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Message-ID: <20240325181923.48769-2-kuniyu@amazon.com>
Date: Mon, 25 Mar 2024 11:19:16 -0700
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: "David S. Miller" <davem@...emloft.net>, Eric Dumazet
<edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni
<pabeni@...hat.com>, David Ahern <dsahern@...nel.org>
CC: Joanne Koong <joannelkoong@...il.com>, Jianguo Wu <wujianguo106@....com>,
Kuniyuki Iwashima <kuniyu@...zon.com>, Kuniyuki Iwashima
<kuni1840@...il.com>, <netdev@...r.kernel.org>
Subject: [PATCH v1 net 1/8] tcp: Fix bind() regression for v6-only wildcard and v4-mapped-v6 non-wildcard addresses.
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@...zon.com>
---
net/ipv4/inet_connection_sock.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 7d8090f109ef..612aa1d2eff7 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -203,7 +203,8 @@ 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))
+ if (ipv6_only_sock(sk2) &&
+ (sk->sk_family == AF_INET || ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr)))
return false;
return inet_bind_conflict(sk, sk2, sk_uid, relax,
--
2.30.2
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