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From: Simon Horman <horms@verge.net.au>
To: "Dirk Müller" <dirk@dmllr.de>
Cc: kexec@lists.infradead.org
Subject: Re: [PATCH] Avoid buffer overflow on strncat usage
Date: Tue, 4 Feb 2014 21:37:12 +0900	[thread overview]
Message-ID: <20140204123712.GF17028@verge.net.au> (raw)
In-Reply-To: <CAL5wTH52b74cixBSfx84w5HH08hieo=pn8vGTnF_9x4GwMPv9w@mail.gmail.com>

On Tue, Feb 04, 2014 at 01:03:42PM +0100, Dirk Müller wrote:
> Hi Simon,
> 
> > I don't think you need the -1 as filename will have a trailing '\0'
> > which is not counted in the return value of strlen()
> 
> Thats true, but strncat always writes a trailing NUL, and to avoid
> that this one overflows the buffer, you need to subtract -1.
> 
> However, this code in particular can be rewrittten to use snprintf(),
> which avoids
> the overflow and is also a bit more readable.
> 
> How about the attached patch?

Looks good, I have applied it.


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      reply	other threads:[~2014-02-04 12:37 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-03 17:54 [PATCH] Avoid buffer overflow on strncat usage Dirk Müller
2014-02-04  8:30 ` Simon Horman
2014-02-04 12:03   ` Dirk Müller
2014-02-04 12:37     ` Simon Horman [this message]

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