From: Daniel Borkmann Date: Fri, 24 Aug 2018 20:08:51 +0000 (+0200) Subject: bpf, sockmap: fix psock refcount leak in bpf_tcp_recvmsg X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=15c480efab01197c965ce0562a43ffedd852b8f9;p=openwrt%2Fstaging%2Fblogic.git bpf, sockmap: fix psock refcount leak in bpf_tcp_recvmsg In bpf_tcp_recvmsg() we first took a reference on the psock, however once we find that there are skbs in the normal socket's receive queue we return with processing them through tcp_recvmsg(). Problem is that we leak the taken reference on the psock in that path. Given we don't really do anything with the psock at this point, move the skb_queue_empty() test before we fetch the psock to fix this case. Fixes: 8934ce2fd081 ("bpf: sockmap redirect ingress support") Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Signed-off-by: Alexei Starovoitov --- diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index 01879e4d599a..26d8a3053407 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -912,6 +912,8 @@ static int bpf_tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, if (unlikely(flags & MSG_ERRQUEUE)) return inet_recv_error(sk, msg, len, addr_len); + if (!skb_queue_empty(&sk->sk_receive_queue)) + return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len); rcu_read_lock(); psock = smap_psock_sk(sk); @@ -922,9 +924,6 @@ static int bpf_tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, goto out; rcu_read_unlock(); - if (!skb_queue_empty(&sk->sk_receive_queue)) - return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len); - lock_sock(sk); bytes_ready: while (copied != len) {