This is a note to let you know that I've just added the patch titled
dev_forward_skb: do not scrub skb mark within the same name space
to the 5.4-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:
dev_forward_skb-do-not-scrub-skb-mark-within-the-same-name-space.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ff70202b2d1ad522275c6aadc8c53519b6a22c57 Mon Sep 17 00:00:00 2001
From: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
Date: Thu, 24 Jun 2021 10:05:05 +0200
Subject: dev_forward_skb: do not scrub skb mark within the same name space
From: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
commit ff70202b2d1ad522275c6aadc8c53519b6a22c57 upstream.
The goal is to keep the mark during a bpf_redirect(), like it is done for
legacy encapsulation / decapsulation, when there is no x-netns.
This was initially done in commit 213dd74aee76 ("skbuff: Do not scrub skb
mark within the same name space").
When the call to skb_scrub_packet() was added in dev_forward_skb() (commit
8b27f27797ca ("skb: allow skb_scrub_packet() to be used by tunnels")), the
second argument (xnet) was set to true to force a call to skb_orphan(). At
this time, the mark was always cleanned up by skb_scrub_packet(), whatever
xnet value was.
This call to skb_orphan() was removed later in commit
9c4c325252c5 ("skbuff: preserve sock reference when scrubbing the skb.").
But this 'true' stayed here without any real reason.
Let's correctly set xnet in ____dev_forward_skb(), this function has access
to the previous interface and to the new interface.
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/linux/netdevice.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3763,7 +3763,7 @@ static __always_inline int ____dev_forwa
return NET_RX_DROP;
}
- skb_scrub_packet(skb, true);
+ skb_scrub_packet(skb, !net_eq(dev_net(dev), dev_net(skb->dev)));
skb->priority = 0;
return 0;
}
Patches currently in stable-queue which might be from nicolas.dichtel@xxxxxxxxx are
queue-5.4/dev_forward_skb-do-not-scrub-skb-mark-within-the-same-name-space.patch
