CVE-2023-52439 | Date: (C)2024-02-21 (M)2024-05-10 |
In the Linux kernel, the following vulnerability has been resolved:
uio: Fix use-after-free in uio_open
core-1 core-2
-------------------------------------------------------
uio_unregister_device uio_open
idev = idr_find()
device_unregister(&idev->dev)
put_device(&idev->dev)
uio_device_release
get_device(&idev->dev)
kfree(idev)
uio_free_minor(minor)
uio_release
put_device(&idev->dev)
kfree(idev)
-------------------------------------------------------
In the core-1 uio_unregister_device(), the device_unregister will kfree
idev when the idev->dev kobject ref is 1. But after core-1
device_unregister, put_device and before doing kfree, the core-2 may
get_device. Then:
1. After core-1 kfree idev, the core-2 will do use-after-free for idev.
2. When core-2 do uio_release and put_device, the idev will be double
freed.
To address this issue, we can get idev atomic & inc idev reference with
minor_lock.
CVSS Score and Metrics +CVSS Score and Metrics -CVSS V3 Severity: | CVSS V2 Severity: |
CVSS Score : 7.8 | CVSS Score : |
Exploit Score: 1.8 | Exploit Score: |
Impact Score: 5.9 | Impact Score: |
|
CVSS V3 Metrics: | CVSS V2 Metrics: |
Attack Vector: LOCAL | Access Vector: |
Attack Complexity: LOW | Access Complexity: |
Privileges Required: LOW | Authentication: |
User Interaction: NONE | Confidentiality: |
Scope: UNCHANGED | Integrity: |
Confidentiality: HIGH | Availability: |
Integrity: HIGH | |
Availability: HIGH | |
| |