4.18-stable review patch. If anyone has any objections, please let me know.
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From: Daniel Borkmann daniel@iogearbox.net
[ Upstream commit 15c480efab01197c965ce0562a43ffedd852b8f9 ]
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 daniel@iogearbox.net Acked-by: John Fastabend john.fastabend@gmail.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/bpf/sockmap.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
--- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -915,6 +915,8 @@ static int bpf_tcp_recvmsg(struct sock *
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); @@ -925,9 +927,6 @@ static int bpf_tcp_recvmsg(struct sock * 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) {