Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
misc/libmasm/module: Fix two use after free in ibmasm_init_one
In ibmasm_init_one, it calls ibmasm_init_remote_input_dev(). Inside ibmasm_init_remote_input_dev, mouse_dev and keybd_dev are allocated by input_allocate_device(), and assigned to sp->remote.mouse_dev and sp->remote.keybd_dev respectively.
In the err_free_devices error branch of ibmasm_init_one, mouse_dev and keybd_dev are freed by input_free_device(), and return error. Then the execution runs into error_send_message error branch of ibmasm_init_one, where ibmasm_free_remote_input_dev(sp) is called to unregister the freed sp->remote.mouse_dev and sp->remote.keybd_dev.
My patch add a “error_init_remote” label to handle the error of ibmasm_init_remote_input_dev(), to avoid the uaf bugs.
Details
- Affected product:
- 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 , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS
- Affected packages:
- kernel-uek @ 5.4.17 (+16 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Ubuntu 16.04 AWS HWE ESM | Will Not Fix | — |
| Ubuntu 16.04 Azure ESM | Will Not Fix | — |
| Ubuntu 16.04 GCP ESM | Will Not Fix | — |
| Ubuntu 16.04 HWE ESM | Will Not Fix | — |
| Ubuntu 18.04 | Will Not Fix | — |
| Ubuntu 18.04 AWS | Will Not Fix | — |
| 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 | Will Not Fix | — |
| Ubuntu 20.04 AWS | Will Not Fix | — |