net: fix a race in sock_queue_err_skb()
As soon as an skb is queued into socket error queue, another thread
can consume it, so we are not allowed to reference skb anymore, or risk
use after free.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index f223cdc..baf8d28 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3161,6 +3161,8 @@
*/
int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
{
+ int len = skb->len;
+
if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
(unsigned)sk->sk_rcvbuf)
return -ENOMEM;
@@ -3175,7 +3177,7 @@
skb_queue_tail(&sk->sk_error_queue, skb);
if (!sock_flag(sk, SOCK_DEAD))
- sk->sk_data_ready(sk, skb->len);
+ sk->sk_data_ready(sk, len);
return 0;
}
EXPORT_SYMBOL(sock_queue_err_skb);