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Commit b790c8ea authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Philipp Zabel
Browse files

reset: Fix potential use-after-free in __of_reset_control_get() 



Calling of_node_put() decreases the reference count of a device tree
object, and may free some data.

However, the of_phandle_args structure embedding it is passed to
reset_controller_dev.of_xlate() after that, so it may still be accessed.

Move the call to of_node_put() down to fix this.

Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
[p.zabel@pengutronix.de: moved of_node_put after mutex_unlock]
Signed-off-by: default avatarPhilipp Zabel <p.zabel@pengutronix.de>
parent eea2926b

drivers/reset/core.c

+8 −7
Original line number Diff line number Diff line
@@ -496,28 +496,29 @@ struct reset_control *__of_reset_control_get(struct device_node *node, 
			break;

		}

	}

	of_node_put(args.np);



	if (!rcdev) {

		mutex_unlock(&reset_list_mutex);

		return ERR_PTR(-EPROBE_DEFER);

		rstc = ERR_PTR(-EPROBE_DEFER);

		goto out;

	}



	if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) {

		mutex_unlock(&reset_list_mutex);

		return ERR_PTR(-EINVAL);

		rstc = ERR_PTR(-EINVAL);

		goto out;

	}



	rstc_id = rcdev->of_xlate(rcdev, &args);

	if (rstc_id < 0) {

		mutex_unlock(&reset_list_mutex);

		return ERR_PTR(rstc_id);

		rstc = ERR_PTR(rstc_id);

		goto out;

	}



	/* reset_list_mutex also protects the rcdev's reset_control list */

	rstc = __reset_control_get_internal(rcdev, rstc_id, shared);



out:

	mutex_unlock(&reset_list_mutex);

	of_node_put(args.np);



	return rstc;

}