lkml.org 
[lkml]   [2022]   [Mar]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/6] property: add fwnode_property_read_string_index()
Le Fri, 18 Mar 2022 20:09:37 +0200,
Andy Shevchenko <andriy.shevchenko@linux.intel.com> a écrit :

> On Fri, Mar 18, 2022 at 05:49:12PM +0100, Clément Léger wrote:
> > Le Fri, 18 Mar 2022 18:26:00 +0200,
> > Andy Shevchenko <andriy.shevchenko@linux.intel.com> 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.
>
> I see, thanks for pointing out.
>
> Nevertheless, I don't like the idea of allocating memory in this case.
> Can we rather add a new callback that will provide us the necessary
> property directly?
>

IMHO, it would indeed be better. However,
fwnode_property_match_string() also allocates memory to do the same
kind of operation. Would you also like a callback for this one ?

Thanks,

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

\
 
 \ /
  Last update: 2022-03-21 08:54    [W:0.294 / U:0.184 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site