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authorHaishuang Yan <yanhaishuang@cmss.chinamobile.com>2016-04-03 22:09:24 +0800
committerDavid S. Miller <davem@davemloft.net>2016-04-04 16:00:28 -0400
commitbe447f305494e019dfc37ea4cdf3b0e4200b4eba (patch)
tree7bfc596ff99287a234d6c116d36aa66bc1ff4764 /net/l2tp
parent5745b8232e942abd5e16e85fa9b27cc21324acf0 (diff)
downloadlinux-be447f305494e019dfc37ea4cdf3b0e4200b4eba.tar.bz2
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: Haishuang Yan <yanhaishuang@cmss.chinamobile.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/l2tp')
-rw-r--r--net/l2tp/l2tp_ip6.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c
index 6b54ff3ff4cb..cd479903d943 100644
--- a/net/l2tp/l2tp_ip6.c
+++ b/net/l2tp/l2tp_ip6.c
@@ -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);
}