linux-toradex.git/fs/ext4, branch v4.9.96

ext4: don't allow r/w mounts if metadata blocks overlap the superblock

2018-04-24T07:34:15+00:00

commit 18db4b4e6fc31eda838dd1c1296d67dbcb3dc957 upstream.

If some metadata block, such as an allocation bitmap, overlaps the
superblock, it's very likely that if the file system is mounted
read/write, the results will not be pretty.  So disallow r/w mounts
for file systems corrupted in this particular way.

Backport notes:
3.18.y is missing bc98a42c1f7d ("VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb)")
and e462ec50cb5f ("VFS: Differentiate mount flags (MS_*) from internal superblock flags")
so we simply use the sb MS_RDONLY check from pre bc98a42c1f7d in place of the sb_rdonly
function used in the upstream variant of the patch.

Signed-off-by: Theodore Ts'o 
Cc: stable@vger.kernel.org
Signed-off-by: Harsh Shandilya 
Signed-off-by: Greg Kroah-Hartman

ext4: fail ext4_iget for root directory if unallocated

2018-04-24T07:34:12+00:00

commit 8e4b5eae5decd9dfe5a4ee369c22028f90ab4c44 upstream.

If the root directory has an i_links_count of zero, then when the file
system is mounted, then when ext4_fill_super() notices the problem and
tries to call iput() the root directory in the error return path,
ext4_evict_inode() will try to free the inode on disk, before all of
the file system structures are set up, and this will result in an OOPS
caused by a NULL pointer dereference.

This issue has been assigned CVE-2018-1092.

https://bugzilla.kernel.org/show_bug.cgi?id=199179
https://bugzilla.redhat.com/show_bug.cgi?id=1560777

Reported-by: Wen Xu 
Signed-off-by: Theodore Ts'o 
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

ext4: protect i_disksize update by i_data_sem in direct write path

2018-04-24T07:34:12+00:00

commit 73fdad00b208b139cf43f3163fbc0f67e4c6047c upstream.

i_disksize update should be protected by i_data_sem, by either taking
the lock explicitly or by using ext4_update_i_disksize() helper. But the
i_disksize updates in ext4_direct_IO_write() are not protected at all,
which may be racing with i_disksize updates in writeback path in
delalloc buffer write path.

This is found by code inspection, and I didn't hit any i_disksize
corruption due to this bug. Thanks to Jan Kara for catching this bug and
suggesting the fix!

Reported-by: Jan Kara 
Suggested-by: Jan Kara 
Signed-off-by: Eryu Guan 
Signed-off-by: Theodore Ts'o 
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

ext4: don't update checksum of new initialized bitmaps

2018-04-24T07:34:12+00:00

commit 044e6e3d74a3d7103a0c8a9305dfd94d64000660 upstream.

When reading the inode or block allocation bitmap, if the bitmap needs
to be initialized, do not update the checksum in the block group
descriptor.  That's because we're not set up to journal those changes.
Instead, just set the verified bit on the bitmap block, so that it's
not necessary to validate the checksum.

When a block or inode allocation actually happens, at that point the
checksum will be calculated, and update of the bg descriptor block
will be properly journalled.

Signed-off-by: Theodore Ts'o 
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

ext4: fix off-by-one on max nr_pages in ext4_find_unwritten_pgoff()

2018-04-13T17:48:06+00:00

[ Upstream commit 624327f8794704c5066b11a52f9da6a09dce7f9a ]

ext4_find_unwritten_pgoff() is used to search for offset of hole or
data in page range [index, end] (both inclusive), and the max number
of pages to search should be at least one, if end == index.
Otherwise the only page is missed and no hole or data is found,
which is not correct.

When block size is smaller than page size, this can be demonstrated
by preallocating a file with size smaller than page size and writing
data to the last block. E.g. run this xfs_io command on a 1k block
size ext4 on x86_64 host.

  # xfs_io -fc "falloc 0 3k" -c "pwrite 2k 1k" \
  	    -c "seek -d 0" /mnt/ext4/testfile
  wrote 1024/1024 bytes at offset 2048
  1 KiB, 1 ops; 0.0000 sec (42.459 MiB/sec and 43478.2609 ops/sec)
  Whence  Result
  DATA    EOF

Data at offset 2k was missed, and lseek(2) returned ENXIO.

This is unconvered by generic/285 subtest 07 and 08 on ppc64 host,
where pagesize is 64k. Because a recent change to generic/285
reduced the preallocated file size to smaller than 64k.

Signed-off-by: Eryu Guan 
Signed-off-by: Theodore Ts'o 
Reviewed-by: Jan Kara 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ext4: handle the rest of ext4_mb_load_buddy() ENOMEM errors

2018-04-13T17:48:02+00:00

[ Upstream commit 9651e6b2e20648d04d5e1fe6479a3056047e8781 ]

I've got another report about breaking ext4 by ENOMEM error returned from
ext4_mb_load_buddy() caused by memory shortage in memory cgroup.
This time inside ext4_discard_preallocations().

This patch replaces ext4_error() with ext4_warning() where errors returned
from ext4_mb_load_buddy() are not fatal and handled by caller:
* ext4_mb_discard_group_preallocations() - called before generating ENOSPC,
  we'll try to discard other group or return ENOSPC into user-space.
* ext4_trim_all_free() - just stop trimming and return ENOMEM from ioctl.

Some callers cannot handle errors, thus __GFP_NOFAIL is used for them:
* ext4_discard_preallocations()
* ext4_mb_discard_lg_preallocations()

Fixes: adb7ef600cc9 ("ext4: use __GFP_NOFAIL in ext4_free_blocks()")
Signed-off-by: Konstantin Khlebnikov 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ext4: inplace xattr block update fails to deduplicate blocks

2018-03-18T10:18:54+00:00

commit ec00022030da5761518476096626338bd67df57a upstream.

When an xattr block has a single reference, block is updated inplace
and it is reinserted to the cache. Later, a cache lookup is performed
to see whether an existing block has the same contents. This cache
lookup will most of the time return the just inserted entry so
deduplication is not achieved.

Running the following test script will produce two xattr blocks which
can be observed in "File ACL: " line of debugfs output:

  mke2fs -b 1024 -I 128 -F -O extent /dev/sdb 1G
  mount /dev/sdb /mnt/sdb

  touch /mnt/sdb/{x,y}

  setfattr -n user.1 -v aaa /mnt/sdb/x
  setfattr -n user.2 -v bbb /mnt/sdb/x

  setfattr -n user.1 -v aaa /mnt/sdb/y
  setfattr -n user.2 -v bbb /mnt/sdb/y

  debugfs -R 'stat x' /dev/sdb | cat
  debugfs -R 'stat y' /dev/sdb | cat

This patch defers the reinsertion to the cache so that we can locate
other blocks with the same contents.

Signed-off-by: Tahsin Erdogan 
Signed-off-by: Theodore Ts'o 
Reviewed-by: Andreas Dilger 
Signed-off-by: Tommi Rantala 
Signed-off-by: Greg Kroah-Hartman

ext4: save error to disk in __ext4_grp_locked_error()

2018-02-22T14:43:48+00:00

commit 06f29cc81f0350261f59643a505010531130eea0 upstream.

In the function __ext4_grp_locked_error(), __save_error_info()
is called to save error info in super block block, but does not sync
that information to disk to info the subsequence fsck after reboot.

This patch writes the error information to disk.  After this patch,
I think there is no obvious EXT4 error handle branches which leads to
"Remounting filesystem read-only" will leave the disk partition miss
the subsequence fsck.

Signed-off-by: Zhouyi Zhou 
Signed-off-by: Theodore Ts'o 
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

ext4: fix a race in the ext4 shutdown path

2018-02-22T14:43:48+00:00

commit abbc3f9395c76d554a9ed27d4b1ebfb5d9b0e4ca upstream.

This patch fixes a race between the shutdown path and bio completion
handling. In the ext4 direct io path with async io, after submitting a
bio to the block layer, if journal starting fails,
ext4_direct_IO_write() would bail out pretending that the IO
failed. The caller would have had no way of knowing whether or not the
IO was successfully submitted. So instead, we return -EIOCBQUEUED in
this case. Now, the caller knows that the IO was submitted.  The bio
completion handler takes care of the error.

Tested: Ran the shutdown xfstest test 461 in loop for over 2 hours across
4 machines resulting in over 400 runs. Verified that the race didn't
occur. Usually the race was seen in about 20-30 iterations.

Signed-off-by: Harshad Shirwadkar 
Signed-off-by: Theodore Ts'o 
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

ext4: fix crash when a directory's i_size is too small

2017-12-20T09:07:17+00:00

commit 9d5afec6b8bd46d6ed821aa1579634437f58ef1f upstream.

On a ppc64 machine, when mounting a fuzzed ext2 image (generated by
fsfuzzer) the following call trace is seen,

VFS: brelse: Trying to free free buffer
WARNING: CPU: 1 PID: 6913 at /root/repos/linux/fs/buffer.c:1165 .__brelse.part.6+0x24/0x40
.__brelse.part.6+0x20/0x40 (unreliable)
.ext4_find_entry+0x384/0x4f0
.ext4_lookup+0x84/0x250
.lookup_slow+0xdc/0x230
.walk_component+0x268/0x400
.path_lookupat+0xec/0x2d0
.filename_lookup+0x9c/0x1d0
.vfs_statx+0x98/0x140
.SyS_newfstatat+0x48/0x80
system_call+0x58/0x6c

This happens because the directory that ext4_find_entry() looks up has
inode->i_size that is less than the block size of the filesystem. This
causes 'nblocks' to have a value of zero. ext4_bread_batch() ends up not
reading any of the directory file's blocks. This renders the entries in
bh_use[] array to continue to have garbage data. buffer_uptodate() on
bh_use[0] can then return a zero value upon which brelse() function is
invoked.

This commit fixes the bug by returning -ENOENT when the directory file
has no associated blocks.

Reported-by: Abdul Haleem 
Signed-off-by: Chandan Rajendra 
Signed-off-by: Greg Kroah-Hartman