Re: CVE-2022-21499: trivial lockdown break

[John Haxby <john.haxby () oracle com>]

> 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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