CVE-2026-23440: Linux内核IPSec ESN更新竞态条件漏洞

/* * Conceptual Proof of Concept (PoC) for CVE-2026-23440 * This PoC demonstrates the race condition logic. * Note: Exploiting this requires a specific environment (Linux kernel with vulnerable mlx5e driver, * Mellanox NIC, and IPSec offload configured). Triggering the race condition remotely involves * sending a high volume of traffic to trigger the ESN wrap and precise timing. * * The following Python code simulates the vulnerable logic flow. */ import threading import time class VulnerableDriver: def __init__(self): self.esn_event_arm = 0x0 # Event signaled self.esn_msb = 0 self.lock = threading.Lock() self.xfrm_state_locked = False def handle_esn_event_vulnerable(self): print("[Driver] ESN Event Detected") # 1. Validate Event if self.esn_event_arm == 0x0: print("[Driver] Event validated.") # 2. Vulnerability: Not re-arming (setting esn_event_arm to 0x1) here. # We proceed to modify xfrm state which releases the lock. print("[Driver] Updating xfrm state (releasing lock)...") self.modify_xfrm_state() # 3. Re-arm happens AFTER the lock is re-acquired. # Race window exists between step 2 and 3. self.esn_event_arm = 0x1 print("[Driver] Event re-armed.") def handle_esn_event_fixed(self): print("[Driver-Fixed] ESN Event Detected") # 1. Validate Event if self.esn_event_arm == 0x0: print("[Driver-Fixed] Event validated.") # 2. Fix: Re-arm IMMEDIATELY after validation. self.esn_event_arm = 0x1 print("[Driver-Fixed] Event re-armed immediately.") # 3. Now update xfrm state print("[Driver-Fixed] Updating xfrm state (releasing lock)...") self.modify_xfrm_state() def modify_xfrm_state(self): # Simulate releasing and re-acquiring lock with self.lock: self.xfrm_state_locked = True time.sleep(0.1) # Simulate work self.xfrm_state_locked = False # Simulate hardware sending a spurious event while we are processing # or the logic loop checking again quickly. print("[Hardware] Spurious event check...") if self.esn_event_arm == 0x0: print("[Hardware] Processing event again! (BUG)") self.esn_msb += 1 # Incorrect increment print(f"[Hardware] ESN MSB incremented to {self.esn_msb}") else: print("[Hardware] Event ignored (Armed).") # Simulation of the issue if __name__ == "__main__": print("--- Simulating Vulnerable Scenario ---") driver = VulnerableDriver() driver.handle_esn_event_vulnerable() # In a real race, an interrupt might trigger the check path again during modify_xfrm_state print("\n--- Simulating Fixed Scenario ---") driver_fixed = VulnerableDriver() driver_fixed.handle_esn_event_fixed()