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authorEric Dumazet <edumazet@google.com>2022-07-26 11:57:43 +0000
committerJakub Kicinski <kuba@kernel.org>2022-07-27 10:18:21 -0700
commite62d2e110356093c034998e093675df83057e511 (patch)
tree1f814c250ba21d175b77c33f04156427a2ef22d1 /net
parent5a159128faff151b7fe5f4eb0f310b1e0a2d56bf (diff)
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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')
-rw-r--r--net/ipv4/tcp.c15
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);