This is a note to let you know that I've just added the patch titled
net: Fix potential wrong skb->protocol in skb_vlan_untag()
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-fix-potential-wrong-skb-protocol-in-skb_vlan_untag.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Wed Aug 26 04:28:25 PM CEST 2020
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Date: Sat, 15 Aug 2020 04:44:31 -0400
Subject: net: Fix potential wrong skb->protocol in skb_vlan_untag()
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
[ Upstream commit 55eff0eb7460c3d50716ed9eccf22257b046ca92 ]
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@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/core/skbuff.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -4370,8 +4370,8 @@ struct sk_buff *skb_vlan_untag(struct sk
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;
Patches currently in stable-queue which might be from linmiaohe@xxxxxxxxxx are
queue-4.4/net-fix-potential-wrong-skb-protocol-in-skb_vlan_untag.patch
