CVE-2026-43106 Linux Kernel cachefiles引用计数错误

/* * PoC for CVE-2026-43106: cachefiles dentry refcount issue * This code conceptually triggers the vulnerable path. * Note: Exploiting kernel vulnerabilities requires a specific environment. */ #include <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <unistd.h> #include <sys/stat.h> // Conceptual trigger for cachefiles_cull() void trigger_vulnerability() { // Setup: Ensure cachefiles is enabled and a cache is bound. // The vulnerability occurs when the kernel tries to cull an object. int fd = open("/tmp/cachefiles_test", O_RDWR | O_CREAT, 0644); if (fd < 0) { perror("Failed to open file"); return; } printf("Attempting to trigger cachefiles_cull logic...\n"); // In a real scenario, one would interact with the cachefiles daemon // or manipulate the filesystem to force a cull operation on a dentry // that is in the specific state required to hit the bug. // Simulate interaction that leads to cull write(fd, "test data", 9); close(fd); // The kernel internal function cachefiles_cull() would be called // leading to the refcount drop in cachefiles_bury_object(). } int main() { printf("CVE-2026-43106 PoC Trigger\n"); trigger_vulnerability(); return 0; }