linux-kernel - Re: [PATCH -v3.1 2/2] printk: Add kernel parameter to control writes to /dev/kmsg

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Message-ID: <20160706183245.GJ7300@pd.tnic>
Date:	Wed, 6 Jul 2016 20:32:45 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Franck Bui <fbui@...e.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Ingo Molnar <mingo@...nel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>
Subject: Re: [PATCH -v3.1 2/2] printk: Add kernel parameter to control writes
 to /dev/kmsg

On Wed, Jul 06, 2016 at 01:52:11PM -0400, Steven Rostedt wrote:
> Hmm, this does nothing to stop user space from doing the following:
> 
> while :; do echo '5,0,0,-;hello' > /dev/kmsg; done

I wouldn't worry too much if /dev/kmsg has root:root perms elsewhere
too, like it is the case in my guest here:

crw-r--r-- 1 root root 1, 11 Jul  6 22:28 /dev/kmsg

root can shoot herself in the foot in countless ways anyway.

-- 
Regards/Gruss,
    Boris.

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