From 5121700b346b6160ccc9411194e3f1f417c340d1 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Wed, 8 Aug 2018 19:23:13 +0200 Subject: bpf, sockmap: fix bpf_tcp_sendmsg sock error handling While working on bpf_tcp_sendmsg() code, I noticed that when a sk->sk_err is set we error out with err = sk->sk_err. However this is problematic since sk->sk_err is a positive error value and therefore we will neither go into sk_stream_error() nor will we report an error back to user space. I had this case with EPIPE and user space was thinking sendmsg() succeeded since EPIPE is a positive value, thinking we submitted 32 bytes. Fix it by negating the sk->sk_err value. Fixes: 4f738adba30a ("bpf: create tcp_bpf_ulp allowing BPF to monitor socket TX/RX data") Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Signed-off-by: Alexei Starovoitov --- kernel/bpf/sockmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/bpf') diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index 98fb7938beea..f7360c4d7250 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -1053,7 +1053,7 @@ static int bpf_tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) int copy; if (sk->sk_err) { - err = sk->sk_err; + err = -sk->sk_err; goto out_err; } -- cgit v1.2.3 From 7c81c71730456845e6212dccbf00098faa66740f Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Wed, 8 Aug 2018 19:23:14 +0200 Subject: bpf, sockmap: fix leak in bpf_tcp_sendmsg wait for mem path 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 Signed-off-by: Alexei Starovoitov --- kernel/bpf/sockmap.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'kernel/bpf') diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index f7360c4d7250..c4d75c52b4fc 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 @@ wait_for_sndbuf: 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) -- cgit v1.2.3