drm: adv7511: Fix use-after-free in adv7533_attach_dsi()

The host_node pointer was assigned and freed in adv7533_parse_dt(), and
later, adv7533_attach_dsi() uses the same. Fix this use-after-free issue
by dropping of_node_put() in adv7533_parse_dt() and calling of_node_put()
in error path of probe() and also in the remove().

Fixes: 1e4d58c ("drm/bridge: adv7533: Create a MIPI DSI device")
Cc: [email protected]
Reviewed-by: Laurent Pinchart <[email protected]>
Signed-off-by: Biju Das <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Signed-off-by: Dmitry Baryshkov <[email protected]>

Author: bijudas

drivers/gpu/drm/bridge/adv7511/adv7511_drv.c

@@ -1241,8 +1241,10 @@ static int adv7511_probe(struct i2c_client *i2c)
 		return ret;
 
 	ret = adv7511_init_regulators(adv7511);
-	if (ret)
-		return dev_err_probe(dev, ret, "failed to init regulators\n");
+	if (ret) {
+		dev_err_probe(dev, ret, "failed to init regulators\n");
+		goto err_of_node_put;
+	}
 
 	/*
 	 * The power down GPIO is optional. If present, toggle it from active to
@@ -1363,6 +1365,8 @@ static int adv7511_probe(struct i2c_client *i2c)
 	i2c_unregister_device(adv7511->i2c_edid);
 uninit_regulators:
 	adv7511_uninit_regulators(adv7511);
+err_of_node_put:
+	of_node_put(adv7511->host_node);
 
 	return ret;
 }
@@ -1371,6 +1375,8 @@ static void adv7511_remove(struct i2c_client *i2c)
 {
 	struct adv7511 *adv7511 = i2c_get_clientdata(i2c);
 
+	of_node_put(adv7511->host_node);
+
 	adv7511_uninit_regulators(adv7511);
 
 	drm_bridge_remove(&adv7511->bridge);

drivers/gpu/drm/bridge/adv7511/adv7533.c

@@ -181,8 +181,6 @@ int adv7533_parse_dt(struct device_node *np, struct adv7511 *adv)
 	if (!adv->host_node)
 		return -ENODEV;
 
-	of_node_put(adv->host_node);
-
 	adv->use_timing_gen = !of_property_read_bool(np,
 						"adi,disable-timing-generator");