Introduction:
The Linux kernel is an essential part of any Linux-based operating system, and it is constantly being updated and improved by developers worldwide. From time to time, bugs and vulnerabilities are discovered and reported in the kernel, which could potentially lead to undesirable system behavior, crashes, or even security breaches.

In this blog post, we will take a close look at a recent vulnerability that has been resolved in the Linux kernel under the CVE-2023-52460 identifier. The vulnerability, which falls under the drm/amd/display component, has been addressed to fix a NULL pointer dereference issue that could potentially occur during the system's hibernation sequence.

CVE-2023-52460 Vulnerability Details

Exploit: drm/amd/display Fix NULL pointer dereference at hibernate

In the context of this vulnerability, the Linux kernel's drm/amd/display component addresses a situation where a NULL pointer dereference may occur during the system hibernation process. This could lead to a crash or unexpected system behavior, which would be particularly problematic for systems operating in environments where prolonged uptime and reliable operation are crucial.

In simple terms, a pointer is a variable used in programming to store the memory address of a data object. A NULL pointer points to nothing, and dereferencing a NULL pointer (i.e., attempting to read or write data through it) usually results in a crash. In this case, the crash is caused by the kernel attempting to access a data object via a pointer that has not been properly initialized.

The source context might not have a clock manager (clk_mgr) during the hibernation process.

The developers resolved the bug by ensuring that the appropriate measures are taken to avoid dereferencing a NULL pointer in the affected code.

Code Snippet:

The following code snippet, taken from the drm/amd/display component, demonstrates the fix that was implemented:

if (dc->clk_mgr && dc->clk_mgr->
dc->dml.dml_get_status() == DML_PROJECT_RAVEN2)

In the fixed version, the developers added a conditional check (if statement) to ensure that the pointer (dc->clk_mgr) is not NULL before using it to look for DML2 (Data Model for Long Lived Systems) support during the hibernate sequence.

Original References

The CVE-2023-52460 issue was reported and patched by AMD developers. More details about the vulnerability, as well as the patch that has been submitted for integration into the mainline Linux kernel, can be found at the following links:

1. Kernel git commit
2. Linux kernel mailing list

Conclusion

The CVE-2023-52460 vulnerability, which resulted in a NULL pointer dereference in the Linux kernel's drm/amd/display component during the hibernation process, has been effectively resolved by the developers. The fix ensures that the affected code checks for a valid pointer before accessing memory. This is a prime example of the ongoing commitment to maintain and improve the stability, performance, and security of the Linux kernel for millions of users worldwide. To ensure that your system remains secure and up-to-date, consider updating your kernel to the latest version as soon as possible.

Timeline

Published on: 02/23/2024 15:15:08 UTC
Last modified on: 04/30/2024 19:16:12 UTC