6.1-stable review patch. If anyone has any objections, please let me know.
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From: Kuniyuki Iwashima kuniyu@amazon.com
[ Upstream commit d91ef1e1b55f730bee8ce286b02b7bdccbc42973 ]
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@163.com Signed-off-by: Kuniyuki Iwashima kuniyu@amazon.com Link: https://lore.kernel.org/r/20240326204251.51301-3-kuniyu@amazon.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 f7832d4253820..8407098a59391 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -289,6 +289,7 @@ 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(); @@ -301,18 +302,20 @@ 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; }
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