对等体断开连接后未释放SSL内存

Question

我正在使用非阻塞套接字开发一个简单的多线程HTTP / s服务器，以基于Linux Epoll处理HTTP请求。它创建4/8个线程（结构SSLWorker），每个线程都可以接受和处理连接，除了SSL_CTX（结构SSLContext）之外，连接之间没有共享数据。

随着每个新的连接，内存将增长，并且在断开连接后，内存将永远不会释放。我不知道原因。似乎它与SSL代码有关，因为使用HTTP请求时不会发生。

使用valgrind，heaptrack和泄漏清理程序无济于事，因为似乎内存仍然可以访问并且未检测到泄漏。如何清理Connection struct SSL和BIO数据的正确方法和顺序？（freeSsl（））。关于我所缺少的任何帮助吗？

注意：-尝试使用Debian和自建的Openssl 1.1和1.1.1，它们的行为相同。-当客户端使用TLS 1.2时，内存增长更为明显-尝试禁用内部SSL SESSION缓存并设置SSL_MODE_RELEASE_BUFFERS。-从客户端开始断开连接。

struct SSLContext   //Shared between worker threads
    SSL_CTX *ssl_ctxnullptr;
    SSLContext()
        ERR_load_crypto_strings();
        ERR_load_SSL_strings();
        SSL_load_error_strings();
        OpenSSL_add_all_algorithms();
        int r = SSL_library_init();
        ssl_ctx = SSL_CTX_new(SSLv23_method());
        int r = SSL_CTX_use_certificate_file(ssl_ctx, global::cert_file.c_str(),
            SSL_FILETYPE_PEM); 
        r = SSL_CTX_use_PrivateKey_file(ssl_ctx, global::key_file.c_str(), SSL_FILETYPE_PEM); 
        r = SSL_CTX_check_private_key(ssl_ctx); 
    

    virtual ~SSLContext()
        SSL_CTX_free(ssl_ctx);
        ERR_free_strings();
    
;

struct Connection //Data associated to every connection

    int sock_fd;
    SSL *sslnullptr; 
    BIO *sbionullptr;// socket bio  
    BIO *ionullptr;// buffer bio  
    BIO *ssl_bionullptr;// ssl bio
    ~Connection() //free ssl objects
        if (ssl != nullptr) 
            SSL_set_shutdown(ssl, SSL_RECEIVED_SHUTDOWN);
            freeSsl();
            if(sock_fd > 0) ::close(sock_fd);
        
    
    void freeSsl() //free connection       
        //SSL_shutdown(ssl); it seems to be done by bellow free call.
        //SSL_free(ssl); it seems to be done by bellow free call.
        if(sbio != nullptr) 
            BIO_free(sbio);
            sbio = nullptr;
        
        if(io != nullptr) 
            BIO_flush(io);
            BIO_free(io);
            io = nullptr;
        
        if(ssl_bio != nullptr) 
            BIO_flush(ssl_bio);
            BIO_free(ssl_bio);     
            ssl_bio = nullptr; 
        
        ssl = nullptr;
    
    bool enableReadEvent(); //enable socket read events, set EPOLLIN | EPOLLET
    bool enableWriteEvent();//enable socket write event, set EPOLLOUT | EPOLLET 
;

struct SSLConnectionManager //ssl operations hanldler.

    static SSLContext ssl_context; 

    bool handleHandshake(Connection &ssl_connection) //Initialize connection and do hanshake
    
        if(ssl_connection.ssl != nullptr) ssl_connection.freeSsl();     
        ssl_connection.ssl = SSL_new(ssl_context->ssl_ctx);
        ssl_connection.sbio = BIO_new_socket(ssl_connection.sock_fd, BIO_CLOSE);
        SSL_set_bio(ssl_connection.ssl, ssl_connection.sbio, ssl_connection.sbio);
        ssl_connection.io = BIO_new(BIO_f_buffer());
        ssl_connection.ssl_bio = BIO_new(BIO_f_ssl());
        BIO_set_ssl(ssl_connection.ssl_bio, ssl_connection.ssl, BIO_CLOSE);
        BIO_push(ssl_connection.io, ssl_connection.ssl_bio);
        SSL_set_accept_state(ssl_connection.ssl);

        int r = SSL_do_handshake(ssl_connection.ssl); 
        if (r == 1) 
            ssl_connection.ssl_connected = true;   
            ssl_connection.enableReadEvent();
            return true;
        

        int err = SSL_get_error(ssl_connection.ssl, r);
        if (err == SSL_ERROR_WANT_WRITE || err == SSL_ERROR_WANT_READ)   
            ssl_connection.enableReadEvent();
            return true;
         
        //"SSL_do_handshake error, abort connection
        return false;    

    

    IO::IO_RESULT SSLConnectionManager::handleRead(Connection &ssl_connection) 
        if (!ssl_connection.ssl_connected) 
            return IO::IO_RESULT::SSL_NEED_HANDSHAKE;
        
        int rc = -1;
        int bytes_read = 0;
        for (;;) 
            rc = BIO_read(ssl_connection.io,
                ssl_connection.buffer + ssl_connection.buffer_size,
                static_cast<int>(MAX_DATA_SIZE - ssl_connection.buffer_size));        
            if (rc == 0) 
                return bytes_read > 0 ? IO::IO_RESULT::SUCCESS : IO::IO_RESULT::ZERO_DATA_READ;            
            else if (rc < 0) 
                if (BIO_should_retry(ssl_connection.io)) 
                    return IO::IO_RESULT::DONE_TRY_AGAIN;
                
                return IO::IO_RESULT::ERROR;
            
            bytes_read += rc;
            ssl_connection.buffer_size += static_cast<size_t>(rc);
        
        return IO::IO_RESULT::SUCCESS;
    

    IO::IO_RESULT SSLConnectionManager::handleWrite(Connection &ssl_connection,
        const char *data, size_t data_size, size_t &written) 
        if (!ssl_connection.ssl_connected) 
            return IO::IO_RESULT::SSL_NEED_HANDSHAKE; // after we call handleHanshake
        

        IO::IO_RESULT result;
        int rc = -1;
        written = 0;
        for (;;) 
            rc = BIO_write(ssl_connection.io, data + written, static_cast<int>(data_size - written));        
            if (rc == 0) 
                result = IO::IO_RESULT::DONE_TRY_AGAIN;
                break;
             else if (rc < 0) 
                if (BIO_should_retry(ssl_connection.io)) 
                    result = IO::IO_RESULT::DONE_TRY_AGAIN;             
                    break;
                 else 
                    return IO::IO_RESULT::ERROR;                    
                
             else 
                written += rc;
                if ((data_size - written) == 0) 
                    result = IO::IO_RESULT::SUCCESS;
                    break;
                ;
            
        
        BIO_flush(ssl_connection.io);  
        return result;
       
;

struct SSLWorker : EpollManager //Thread worker task.

    SSLConnectionManager ssl_connection_manager;

    bool onConnectEvent(Connection &ssl_connection)
        auto sock_fd  = accept(...);    
        Connection * new_connection = new  Connection(sock_fd);
        addToEventManager(*new_connection, EV_READ);
     

    void doWork() 
        is_running = true;
        int res = 0;
        epoll_event events[1024];
        while (is_running) 
            res = ::epoll_wait(epoll_fd, events, 1024, -1);
            if (res < 0)
                return;
            for (int i = 0; i < res; i++) 
                auto conn = static_cast<Connection *>(events[i].data.ptr);
                if (events[i].events & (EPOLLHUP | EPOLLERR | EPOLLRDHUP)) 
                    delete conn; //remote closed connection, free all
                 else 
                    if (events[i].events & EPOLLIN) 
                        if (conn->fd == global::listen_fd)             
                            onConnectEvent();
                            continue;
                         else             
                            ssl_connection_manager.handleRead(*conn);
                            processRequest();
                            conn.enableWriteEvent();
                        
                    
                    if (events[i].events & EPOLLOUT)    
                        ssl_connection_manager.handleWrite(*conn);
                    
                
            
        
    


;

在简短执行后，您会在这里看到什么堆跟踪报告泄漏。

leak stack