1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
9 *
10 * This software is licensed as described in the file COPYING, which
11 * you should have received as part of this distribution. The terms
12 * are also available at https://curl.se/docs/copyright.html.
13 *
14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15 * copies of the Software, and permit persons to whom the Software is
16 * furnished to do so, under the terms of the COPYING file.
17 *
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
20 *
21 ***************************************************************************/
22 /* <DESC>
23 * Uses the CURLINFO_TLS_SESSION data.
24 * </DESC>
25 */
26
27 /* Note that this example currently requires curl to be linked against
28 GnuTLS (and this program must also be linked against -lgnutls). */
29
30 #include <stdio.h>
31
32 #include <curl/curl.h>
33 #include <gnutls/gnutls.h>
34 #include <gnutls/x509.h>
35
36 static CURL *curl;
37
wrfu(void * ptr,size_t size,size_t nmemb,void * stream)38 static size_t wrfu(void *ptr, size_t size, size_t nmemb, void *stream)
39 {
40 const struct curl_tlssessioninfo *info;
41 unsigned int cert_list_size;
42 const gnutls_datum_t *chainp;
43 CURLcode res;
44
45 (void)stream;
46 (void)ptr;
47
48 res = curl_easy_getinfo(curl, CURLINFO_TLS_SESSION, &info);
49
50 if(!res) {
51 switch(info->backend) {
52 case CURLSSLBACKEND_GNUTLS:
53 /* info->internals is now the gnutls_session_t */
54 chainp = gnutls_certificate_get_peers(info->internals, &cert_list_size);
55 if((chainp) && (cert_list_size)) {
56 unsigned int i;
57
58 for(i = 0; i < cert_list_size; i++) {
59 gnutls_x509_crt_t cert;
60 gnutls_datum_t dn;
61
62 if(GNUTLS_E_SUCCESS == gnutls_x509_crt_init(&cert)) {
63 if(GNUTLS_E_SUCCESS ==
64 gnutls_x509_crt_import(cert, &chainp[i], GNUTLS_X509_FMT_DER)) {
65 if(GNUTLS_E_SUCCESS ==
66 gnutls_x509_crt_print(cert, GNUTLS_CRT_PRINT_FULL, &dn)) {
67 fprintf(stderr, "Certificate #%u: %.*s", i, dn.size, dn.data);
68
69 gnutls_free(dn.data);
70 }
71 }
72
73 gnutls_x509_crt_deinit(cert);
74 }
75 }
76 }
77 break;
78 case CURLSSLBACKEND_NONE:
79 default:
80 break;
81 }
82 }
83
84 return size * nmemb;
85 }
86
main(void)87 int main(void)
88 {
89 curl_global_init(CURL_GLOBAL_DEFAULT);
90
91 curl = curl_easy_init();
92 if(curl) {
93 curl_easy_setopt(curl, CURLOPT_URL, "https://www.example.com/");
94
95 curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, wrfu);
96
97 curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
98 curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
99
100 curl_easy_setopt(curl, CURLOPT_VERBOSE, 0L);
101
102 (void) curl_easy_perform(curl);
103
104 curl_easy_cleanup(curl);
105 }
106
107 curl_global_cleanup();
108
109 return 0;
110 }
111