32
32
/* Needed by GPGME, specifically gpgme_data_seek() */
33
#ifndef _LARGEFILE_SOURCE
33
34
#define _LARGEFILE_SOURCE
36
#ifndef _FILE_OFFSET_BITS
34
37
#define _FILE_OFFSET_BITS 64
36
40
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), asprintf() */
38
42
#include <stdio.h> /* fprintf(), stderr, fwrite(),
39
stdout, ferror(), sscanf(),
43
stdout, ferror(), remove() */
41
44
#include <stdint.h> /* uint16_t, uint32_t */
42
45
#include <stddef.h> /* NULL, size_t, ssize_t */
43
46
#include <stdlib.h> /* free(), EXIT_SUCCESS, EXIT_FAILURE,
45
48
#include <stdbool.h> /* bool, false, true */
46
49
#include <string.h> /* memset(), strcmp(), strlen(),
47
50
strerror(), asprintf(), strcpy() */
56
59
#include <fcntl.h> /* open() */
57
60
#include <dirent.h> /* opendir(), struct dirent, readdir()
59
#include <inttypes.h> /* PRIu16, intmax_t, SCNdMAX */
62
#include <inttypes.h> /* PRIu16, PRIdMAX, intmax_t,
60
64
#include <assert.h> /* assert() */
61
65
#include <errno.h> /* perror(), errno */
62
66
#include <time.h> /* nanosleep(), time() */
75
79
argp_state, struct argp,
76
80
argp_parse(), ARGP_KEY_ARG,
77
81
ARGP_KEY_END, ARGP_ERR_UNKNOWN */
82
#include <signal.h> /* sigemptyset(), sigaddset(),
83
sigaction(), SIGTERM, sigaction,
79
87
#include <sys/klog.h> /* klogctl() */
88
#endif /* __linux__ */
83
91
/* All Avahi types, constants and functions
130
138
} mandos_context;
140
/* global context so signal handler can reach it*/
141
mandos_context mc = { .simple_poll = NULL, .server = NULL,
142
.dh_bits = 1024, .priority = "SECURE256"
143
":!CTYPE-X.509:+CTYPE-OPENPGP" };
133
* Make room in "buffer" for at least BUFFER_SIZE additional bytes.
134
* "buffer_capacity" is how much is currently allocated,
146
* Make additional room in "buffer" for at least BUFFER_SIZE more
147
* bytes. "buffer_capacity" is how much is currently allocated,
135
148
* "buffer_length" is how much is already used.
137
size_t adjustbuffer(char **buffer, size_t buffer_length,
150
size_t incbuffer(char **buffer, size_t buffer_length,
138
151
size_t buffer_capacity){
139
152
if(buffer_length + BUFFER_SIZE > buffer_capacity){
140
153
*buffer = realloc(*buffer, buffer_capacity + BUFFER_SIZE);
150
163
* Initialize GPGME.
152
static bool init_gpgme(mandos_context *mc, const char *seckey,
165
static bool init_gpgme(const char *seckey,
153
166
const char *pubkey, const char *tempdir){
155
168
gpgme_error_t rc;
179
rc = gpgme_op_import(mc->ctx, pgp_data);
192
rc = gpgme_op_import(mc.ctx, pgp_data);
180
193
if(rc != GPG_ERR_NO_ERROR){
181
194
fprintf(stderr, "bad gpgme_op_import: %s: %s\n",
182
195
gpgme_strsource(rc), gpgme_strerror(rc));
227
240
/* Create new GPGME "context" */
228
rc = gpgme_new(&(mc->ctx));
241
rc = gpgme_new(&(mc.ctx));
229
242
if(rc != GPG_ERR_NO_ERROR){
230
243
fprintf(stderr, "bad gpgme_new: %s: %s\n",
231
244
gpgme_strsource(rc), gpgme_strerror(rc));
243
256
* Decrypt OpenPGP data.
244
257
* Returns -1 on error
246
static ssize_t pgp_packet_decrypt(const mandos_context *mc,
247
const char *cryptotext,
259
static ssize_t pgp_packet_decrypt(const char *cryptotext,
248
260
size_t crypto_size,
249
261
char **plaintext){
250
262
gpgme_data_t dh_crypto, dh_plain;
278
290
/* Decrypt data from the cryptotext data buffer to the plaintext
280
rc = gpgme_op_decrypt(mc->ctx, dh_crypto, dh_plain);
292
rc = gpgme_op_decrypt(mc.ctx, dh_crypto, dh_plain);
281
293
if(rc != GPG_ERR_NO_ERROR){
282
294
fprintf(stderr, "bad gpgme_op_decrypt: %s: %s\n",
283
295
gpgme_strsource(rc), gpgme_strerror(rc));
284
296
plaintext_length = -1;
286
298
gpgme_decrypt_result_t result;
287
result = gpgme_op_decrypt_result(mc->ctx);
299
result = gpgme_op_decrypt_result(mc.ctx);
288
300
if(result == NULL){
289
301
fprintf(stderr, "gpgme_op_decrypt_result failed\n");
298
310
gpgme_recipient_t recipient;
299
311
recipient = result->recipients;
301
while(recipient != NULL){
302
fprintf(stderr, "Public key algorithm: %s\n",
303
gpgme_pubkey_algo_name(recipient->pubkey_algo));
304
fprintf(stderr, "Key ID: %s\n", recipient->keyid);
305
fprintf(stderr, "Secret key available: %s\n",
306
recipient->status == GPG_ERR_NO_SECKEY
308
recipient = recipient->next;
312
while(recipient != NULL){
313
fprintf(stderr, "Public key algorithm: %s\n",
314
gpgme_pubkey_algo_name(recipient->pubkey_algo));
315
fprintf(stderr, "Key ID: %s\n", recipient->keyid);
316
fprintf(stderr, "Secret key available: %s\n",
317
recipient->status == GPG_ERR_NO_SECKEY
319
recipient = recipient->next;
327
337
*plaintext = NULL;
329
plaintext_capacity = adjustbuffer(plaintext,
339
plaintext_capacity = incbuffer(plaintext,
330
340
(size_t)plaintext_length,
331
341
plaintext_capacity);
332
342
if(plaintext_capacity == 0){
333
perror("adjustbuffer");
334
344
plaintext_length = -1;
335
345
goto decrypt_end;
382
392
fprintf(stderr, "GnuTLS: %s", string);
385
static int init_gnutls_global(mandos_context *mc,
386
const char *pubkeyfilename,
395
static int init_gnutls_global(const char *pubkeyfilename,
387
396
const char *seckeyfilename){
409
418
/* OpenPGP credentials */
410
gnutls_certificate_allocate_credentials(&mc->cred);
419
gnutls_certificate_allocate_credentials(&mc.cred);
411
420
if(ret != GNUTLS_E_SUCCESS){
412
421
fprintf(stderr, "GnuTLS memory error: %s\n", /* Spurious warning
427
436
ret = gnutls_certificate_set_openpgp_key_file
428
(mc->cred, pubkeyfilename, seckeyfilename,
437
(mc.cred, pubkeyfilename, seckeyfilename,
429
438
GNUTLS_OPENPGP_FMT_BASE64);
430
439
if(ret != GNUTLS_E_SUCCESS){
439
448
/* GnuTLS server initialization */
440
ret = gnutls_dh_params_init(&mc->dh_params);
449
ret = gnutls_dh_params_init(&mc.dh_params);
441
450
if(ret != GNUTLS_E_SUCCESS){
442
451
fprintf(stderr, "Error in GnuTLS DH parameter initialization:"
443
452
" %s\n", safer_gnutls_strerror(ret));
446
ret = gnutls_dh_params_generate2(mc->dh_params, mc->dh_bits);
455
ret = gnutls_dh_params_generate2(mc.dh_params, mc.dh_bits);
447
456
if(ret != GNUTLS_E_SUCCESS){
448
457
fprintf(stderr, "Error in GnuTLS prime generation: %s\n",
449
458
safer_gnutls_strerror(ret));
453
gnutls_certificate_set_dh_params(mc->cred, mc->dh_params);
462
gnutls_certificate_set_dh_params(mc.cred, mc.dh_params);
459
gnutls_certificate_free_credentials(mc->cred);
468
gnutls_certificate_free_credentials(mc.cred);
460
469
gnutls_global_deinit();
461
gnutls_dh_params_deinit(mc->dh_params);
470
gnutls_dh_params_deinit(mc.dh_params);
465
static int init_gnutls_session(mandos_context *mc,
466
gnutls_session_t *session){
474
static int init_gnutls_session(gnutls_session_t *session){
468
476
/* GnuTLS session creation */
469
477
ret = gnutls_init(session, GNUTLS_SERVER);
477
ret = gnutls_priority_set_direct(*session, mc->priority, &err);
485
ret = gnutls_priority_set_direct(*session, mc.priority, &err);
478
486
if(ret != GNUTLS_E_SUCCESS){
479
487
fprintf(stderr, "Syntax error at: %s\n", err);
480
488
fprintf(stderr, "GnuTLS error: %s\n",
487
495
ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,
489
497
if(ret != GNUTLS_E_SUCCESS){
490
498
fprintf(stderr, "Error setting GnuTLS credentials: %s\n",
491
499
safer_gnutls_strerror(ret));
497
505
gnutls_certificate_server_set_request(*session,
498
506
GNUTLS_CERT_IGNORE);
500
gnutls_dh_set_prime_bits(*session, mc->dh_bits);
508
gnutls_dh_set_prime_bits(*session, mc.dh_bits);
509
517
/* Called when a Mandos server is found */
510
518
static int start_mandos_communication(const char *ip, uint16_t port,
511
519
AvahiIfIndex if_index,
512
mandos_context *mc, int af){
557
565
memset(&to, 0, sizeof(to));
558
566
if(af == AF_INET6){
559
to.in6.sin6_family = (uint16_t)af;
567
to.in6.sin6_family = (sa_family_t)af;
560
568
ret = inet_pton(af, ip, &to.in6.sin6_addr);
561
569
} else { /* IPv4 */
562
570
to.in.sin_family = (sa_family_t)af;
688
buffer_capacity = adjustbuffer(&buffer, buffer_length,
696
buffer_capacity = incbuffer(&buffer, buffer_length,
689
697
buffer_capacity);
690
698
if(buffer_capacity == 0){
691
perror("adjustbuffer");
733
741
gnutls_bye(session, GNUTLS_SHUT_RDWR);
735
743
if(buffer_length > 0){
736
decrypted_buffer_size = pgp_packet_decrypt(mc, buffer,
744
decrypted_buffer_size = pgp_packet_decrypt(buffer,
738
746
&decrypted_buffer);
739
747
if(decrypted_buffer_size >= 0){
785
793
AVAHI_GCC_UNUSED AvahiStringList *txt,
786
794
AVAHI_GCC_UNUSED AvahiLookupResultFlags
789
mandos_context *mc = userdata;
796
AVAHI_GCC_UNUSED void* userdata){
792
799
/* Called whenever a service has been resolved successfully or
797
804
case AVAHI_RESOLVER_FAILURE:
798
805
fprintf(stderr, "(Avahi Resolver) Failed to resolve service '%s'"
799
806
" of type '%s' in domain '%s': %s\n", name, type, domain,
800
avahi_strerror(avahi_server_errno(mc->server)));
807
avahi_strerror(avahi_server_errno(mc.server)));
803
810
case AVAHI_RESOLVER_FOUND:
809
816
PRIdMAX ") on port %" PRIu16 "\n", name, host_name,
810
817
ip, (intmax_t)interface, port);
812
int ret = start_mandos_communication(ip, port, interface, mc,
819
int ret = start_mandos_communication(ip, port, interface,
813
820
avahi_proto_to_af(proto));
815
avahi_simple_poll_quit(mc->simple_poll);
822
avahi_simple_poll_quit(mc.simple_poll);
840
846
case AVAHI_BROWSER_FAILURE:
842
848
fprintf(stderr, "(Avahi browser) %s\n",
843
avahi_strerror(avahi_server_errno(mc->server)));
844
avahi_simple_poll_quit(mc->simple_poll);
849
avahi_strerror(avahi_server_errno(mc.server)));
850
avahi_simple_poll_quit(mc.simple_poll);
847
853
case AVAHI_BROWSER_NEW:
850
856
the callback function is called the Avahi server will free the
851
857
resolver for us. */
853
if(!(avahi_s_service_resolver_new(mc->server, interface,
854
protocol, name, type, domain,
855
AVAHI_PROTO_INET6, 0,
856
resolve_callback, mc)))
859
if(avahi_s_service_resolver_new(mc.server, interface, protocol,
860
name, type, domain, protocol, 0,
861
resolve_callback, NULL) == NULL)
857
862
fprintf(stderr, "Avahi: Failed to resolve service '%s': %s\n",
858
name, avahi_strerror(avahi_server_errno(mc->server)));
863
name, avahi_strerror(avahi_server_errno(mc.server)));
861
866
case AVAHI_BROWSER_REMOVE:
878
sig_atomic_t quit_now = 0;
880
/* stop main loop after sigterm has been called */
881
static void handle_sigterm(__attribute__((unused)) int sig){
886
int old_errno = errno;
887
if(mc.simple_poll != NULL){
888
avahi_simple_poll_quit(mc.simple_poll);
873
893
int main(int argc, char *argv[]){
874
894
AvahiSServiceBrowser *sb = NULL;
879
899
int exitcode = EXIT_SUCCESS;
880
900
const char *interface = "eth0";
881
901
struct ifreq network;
903
bool interface_taken_up = false;
885
906
char *connect_to = NULL;
889
910
const char *seckey = PATHDIR "/" SECKEY;
890
911
const char *pubkey = PATHDIR "/" PUBKEY;
892
mandos_context mc = { .simple_poll = NULL, .server = NULL,
893
.dh_bits = 1024, .priority = "SECURE256"
894
":!CTYPE-X.509:+CTYPE-OPENPGP" };
895
913
bool gnutls_initialized = false;
896
914
bool gpgme_initialized = false;
917
struct sigaction old_sigterm_action;
918
struct sigaction sigterm_action = { .sa_handler = handle_sigterm };
900
921
struct argp_option options[] = {
954
975
case 129: /* --dh-bits */
955
ret = sscanf(arg, "%" SCNdMAX "%n", &tmpmax, &numchars);
956
if(ret < 1 or tmpmax != (typeof(mc.dh_bits))tmpmax
957
or arg[numchars] != '\0'){
977
tmpmax = strtoimax(arg, &tmp, 10);
978
if(errno != 0 or tmp == arg or *tmp != '\0'
979
or tmpmax != (typeof(mc.dh_bits))tmpmax){
958
980
fprintf(stderr, "Bad number of DH bits\n");
959
981
exit(EXIT_FAILURE);
964
986
mc.priority = arg;
966
988
case 131: /* --delay */
967
ret = sscanf(arg, "%lf%n", &delay, &numchars);
968
if(ret < 1 or arg[numchars] != '\0'){
990
delay = strtof(arg, &tmp);
991
if(errno != 0 or tmp == arg or *tmp != '\0'){
969
992
fprintf(stderr, "Bad delay\n");
970
993
exit(EXIT_FAILURE);
1019
avahi_set_log_function(empty_log);
1022
/* Initialize Avahi early so avahi_simple_poll_quit() can be called
1023
from the signal handler */
1024
/* Initialize the pseudo-RNG for Avahi */
1025
srand((unsigned int) time(NULL));
1026
mc.simple_poll = avahi_simple_poll_new();
1027
if(mc.simple_poll == NULL){
1028
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1029
exitcode = EXIT_FAILURE;
1033
sigemptyset(&sigterm_action.sa_mask);
1034
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1036
perror("sigaddset");
1037
exitcode = EXIT_FAILURE;
1040
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1042
perror("sigaddset");
1043
exitcode = EXIT_FAILURE;
1046
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1048
perror("sigaddset");
1049
exitcode = EXIT_FAILURE;
1052
ret = sigaction(SIGTERM, &sigterm_action, &old_sigterm_action);
1054
perror("sigaction");
1055
exitcode = EXIT_FAILURE;
995
1059
/* If the interface is down, bring it up */
996
1060
if(interface[0] != '\0'){
997
1061
#ifdef __linux__
1094
1161
perror("setuid");
1097
ret = init_gnutls_global(&mc, pubkey, seckey);
1164
ret = init_gnutls_global(pubkey, seckey);
1099
1166
fprintf(stderr, "init_gnutls_global failed\n");
1100
1167
exitcode = EXIT_FAILURE;
1110
1177
tempdir_created = true;
1112
if(not init_gpgme(&mc, pubkey, seckey, tempdir)){
1179
if(not init_gpgme(pubkey, seckey, tempdir)){
1113
1180
fprintf(stderr, "init_gpgme failed\n");
1114
1181
exitcode = EXIT_FAILURE;
1139
ret = sscanf(address+1, "%" SCNdMAX "%n", &tmpmax, &numchars);
1140
if(ret < 1 or tmpmax != (uint16_t)tmpmax
1141
or address[numchars+1] != '\0'){
1207
tmpmax = strtoimax(address+1, &tmp, 10);
1208
if(errno != 0 or tmp == address+1 or *tmp != '\0'
1209
or tmpmax != (uint16_t)tmpmax){
1142
1210
fprintf(stderr, "Bad port number\n");
1143
1211
exitcode = EXIT_FAILURE;
1156
ret = start_mandos_communication(address, port, if_index, &mc,
1224
ret = start_mandos_communication(address, port, if_index, af);
1159
1226
exitcode = EXIT_FAILURE;
1167
avahi_set_log_function(empty_log);
1170
/* Initialize the pseudo-RNG for Avahi */
1171
srand((unsigned int) time(NULL));
1173
/* Allocate main Avahi loop object */
1174
mc.simple_poll = avahi_simple_poll_new();
1175
if(mc.simple_poll == NULL){
1176
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1177
exitcode = EXIT_FAILURE;
1182
1234
AvahiServerConfig config;
1183
1235
/* Do not publish any local Zeroconf records */
1207
1259
/* Create the Avahi service browser */
1208
1260
sb = avahi_s_service_browser_new(mc.server, if_index,
1209
AVAHI_PROTO_INET6, "_mandos._tcp",
1210
NULL, 0, browse_callback, &mc);
1261
AVAHI_PROTO_UNSPEC, "_mandos._tcp",
1262
NULL, 0, browse_callback, NULL);
1211
1263
if(sb == NULL){
1212
1264
fprintf(stderr, "Failed to create service browser: %s\n",
1213
1265
avahi_strerror(avahi_server_errno(mc.server)));
1249
1301
gpgme_release(mc.ctx);
1304
/* Take down the network interface */
1305
if(interface_taken_up){
1306
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1308
perror("ioctl SIOCGIFFLAGS");
1309
} else if(network.ifr_flags & IFF_UP) {
1310
network.ifr_flags &= ~IFF_UP; /* clear flag */
1311
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1313
perror("ioctl SIOCSIFFLAGS");
1316
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1252
1322
/* Removes the temp directory used by GPGME */
1253
1323
if(tempdir_created){