6.8-stable review patch. If anyone has any objections, please let me know.
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From: Kuniyuki Iwashima kuniyu@amazon.com
commit ea111449501ea32bf6da82750de860243691efc7 upstream.
Commit 5e07e672412b ("tcp: Use bhash2 for v4-mapped-v6 non-wildcard address.") introduced bind() regression for v4-mapped-v6 address.
When we bind() the following two addresses on the same port, the 2nd bind() should succeed but fails now.
1. [::] w/ IPV6_ONLY 2. ::ffff:127.0.0.1
After the chagne, v4-mapped-v6 uses bhash2 instead of bhash to detect conflict faster, but I forgot to add a necessary change.
During the 2nd bind(), inet_bind2_bucket_match_addr_any() returns the tb2 bucket of [::], and inet_bhash2_conflict() finally calls inet_bind_conflict(), which returns true, meaning conflict.
inet_bhash2_addr_any_conflict |- inet_bind2_bucket_match_addr_any <-- return [::] bucket `- inet_bhash2_conflict `- __inet_bhash2_conflict <-- checks IPV6_ONLY for AF_INET | but not for v4-mapped-v6 address `- inet_bind_conflict <-- does not check address
inet_bind_conflict() does not check socket addresses because __inet_bhash2_conflict() is expected to do so.
However, it checks IPV6_V6ONLY attribute only against AF_INET socket, and not for v4-mapped-v6 address.
As a result, v4-mapped-v6 address conflicts with v6-only wildcard address.
To avoid that, let's add the missing test to use bhash2 for v4-mapped-v6 address.
Fixes: 5e07e672412b ("tcp: Use bhash2 for v4-mapped-v6 non-wildcard address.") Signed-off-by: Kuniyuki Iwashima kuniyu@amazon.com Link: https://lore.kernel.org/r/20240326204251.51301-2-kuniyu@amazon.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/inet_connection_sock.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index c038e28e2f1e..4184d45f890c 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -203,8 +203,15 @@ static bool __inet_bhash2_conflict(const struct sock *sk, struct sock *sk2, kuid_t sk_uid, bool relax, bool reuseport_cb_ok, bool reuseport_ok) { - if (sk->sk_family == AF_INET && ipv6_only_sock(sk2)) - return false; + if (ipv6_only_sock(sk2)) { + if (sk->sk_family == AF_INET) + return false; + +#if IS_ENABLED(CONFIG_IPV6) + if (ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr)) + return false; +#endif + }
return inet_bind_conflict(sk, sk2, sk_uid, relax, reuseport_cb_ok, reuseport_ok);