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

[David Miller]

From: Haishuang Yan 
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 

Applied and queued up for -stable.

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

[David Miller]

From: Haishuang Yan 
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 

Applied and queued up for -stable.

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

[Haishuang Yan]

pskb_may_pull() can change skb->data, so we have to load ptr/optr at the
right place.

Signed-off-by: Haishuang Yan 
---
 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

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

[Haishuang Yan]

pskb_may_pull() can change skb->data, so we have to load ptr/optr at the
right place.

Signed-off-by: Haishuang Yan 
---
 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