Commit be447f30 authored by Haishuang Yan's avatar Haishuang Yan Committed by David S. Miller
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ipv6: l2tp: fix a potential issue in l2tp_ip6_recv 



pskb_may_pull() can change skb->data, so we have to load ptr/optr at the
right place.

Signed-off-by: default avatarHaishuang Yan <yanhaishuang@cmss.chinamobile.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 5745b823

net/l2tp/l2tp_ip6.c

+5 −3
Original line number Diff line number Diff line
@@ -136,12 +136,11 @@ static int l2tp_ip6_recv(struct sk_buff *skb) 
	struct l2tp_tunnel *tunnel = NULL;

	int length;



	/* Point to L2TP header */

	optr = ptr = skb->data;



	if (!pskb_may_pull(skb, 4))

		goto discard;



	/* Point to L2TP header */

	optr = ptr = skb->data;

	session_id = ntohl(*((__be32 *) ptr));

	ptr += 4;
@@ -169,6 +168,9 @@ static int l2tp_ip6_recv(struct sk_buff *skb) 
		if (!pskb_may_pull(skb, length))

			goto discard;



		/* Point to L2TP header */

		optr = ptr = skb->data;

		ptr += 4;

		pr_debug("%s: ip recv\n", tunnel->name);

		print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);

	}