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bpf, sockmap: fix leak in bpf_tcp_sendmsg wait for mem path

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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: 4f738adba3 ("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>
This commit is contained in:
Daniel Borkmann 2018-08-08 19:23:14 +02:00 committed by Alexei Starovoitov
parent 5121700b34
commit 7c81c71730
1 changed files with 5 additions and 2 deletions
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7
kernel/bpf/sockmap.c
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@ -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;
@ -1116,9 +1116,12 @@ 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)
err = sk_stream_error(sk, msg->msg_flags, err);