of: Add a helper to free property struct

[ Upstream commit 1c5e3d9bf3 ]

Freeing a property struct is 3 kfree()'s which is duplicated in multiple
spots. Add a helper, __of_prop_free(), and replace all the open coded
cases in the DT code.

Reviewed-by: Saravana Kannan <saravanak@google.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20240409-dt-cleanup-free-v2-1-5b419a4af38d@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Stable-dep-of: 80af3745ca46 ("of: dynamic: Fix use after free in of_changeset_add_prop_helper()")
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/of/dynamic.c

@@ -306,15 +306,20 @@ int of_detach_node(struct device_node *np)
 }
 EXPORT_SYMBOL_GPL(of_detach_node);
 
+void __of_prop_free(struct property *prop)
+{
+	kfree(prop->name);
+	kfree(prop->value);
+	kfree(prop);
+}
+
 static void property_list_free(struct property *prop_list)
 {
 	struct property *prop, *next;
 
 	for (prop = prop_list; prop != NULL; prop = next) {
 		next = prop->next;
-		kfree(prop->name);
+		__of_prop_free(prop);
-		kfree(prop->value);
-		kfree(prop);
 	}
 }
 
@@ -427,9 +432,7 @@ struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
 	return new;
 
  err_free:
-	kfree(new->name);
+	__of_prop_free(new);
-	kfree(new->value);
-	kfree(new);
 	return NULL;
 }
 
@@ -471,9 +474,7 @@ struct device_node *__of_node_dup(const struct device_node *np,
 			if (!new_pp)
 				goto err_prop;
 			if (__of_add_property(node, new_pp)) {
-				kfree(new_pp->name);
+				__of_prop_free(new_pp);
-				kfree(new_pp->value);
-				kfree(new_pp);
 				goto err_prop;
 			}
 		}
@@ -933,11 +934,8 @@ static int of_changeset_add_prop_helper(struct of_changeset *ocs,
 		return -ENOMEM;
 
 	ret = of_changeset_add_property(ocs, np, new_pp);
-	if (ret) {
+	if (ret)
-		kfree(new_pp->name);
+		__of_prop_free(new_pp);
-		kfree(new_pp->value);
-		kfree(new_pp);
-	}
 
 	new_pp->next = np->deadprops;
 	np->deadprops = new_pp;

drivers/of/of_private.h

@@ -123,6 +123,7 @@ extern void *__unflatten_device_tree(const void *blob,
  * own the devtree lock or work on detached trees only.
  */
 struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags);
+void __of_prop_free(struct property *prop);
 struct device_node *__of_node_dup(const struct device_node *np,
 				  const char *full_name);
 

drivers/of/overlay.c

@@ -262,9 +262,7 @@ static struct property *dup_and_fixup_symbol_prop(
 	return new_prop;
 
 err_free_new_prop:
-	kfree(new_prop->name);
+	__of_prop_free(new_prop);
-	kfree(new_prop->value);
-	kfree(new_prop);
 err_free_target_path:
 	kfree(target_path);
 
@@ -361,11 +359,8 @@ static int add_changeset_property(struct overlay_changeset *ovcs,
 		pr_err("WARNING: memory leak will occur if overlay removed, property: %pOF/%s\n",
 		       target->np, new_prop->name);
 
-	if (ret) {
+	if (ret)
-		kfree(new_prop->name);
+		__of_prop_free(new_prop);
-		kfree(new_prop->value);
-		kfree(new_prop);
-	}
 	return ret;
 }
 

drivers/of/unittest.c

@@ -800,15 +800,11 @@ static void __init of_unittest_property_copy(void)
 
 	new = __of_prop_dup(&p1, GFP_KERNEL);
 	unittest(new && propcmp(&p1, new), "empty property didn't copy correctly\n");
-	kfree(new->value);
+	__of_prop_free(new);
-	kfree(new->name);
-	kfree(new);
 
 	new = __of_prop_dup(&p2, GFP_KERNEL);
 	unittest(new && propcmp(&p2, new), "non-empty property didn't copy correctly\n");
-	kfree(new->value);
+	__of_prop_free(new);
-	kfree(new->name);
-	kfree(new);
 #endif
 }
 
@@ -3665,9 +3661,7 @@ static __init void of_unittest_overlay_high_level(void)
 				goto err_unlock;
 			}
 			if (__of_add_property(of_symbols, new_prop)) {
-				kfree(new_prop->name);
+				__of_prop_free(new_prop);
-				kfree(new_prop->value);
-				kfree(new_prop);
 				/* "name" auto-generated by unflatten */
 				if (!strcmp(prop->name, "name"))
 					continue;