linux-kernel - Re: [GIT PULL] kdbus for 4.1-rc1

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Message-ID: <20150421193852.GA12633@srcf.ucam.org>
Date:	Tue, 21 Apr 2015 20:38:53 +0100
From:	Matthew Garrett <mjg59@...f.ucam.org>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>
Cc:	Tom Gundersen <teg@...m.no>, Jiri Kosina <jkosina@...e.cz>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Andy Lutomirski <luto@...capital.net>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Arnd Bergmann <arnd@...db.de>,
	One Thousand Gnomes <gnomes@...rguk.ukuu.org.uk>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Daniel Mack <daniel@...que.org>,
	David Herrmann <dh.herrmann@...il.com>,
	Djalal Harouni <tixxdz@...ndz.org>
Subject: Re: [GIT PULL] kdbus for 4.1-rc1

On Tue, Apr 21, 2015 at 11:36:54AM -0500, Eric W. Biederman wrote:
> 
> HeHeHe.  You mean all I need to do to get around all of the logging servers is
> capture CAP_SYS_BOOT?  Say like just capture this crazy watchdog program
> that doesn't run as root so that it can only reboot the system? HeHeHe
> So I can just trigger a clean reboot wait for journald, auditd, and
> syslog all to shut down and then do evil things to the machine without
> having to worry about erasing forensic evidence?

CAP_SYS_BOOT gives you kexec, and kexec with init=/bin/sh lets you do 
anything. You added that in dc009d92435f99498cbc579ce76bf28e837e2c14 and 
now the horse is long gone. Don't give CAP_SYS_BOOT to anything you 
don't trust with full privileges.

-- 
Matthew Garrett | mjg59@...f.ucam.org
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