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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 CD612C43381 for ; Fri, 22 Mar 2019 12:03:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9DEC821A4A for ; Fri, 22 Mar 2019 12:03:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553256206; bh=UJ2ahH+WU3dxFLgJ1mQZA3nDylyzrYmxPX5KT0Apu3o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=OjO7VxUPQuzmISOTQESMJBEdxdmRgtxrYRzHjABR8K3T5KEDU1xZ8qzHtM6mfpll3 CWQJf74lOB2ad6XyzR1lbTE4PmbQAhjbFw1WZL2o+lDGie+ZrTb+RwUvUMrokQOhI8 kHHScVpAfRJOM7fJj8W25Gx7DZGXo3NhDHGfigCM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388016AbfCVMDZ (ORCPT ); Fri, 22 Mar 2019 08:03:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:41722 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388043AbfCVMDX (ORCPT ); Fri, 22 Mar 2019 08:03:23 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D13D5204FD; Fri, 22 Mar 2019 12:03:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553256202; bh=UJ2ahH+WU3dxFLgJ1mQZA3nDylyzrYmxPX5KT0Apu3o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RBPJ/JZhvxIg5upGSbIOWu0Tcf20v6zORYjJlizq57n17exl5Uzuaz6RBN/SYeNbG l/o2Rl8xgbXZzhj147XouKV/bAhPZjybNkDNrSBcEvNXfxYnEMPz6lvjnorBAhV0ap mEVmrFYeyfApj7v/AnQwR1rH1+lEC+ZPeoF9wr5s= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, stable@kernel.org, Al Viro Subject: [PATCH 4.19 121/280] fix cgroup_do_mount() handling of failure exits Date: Fri, 22 Mar 2019 12:14:34 +0100 Message-Id: <20190322111315.074443430@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190322111306.356185024@linuxfoundation.org> References: <20190322111306.356185024@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Al Viro commit 399504e21a10be16dd1408ba0147367d9d82a10c upstream. same story as with last May fixes in sysfs (7b745a4e4051 "unfuck sysfs_mount()"); new_sb is left uninitialized in case of early errors in kernfs_mount_ns() and papering over it by treating any error from kernfs_mount_ns() as equivalent to !new_ns ends up conflating the cases when objects had never been transferred to a superblock with ones when that has happened and resulting new superblock had been dropped. Easily fixed (same way as in sysfs case). Additionally, there's a superblock leak on kernfs_node_dentry() failure *and* a dentry leak inside kernfs_node_dentry() itself - the latter on probably impossible errors, but the former not impossible to trigger (as the matter of fact, injecting allocation failures at that point *does* trigger it). Cc: stable@kernel.org Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman --- fs/kernfs/mount.c | 8 ++++++-- kernel/cgroup/cgroup.c | 9 ++++++--- 2 files changed, 12 insertions(+), 5 deletions(-) --- a/fs/kernfs/mount.c +++ b/fs/kernfs/mount.c @@ -196,8 +196,10 @@ struct dentry *kernfs_node_dentry(struct return dentry; knparent = find_next_ancestor(kn, NULL); - if (WARN_ON(!knparent)) + if (WARN_ON(!knparent)) { + dput(dentry); return ERR_PTR(-EINVAL); + } do { struct dentry *dtmp; @@ -206,8 +208,10 @@ struct dentry *kernfs_node_dentry(struct if (kn == knparent) return dentry; kntmp = find_next_ancestor(kn, knparent); - if (WARN_ON(!kntmp)) + if (WARN_ON(!kntmp)) { + dput(dentry); return ERR_PTR(-EINVAL); + } dtmp = lookup_one_len_unlocked(kntmp->name, dentry, strlen(kntmp->name)); dput(dentry); --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -1998,7 +1998,7 @@ struct dentry *cgroup_do_mount(struct fi struct cgroup_namespace *ns) { struct dentry *dentry; - bool new_sb; + bool new_sb = false; dentry = kernfs_mount(fs_type, flags, root->kf_root, magic, &new_sb); @@ -2008,6 +2008,7 @@ struct dentry *cgroup_do_mount(struct fi */ if (!IS_ERR(dentry) && ns != &init_cgroup_ns) { struct dentry *nsdentry; + struct super_block *sb = dentry->d_sb; struct cgroup *cgrp; mutex_lock(&cgroup_mutex); @@ -2018,12 +2019,14 @@ struct dentry *cgroup_do_mount(struct fi spin_unlock_irq(&css_set_lock); mutex_unlock(&cgroup_mutex); - nsdentry = kernfs_node_dentry(cgrp->kn, dentry->d_sb); + nsdentry = kernfs_node_dentry(cgrp->kn, sb); dput(dentry); + if (IS_ERR(nsdentry)) + deactivate_locked_super(sb); dentry = nsdentry; } - if (IS_ERR(dentry) || !new_sb) + if (!new_sb) cgroup_put(&root->cgrp); return dentry;