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author | Luo Meng <luomeng12@huawei.com> | 2022-11-29 10:48:47 +0800 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-01-18 11:30:42 +0100 |
commit | e8b8e0d2bbf7d1172c4f435621418e29ee408d46 (patch) | |
tree | 6c114cebdb96204b4c45e5455987dcf946495c10 /drivers/md/dm-thin.c | |
parent | 3db757ffdd87ed8d7118b2250236a496502a660f (diff) | |
download | linux-stable-e8b8e0d2bbf7d1172c4f435621418e29ee408d46.tar.gz linux-stable-e8b8e0d2bbf7d1172c4f435621418e29ee408d46.tar.bz2 linux-stable-e8b8e0d2bbf7d1172c4f435621418e29ee408d46.zip |
dm thin: Fix UAF in run_timer_softirq()
commit 88430ebcbc0ec637b710b947738839848c20feff upstream.
When dm_resume() and dm_destroy() are concurrent, it will
lead to UAF, as follows:
BUG: KASAN: use-after-free in __run_timers+0x173/0x710
Write of size 8 at addr ffff88816d9490f0 by task swapper/0/0
<snip>
Call Trace:
<IRQ>
dump_stack_lvl+0x73/0x9f
print_report.cold+0x132/0xaa2
_raw_spin_lock_irqsave+0xcd/0x160
__run_timers+0x173/0x710
kasan_report+0xad/0x110
__run_timers+0x173/0x710
__asan_store8+0x9c/0x140
__run_timers+0x173/0x710
call_timer_fn+0x310/0x310
pvclock_clocksource_read+0xfa/0x250
kvm_clock_read+0x2c/0x70
kvm_clock_get_cycles+0xd/0x20
ktime_get+0x5c/0x110
lapic_next_event+0x38/0x50
clockevents_program_event+0xf1/0x1e0
run_timer_softirq+0x49/0x90
__do_softirq+0x16e/0x62c
__irq_exit_rcu+0x1fa/0x270
irq_exit_rcu+0x12/0x20
sysvec_apic_timer_interrupt+0x8e/0xc0
One of the concurrency UAF can be shown as below:
use free
do_resume |
__find_device_hash_cell |
dm_get |
atomic_inc(&md->holders) |
| dm_destroy
| __dm_destroy
| if (!dm_suspended_md(md))
| atomic_read(&md->holders)
| msleep(1)
dm_resume |
__dm_resume |
dm_table_resume_targets |
pool_resume |
do_waker #add delay work |
dm_put |
atomic_dec(&md->holders) |
| dm_table_destroy
| pool_dtr
| __pool_dec
| __pool_destroy
| destroy_workqueue
| kfree(pool) # free pool
time out
__do_softirq
run_timer_softirq # pool has already been freed
This can be easily reproduced using:
1. create thin-pool
2. dmsetup suspend pool
3. dmsetup resume pool
4. dmsetup remove_all # Concurrent with 3
The root cause of this UAF bug is that dm_resume() adds timer after
dm_destroy() skips cancelling the timer because of suspend status.
After timeout, it will call run_timer_softirq(), however pool has
already been freed. The concurrency UAF bug will happen.
Therefore, cancelling timer again in __pool_destroy().
Cc: stable@vger.kernel.org
Fixes: 991d9fa02da0d ("dm: add thin provisioning target")
Signed-off-by: Luo Meng <luomeng12@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/md/dm-thin.c')
-rw-r--r-- | drivers/md/dm-thin.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index 435a2ee4a392..1916becc20e0 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -2921,6 +2921,8 @@ static void __pool_destroy(struct pool *pool) dm_bio_prison_destroy(pool->prison); dm_kcopyd_client_destroy(pool->copier); + cancel_delayed_work_sync(&pool->waker); + cancel_delayed_work_sync(&pool->no_space_timeout); if (pool->wq) destroy_workqueue(pool->wq); |