litmus-rt-imx6.git/fs/xfs, branch master

xfs: underflow bug in xfs_attrlist_by_handle()

2013-12-20T15:45:08+00:00

commit 31978b5cc66b8ba8a7e8eef60b12395d41b7b890 upstream.

If we allocate less than sizeof(struct attrlist) then we end up
corrupting memory or doing a ZERO_PTR_SIZE dereference.

This can only be triggered with CAP_SYS_ADMIN.

Reported-by: Nico Golde 
Reported-by: Fabian Yamaguchi 
Signed-off-by: Dan Carpenter 
Reviewed-by: Dave Chinner 
Signed-off-by: Ben Myers 
Signed-off-by: Greg Kroah-Hartman

xfs: growfs overruns AGFL buffer on V4 filesystems

2013-12-20T15:45:08+00:00

commit f94c44573e7c22860e2c3dfe349c45f72ba35ad3 upstream.

This loop in xfs_growfs_data_private() is incorrect for V4
superblocks filesystems:

		for (bucket = 0; bucket < XFS_AGFL_SIZE(mp); bucket++)
			agfl->agfl_bno[bucket] = cpu_to_be32(NULLAGBLOCK);

For V4 filesystems, we don't have a agfl header structure, and so
XFS_AGFL_SIZE() returns an entire sector's worth of entries, which
we then index from an offset into the sector. Hence: buffer overrun.

This problem was introduced in 3.10 by commit 77c95bba ("xfs: add
CRC checks to the AGFL") which changed the AGFL structure but failed
to update the growfs code to handle the different structures.

Fix it by using the correct offset into the buffer for both V4 and
V5 filesystems.

Signed-off-by: Dave Chinner 
Reviewed-by: Jie Liu 
Signed-off-by: Ben Myers 
Signed-off-by: Greg Kroah-Hartman

xfs: add capability check to free eofblocks ioctl

2013-12-08T15:29:27+00:00

commit 8c567a7fab6e086a0284eee2db82348521e7120c upstream.

Check for CAP_SYS_ADMIN since the caller can truncate preallocated
blocks from files they do not own nor have write access to. A more
fine grained access check was considered: require the caller to
specify their own uid/gid and to use inode_permission to check for
write, but this would not catch the case of an inode not reachable
via path traversal from the callers mount namespace.

Add check for read-only filesystem to free eofblocks ioctl.

Reviewed-by: Brian Foster 
Reviewed-by: Dave Chinner 
Reviewed-by: Gao feng 
Signed-off-by: Dwight Engen 
Signed-off-by: Ben Myers 
Cc: Kees Cook 
Signed-off-by: Greg Kroah-Hartman

xfs: fix node forward in xfs_node_toosmall

2013-10-13T23:08:34+00:00

commit 997def25e4b9cee3b01609e18a52f926bca8bd2b upstream.

Commit f5ea1100 cleans up the disk to host conversions for
node directory entries, but because a variable is reused in
xfs_node_toosmall() the next node is not correctly found.
If the original node is small enough (<= 3/8 of the node size),
this change may incorrectly cause a node collapse when it should
not. That will cause an assert in xfstest generic/319:

   Assertion failed: first <= last && last < BBTOB(bp->b_length),
   file: /root/newest/xfs/fs/xfs/xfs_trans_buf.c, line: 569

Keep the original node header to get the correct forward node.

(When a node is considered for a merge with a sibling, it overwrites the
 sibling pointers of the original incore nodehdr with the sibling's
 pointers.  This leads to loop considering the original node as a merge
 candidate with itself in the second pass, and so it incorrectly
 determines a merge should occur.)

[v3: added Dave Chinner's (slightly modified) suggestion to the commit header,
	cleaned up whitespace.  -bpm]

Signed-off-by: Mark Tinguely 
Reviewed-by: Ben Myers 
Signed-off-by: Ben Myers 
Signed-off-by: Greg Kroah-Hartman

xfs: don't shutdown log recovery on validation errors

2013-06-14T20:59:45+00:00

Unfortunately, we cannot guarantee that items logged multiple times
and replayed by log recovery do not take objects back in time. When
they are taken back in time, the go into an intermediate state which
is corrupt, and hence verification that occurs on this intermediate
state causes log recovery to abort with a corruption shutdown.

Instead of causing a shutdown and unmountable filesystem, don't
verify post-recovery items before they are written to disk. This is
less than optimal, but there is no way to detect this issue for
non-CRC filesystems If log recovery successfully completes, this
will be undone and the object will be consistent by subsequent
transactions that are replayed, so in most cases we don't need to
take drastic action.

For CRC enabled filesystems, leave the verifiers in place - we need
to call them to recalculate the CRCs on the objects anyway. This
recovery problem can be solved for such filesystems - we have a LSN
stamped in all metadata at writeback time that we can to determine
whether the item should be replayed or not. This is a separate piece
of work, so is not addressed by this patch.

Signed-off-by: Dave Chinner 
Reviewed-by: Ben Myers 
Signed-off-by: Ben Myers 

(cherry picked from commit 9222a9cf86c0d64ffbedf567412b55da18763aa3)

xfs: ensure btree root split sets blkno correctly

2013-06-14T20:59:31+00:00

For CRC enabled filesystems, the BMBT is rooted in an inode, so it
passes through a different code path on root splits than the
freespace and inode btrees. This is much less traversed by xfstests
than the other trees. When testing on a 1k block size filesystem,
I've been seeing ASSERT failures in generic/234 like:

XFS: Assertion failed: cur->bc_btnum != XFS_BTNUM_BMAP || cur->bc_private.b.allocated == 0, file: fs/xfs/xfs_btree.c, line: 317

which are generally preceded by a lblock check failure. I noticed
this in the bmbt stats:

$ pminfo -f xfs.btree.block_map

xfs.btree.block_map.lookup
value 39135

xfs.btree.block_map.compare
value 268432

xfs.btree.block_map.insrec
value 15786

xfs.btree.block_map.delrec
value 13884

xfs.btree.block_map.newroot
value 2

xfs.btree.block_map.killroot
value 0
.....

Very little coverage of root splits and merges. Indeed, on a 4k
filesystem, block_map.newroot and block_map.killroot are both zero.
i.e. the code is not exercised at all, and it's the only generic
btree infrastructure operation that is not exercised by a default run
of xfstests.

Turns out that on a 1k filesystem, generic/234 accounts for one of
those two root splits, and that is somewhat of a smoking gun. In
fact, it's the same problem we saw in the directory/attr code where
headers are memcpy()d from one block to another without updating the
self describing metadata.

Simple fix - when copying the header out of the root block, make
sure the block number is updated correctly.

Signed-off-by: Dave Chinner
Reviewed-by: Ben Myers
Signed-off-by: Ben Myers

(cherry picked from commit ade1335afef556df6538eb02e8c0dc91fbd9cc37)

xfs: fix implicit padding in directory and attr CRC formats

2013-06-14T20:59:16+00:00

Michael L. Semon has been testing CRC patches on a 32 bit system and
been seeing assert failures in the directory code from xfs/080.
Thanks to Michael's heroic efforts with printk debugging, we found
that the problem was that the last free space being left in the
directory structure was too small to fit a unused tag structure and
it was being corrupted and attempting to log a region out of bounds.
Hence the assert failure looked something like:

.....
#5 calling xfs_dir2_data_log_unused() 36 32
#1 4092 4095 4096
#2 8182 8183 4096
XFS: Assertion failed: first <= last && last < BBTOB(bp->b_length), file: fs/xfs/xfs_trans_buf.c, line: 568

Where #1 showed the first region of the dup being logged (i.e. the
last 4 bytes of a directory buffer) and #2 shows the corrupt values
being calculated from the length of the dup entry which overflowed
the size of the buffer.

It turns out that the problem was not in the logging code, nor in
the freespace handling code. It is an initial condition bug that
only shows up on 32 bit systems. When a new buffer is initialised,
where's the freespace that is set up:

[ 172.316249] calling xfs_dir2_leaf_addname() from xfs_dir_createname()
[ 172.316346] #9 calling xfs_dir2_data_log_unused()
[ 172.316351] #1 calling xfs_trans_log_buf() 60 63 4096
[ 172.316353] #2 calling xfs_trans_log_buf() 4094 4095 4096

Note the offset of the first region being logged? It's 60 bytes into
the buffer. Once I saw that, I pretty much knew that the bug was
going to be caused by this.

Essentially, all direct entries are rounded to 8 bytes in length,
and all entries start with an 8 byte alignment. This means that we
can decode inplace as variables are naturally aligned. With the
directory data supposedly starting on a 8 byte boundary, and all
entries padded to 8 bytes, the minimum freespace in a directory
block is supposed to be 8 bytes, which is large enough to fit a
unused data entry structure (6 bytes in size). The fact we only have
4 bytes of free space indicates a directory data block alignment
problem.

And what do you know - there's an implicit hole in the directory
data block header for the CRC format, which means the header is 60
byte on 32 bit intel systems and 64 bytes on 64 bit systems. Needs
padding. And while looking at the structures, I found the same
problem in the attr leaf header. Fix them both.

Note that this only affects 32 bit systems with CRCs enabled.
Everything else is just fine. Note that CRC enabled filesystems created
before this fix on such systems will not be readable with this fix
applied.

Reported-by: Michael L. Semon
Debugged-by: Michael L. Semon
Signed-off-by: Dave Chinner
Reviewed-by: Ben Myers
Signed-off-by: Ben Myers

(cherry picked from commit 8a1fd2950e1fe267e11fc8c85dcaa6b023b51b60)

xfs: don't emit v5 superblock warnings on write

2013-06-14T20:58:47+00:00

We write the superblock every 30s or so which results in the
verifier being called. Right now that results in this output
every 30s:

XFS (vda): Version 5 superblock detected. This kernel has EXPERIMENTAL support enabled!
Use of these features in this kernel is at your own risk!

And spamming the logs.

We don't need to check for whether we support v5 superblocks or
whether there are feature bits we don't support set as these are
only relevant when we first mount the filesytem. i.e. on superblock
read. Hence for the write verification we can just skip all the
checks (and hence verbose output) altogether.

Signed-off-by: Dave Chinner 
Reviewed-by: Brian Foster 
Signed-off-by: Ben Myers 

(cherry picked from commit 34510185abeaa5be9b178a41c0a03d30aec3db7e)

xfs: increase number of ACL entries for V5 superblocks

2013-06-06T15:52:15+00:00

The limit of 25 ACL entries is arbitrary, but baked into the on-disk
format.  For version 5 superblocks, increase it to the maximum nuber
of ACLs that can fit into a single xattr.

Signed-off-by: Dave Chinner 
Reviewed-by: Brian Foster 
Reviewed-by: Mark Tinguely 
Signed-off-by: Ben Myers 

(cherry picked from commit 5c87d4bc1a86bd6e6754ac3d6e111d776ddcfe57)

xfs: disable noattr2/attr2 mount options for CRC enabled filesystems

2013-06-06T15:51:34+00:00

attr2 format is always enabled for v5 superblock filesystems, so the
mount options to enable or disable it need to be cause mount errors.

Signed-off-by: Dave Chinner 
Reviewed-by: Brian Foster 
Signed-off-by: Ben Myers 

(cherry picked from commit d3eaace84e40bf946129e516dcbd617173c1cf14)