[added to the 3.18 stable tree] ipv6: l2tp: fix a potential issue in l2tp_ip6_recv
From: Sasha Levin <hidden>
Date: 2016-07-12 03:03:32
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Haishuang Yan <redacted> This patch has been added to the 3.18 stable tree. If you have any objections, please let us know. =============== [ Upstream commit be447f305494e019dfc37ea4cdf3b0e4200b4eba ] pskb_may_pull() can change skb->data, so we have to load ptr/optr at the right place. Signed-off-by: Haishuang Yan <redacted> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <redacted> --- net/l2tp/l2tp_ip6.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c
index 3865882..b8e469b 100644
--- a/net/l2tp/l2tp_ip6.c
+++ b/net/l2tp/l2tp_ip6.c@@ -135,12 +135,11 @@ 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;
@@ -168,6 +167,9 @@ 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); }
--
2.5.0