CVE-2022-50092

In the Linux kernel, the following vulnerability has been resolved:

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: 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.

Affected Software

References

• https://git.kernel.org/stable/c/05cef0999b3208b5a6ede1bfac855139e4de55ef
• https://git.kernel.org/stable/c/1a199fa9217d28511ff88529238fd9980ea64cf3
• https://git.kernel.org/stable/c/3534e5a5ed2997ca1b00f44a0378a075bd05e8a3
• https://git.kernel.org/stable/c/5e2cf705155a1514be3c96ea664a9cd356998ee7
• https://git.kernel.org/stable/c/e4dbe24f4bfd8377e7ba79fdcdb7c4d6eb1c6790
• https://git.kernel.org/stable/c/f83131a3071a0b61a4d7dca70f95adb3ffad920e