summaryrefslogtreecommitdiff
path: root/doc/examples/ex-serv-x509.c
blob: df57207140248587c6b47997196005cddb6f4d73 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <string.h>
#include <unistd.h>
#include <gnutls/gnutls.h>
#include <assert.h>

#define KEYFILE "key.pem"
#define CERTFILE "cert.pem"
#define CAFILE "/etc/ssl/certs/ca-certificates.crt"
#define CRLFILE "crl.pem"

#define CHECK(x) assert((x)>=0)
#define LOOP_CHECK(rval, cmd) \
        do { \
                rval = cmd; \
        } while(rval == GNUTLS_E_AGAIN || rval == GNUTLS_E_INTERRUPTED)

/* The OCSP status file contains up to date information about revocation
 * of the server's certificate. That can be periodically be updated
 * using:
 * $ ocsptool --ask --load-cert your_cert.pem --load-issuer your_issuer.pem
 *            --load-signer your_issuer.pem --outfile ocsp-status.der
 */
#define OCSP_STATUS_FILE "ocsp-status.der"

/* This is a sample TLS 1.0 echo server, using X.509 authentication and
 * OCSP stapling support.
 */

#define MAX_BUF 1024
#define PORT 5556               /* listen to 5556 port */

int main(void)
{
        int listen_sd;
        int sd, ret;
        gnutls_certificate_credentials_t x509_cred;
        gnutls_priority_t priority_cache;
        struct sockaddr_in sa_serv;
        struct sockaddr_in sa_cli;
        socklen_t client_len;
        char topbuf[512];
        gnutls_session_t session;
        char buffer[MAX_BUF + 1];
        int optval = 1;

        /* for backwards compatibility with gnutls < 3.3.0 */
        CHECK(gnutls_global_init());

        CHECK(gnutls_certificate_allocate_credentials(&x509_cred));

        CHECK(gnutls_certificate_set_x509_trust_file(x509_cred, CAFILE,
                                                     GNUTLS_X509_FMT_PEM));

        CHECK(gnutls_certificate_set_x509_crl_file(x509_cred, CRLFILE,
                                                   GNUTLS_X509_FMT_PEM));

        /* The following code sets the certificate key pair as well as, 
         * an OCSP response which corresponds to it. It is possible
         * to set multiple key-pairs and multiple OCSP status responses
         * (the latter since 3.5.6). See the manual pages of the individual
         * functions for more information.
         */
        CHECK(gnutls_certificate_set_x509_key_file(x509_cred, CERTFILE,
                                                   KEYFILE,
                                                   GNUTLS_X509_FMT_PEM));

        CHECK(gnutls_certificate_set_ocsp_status_request_file(x509_cred,
                                                              OCSP_STATUS_FILE,
                                                              0));

        CHECK(gnutls_priority_init(&priority_cache, NULL, NULL));

        /* Instead of the default options as shown above one could specify
         * additional options such as server precedence in ciphersuite selection
         * as follows:
         * gnutls_priority_init2(&priority_cache,
         *                       "%SERVER_PRECEDENCE",
         *                       NULL, GNUTLS_PRIORITY_INIT_DEF_APPEND);
	 */

#if GNUTLS_VERSION_NUMBER >= 0x030506
        /* only available since GnuTLS 3.5.6, on previous versions see
         * gnutls_certificate_set_dh_params(). */
        gnutls_certificate_set_known_dh_params(x509_cred, GNUTLS_SEC_PARAM_MEDIUM);
#endif

        /* Socket operations
         */
        listen_sd = socket(AF_INET, SOCK_STREAM, 0);

        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(PORT); /* Server Port number */

        setsockopt(listen_sd, SOL_SOCKET, SO_REUSEADDR, (void *) &optval,
                   sizeof(int));

        bind(listen_sd, (struct sockaddr *) &sa_serv, sizeof(sa_serv));

        listen(listen_sd, 1024);

        printf("Server ready. Listening to port '%d'.\n\n", PORT);

        client_len = sizeof(sa_cli);
        for (;;) {
                CHECK(gnutls_init(&session, GNUTLS_SERVER));
                CHECK(gnutls_priority_set(session, priority_cache));
                CHECK(gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE,
                                             x509_cred));

                /* We don't request any certificate from the client.
                 * If we did we would need to verify it. One way of
                 * doing that is shown in the "Verifying a certificate"
                 * example.
                 */
                gnutls_certificate_server_set_request(session,
                                                      GNUTLS_CERT_IGNORE);
                gnutls_handshake_set_timeout(session,
                                             GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);

                sd = accept(listen_sd, (struct sockaddr *) &sa_cli,
                            &client_len);

                printf("- connection from %s, port %d\n",
                       inet_ntop(AF_INET, &sa_cli.sin_addr, topbuf,
                                 sizeof(topbuf)), ntohs(sa_cli.sin_port));

                gnutls_transport_set_int(session, sd);

                LOOP_CHECK(ret, gnutls_handshake(session));
                if (ret < 0) {
                        close(sd);
                        gnutls_deinit(session);
                        fprintf(stderr,
                                "*** Handshake has failed (%s)\n\n",
                                gnutls_strerror(ret));
                        continue;
                }
                printf("- Handshake was completed\n");

                /* see the Getting peer's information example */
                /* print_info(session); */

                for (;;) {
                        LOOP_CHECK(ret, gnutls_record_recv(session, buffer, MAX_BUF));

                        if (ret == 0) {
                                printf
                                    ("\n- Peer has closed the GnuTLS connection\n");
                                break;
                        } else if (ret < 0
                                   && gnutls_error_is_fatal(ret) == 0) {
                                fprintf(stderr, "*** Warning: %s\n",
                                        gnutls_strerror(ret));
                        } else if (ret < 0) {
                                fprintf(stderr, "\n*** Received corrupted "
                                        "data(%d). Closing the connection.\n\n",
                                        ret);
                                break;
                        } else if (ret > 0) {
                                /* echo data back to the client
                                 */
                                CHECK(gnutls_record_send(session, buffer, ret));
                        }
                }
                printf("\n");
                /* do not wait for the peer to close the connection.
                 */
                LOOP_CHECK(ret, gnutls_bye(session, GNUTLS_SHUT_WR));

                close(sd);
                gnutls_deinit(session);

        }
        close(listen_sd);

        gnutls_certificate_free_credentials(x509_cred);
        gnutls_priority_deinit(priority_cache);

        gnutls_global_deinit();

        return 0;

}