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From: Pavel Roskin <proski@gnu.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Junio C Hamano <junkio@cox.net>, git@vger.kernel.org
Subject: Re: [PATCH] off-by-one bugs found by valgrind
Date: Wed, 21 Dec 2005 16:47:21 -0500	[thread overview]
Message-ID: <1135201641.15567.7.camel@dv> (raw)
In-Reply-To: <43A9C654.2010009@zytor.com>

On Wed, 2005-12-21 at 13:17 -0800, H. Peter Anvin wrote:
> >>quote_c_style_counted() in quote.c uses a dangerous construct, when a
> >>variable is incremented once and used twice in the same expression.
> > 
> > Sorry, I do not follow you.  Isn't && a sequence point?

The patch is right, but my comment was wrong, sorry.

The actual problem detected by valgrind is that sp is dereferenced
before it's checked for the upper boundary.  So, if e.g. namelen is 6,
the code reads name[6] into ch and then leaves the loop.

> && is a sequence point.  The code is techically fine, but it's harder 
> than necessary to read.

That alone should be a good reason to apply this patch.

-- 
Regards,
Pavel Roskin

  reply	other threads:[~2005-12-21 21:47 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-12-21 20:35 [PATCH] off-by-one bugs found by valgrind Pavel Roskin
2005-12-21 20:59 ` Junio C Hamano
2005-12-21 21:17   ` H. Peter Anvin
2005-12-21 21:47     ` Pavel Roskin [this message]
2005-12-22  0:27   ` Horst von Brand

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