linux-toradex.git/fs/ext4, branch v4.4.109

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

2017-12-20T09:04:52+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

ext4: fix fdatasync(2) after fallocate(2) operation

2017-12-20T09:04:52+00:00

commit c894aa97577e47d3066b27b32499ecf899bfa8b0 upstream.

Currently, fallocate(2) with KEEP_SIZE followed by a fdatasync(2)
then crash, we'll see wrong allocated block number (stat -c %b), the
blocks allocated beyond EOF are all lost. fstests generic/468
exposes this bug.

Commit 67a7d5f561f4 ("ext4: fix fdatasync(2) after extent
manipulation operations") fixed all the other extent manipulation
operation paths such as hole punch, zero range, collapse range etc.,
but forgot the fallocate case.

So similarly, fix it by recording the correct journal tid in ext4
inode in fallocate(2) path, so that ext4_sync_file() will wait for
the right tid to be committed on fdatasync(2).

This addresses the test failure in xfstests test generic/468.

Signed-off-by: Eryu Guan 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

fscrypt: lock mutex before checking for bounce page pool

2017-11-30T08:37:25+00:00

commit a0b3bc855374c50b5ea85273553485af48caf2f7 upstream.

fscrypt_initialize(), which allocates the global bounce page pool when
an encrypted file is first accessed, uses "double-checked locking" to
try to avoid locking fscrypt_init_mutex.  However, it doesn't use any
memory barriers, so it's theoretically possible for a thread to observe
a bounce page pool which has not been fully initialized.  This is a
classic bug with "double-checked locking".

While "only a theoretical issue" in the latest kernel, in pre-4.8
kernels the pointer that was checked was not even the last to be
initialized, so it was easily possible for a crash (NULL pointer
dereference) to happen.  This was changed only incidentally by the large
refactor to use fs/crypto/.

Solve both problems in a trivial way that can easily be backported: just
always take the mutex.  It's theoretically less efficient, but it
shouldn't be noticeable in practice as the mutex is only acquired very
briefly once per encrypted file.

Later I'd like to make this use a helper macro like DO_ONCE().  However,
DO_ONCE() runs in atomic context, so we'd need to add a new macro that
allows blocking.

Signed-off-by: Eric Biggers 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ext4: fix interaction between i_size, fallocate, and delalloc after a crash

2017-11-30T08:37:21+00:00

commit 51e3ae81ec58e95f10a98ef3dd6d7bce5d8e35a2 upstream.

If there are pending writes subject to delayed allocation, then i_size
will show size after the writes have completed, while i_disksize
contains the value of i_size on the disk (since the writes have not
been persisted to disk).

If fallocate(2) is called with the FALLOC_FL_KEEP_SIZE flag, either
with or without the FALLOC_FL_ZERO_RANGE flag set, and the new size
after the fallocate(2) is between i_size and i_disksize, then after a
crash, if a journal commit has resulted in the changes made by the
fallocate() call to be persisted after a crash, but the delayed
allocation write has not resolved itself, i_size would not be updated,
and this would cause the following e2fsck complaint:

Inode 12, end of extent exceeds allowed value
	(logical block 33, physical block 33441, len 7)

This can only take place on a sparse file, where the fallocate(2) call
is allocating blocks in a range which is before a pending delayed
allocation write which is extending i_size.  Since this situation is
quite rare, and the window in which the crash must take place is
typically < 30 seconds, in practice this condition will rarely happen.

Nevertheless, it can be triggered in testing, and in particular by
xfstests generic/456.

Signed-off-by: Theodore Ts'o 
Reported-by: Amir Goldstein 
Signed-off-by: Greg Kroah-Hartman

ext4: fix data exposure after a crash

2017-11-21T08:21:17+00:00

commit 06bd3c36a733ac27962fea7d6f47168841376824 upstream.

Huang has reported that in his powerfail testing he is seeing stale
block contents in some of recently allocated blocks although he mounts
ext4 in data=ordered mode. After some investigation I have found out
that indeed when delayed allocation is used, we don't add inode to
transaction's list of inodes needing flushing before commit. Originally
we were doing that but commit f3b59291a69d removed the logic with a
flawed argument that it is not needed.

The problem is that although for delayed allocated blocks we write their
contents immediately after allocating them, there is no guarantee that
the IO scheduler or device doesn't reorder things and thus transaction
allocating blocks and attaching them to inode can reach stable storage
before actual block contents. Actually whenever we attach freshly
allocated blocks to inode using a written extent, we should add inode to
transaction's ordered inode list to make sure we properly wait for block
contents to be written before committing the transaction. So that is
what we do in this patch. This also handles other cases where stale data
exposure was possible - like filling hole via mmap in
data=ordered,nodelalloc mode.

The only exception to the above rule are extending direct IO writes where
blkdev_direct_IO() waits for IO to complete before increasing i_size and
thus stale data exposure is not possible. For now we don't complicate
the code with optimizing this special case since the overhead is pretty
low. In case this is observed to be a performance problem we can always
handle it using a special flag to ext4_map_blocks().

Fixes: f3b59291a69d0b734be1fc8be489fef2dd846d3d
Reported-by: "HUANG Weller (CM/ESW12-CN)" 
Tested-by: "HUANG Weller (CM/ESW12-CN)" 
Signed-off-by: Jan Kara 
Signed-off-by: Theodore Ts'o 
[bwh: Backported to 4.4:
 - Drop check for EXT4_GET_BLOCKS_ZERO flag
 - Adjust context]
Signed-off-by: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

ext4: do not use stripe_width if it is not set

2017-11-08T09:06:29+00:00

[ Upstream commit 5469d7c3087ecaf760f54b447f11af6061b7c897 ]

Avoid using stripe_width for sbi->s_stripe value if it is not actually
set. It prevents using the stride for sbi->s_stripe.

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

ext4: fix stripe-unaligned allocations

2017-11-08T09:06:29+00:00

[ Upstream commit d9b22cf9f5466a057f2a4f1e642b469fa9d73117 ]

When a filesystem is created using:

	mkfs.ext4 -b 4096 -E stride=512 

and we try to allocate 64MB extent, we will end up directly in
ext4_mb_complex_scan_group(). This is because the request is detected
as power-of-two allocation (so we start in ext4_mb_regular_allocator()
with ac_criteria == 0) however the check before
ext4_mb_simple_scan_group() refuses the direct buddy scan because the
allocation request is too large. Since cr == 0, the check whether we
should use ext4_mb_scan_aligned() fails as well and we fall back to
ext4_mb_complex_scan_group().

Fix the problem by checking for upper limit on power-of-two requests
directly when detecting them.

Reported-by: Ross Zwisler 
Signed-off-by: Jan Kara 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

fscrypt: fix dereference of NULL user_key_payload

2017-10-27T08:23:18+00:00

commit d60b5b7854c3d135b869f74fb93eaf63cbb1991a upstream.

When an fscrypt-encrypted file is opened, we request the file's master
key from the keyrings service as a logon key, then access its payload.
However, a revoked key has a NULL payload, and we failed to check for
this.  request_key() *does* skip revoked keys, but there is still a
window where the key can be revoked before we acquire its semaphore.

Fix it by checking for a NULL payload, treating it like a key which was
already revoked at the time it was requested.

Fixes: 88bd6ccdcdd6 ("ext4 crypto: add encryption key management facilities")
Reviewed-by: James Morris 
Cc:     [v4.1+]
Signed-off-by: Eric Biggers 
Signed-off-by: David Howells 
Signed-off-by: Greg Kroah-Hartman

ext4: in ext4_seek_{hole,data}, return -ENXIO for negative offsets

2017-10-18T07:20:40+00:00

commit 1bd8d6cd3e413d64e543ec3e69ff43e75a1cf1ea upstream.

In the ext4 implementations of SEEK_HOLE and SEEK_DATA, make sure we
return -ENXIO for negative offsets instead of banging around inside
the extent code and returning -EFSCORRUPTED.

Reported-by: Mateusz S 
Signed-off-by: Darrick J. Wong 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ext4: don't allow encrypted operations without keys

2017-10-12T09:27:35+00:00

commit 173b8439e1ba362007315868928bf9d26e5cc5a6 upstream.

While we allow deletes without the key, the following should not be
permitted:

# cd /vdc/encrypted-dir-without-key
# ls -l
total 4
-rw-r--r-- 1 root root   0 Dec 27 22:35 6,LKNRJsp209FbXoSvJWzB
-rw-r--r-- 1 root root 286 Dec 27 22:35 uRJ5vJh9gE7vcomYMqTAyD
# mv uRJ5vJh9gE7vcomYMqTAyD  6,LKNRJsp209FbXoSvJWzB

Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman