6.8-stable review patch. If anyone has any objections, please let me know.
------------------
From: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
commit d91ef1e1b55f730bee8ce286b02b7bdccbc42973 upstream.
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@xxxxxxx>
Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240326204251.51301-3-kuniyu@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/inet_connection_sock.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -294,6 +294,7 @@ static bool inet_bhash2_addr_any_conflic
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();
@@ -306,18 +307,20 @@ static bool inet_bhash2_addr_any_conflic
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;
-
- if (tb2 && inet_bhash2_conflict(sk, tb2, uid, relax, reuseport_cb_ok,
- reuseport_ok)) {
- spin_unlock(&head2->lock);
- return true;
+ inet_bind_bucket_for_each(tb2, &head2->chain) {
+ if (!inet_bind2_bucket_match_addr_any(tb2, net, port, l3mdev, sk))
+ continue;
+
+ 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;
}
/*
