Re: [patch 1/2] c/r: prctl: Add ability to set newmm_struct::exe_file

[Cyrill Gorcunov]

On Mon, Mar 19, 2012 at 03:46:49PM -0700, Andrew Morton wrote:
> 
> Please send a patch with the updated changelog and improved comment?

Sure I'll resend.

> 
> > >
> > > Actually I liked multi-shot version more but Matt arguments convinced
> > > me that one-short fashion is more "secure" in terms of overall kernel
> > > state and potential transitions/changes of this /proc/pid/exe symlink.
> > >
> > > At least with one-shot version the admin may be sure that the symlink
> > > is never changed more than once, ever.
> > >
> > 
> > And changing it once does not harm security?
> > I'm sure that rootkit writers will like this feature...
> 
> Well, let's discuss this more completely.  In what ways could an
> attacker use this?  How serious is the problem?  What actions can be
> taken to lessen it?  etcetera.

It can use it iif CAP_SYS_RESOURCE is granted.
Otherwise you'll get -eaccess.

	Cyrill
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