NuytsTech Security

CVE-2025-21810

by ·

In the Linux kernel, the following vulnerability has been resolved:

driver core: class: Fix wild pointer dereferences in API class_dev_iter_next()

There are a potential wild pointer dereferences issue regarding APIs
class_dev_iter_(init|next|exit)(), as explained by below typical usage:

// All members of @iter are wild pointers.
struct class_dev_iter iter;

// class_dev_iter_init(@iter, @class, …) checks parameter @class for
// potential class_to_subsys() error, and it returns void type and does
// not initialize its output parameter @iter, so caller can not detect
// the error and continues to invoke class_dev_iter_next(@iter) even if
// @iter still contains wild pointers.
class_dev_iter_init(&iter, …);

// Dereference these wild pointers in @iter here once suffer the error.
while (dev = class_dev_iter_next(&iter)) { … };

// Also dereference these wild pointers here.
class_dev_iter_exit(&iter);

Actually, all callers of these APIs have such usage pattern in kernel tree.
Fix by:
– Initialize output parameter @iter by memset() in class_dev_iter_init()
and give callers prompt by pr_crit() for the error.
– Check if @iter is valid in class_dev_iter_next().

More information : https://git.kernel.org/stable/c/1614e75d1a1b63db6421c7a4bf37004720c7376c

Tags: