Re: Buffer overflows

From: Pierre Habouzit <madcoder@debian.org>
Date: Aug 30, 2007, 22:36 UTC
Message-ID: <20070830223616.GA29200@artemis.corp>
In-Reply-To: <7vtzqg7jrn.fsf@gitster.siamese.dyndns.org>

On Thu, Aug 30, 2007 at 10:14:04PM +0000, Junio C Hamano wrote:

Show 10 quoted lines

> "Reece Dunn" <msclrhd@googlemail.com> writes:
> 
> > Why is it easier? If you have a fixed-size buffer, why not use
> > strncpy, which is what a safe string API is essentially doing anyway?
> 
> I would not claim unchecked strcpy is good -- we obviously would
> want to fix them.
> 
> But at the same time use of strncpy, strlcpy and friends solves
> only half of the problem.

  Actually, strncpy solves nothing as it's completely broken in so many
ways: it does not necessarily ends the string with a NUL-char, and it
NUL-pads the buffer, making it really slow when you use it top copy 10
chars in a BUFSIZ-big buffer.

  strncpy should never ever be used, few programmers understand it, and
it's very error prone.

-- 
·O·  Pierre Habouzit
··O                                                madcoder@debian.org
OOO                                                http://www.madism.org