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authorChris Wright <chrisw@sous-sol.org>2010-08-10 18:02:55 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2010-08-13 13:30:51 -0700
commiteff3960f25026fbeb854303535974491a5afba13 (patch)
treed2fea2f0bf53c80b53638501ecc3729a7775cf56
parent752638f5e4285a42b2df0394c060054f7154c85e (diff)
downloadlinux-2.6.34-ux500-eff3960f25026fbeb854303535974491a5afba13.tar.gz
blkdev: cgroup whitelist permission fix
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>
-rw-r--r--fs/block_dev.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c
index b3171fb0dc9..4c54c86e028 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1339,10 +1339,12 @@ 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();