linux-kernel - [PATCH v1 1/2] driver core: class: Clear private pointer on registration failures

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4463268.LvFx2qVVIh@kreacher>
Date:   Fri, 20 Jan 2023 20:46:57 +0100
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Linux PM <linux-pm@...r.kernel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Zhang Rui <rui.zhang@...el.com>
Subject: [PATCH v1 1/2] driver core: class: Clear private pointer on registration failures

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Clear the class private pointer if __class_register() fails for it, so
as to allow its users to verify that the class is usable by checking
the value of that pointer.

For consistency, clear that pointer before freeing the object pointed
to by it in class_release().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/base/class.c |   16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

Index: linux-pm/drivers/base/class.c
===================================================================
--- linux-pm.orig/drivers/base/class.c
+++ linux-pm/drivers/base/class.c
@@ -53,6 +53,8 @@ static void class_release(struct kobject
 
 	pr_debug("class '%s': release.\n", class->name);
 
+	class->p = NULL;
+
 	if (class->class_release)
 		class->class_release(class);
 	else
@@ -186,17 +188,21 @@ int __class_register(struct class *cls,
 	cls->p = cp;
 
 	error = kset_register(&cp->subsys);
-	if (error) {
-		kfree(cp);
-		return error;
-	}
+	if (error)
+		goto err_out;
+
 	error = class_add_groups(class_get(cls), cls->class_groups);
 	class_put(cls);
 	if (error) {
 		kobject_del(&cp->subsys.kobj);
 		kfree_const(cp->subsys.kobj.name);
-		kfree(cp);
+		goto err_out;
 	}
+	return 0;
+
+err_out:
+	kfree(cp);
+	cls->p = NULL;
 	return error;
 }
 EXPORT_SYMBOL_GPL(__class_register);