cbcvebase.
CVE-2024-56672
published 2024-12-27

CVE-2024-56672: 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…

PriorityP431high7CVSS 3.1
AVLACHPRLUINSUCHIHAH
EPSS
0.27%
19.4th percentile
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: 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_thread+0x82a/0xbd0 kthread+0x242/0x2c0 ret_from_fork+0x33/0x70 ret_from_fork_asm+0x1a/0x30 ... Freed by task 1944: kasan_save_track+0x2b/0x70 kasan_save_free_info+0x3c/0x50 __kasan_slab_free+0x33/0x50 kfree+0x10c/0x330 css_free_rwork_fn+0xe6/0xb30 process_scheduled_works+0x71b/0xe20 worker_thread+0x82a/0xbd0 kthread+0x242/0x2c0 ret_from_fork+0x33/0x70 ret_from_fork_asm+0x1a/0x30 Note that the UAF is not easy to trigger as the free path is indirected behind a couple RCU grace periods and a work item execution. I could only trigger it with artifical msleep() injected in blkcg_unpin_online(). Fix it by reading the parent pointer before destroying the blkcg's blkg's.

Affected

30 ranges· showing 25
VendorProductVersion rangeFixed in
debianlinux< linux 6.1.123-1 (bookworm)linux 6.1.123-1 (bookworm)
debianlinux-6.1< linux 6.1.123-1 (bookworm)linux 6.1.123-1 (bookworm)
linuxlinux
linuxlinux>= 4308a434e5e08c78676aa66bc626ef78cbef0883 < 83f5a87ee8caa76a917f59912a74d6811f773c6783f5a87ee8caa76a917f59912a74d6811f773c67
linuxlinux>= 4308a434e5e08c78676aa66bc626ef78cbef0883 < 8a07350fe070017a887433f4d6909433955be5f18a07350fe070017a887433f4d6909433955be5f1
linuxlinux>= 4308a434e5e08c78676aa66bc626ef78cbef0883 < 64afc6fe24c9896c0153e5a199bcea241ecb0d5c64afc6fe24c9896c0153e5a199bcea241ecb0d5c
linuxlinux>= 4308a434e5e08c78676aa66bc626ef78cbef0883 < 5baa28569c924d9a90d036c2aaab79f791fedaf85baa28569c924d9a90d036c2aaab79f791fedaf8
linuxlinux>= 4308a434e5e08c78676aa66bc626ef78cbef0883 < 29d1e06560f0f6179062ac638b4064deb637d1ad29d1e06560f0f6179062ac638b4064deb637d1ad
linuxlinux>= 4308a434e5e08c78676aa66bc626ef78cbef0883 < 86e6ca55b83c575ab0f2e105cf08f98e58d3d7af86e6ca55b83c575ab0f2e105cf08f98e58d3d7af
linuxlinux_kernel
linuxlinux_kernel>= 0 < 5.10.234-15.10.234-1
linuxlinux_kernel>= 0 < 6.1.123-16.1.123-1
linuxlinux_kernel>= 0 < 6.12.6-16.12.6-1
linuxlinux_kernel>= 0 < 6.12.6-16.12.6-1
linuxlinux_kernel>= 0 < 5.15.0-134.1455.15.0-134.145
linuxlinux_kernel>= 0 < 6.8.0-57.596.8.0-57.59
linuxlinux_kernel>= 0 < 4.4.0-268.3024.4.0-268.302
linuxlinux_kernel>= 0 < 4.15.0-237.2494.15.0-237.249
linuxlinux_kernel>= 0 < 5.4.0-212.2325.4.0-212.232
linuxlinux_kernel>= 0 < 5.4.0-211.2315.4.0-211.231
linuxlinux_kernel>= 0 < 5.15.0-138.1485.15.0-138.148
linuxlinux_kernel>= 0 < 5.15.0-135.1465.15.0-135.146
linuxlinux_kernel>= 0 < 6.8.0-57.596.8.0-57.59
linuxlinux_kernel>= 5.7 < 6.1.1216.1.121
linuxlinux_kernel>= 6.2 < 6.6.676.6.67

CVSS provenance

nvdv3.17.0HIGHCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
osv8.8HIGH
vendor_ubuntu8.8HIGH
vendor_msrc7.8HIGH
vendor_debian7.0HIGH
vendor_redhat7.0HIGH
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