From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Borkmann Subject: [PATCH bpf 2/3] bpf, sockmap: fix leak in bpf_tcp_sendmsg wait for mem path Date: Wed, 8 Aug 2018 19:23:14 +0200 Message-ID: <20180808172315.4710-3-daniel@iogearbox.net> References: <20180808172315.4710-1-daniel@iogearbox.net> Cc: ast@kernel.org, john.fastabend@gmail.com, Daniel Borkmann To: netdev@vger.kernel.org Return-path: Received: from www62.your-server.de ([213.133.104.62]:42643 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727472AbeHHToC (ORCPT ); Wed, 8 Aug 2018 15:44:02 -0400 In-Reply-To: <20180808172315.4710-1-daniel@iogearbox.net> Sender: netdev-owner@vger.kernel.org List-ID: In bpf_tcp_sendmsg() the sk_alloc_sg() may fail. In the case of ENOMEM, it may also mean that we've partially filled the scatterlist entries with pages. Later jumping to sk_stream_wait_memory() we could further fail with an error for several reasons, however we miss to call free_start_sg() if the local sk_msg_buff was used. Fixes: 4f738adba30a ("bpf: create tcp_bpf_ulp allowing BPF to monitor socket TX/RX data") Signed-off-by: Daniel Borkmann Acked-by: John Fastabend --- kernel/bpf/sockmap.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index f7360c4..c4d75c5 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -1048,7 +1048,7 @@ static int bpf_tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); while (msg_data_left(msg)) { - struct sk_msg_buff *m; + struct sk_msg_buff *m = NULL; bool enospc = false; int copy; @@ -1116,8 +1116,11 @@ static int bpf_tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); wait_for_memory: err = sk_stream_wait_memory(sk, &timeo); - if (err) + if (err) { + if (m && m != psock->cork) + free_start_sg(sk, m); goto out_err; + } } out_err: if (err < 0) -- 2.9.5