Re: [PATCH 4.19] xfrm: policy: match with both mark and mask on user interfaces

[Greg KH <greg@kroah.com>]

On Tue, Apr 12, 2022 at 09:33:58AM +0200, Tobias Brunner wrote:
> From: Xin Long <lucien.xin@gmail.com>
> 
> commit 4f47e8ab6ab796b5380f74866fa5287aca4dcc58 upstream.
> 
> In commit ed17b8d377ea ("xfrm: fix a warning in xfrm_policy_insert_list"),
> it would take 'priority' to make a policy unique, and allow duplicated
> policies with different 'priority' to be added, which is not expected
> by userland, as Tobias reported in strongswan.
> 
> To fix this duplicated policies issue, and also fix the issue in
> commit ed17b8d377ea ("xfrm: fix a warning in xfrm_policy_insert_list"),
> when doing add/del/get/update on user interfaces, this patch is to change
> to look up a policy with both mark and mask by doing:
> 
>   mark.v == pol->mark.v && mark.m == pol->mark.m
> 
> and leave the check:
> 
>   (mark & pol->mark.m) == pol->mark.v
> 
> for tx/rx path only.
> 
> As the userland expects an exact mark and mask match to manage policies.
> 
> v1->v2:
>   - make xfrm_policy_mark_match inline and fix the changelog as
>     Tobias suggested.
> 
> Cc: <stable@vger.kernel.org> # 4.19.x
> Fixes: 295fae568885 ("xfrm: Allow user space manipulation of SPD mark")
> Fixes: ed17b8d377ea ("xfrm: fix a warning in xfrm_policy_insert_list")
> Reported-by: Tobias Brunner <tobias@strongswan.org>
> Tested-by: Tobias Brunner <tobias@strongswan.org>
> Signed-off-by: Xin Long <lucien.xin@gmail.com>
> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
> ---
> This is a backport to 4.19.x of a fix that has already been applied
> to newer stable kernels.  However, due to conflicts it was never
> included in the 4.x trees, which all contain backports of the
> problematic commit referenced above (ed17b8d377ea).  So they all are
> prone to creating duplicate IPsec policies with priority updates.

All 3 now queued up, thanks.

greg k-h