Re: [PATCH] Security: Add prctl(PR_{GET,SET}_NETWORK) interface.

Andi Kleen
2009-12-17T08:52:41Z

On Wed, Dec 16, 2009 at 08:25:40PM -0500, Michael Stone wrote:
> Andi Kleen wrote:
>> On Wed, Dec 16, 2009 at 10:32:43AM -0500, Michael Stone wrote:
>>> Daniel Bernstein has observed [1] that security-conscious userland processes
>>> may benefit from the ability to irrevocably remove their ability to create,
>>> bind, connect to, or send messages except in the case of previously
>>> connected sockets or AF_UNIX filesystem sockets. We provide this facility by
>>> implementing support for a new prctl(PR_SET_NETWORK) flag named
>>> PR_NETWORK_OFF.
>>>
>>> This facility is particularly attractive to security platforms like OLPC
>>> Bitfrost [2] and to isolation programs like Rainbow [3] and Plash [4].
>>
>> What would stop them from ptracing someone else running under the same
>> uid who still has the network access?
>
> Just like in the (revised from last year) rlimits version, there's a hunk in
> the prctl_network semantics patch which disables networking-via-ptrace() like
> so:

Hmm, ok. Missed that. I hope there are not more big holes. Obviously
can't allow to change other executables, but I guess that's ok.

It's still some overlap with network name spaces, but there are also
some not directly mappable semantic differences.

I haven't reviewed the patches in detail btw.

-Andi

--
ak@linux.intel.com -- Speaking for myself only.