Re: Risk of local privilege escalation in GNU Guix

                							

                <!--X-Body-Begin-->
<!--X-User-Header-->

oss-sec
mailing list archives
<!--X-User-Header-End-->
<!--X-TopPNI-->

By Date

By Thread

</form>

<!--X-TopPNI-End-->
<!--X-MsgBody-->
<!--X-Subject-Header-Begin-->
Re: Risk of local privilege escalation in GNU Guix

<!--X-Subject-Header-End-->
<!--X-Head-of-Message-->

From: Leo Famulari &lt;leo () famulari name&gt;

Date: Sat, 10 Apr 2021 13:58:40 -0400

<!--X-Head-of-Message-End-->
<!--X-Head-Body-Sep-Begin-->

<!--X-Head-Body-Sep-End-->
<!--X-Body-of-Message-->
On Thu, Mar 18, 2021 at 05:27:09PM -0400, Leo Famulari wrote:
# Vulnerability

The attack consists in having an unprivileged user spawn a build process, for 
instance with `guix build`, that makes its build directory world-writable.  The 
user then creates a hardlink to a root-owned file such as `/etc/shadow` in that
build directory.  If the user passed the `--keep-failed` option and the build
eventually fails, the daemon changes ownership of the whole build tree,
including the hardlink, to the user.  At that point, the user has write access
to the target file.

This is CVE-2021-27851.

We are very grateful for the invaluable assistance of CERT/CC in getting
this assigned.
Attachment:
signature.asc
Description: 

<!--X-Body-of-Message-End-->
<!--X-MsgBody-End-->
<!--X-Follow-Ups-->

<!--X-Follow-Ups-End-->
<!--X-References-->
<!--X-References-End-->
<!--X-BotPNI-->

By Date

By Thread

Current thread:

Re: Risk of local privilege escalation in GNU Guix Leo Famulari (Apr 05)

Re: Risk of local privilege escalation in GNU Guix Henri Salo (Apr 05)

Re: Risk of local privilege escalation in GNU Guix Jan Engelhardt (Apr 05)

Re: Risk of local privilege escalation in GNU Guix Leo Famulari (Apr 05)

Re: Risk of local privilege escalation in GNU Guix Leo Famulari (Apr 05)

Re: Risk of local privilege escalation in GNU Guix Leo Famulari (Apr 09)

&lt;Possible follow-ups&gt;
Re: Risk of local privilege escalation in GNU Guix Leo Famulari (Apr 10)

 

<!--X-BotPNI-End-->
<!--X-User-Footer-->
<!--X-User-Footer-End-->