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Date: Wed, 8 Aug 2018 19:23:14 +0200
From: Daniel Borkmann <daniel@...earbox.net>
To: netdev@...r.kernel.org
Cc: ast@...nel.org, john.fastabend@...il.com,
Daniel Borkmann <daniel@...earbox.net>
Subject: [PATCH bpf 2/3] 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 <daniel@...earbox.net>
Acked-by: John Fastabend <john.fastabend@...il.com>
---
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
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