path: root/net/ipv4/inet_hashtables.c
diff options
authorCraig Gallek <>2017-10-19 15:00:29 -0400
committerDavid S. Miller <>2017-10-22 02:03:51 +0100
commit1b5f962e71bfad6284574655c406597535c3ea7a (patch)
tree2f96c8a5f8251654c8aaf3874681cd04c02b24e8 /net/ipv4/inet_hashtables.c
parent66c54517540cedf5a22911c6b7f5c7d8b5d1e1be (diff)
soreuseport: fix initialization race
Syzkaller stumbled upon a way to trigger WARNING: CPU: 1 PID: 13881 at net/core/sock_reuseport.c:41 reuseport_alloc+0x306/0x3b0 net/core/sock_reuseport.c:39 There are two initialization paths for the sock_reuseport structure in a socket: Through the udp/tcp bind paths of SO_REUSEPORT sockets or through SO_ATTACH_REUSEPORT_[CE]BPF before bind. The existing implementation assumedthat the socket lock protected both of these paths when it actually only protects the SO_ATTACH_REUSEPORT path. Syzkaller triggered this double allocation by running these paths concurrently. This patch moves the check for double allocation into the reuseport_alloc function which is protected by a global spin lock. Fixes: e32ea7e74727 ("soreuseport: fast reuseport UDP socket selection") Fixes: c125e80b8868 ("soreuseport: fast reuseport TCP socket selection") Signed-off-by: Craig Gallek <> Signed-off-by: David S. Miller <>
Diffstat (limited to 'net/ipv4/inet_hashtables.c')
1 files changed, 1 insertions, 4 deletions
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 597bb4cfe805..e7d15fb0d94d 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -456,10 +456,7 @@ static int inet_reuseport_add_sock(struct sock *sk,
return reuseport_add_sock(sk, sk2);
- /* Initial allocation may have already happened via setsockopt */
- if (!rcu_access_pointer(sk->sk_reuseport_cb))
- return reuseport_alloc(sk);
- return 0;
+ return reuseport_alloc(sk);
int __inet_hash(struct sock *sk, struct sock *osk)