Re: One process with multiple user ids.

[Jan Engelhardt]

On Oct 2 2007 13:33, Giuliano Gagliardi wrote:

>Date: Tue, 2 Oct 2007 13:33:05 +0200
>From: Giuliano Gagliardi <gogi-k@xxxxxxx>
>To: Jan Engelhardt <jengelh@xxxxxxxxxxxxxxx>
>Subject: Re: One process with multiple user ids.
>
>On Tuesday 02 October 2007, Jan Engelhardt wrote:
>> On Oct 2 2007 12:56, Giuliano Gagliardi wrote:
>> >I have a server that has to switch to different user ids, but because it
>> > does other complex things, I would rather not have it run as root. I only
>> > need the server to be able to switch to certain pre-defined user ids.
>>
>> All you need is CAP_SETUID. Also see man setresuid,
>> where you could, I think, use saved_uid=0 if you do not
>> like to use real_uid=0 effective_uid=non-0.
>
>But CAP_SETUID would let me change to any uid, would it not? I would like my 
>process to have no possibility to change to any uid, except some predefined 
>set, so that in case of a security hole only those uids could be compromised.
>
>

You could write up a LSM that restricts UID changing.

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