diff mbox series

net: Fix potential wrong skb->protocol in skb_vlan_untag()

Message ID 20200815084431.16813-1-linmiaohe@huawei.com
State New
Headers show
Series net: Fix potential wrong skb->protocol in skb_vlan_untag() | expand

Commit Message

Miaohe Lin Aug. 15, 2020, 8:44 a.m. UTC 
We may access the two bytes after vlan_hdr in vlan_set_encap_proto(). So
we should pull VLAN_HLEN + sizeof(unsigned short) in skb_vlan_untag() or
we may access the wrong data.

Fixes: 0d5501c1c828 ("net: Always untag vlan-tagged traffic on input.")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
 net/core/skbuff.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 7e2e502ef519..5c3b906aeef3 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5418,8 +5418,8 @@  struct sk_buff *skb_vlan_untag(struct sk_buff *skb)
 	skb = skb_share_check(skb, GFP_ATOMIC);
 	if (unlikely(!skb))
 		goto err_free;
-
-	if (unlikely(!pskb_may_pull(skb, VLAN_HLEN)))
+	/* We may access the two bytes after vlan_hdr in vlan_set_encap_proto(). */
+	if (unlikely(!pskb_may_pull(skb, VLAN_HLEN + sizeof(unsigned short))))
 		goto err_free;
 
 	vhdr = (struct vlan_hdr *)skb->data;