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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 23 Jun 2011 14:44:21 -0700
From:	Greg KH <gregkh@...e.de>
To:	Matthew Garrett <mjg59@...f.ucam.org>
Cc:	Vasiliy Kulikov <segoon@...nwall.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	James Morris <jmorris@...ei.org>, Ingo Molnar <mingo@...e.hu>,
	Namhyung Kim <namhyung@...il.com>,
	kernel-hardening@...ts.openwall.com, linux-kernel@...r.kernel.org,
	security@...nel.org
Subject: Re: [PATCH] kernel: escape non-ASCII and control characters in
 printk()

On Thu, Jun 23, 2011 at 02:36:05PM +0100, Matthew Garrett wrote:
> On Wed, Jun 22, 2011 at 08:37:42AM -0700, Greg KH wrote:
> > On Wed, Jun 22, 2011 at 01:53:41PM +0400, Vasiliy Kulikov wrote:
> > > This patch escapes all characters outside of allowed '\n' plus 0x20-0x7E
> > > charset passed to printk().
> > > 
> > > There are numerous printk() instances with user supplied input as "%s"
> > > data, and unprivileged user may craft log messages with substrings
> > > containing control characters via these printk()s.  Control characters
> > > might fool root viewing the logs via tty.
> > 
> > There are "numerous" places this could happen?
> 
> USB product identifiers?

That's one, sure, but the ability to overwrite something else that you
don't want someone to see based on plugging in a USB device is pretty
slim.  If I can plug any type of USB device I want into the system, odds
are I just owned it anyway...

greg k-h
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/