Thread (33 messages) 33 messages, 3 authors, 2022-03-22

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

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Date: 2022-03-18 18:13:34
Also in: linux-acpi, linux-i2c, lkml

On Fri, Mar 18, 2022 at 05:49:12PM +0100, Clément Léger wrote:
Le Fri, 18 Mar 2022 18:26:00 +0200,
Andy Shevchenko [off-list ref] a écrit :
quoted
On Fri, Mar 18, 2022 at 05:00:47PM +0100, Clément Léger wrote:
quoted
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.  
...
quoted
quoted
+	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?

-- 
With Best Regards,
Andy Shevchenko

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