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authorLi Zefan <lizefan@huawei.com>2013-05-14 19:44:20 +0800
committerTejun Heo <tj@kernel.org>2013-05-14 08:24:15 -0700
commitd6cbf35dac8a3dadb9103379820c96d7c85df3d9 (patch)
treebd25f2bebf2620ab87440e1e8b167e7bf3cdca20 /kernel/cgroup.c
parentf722406faae2d073cc1d01063d1123c35425939e (diff)
downloadlwn-d6cbf35dac8a3dadb9103379820c96d7c85df3d9.tar.gz
lwn-d6cbf35dac8a3dadb9103379820c96d7c85df3d9.zip
cgroup: initialize xattr before calling d_instantiate()
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. Cc: <stable@vger.kernel.org> # 3.8.x Reported-by: Ivan Bulatovic <combuster@archlinux.us> Reported-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/cgroup.c')
-rw-r--r--kernel/cgroup.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 2a9926275f80..38b136553044 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2699,13 +2699,14 @@ static int cgroup_add_file(struct cgroup *cgrp, struct cgroup_subsys *subsys,
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;
}