最近一直在学习SSL相关知识，也明白了理论相关知识，主要SSL基本概念和连接建立。主要依据PolarSSL开源库学习。学习完了之后就希望能给有所运用，就想用Qt写一个简单的程序，添加对SSL相关概念的把握和对PolarSSL库的运用。当然，终于希望是能够使用Qt做一个比較完好的工具，帮助大家更好的理解和学习SSL相关知识。这都是后话，在第一篇里面，我们就简单用样例展示怎样在Qt里面调用PolarSSL库。
这篇博客主要是解说Qt里面调用PolarSSL库，至于SSL相关概念在后面的博客再具体介绍。
SSL握手须要客户端和服务器端交互。这里我们分别介绍。
1、编译PolarSSL库
我们准备使用的方式就是编译PolarSSL为.a静态库，然后在Qt中连接，使用的PolarSSL的版本号是0.10.1。
下载相应的软件版本号。解压缩后在library文件夹下执行make就可以生成libpolarssl.a库文件，例如以下图：
2、服务器端
使用Qt设计一个简单的界面。在button的槽函数中进行相关的操作。也就是调用PolarSSL库函数进行编程。初始化ssl相关结构体，监听port。等等。
SSL中最重要的就是执行握手操作。这里须要注意一点，因为涉及到socket编程。像accept函数都是堵塞的。假设在gui主线程中调用会造成界面冻结，也就是我们常说的ANR。解决方法就是将这些操作放在一个线程中，Qt中创建一个线程比較easy。创建一个类，继承自QThread，实现run函数。就可以。最后启动线程也比較简单，调用该类的start()
函数就可以。
好了，不多说了。上代码。首先看看服务器端的代码结构：workThread即是线程。实现SSL相关的功能，监听套接字，实现SSL握手，读取客户端发来的消息，向客户端发送消息。
mianwindow即是主窗体界面，有个button，在button的槽函数中启动线程
代码：
project文件：
#-------------------------------------------------
#
# Project created by QtCreator 2014-05-11T22:28:07
#
#-------------------------------------------------
QT += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = MyPolarSSLToolSrv
TEMPLATE = app
INCLUDEPATH += /home/chenlong12580/develop/polarTool/polarssl/include
LIBS += -L "/home/chenlong12580/develop/polarTool/polarssl/lib/" -lpolarssl
SOURCES += main.cpp
widget.cpp
workthread.cpp
HEADERS += widget.h
workthread.h
FORMS += widget.ui线程类：
void WorkThread::run()
{
qDebug() << "I am a thread!";
int listen_fd = 0;
int client_fd =0;
int ret= 0;
havege_state hs;
ssl_context ssl;
ssl_session ssn;
x509_cert srvcert;
rsa_context rsa;
unsigned char buf[1024];
int len = 0;
memset( &srvcert, 0, sizeof( x509_cert ) );
ret = x509parse_crt( &srvcert, (unsigned char *) test_srv_crt,
strlen( test_srv_crt ) );
if( ret != 0 )
{
printf( " failed
! x509parse_crt returned %d
", ret );
return;
}
ret = x509parse_crt( &srvcert, (unsigned char *) test_ca_crt,
strlen( test_ca_crt ) );
if( ret != 0 )
{
printf( " failed
! x509parse_crt returned %d
", ret );
return;
}
ret = x509parse_key( &rsa, (unsigned char *) test_srv_key,
strlen( test_srv_key ), NULL, 0 );
if( ret != 0 )
{
printf( " failed
! x509parse_key returned %d
", ret );
return;
}
ret = net_bind( &listen_fd, NULL, 8443 );
if (0 != ret)
{
qDebug() << ret;
return;
}
qDebug() << "bind ok";
/* socket is block */
ret = net_accept( listen_fd, &client_fd, NULL );
if (0 != ret)
{
return;
}
qDebug() << "accept ok";
havege_init( &hs );
ret = ssl_init( &ssl );
if (0 != ret)
{
return;
}
ssl_set_endpoint( &ssl, SSL_IS_SERVER );
ssl_set_authmode( &ssl, SSL_VERIFY_NONE );
ssl_set_rng( &ssl, havege_rand, &hs );
ssl_set_dbg( &ssl, my_debug, stdout );
ssl_set_bio( &ssl, net_recv, &client_fd,
net_send, &client_fd );
ssl_set_scb( &ssl, my_get_session,
my_set_session );
ssl_set_ciphers( &ssl, my_ciphers );
ssl_set_session( &ssl, 1, 0, &ssn );
memset( &ssn, 0, sizeof( ssl_session ) );
ssl_set_ca_chain( &ssl, srvcert.next, NULL );
ssl_set_own_cert( &ssl, &srvcert, &rsa );
ssl_set_dh_param( &ssl, my_dhm_P, my_dhm_G );
qDebug() << "before ssl_handshake ok";
while( ( ret = ssl_handshake( &ssl ) ) != 0 )
{
;
}
qDebug() << "ssl_handshake ok";
do
{
len = sizeof( buf ) - 1;
memset( buf, 0, sizeof( buf ) );
ret = ssl_read( &ssl, buf, len );
if( ret == POLARSSL_ERR_NET_TRY_AGAIN )
continue;
if( ret <= 0 )
{
switch( ret )
{
case POLARSSL_ERR_SSL_PEER_CLOSE_NOTIFY:
printf( " connection was closed gracefully
" );
break;
case POLARSSL_ERR_NET_CONN_RESET:
printf( " connection was reset by peer
" );
break;
default:
printf( " ssl_read returned %d
", ret );
break;
}
break;
}
len = ret;
printf( " %d bytes read
%s", len, (char *) buf );
}while( 0 );
char *cc = (char *)buf;
QString ss(cc);
qDebug() << ss;
(void)sprintf( (char *) buf, HTTP_RESPONSE,
ssl_get_cipher( &ssl ) );
while( ( ret = ssl_write( &ssl, buf, len ) ) <= 0 )
{
if( ret == POLARSSL_ERR_NET_CONN_RESET )
{
printf( " failed
! peer closed the connection
" );
return;
}
if( ret != POLARSSL_ERR_NET_TRY_AGAIN )
{
printf( " failed
! ssl_write returned %d
", ret );
return;
}
}
ssl_close_notify( &ssl );
net_close( client_fd );
x509_free( &srvcert );
rsa_free( &rsa );
ssl_free( &ssl );
cur = s_list_1st;
while( cur != NULL )
{
prv = cur;
cur = cur->next;
memset( prv, 0, sizeof( ssl_session ) );
free( prv );
}
memset( &ssl, 0, sizeof( ssl_context ) );
}
主窗体类：
#include "widget.h"
#include "ui_widget.h"
#include <QFileDialog>
#include <QDebug>
#include <QMessageBox>
#include "workthread.h"
#include "polarssl/havege.h"
#include "polarssl/certs.h"
#include "polarssl/x509.h"
#include "polarssl/ssl.h"
#include "polarssl/net.h"
Widget::Widget(QWidget *parent) :
QWidget(parent),
ui(new Ui::Widget)
{
ui->setupUi(this);
qDebug() << "server";
connect(this, SIGNAL(emit_parse_cer()), this, SLOT(slot_parse_cer()));
}
Widget::~Widget()
{
delete ui;
}
void Widget::on_BrowseBtn_clicked()
{
QString pathStr = QFileDialog::getOpenFileName(this, QString("选择证书文件"), QString("C:\Users\Administrator\Desktop"), QString("*.*"));
if (pathStr.length() == 0)
{
qDebug() << "please select a cer file!";
return;
}
ui->PathEdit->setText(pathStr);
emit emit_parse_cer();
}
void Widget::slot_parse_cer()
{
x509_cert crt;
memset(&crt, 0, sizeof(crt));
int res = x509parse_crtfile( &crt, ui->PathEdit->text().toLatin1().data());
if (0 != res)
{
QMessageBox::warning(this, "警告", "解析证书失败，请选择正确的证书文件", QMessageBox::Ok);
return;
}
ui->CrtInfo->setText(QString("是否为根证书：") + QString::number(crt.ca_istrue));
ui->CrtInfo->append(QString("证书版本号号：") + QString::number(crt.version));
ui->CrtInfo->append(QString("有效期：") + QString::number(crt.valid_from.year) + "-" + QString::number(crt.valid_from.mon)
+ QString(" 到：") + QString::number(crt.valid_to.year) + "-" + QString::number(crt.valid_to.mon));
qDebug() << crt.ca_istrue;
qDebug() << crt.valid_from.year;
}
void Widget::on_pushButton_clicked()
{
WorkThread *workThread = new WorkThread;
workThread->start();
}3、客户端
客户端比較简单，直接在界面类进行的SSL功能相关的实现，就是创建套接字，链接服务器，进行SSL握手，向服务器发消息，读取服务器发来的消息。
project文件：
#-------------------------------------------------
#
# Project created by QtCreator 2014-05-11T22:28:07
#
#-------------------------------------------------
QT += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = MyPolarSSLToolCli
TEMPLATE = app
INCLUDEPATH += /home/chenlong12580/develop/polarTool/polarssl/include
LIBS += -L "/home/chenlong12580/develop/polarTool/polarssl/lib/" -lpolarssl
SOURCES += main.cpp
widget.cpp
HEADERS += widget.h
FORMS += widget.ui
主窗体类：
#include "widget.h"
#include "ui_widget.h"
#include <QFileDialog>
#include <QDebug>
#include <QMessageBox>
#include "polarssl/havege.h"
#include "polarssl/certs.h"
#include "polarssl/x509.h"
#include "polarssl/ssl.h"
#include "polarssl/net.h"
#define SERVER_PORT 8443
/*
#define SERVER_NAME "localhost"
#define GET_REQUEST "GET / HTTP/1.0
"
*/
#define SERVER_NAME "polarssl.org"
#define GET_REQUEST
"GET /hello/ HTTP/1.1
"
"Host: polarssl.org
"
#define DEBUG_LEVEL 0
void my_debug( void *ctx, int level, char *str )
{
if( level < DEBUG_LEVEL )
{
fprintf( (FILE *) ctx, "%s", str );
fflush( (FILE *) ctx );
}
}
Widget::Widget(QWidget *parent) :
QWidget(parent),
ui(new Ui::Widget)
{
ui->setupUi(this);
qDebug() << "client";
connect(this, SIGNAL(emit_parse_cer()), this, SLOT(slot_parse_cer()));
}
Widget::~Widget()
{
delete ui;
}
void Widget::on_BrowseBtn_clicked()
{
QString pathStr = QFileDialog::getOpenFileName(this, QString("选择证书文件"), QString("C:\Users\Administrator\Desktop"), QString("*.*"));
if (pathStr.length() == 0)
{
qDebug() << "please select a cer file!";
return;
}
ui->PathEdit->setText(pathStr);
emit emit_parse_cer();
}
void Widget::slot_parse_cer()
{
x509_cert crt;
memset(&crt, 0, sizeof(crt));
int res = x509parse_crtfile( &crt, ui->PathEdit->text().toLatin1().data());
if (0 != res)
{
QMessageBox::warning(this, "警告", "解析证书失败，请选择正确的证书文件", QMessageBox::Ok);
return;
}
ui->CrtInfo->setText(QString("是否为根证书：") + QString::number(crt.ca_istrue));
ui->CrtInfo->append(QString("证书版本号号：") + QString::number(crt.version));
ui->CrtInfo->append(QString("有效期：") + QString::number(crt.valid_from.year) + "-" + QString::number(crt.valid_from.mon)
+ QString(" 到：") + QString::number(crt.valid_to.year) + "-" + QString::number(crt.valid_to.mon));
qDebug() << crt.ca_istrue;
qDebug() << crt.valid_from.year;
}
void Widget::on_pushButton_clicked()
{
int ret, len, server_fd;
unsigned char buf[1024];
havege_state hs;
ssl_context ssl;
ssl_session ssn;
/*
* 0. Initialize the RNG and the session data
*/
havege_init( &hs );
memset( &ssn, 0, sizeof( ssl_session ) );
/*
* 1. Start the connection
*/
printf( "
. Connecting to tcp/%s/%4d...", SERVER_NAME,
SERVER_PORT );
fflush( stdout );
if( ( ret = net_connect( &server_fd, "127.0.0.1",
SERVER_PORT ) ) != 0 )
{
printf( " failed
! net_connect returned %d
", ret );
return;
}
printf( " ok
" );
/*
* 2. Setup stuff
*/
printf( " . Setting up the SSL/TLS structure..." );
fflush( stdout );
if( ( ret = ssl_init( &ssl ) ) != 0 )
{
printf( " failed
! ssl_init returned %d
", ret );
return;
}
printf( " ok
" );
ssl_set_endpoint( &ssl, SSL_IS_CLIENT );
ssl_set_authmode( &ssl, SSL_VERIFY_NONE );
ssl_set_rng( &ssl, havege_rand, &hs );
ssl_set_dbg( &ssl, my_debug, stdout );
ssl_set_bio( &ssl, net_recv, &server_fd,
net_send, &server_fd );
ssl_set_ciphers( &ssl, ssl_default_ciphers );
ssl_set_session( &ssl, 1, 600, &ssn );
/*
* 3. Write the GET request
*/
printf( " > Write to server:" );
fflush( stdout );
len = sprintf( (char *) buf, GET_REQUEST );
while( ( ret = ssl_write( &ssl, buf, len ) ) <= 0 )
{
if( ret != POLARSSL_ERR_NET_TRY_AGAIN )
{
printf( " failed
! ssl_write returned %d
", ret );
return;
}
}
len = ret;
printf( " %d bytes written
%s", len, (char *) buf );
/*
* 7. Read the HTTP response
*/
printf( " < Read from server:" );
fflush( stdout );
do
{
len = sizeof( buf ) - 1;
memset( buf, 0, sizeof( buf ) );
ret = ssl_read( &ssl, buf, len );
if( ret == POLARSSL_ERR_NET_TRY_AGAIN )
continue;
if( ret == POLARSSL_ERR_SSL_PEER_CLOSE_NOTIFY )
break;
if( ret <= 0 )
{
printf( "failed
! ssl_read returned %d
", ret );
break;
}
len = ret;
printf( " %d bytes read
%s", len, (char *) buf );
}
while( 0 );
char *cc= (char *)buf;
QString ss(cc);
qDebug() << ss;
ssl_close_notify( &ssl );
return;
}
4、执行效果
以下说说执行的效果，首先启动服务器端。服务器端启动线程，监听套接字：
接着启动客户端。客户端链接服务器端，写入消息，读取服务器端的响应：
最后依据打印能够看出服务器端和客户端握手成功。写入读取消息成功：
我们能够依据抓包来看看SSL握手的过程。例如以下：
通过抓包能够看到服务器端和客户端的握手过程，以及在不同的握手阶段中做得事情：
服务器端：
/*
* SSL handshake -- server side
*/
int ssl_handshake_server( ssl_context *ssl )
{
int ret = 0;
SSL_DEBUG_MSG( 2, ( "=> handshake server" ) );
while( ssl->state != SSL_HANDSHAKE_OVER )
{
SSL_DEBUG_MSG( 2, ( "server state: %d", ssl->state ) );
if( ( ret = ssl_flush_output( ssl ) ) != 0 )
break;
switch( ssl->state )
{
case SSL_HELLO_REQUEST:
ssl->state = SSL_CLIENT_HELLO;
break;
/*
* <== ClientHello
*/
case SSL_CLIENT_HELLO:
ret = ssl_parse_client_hello( ssl );
break;
/*
* ==> ServerHello
* Certificate
* ( ServerKeyExchange )
* ( CertificateRequest )
* ServerHelloDone
*/
case SSL_SERVER_HELLO:
ret = ssl_write_server_hello( ssl );
break;
case SSL_SERVER_CERTIFICATE:
ret = ssl_write_certificate( ssl );
break;
case SSL_SERVER_KEY_EXCHANGE:
ret = ssl_write_server_key_exchange( ssl );
break;
case SSL_CERTIFICATE_REQUEST:
ret = ssl_write_certificate_request( ssl );
break;
case SSL_SERVER_HELLO_DONE:
ret = ssl_write_server_hello_done( ssl );
break;
/*
* <== ( Certificate/Alert )
* ClientKeyExchange
* ( CertificateVerify )
* ChangeCipherSpec
* Finished
*/
case SSL_CLIENT_CERTIFICATE:
ret = ssl_parse_certificate( ssl );
break;
case SSL_CLIENT_KEY_EXCHANGE:
ret = ssl_parse_client_key_exchange( ssl );
break;
case SSL_CERTIFICATE_VERIFY:
ret = ssl_parse_certificate_verify( ssl );
break;
case SSL_CLIENT_CHANGE_CIPHER_SPEC:
ret = ssl_parse_change_cipher_spec( ssl );
break;
case SSL_CLIENT_FINISHED:
ret = ssl_parse_finished( ssl );
break;
/*
* ==> ChangeCipherSpec
* Finished
*/
case SSL_SERVER_CHANGE_CIPHER_SPEC:
ret = ssl_write_change_cipher_spec( ssl );
break;
case SSL_SERVER_FINISHED:
ret = ssl_write_finished( ssl );
break;
case SSL_FLUSH_BUFFERS:
SSL_DEBUG_MSG( 2, ( "handshake: done" ) );
ssl->state = SSL_HANDSHAKE_OVER;
break;
default:
SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
}
if( ret != 0 )
break;
}
SSL_DEBUG_MSG( 2, ( "<= handshake server" ) );
return( ret );
}客户端：
/*
* SSL handshake -- client side
*/
int ssl_handshake_client( ssl_context *ssl )
{
int ret = 0;
SSL_DEBUG_MSG( 2, ( "=> handshake client" ) );
while( ssl->state != SSL_HANDSHAKE_OVER )
{
SSL_DEBUG_MSG( 2, ( "client state: %d", ssl->state ) );
if( ( ret = ssl_flush_output( ssl ) ) != 0 )
break;
switch( ssl->state )
{
case SSL_HELLO_REQUEST:
ssl->state = SSL_CLIENT_HELLO;
break;
/*
* ==> ClientHello
*/
case SSL_CLIENT_HELLO:
ret = ssl_write_client_hello( ssl );
break;
/*
* <== ServerHello
* Certificate
* ( ServerKeyExchange )
* ( CertificateRequest )
* ServerHelloDone
*/
case SSL_SERVER_HELLO:
ret = ssl_parse_server_hello( ssl );
break;
case SSL_SERVER_CERTIFICATE:
ret = ssl_parse_certificate( ssl );
break;
case SSL_SERVER_KEY_EXCHANGE:
ret = ssl_parse_server_key_exchange( ssl );
break;
case SSL_CERTIFICATE_REQUEST:
ret = ssl_parse_certificate_request( ssl );
break;
case SSL_SERVER_HELLO_DONE:
ret = ssl_parse_server_hello_done( ssl );
break;
/*
* ==> ( Certificate/Alert )
* ClientKeyExchange
* ( CertificateVerify )
* ChangeCipherSpec
* Finished
*/
case SSL_CLIENT_CERTIFICATE:
ret = ssl_write_certificate( ssl );
break;
case SSL_CLIENT_KEY_EXCHANGE:
ret = ssl_write_client_key_exchange( ssl );
break;
case SSL_CERTIFICATE_VERIFY:
ret = ssl_write_certificate_verify( ssl );
break;
case SSL_CLIENT_CHANGE_CIPHER_SPEC:
ret = ssl_write_change_cipher_spec( ssl );
break;
case SSL_CLIENT_FINISHED:
ret = ssl_write_finished( ssl );
break;
/*
* <== ChangeCipherSpec
* Finished
*/
case SSL_SERVER_CHANGE_CIPHER_SPEC:
ret = ssl_parse_change_cipher_spec( ssl );
break;
case SSL_SERVER_FINISHED:
ret = ssl_parse_finished( ssl );
break;
case SSL_FLUSH_BUFFERS:
SSL_DEBUG_MSG( 2, ( "handshake: done" ) );
ssl->state = SSL_HANDSHAKE_OVER;
break;
default:
SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
}
if( ret != 0 )
break;
}
SSL_DEBUG_MSG( 2, ( "<= handshake client" ) );
return( ret );
}版权声明：本文博客原创文章。博客，未经同意，不得转载。