Re: getuid() vs. geteuid() in auditctl
On Wed, Mar 21, 2012 at 1:12 PM, Steve Grubb <sgrubb(a)redhat.com> wrote:
On Wednesday, March 21, 2012 12:38:06 PM Peter Moody wrote:
> On Tue, Mar 20, 2012 at 11:07 AM, Steve Grubb <sgrubb(a)redhat.com> wrote:
> > On Friday, March 16, 2012 05:50:56 PM Peter Moody wrote:
> >> line 1162 in auditctl.c has this:
> >>
> >> #ifndef DEBUG
> >> /* Make sure we are root */
> >> if (getuid() != 0) {
> >> fprintf(stderr, "You must be root to run this program.\n");
> >> return 4;
> >> }
> >> #endif
> >>
> >> Is there any particular reason to use getuid() there as opposed to
> >> geteuid()?
> >
> > I suppose it doesn't matter. I never envisioned having a helper
> > application, so that why its the way it is. Since we are optionally
> > linking in libcap-ng, I suppose we could even check the capability
> > rather than the euid.
>
> Just the CAP_AUDIT_CONTROL capability?
On the -m command, it instead needs CAP_AUDIT_WRITE.
Actually, is there any reason that check can't just be removed to
allow the kernel to reply with an error if an unprivileged/uncapable
user tries executing auditctl? requiring CAP_AUDIT_WRITE seems strange
if the user is just executing auditctl -h or auditctl -v (though those
are the only two commands I can see that a normal user should be able
to execute).
> > Also note that
> > for certification purposes the file permissions are restricted.
>
> The permissions of the auditctl binary?
Yes. We ship it 0750.
-Steve
--
Peter Moody Google 1.650.253.7306
Security Engineer pgp:0xC3410038