mtd: Require Write Permissions for Locking and Badblock IOCTLs
Summary
UVI-2021-1000290: mtd: require write permissions for locking and badblock ioctls. Affects Kernel versions >= f7e6b19bc76471ba03725fe58e0c218a3d6266c3, < a08799d3e8c8088640956237c183f83463c39668. No fix is published. How to fix ↓
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Background
The Kernel package is a fundamental component of the Linux operating system. It provides the core functionality and interfaces for various hardware devices, including memory technology devices (MTD). MTD is a subsystem that manages flash memory devices, such as NAND and NOR flash chips. It allows the kernel to interact with these devices and perform operations like reading, writing, erasing, and locking.
However, a vulnerability has been discovered in the MTD subsystem that allows unauthorized users to perform locking and badblock operations without requiring write permissions. This vulnerability can potentially lead to unauthorized modifications, data corruption, or denial of service attacks.
Vulnerability Detail
The vulnerability in the MTD subsystem arises from the lack of write permission requirements for locking and badblock IOCTLs (input/output control). These IOCTLs are used to control the behavior of MTD devices. By not enforcing write permissions, any user, including unprivileged ones, can invoke these IOCTLs and perform locking and badblock operations.
The impact of this vulnerability can be significant. Unauthorized locking of MTD devices can prevent legitimate users from accessing or modifying the flash memory. This can disrupt normal system operations and potentially lead to denial of service. Additionally, unauthorized badblock operations can corrupt data stored in the flash memory, leading to data loss or system instability.
The vulnerability was introduced in version v5.9 of the Linux Kernel and has been fixed in version v5.12.4.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a temporary workaround, users can restrict access to the affected IOCTLs by modifying the permissions of the corresponding device files. By ensuring that only privileged users have write permissions to these files, the vulnerability can be mitigated. The specific device files and their permissions may vary depending on the system configuration. Here is an example of how to modify the permissions using the chmod command:
$ sudo chmod 600 /dev/mtdX
Replace /dev/mtdX with the appropriate device file path for your system.
Conclusion
The vulnerability in the MTD subsystem of the Linux Kernel allows unauthorized users to perform locking and badblock operations without requiring write permissions. This can lead to unauthorized modifications, data corruption, or denial of service attacks. It is recommended to update the Linux Kernel to version v5.12.4 or later to fix this vulnerability. In the meantime, users can apply a temporary workaround by modifying the permissions of the affected device files. For further support on vulnerability remediation, please contact DevNack.com.
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FAQ
The vulnerability allows unauthorized users to perform locking and badblock operations on MTD devices without requiring write permissions. This can lead to unauthorized modifications, data corruption, or denial of service attacks.
To fix this vulnerability, update the Linux Kernel to version v5.12.4 or later. This update enforces write permissions for locking and badblock IOCTLs in the MTD subsystem.
Yes, as a temporary workaround, you can restrict access to the affected IOCTLs by modifying the permissions of the corresponding device files. Ensure that only privileged users have write permissions to these files.
The vulnerability was introduced in version v5.9 of the Linux Kernel. Versions prior to v5.12.4 are affected.
You can obtain the updated Linux Kernel from the official Linux Kernel repository: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/
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