6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
[ Upstream commit c48ef9c4aed3632566b57ba66cec6ec78624d4cb ]
Since bhash2 was introduced, the example below does not work as expected.
These two bind() should conflict, but the 2nd bind() now succeeds.
from socket import *
s1 = socket(AF_INET6, SOCK_STREAM)
s1.bind(('::ffff:127.0.0.1', 0))
s2 = socket(AF_INET, SOCK_STREAM)
s2.bind(('127.0.0.1', s1.getsockname()[1]))
During the 2nd bind() in inet_csk_get_port(), inet_bind2_bucket_find()
fails to find the 1st socket's tb2, so inet_bind2_bucket_create() allocates
a new tb2 for the 2nd socket. Then, we call inet_csk_bind_conflict() that
checks conflicts in the new tb2 by inet_bhash2_conflict(). However, the
new tb2 does not include the 1st socket, thus the bind() finally succeeds.
In this case, inet_bind2_bucket_match() must check if AF_INET6 tb2 has
the conflicting v4-mapped-v6 address so that inet_bind2_bucket_find()
returns the 1st socket's tb2.
Note that if we bind two sockets to 127.0.0.1 and then ::FFFF:127.0.0.1,
the 2nd bind() fails properly for the same reason mentinoed in the previous
commit.
Fixes: 28044fc1d495 ("net: Add a bhash2 table hashed by port and address")
Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Acked-by: Andrei Vagin <avagin@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/ipv4/inet_hashtables.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index fb13a28577b01..ae5e786a0598d 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -800,8 +800,13 @@ static bool inet_bind2_bucket_match(const struct inet_bind2_bucket *tb,
return false;
#if IS_ENABLED(CONFIG_IPV6)
- if (sk->sk_family != tb->family)
+ if (sk->sk_family != tb->family) {
+ if (sk->sk_family == AF_INET)
+ return ipv6_addr_v4mapped(&tb->v6_rcv_saddr) &&
+ tb->v6_rcv_saddr.s6_addr32[3] == sk->sk_rcv_saddr;
+
return false;
+ }
if (sk->sk_family == AF_INET6)
return ipv6_addr_equal(&tb->v6_rcv_saddr, &sk->sk_v6_rcv_saddr);
--
2.40.1
