A new vulnerability, identified as CVE-2024-27039, has been discovered and resolved in the Linux kernel, specifically relating to the clock functionality (clk) for Hisilicon Hi3559A chips. This post will provide a detailed explanation of the bug, offer code snippets and exploit details as well as links to official references for further information.
Bug Details
In the Linux kernel's clk subsystem, there is an issue with the Hi3559A chip from Hisilicon. When a clk_register() function call fails, the 'p_clk' pointer, which is initially allocated before a particular for loop, might end up pointing to an incorrect location that should not be freed. The issue resides in the 'clk: hisilicon: hi3559a' code, where an erroneous devm_kfree() function call was made.
Exploit Details
An attacker exploiting this vulnerability might cause issues with memory management resulting in unexpected behavior, kernel panics, or crashes. However, to achieve these negative impacts, the attacker needs to have gained control over the kernel or other high-privileged functionalities. Therefore, while the vulnerability presents a risk, actual real-world attacks might be limited.
The Code Fix
To address this vulnerability, the following code changes were made to fix the erroneous devm_kfree() call:
if (ret) {
- devm_kfree(dev, p_clk);
if (i)
for (i--; i >= ; i--)
clk_unregister(p_clk[i].clk_data.hw->clk);
return ERR_PTR(ret);
}
Instead of allowing the 'p_clk' pointer to point to an invalid object and subsequently trying to free the invalid memory address, this code fix ensures that the allocated memory is only released when it is necessary and valid.
Official References
For an in-depth understanding of the vulnerability and the related code changes, the community can refer to the following resources:
Linux kernel Git commit addressing the vulnerability
Hisilicon Hi3559A Documentation
https://www.hisilicon.com/en/products/moblie-and-compute/edge-and-iot-compute/hisilicon-ai-solution
Summary
CVE-2024-27039 is a vulnerability resolved within the Linux kernel clock functionality for the Hisilicon Hi3559A chip. Ensuring proper memory management when a clk_register() call fails, the corrected code eliminates the risk of allocating memory to incorrect locations. While attackers exploiting this vulnerability might cause kernel panics or crashes, wide-scale attacks are unlikely due to the exploitation requirements. The code snippets and official references provided here are aimed to help developers and users understand the issue better and take appropriate steps to secure their systems.
Timeline
Published on: 05/01/2024 13:15:49 UTC
Last modified on: 12/19/2024 08:53:08 UTC