CVE-2024-52332 - Fix to Potential Invalid Memory Access in the Linux Kernel's igb_init_module()

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In a recent update to the Linux kernel, a crucial vulnerability has been addressed that pertains specifically to the Intel Gigabit Ethernet Driver, commonly known as igb. With the existence of this vulnerability, it was possible for the kernel to experience invalid memory access, resulting in unexpected behavior and potential security risks. In this long read post, we will explore the details surrounding CVE-2024-52332, including the changes implemented to address this vulnerability, the code snippets that highlight key aspects, and original references for further investigation.

Exploit Details

The primary issue CVE-2024-52332 aimed to resolve involves a potential invalid memory access within the igb_init_module() function. Specifically, the pci_register_driver() function may experience a failure while attempting to register the driver. When this occurs, the dca_notifier is expected to unregister, preventing further failures. However, prior to the fix, the dca_notifier would not always be unregistered, leading to potential invalid memory access if the igb driver installation failed.

Code Snippet

The original code within the igb_init_module() function, lacking the proper handling of dca_notifier, looked like this:

static int __init igb_init_module(void)
{
	int ret;

	pr_info("Intel(R) Gigabit Ethernet Network Driver - version %s\n",
		igb_driver_version);

	ret = pci_register_driver(&igb_driver);
	if (ret)
		pr_err("igb: Unable to register PCI driver, Error: %d\n", ret);

	return ret;
}

To resolve this issue, the updated code for the igb_init_module() function includes an additional check for the return status of pci_register_driver(), ensuring that the dca_notifier is cleaned up and unregistered correctly. Here is the modified code snippet with the added condition:

static int __init igb_init_module(void)
{
	int ret;

	pr_info("Intel(R) Gigabit Ethernet Network Driver - version %s\n",
		igb_driver_version);

	ret = pci_register_driver(&igb_driver);
	if (ret) {
		pr_err("igb: Unable to register PCI driver, Error: %d\n", ret);
		dca_unregister_notify(&igb_driver.drv.driver);
	}

	return ret;
}

Original References

- To understand the complete context of CVE-2024-52332, you can view the original git commit diff on the Linux kernel Git repository.

- Further details regarding the Linux kernel igb driver, its features, and functionality, can be gleaned from the Intel Ethernet Drivers and Utilities project on SourceForge.

- If you're interested in learning more about Direct Cache Access (DCA) which the dca_notifier is related to, read through the documentation provided by Intel on I/O Acceleration Technology.

Conclusion

The Linux kernel developers have diligently addressed the vulnerability regarding potential invalid memory access in the igb_init_module(), as detailed in CVE-2024-52332. By ensuring the proper cleanup and unregistering of the dca_notifier in the event of a pci_register_driver() failure, kernel users can be confident that this particular security risk has been effectively mitigated.

Timeline

Published on: 01/11/2025 13:15:25 UTC
Last modified on: 01/20/2025 06:19:35 UTC