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authorMiaohe Lin <linmiaohe@huawei.com>2020-08-15 10:44:31 +0200
committerDavid S. Miller <davem@davemloft.net>2020-08-17 00:33:49 +0200
commit55eff0eb7460c3d50716ed9eccf22257b046ca92 (patch)
treec75b285de0dca2367dbe68eee0252ea49ed24eb7 /net
parentnet: xdp: pull ethernet header off packet after computing skb->protocol (diff)
downloadlinux-55eff0eb7460c3d50716ed9eccf22257b046ca92.tar.xz
linux-55eff0eb7460c3d50716ed9eccf22257b046ca92.zip
net: Fix potential wrong skb->protocol in skb_vlan_untag()
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> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/skbuff.c4
1 files changed, 2 insertions, 2 deletions
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;