Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: blk-cgroup: skip dying blkg in blkcg_activate_policy() When switching IO schedulers on a block device, blkcg_activate_policy() can race with concurrent blkcg deletion, leading to a use-after-free in rcu_accelerate_cbs. T1: T2: blkg_destroy kill(&blkg->refcnt) // blkg->refcnt=1->0 blkg_release // call_rcu(__blkg_release) ... blkg_free_workfn ->pd_free_fn(pd) elv_iosched_store elevator_switch ... iterate blkg list blkg_get(blkg) // blkg->refcnt=0->1 list_del_init(&blkg->q_node) blkg_put(pinned_blkg) // blkg->refcnt=1->0 blkg_release // call_rcu again rcu_accelerate_cbs // uaf Fix this by checking hlist_unhashed(&blkg->blkcg_node) before getting a reference to the blkg. This is the same check used in blkg_destroy() to detect if a blkg has already been destroyed. If the blkg is already unhashed, skip processing it since it's being destroyed.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 81c1188905f88b77743d1fdeeedfc8cb7b67787d before b5dae1cd0d8368b4338430ff93403df67f0b8bcc; affected bfe46d2efe46c5c952f982e2ca94fe2ec5e58e2a before 083b58373463a6e5ee60ecb135269348f68ad7df; affected f1c006f1c6850c14040f8337753a63119bba39b9 before 1a267295b1ea6a6477963f3fda84adfecd48fcad; affected f1c006f1c6850c14040f8337753a63119bba39b9 before 7337d012ca3fc3a6a2d1c8e2a19c6d97c38b410d; affected f1c006f1c6850c14040f8337753a63119bba39b9 before 3d8c3da95c75a4d312e272fc7b4076dd3ba9115c; affected f1c006f1c6850c14040f8337753a63119bba39b9 before d8c872901e6459339374e9eea80aa919176c2ccd; affected f1c006f1c6850c14040f8337753a63119bba39b9 before 5e9220389920f33b6a804d50c548cd0cd1b04634; affected 6.1.16 before 6.1.17; affected 6.2.3 before 6.2.4 |
| Linux / Linux | affected 6.3; unaffected 0 before 6.3; unaffected 6.1.17 through 6.1.*; unaffected 6.2.4 through 6.2.*; unaffected 6.6.157 through 6.6.*; unaffected 6.12.110 through 6.12.*; unaffected 6.18.52 through 6.18.*; unaffected 7.2.6 through 7.2.*; unaffected 7.3 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/b5dae1cd0d8368b4338430ff93403df67f0b8bcc
- https://git.kernel.org/stable/c/083b58373463a6e5ee60ecb135269348f68ad7df
- https://git.kernel.org/stable/c/1a267295b1ea6a6477963f3fda84adfecd48fcad
- https://git.kernel.org/stable/c/7337d012ca3fc3a6a2d1c8e2a19c6d97c38b410d
- https://git.kernel.org/stable/c/3d8c3da95c75a4d312e272fc7b4076dd3ba9115c
- https://git.kernel.org/stable/c/d8c872901e6459339374e9eea80aa919176c2ccd
- https://git.kernel.org/stable/c/5e9220389920f33b6a804d50c548cd0cd1b04634