In the world of cybersecurity, the ongoing process of detecting and patching vulnerabilities is critical to ensuring the safety of our systems. Within the Linux kernel, vulnerabilities that have been resolved and assigned a unique identifier are known as Common Vulnerabilities and Exposures (CVE). In this long-read post, we will take a close look at CVE-2023-52457, a vulnerability related to the serial 825 OMAP driver in the Linux kernel. We’ll review the details of the vulnerability, and how it was addressed, including code snippets and links to original references.
The vulnerability at issue is as follows
serial: 825: omap: Don't skip resource freeing if pm_runtime_resume_and_get() failed
When this vulnerability is present in the Linux kernel, it can lead to potential use-after-free issues. The problem lies within the serial 825 OMAP driver in that it could skip the essential step of freeing certain resources if pm_runtime_resume_and_get() failed to execute properly. As a result, this could lead to resource leaks and, in worst-case scenarios, use-after-free issues.
To understand and fix this vulnerability, the developers removed the error return in the .remove() function within the 825 OMAP driver. By doing so, the little helpful error message:
remove callback returned a non-zero value. This will be ignored.
will no longer be emitted by the driver core. Instead, a more useful error message will be displayed, and the process will continue to clean up any remaining resources. This ultimately prevents the use-after-free situation from occurring.
Here is the original reference to the patch, submitted by developer "Lukas Wunner"
serial: 825: omap: Don't skip resource freeing if pm_runtime_resume_and_get() failed - Patchwork
And here is the relevant code snippet that addressed the vulnerability
--- a/drivers/tty/serial/825/825_omap.c
+++ b/drivers/tty/serial/825/825_omap.c
@@ -494,9 +494,10 @@
static int omap825_remove(struct platform_device *pdev)
{
- int ret = pm_runtime_resume_and_get(&pdev->dev);
+ int ret;
struct omap825_priv *priv = platform_get_drvdata(pdev);
+ ret = pm_runtime_resume_and_get(&pdev->dev);
if (ret) {
- dev_err(&pdev->dev, "failed to get device: %d\n", ret);
- return ret;
+ dev_err_probe(&pdev->dev, ret,
+ "failed to get device in remove()\n");
}
In conclusion, addressing vulnerabilities like CVE-2023-52457 in the Linux kernel is essential in maintaining the security posture of Linux-based systems. Thanks to the dedicated efforts of developers and the open-source community, this issue has been resolved and the kernel has been improved as a result. For more information on cybersecurity best practices and addressing vulnerabilities in other software, ensure that you stay up to date on CVEs and patch updates across various platforms and applications.
Timeline
Published on: 02/23/2024 15:15:08 UTC
Last modified on: 04/30/2024 19:28:17 UTC