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/* This example code is placed in the public domain. */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <gnutls/gnutls.h>
#include <gnutls/x509.h>
#include <gnutls/abstract.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
/* A TLS client that loads the certificate and key.
*/
#define MAX_BUF 1024
#define MSG "GET / HTTP/1.0\r\n\r\n"
#define CERT_FILE "cert.pem"
#define KEY_FILE "key.pem"
#define CAFILE "/etc/ssl/certs/ca-certificates.crt"
extern int tcp_connect (void);
extern void tcp_close (int sd);
static int
cert_callback (gnutls_session_t session,
const gnutls_datum_t * req_ca_rdn, int nreqs,
const gnutls_pk_algorithm_t * sign_algos,
int sign_algos_length, gnutls_pcert_st ** pcert,
unsigned int *pcert_length, gnutls_privkey_t * pkey);
gnutls_pcert_st pcrt;
gnutls_privkey_t key;
/* Load the certificate and the private key.
*/
static void
load_keys (void)
{
int ret;
gnutls_datum_t data;
ret = gnutls_load_file (CERT_FILE, &data);
if (ret < 0)
{
fprintf (stderr, "*** Error loading certificate file.\n");
exit (1);
}
ret = gnutls_pcert_import_x509_raw (&pcrt, &data, GNUTLS_X509_FMT_PEM, 0);
if (ret < 0)
{
fprintf (stderr, "*** Error loading certificate file: %s\n",
gnutls_strerror (ret));
exit (1);
}
gnutls_free(data.data);
ret = gnutls_load_file (KEY_FILE, &data);
if (ret < 0)
{
fprintf (stderr, "*** Error loading key file.\n");
exit (1);
}
gnutls_privkey_init (&key);
ret = gnutls_privkey_import_x509_raw (key, &data, GNUTLS_X509_FMT_PEM, NULL, 0);
if (ret < 0)
{
fprintf (stderr, "*** Error loading key file: %s\n",
gnutls_strerror (ret));
exit (1);
}
gnutls_free(data.data);
}
int
main (void)
{
int ret, sd, ii;
gnutls_session_t session;
gnutls_priority_t priorities_cache;
char buffer[MAX_BUF + 1];
gnutls_certificate_credentials_t xcred;
/* Allow connections to servers that have OpenPGP keys as well.
*/
gnutls_global_init ();
load_keys ();
/* X509 stuff */
gnutls_certificate_allocate_credentials (&xcred);
/* priorities */
gnutls_priority_init (&priorities_cache, "NORMAL", NULL);
/* sets the trusted cas file
*/
gnutls_certificate_set_x509_trust_file (xcred, CAFILE, GNUTLS_X509_FMT_PEM);
gnutls_certificate_set_retrieve_function2 (xcred, cert_callback);
/* Initialize TLS session
*/
gnutls_init (&session, GNUTLS_CLIENT);
/* Use default priorities */
gnutls_priority_set (session, priorities_cache);
/* put the x509 credentials to the current session
*/
gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, xcred);
/* connect to the peer
*/
sd = tcp_connect ();
gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) sd);
/* Perform the TLS handshake
*/
ret = gnutls_handshake (session);
if (ret < 0)
{
fprintf (stderr, "*** Handshake failed\n");
gnutls_perror (ret);
goto end;
}
else
{
printf ("- Handshake was completed\n");
}
gnutls_record_send (session, MSG, strlen (MSG));
ret = gnutls_record_recv (session, buffer, MAX_BUF);
if (ret == 0)
{
printf ("- Peer has closed the TLS connection\n");
goto end;
}
else if (ret < 0)
{
fprintf (stderr, "*** Error: %s\n", gnutls_strerror (ret));
goto end;
}
printf ("- Received %d bytes: ", ret);
for (ii = 0; ii < ret; ii++)
{
fputc (buffer[ii], stdout);
}
fputs ("\n", stdout);
gnutls_bye (session, GNUTLS_SHUT_RDWR);
end:
tcp_close (sd);
gnutls_deinit (session);
gnutls_certificate_free_credentials (xcred);
gnutls_priority_deinit (priorities_cache);
gnutls_global_deinit ();
return 0;
}
/* This callback should be associated with a session by calling
* gnutls_certificate_client_set_retrieve_function( session, cert_callback),
* before a handshake.
*/
static int
cert_callback (gnutls_session_t session,
const gnutls_datum_t * req_ca_rdn, int nreqs,
const gnutls_pk_algorithm_t * sign_algos,
int sign_algos_length, gnutls_pcert_st ** pcert,
unsigned int *pcert_length, gnutls_privkey_t * pkey)
{
char issuer_dn[256];
int i, ret;
size_t len;
gnutls_certificate_type_t type;
/* Print the server's trusted CAs
*/
if (nreqs > 0)
printf ("- Server's trusted authorities:\n");
else
printf ("- Server did not send us any trusted authorities names.\n");
/* print the names (if any) */
for (i = 0; i < nreqs; i++)
{
len = sizeof (issuer_dn);
ret = gnutls_x509_rdn_get (&req_ca_rdn[i], issuer_dn, &len);
if (ret >= 0)
{
printf (" [%d]: ", i);
printf ("%s\n", issuer_dn);
}
}
/* Select a certificate and return it.
* The certificate must be of any of the "sign algorithms"
* supported by the server.
*/
type = gnutls_certificate_type_get (session);
if (type == GNUTLS_CRT_X509)
{
*pcert_length = 1;
*pcert = &pcrt;
*pkey = key;
}
else
{
return -1;
}
return 0;
}
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