From aa99e5f87bd54db55dd37cb130bd5eb55933027f Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Mon, 11 Sep 2023 11:36:56 -0700 Subject: tcp: Fix bind() regression for v4-mapped-v6 wildcard address. Andrei Vagin reported bind() regression with strace logs. If we bind() a TCPv6 socket to ::FFFF:0.0.0.0 and then bind() a TCPv4 socket to 127.0.0.1, the 2nd bind() should fail but now succeeds. from socket import * s1 = socket(AF_INET6, SOCK_STREAM) s1.bind(('::ffff:0.0.0.0', 0)) s2 = socket(AF_INET, SOCK_STREAM) s2.bind(('127.0.0.1', s1.getsockname()[1])) During the 2nd bind(), if tb->family is AF_INET6 and sk->sk_family is AF_INET in inet_bind2_bucket_match_addr_any(), we still need to check if tb has the v4-mapped-v6 wildcard address. The example above does not work after commit 5456262d2baa ("net: Fix incorrect address comparison when searching for a bind2 bucket"), but the blamed change is not the commit. Before the commit, the leading zeros of ::FFFF:0.0.0.0 were treated as 0.0.0.0, and the sequence above worked by chance. Technically, this case has been broken since bhash2 was introduced. Note that if we bind() two sockets to 127.0.0.1 and then ::FFFF:0.0.0.0, the 2nd bind() fails properly because we fall back to using bhash to detect conflicts for the v4-mapped-v6 address. Fixes: 28044fc1d495 ("net: Add a bhash2 table hashed by port and address") Reported-by: Andrei Vagin Closes: https://lore.kernel.org/netdev/ZPuYBOFC8zsK6r9T@google.com/ Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/inet_hashtables.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'net') diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index 5c54f2804174..a58b04052ca6 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -839,7 +839,8 @@ bool inet_bind2_bucket_match_addr_any(const struct inet_bind2_bucket *tb, const #if IS_ENABLED(CONFIG_IPV6) if (sk->sk_family != tb->family) { if (sk->sk_family == AF_INET) - return ipv6_addr_any(&tb->v6_rcv_saddr); + return ipv6_addr_any(&tb->v6_rcv_saddr) || + ipv6_addr_v4mapped_any(&tb->v6_rcv_saddr); return false; } -- cgit v1.2.3