linux-toradex.git/fs/ext4, branch v3.2.55

ext4: add explicit casts when masking cluster sizes

2014-02-15T19:20:15+00:00

commit f5a44db5d2d677dfbf12deee461f85e9ec633961 upstream.

The missing casts can cause the high 64-bits of the physical blocks to
be lost.  Set up new macros which allows us to make sure the right
thing happen, even if at some point we end up supporting larger
logical block numbers.

Thanks to the Emese Revfy and the PaX security team for reporting this
issue.

Reported-by: PaX Team 
Reported-by: Emese Revfy 
Signed-off-by: "Theodore Ts'o" 
[bwh: Backported to 3.2:
 - Adjust context
 - Drop inapplicable change to ext4_ext_rm_leaf()]
Signed-off-by: Ben Hutchings

ext4: fix del_timer() misuse for ->s_err_report

2014-02-15T19:20:12+00:00

commit 9105bb149bbbc555d2e11ba5166dfe7a24eae09e upstream.

That thing should be del_timer_sync(); consider what happens
if ext4_put_super() call of del_timer() happens to come just as it's
getting run on another CPU.  Since that timer reschedules itself
to run next day, you are pretty much guaranteed that you'll end up
with kfree'd scheduled timer, with usual fun consequences.  AFAICS,
that's -stable fodder all way back to 2010... [the second del_timer_sync()
is almost certainly not needed, but it doesn't hurt either]

Signed-off-by: Al Viro 
Signed-off-by: "Theodore Ts'o" 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

ext4: check for overlapping extents in ext4_valid_extent_entries()

2014-02-15T19:20:12+00:00

commit 5946d089379a35dda0e531710b48fca05446a196 upstream.

A corrupted ext4 may have out of order leaf extents, i.e.

extent: lblk 0--1023, len 1024, pblk 9217, flags: LEAF UNINIT
extent: lblk 1000--2047, len 1024, pblk 10241, flags: LEAF UNINIT
             ^^^^ overlap with previous extent

Reading such extent could hit BUG_ON() in ext4_es_cache_extent().

	BUG_ON(end < lblk);

The problem is that __read_extent_tree_block() tries to cache holes as
well but assumes 'lblk' is greater than 'prev' and passes underflowed
length to ext4_es_cache_extent(). Fix it by checking for overlapping
extents in ext4_valid_extent_entries().

I hit this when fuzz testing ext4, and am able to reproduce it by
modifying the on-disk extent by hand.

Also add the check for (ee_block + len - 1) in ext4_valid_extent() to
make sure the value is not overflow.

Ran xfstests on patched ext4 and no regression.

Cc: Lukáš Czerner 
Signed-off-by: Eryu Guan 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Ben Hutchings

ext4: fix use-after-free in ext4_mb_new_blocks

2014-02-15T19:20:12+00:00

commit 4e8d2139802ce4f41936a687f06c560b12115247 upstream.

ext4_mb_put_pa should hold pa->pa_lock before accessing pa->pa_count.
While ext4_mb_use_preallocated checks pa->pa_deleted first and then
increments pa->count later, ext4_mb_put_pa decrements pa->pa_count
before holding pa->pa_lock and then sets pa->pa_deleted.

* Free sequence
ext4_mb_put_pa (1):		atomic_dec_and_test pa->pa_count
ext4_mb_put_pa (2):		lock pa->pa_lock
ext4_mb_put_pa (3):			check pa->pa_deleted
ext4_mb_put_pa (4):			set pa->pa_deleted=1
ext4_mb_put_pa (5):		unlock pa->pa_lock
ext4_mb_put_pa (6):		remove pa from a list
ext4_mb_pa_callback:		free pa

* Use sequence
ext4_mb_use_preallocated (1):	iterate over preallocation
ext4_mb_use_preallocated (2):	lock pa->pa_lock
ext4_mb_use_preallocated (3):		check pa->pa_deleted
ext4_mb_use_preallocated (4):		increase pa->pa_count
ext4_mb_use_preallocated (5):	unlock pa->pa_lock
ext4_mb_release_context:	access pa

* Use-after-free sequence
[initial status]		pa_deleted = 0, pa_count = 1>
ext4_mb_use_preallocated (1):	iterate over preallocation
ext4_mb_use_preallocated (2):	lock pa->pa_lock
ext4_mb_use_preallocated (3):		check pa->pa_deleted
ext4_mb_put_pa (1):		atomic_dec_and_test pa->pa_count
[pa_count decremented]		pa_deleted = 0, pa_count = 0>
ext4_mb_use_preallocated (4):		increase pa->pa_count
[pa_count incremented]		pa_deleted = 0, pa_count = 1>
ext4_mb_use_preallocated (5):	unlock pa->pa_lock
ext4_mb_put_pa (2):		lock pa->pa_lock
ext4_mb_put_pa (3):			check pa->pa_deleted
ext4_mb_put_pa (4):			set pa->pa_deleted=1
[race condition!]		pa_deleted = 1, pa_count = 1>
ext4_mb_put_pa (5):		unlock pa->pa_lock
ext4_mb_put_pa (6):		remove pa from a list
ext4_mb_pa_callback:		free pa
ext4_mb_release_context:	access pa

AddressSanitizer has detected use-after-free in ext4_mb_new_blocks
Bug report: http://goo.gl/rG1On3

Signed-off-by: Junho Ryu 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Ben Hutchings

ext4: call ext4_error_inode() if jbd2_journal_dirty_metadata() fails

2014-02-15T19:20:12+00:00

commit ae1495b12df1897d4f42842a7aa7276d920f6290 upstream.

While it's true that errors can only happen if there is a bug in
jbd2_journal_dirty_metadata(), if a bug does happen, we need to halt
the kernel or remount the file system read-only in order to avoid
further data loss.  The ext4_journal_abort_handle() function doesn't
do any of this, and while it's likely that this call (since it doesn't
adjust refcounts) will likely result in the file system eventually
deadlocking since the current transaction will never be able to close,
it's much cleaner to call let ext4's error handling system deal with
this situation.

There's a separate bug here which is that if certain jbd2 errors
errors occur and file system is mounted errors=continue, the file
system will probably eventually end grind to a halt as described
above.  But things have been this way in a long time, and usually when
we have these sorts of errors it's pretty much a disaster --- and
that's why the jbd2 layer aggressively retries memory allocations,
which is the most likely cause of these jbd2 errors.

Signed-off-by: "Theodore Ts'o" 
Reviewed-by: Jan Kara 
[bwh: Backported to 3.2: drop logging of missing transaction debug data]
Signed-off-by: Ben Hutchings

ext4: avoid bh leak in retry path of ext4_expand_extra_isize_ea()

2014-01-03T04:33:16+00:00

commit dcb9917ba041866686fe152850364826c4622a36 upstream.

Reported-by: Dave Jones 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Ben Hutchings

ext4: fix memory leak in xattr

2013-11-28T14:02:03+00:00

commit 6e4ea8e33b2057b85d75175dd89b93f5e26de3bc upstream.

If we take the 2nd retry path in ext4_expand_extra_isize_ea, we
potentionally return from the function without having freed these
allocations.  If we don't do the return, we over-write the previous
allocation pointers, so we leak either way.

Spotted with Coverity.

[ Fixed by tytso to set is and bs to NULL after freeing these
  pointers, in case in the retry loop we later end up triggering an
  error causing a jump to cleanup, at which point we could have a double
  free bug. -- Ted ]

Signed-off-by: Dave Jones 
Signed-off-by: "Theodore Ts'o" 
Reviewed-by: Eric Sandeen 
Signed-off-by: Ben Hutchings

ext4: return 32/64-bit dir name hash according to usage type

2013-11-28T14:01:58+00:00

commit d1f5273e9adb40724a85272f248f210dc4ce919a upstream.

Traditionally ext2/3/4 has returned a 32-bit hash value from llseek()
to appease NFSv2, which can only handle a 32-bit cookie for seekdir()
and telldir().  However, this causes problems if there are 32-bit hash
collisions, since the NFSv2 server can get stuck resending the same
entries from the directory repeatedly.

Allow ext4 to return a full 64-bit hash (both major and minor) for
telldir to decrease the chance of hash collisions.  This still needs
integration on the NFS side.

Patch-updated-by: Bernd Schubert 
(blame me if something is not correct)

Signed-off-by: Fan Yong 
Signed-off-by: Andreas Dilger 
Signed-off-by: Bernd Schubert 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Jonathan Nieder 
Signed-off-by: Ben Hutchings

ext4: avoid hang when mounting non-journal filesystems with orphan list

2013-10-26T20:06:13+00:00

commit 0e9a9a1ad619e7e987815d20262d36a2f95717ca upstream.

When trying to mount a file system which does not contain a journal,
but which does have a orphan list containing an inode which needs to
be truncated, the mount call with hang forever in
ext4_orphan_cleanup() because ext4_orphan_del() will return
immediately without removing the inode from the orphan list, leading
to an uninterruptible loop in kernel code which will busy out one of
the CPU's on the system.

This can be trivially reproduced by trying to mount the file system
found in tests/f_orphan_extents_inode/image.gz from the e2fsprogs
source tree.  If a malicious user were to put this on a USB stick, and
mount it on a Linux desktop which has automatic mounts enabled, this
could be considered a potential denial of service attack.  (Not a big
deal in practice, but professional paranoids worry about such things,
and have even been known to allocate CVE numbers for such problems.)

-js: This is a fix for CVE-2013-2015.

Signed-off-by: "Theodore Ts'o" 
Reviewed-by: Zheng Liu 
Acked-by: Jan Kara 
Signed-off-by: Jiri Slaby 
Signed-off-by: Ben Hutchings

jbd2: Fix use after free after error in jbd2_journal_dirty_metadata()

2013-09-10T00:57:22+00:00

commit 91aa11fae1cf8c2fd67be0609692ea9741cdcc43 upstream.

When jbd2_journal_dirty_metadata() returns error,
__ext4_handle_dirty_metadata() stops the handle. However callers of this
function do not count with that fact and still happily used now freed
handle. This use after free can result in various issues but very likely
we oops soon.

The motivation of adding __ext4_journal_stop() into
__ext4_handle_dirty_metadata() in commit 9ea7a0df seems to be only to
improve error reporting. So replace __ext4_journal_stop() with
ext4_journal_abort_handle() which was there before that commit and add
WARN_ON_ONCE() to dump stack to provide useful information.

Reported-by: Sage Weil 
Signed-off-by: Jan Kara 
Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Ben Hutchings