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 066EFC4332F for ; Sat, 24 Dec 2022 01:40:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236739AbiLXBk3 (ORCPT ); Fri, 23 Dec 2022 20:40:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39636 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236928AbiLXBjB (ORCPT ); Fri, 23 Dec 2022 20:39:01 -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 E1ED253ECF; Fri, 23 Dec 2022 17:32:58 -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 8AC4FB821B2; Sat, 24 Dec 2022 01:32:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A5E08C4339B; Sat, 24 Dec 2022 01:32:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1671845577; bh=SW8CZoZBbTVkg3L2C6OmwKdnb1sVQlw8e/pGg1jmQ4A=; h=From:To:Cc:Subject:Date:From; b=lUrYD3IpN9qGmiUkZb6Mi2gyhq+Ek7xc+H4aqUQZN9dMLWzDsG3akDvwp1CC5kH9X p+L0DHgAvbhsRg79GN8F8Ise0TovWsCsxer5Mqr9KuHQGjxxWlv+KNBzMukxPgjgNX H3Qv81zt26IWf/wF+jwgRtGtOOFByHPYUgkcFBw7+zrYenxpuvHNwYtb8icmu4agHZ qHVW2cVgMkkEcKt3SzXNaU8sxAi/hpArl7l4izhBoJfn+l2zE7RHmFPyQ+rjpO2Amr fCR9X0AM+G51vvGL8KXfC5WB9ZDpYfeWw7fe/W1Y/QbLEcBxk+bbAb+sZNKbbASXzn SlwySsYDi3qLw== 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 4.19 1/6] kset: fix memory leak when kset_register() returns error Date: Fri, 23 Dec 2022 20:32:49 -0500 Message-Id: <20221224013254.393646-1-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 97d86dc17c42..1eb1230a2d28 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -821,6 +821,9 @@ 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) { @@ -831,8 +834,12 @@ 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