4
* This file demonstrates how to use Avahi's core API, this is
5
* the embeddable mDNS stack for embedded applications.
1
/* -*- coding: utf-8 -*- */
3
* Mandos client - get and decrypt data from a Mandos server
7
* End user applications should *not* use this API and should use
8
* the D-Bus or C APIs, please see
9
* client-browse-services.c and glib-integration.c
11
* I repeat, you probably do *not* want to use this example.
5
* This program is partly derived from an example program for an Avahi
6
* service browser, downloaded from
7
* <http://avahi.org/browser/examples/core-browse-services.c>. This
8
* includes the following functions: "resolve_callback",
9
* "browse_callback", and parts of "main".
11
* Everything else is Copyright © 2007-2008 Teddy Hogeborn and Björn
14
* This program is free software: you can redistribute it and/or
15
* modify it under the terms of the GNU General Public License as
16
* published by the Free Software Foundation, either version 3 of the
17
* License, or (at your option) any later version.
19
* This program is distributed in the hope that it will be useful, but
20
* WITHOUT ANY WARRANTY; without even the implied warranty of
21
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22
* General Public License for more details.
24
* You should have received a copy of the GNU General Public License
25
* along with this program. If not, see
26
* <http://www.gnu.org/licenses/>.
28
* Contact the authors at <https://www.fukt.bsnet.se/~belorn/> and
29
* <https://www.fukt.bsnet.se/~teddy/>.
15
This file is part of avahi.
17
avahi is free software; you can redistribute it and/or modify it
18
under the terms of the GNU Lesser General Public License as
19
published by the Free Software Foundation; either version 2.1 of the
20
License, or (at your option) any later version.
22
avahi is distributed in the hope that it will be useful, but WITHOUT
23
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
24
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
25
Public License for more details.
27
You should have received a copy of the GNU Lesser General Public
28
License along with avahi; if not, write to the Free Software
29
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
32
#define _FORTIFY_SOURCE 2
33
34
#define _LARGEFILE_SOURCE
34
35
#define _FILE_OFFSET_BITS 64
47
48
#include <avahi-common/error.h>
49
50
//mandos client part
50
#include <sys/types.h> /* socket(), setsockopt(), inet_pton() */
51
#include <sys/socket.h> /* socket(), setsockopt(), struct sockaddr_in6, struct in6_addr, inet_pton() */
52
#include <gnutls/gnutls.h> /* ALL GNUTLS STUFF */
53
#include <gnutls/openpgp.h> /* gnutls with openpgp stuff */
51
#include <sys/types.h> /* socket(), inet_pton() */
52
#include <sys/socket.h> /* socket(), struct sockaddr_in6,
53
struct in6_addr, inet_pton() */
54
#include <gnutls/gnutls.h> /* All GnuTLS stuff */
55
#include <gnutls/openpgp.h> /* GnuTLS with openpgp stuff */
55
57
#include <unistd.h> /* close() */
56
58
#include <netinet/in.h>
79
85
} encrypted_session;
82
ssize_t gpg_packet_decrypt (char *packet, size_t packet_size, char **new_packet, char *homedir){
88
ssize_t pgp_packet_decrypt (char *packet, size_t packet_size,
89
char **new_packet, const char *homedir){
83
90
gpgme_data_t dh_crypto, dh_plain;
87
size_t new_packet_capacity = 0;
88
size_t new_packet_length = 0;
94
ssize_t new_packet_capacity = 0;
95
ssize_t new_packet_length = 0;
89
96
gpgme_engine_info_t engine_info;
99
fprintf(stderr, "Trying to decrypt OpenPGP packet\n");
92
103
gpgme_check_version(NULL);
93
104
gpgme_engine_check_version(GPGME_PROTOCOL_OpenPGP);
139
/* Decrypt data from the FILE pointer to the plaintext data buffer */
150
/* Decrypt data from the FILE pointer to the plaintext data
140
152
rc = gpgme_op_decrypt(ctx, dh_crypto, dh_plain);
141
153
if (rc != GPG_ERR_NO_ERROR){
142
154
fprintf(stderr, "bad gpgme_op_decrypt: %s: %s\n",
143
155
gpgme_strsource(rc), gpgme_strerror(rc));
160
fprintf(stderr, "Decryption of OpenPGP packet succeeded\n");
164
gpgme_decrypt_result_t result;
165
result = gpgme_op_decrypt_result(ctx);
167
fprintf(stderr, "gpgme_op_decrypt_result failed\n");
169
fprintf(stderr, "Unsupported algorithm: %s\n",
170
result->unsupported_algorithm);
171
fprintf(stderr, "Wrong key usage: %d\n",
172
result->wrong_key_usage);
173
if(result->file_name != NULL){
174
fprintf(stderr, "File name: %s\n", result->file_name);
176
gpgme_recipient_t recipient;
177
recipient = result->recipients;
179
while(recipient != NULL){
180
fprintf(stderr, "Public key algorithm: %s\n",
181
gpgme_pubkey_algo_name(recipient->pubkey_algo));
182
fprintf(stderr, "Key ID: %s\n", recipient->keyid);
183
fprintf(stderr, "Secret key available: %s\n",
184
recipient->status == GPG_ERR_NO_SECKEY
186
recipient = recipient->next;
147
/* gpgme_decrypt_result_t result; */
148
/* result = gpgme_op_decrypt_result(ctx); */
149
/* fprintf(stderr, "Unsupported algorithm: %s\n", result->unsupported_algorithm); */
150
/* fprintf(stderr, "Wrong key usage: %d\n", result->wrong_key_usage); */
151
/* if(result->file_name != NULL){ */
152
/* fprintf(stderr, "File name: %s\n", result->file_name); */
154
/* gpgme_recipient_t recipient; */
155
/* recipient = result->recipients; */
157
/* while(recipient != NULL){ */
158
/* fprintf(stderr, "Public key algorithm: %s\n", */
159
/* gpgme_pubkey_algo_name(recipient->pubkey_algo)); */
160
/* fprintf(stderr, "Key ID: %s\n", recipient->keyid); */
161
/* fprintf(stderr, "Secret key available: %s\n", */
162
/* recipient->status == GPG_ERR_NO_SECKEY ? "No" : "Yes"); */
163
/* recipient = recipient->next; */
167
192
/* Delete the GPGME FILE pointer cryptotext data buffer */
168
193
gpgme_data_release(dh_crypto);
170
195
/* Seek back to the beginning of the GPGME plaintext data buffer */
171
gpgme_data_seek(dh_plain, 0, SEEK_SET);
196
gpgme_data_seek(dh_plain, (off_t) 0, SEEK_SET);
175
200
if (new_packet_length + BUFFER_SIZE > new_packet_capacity){
176
*new_packet = realloc(*new_packet, new_packet_capacity + BUFFER_SIZE);
201
*new_packet = realloc(*new_packet,
202
(unsigned int)new_packet_capacity
177
204
if (*new_packet == NULL){
178
205
perror("realloc");
194
221
new_packet_length += ret;
197
/* Delete the GPGME plaintext data buffer */
224
/* FIXME: check characters before printing to screen so to not print
225
terminal control characters */
227
/* fprintf(stderr, "decrypted password is: "); */
228
/* fwrite(*new_packet, 1, new_packet_length, stderr); */
229
/* fprintf(stderr, "\n"); */
232
/* Delete the GPGME plaintext data buffer */
198
233
gpgme_data_release(dh_plain);
199
234
return new_packet_length;
254
fprintf(stderr, "Initializing GnuTLS\n");
217
257
if ((ret = gnutls_global_init ())
218
258
!= GNUTLS_E_SUCCESS) {
219
259
fprintf (stderr, "global_init: %s\n", safer_gnutls_strerror(ret));
223
/* Uncomment to enable full debuggin on the gnutls library */
224
/* gnutls_global_set_log_level(11); */
225
/* gnutls_global_set_log_function(debuggnutls); */
264
gnutls_global_set_log_level(11);
265
gnutls_global_set_log_function(debuggnutls);
228
268
/* openpgp credentials */
229
269
if ((ret = gnutls_certificate_allocate_credentials (&es->cred))
230
270
!= GNUTLS_E_SUCCESS) {
231
fprintf (stderr, "memory error: %s\n", safer_gnutls_strerror(ret));
271
fprintf (stderr, "memory error: %s\n",
272
safer_gnutls_strerror(ret));
277
fprintf(stderr, "Attempting to use OpenPGP certificate %s"
278
" and keyfile %s as GnuTLS credentials\n", CERTFILE,
235
282
ret = gnutls_certificate_set_openpgp_key_file
236
283
(es->cred, CERTFILE, KEYFILE, GNUTLS_OPENPGP_FMT_BASE64);
237
284
if (ret != GNUTLS_E_SUCCESS) {
239
(stderr, "Error[%d] while reading the OpenPGP key pair ('%s', '%s')\n",
286
(stderr, "Error[%d] while reading the OpenPGP key pair ('%s',"
240
288
ret, CERTFILE, KEYFILE);
241
289
fprintf(stdout, "The Error is: %s\n",
242
290
safer_gnutls_strerror(ret));
246
//Gnutls server initialization
294
//GnuTLS server initialization
247
295
if ((ret = gnutls_dh_params_init (&es->dh_params))
248
296
!= GNUTLS_E_SUCCESS) {
249
297
fprintf (stderr, "Error in dh parameter initialization: %s\n",
250
298
safer_gnutls_strerror(ret));
254
302
if ((ret = gnutls_dh_params_generate2 (es->dh_params, DH_BITS))
255
303
!= GNUTLS_E_SUCCESS) {
256
304
fprintf (stderr, "Error in prime generation: %s\n",
257
305
safer_gnutls_strerror(ret));
261
309
gnutls_certificate_set_dh_params (es->cred, es->dh_params);
263
// Gnutls session creation
311
// GnuTLS session creation
264
312
if ((ret = gnutls_init (&es->session, GNUTLS_SERVER))
265
313
!= GNUTLS_E_SUCCESS){
266
fprintf(stderr, "Error in gnutls session initialization: %s\n",
314
fprintf(stderr, "Error in GnuTLS session initialization: %s\n",
267
315
safer_gnutls_strerror(ret));
270
318
if ((ret = gnutls_priority_set_direct (es->session, "NORMAL", &err))
271
319
!= GNUTLS_E_SUCCESS) {
272
320
fprintf(stderr, "Syntax error at: %s\n", err);
273
fprintf(stderr, "Gnutls error: %s\n",
321
fprintf(stderr, "GnuTLS error: %s\n",
274
322
safer_gnutls_strerror(ret));
278
326
if ((ret = gnutls_credentials_set
279
327
(es->session, GNUTLS_CRD_CERTIFICATE, es->cred))
280
328
!= GNUTLS_E_SUCCESS) {
282
330
safer_gnutls_strerror(ret));
286
334
/* ignore client certificate if any. */
287
gnutls_certificate_server_set_request (es->session, GNUTLS_CERT_IGNORE);
335
gnutls_certificate_server_set_request (es->session,
289
338
gnutls_dh_set_prime_bits (es->session, DH_BITS);
294
void empty_log(AvahiLogLevel level, const char *txt){}
343
void empty_log(__attribute__((unused)) AvahiLogLevel level,
344
__attribute__((unused)) const char *txt){}
296
int start_mandos_communcation(char *ip, uint16_t port){
346
int start_mandos_communication(const char *ip, uint16_t port,
347
unsigned int if_index){
298
349
struct sockaddr_in6 to;
299
struct in6_addr ip_addr;
300
350
encrypted_session es;
301
351
char *buffer = NULL;
302
352
char *decrypted_buffer;
303
353
size_t buffer_length = 0;
304
354
size_t buffer_capacity = 0;
305
355
ssize_t decrypted_buffer_size;
358
char interface[IF_NAMESIZE];
361
fprintf(stderr, "Setting up a tcp connection to %s\n", ip);
309
364
tcp_sd = socket(PF_INET6, SOCK_STREAM, 0);
315
ret = setsockopt(tcp_sd, SOL_SOCKET, SO_BINDTODEVICE, "eth0", 5);
317
perror("setsockopt bindtodevice");
370
if(if_indextoname(if_index, interface) == NULL){
372
perror("if_indextoname");
321
memset(&to,0,sizeof(to));
378
fprintf(stderr, "Binding to interface %s\n", interface);
381
memset(&to,0,sizeof(to)); /* Spurious warning */
322
382
to.sin6_family = AF_INET6;
323
ret = inet_pton(AF_INET6, ip, &ip_addr);
383
ret = inet_pton(AF_INET6, ip, &to.sin6_addr);
325
385
perror("inet_pton");
348
gnutls_transport_set_ptr (es.session, (gnutls_transport_ptr_t) tcp_sd);
412
gnutls_transport_set_ptr (es.session,
413
(gnutls_transport_ptr_t) tcp_sd);
416
fprintf(stderr, "Establishing TLS session with %s\n", ip);
350
419
ret = gnutls_handshake (es.session);
352
421
if (ret != GNUTLS_E_SUCCESS){
353
fprintf(stderr, "\n*** Handshake failed ***\n");
423
fprintf(stderr, "\n*** Handshake failed ***\n");
430
//Retrieve OpenPGP packet that contains the wanted password
433
fprintf(stderr, "Retrieving pgp encrypted password from %s\n",
361
438
if (buffer_length + BUFFER_SIZE > buffer_capacity){
362
439
buffer = realloc(buffer, buffer_capacity + BUFFER_SIZE);
390
fprintf(stderr, "Unknown error while reading data from encrypted session with mandos server\n");
467
fprintf(stderr, "Unknown error while reading data from"
468
" encrypted session with mandos server\n");
392
470
gnutls_bye (es.session, GNUTLS_SHUT_RDWR);
396
buffer_length += ret;
474
buffer_length += (size_t) ret;
400
478
if (buffer_length > 0){
401
if ((decrypted_buffer_size = gpg_packet_decrypt(buffer, buffer_length, &decrypted_buffer, CERT_ROOT)) == 0){
479
decrypted_buffer_size = pgp_packet_decrypt(buffer,
483
if (decrypted_buffer_size >= 0){
484
while(written < decrypted_buffer_size){
485
ret = (int)fwrite (decrypted_buffer + written, 1,
486
(size_t)decrypted_buffer_size - written,
488
if(ret == 0 and ferror(stdout)){
490
fprintf(stderr, "Error writing encrypted data: %s\n",
496
written += (size_t)ret;
498
free(decrypted_buffer);
404
fwrite (decrypted_buffer, 1, decrypted_buffer_size, stdout);
405
free(decrypted_buffer);
507
fprintf(stderr, "Closing TLS session\n");
412
511
gnutls_bye (es.session, GNUTLS_SHUT_RDWR);
432
531
const char *host_name,
433
532
const AvahiAddress *address,
435
AvahiStringList *txt,
436
AvahiLookupResultFlags flags,
534
AVAHI_GCC_UNUSED AvahiStringList *txt,
535
AVAHI_GCC_UNUSED AvahiLookupResultFlags flags,
437
536
AVAHI_GCC_UNUSED void* userdata) {
441
/* Called whenever a service has been resolved successfully or timed out */
444
case AVAHI_RESOLVER_FAILURE:
445
fprintf(stderr, "(Resolver) Failed to resolve service '%s' of type '%s' in domain '%s': %s\n", name, type, domain, avahi_strerror(avahi_server_errno(server)));
448
case AVAHI_RESOLVER_FOUND: {
449
char ip[AVAHI_ADDRESS_STR_MAX];
450
avahi_address_snprint(ip, sizeof(ip), address);
451
int ret = start_mandos_communcation(ip, port);
538
assert(r); /* Spurious warning */
540
/* Called whenever a service has been resolved successfully or
545
case AVAHI_RESOLVER_FAILURE:
546
fprintf(stderr, "(Resolver) Failed to resolve service '%s' of"
547
" type '%s' in domain '%s': %s\n", name, type, domain,
548
avahi_strerror(avahi_server_errno(server)));
551
case AVAHI_RESOLVER_FOUND:
553
char ip[AVAHI_ADDRESS_STR_MAX];
554
avahi_address_snprint(ip, sizeof(ip), address);
556
fprintf(stderr, "Mandos server \"%s\" found on %s (%s) on"
557
" port %d\n", name, host_name, ip, port);
559
int ret = start_mandos_communication(ip, port,
560
(unsigned int) interface);
459
avahi_s_service_resolver_free(r);
566
avahi_s_service_resolver_free(r);
462
569
static void browse_callback(
471
578
void* userdata) {
473
580
AvahiServer *s = userdata;
476
/* Called whenever a new services becomes available on the LAN or is removed from the LAN */
581
assert(b); /* Spurious warning */
583
/* Called whenever a new services becomes available on the LAN or
584
is removed from the LAN */
480
case AVAHI_BROWSER_FAILURE:
482
fprintf(stderr, "(Browser) %s\n", avahi_strerror(avahi_server_errno(server)));
483
avahi_simple_poll_quit(simple_poll);
486
case AVAHI_BROWSER_NEW:
487
/* We ignore the returned resolver object. In the callback
488
function we free it. If the server is terminated before
489
the callback function is called the server will free
490
the resolver for us. */
492
if (!(avahi_s_service_resolver_new(s, interface, protocol, name, type, domain, AVAHI_PROTO_INET6, 0, resolve_callback, s)))
493
fprintf(stderr, "Failed to resolve service '%s': %s\n", name, avahi_strerror(avahi_server_errno(s)));
497
case AVAHI_BROWSER_REMOVE:
500
case AVAHI_BROWSER_ALL_FOR_NOW:
501
case AVAHI_BROWSER_CACHE_EXHAUSTED:
588
case AVAHI_BROWSER_FAILURE:
590
fprintf(stderr, "(Browser) %s\n",
591
avahi_strerror(avahi_server_errno(server)));
592
avahi_simple_poll_quit(simple_poll);
595
case AVAHI_BROWSER_NEW:
596
/* We ignore the returned resolver object. In the callback
597
function we free it. If the server is terminated before
598
the callback function is called the server will free
599
the resolver for us. */
601
if (!(avahi_s_service_resolver_new(s, interface, protocol, name,
603
AVAHI_PROTO_INET6, 0,
604
resolve_callback, s)))
605
fprintf(stderr, "Failed to resolve service '%s': %s\n", name,
606
avahi_strerror(avahi_server_errno(s)));
609
case AVAHI_BROWSER_REMOVE:
612
case AVAHI_BROWSER_ALL_FOR_NOW:
613
case AVAHI_BROWSER_CACHE_EXHAUSTED:
507
619
AvahiServerConfig config;
508
620
AvahiSServiceBrowser *sb = NULL;
512
avahi_set_log_function(empty_log);
623
int returncode = EXIT_SUCCESS;
624
const char *interface = "eth0";
627
static struct option long_options[] = {
628
{"debug", no_argument, (int *)&debug, 1},
629
{"interface", required_argument, 0, 'i'},
632
int option_index = 0;
633
ret = getopt_long (argc, argv, "i:", long_options,
652
avahi_set_log_function(empty_log);
514
655
/* Initialize the psuedo-RNG */
656
srand((unsigned int) time(NULL));
517
658
/* Allocate main loop object */
518
659
if (!(simple_poll = avahi_simple_poll_new())) {
519
660
fprintf(stderr, "Failed to create simple poll object.\n");
523
665
/* Do not publish any local records */
527
669
config.publish_workstation = 0;
528
670
config.publish_domain = 0;
530
/* /\* Set a unicast DNS server for wide area DNS-SD *\/ */
531
/* avahi_address_parse("193.11.177.11", AVAHI_PROTO_UNSPEC, &config.wide_area_servers[0]); */
532
/* config.n_wide_area_servers = 1; */
533
/* config.enable_wide_area = 1; */
535
672
/* Allocate a new server */
536
server = avahi_server_new(avahi_simple_poll_get(simple_poll), &config, NULL, NULL, &error);
673
server = avahi_server_new(avahi_simple_poll_get(simple_poll),
674
&config, NULL, NULL, &error);
538
676
/* Free the configuration data */
539
677
avahi_server_config_free(&config);
541
/* Check wether creating the server object succeeded */
679
/* Check if creating the server object succeeded */
543
fprintf(stderr, "Failed to create server: %s\n", avahi_strerror(error));
681
fprintf(stderr, "Failed to create server: %s\n",
682
avahi_strerror(error));
683
returncode = EXIT_FAILURE;
547
687
/* Create the service browser */
548
if (!(sb = avahi_s_service_browser_new(server, if_nametoindex("eth0"), AVAHI_PROTO_INET6, "_mandos._tcp", NULL, 0, browse_callback, server))) {
549
fprintf(stderr, "Failed to create service browser: %s\n", avahi_strerror(avahi_server_errno(server)));
688
sb = avahi_s_service_browser_new(server,
690
if_nametoindex(interface),
692
"_mandos._tcp", NULL, 0,
693
browse_callback, server);
695
fprintf(stderr, "Failed to create service browser: %s\n",
696
avahi_strerror(avahi_server_errno(server)));
697
returncode = EXIT_FAILURE;
553
701
/* Run the main loop */
704
fprintf(stderr, "Starting avahi loop search\n");
554
707
avahi_simple_poll_loop(simple_poll);
712
fprintf(stderr, "%s exiting\n", argv[0]);
560
715
/* Cleanup things */