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
84
} encrypted_session;
82
ssize_t gpg_packet_decrypt (char *packet, size_t packet_size, char **new_packet, char *homedir){
87
ssize_t pgp_packet_decrypt (char *packet, size_t packet_size,
88
char **new_packet, const char *homedir){
83
89
gpgme_data_t dh_crypto, dh_plain;
87
size_t new_packet_capacity = 0;
88
size_t new_packet_length = 0;
93
ssize_t new_packet_capacity = 0;
94
ssize_t new_packet_length = 0;
89
95
gpgme_engine_info_t engine_info;
98
fprintf(stderr, "Trying to decrypt OpenPGP packet\n");
92
102
gpgme_check_version(NULL);
93
gpgme_engine_check_version(GPGME_PROTOCOL_OpenPGP);
103
rc = gpgme_engine_check_version(GPGME_PROTOCOL_OpenPGP);
104
if (rc != GPG_ERR_NO_ERROR){
105
fprintf(stderr, "bad gpgme_engine_check_version: %s: %s\n",
106
gpgme_strsource(rc), gpgme_strerror(rc));
95
110
/* Set GPGME home directory */
96
111
rc = gpgme_get_engine_info (&engine_info);
139
/* Decrypt data from the FILE pointer to the plaintext data buffer */
154
/* Decrypt data from the FILE pointer to the plaintext data
140
156
rc = gpgme_op_decrypt(ctx, dh_crypto, dh_plain);
141
157
if (rc != GPG_ERR_NO_ERROR){
142
158
fprintf(stderr, "bad gpgme_op_decrypt: %s: %s\n",
143
159
gpgme_strsource(rc), gpgme_strerror(rc));
164
fprintf(stderr, "Decryption of OpenPGP packet succeeded\n");
168
gpgme_decrypt_result_t result;
169
result = gpgme_op_decrypt_result(ctx);
171
fprintf(stderr, "gpgme_op_decrypt_result failed\n");
173
fprintf(stderr, "Unsupported algorithm: %s\n",
174
result->unsupported_algorithm);
175
fprintf(stderr, "Wrong key usage: %d\n",
176
result->wrong_key_usage);
177
if(result->file_name != NULL){
178
fprintf(stderr, "File name: %s\n", result->file_name);
180
gpgme_recipient_t recipient;
181
recipient = result->recipients;
183
while(recipient != NULL){
184
fprintf(stderr, "Public key algorithm: %s\n",
185
gpgme_pubkey_algo_name(recipient->pubkey_algo));
186
fprintf(stderr, "Key ID: %s\n", recipient->keyid);
187
fprintf(stderr, "Secret key available: %s\n",
188
recipient->status == GPG_ERR_NO_SECKEY
190
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
196
/* Delete the GPGME FILE pointer cryptotext data buffer */
168
197
gpgme_data_release(dh_crypto);
170
199
/* Seek back to the beginning of the GPGME plaintext data buffer */
171
gpgme_data_seek(dh_plain, 0, SEEK_SET);
200
gpgme_data_seek(dh_plain, (off_t) 0, SEEK_SET);
175
204
if (new_packet_length + BUFFER_SIZE > new_packet_capacity){
176
*new_packet = realloc(*new_packet, new_packet_capacity + BUFFER_SIZE);
205
*new_packet = realloc(*new_packet,
206
(unsigned int)new_packet_capacity
177
208
if (*new_packet == NULL){
178
209
perror("realloc");
258
fprintf(stderr, "Initializing GnuTLS\n");
217
261
if ((ret = gnutls_global_init ())
218
262
!= GNUTLS_E_SUCCESS) {
219
263
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); */
268
gnutls_global_set_log_level(11);
269
gnutls_global_set_log_function(debuggnutls);
228
272
/* openpgp credentials */
229
273
if ((ret = gnutls_certificate_allocate_credentials (&es->cred))
230
274
!= GNUTLS_E_SUCCESS) {
231
fprintf (stderr, "memory error: %s\n", safer_gnutls_strerror(ret));
275
fprintf (stderr, "memory error: %s\n",
276
safer_gnutls_strerror(ret));
281
fprintf(stderr, "Attempting to use OpenPGP certificate %s"
282
" and keyfile %s as GnuTLS credentials\n", certfile,
235
286
ret = gnutls_certificate_set_openpgp_key_file
236
(es->cred, CERTFILE, KEYFILE, GNUTLS_OPENPGP_FMT_BASE64);
287
(es->cred, certfile, certkey, GNUTLS_OPENPGP_FMT_BASE64);
237
288
if (ret != GNUTLS_E_SUCCESS) {
239
(stderr, "Error[%d] while reading the OpenPGP key pair ('%s', '%s')\n",
240
ret, CERTFILE, KEYFILE);
290
(stderr, "Error[%d] while reading the OpenPGP key pair ('%s',"
292
ret, certfile, certkey);
241
293
fprintf(stdout, "The Error is: %s\n",
242
294
safer_gnutls_strerror(ret));
246
//Gnutls server initialization
298
//GnuTLS server initialization
247
299
if ((ret = gnutls_dh_params_init (&es->dh_params))
248
300
!= GNUTLS_E_SUCCESS) {
249
301
fprintf (stderr, "Error in dh parameter initialization: %s\n",
250
302
safer_gnutls_strerror(ret));
254
306
if ((ret = gnutls_dh_params_generate2 (es->dh_params, DH_BITS))
255
307
!= GNUTLS_E_SUCCESS) {
256
308
fprintf (stderr, "Error in prime generation: %s\n",
257
309
safer_gnutls_strerror(ret));
261
313
gnutls_certificate_set_dh_params (es->cred, es->dh_params);
263
// Gnutls session creation
315
// GnuTLS session creation
264
316
if ((ret = gnutls_init (&es->session, GNUTLS_SERVER))
265
317
!= GNUTLS_E_SUCCESS){
266
fprintf(stderr, "Error in gnutls session initialization: %s\n",
318
fprintf(stderr, "Error in GnuTLS session initialization: %s\n",
267
319
safer_gnutls_strerror(ret));
270
322
if ((ret = gnutls_priority_set_direct (es->session, "NORMAL", &err))
271
323
!= GNUTLS_E_SUCCESS) {
272
324
fprintf(stderr, "Syntax error at: %s\n", err);
273
fprintf(stderr, "Gnutls error: %s\n",
325
fprintf(stderr, "GnuTLS error: %s\n",
274
326
safer_gnutls_strerror(ret));
278
330
if ((ret = gnutls_credentials_set
279
331
(es->session, GNUTLS_CRD_CERTIFICATE, es->cred))
280
332
!= GNUTLS_E_SUCCESS) {
282
334
safer_gnutls_strerror(ret));
286
338
/* ignore client certificate if any. */
287
gnutls_certificate_server_set_request (es->session, GNUTLS_CERT_IGNORE);
339
gnutls_certificate_server_set_request (es->session,
289
342
gnutls_dh_set_prime_bits (es->session, DH_BITS);
294
void empty_log(AvahiLogLevel level, const char *txt){}
347
void empty_log(__attribute__((unused)) AvahiLogLevel level,
348
__attribute__((unused)) const char *txt){}
296
int start_mandos_communcation(char *ip, uint16_t port){
350
int start_mandos_communication(const char *ip, uint16_t port,
351
unsigned int if_index){
298
353
struct sockaddr_in6 to;
299
struct in6_addr ip_addr;
300
354
encrypted_session es;
301
355
char *buffer = NULL;
302
356
char *decrypted_buffer;
303
357
size_t buffer_length = 0;
304
358
size_t buffer_capacity = 0;
305
359
ssize_t decrypted_buffer_size;
362
char interface[IF_NAMESIZE];
365
fprintf(stderr, "Setting up a tcp connection to %s\n", ip);
309
368
tcp_sd = socket(PF_INET6, SOCK_STREAM, 0);
315
ret = setsockopt(tcp_sd, SOL_SOCKET, SO_BINDTODEVICE, "eth0", 5);
317
perror("setsockopt bindtodevice");
374
if(if_indextoname(if_index, interface) == NULL){
376
perror("if_indextoname");
321
memset(&to,0,sizeof(to));
382
fprintf(stderr, "Binding to interface %s\n", interface);
385
memset(&to,0,sizeof(to)); /* Spurious warning */
322
386
to.sin6_family = AF_INET6;
323
ret = inet_pton(AF_INET6, ip, &ip_addr);
387
ret = inet_pton(AF_INET6, ip, &to.sin6_addr);
325
389
perror("inet_pton");
348
gnutls_transport_set_ptr (es.session, (gnutls_transport_ptr_t) tcp_sd);
416
gnutls_transport_set_ptr (es.session,
417
(gnutls_transport_ptr_t) tcp_sd);
420
fprintf(stderr, "Establishing TLS session with %s\n", ip);
350
423
ret = gnutls_handshake (es.session);
352
425
if (ret != GNUTLS_E_SUCCESS){
353
fprintf(stderr, "\n*** Handshake failed ***\n");
427
fprintf(stderr, "\n*** Handshake failed ***\n");
434
//Retrieve OpenPGP packet that contains the wanted password
437
fprintf(stderr, "Retrieving pgp encrypted password from %s\n",
361
442
if (buffer_length + BUFFER_SIZE > buffer_capacity){
362
443
buffer = realloc(buffer, buffer_capacity + BUFFER_SIZE);
390
fprintf(stderr, "Unknown error while reading data from encrypted session with mandos server\n");
471
fprintf(stderr, "Unknown error while reading data from"
472
" encrypted session with mandos server\n");
392
474
gnutls_bye (es.session, GNUTLS_SHUT_RDWR);
396
buffer_length += ret;
478
buffer_length += (size_t) ret;
400
482
if (buffer_length > 0){
401
if ((decrypted_buffer_size = gpg_packet_decrypt(buffer, buffer_length, &decrypted_buffer, CERT_ROOT)) == 0){
483
decrypted_buffer_size = pgp_packet_decrypt(buffer,
487
if (decrypted_buffer_size >= 0){
488
while(written < decrypted_buffer_size){
489
ret = (int)fwrite (decrypted_buffer + written, 1,
490
(size_t)decrypted_buffer_size - written,
492
if(ret == 0 and ferror(stdout)){
494
fprintf(stderr, "Error writing encrypted data: %s\n",
500
written += (size_t)ret;
502
free(decrypted_buffer);
404
fwrite (decrypted_buffer, 1, decrypted_buffer_size, stdout);
405
free(decrypted_buffer);
511
fprintf(stderr, "Closing TLS session\n");
412
515
gnutls_bye (es.session, GNUTLS_SHUT_RDWR);
432
535
const char *host_name,
433
536
const AvahiAddress *address,
435
AvahiStringList *txt,
436
AvahiLookupResultFlags flags,
538
AVAHI_GCC_UNUSED AvahiStringList *txt,
539
AVAHI_GCC_UNUSED AvahiLookupResultFlags flags,
437
540
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);
542
assert(r); /* Spurious warning */
544
/* Called whenever a service has been resolved successfully or
549
case AVAHI_RESOLVER_FAILURE:
550
fprintf(stderr, "(Resolver) Failed to resolve service '%s' of"
551
" type '%s' in domain '%s': %s\n", name, type, domain,
552
avahi_strerror(avahi_server_errno(server)));
555
case AVAHI_RESOLVER_FOUND:
557
char ip[AVAHI_ADDRESS_STR_MAX];
558
avahi_address_snprint(ip, sizeof(ip), address);
560
fprintf(stderr, "Mandos server \"%s\" found on %s (%s) on"
561
" port %d\n", name, host_name, ip, port);
563
int ret = start_mandos_communication(ip, port,
564
(unsigned int) interface);
459
avahi_s_service_resolver_free(r);
570
avahi_s_service_resolver_free(r);
462
573
static void browse_callback(
471
582
void* userdata) {
473
584
AvahiServer *s = userdata;
476
/* Called whenever a new services becomes available on the LAN or is removed from the LAN */
585
assert(b); /* Spurious warning */
587
/* Called whenever a new services becomes available on the LAN or
588
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:
592
case AVAHI_BROWSER_FAILURE:
594
fprintf(stderr, "(Browser) %s\n",
595
avahi_strerror(avahi_server_errno(server)));
596
avahi_simple_poll_quit(simple_poll);
599
case AVAHI_BROWSER_NEW:
600
/* We ignore the returned resolver object. In the callback
601
function we free it. If the server is terminated before
602
the callback function is called the server will free
603
the resolver for us. */
605
if (!(avahi_s_service_resolver_new(s, interface, protocol, name,
607
AVAHI_PROTO_INET6, 0,
608
resolve_callback, s)))
609
fprintf(stderr, "Failed to resolve service '%s': %s\n", name,
610
avahi_strerror(avahi_server_errno(s)));
613
case AVAHI_BROWSER_REMOVE:
616
case AVAHI_BROWSER_ALL_FOR_NOW:
617
case AVAHI_BROWSER_CACHE_EXHAUSTED:
622
/* combinds two strings and returns the malloced new string. som sane checks could/should be added */
623
const char *combinestrings(const char *first, const char *second){
625
tmp = malloc(strlen(first) + strlen(second));
506
636
int main(AVAHI_GCC_UNUSED int argc, AVAHI_GCC_UNUSED char*argv[]) {
507
637
AvahiServerConfig config;
508
638
AvahiSServiceBrowser *sb = NULL;
641
int returncode = EXIT_SUCCESS;
642
const char *interface = "eth0";
645
static struct option long_options[] = {
646
{"debug", no_argument, (int *)&debug, 1},
647
{"interface", required_argument, 0, 'i'},
648
{"certdir", required_argument, 0, 'd'},
649
{"certkey", required_argument, 0, 'c'},
650
{"certfile", required_argument, 0, 'k'},
653
int option_index = 0;
654
ret = getopt_long (argc, argv, "i:", long_options,
512
avahi_set_log_function(empty_log);
681
certfile = combinestrings(certdir, certfile);
682
if (certfile == NULL){
686
certkey = combinestrings(certdir, certkey);
687
if (certkey == NULL){
692
avahi_set_log_function(empty_log);
514
695
/* Initialize the psuedo-RNG */
696
srand((unsigned int) time(NULL));
517
698
/* Allocate main loop object */
518
699
if (!(simple_poll = avahi_simple_poll_new())) {
519
700
fprintf(stderr, "Failed to create simple poll object.\n");
523
705
/* Do not publish any local records */
527
709
config.publish_workstation = 0;
528
710
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
712
/* Allocate a new server */
536
server = avahi_server_new(avahi_simple_poll_get(simple_poll), &config, NULL, NULL, &error);
713
server = avahi_server_new(avahi_simple_poll_get(simple_poll),
714
&config, NULL, NULL, &error);
538
716
/* Free the configuration data */
539
717
avahi_server_config_free(&config);
541
/* Check wether creating the server object succeeded */
719
/* Check if creating the server object succeeded */
543
fprintf(stderr, "Failed to create server: %s\n", avahi_strerror(error));
721
fprintf(stderr, "Failed to create server: %s\n",
722
avahi_strerror(error));
723
returncode = EXIT_FAILURE;
547
727
/* 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)));
728
sb = avahi_s_service_browser_new(server,
730
if_nametoindex(interface),
732
"_mandos._tcp", NULL, 0,
733
browse_callback, server);
735
fprintf(stderr, "Failed to create service browser: %s\n",
736
avahi_strerror(avahi_server_errno(server)));
737
returncode = EXIT_FAILURE;
553
741
/* Run the main loop */
744
fprintf(stderr, "Starting avahi loop search\n");
554
747
avahi_simple_poll_loop(simple_poll);
752
fprintf(stderr, "%s exiting\n", argv[0]);
560
755
/* Cleanup things */