Vsock Kernel. The issue affects systems vsock: VM sockets using AF_VSOCK Learn a
The issue affects systems vsock: VM sockets using AF_VSOCK Learn about a recent Linux kernel vulnerability discovered in 2026 and solutions to mitigate it without rebooting. 8) both in the Qemu virtual machine and the host and QEMU 2. ko- Virtual Socket Protocol is a socket protocol similar to TCP/IP allowing communication between Virtual Machines and hypervisor or host NAME vsock - Linux VSOCK address family SYNOPSIS #include <sys/socket. h> #include <linux/vm_sockets. It is not a guarantee that the copy is elided. Build the kernel, make headers_install, and build these tests. To load the module run the following command: This article provides a summary of the important features and bug fixes implemented in the Linux vsock drivers (vsock. In early 2025, security researchers and kernel maintainers resolved a subtle but deadly use-after-free vulnerability in the Linux kernel’s vsock (virtual socket) implementation. This bug was formally Impact The vulnerability can lead to use-after-free conditions in the kernel's vsock subsystem, potentially resulting in system crashes, memory corruption, or privilege escalation. 8+ is 1. ko and vmw_vsock_vmci_transport. cloud-hypervisor only supports stream VSOCK sockets. DESCRIPTION top The VSOCK address family facilitates communication between virtual machines and the host they are running on. * * * In an effort to improve the out-of-the-box experience with Linux kernels for VMware users, VMware is working on readying the Virtual Machine Communication Interface (vmw_vmci) and Has anyone gotten Incus VM's to work on WSL-2. The virtio-vsock is based on the Firecracker Passing flag MSG_ZEROCOPY is a hint to the kernel to apply copy avoidance, and a contract that the kernel will queue a completion notification. h> stream_socket = socket(AF_VSOCK, SOCK_STREAM, 0); datagram_socket I am struggling with VMs in Incus. 2. Install the kernel and tests inside the guest. Then there are individual virtio drivers for specific device types that are registered to the We would like to show you a description here but the site won’t allow us. This address family is used by guest agents and hypervisor services that vsock provides a new backend for the guest VM‘s networking stack that talks to the vhost_vsock host kernel module. ko) contributed to the upstream vhost-vsock architecture Uses vhost driver framework to integrate with host network stack Both guest and host applications use sockets API Socket types: The target is to compile vhost_vsock as an kernel module, which should be marked as <M>. Boot the guest and ensure that the Summary VSOCK is a zero-configuration communication channel between host and guest Recent improvements in vsock make it more performant More optimizations to come After CVE-2024-50264, the Theori team reported five more issues in the Linux kernel vsock subsystem, and syzbot recently discovered two additional issues. I'm able to launch Incus containers without issue but when I run: incus launch CVE-2025-21756: vsock: Keep the binding until socket destruction Solution Verified - Updated June 4 2025 at 5:38 AM - English In the kernel, the virtio core contains the virtio bus driver and transport-specific drivers like virtio-pci and virtio-mmio. 4. The compile option is at Device Drivers -> [*] VHOST drivers -> <M> vhost virtio-vsock driver. Kernel 4. I am running vsock介绍 vsock 使用 内核配置 虚拟机kernel 将下面三个选项编译进kernel，而不是编译成模块，原因下面会介绍 A significant vulnerability in the Linux kernel's Virtual Socket (vsock) implementation, designated as CVE-2025-21756, has been identified that could allow local attackers to escalate 这样，在vsock_create初始化transport结构的时候，才能保证相应的结构体不为空。 VMCI设备 VMCI （Virtual Machine Communication Interface）是一种VMware I suspect you get the kernel entry you showed from the vsock module getting loaded (built-in in your case), but what LXD needs is vhost_vsock. 10 (release Date: 2013-06-30) This kernel module can be loaded in the host kernel to provide AF_VSOCK sockets for communicating with guests. This address family is used by guest agents and hypervisor services that need a The vhost kernel module then takes care of listening on the ioeventfd, processing the requests from the guest VM, and triggering an interrupt in the guest on completion of the request through the irqfd. 8, and the vhost_vsock module must be loaded or built-in (CONFIG_VHOST_VSOCK=y). The guests must have the Creating ubuntu Error: Failed instance creation: Failed creating instance record: Instance type “virtual-machine” is not supported on this server: vhost_vsock kernel module not loaded Seems The Linux kernel received a targeted fix for a subtle but potentially dangerous race in the AF_VSOCK transport: during a blocking connect(), if a signal or timeout arrived after the socket had CONFIG_VSOCKETS -vsock. 8+ is required on both The host Linux kernel version must be greater than or equal to v4. The host kernel module in turn uses the host kernel’s networking stack to transfer The VSOCK address family facilitates communication between virtual machines and the host they are running on. This address family is used by guest agents and hypervisor services CVE-2025-21756: Attack of the Vsock What started off as casual scrolling through the KernelCTF submissions quickly spiraled into a weeks-long deep dive into a In order to get vsock up and running we need a fairly recent kernel (> 4. After CVE-2024-50264, the Theori team reported five more issues in the Linux kernel vsock subsystem, and syzbot recently discovered two additional issues. VSOCK support VSOCK provides a way for guest and host to communicate through a socket. The error message below indicates that I need kernel module vhost_vsock. To take advantage of VM sockets (using virtio-vsock), the Linux kernel (on both the hypervisor and guest) and QEMU must be fairly up-to-date. In linux kernel since version 3. I believe these provide valuable insights into The narrow window between the socket being queued for disconnect and its resources being fully freed can cause the kernel to operate on a freed socket object, leading to a kernel crash or controlled code DESCRIPTION The VSOCK address family facilitates communication between virtual machines and the host they are running on. I believe these provide valuable insights into . 3. Install the kernel and tests on the host. I’m not sure how to add that kernel module.
