This is a note to let you know that I've just added the patch titled
cgroup: initialize xattr before calling d_instantiate()
to the 3.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
cgroup-initialize-xattr-before-calling-d_instantiate.patch
and it can be found in the queue-3.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d6cbf35dac8a3dadb9103379820c96d7c85df3d9 Mon Sep 17 00:00:00 2001
From: Li Zefan <lizefan@xxxxxxxxxx>
Date: Tue, 14 May 2013 19:44:20 +0800
Subject: cgroup: initialize xattr before calling d_instantiate()
From: Li Zefan <lizefan@xxxxxxxxxx>
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@xxxxxxxxxxxx>
Reported-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
Signed-off-by: Li Zefan <lizefan@xxxxxxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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;
}
Patches currently in stable-queue which might be from lizefan@xxxxxxxxxx are
queue-3.9/cgroup-initialize-xattr-before-calling-d_instantiate.patch
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