OpenSSL API관련 질문...

인터넷을 통해서 openssl 공부를 하다가

openssl api를 사용한 서버-클라이언트 소스코드를 구했습니다.

잘 돌아가긴 하더군요..

그런데 서버와 클라이언트 간에 패킷을 이더리얼로 잡아보니

only TCP만 잡힙니다 OTL

ssl handshake 과정도 안보이는것 같고..

그냥 TCP 이용해서 데이터만 보내는 것 같네요..

소스 올려 두겠습니다.

이 소스에선 원래 ssl(tls) handshake 안하는게 맞는건가요?

handshake를 하려면 openssl의 어떤 api를 사용해야 하는지 좀 알려주세요..

api가 너무 없네요..ㅠ_ㅠ

** 먼저 서버

#include
#include
#include
#include
#include
#include
#include
#include
#include
#include

#include /* SSLeay stuff */
#include
#include
#include
#include
#include

/* define HOME to be dir for key and cert files... */
#define HOME "./"

/* Make these what you want for cert & key files */
#define CERTF HOME "server-req.pem"
#define KEYF HOME "server-key.pem"

#define CHK_NULL(x) if ((x)==NULL) exit (1)
#define CHK_ERR(err,s) if ((err)==-1) { perror(s); exit(1); }
#define CHK_SSL(err) if ((err)==-1) { ERR_print_errors_fp(stderr); exit(2); }

void main ()
{
int err;
int listen_sd;
int sd;
struct sockaddr_in sa_serv;
struct sockaddr_in sa_cli;
size_t client_len;

SSL_CTX* ctx;
SSL* ssl;
X509* client_cert;

char* str;
char buf [4096];

SSL_METHOD *meth;

/* SSL preliminaries. We keep the certificate and key with the context. */
SSL_load_error_strings();
SSLeay_add_ssl_algorithms();
meth = TLSv1_server_method();

// create a new SSL_CTX object as framework for TLS/SSL enabled functions
ctx = SSL_CTX_new (meth);
if (!ctx) {
ERR_print_errors_fp(stderr);
exit(2);
}

if (SSL_CTX_use_certificate_file(ctx, CERTF, SSL_FILETYPE_PEM) <= 0) {
ERR_print_errors_fp(stderr);
exit(3);
}
if (SSL_CTX_use_PrivateKey_file(ctx, KEYF, SSL_FILETYPE_PEM) <= 0) {
ERR_print_errors_fp(stderr);
exit(4);
}
if (!SSL_CTX_check_private_key(ctx)) {
fprintf(stderr,"Private key does not match the certificate public key\n");
exit(5);
}

/* Prepare TCP socket for receiving connections */

// Create Internet Socket and Fill sockaddr_in
listen_sd = socket (AF_INET, SOCK_STREAM, 0);
CHK_ERR(listen_sd, "socket");

memset (&sa_serv, '\0', sizeof(sa_serv));
sa_serv.sin_family = AF_INET;
sa_serv.sin_addr.s_addr = INADDR_ANY;
sa_serv.sin_port = htons (1111); /* Server Port number */

// Bind
err = bind(listen_sd, (struct sockaddr*) &sa_serv, sizeof (sa_serv));
CHK_ERR(err, "bind");

// Listening
err = listen (listen_sd, 5);
CHK_ERR(err, "listen");

// Accept
client_len = sizeof(sa_cli);
sd = accept (listen_sd, (struct sockaddr*) &sa_cli, &client_len);
CHK_ERR(sd, "accept");

// Close Listening socket
close (listen_sd);

// Connected-client info.
printf ("Connection from %lx, port %d\n",
sa_cli.sin_addr.s_addr, sa_cli.sin_port);

// TCP connection is ready. Do server side SSL.
// create a new SSL structure for a connection
ssl = SSL_new (ctx);
CHK_NULL(ssl);

// connect the SSL object with a file descriptor
SSL_set_fd (ssl, sd);
err = SSL_accept (ssl);
CHK_SSL(err);

// Get the cipher - opt
printf ("SSL connection using %s\n", SSL_get_cipher (ssl));

// Get client's certificate (note: beware of dynamic allocation) - opt
client_cert = SSL_get_peer_certificate (ssl);
if (client_cert != NULL)
{
printf ("Client certificate:\n");

str = X509_NAME_oneline (X509_get_subject_name (client_cert), 0, 0);
CHK_NULL(str);
printf ("\t subject: %s\n", str);
free (str);

str = X509_NAME_oneline (X509_get_issuer_name (client_cert), 0, 0);
CHK_NULL(str);
printf ("\t issuer: %s\n", str);
free (str);

/* We could do all sorts of certificate verification stuff here before
deallocating the certificate. */

X509_free (client_cert);
}
else
{
printf ("Client does not have certificate.\n");
}

// DATA EXCHANGE - Receive message and send reply.
err = SSL_read (ssl, buf, sizeof(buf) - 1);
CHK_SSL(err);

buf[err] = '\0';
printf ("Got %d chars:'%s'\n", err, buf);

err = SSL_write (ssl, "I hear you.", strlen("I hear you."));
CHK_SSL(err);

/* Clean up. */
close (sd);
SSL_free (ssl);
SSL_CTX_free (ctx);
}

** 클라이언트

#include
#include
#include
#include
#include
#include
#include
#include

#include

#include
#include
#include
#include
#include

#define CHK_NULL(x) if ((x)==NULL) exit (1)
#define CHK_ERR(err,s) if ((err)==-1) { perror(s); exit(1); }
#define CHK_SSL(err) if ((err)==-1) { ERR_print_errors_fp(stderr); exit(2); }

void print_x509(SSL *ssl)
{
char *ascii_cert;
X509 *cert = SSL_get_peer_certificate(ssl);
BIO *b;
BUF_MEM *bptr;

b = BIO_new(BIO_s_mem());

if(X509_print(b, cert) > 0)
{
BIO_get_mem_ptr(b, &bptr);
ascii_cert = (char *)malloc(1 + bptr->length);
memcpy(ascii_cert, bptr->data, bptr->length);
}
else
{
ascii_cert = (char *)malloc(1024);
sprintf(ascii_cert, "This certificate has never been seen before and can't be shown\n");
}
BIO_free(b);

/* X.509 인증서 출력 */
printf("X.509:\n%s\n", ascii_cert);
}

void main (int argc, char **argv)
{
int err;
int sd;
struct sockaddr_in sa;

SSL_CTX* ctx;
SSL* ssl;
X509* server_cert;

char* str;
char buf [4096];
char hello[80];

SSL_METHOD *meth;

printf ("Message to send: ");
fgets (hello, 80, stdin);

SSLeay_add_ssl_algorithms();
//meth = SSLv2_client_method();
meth = TLSv1_client_method();
SSL_load_error_strings();
ctx = SSL_CTX_new (meth);
CHK_NULL(ctx);
CHK_SSL(err);

///////////////////////////////////////////////////////////////////////////////////////
// Create a socket and connect to server using normal socket calls.
sd = socket (AF_INET, SOCK_STREAM, 0);
CHK_ERR(sd, "socket");

memset (&sa, '\0', sizeof(sa));
sa.sin_family = AF_INET;
sa.sin_addr.s_addr = inet_addr ("203.247.40.139"); /* Server IP */
sa.sin_port = htons (atoi(argv[1])); /* Server Port number */

// Normal-connect
err = connect(sd, (struct sockaddr*) &sa, sizeof(sa));
CHK_ERR(err, "connect");

// Now we have TCP conncetion. Start SSL negotiation.
// create a new SSL structure for a connection
ssl = SSL_new (ctx);
CHK_NULL(ssl);

// connect the SSL object with a file descriptor
SSL_set_fd (ssl, sd);

// initiate the TLS/SSL handshake with an TLS/SSL server
err = SSL_connect (ssl);
CHK_SSL(err);

/*
* Following two steps are optional and not required for
* data exchange to be successful.
*/

printf ("SSL connection using %s\n", SSL_get_cipher (ssl));

// Get server's certificate (note: beware of dynamic allocation) - opt
server_cert = SSL_get_peer_certificate (ssl);
CHK_NULL(server_cert);
print_x509(ssl);

/*
printf ("Server certificate:\n");
str = X509_NAME_oneline (X509_get_subject_name (server_cert),0,0);
CHK_NULL(str);
printf ("\t subject: %s\n", str);
free (str);

str = X509_NAME_oneline (X509_get_issuer_name (server_cert),0,0);
CHK_NULL(str);
printf ("\t issuer: %s\n", str);
free (str);
*/

/*
* We could do all sorts of certificate verification stuff here before
* deallocating the certificate.
*/
X509_free (server_cert);

///////////////////////////////////////////////////////////////////////////////////////
// DATA EXCHANGE - Send a message and receive a reply.

//err = SSL_write (ssl, "Hello World!", strlen("Hello World!"));
//CHK_SSL(err);
err = SSL_write (ssl, hello, strlen(hello));
CHK_SSL(err);

err = SSL_read (ssl, buf, sizeof(buf) - 1);
CHK_SSL(err);
buf[err] = '\0';
printf ("Got %d chars:'%s'\n", err, buf);

// send SSL/TLS close_notify
SSL_shutdown (ssl);

/* Clean up. */

close (sd);
SSL_free (ssl);
SSL_CTX_free (ctx);
}