Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
gfs2: Fix potential glock use-after-free on unmount
When a DLM lockspace is released and there ares still locks in that lockspace, DLM will unlock those locks automatically. Commit fb6791d100d1b started exploiting this behavior to speed up filesystem unmount: gfs2 would simply free glocks it didn’t want to unlock and then release the lockspace. This didn’t take the bast callbacks for asynchronous lock contention notifications into account, which remain active until until a lock is unlocked or its lockspace is released.
To prevent those callbacks from accessing deallocated objects, put the glocks that should not be unlocked on the sd_dead_glocks list, release the lockspace, and only then free those glocks.
As an additional measure, ignore unexpected ast and bast callbacks if the receiving glock is dead.
Details
- Affected product:
- AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 6 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 6 ELS , CloudLinux 7 ELS , Debian 10 ELS , Oracle Linux 6 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
- Affected packages:
- kernel @ 5.14.0 (+18 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| AlmaLinux 8 | Released |
43 kernels
|
| AlmaLinux 9 | Released |
30 kernels
|
| CentOS 7 ELS | Ready For Release | — |
| CentOS 8 | Released |
33 kernels
|
| CloudLinux OS 7h | Released |
60 kernels
|
| CloudLinux OS 8 | Released |
56 kernels
|
| Oracle Linux 8 | Released |
68 kernels
|
| Oracle Linux 9 | Released |
36 kernels
|
| Proxmox VE 7 5.15 | Released |
47 kernels
|
| RHEL 8 | Released |
64 kernels
|
| RHEL8 EUS 8.6 | Released |
24 kernels
|
| RHEL 9 | Released |
30 kernels
|
| Rocky Linux 8 | Released |
38 kernels
|
| Rocky Linux 9 | Released |
30 kernels
|
| Ubuntu 14.04 HWE ESM | Will Not Fix | — |
| Ubuntu 16.04 AWS ESM | Will Not Fix | — |
| Ubuntu 16.04 AWS HWE ESM | Will Not Fix | — |
| Ubuntu 16.04 Azure ESM | Will Not Fix | — |
| Ubuntu 16.04 ESM | Will Not Fix | — |
| Ubuntu 16.04 GCP ESM | Will Not Fix | — |
| Ubuntu 16.04 HWE ESM | Will Not Fix | — |
| Ubuntu 18.04 | Planned | — |
| Ubuntu 18.04 AWS | Planned | — |
| Ubuntu 18.04 AWS Focal | Will Not Fix | — |
| Ubuntu 18.04 Azure Focal | Will Not Fix | — |
| Ubuntu 18.04 HWE Focal | Will Not Fix | — |
| Ubuntu 20.04 | Ready For Release | — |
| Ubuntu 20.04 AWS | Ready For Release | — |
| Ubuntu 20.04 Azure | Ready For Release | — |
| Ubuntu 20.04 GCP | Ready For Release | — |
| Ubuntu 20.04 HWE AWS | Released |
46 kernels
|
| Ubuntu 20.04 HWE Azure | Released |
29 kernels
|
| Ubuntu 22.04 | Released |
59 kernels
|
| Ubuntu 22.04 AWS | Released |
53 kernels
|
| Ubuntu 22.04 Azure | Released |
49 kernels
|
| Ubuntu 24.04 | Ready For Release | — |