Re: [PATCH 1/6] property: add fwnode_property_read_string_index()

[Clément Léger]

Le Fri, 18 Mar 2022 18:26:00 +0200,
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> a écrit :

> On Fri, Mar 18, 2022 at 05:00:47PM +0100, Clément Léger wrote:
> > Add fwnode_property_read_string_index() function which allows to
> > retrieve a string from an array by its index. This function is the
> > equivalent of of_property_read_string_index() but for fwnode support.  
> 
> ...
> 
> > +	values = kcalloc(nval, sizeof(*values), GFP_KERNEL);
> > +	if (!values)
> > +		return -ENOMEM;
> > +
> > +	ret = fwnode_property_read_string_array(fwnode, propname, values, nval);
> > +	if (ret < 0)
> > +		goto out;
> > +
> > +	*string = values[index];
> > +out:
> > +	kfree(values);  
> 
> Here is UAF (use after free). How is it supposed to work?
> 

values is an array of pointers. I'm only retrieving a pointer out of
it.

-- 
Clément Léger,
Embedded Linux and Kernel engineer at Bootlin
https://bootlin.com