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Date: Wed, 13 Feb 2019 20:56:48 +1100
From: Aleksa Sarai <cyphar@...har.com>
To: EJ Campbell <ejc3@...izonmedia.com>
Cc: oss-security@...ts.openwall.com
Subject: Re: CVE-2019-5736: runc container breakout exploit
 code

On 2019-02-13, EJ Campbell <ejc3@...izonmedia.com> wrote:
> While fixing docker / runc is clearly the right fix, would using chattr -i
> on runc be a quick mitigation for the issue? I believe that will prevent
> the file from being overwritten by the exploit and Etienne Stalmans
> verified that it helped:
>  https://twitter.com/_staaldraad/status/1095354945073754112

The privileged user in the container could just un-set the immutable
bit using "/proc/self/fd/..." and then open it for writing. A read-only
filesystem would work much better.

-- 
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
<https://www.cyphar.com/>

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