From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ivan Bulatovic , Casey Schaufler , Li Zefan , Tejun Heo Subject: [ 080/127] cgroup: initialize xattr before calling d_instantiate() Date: Wed, 5 Jun 2013 14:34:07 -0700 Message-Id: <20130605213227.041292220@linuxfoundation.org> In-Reply-To: <20130605213217.966891866@linuxfoundation.org> References: <20130605213217.966891866@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Li Zefan commit d6cbf35dac8a3dadb9103379820c96d7c85df3d9 upstream. cgroup_create_file() calls d_instantiate(), which may decide to look at the xattrs on the file. Smack always does this and SELinux can be configured to do so. But cgroup_add_file() didn't initialize xattrs before calling cgroup_create_file(), which finally leads to dereferencing NULL dentry->d_fsdata. This bug has been there since cgroup xattr was introduced. Reported-by: Ivan Bulatovic Reported-by: Casey Schaufler Signed-off-by: Li Zefan Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- kernel/cgroup.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2747,13 +2747,14 @@ static int cgroup_add_file(struct cgroup goto out; } + cfe->type = (void *)cft; + cfe->dentry = dentry; + dentry->d_fsdata = cfe; + simple_xattrs_init(&cfe->xattrs); + mode = cgroup_file_mode(cft); error = cgroup_create_file(dentry, mode | S_IFREG, cgrp->root->sb); if (!error) { - cfe->type = (void *)cft; - cfe->dentry = dentry; - dentry->d_fsdata = cfe; - simple_xattrs_init(&cfe->xattrs); list_add_tail(&cfe->node, &parent->files); cfe = NULL; }