Re: [PATCH] fix dst_entry leak in icmp_push_reply()

[Patrick McHardy <kaber@trash.net>]

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Ollie Wild wrote:
> That said, I appreciate that the if-else condition doesn't seem quite
> right.  The problem is, the icmp_push_reply() routine is implicitly
> using the queue as a success indicator.  I put the
> ip_flush_pending_frames() call inside the else block because I wanted to
> guarantee that one of ip_push_pending_frames() and
> ip_flush_pending_frames() is always called.  Both will do proper cleanup.
> 
> I'm open to suggestions if you think there's a cleaner way to implement
> this.

Checking the return value of ip_append_data seems cleaner to me.
Patch attached.

Signed-off-by: Patrick McHardy <kaber@trash.net>

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diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -349,12 +349,12 @@ static void icmp_push_reply(struct icmp_
 {
 	struct sk_buff *skb;
 
-	ip_append_data(icmp_socket->sk, icmp_glue_bits, icmp_param,
-		       icmp_param->data_len+icmp_param->head_len,
-		       icmp_param->head_len,
-		       ipc, rt, MSG_DONTWAIT);
-
-	if ((skb = skb_peek(&icmp_socket->sk->sk_write_queue)) != NULL) {
+	if (ip_append_data(icmp_socket->sk, icmp_glue_bits, icmp_param,
+		           icmp_param->data_len+icmp_param->head_len,
+		           icmp_param->head_len,
+		           ipc, rt, MSG_DONTWAIT) < 0)
+		ip_flush_pending_frames(icmp_socket->sk);
+	else if ((skb = skb_peek(&icmp_socket->sk->sk_write_queue)) != NULL) {
 		struct icmphdr *icmph = skb->h.icmph;
 		unsigned int csum = 0;
 		struct sk_buff *skb1;