Dave Chinner <david <at> fromorbit.com> writes: > > 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 <at> oss.sgi.com > http://oss.sgi.com/mailman/listinfo/xfs > > I meet with a problem when using 64bit XFS and NFS, When I access a directory from the NFS client,I get Stale NFS file Handle error.But it is ok when accessing on the server without NFS. And I have checked that the inode num in the NFS file handle is the same as inode num on the server, Using ls -il. I found that XFS_IGET_UNTRUSTED in xfs_imap() filtered the function xfs_imap_lookup(),It fails in xfs_imap_lookup() when access from NFS client.local access does not go into xfs_imap_lookup(). My kernel is Linux2.6.35.6 from kernel.org. please help me to find out this problem! Thanks! _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
