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| author | Chris Wright <chrisw@sous-sol.org> | 2010-08-10 18:02:55 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-08-11 08:59:18 -0700 |
| commit | b7300b78d1a87625975a799a109a2f98d77757c8 (patch) | |
| tree | 8cf263c09daf725ee701b0acd7ad700c530a5f08 /fs/block_dev.c | |
| parent | e400c28524af2d344b1663b27bf28984fa959a0e (diff) | |
| download | lwn-b7300b78d1a87625975a799a109a2f98d77757c8.tar.gz lwn-b7300b78d1a87625975a799a109a2f98d77757c8.zip | |
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.
Basically, the only ways to reliably allow a cgroup access to a partition
on a block device when using the whitelist are to 1) also give it access
to the whole block device or 2) make sure the partition is already open in
a different context.
The patch avoids the cgroup check for the whole disk case when opening a
partition.
Addresses https://bugzilla.redhat.com/show_bug.cgi?id=589662
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Tested-by: Serge E. Hallyn <serue@us.ibm.com>
Reported-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "Daniel P. Berrange" <berrange@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/block_dev.c')
| -rw-r--r-- | 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 66411463b734..50e8c8582faa 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1340,10 +1340,12 @@ 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; + } } restart: |