From: Kuniyuki Iwashima <kuniyu@amazon.com> mainline inclusion from mainline-v6.9-rc3 commit ea111449501ea32bf6da82750de860243691efc7 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/ICA4Z5 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- 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: Dong Chenchen <dongchenchen2@huawei.com> --- 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 2e253df378ae..177dac731fcd 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -199,8 +199,15 @@ 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); -- 2.25.1