diff options
| author | Haishuang Yan <yanhaishuang@cmss.chinamobile.com> | 2016-04-03 22:09:23 +0800 |
|---|---|---|
| committer | Dmitry Shmidt <dimitrysh@google.com> | 2016-04-20 16:21:10 -0700 |
| commit | d31243b121a7d66d58a2180b5c4a83118f289471 (patch) | |
| tree | d18472965f64ab6021e401d73256598794dd5d66 | |
| parent | a1ae5f174d91a41214a4b2d0188c873701ed7d59 (diff) | |
ipv4: l2tp: fix a potential issue in l2tp_ip_recv
[ Upstream commit 5745b8232e942abd5e16e85fa9b27cc21324acf0 ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/l2tp/l2tp_ip.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c index ec22078b0914..42de4ccd159f 100644 --- a/net/l2tp/l2tp_ip.c +++ b/net/l2tp/l2tp_ip.c @@ -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); } |