In the Linux kernel, a critical vulnerability has been identified and fixed in the vsock/virtio module. The vulnerability, assigned as CVE-2024-50264, is related to the initialization of a dangling pointer occurring in the vsk->trans field. This vulnerability may lead to a Use-After-Free condition if exploited. We explain the nature of this vulnerability and provide the necessary code snippet that addresses the issue. Additionally, we present links to the original references and provide an overview of the potential exploit details.
Code Snippet Fix
To resolve the vulnerability, a simple modification is needed in the vsock/virtio module. This change involves initializing the vsk->trans field to NULL in the relevant function:
static int virtio_transport_release(struct vsock_sock *vsk)
{
/* ... */
/* Initialize 'vsk->trans' to NULL to avoid the Use-After-Free*/
vsk->trans = NULL;
}
Dangling Pointer Vulnerability Details
A dangling pointer is a pointer that references a memory location that has been deallocated, rendering the reference invalid. Attempting to access the object or memory block can lead to unpredictable behavior and crashes.
In the Linux kernel, during loopback communication (where data is sent back to the sender), a dangling pointer can be created in the vsk->trans field, which is part of the vsock socket structure. If not initialized to NULL, this dangling pointer could provide the attacker with an opportunity to exploit a Use-After-Free (UAF) condition.
Use-After-Free vulnerabilities are memory corruption issues in software programs that occur when memory is used after it has been released. These vulnerabilities can lead to unauthorized memory access, data corruption or disclosure, denial of service, or even arbitrary code execution.
Original References
The Linux kernel developers have acknowledged the vulnerability and have patched it in the current distribution. You can find the relevant patch and mailing list discussion in the following links:
Linux Kernel Git Commit:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=528cd34da
LKML (Linux Kernel Mailing List)
https://lkml.org/lkml/2024/7/18/404
Exploit Details
At this point in time, there are no known exploits in the wild that take advantage of this vulnerability. However, it is always best to keep your systems updated to avoid potential security breaches. Applying the patch provided by the Linux kernel developers to the vsock/virtio module can mitigate this vulnerability and protect your Linux systems from potential threats.
Conclusion
The CVE-2024-50264 vulnerability found in the Linux kernel's vsock/virtio module represents a potential risk to Linux systems. By properly initializing the vsk->trans field to NULL, the dangling pointer issue can be resolved, mitigating the risk associated with the Use-After-Free condition. Staying informed about known vulnerabilities and promptly applying security patches are essential steps to securing Linux systems.
Timeline
Published on: 11/19/2024 02:16:28 UTC
Last modified on: 12/19/2024 09:36:51 UTC