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Message-ID: <20240325181923.48769-3-kuniyu@amazon.com>
Date: Mon, 25 Mar 2024 11:19:17 -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 2/8] tcp: Fix bind() regression for v6-only wildcard and v4(-mapped-v6) non-wildcard addresses.
Jianguo Wu reported another bind() regression introduced by bhash2.
Calling bind() for the following 3 addresses on the same port, the
3rd one should fail but now succeeds.
1. 0.0.0.0 or ::ffff:0.0.0.0
2. [::] w/ IPV6_V6ONLY
3. IPv4 non-wildcard address or v4-mapped-v6 non-wildcard address
The first two bind() create tb2 like this:
bhash2 -> tb2(:: w/ IPV6_V6ONLY) -> tb2(0.0.0.0)
The 3rd bind() will match with the IPv6 only wildcard address bucket
in inet_bind2_bucket_match_addr_any(), however, no conflicting socket
exists in the bucket. So, inet_bhash2_conflict() will returns false,
and thus, inet_bhash2_addr_any_conflict() returns false consequently.
As a result, the 3rd bind() bypasses conflict check, which should be
done against the IPv4 wildcard address bucket.
So, in inet_bhash2_addr_any_conflict(), we must iterate over all buckets.
Note that we cannot add ipv6_only flag for inet_bind2_bucket as it
would confuse the following patetrn.
1. [::] w/ SO_REUSE{ADDR,PORT} and IPV6_V6ONLY
2. [::] w/ SO_REUSE{ADDR,PORT}
3. IPv4 non-wildcard address or v4-mapped-v6 non-wildcard address
The first bind() would create a bucket with ipv6_only flag true,
the second bind() would add the [::] socket into the same bucket,
and the third bind() could succeed based on the wrong assumption
that ipv6_only bucket would not conflict with v4(-mapped-v6) address.
Fixes: 28044fc1d495 ("net: Add a bhash2 table hashed by port and address")
Diagnosed-by: Jianguo Wu <wujianguo106@....com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
---
net/ipv4/inet_connection_sock.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 612aa1d2eff7..63e8f2df0681 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -288,6 +288,7 @@ static bool inet_bhash2_addr_any_conflict(const struct sock *sk, int port, int l
struct sock_reuseport *reuseport_cb;
struct inet_bind_hashbucket *head2;
struct inet_bind2_bucket *tb2;
+ bool conflict = false;
bool reuseport_cb_ok;
rcu_read_lock();
@@ -300,18 +301,20 @@ static bool inet_bhash2_addr_any_conflict(const struct sock *sk, int port, int l
spin_lock(&head2->lock);
- inet_bind_bucket_for_each(tb2, &head2->chain)
- if (inet_bind2_bucket_match_addr_any(tb2, net, port, l3mdev, sk))
- break;
+ inet_bind_bucket_for_each(tb2, &head2->chain) {
+ if (!inet_bind2_bucket_match_addr_any(tb2, net, port, l3mdev, sk))
+ continue;
- if (tb2 && inet_bhash2_conflict(sk, tb2, uid, relax, reuseport_cb_ok,
- reuseport_ok)) {
- spin_unlock(&head2->lock);
- return true;
+ if (!inet_bhash2_conflict(sk, tb2, uid, relax, reuseport_cb_ok, reuseport_ok))
+ continue;
+
+ conflict = true;
+ break;
}
spin_unlock(&head2->lock);
- return false;
+
+ return conflict;
}
/*
--
2.30.2
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