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 X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D5D1DC49EC8 for ; Mon, 28 Jun 2021 14:54:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B7A3961261 for ; Mon, 28 Jun 2021 14:54:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230394AbhF1O44 (ORCPT ); Mon, 28 Jun 2021 10:56:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:59764 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235865AbhF1OxD (ORCPT ); Mon, 28 Jun 2021 10:53:03 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 32A4B61D37; Mon, 28 Jun 2021 14:37:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1624891044; bh=HxIbMjLZ3pfTFH/OuSuLE3sjYWU92k1375vx+sIZZ6o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Mvh9qlMmKuelqzX/rjcUJ/KJVHCTsfrPLKVRfGv4nqMv0DrUodYwBo9jSlrQP9dLm w30U7u/2xOVc/mtGbXMteeht3l+22NOUO1Sf3jlQbKSPGqlrEb0dfbvY6+s6qUmhn6 cizRq/EJ0/+MCNji4xQWy5NbscLdt7768FjNBFmIyQ395ap74B9sROZaVRs5gWpXh8 CmPySHDYq8im0Jcx4E63+evKhS4aL2lJnz+utk4/BIjN+ZHcIa/BUpwAT6f50MR9HK CHx/93TqU56HQKZAOYWdEGzK3sOd0f5bRNUqMmXxOhOylkWEfJxxcoXL4n5p50HHPy Cjc/GawMLyUGw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Al Viro , "Guilherme G . Piccoli" , Greg Kroah-Hartman Subject: [PATCH 4.14 63/88] unfuck sysfs_mount() Date: Mon, 28 Jun 2021 10:36:03 -0400 Message-Id: <20210628143628.33342-64-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210628143628.33342-1-sashal@kernel.org> References: <20210628143628.33342-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.14.238-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-4.14.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 4.14.238-rc1 X-KernelTest-Deadline: 2021-06-30T14:36+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Al Viro commit 7b745a4e4051e1bbce40e0b1c2cf636c70583aa4 upstream. new_sb is left uninitialized in case of early failures in kernfs_mount_ns(), and while IS_ERR(root) is true in all such cases, using IS_ERR(root) || !new_sb is not a solution - IS_ERR(root) is true in some cases when new_sb is true. Make sure new_sb is initialized (and matches the reality) in all cases and fix the condition for dropping kobj reference - we want it done precisely in those situations where the reference has not been transferred into a new super_block instance. Signed-off-by: Al Viro Signed-off-by: Guilherme G. Piccoli Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/mount.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c index 20b8f82e115b..2bbe84d9c0a8 100644 --- a/fs/sysfs/mount.c +++ b/fs/sysfs/mount.c @@ -28,7 +28,7 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type, { struct dentry *root; void *ns; - bool new_sb; + bool new_sb = false; if (!(flags & MS_KERNMOUNT)) { if (!kobj_ns_current_may_mount(KOBJ_NS_TYPE_NET)) @@ -38,9 +38,9 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type, ns = kobj_ns_grab_current(KOBJ_NS_TYPE_NET); root = kernfs_mount_ns(fs_type, flags, sysfs_root, SYSFS_MAGIC, &new_sb, ns); - if (IS_ERR(root) || !new_sb) + if (!new_sb) kobj_ns_drop(KOBJ_NS_TYPE_NET, ns); - else if (new_sb) + else if (!IS_ERR(root)) root->d_sb->s_iflags |= SB_I_USERNS_VISIBLE; return root; -- 2.30.2