In the world of cybersecurity, it is crucial to stay up-to-date on vulnerabilities and fixes. One such vulnerability that has been recently identified and resolved is present in the Linux kernel. In this post, we look at the details of this vulnerability - CVE-2024-53076 - and its impact, as well as the fix implemented to address the issue. We'll also provide code snippets and links to the original references for those interested in diving deeper into the technical details.

The Vulnerability: CVE-2024-53076

The vulnerability pertains to a memory leak present in the Linux kernel in the iio: gts-helper module. Specifically, it involves the iio_gts_build_avail_scale_table() function. The issue arises when the kcalloc() function fails in the for loop, which causes err_free_out to not call kfree() as intended. As a result, memory leaks occur when per_time_scales[] and per_time_gains[] are not effectively freed.

Here's the affected code snippet (prior to applying the fix)

for (i = ; i < num_scales; i++) {
    per_time_scales[i] = kcalloc(num_gains, sizeof(*per_time_scales[i]),
                                  GFP_KERNEL);
    per_time_gains[i] = kcalloc(num_gains, sizeof(*per_time_gains[i]),
                                GFP_KERNEL);

    if (!per_time_scales[i] || !per_time_gains[i])
        goto err_free_out;
}

The vulnerability can have a significant impact as it leads to memory leaks in the Linux kernel, which can hamper system stability and performance.

The Fix

To resolve the vulnerability, a simple conditional check is added to verify if i >= . This ensures that when the error occurs and i is reduced to , kfree() is appropriately called to free up the memory for per_time_scales[] and per_time_gains[]. This, in turn, resolves the memory leak issue.

Here's the fixed code snippet

for (i = ; i < num_scales; i++) {
    per_time_scales[i] = kcalloc(num_gains, sizeof(*per_time_scales[i]),
                                  GFP_KERNEL);
    per_time_gains[i] = kcalloc(num_gains, sizeof(*per_time_gains[i]),
                                GFP_KERNEL);

    if (!per_time_scales[i] || !per_time_gains[i])
        goto err_free_out;
}

err_free_out:
    if (i >= ) {
        for (; i >= ; i--) {
            kfree(per_time_scales[i]);
            kfree(per_time_gains[i]);
        }
    }

Original References

To learn more about this vulnerability and explore its technical details, refer to the following resources:

- Linux kernel patch for the vulnerability: Patchwork - LKML Archive
- Linux kernel source: Linux Kernel Web Repository

Exploit Details

As of now, there are no known instances of this vulnerability being exploited in the wild. However, it is essential to apply the latest security patches to your Linux systems to protect against potential attacks. Keeping your systems updated and monitoring for any unusual activities can help minimize the risk of cyber threats.

Conclusion

This post has highlighted the details of a recently resolved memory leak vulnerability in the Linux kernel, CVE-2024-53076. With the addition of a simple conditional check in the code, this potential security issue has been mitigated. As always, it is crucial to stay informed about cybersecurity developments and ensure that systems are up-to-date with the latest patches and security measures. The resources provided above offer great insight into the technical aspects of this vulnerability, and it is highly recommended for those interested in learning more.

Timeline

Published on: 11/19/2024 18:15:27 UTC
Last modified on: 11/22/2024 22:24:24 UTC