CVE-2024-56672

/// Technical description

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

blk-cgroup: Fix UAF in blkcg_unpin_online()

blkcg_unpin_online() walks up the blkcg hierarchy putting the online pin. To

walk up, it uses blkcg_parent(blkcg) but it was calling that after

blkcg_destroy_blkgs(blkcg) which could free the blkcg, leading to the

following UAF:

==================================================================

BUG: KASAN: slab-use-after-free in blkcg_unpin_online+0x15a/0x270

Read of size 8 at addr ffff8881057678c0 by task kworker/9:1/117

CPU: 9 UID: 0 PID: 117 Comm: kworker/9:1 Not tainted 6.13.0-rc1-work-00182-gb8f52214c61a-dirty #48

Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS unknown 02/02/2022

Workqueue: cgwb_release cgwb_release_workfn

Call Trace:

<TASK>

dump_stack_lvl+0x27/0x80

print_report+0x151/0x710

kasan_report+0xc0/0x100

blkcg_unpin_online+0x15a/0x270

cgwb_release_workfn+0x194/0x480

process_scheduled_works+0x71b/0xe20

worker

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References