From: Andi Kleen <ak@suse.de>
To: virtualization@lists.osdl.org
Subject: Re: [RFC PATCH 33/35] Add the Xenbus sysfs and virtual device hotplug driver.
Date: Tue, 9 May 2006 18:28:31 +0200
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Cc: Alexey Dobriyan <adobriyan@gmail.com>, Chris Wright <chrisw@sous-sol.org>,
       xen-devel@lists.xensource.com, linux-kernel@vger.kernel.org,
       Ian Pratt <ian.pratt@xensource.com>
References: <20060509084945.373541000@sous-sol.org> <20060509085200.826853000@sous-sol.org> <20060509160635.GB7237@mipter.zuzino.mipt.ru>
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On Tuesday 09 May 2006 18:06, Alexey Dobriyan wrote:
> > +/* Simplified asprintf. */
> > +char *kasprintf(const char *fmt, ...)
> > +{
> > +	va_list ap;
> > +	unsigned int len;
> > +	char *p, dummy[1];
> > +
> > +	va_start(ap, fmt);
> > +	/* FIXME: vsnprintf has a bug, NULL should work */
> > +	len = vsnprintf(dummy, 0, fmt, ap);
> > +	va_end(ap);
> > +
> > +	p = kmalloc(len + 1, GFP_KERNEL);
> > +	if (!p)
> > +		return NULL;
> > +	va_start(ap, fmt);
> > +	vsprintf(p, fmt, ap);
> > +	va_end(ap);
> > +	return p;
> > +}
> 
> This should go to lib/

First for kernel usage I think it should have a maximum length parameter
to avoid dumb code from being easily exploited.

And the bug should be fixed in vsnprintf instead of being worked
around.

-Andi
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