2010-06-04 20:15:56

by Chris Wright

Subject: [PATCH] blkdev: cgroup whitelist permission fix

The cgroup device whitelist code gets confused when trying to grant
permission to a disk partition that is not currently open. Part of
blkdev_open() includes __blkdev_get() on the whole disk. This simply
avoids the cgroup check for the whole disk case when opening a
partition.

https://bugzilla.redhat.com/show_bug.cgi?id=589662

Acked-by: Serge E. Hallyn <[email protected]>
Tested-by: Serge E. Hallyn <[email protected]>
Signed-off-by: Chris Wright <[email protected]>
---
fs/block_dev.c | 10 ++++++----
1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 7346c96..09b107e 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1315,10 +1315,12 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
/*
* hooks: /n/, see "layering violations".
*/
- ret = devcgroup_inode_permission(bdev->bd_inode, perm);
- if (ret != 0) {
- bdput(bdev);
- return ret;
+ if (!for_part) {
+ ret = devcgroup_inode_permission(bdev->bd_inode, perm);
+ if (ret != 0) {
+ bdput(bdev);
+ return ret;
+ }
}

lock_kernel();

2010-07-15 15:55:28

by Chris Wright

Subject: Re: [PATCH] blkdev: cgroup whitelist permission fix

* Chris Wright ([email protected]) wrote:
> The cgroup device whitelist code gets confused when trying to grant
> permission to a disk partition that is not currently open. Part of
> blkdev_open() includes __blkdev_get() on the whole disk. This simply
> avoids the cgroup check for the whole disk case when opening a
> partition.
>
> https://bugzilla.redhat.com/show_bug.cgi?id=589662
>
> Acked-by: Serge E. Hallyn <[email protected]>
> Tested-by: Serge E. Hallyn <[email protected]>
> Signed-off-by: Chris Wright <[email protected]>

Andrew, plans to push this on? Christoph doesn't like the whole of
blockdev whitelisting for good reason, but it's currently in use and
has this bug.

thanks,
-chris