linux-stable.git/drivers/md, branch v6.6.63

dm-unstriped: cast an operand to sector_t to prevent potential uint32_t overflow

2024-11-14T12:19:37+00:00

commit 5a4510c762fc04c74cff264cd4d9e9f5bf364bae upstream.

This was found by a static analyzer.
There may be a potential integer overflow issue in
unstripe_ctr(). uc->unstripe_offset and uc->unstripe_width are
defined as "sector_t"(uint64_t), while uc->unstripe,
uc->chunk_size and uc->stripes are all defined as "uint32_t".
The result of the calculation will be limited to "uint32_t"
without correct casting.
So, we recommend adding an extra cast to prevent potential
integer overflow.

Fixes: 18a5bf270532 ("dm: add unstriped target")
Signed-off-by: Zichen Xie 
Signed-off-by: Mikulas Patocka 
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

dm cache: fix potential out-of-bounds access on the first resume

2024-11-14T12:19:37+00:00

commit c0ade5d98979585d4f5a93e4514c2e9a65afa08d upstream.

Out-of-bounds access occurs if the fast device is expanded unexpectedly
before the first-time resume of the cache table. This happens because
expanding the fast device requires reloading the cache table for
cache_create to allocate new in-core data structures that fit the new
size, and the check in cache_preresume is not performed during the
first resume, leading to the issue.

Reproduce steps:

1. prepare component devices:

dmsetup create cmeta --table "0 8192 linear /dev/sdc 0"
dmsetup create cdata --table "0 65536 linear /dev/sdc 8192"
dmsetup create corig --table "0 524288 linear /dev/sdc 262144"
dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct

2. load a cache table of 512 cache blocks, and deliberately expand the
   fast device before resuming the cache, making the in-core data
   structures inadequate.

dmsetup create cache --notable
dmsetup reload cache --table "0 524288 cache /dev/mapper/cmeta \
/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0"
dmsetup reload cdata --table "0 131072 linear /dev/sdc 8192"
dmsetup resume cdata
dmsetup resume cache

3. suspend the cache to write out the in-core dirty bitset and hint
   array, leading to out-of-bounds access to the dirty bitset at offset
   0x40:

dmsetup suspend cache

KASAN reports:

  BUG: KASAN: vmalloc-out-of-bounds in is_dirty_callback+0x2b/0x80
  Read of size 8 at addr ffffc90000085040 by task dmsetup/90

  (...snip...)
  The buggy address belongs to the virtual mapping at
   [ffffc90000085000, ffffc90000087000) created by:
   cache_ctr+0x176a/0x35f0

  (...snip...)
  Memory state around the buggy address:
   ffffc90000084f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
   ffffc90000084f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
  >ffffc90000085000: 00 00 00 00 00 00 00 00 f8 f8 f8 f8 f8 f8 f8 f8
                                             ^
   ffffc90000085080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
   ffffc90000085100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8

Fix by checking the size change on the first resume.

Signed-off-by: Ming-Hung Tsai 
Fixes: f494a9c6b1b6 ("dm cache: cache shrinking support")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka 
Acked-by: Joe Thornber 
Signed-off-by: Greg Kroah-Hartman

dm cache: optimize dirty bit checking with find_next_bit when resizing

2024-11-14T12:19:37+00:00

commit f484697e619a83ecc370443a34746379ad99d204 upstream.

When shrinking the fast device, dm-cache iteratively searches for a
dirty bit among the cache blocks to be dropped, which is less efficient.
Use find_next_bit instead, as it is twice as fast as the iterative
approach with test_bit.

Signed-off-by: Ming-Hung Tsai 
Fixes: f494a9c6b1b6 ("dm cache: cache shrinking support")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka 
Acked-by: Joe Thornber 
Signed-off-by: Greg Kroah-Hartman

dm cache: fix out-of-bounds access to the dirty bitset when resizing

2024-11-14T12:19:37+00:00

commit 792227719725497ce10a8039803bec13f89f8910 upstream.

dm-cache checks the dirty bits of the cache blocks to be dropped when
shrinking the fast device, but an index bug in bitset iteration causes
out-of-bounds access.

Reproduce steps:

1. create a cache device of 1024 cache blocks (128 bytes dirty bitset)

dmsetup create cmeta --table "0 8192 linear /dev/sdc 0"
dmsetup create cdata --table "0 131072 linear /dev/sdc 8192"
dmsetup create corig --table "0 524288 linear /dev/sdc 262144"
dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct
dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \
/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0"

2. shrink the fast device to 512 cache blocks, triggering out-of-bounds
   access to the dirty bitset (offset 0x80)

dmsetup suspend cache
dmsetup reload cdata --table "0 65536 linear /dev/sdc 8192"
dmsetup resume cdata
dmsetup resume cache

KASAN reports:

  BUG: KASAN: vmalloc-out-of-bounds in cache_preresume+0x269/0x7b0
  Read of size 8 at addr ffffc900000f3080 by task dmsetup/131

  (...snip...)
  The buggy address belongs to the virtual mapping at
   [ffffc900000f3000, ffffc900000f5000) created by:
   cache_ctr+0x176a/0x35f0

  (...snip...)
  Memory state around the buggy address:
   ffffc900000f2f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
   ffffc900000f3000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  >ffffc900000f3080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                     ^
   ffffc900000f3100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
   ffffc900000f3180: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8

Fix by making the index post-incremented.

Signed-off-by: Ming-Hung Tsai 
Fixes: f494a9c6b1b6 ("dm cache: cache shrinking support")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka 
Acked-by: Joe Thornber 
Signed-off-by: Greg Kroah-Hartman

dm cache: fix flushing uninitialized delayed_work on cache_ctr error

2024-11-14T12:19:36+00:00

commit 135496c208ba26fd68cdef10b64ed7a91ac9a7ff upstream.

An unexpected WARN_ON from flush_work() may occur when cache creation
fails, caused by destroying the uninitialized delayed_work waker in the
error path of cache_create(). For example, the warning appears on the
superblock checksum error.

Reproduce steps:

dmsetup create cmeta --table "0 8192 linear /dev/sdc 0"
dmsetup create cdata --table "0 65536 linear /dev/sdc 8192"
dmsetup create corig --table "0 524288 linear /dev/sdc 262144"
dd if=/dev/urandom of=/dev/mapper/cmeta bs=4k count=1 oflag=direct
dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \
/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0"

Kernel logs:

(snip)
WARNING: CPU: 0 PID: 84 at kernel/workqueue.c:4178 __flush_work+0x5d4/0x890

Fix by pulling out the cancel_delayed_work_sync() from the constructor's
error path. This patch doesn't affect the use-after-free fix for
concurrent dm_resume and dm_destroy (commit 6a459d8edbdb ("dm cache: Fix
UAF in destroy()")) as cache_dtr is not changed.

Signed-off-by: Ming-Hung Tsai 
Fixes: 6a459d8edbdb ("dm cache: Fix UAF in destroy()")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka 
Acked-by: Joe Thornber 
Signed-off-by: Greg Kroah-Hartman

dm cache: correct the number of origin blocks to match the target length

2024-11-14T12:19:36+00:00

commit 235d2e739fcbe964c9ce179b4c991025662dcdb6 upstream.

When creating a cache device, the actual size of the cache origin might
be greater than the specified cache target length. In such case, the
number of origin blocks should match the cache target length, not the
full size of the origin device, since access beyond the cache target is
not possible. This issue occurs when reducing the origin device size
using lvm, as lvreduce preloads the new cache table before resuming the
cache origin, which can result in incorrect sizes for the discard bitset
and smq hotspot blocks.

Reproduce steps:

1. create a cache device consists of 4096 origin blocks

dmsetup create cmeta --table "0 8192 linear /dev/sdc 0"
dmsetup create cdata --table "0 65536 linear /dev/sdc 8192"
dmsetup create corig --table "0 524288 linear /dev/sdc 262144"
dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct
dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \
/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0"

2. reduce the cache origin to 2048 oblocks, in lvreduce's approach

dmsetup reload corig --table "0 262144 linear /dev/sdc 262144"
dmsetup reload cache --table "0 262144 cache /dev/mapper/cmeta \
/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0"
dmsetup suspend cache
dmsetup suspend corig
dmsetup suspend cdata
dmsetup suspend cmeta
dmsetup resume corig
dmsetup resume cdata
dmsetup resume cmeta
dmsetup resume cache

3. shutdown the cache, and check the number of discard blocks in
   superblock. The value is expected to be 2048, but actually is 4096.

dmsetup remove cache corig cdata cmeta
dd if=/dev/sdc bs=1c count=8 skip=224 2>/dev/null | hexdump -e '1/8 "%u\n"'

Fix by correcting the origin_blocks initialization in cache_create and
removing the unused origin_sectors from struct cache_args accordingly.

Signed-off-by: Ming-Hung Tsai 
Fixes: c6b4fcbad044 ("dm: add cache target")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka 
Acked-by: Joe Thornber 
Signed-off-by: Greg Kroah-Hartman

Revert: "dm-verity: restart or panic on an I/O error"

2024-10-04T14:30:05+00:00

commit 462763212dd71c41f092b48eaa352bc1f5ed5d66 upstream.

This reverts commit e6a3531dd542cb127c8de32ab1e54a48ae19962b.

The problem that the commit e6a3531dd542cb127c8de32ab1e54a48ae19962b
fixes was reported as a security bug, but Google engineers working on
Android and ChromeOS didn't want to change the default behavior, they
want to get -EIO rather than restarting the system, so I am reverting
that commit.

Note also that calling machine_restart from the I/O handling code is
potentially unsafe (the reboot notifiers may wait for the bio that
triggered the restart), but Android uses the reboot notifiers to store
the reboot reason into the PMU microcontroller, so machine_restart must
be used.

Signed-off-by: Mikulas Patocka 
Cc: stable@vger.kernel.org
Fixes: e6a3531dd542 ("dm-verity: restart or panic on an I/O error")
Suggested-by: Sami Tolvanen 
Suggested-by: Will Drewry 
Signed-off-by: Greg Kroah-Hartman

dm-verity: restart or panic on an I/O error

2024-10-04T14:30:02+00:00

commit e6a3531dd542cb127c8de32ab1e54a48ae19962b upstream.

Maxim Suhanov reported that dm-verity doesn't crash if an I/O error
happens. In theory, this could be used to subvert security, because an
attacker can create sectors that return error with the Write Uncorrectable
command. Some programs may misbehave if they have to deal with EIO.

This commit fixes dm-verity, so that if "panic_on_corruption" or
"restart_on_corruption" was specified and an I/O error happens, the
machine will panic or restart.

This commit also changes kernel_restart to emergency_restart -
kernel_restart calls reboot notifiers and these reboot notifiers may wait
for the bio that failed. emergency_restart doesn't call the notifiers.

Reported-by: Maxim Suhanov 
Signed-off-by: Mikulas Patocka 
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

Revert "dm: requeue IO if mapping table not yet available"

2024-10-04T14:29:40+00:00

[ Upstream commit c8691cd0fc11197515ed148de0780d927bfca38b ]

This reverts commit fa247089de9936a46e290d4724cb5f0b845600f5.

The following sequence of commands causes a livelock - there will be
workqueue process looping and consuming 100% CPU:

dmsetup create --notable test
truncate -s 1MiB testdata
losetup /dev/loop0 testdata
dmsetup load test --table '0 2048 linear /dev/loop0 0'
dd if=/dev/zero of=/dev/dm-0 bs=16k count=1 conv=fdatasync

The livelock is caused by the commit fa247089de99. The commit claims that
it fixes a race condition, however, it is unknown what the actual race
condition is and what program is involved in the race condition.

When the inactive table is loaded, the nodes /dev/dm-0 and
/sys/block/dm-0 are created. /dev/dm-0 has zero size at this point. When
the device is suspended and resumed, the nodes /dev/mapper/test and
/dev/disk/* are created.

If some program opens a block device before it is created by dmsetup or
lvm, the program is buggy, so dm could just report an error as it used to
do before.

Reported-by: Zdenek Kabelac 
Signed-off-by: Mikulas Patocka 
Fixes: fa247089de99 ("dm: requeue IO if mapping table not yet available")
Signed-off-by: Sasha Levin

dm-integrity: fix a race condition when accessing recalc_sector

2024-09-18T17:24:07+00:00

commit f8e1ca92e35e9041cc0a1bc226ef07a853a22de4 upstream.

There's a race condition when accessing the variable
ic->sb->recalc_sector. The function integrity_recalc writes to this
variable when it makes some progress and the function
dm_integrity_map_continue may read this variable concurrently.

One problem is that on 32-bit architectures the 64-bit variable is not
read and written atomically - it may be possible to read garbage if read
races with write.

Another problem is that memory accesses to this variable are not guarded
with memory barriers.

This commit fixes the race - it moves reading ic->sb->recalc_sector to an
earlier place where we hold &ic->endio_wait.lock.

Signed-off-by: Mikulas Patocka 
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman