linux-kernel - Re: [PATCH v2] kernel: escape non-ASCII and control characters in printk()

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Date:	Sun, 3 Jul 2011 13:23:11 +0100
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	Vasiliy Kulikov <segoon@...nwall.com>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Ingo Molnar <mingo@...e.hu>,
	Andrew Morton <akpm@...ux-foundation.org>,
	James Morris <jmorris@...ei.org>,
	Namhyung Kim <namhyung@...il.com>,
	Greg Kroah-Hartman <gregkh@...e.de>,
	kernel-hardening@...ts.openwall.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] kernel: escape non-ASCII and control characters in
 printk()

> Also, the problem with CSI code is still here.  It cannot be filtered
> because it is a valid byte inside of UTF-8 character.  For a console
> with IUTF bit set all dangerous characters are filtered, but for the
> rest they are not.  As at the stage of vscnprintf the presence of IUTF
> bit is not clear, users of non-IUTF console should still use "| less" or
> similar.  Obviously, \n is filtered for all consoles.

This is why the filter pattern has to come from the console. Your patch
also for example doesn't fix anything on a 7bit serial console.. only the
hardware driver really knows what the filter rules are.

Looks a very good starting point though, and the embedded \n's mostly
want fixing up anyway.
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