2016-04-03 14:09:41

by Haishuang Yan

Subject: [PATCH 1/2] 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: Haishuang Yan <[email protected]>
---
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 ec22078..42de4cc 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);
}
--
1.8.3.1

2016-04-03 14:09:34

by Haishuang Yan

Subject: [PATCH 2/2] 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 <[email protected]>
---
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 6b54ff3..cd47990 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);
}
--
1.8.3.1

2016-04-04 20:01:17

by David Miller

Subject: Re: [PATCH 1/2] ipv4: l2tp: fix a potential issue in l2tp_ip_recv

From: Haishuang Yan <[email protected]>
Date: Sun, 3 Apr 2016 22:09:23 +0800

> pskb_may_pull() can change skb->data, so we have to load ptr/optr at the
> right place.
>
> Signed-off-by: Haishuang Yan <[email protected]>

Applied and queued up for -stable.

2016-04-04 20:01:24

by David Miller

Subject: Re: [PATCH 2/2] ipv6: l2tp: fix a potential issue in l2tp_ip6_recv

From: Haishuang Yan <[email protected]>
Date: Sun, 3 Apr 2016 22:09:24 +0800

> pskb_may_pull() can change skb->data, so we have to load ptr/optr at the
> right place.
>
> Signed-off-by: Haishuang Yan <[email protected]>

Applied and queued up for -stable.