by a dual stack IPv6 socket are dropped, even if
perfectly valid.
$ nstat | grep MD5
TcpExtTCPMD5Failure 5 0.0
For a dual stack listener, an incoming IPv4 SYN packet
would call tcp_inbound_md5_hash() with @family == AF_INET,
while tp->af_specific is pointing to tcp_sock_ipv6_specific.
Only later when an IPv4-mapped child is created, tp->af_specific
is changed to tcp_sock_ipv6_mapped_specific.
Fixes: 7bbb765b7349 ("net/tcp: Merge TCP-MD5 inbound callbacks")
Reported-by: Brian Vazquez <brianvv@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Dmitry Safonov <dima@arista.com>
Tested-by: Leonard Crestez <cdleonard@gmail.com>
Link: https://lore.kernel.org/r/20220726115743.2759832-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/tcp.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 002a4a04efbe..766881775abb 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4459,9 +4459,18 @@ tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, return SKB_DROP_REASON_TCP_MD5UNEXPECTED; } - /* check the signature */ - genhash = tp->af_specific->calc_md5_hash(newhash, hash_expected, - NULL, skb); + /* Check the signature. + * To support dual stack listeners, we need to handle + * IPv4-mapped case. + */ + if (family == AF_INET) + genhash = tcp_v4_md5_hash_skb(newhash, + hash_expected, + NULL, skb); + else + genhash = tp->af_specific->calc_md5_hash(newhash, + hash_expected, + NULL, skb); if (genhash || memcmp(hash_location, newhash, 16) != 0) { NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE); |