| From | Kamal Mostafa <> | Subject | [PATCH 3.19.y-ckt 18/66] ipv4: l2tp: fix a potential issue in l2tp_ip_recv | Date | Tue, 26 Apr 2016 13:24:09 -0700 |
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3.19.8-ckt20 -stable review patch. If anyone has any objections, please let me know.
---8<------------------------------------------------------------
From: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
[ 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: Kamal Mostafa <kamal@canonical.com> --- net/l2tp/l2tp_ip.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c index 05dfc8a..cb24e2b 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); } -- 2.7.4
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