From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mark H Weaver <mhw@netris.org>
Subject: Re: Can unprivileged users corrupt the store with bad tarballs?
Date: Fri, 04 Apr 2014 08:21:12 -0400
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In-Reply-To: <87eh1ep5id.fsf@gnu.org> ("Ludovic
	\=\?utf-8\?Q\?Court\=C3\=A8s\=22'\?\=
	\=\?utf-8\?Q\?s\?\= message of "Thu, 03 Apr 2014 21:39:06 +0200")
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To: Ludovic =?utf-8?Q?Court=C3=A8s?= <ludo@gnu.org>
Cc: guix-devel@gnu.org

ludo@gnu.org (Ludovic Court=C3=A8s) writes:

> Mark H Weaver <mhw@netris.org> skribis:
>
>> I was thinking about the security implications of giving out shell
>> access to one of my systems running Guix.
>>
>> When I ask guix-daemon to build package 'foo', it will use as an input
>> the source for package 'foo', usually a tarball.  If the tarball is
>> already in the store, it won't download it again, because it is
>> effectively cached in the store.
>>
>> It is possible for another user on the same system to corrupt the cache,
>> but manually adding a bad tarball for 'foo' to the store, in such a way
>> that it would be used to build 'foo' when I ask for it?
>
> No.
>
> Tarballs are fixed-output derivations, so the hash of the tarball is
> known in advance.  Thus, when building a package, you=E2=80=99re sure to =
use the
> tarball whose hash is in the recipe.

What about things that aren't fixed-output derivations?  Are the results
of 'origin' forms with included patches or snippets "fixed-output"?

Could an unprivileged user add one of these to the store that wasn't
authentic?

     Mark