netdev - [PATCH v2 net 1/8] tcp: Fix bind() regression for v6-only wildcard and v4-mapped-v6 non-wildcard addresses.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240326204251.51301-2-kuniyu@amazon.com>
Date: Tue, 26 Mar 2024 13:42:44 -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 v2 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 | 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 7d8090f109ef..c365fe9dbacd 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);
-- 
2.30.2