I'm trying use an SSL client/server example from: http://simplestcodings.blogspot.com.br/2010/08/secure-server-client-using-openssl-in-c.html to create a secure connection using SSLv3. I made some changes for request the certificate on server-side, the communication works fine and is understood in both sides. But my problem is that when the client connects to server, the SSLv3 protocol communication is not working. I used Wireshark to inspect the protocol field which show as TCP, or IPA (RSL Malformed Packet). Can someone please help me? Thanks!
I've created my certificates following the tutorial https://help.ubuntu.com/community/OpenSSL.
Here is my client code:
// SSL-Client.c
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <malloc.h>
#include <string.h>
#include <sys/socket.h>
#include <resolv.h>
#include <netdb.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
#define FAIL -1
//Added the LoadCertificates how in the server-side makes.
void LoadCertificates(SSL_CTX* ctx, char* CertFile, char* KeyFile)
{
/* set the local certificate from CertFile */
if ( SSL_CTX_use_certificate_file(ctx, CertFile, SSL_FILETYPE_PEM) <= 0 )
{
ERR_print_errors_fp(stderr);
abort();
}
/* set the private key from KeyFile (may be the same as CertFile) */
if ( SSL_CTX_use_PrivateKey_file(ctx, KeyFile, SSL_FILETYPE_PEM) <= 0 )
{
ERR_print_errors_fp(stderr);
abort();
}
/* verify private key */
if ( !SSL_CTX_check_private_key(ctx) )
{
fprintf(stderr, "Private key does not match the public certificate\n");
abort();
}
}
int OpenConnection(const char *hostname, int port)
{ int sd;
struct hostent *host;
struct sockaddr_in addr;
if ( (host = gethostbyname(hostname)) == NULL )
{
perror(hostname);
abort();
}
sd = socket(PF_INET, SOCK_STREAM, 0);
bzero(&addr, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_port = htons(port);
addr.sin_addr.s_addr = *(long*)(host->h_addr);
if ( connect(sd, (struct sockaddr*)&addr, sizeof(addr)) != 0 )
{
close(sd);
perror(hostname);
abort();
}
return sd;
}
SSL_CTX* InitCTX(void)
{ SSL_METHOD *method;
SSL_CTX *ctx;
OpenSSL_add_all_algorithms(); /* Load cryptos, et.al. */
SSL_load_error_strings(); /* Bring in and register error messages */
method = SSLv3_client_method(); /* Create new client-method instance */
ctx = SSL_CTX_new(method); /* Create new context */
if ( ctx == NULL )
{
ERR_print_errors_fp(stderr);
abort();
}
return ctx;
}
void ShowCerts(SSL* ssl)
{ X509 *cert;
char *line;
cert = SSL_get_peer_certificate(ssl); /* get the server's certificate */
if ( cert != NULL )
{
printf("Server certificates:\n");
line = X509_NAME_oneline(X509_get_subject_name(cert), 0, 0);
printf("Subject: %s\n", line);
free(line); /* free the malloc'ed string */
line = X509_NAME_oneline(X509_get_issuer_name(cert), 0, 0);
printf("Issuer: %s\n", line);
free(line); /* free the malloc'ed string */
X509_free(cert); /* free the malloc'ed certificate copy */
}
else
printf("No certificates.\n");
}
int main()
{ SSL_CTX *ctx;
int server;
SSL *ssl;
char buf[1024];
int bytes;
char hostname[]="127.0.0.1";
char portnum[]="5000";
char CertFile[] = "/home/myCA/cacert.pem";
char KeyFile[] = "/home/myCA/private/cakey.pem";
SSL_library_init();
ctx = InitCTX();
LoadCertificates(ctx, CertFile, KeyFile);
server = OpenConnection(hostname, atoi(portnum));
ssl = SSL_new(ctx); /* create new SSL connection state */
SSL_set_fd(ssl, server); /* attach the socket descriptor */
if ( SSL_connect(ssl) == FAIL ) /* perform the connection */
ERR_print_errors_fp(stderr);
else
{ char *msg = "Hello???";
printf("Connected with %s encryption\n", SSL_get_cipher(ssl));
ShowCerts(ssl); /* get any certs */
SSL_write(ssl, msg, strlen(msg)); /* encrypt & send message */
bytes = SSL_read(ssl, buf, sizeof(buf)); /* get reply & decrypt */
buf[bytes] = 0;
printf("Received: \"%s\"\n", buf);
SSL_free(ssl); /* release connection state */
}
close(server); /* close socket */
SSL_CTX_free(ctx); /* release context */
return 0;
}
And the server:
//SSL-Server.c
#include <errno.h>
#include <unistd.h>
#include <malloc.h>
#include <string.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <resolv.h>
#include "openssl/ssl.h"
#include "openssl/err.h"
#define FAIL -1
int OpenListener(int port)
{ int sd;
struct sockaddr_in addr;
sd = socket(PF_INET, SOCK_STREAM, 0);
bzero(&addr, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_port = htons(port);
addr.sin_addr.s_addr = INADDR_ANY;
if ( bind(sd, (struct sockaddr*)&addr, sizeof(addr)) != 0 )
{
perror("can't bind port");
abort();
}
if ( listen(sd, 10) != 0 )
{
perror("Can't configure listening port");
abort();
}
return sd;
}
SSL_CTX* InitServerCTX(void)
{ SSL_METHOD *method;
SSL_CTX *ctx;
OpenSSL_add_all_algorithms(); /* load & register all cryptos, etc. */
SSL_load_error_strings(); /* load all error messages */
method = SSLv3_server_method(); /* create new server-method instance */
ctx = SSL_CTX_new(method); /* create new context from method */
if ( ctx == NULL )
{
ERR_print_errors_fp(stderr);
abort();
}
return ctx;
}
void LoadCertificates(SSL_CTX* ctx, char* CertFile, char* KeyFile)
{
//New lines
if (SSL_CTX_load_verify_locations(ctx, CertFile, KeyFile) != 1)
ERR_print_errors_fp(stderr);
if (SSL_CTX_set_default_verify_paths(ctx) != 1)
ERR_print_errors_fp(stderr);
//End new lines
/* set the local certificate from CertFile */
if (SSL_CTX_use_certificate_file(ctx, CertFile, SSL_FILETYPE_PEM) <= 0)
{
ERR_print_errors_fp(stderr);
abort();
}
/* set the private key from KeyFile (may be the same as CertFile) */
if (SSL_CTX_use_PrivateKey_file(ctx, KeyFile, SSL_FILETYPE_PEM) <= 0)
{
ERR_print_errors_fp(stderr);
abort();
}
/* verify private key */
if (!SSL_CTX_check_private_key(ctx))
{
fprintf(stderr, "Private key does not match the public certificate\n");
abort();
}
//New lines - Force the client-side have a certificate
SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, NULL);
SSL_CTX_set_verify_depth(ctx, 4);
//End new lines
}
void ShowCerts(SSL* ssl)
{ X509 *cert;
char *line;
cert = SSL_get_peer_certificate(ssl); /* Get certificates (if available) */
if ( cert != NULL )
{
printf("Server certificates:\n");
line = X509_NAME_oneline(X509_get_subject_name(cert), 0, 0);
printf("Subject: %s\n", line);
free(line);
line = X509_NAME_oneline(X509_get_issuer_name(cert), 0, 0);
printf("Issuer: %s\n", line);
free(line);
X509_free(cert);
}
else
printf("No certificates.\n");
}
void Servlet(SSL* ssl) /* Serve the connection -- threadable */
{ char buf[1024];
char reply[1024];
int sd, bytes;
const char* HTMLecho="<html><body><pre>%s</pre></body></html>\n\n";
if ( SSL_accept(ssl) == FAIL ) /* do SSL-protocol accept */
ERR_print_errors_fp(stderr);
else
{
ShowCerts(ssl); /* get any certificates */
bytes = SSL_read(ssl, buf, sizeof(buf)); /* get request */
if ( bytes > 0 )
{
buf[bytes] = 0;
printf("Client msg: \"%s\"\n", buf);
sprintf(reply, HTMLecho, buf); /* construct reply */
SSL_write(ssl, reply, strlen(reply)); /* send reply */
}
else
ERR_print_errors_fp(stderr);
}
sd = SSL_get_fd(ssl); /* get socket connection */
SSL_free(ssl); /* release SSL state */
close(sd); /* close connection */
}
int main()
{ SSL_CTX *ctx;
int server;
char portnum[]="5000";
char CertFile[] = "/home/myCA/mycert.pem";
char KeyFile[] = "/home/myCA/mycert.pem";
SSL_library_init();
ctx = InitServerCTX(); /* initialize SSL */
LoadCertificates(ctx, CertFile, KeyFile); /* load certs */
server = OpenListener(atoi(portnum)); /* create server socket */
while (1)
{ struct sockaddr_in addr;
socklen_t len = sizeof(addr);
SSL *ssl;
int client = accept(server, (struct sockaddr*)&addr, &len); /* accept connection as usual */
printf("Connection: %s:%d\n",inet_ntoa(addr.sin_addr), ntohs(addr.sin_port));
ssl = SSL_new(ctx); /* get new SSL state with context */
SSL_set_fd(ssl, client); /* set connection socket to SSL state */
Servlet(ssl); /* service connection */
}
close(server); /* close server socket */
SSL_CTX_free(ctx); /* release context */
}
