Re: [gentoo-user] User eix-sync permissions problem

[Mike Gilbert <floppym@gentoo.org>]

On Mon, Feb 10, 2014 at 8:23 PM, Walter Dnes <waltdnes@waltdnes.org> wrote:
> On Tue, Feb 11, 2014 at 12:28:43AM +0000, Kerin Millar wrote
>> On 10/02/2014 23:57, Walter Dnes wrote:
>> >
>> >    What's the point, if you still have to run as root (or su or sudo) for
>> > the emerge update process?
>>
>> It's the principle of least privilege. Is there any specific reason for
>> portage to fork and exec rsync as root? Is rsync sandboxed? Should rsync
>> have unfettered read/write access to all mounted filesystems? Can it be
>> guaranteed that rsync hasn't been compromised? Can it be guaranteed that
>> PORTAGE_RSYNC_OPTS will contain safe options at all times?
>>
>> The answer to all of these questions is "no". Basically, the combination
>> of usersync and non-root ownership of PORTDIR hardens the process in a
>> sensible way while conferring no disadvantage.
>
>   If /usr/portage is owned by portage:portage, then wouldn't a user
> (member of portage) be able to do mischief by tweaking ebuilds?  E.g.
> modify an ebuild to point to a tarball located on a usb stick, at
> http://127.0.0.1/media/sdc1/my_tarball.tgz.  This would allow a local
> user to supply code that gets built and then installed in /usr/bin, or
> /sbin, etc.
>

Don't add untrusted users to the portage group.