From c48ef9c4aed3632566b57ba66cec6ec78624d4cb Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Mon, 11 Sep 2023 11:36:57 -0700 Subject: [PATCH] tcp: Fix bind() regression for v4-mapped-v6 non-wildcard address. Since bhash2 was introduced, the example below does not work as expected. These two bind() should conflict, but the 2nd bind() now succeeds. from socket import * s1 = socket(AF_INET6, SOCK_STREAM) s1.bind(('::ffff:127.0.0.1', 0)) s2 = socket(AF_INET, SOCK_STREAM) s2.bind(('127.0.0.1', s1.getsockname()[1])) During the 2nd bind() in inet_csk_get_port(), inet_bind2_bucket_find() fails to find the 1st socket's tb2, so inet_bind2_bucket_create() allocates a new tb2 for the 2nd socket. Then, we call inet_csk_bind_conflict() that checks conflicts in the new tb2 by inet_bhash2_conflict(). However, the new tb2 does not include the 1st socket, thus the bind() finally succeeds. In this case, inet_bind2_bucket_match() must check if AF_INET6 tb2 has the conflicting v4-mapped-v6 address so that inet_bind2_bucket_find() returns the 1st socket's tb2. Note that if we bind two sockets to 127.0.0.1 and then ::FFFF:127.0.0.1, the 2nd bind() fails properly for the same reason mentinoed in the previous commit. Fixes: 28044fc1d495 ("net: Add a bhash2 table hashed by port and address") Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Acked-by: Andrei Vagin Signed-off-by: David S. Miller --- net/ipv4/inet_hashtables.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index a58b04052ca6..c32f5e28758b 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -820,8 +820,13 @@ static bool inet_bind2_bucket_match(const struct inet_bind2_bucket *tb, return false; #if IS_ENABLED(CONFIG_IPV6) - if (sk->sk_family != tb->family) + if (sk->sk_family != tb->family) { + if (sk->sk_family == AF_INET) + return ipv6_addr_v4mapped(&tb->v6_rcv_saddr) && + tb->v6_rcv_saddr.s6_addr32[3] == sk->sk_rcv_saddr; + return false; + } if (sk->sk_family == AF_INET6) return ipv6_addr_equal(&tb->v6_rcv_saddr, &sk->sk_v6_rcv_saddr);