Re: CVE Request: powerdns does not clear supplementary groups

[Kurt Seifried <kseifried () redhat com>]

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On 05/24/2012 04:56 PM, Solar Designer wrote:
> On Thu, May 24, 2012 at 06:15:53PM -0400, Steve Grubb wrote:
> > Here is a real life case:
> >
> > + if ( initgroups(pw->pw_name, NULL) != 0 || setgid(pw->pw_gid)
> > != 0 || +                                setuid(pw->pw_uid) != 0
> > )
> >
> > This is not upstream. This is a patch to drop capabilities by
> > changing uid/gid. The person writing the patch intended to do the
> > right thing - but failed. See the bug? This is in a network
> > facing daemon that parses untrusted network packets.
>
> Wow.  The NULL results in group 0 being added to the supplementary 
> groups list (so it survives the setgid(), at least on my quick
> test).
>
> How did you spot this?  Compiler warning?
>
> "passing arg 2 of `initgroups' makes integer from pointer without a
> cast"
>
> Alexander

Ok this part I did not know, so this is an obvious trust boundary
violation (the intention was to drop privileges but it instead ADDS
root privileges).

Please use CVE-2012-2653 for this issue.

- -- 
Kurt Seifried Red Hat Security Response Team (SRT)
PGP: 0x5E267993 A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993

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