On Saturday 01 November 2008 03:14:05 Dax Kelson wrote:
On Sat, 2008-11-01 at 01:09 -0600, Dax Kelson wrote:
> On Wed, 2008-10-29 at 15:02 -0400, Steve Grubb wrote:
> > We tried to support this in F-10 by having a test run with ping. We
> > figured that is a simple well defined app that could be used as a test
> > subject. We opened bz 455713 to document the change over. Turns out
> > that people compile their own kernels and do not necessarily turn this
> > on. So, what do we do in that case?
>
> I thought more about this.
>
> How about a check in rc.sysinit to see if the kernel supports
> capabilities?
>
> If the check fails it could do either or both of the following:
>
> 1. Display and log nasty warning message
> 2. Run the command: chmod u+s `cat /etc/posixcapbinaries`
I don't like self modifying systems. It can generate audit events and cause
aide to complain.
> Doing 2. would be the "friendly" thing to give the
user a non-broken
> system. It does make it a bit more complicated because you'd want some
> logic that if they booted back to a kernel with posix capabilities you
> stripped the suid bits. Also, rpm verity will complain.
Another idea.
Leave all the binaries with SUID bit set, but have the /etc/fstab have
'nosuid' on all the filesystems.
The file system capabilities inside the kernel are treated as if they were
suid apps. IOW, nosuid also disables file system capabilities.
-Steve