4.17-stable review patch. If anyone has any objections, please let me know.
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From: Daniel Borkmann daniel@iogearbox.net
commit 7c81c71730456845e6212dccbf00098faa66740f upstream.
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 daniel@iogearbox.net Acked-by: John Fastabend john.fastabend@gmail.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/bpf/sockmap.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -947,7 +947,7 @@ static int bpf_tcp_sendmsg(struct sock * 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;
@@ -1015,8 +1015,11 @@ 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)