问题描述
我有一个客户端/服务器通信,需要升级为SSL通信。目前,我有一个用于发送和接收tcp数据的网络套接字。
- 客户端将tcp connect()发送到服务器。
- 服务器已实现了接受部分,接受连接后,服务器进入选择循环,等待进一步的操作。
我尝试过的事情:
完成tcp connect()之后,得到的fd是用于openssl SSL_set_fd(ssl,fd)的东西。在接受网络之后,在服务器端,我将连接升级为非阻塞状态,并执行SSL_accept,成功调用了SSL_connect()客户端(我已经处理了所有证书和其他所需的工作)。
我需要了解的内容:
-
SSL_accept()返回带有SSL_ERROR_WANT_READ的-1,我收到的一些输入建议我将其置于“ while”循环中,等待ssl接受完成。通过最终在ssl_accept上循环多次来解决该问题。困惑是我应该在这里循环还是返回选择循环。回到选择循环,我看到网络选择立即弹出,这可能是由于ssl_connect提供的一些数据。这是正确的方法吗?
-
我已将X字节在客户端与它执行读取操作SSL_write(),其被成功发送,当选择弹出具有读,我做一个SSL_read(),但它小于X,因此,我再次通过SSL_read()进行迭代,仅看到连续读取返回0个字节。同样的问题在这里,我应该在SSL_read()上循环多长时间,我是否必须循环,或者必须选择并等待。
-
如果我传递的SSL_read(ssl,buf,bytes)个字节多于接收到的字节,会发生什么情况?
我在初次读取后尝试使用SSL_pending(),但它始终返回0。因为那里显然缺少数据。 客户代码
ssl = SSL_new(ctx);
SSL_set_fd(ssl,fd);
if (SSL_connect(ssl) < 0 )
{
/* Log failure */
return(-1);
} else {
ssl_write_return = SSL_write(ssl,msg,req_len);
switch(SSL_get_error(ssl,ssl_write_return))
{
case SSL_ERROR_NONE:
...
default:
...
SSL_free(ssl);
}
}
SSL_CTX_free(ctx);
服务器代码
ssl = SSL_new(ctx);
SSL_set_fd(ssl,session->fd);
while(TRUE){
if ((ssl_accept_ret =SSL_accept(ssl)) != 1){
log ("ssl_accept failed with %d\n",ssl_accept_ret);
switch(SSL_get_error(ssl,ssl_accept_ret )){
case SSL_ERROR_NONE:
ERR_error_string_n(ERR_get_error(),err_msg,sizeof(err_msg));
break;
case SSL_ERROR_SSL:
ERR_error_string_n(ERR_get_error(),sizeof(err_msg));
break;
case SSL_ERROR_WANT_READ:
ERR_error_string_n(ERR_get_error(),sizeof(err_msg));
continue;
case SSL_ERROR_WANT_WRITE:
ERR_error_string_n(ERR_get_error(),sizeof(err_msg));
continue;
case SSL_ERROR_SYSCALL:
ERR_error_string_n(ERR_get_error(),sizeof(err_msg));
break;
case SSL_ERROR_ZERO_RETURN:
ERR_error_string_n(ERR_get_error(),sizeof(err_msg));
break;
case SSL_ERROR_WANT_CONNECT:
}
return(-1);
} else {
log ("ssl_accept was successful with %d\n",ssl_accept_ret);
return 0;
}
}
服务器读取代码
while(TRUE){
ret = SSL_read(session->ssl,buf,sizeof(buf));
if (ret<=0){
switch(SSL_get_error(session->ssl,ret)){
case SSL_ERROR_NONE:
ERR_error_string_n(ERR_get_error(),sizeof(err_msg));
continue;
case SSL_ERROR_SYSCALL:
ERR_error_string_n(ERR_get_error(),sizeof(err_msg));
break;
case SSL_ERROR_SSL:
ERR_error_string_n(ERR_get_error(),sizeof(err_msg));
break;
default:
ERR_error_string_n(ERR_get_error(),sizeof(err_msg));
break;
}
exit_select_loop()
} else {
log( "ssl_read was successful with %d and %s \n",ret,buf);
do{
ret = SSL_read(session->ssl,sizeof(buf));
log("ssl_read %d and %s \n",buf);
}while(SSL_pending(session->ssl)!=0 && (SSL_get_error(session->ssl,ret) == SSL_ERROR_WANT_WRITE || SSL_ERROR_WANT_READ));
}
}
解决方法
我在网站上找到了有效的ssl代码,您可以尝试:
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <strings.h>
#include <errno.h>
#include <netinet/in.h>
#include <netdb.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/select.h>
#include <netinet/tcp.h>
#include <ctype.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
//#include "imapfilter.h"
//#include "session.h"
#define TCP_DEFAULTBACK_LOG 15
#define HTTP_RESPON_TIMEOUT 15
//#define FORMAT_HTTPCHECK_REQ(buf,serv,port) snprintf(buf,sizeof(buf)-1,"GET /api/v1/echo/ HTTP/1.1\r\nHost: %s:%d\r\n\r\n",port)
#define FORMAT_HTTPCHECK_REQ(buf,"CONNECT 192.168.1.1 HTTP/1.1\r\nHost: %s:%d\r\n\r\n",port)
#if OPENSSL_VERSION_NUMBER >= 0x1010000fL
SSL_CTX *sslctx = NULL;
#else
SSL_CTX *ssl23ctx = NULL;
#ifndef OPENSSL_NO_SSL3_METHOD
SSL_CTX *ssl3ctx = NULL;
#endif
#ifndef OPENSSL_NO_TLS1_METHOD
SSL_CTX *tls1ctx = NULL;
#endif
#ifndef OPENSSL_NO_TLS1_1_METHOD
SSL_CTX *tls11ctx = NULL;
#endif
#ifndef OPENSSL_NO_TLS1_2_METHOD
SSL_CTX *tls12ctx = NULL;
#endif
#endif
/* IMAP session. */
typedef struct session {
int socket; /* Socket. */
SSL *sslconn; /* SSL connection. */
} session;
#define error printf
static int
open_connection(session *ssn,const char* serv,uint16_t port,const char* sslproto);
static int
close_connection(session *ssn);
static ssize_t
socket_read(session *ssn,char *buf,size_t len,long timeout,int timeoutfail,int *interrupt);
static ssize_t
socket_write(session *ssn,const char *buf,size_t len);
static int
open_secure_connection(session *ssn,const char* sslproto);
static int
close_secure_connection(session *ssn);
static ssize_t
socket_secure_read(session *ssn,size_t len);
static ssize_t
socket_secure_write(session *ssn,size_t len);
/*
* Connect to mail server.
*/
static int
open_connection(session *ssn,const char* sslproto)
{
struct addrinfo hints,*res,*ressave;
int n,sockfd;
char portstr[32];
sprintf(portstr,"%d",portstr);
memset(&hints,sizeof(struct addrinfo));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
n = getaddrinfo(serv,portstr,&hints,&res);
if (n < 0) {
error("gettaddrinfo; %s\n",gai_strerror(n));
return -1;
}
ressave = res;
sockfd = -1;
while (res) {
sockfd = socket(res->ai_family,res->ai_socktype,res->ai_protocol);
if (sockfd >= 0) {
if (connect(sockfd,res->ai_addr,res->ai_addrlen) == 0)
break;
sockfd = -1;
}
res = res->ai_next;
}
if (ressave)
freeaddrinfo(ressave);
if (sockfd == -1) {
error("error while initiating connection to %s at port %d\n",port);
return -1;
}
ssn->socket = sockfd;
if (sslproto) {
if (open_secure_connection(ssn,sslproto) == -1) {
close_connection(ssn);
return -1;
}
}
return ssn->socket;
}
/*
* Initialize SSL/TLS connection.
*/
static int
open_secure_connection(session *ssn,const char* sslproto)
{
int r,e;
SSL_CTX *ctx = NULL;
#if OPENSSL_VERSION_NUMBER >= 0x1010000fL
if (sslctx)
ctx = sslctx;
#else
if (ssl23ctx)
ctx = ssl23ctx;
if (sslproto) {
#ifndef OPENSSL_NO_SSL3_METHOD
if (ssl3ctx && !strcasecmp(sslproto,"ssl3"))
ctx = ssl3ctx;
#endif
#ifndef OPENSSL_NO_TLS1_METHOD
if (tls1ctx && !strcasecmp(sslproto,"tls1"))
ctx = tls1ctx;
#endif
#ifndef OPENSSL_NO_TLS1_1_METHOD
if (tls11ctx && !strcasecmp(sslproto,"tls1.1"))
ctx = tls11ctx;
#endif
#ifndef OPENSSL_NO_TLS1_2_METHOD
if (tls12ctx && !strcasecmp(sslproto,"tls1.2"))
ctx = tls12ctx;
#endif
}
#endif
if (ctx == NULL) {
error("initiating SSL connection to %s; protocol version "
"not supported by current build",serv);
goto fail;
}
if (!(ssn->sslconn = SSL_new(ctx)))
goto fail;
#if OPENSSL_VERSION_NUMBER >= 0x1000000fL
r = SSL_set_tlsext_host_name(ssn->sslconn,serv);
if (r == 0) {
error("failed setting the Server Name Indication (SNI) to "
"%s; %s\n",ERR_error_string(ERR_get_error(),NULL));
goto fail;
}
#endif
SSL_set_fd(ssn->sslconn,ssn->socket);
for (;;) {
if ((r = SSL_connect(ssn->sslconn)) > 0)
break;
switch (SSL_get_error(ssn->sslconn,r)) {
case SSL_ERROR_ZERO_RETURN:
error("initiating SSL connection to %s; the "
"connection has been closed cleanly\n",serv);
goto fail;
case SSL_ERROR_NONE:
case SSL_ERROR_WANT_CONNECT:
case SSL_ERROR_WANT_ACCEPT:
case SSL_ERROR_WANT_X509_LOOKUP:
case SSL_ERROR_WANT_READ:
case SSL_ERROR_WANT_WRITE:
break;
case SSL_ERROR_SYSCALL:
e = ERR_get_error();
if (e == 0 && r == 0)
error("initiating SSL connection to %s; EOF in "
"violation of the protocol\n",serv);
else if (e == 0 && r == -1)
error("initiating SSL connection to %s; %s\n",strerror(errno));
else
error("initiating SSL connection to %s; %s\n",ERR_error_string(e,NULL));
goto fail;
case SSL_ERROR_SSL:
error("initiating SSL connection to %s; %s\n",NULL));
goto fail;
default:
break;
}
}
// TODO: ignore cert if (get_option_boolean("certificates") && get_cert(ssn) == -1)
// goto fail;
return 0;
fail:
ssn->sslconn = NULL;
return -1;
}