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List:       oss-security
Subject:    Re: [oss-security] CVE-2022-21499: trivial lockdown break
From:       John Haxby <john.haxby () oracle ! com>
Date:       2022-05-24 20:18:02
Message-ID: D57406DE-02FB-43BD-BE4D-27A8ECA2C517 () oracle ! com
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> On 24 May 2022, at 18:10, John Haxby <john.haxby@oracle.com> wrote:
> 
> Hello All,
> 
> CVE-2022-21499: trivial lockdown break
> 
> We recently discovered that it is trivial to break lockdown (and secureboot) using the kernel \
> debugger: you can use the debugger to write zero into a location of your choice ... 
> I originally posted this with a preliminary patch on linux-distros.   Since then we have \
> developed a better patch that takes into account the differences between integrity and \
> confidentiality modes. 
> The updated patch will be available in the Linux mainline kernel at almost the same time as \
> I'm sending this email.  I'll reply with the commit ID as soon as I have it.   If anyone \
> wants the simpler patch that I posted to linux-bistros, please let me know, but I would \
> encourage you to take the full patch. 
> jch


The commit that fixes this is eadb2f47a3ce ("lockdown: also lock down previous kgdb use") [1]

jch


[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=eadb2f47a3ced5c64b23b90fd2a3463f63726066



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