4.17-stable review patch. If anyone has any objections, please let me know.
------------------
From: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx>
Acked-by: John Fastabend <john.fastabend@xxxxxxxxx>
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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)
