CVE-2024-53110: Critical Vulnerability in Linux Kernel Fixed, vp_vdpa Module Patched to Prevent Null-Terminated Error and Undefined Memory Access

A major vulnerability, known as CVE-2024-53110, has been discovered and resolved in the Linux kernel involving the vp_vdpa module. This Linux kernel vulnerability is particularly concerning, as it can cause undefined memory access, potentially allowing malicious actors to exploit it and compromise systems. In this long read, we will discuss the vulnerability in detail, including the code snippets, original references, and exploit details, as well as the fix implemented to safeguard systems against this critical issue.

CVE-2024-53110: Vulnerability Details

The vulnerability in question is related to the vp_vdpa module, which is responsible for managing Virtio devices. The issue arises because the id_table array used by the vdpa_mgmtdev_get_classes() function is not null-terminated. Consequently, this function may iterate over the array multiple times, leading to undefined memory access.

Original reference to the vulnerability can be found in these two sources

- Linux Kernel Mailing List
- Git.kernel.org

The initial problematic code snippet in the vp_vdpa module of the Linux kernel can be seen below

static const struct virtio_device_id id_table[] = {
    { VIRTIO_ID_VHOST, VIRTIO_DEV_ANY_ID },
    {  },
};

static int vp_vdpa_probe(struct virtio_device *vdev)
{
    //... omitted for brevity ...

    err = vdpa_mgmtdev_get_classes(pdev, &classes);
    if (err)
        goto out;

    //... omitted for brevity ...
}

In the snippet, the id_table array is not properly null-terminated, which can lead to issues related to undefined memory access while the vdpa_mgmtdev_get_classes() function iterates through the array.

## Exploring the Exploitation Details

A malicious actor can potentially exploit the vulnerability to gain unauthorized access to constrained memory regions of the system, leading to adverse consequences such as system crashes, data corruption, or remote code execution, given the right circumstances. The exact details of the exploitation, however, will depend on a variety of factors, such as the Linux distribution, kernel version, and specific configurations of the target system.

## Patch and Solution

To address this severe vulnerability, the Linux kernel developers have introduced an essential patch that allocates one extra virtio_device_id to act as a null terminator within the id_table array. This change ensures that the vdpa_mgmtdev_get_classes() function does not iterate over the array multiple times, preventing any access to undefined memory. The patch can be observed in the following code snippet:

static const struct virtio_device_id id_table[] = {
    { VIRTIO_ID_VHOST, VIRTIO_DEV_ANY_ID },
    {  },
    {  }, // Added null terminator
};

static int vp_vdpa_probe(struct virtio_device *vdev)
{
    //... omitted for brevity ...

    err = vdpa_mgmtdev_get_classes(pdev, &classes);
    if (err)
        goto out;

    //... omitted for brevity ...
}

Conclusion

CVE-2024-53110 highlights the importance of proper array management and the potential consequences of null-terminated errors. Thanks to the quick response by the Linux kernel development community, systems can now be patched to prevent exploitation of this critical vulnerability. It is essential for system administrators and users to regularly update their kernel, ensuring that they are protected against security vulnerabilities like CVE-2024-53110.

Timeline

Published on: 12/02/2024 14:15:11 UTC
Last modified on: 12/19/2024 09:39:26 UTC