This series closes a recently discovered problem in XFS filehandle conversion. On systems where inodes are dynamically deleted, XFS does not adequately verify the inode numbers in the filehandles, which results in reading stale inodes from disk and potentially returning them as valid files. Because these unlinked inodes were never zeroed out when the chunk was deallocated, some inodes in the chunk can still appear to have to data extents attached to them. This can lead to stale data exposure, exposure of active data and potentially overwriting of active data if the stale extents referenced in the unlinked inodes have been re-allocated. Both NFS filehandles and local filehandles provided through libhandle have this same problem. libhandle requires root permissions to use the interface, so it is not exposing information that you can't get more easily with other means (e.g. xfs_db or reading directly form the block device), so there isn't really an issue here. For NFS, we may incorrectly accept stale file handles for unlinked inodes after a server reboot if the unlinked inodes have not been overwritten leading to the above issues being triggered if multiple NFS clients are accessing the some files. Christoph's make-bulkstat-coherent patch is the basis for this series as bulkstat can also expose unlinked inodes and information about them back to userspace because it makes the same assumptions about inode lookups as the file handle interfaces. As a result, the first two patches of the series make up the real bug fix. The last two patches make it clear we are looking up untrusted inode numbers and remove a shortcut that these interfaces used that we do not want used any more. Hence for backports to other kernels, only the first two patches are necessary. More information and the test program that demonstrates the issue via the open_by_handle interface can be found here: http://oss.sgi.com/archives/xfs/2010-06/msg00191.html _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
