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Date: Sat, 4 Aug 2012 11:57:55 -0400
From: Dave Reisner <d@falconindy.com>
To: =?iso-8859-1?Q?P=E1draig?= Brady <P@draigBrady.com>
Cc: util-linux@vger.kernel.org
Subject: Re: suggestion to avoid erroneous lines in findmnt/lslocks/...
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References: <501D42D2.6050904@draigBrady.com>
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On Sat, Aug 04, 2012 at 04:42:10PM +0100, Pádraig Brady wrote:
> There was a recent change in df in coreutils to sanitize output of paths:
> 
> http://git.sv.gnu.org/gitweb/?p=coreutils.git;a=commitdiff;h=3ed70fd
> 
> The essential issue fixed there is that control chars in a path will be
> converted to '?' (this works in all locales), and doing so will mean
> '\n' for example is not output. You could even consider this a potential
> security improvement so that arbitrary users couldn't influence the
> output of these commands for all users.
> 
> I suggest using the simple inplace replacement function from above.

Why replace with a bogus character when you could instead use an octal
or hex escape? Wouldn't this still address the underlying problem?
Munging the content of a string could break a script consuming the
output with no way for the script to recover.