Subject: Re: [syzbot] UBSAN: shift-out-of-bounds in tcf_pedit_init

From: Jakub Kicinski <[email-masked]>
Date: Thu, 12 May 2022 15:51:36 -0700

On Thu, 12 May 2022 14:19:51 -0700 Eric Dumazet wrote:
> On Thu, May 12, 2022 at 2:18 PM syzbot
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> As mentioned earlier, this came with
> 
> commit 8b796475fd7882663a870456466a4fb315cc1bd6
> Author: Paolo Abeni <[email-masked]>
> Date:   Tue May 10 16:57:34 2022 +0200
> 
>     net/sched: act_pedit: really ensure the skb is writable

Came in as in new stack trace for an old/existing bug, right?
Nothing checks the shift so it'd have already tripped UBSAN 
later on in tcf_pedit_act(), anyway.