CVE-2025-40039 Linux ksmbd RPC句柄竞态条件漏洞

// CVE-2025-40039 PoC - Race Condition in ksmbd RPC Handle List // This PoC demonstrates the race condition by spawning multiple threads // that concurrently call RPC operations to trigger the race condition #include <stdio.h> #include <pthread.h> #include <unistd.h> #include <stdlib.h> // Simulated ksmbd structures typedef struct { void *rpc_handle_list; // XArray structure void *rpc_lock; // rw_semaphore } ksmbd_session_t; ksmbd_session_t global_session; volatile int shared_counter = 0; volatile int race_triggered = 0; // Simulated vulnerable function: ksmbd_session_rpc_open void* ksmbd_session_rpc_open(void* arg) { int thread_id = *(int*)arg; // VULNERABLE: Using read lock for write operation (xa_store/xa_erase) // Should use write lock (down_write) for modifying XArray // down_read(&session->rpc_lock); // Incorrect lock type for (int i = 0; i < 1000; i++) { // Simulate xa_store() operation shared_counter++; // Simulate xa_erase() operation shared_counter--; // Check for race condition indicators if (shared_counter != 0) { race_triggered = 1; printf("[Thread %d] Race condition detected! counter=%d\n", thread_id, shared_counter); } } // up_read(&session->rpc_lock); return NULL; } // Simulated vulnerable function: ksmbd_session_rpc_method void* ksmbd_session_rpc_method(void* arg) { int thread_id = *(int*)arg; // VULNERABLE: No lock at all when accessing XArray with xa_load() // Should use read lock (down_read) for read-only access for (int i = 0; i < 1000; i++) { // Simulate xa_load() without lock int temp = shared_counter; // Simulate use-after-free scenario if (temp < 0) { printf("[Thread %d] Potential use-after-free detected!\n", thread_id); } } return NULL; } int main() { pthread_t threads[8]; int thread_ids[8]; printf("CVE-2025-40039 PoC - ksmbd RPC Handle Race Condition\n"); printf("=====================================================\n\n"); // Create threads to trigger race condition for (int i = 0; i < 4; i++) { thread_ids[i] = i; pthread_create(&threads[i], NULL, ksmbd_session_rpc_open, &thread_ids[i]); } for (int i = 4; i < 8; i++) { thread_ids[i] = i; pthread_create(&threads[i], NULL, ksmbd_session_rpc_method, &thread_ids[i]); } // Wait for all threads for (int i = 0; i < 8; i++) { pthread_join(threads[i], NULL); } printf("\nFinal counter value: %d\n", shared_counter); printf("Race condition triggered: %s\n", race_triggered ? "YES" : "NO"); if (race_triggered) { printf("\n[!] Vulnerability confirmed: Race condition in ksmbd RPC handle access\n"); return 1; } return 0; } // Compilation: gcc -pthread -o cve_poc cve_poc.c // Note: This is a simplified PoC for demonstration purposes. // Real exploitation requires triggering ksmbd's SMB/RPC processing paths.