I have created an client/server application to establish ssl session via certificates.
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 "ssl.h"
#include "err.h"
#include "crypto.h"
#include "apps.h"
#include "ssl.h"
#include "s_apps.h"
#define FAIL -1
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(int count, char *strings[])
{ SSL_CTX *ctx;
int server,cipherset;
SSL *ssl;
char buf[1024];
int bytes;
char *hostname, *portnum;
if ( count != 3 )
{
printf("usage: %s <hostname> <portnum>\n", strings[0]);
exit(0);
}
SSL_library_init();
hostname=strings[1];
portnum=strings[2];
ctx = InitCTX();
_cipherset=SSL_CTX_set_cipher_list(ctx,"OQSKEX-GENERIC");
server = OpenConnection(hostname, atoi(portnum));
ssl = SSL_new(ctx); /* create new SSL connection state /
SSL_set_fd(ssl, server); / attach the socket descriptor /
//cipherset=SSL_CTX_set_cipher_list(ctx,"SSL_kOQSKEX_SIDH_CLN16");
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;
}
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;
}
int isRoot()
{
if (getuid() != 0)
{
return 0;
}
else
{
return 1;
}
}
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)
{
/* 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();
}
}
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="
%s
\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(int count, char *strings[])
{ SSL_CTX *ctx;
int server;
char *portnum;
if(!isRoot())
{
printf("This program must be run as root/sudo user!!");
exit(0);
}
if ( count != 2 )
{
printf("Usage: %s <portnum>\n", strings[0]);
exit(0);
}
SSL_library_init();
portnum = strings[1];
ctx = InitServerCTX(); /* initialize SSL */
LoadCertificates(ctx, "mycert.pem", "mycert.pem"); /* 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 */
}
#######
compilation command for server.c:gcc -Wall -o server server.c -L/usr/local/ssl/lib/ -lssl -lcrypto -loqs -ldl
compilation command for client.c:gcc -Wall -o client client.c -L/usr/local/ssl/lib/ -lssl -lcrypto -loqs -ldl
(/usr/local/ssl/lib contain compiled libcrypto amd liboqs library).
to run server code:./server port-number
to run client code:./client server-ip port-number
i am using set_cipher_list function to set QS cipher text but when i run client side code it is showing error
ERROR:140135386150560:error:140830B5:SSL routines:ssl3_client_hello:no ciphers available:s3_clnt.c:841: