From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67730C4708E for ; Sat, 24 Dec 2022 01:43:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236956AbiLXBm4 (ORCPT ); Fri, 23 Dec 2022 20:42:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50600 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236980AbiLXBl0 (ORCPT ); Fri, 23 Dec 2022 20:41:26 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A2A056D53; Fri, 23 Dec 2022 17:33:31 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 44DB9B820E5; Sat, 24 Dec 2022 01:33:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5B13AC433EF; Sat, 24 Dec 2022 01:33:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1671845608; bh=EIgCMWs3Tz5uekwn3iU4tEYdtc23dIfLykia0lhVXxE=; h=From:To:Cc:Subject:Date:From; b=cbm3k12OAvAgKrD0zrZHJe49YXvEo+7DcOOkdRH/As5uPf5qsS7N6Y2itpXh4xjdM RsCvKgaPPYyjsjpKTq6DH3PUY3zEuFL4kD3T8dYNqtRAyn3ZGoJ9jeUOq/w9hkjQvj bOCt2qLG9RPbPJTPEAgP/fQYrV2VfVhGVx64tzJ1VPK8TCyXHmyPeeJtY8B/zjOzTg XQQ2FXsCngHRhORbNVLXC1EbmUT/mPsf4mZcI/4agM1YV/OfSCk/rFAEltZniORJBW CKwGxYSzgTyh2Hq65sZ8nfeoEs3eFkLb/28sHl3y01fR/XqwcJKQwKE2jFejWAoDfg nIbJEZMP2Vy9w== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Yang Yingliang , Luben Tuikov , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH AUTOSEL 4.9 1/4] kset: fix memory leak when kset_register() returns error Date: Fri, 23 Dec 2022 20:33:22 -0500 Message-Id: <20221224013325.393931-1-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Yang Yingliang [ Upstream commit 1662cea4623f75d8251adf07370bbaa958f0355d ] Inject fault while loading module, kset_register() may fail. If it fails, the kset.kobj.name allocated by kobject_set_name() which must be called before a call to kset_register() may be leaked, since refcount of kobj was set in kset_init(). To mitigate this, we free the name in kset_register() when an error is encountered, i.e. when kset_register() returns an error. A kset may be embedded in a larger structure which may be dynamically allocated in callers, it needs to be freed in ktype.release() or error path in callers, in this case, we can not call kset_put() in kset_register(), or it will cause double free, so just call kfree_const() to free the name and set it to NULL to avoid accessing bad pointer in callers. With this fix, the callers don't need care about freeing the name and may call kset_put() if kset_register() fails. Suggested-by: Luben Tuikov Signed-off-by: Yang Yingliang Reviewed-by: Link: https://lore.kernel.org/r/20221025071549.1280528-1-yangyingliang@huawei.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- lib/kobject.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/lib/kobject.c b/lib/kobject.c index bbbb067de8ec..be01d49abb62 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -806,6 +806,9 @@ EXPORT_SYMBOL_GPL(kobj_sysfs_ops); /** * kset_register - initialize and add a kset. * @k: kset. + * + * NOTE: On error, the kset.kobj.name allocated by() kobj_set_name() + * is freed, it can not be used any more. */ int kset_register(struct kset *k) { @@ -816,8 +819,12 @@ int kset_register(struct kset *k) kset_init(k); err = kobject_add_internal(&k->kobj); - if (err) + if (err) { + kfree_const(k->kobj.name); + /* Set it to NULL to avoid accessing bad pointer in callers. */ + k->kobj.name = NULL; return err; + } kobject_uevent(&k->kobj, KOBJ_ADD); return 0; } -- 2.35.1