[Xen-devel] Re: [RFC PATCH 33/35] Add the Xenbus sysfs and virtual device hotplug driver.

[Andi Kleen <ak@xxxxxxx>]

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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