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| author | Li Zefan <lizefan@huawei.com> | 2013-05-14 19:44:20 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-06-07 12:53:05 -0700 |
| commit | 24622f8bb1d75e005f6cd1ccaea82b72e31b6d6c (patch) | |
| tree | 39dc535b002650b3c959e15a219cc6c494d44d98 | |
| parent | 52f36be0f4e2fafa5dd85fbd6508bbfba314fd58 (diff) | |
| download | lwn-24622f8bb1d75e005f6cd1ccaea82b72e31b6d6c.tar.gz lwn-24622f8bb1d75e005f6cd1ccaea82b72e31b6d6c.zip | |
cgroup: initialize xattr before calling d_instantiate()
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 <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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/cgroup.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index ba1f9776dd10..95e08e30c176 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2747,13 +2747,14 @@ 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; } |