The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 3534e5a5ed2997ca1b00f44a0378a075bd05e8a3 Mon Sep 17 00:00:00 2001 From: Luo Meng luomeng12@huawei.com Date: Thu, 14 Jul 2022 19:28:25 +0800 Subject: [PATCH] dm thin: fix use-after-free crash in dm_sm_register_threshold_callback
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@vger.kernel.org Reported-by: Hulk Robot hulkci@huawei.com Signed-off-by: Luo Meng luomeng12@huawei.com Signed-off-by: Mike Snitzer snitzer@kernel.org
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c index 2db7030aba00..a27395c8621f 100644 --- a/drivers/md/dm-thin-metadata.c +++ b/drivers/md/dm-thin-metadata.c @@ -2045,10 +2045,13 @@ 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 84c083f76673..e76c96c760a9 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -3375,8 +3375,10 @@ 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);