This is a note to let you know that I've just added the patch titled
dm thin: fix use-after-free crash in dm_sm_register_threshold_callback
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dm-thin-fix-use-after-free-crash-in-dm_sm_register_t.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 875865ffbe115bafceb09867b999cfe17a0dc5df
Author: Luo Meng <luomeng12@xxxxxxxxxx>
Date: Thu Jul 14 19:28:25 2022 +0800
dm thin: fix use-after-free crash in dm_sm_register_threshold_callback
[ Upstream commit 3534e5a5ed2997ca1b00f44a0378a075bd05e8a3 ]
Fault inject on pool metadata device reports:
BUG: KASAN: use-after-free in dm_pool_register_metadata_threshold+0x40/0x80
Read of size 8 at addr ffff8881b9d50068 by task dmsetup/950
CPU: 7 PID: 950 Comm: dmsetup Tainted: G W 5.19.0-rc6 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x34/0x44
print_address_description.constprop.0.cold+0xeb/0x3f4
kasan_report.cold+0xe6/0x147
dm_pool_register_metadata_threshold+0x40/0x80
pool_ctr+0xa0a/0x1150
dm_table_add_target+0x2c8/0x640
table_load+0x1fd/0x430
ctl_ioctl+0x2c4/0x5a0
dm_ctl_ioctl+0xa/0x10
__x64_sys_ioctl+0xb3/0xd0
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
This can be easily reproduced using:
echo offline > /sys/block/sda/device/state
dd if=/dev/zero of=/dev/mapper/thin bs=4k count=10
dmsetup load pool --table "0 20971520 thin-pool /dev/sda /dev/sdb 128 0 0"
If a metadata commit fails, the transaction will be aborted and the
metadata space maps will be destroyed. If a DM table reload then
happens for this failed thin-pool, a use-after-free will occur in
dm_sm_register_threshold_callback (called from
dm_pool_register_metadata_threshold).
Fix this by in dm_pool_register_metadata_threshold() by returning the
-EINVAL error if the thin-pool is in fail mode. Also fail pool_ctr()
with a new error message: "Error registering metadata threshold".
Fixes: ac8c3f3df65e4 ("dm thin: generate event when metadata threshold passed")
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
Signed-off-by: Luo Meng <luomeng12@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index c88ed14d49e6..0ada99572b68 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -2073,10 +2073,13 @@ int dm_pool_register_metadata_threshold(struct dm_pool_metadata *pmd,
dm_sm_threshold_fn fn,
void *context)
{
- int r;
+ int r = -EINVAL;
pmd_write_lock_in_core(pmd);
- r = dm_sm_register_threshold_callback(pmd->metadata_sm, threshold, fn, context);
+ if (!pmd->fail_io) {
+ r = dm_sm_register_threshold_callback(pmd->metadata_sm,
+ threshold, fn, context);
+ }
pmd_write_unlock(pmd);
return r;
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 4c67b77c23c1..0a85e4cd607c 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -3401,8 +3401,10 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
calc_metadata_threshold(pt),
metadata_low_callback,
pool);
- if (r)
+ if (r) {
+ ti->error = "Error registering metadata threshold";
goto out_flags_changed;
+ }
dm_pool_register_pre_commit_callback(pool->pmd,
metadata_pre_commit_callback, pool);
