Messages in this thread Patch in this message | | | Date | Wed, 11 Aug 2010 16:53:56 -0700 | From | Greg KH <> | Subject | [015/111] blkdev: cgroup whitelist permission fix |
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2.6.32-stable review patch. If anyone has any objections, please let us know.
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From: Chris Wright <chrisw@sous-sol.org>
commit b7300b78d1a87625975a799a109a2f98d77757c8 upstream.
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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/block_dev.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
--- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1175,10 +1175,12 @@ static int __blkdev_get(struct block_dev /* * 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();
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