Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 5745b823 authored by Haishuang Yan's avatar Haishuang Yan Committed by David S. Miller
Browse files

ipv4: l2tp: fix a potential issue in l2tp_ip_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 05cf8077

net/l2tp/l2tp_ip.c

+5 −3
Original line number Diff line number Diff line
@@ -123,12 +123,11 @@ static int l2tp_ip_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;
@@ -156,6 +155,9 @@ static int l2tp_ip_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);

	}