CVE-2022-49270
Published: 26 February 2025
Description
In the Linux kernel, the following vulnerability has been resolved: dm: fix use-after-free in dm_cleanup_zoned_dev() dm_cleanup_zoned_dev() uses queue, so it must be called before blk_cleanup_disk() starts its killing: blk_cleanup_disk->blk_cleanup_queue()->kobject_put()->blk_release_queue()-> ->...RCU...->blk_free_queue_rcu()->kmem_cache_free() Otherwise, RCU callback may be executed first and dm_cleanup_zoned_dev() will touch free'd memory: BUG: KASAN: use-after-free in dm_cleanup_zoned_dev+0x33/0xd0 Read of size 8 at addr ffff88805ac6e430 by task dmsetup/681 CPU: 4 PID: 681 Comm: dmsetup Not tainted 5.17.0-rc2+ #6 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x57/0x7d print_address_description.constprop.0+0x1f/0x150 ? dm_cleanup_zoned_dev+0x33/0xd0 kasan_report.cold+0x7f/0x11b ? dm_cleanup_zoned_dev+0x33/0xd0 dm_cleanup_zoned_dev+0x33/0xd0 __dm_destroy+0x26a/0x400 ? dm_blk_ioctl+0x230/0x230 ? up_write+0xd8/0x270 dev_remove+0x156/0x1d0 ctl_ioctl+0x269/0x530 ? table_clear+0x140/0x140 ? lock_release+0xb2/0x750 ? remove_all+0x40/0x40 ? rcu_read_lock_sched_held+0x12/0x70 ? lock_downgrade+0x3c0/0x3c0 ? rcu_read_lock_sched_held+0x12/0x70 dm_ctl_ioctl+0xa/0x10 __x64_sys_ioctl+0xb9/0xf0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fb6dfa95c27
Security Summary
CVE-2022-49270 is a use-after-free vulnerability in the Linux kernel's Device Mapper (dm) subsystem, specifically within the dm_cleanup_zoned_dev() function. This issue arises because dm_cleanup_zoned_dev() accesses the queue after blk_cleanup_disk() has initiated its cleanup process, which can lead to the queue being freed via an RCU callback before the dm function completes. The vulnerability was observed in kernel version 5.17.0-rc2 and affects dm operations on zoned devices.
A local attacker with low privileges (PR:L) can exploit this vulnerability with low attack complexity (AC:L) and no user interaction (UI:N) by invoking ioctls, such as those used by the dmsetup utility during device removal (e.g., dev_remove). This triggers the use-after-free, as demonstrated in a KASAN-reported crash where dm_cleanup_zoned_dev() reads from freed memory at address ffff88805ac6e430. Exploitation yields high impacts on confidentiality, integrity, and availability (C:H/I:H/A:H), with an overall CVSS v3.1 score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) and CWE-416 classification.
Kernel patches in the stable repository address the issue by ensuring dm_cleanup_zoned_dev() is called before blk_cleanup_disk() to avoid accessing freed queue memory. Relevant commits include 0987f00a76a17aa7213da492c00ed9e5a6210c73, 43a043aed964659bc69ef81f266912b73c80d837, 588b7f5df0cb64f281290c7672470c006abe7160, and fdfe414ca28ddfd562c233fb27385cf820de03e8, available via git.kernel.org/stable. Security practitioners should update affected Linux kernels accordingly.
Details
- CWE(s)