32
32
/* Needed by GPGME, specifically gpgme_data_seek() */
33
#ifndef _LARGEFILE_SOURCE
34
33
#define _LARGEFILE_SOURCE
36
#ifndef _FILE_OFFSET_BITS
37
34
#define _FILE_OFFSET_BITS 64
40
36
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), asprintf() */
42
38
#include <stdio.h> /* fprintf(), stderr, fwrite(),
43
stdout, ferror(), remove() */
39
stdout, ferror(), sscanf(),
44
41
#include <stdint.h> /* uint16_t, uint32_t */
45
42
#include <stddef.h> /* NULL, size_t, ssize_t */
46
43
#include <stdlib.h> /* free(), EXIT_SUCCESS, EXIT_FAILURE,
48
45
#include <stdbool.h> /* bool, false, true */
49
46
#include <string.h> /* memset(), strcmp(), strlen(),
50
47
strerror(), asprintf(), strcpy() */
59
56
#include <fcntl.h> /* open() */
60
57
#include <dirent.h> /* opendir(), struct dirent, readdir()
62
#include <inttypes.h> /* PRIu16, PRIdMAX, intmax_t,
59
#include <inttypes.h> /* PRIu16, intmax_t, SCNdMAX */
64
60
#include <assert.h> /* assert() */
65
61
#include <errno.h> /* perror(), errno */
66
62
#include <time.h> /* nanosleep(), time() */
79
75
argp_state, struct argp,
80
76
argp_parse(), ARGP_KEY_ARG,
81
77
ARGP_KEY_END, ARGP_ERR_UNKNOWN */
82
#include <signal.h> /* sigemptyset(), sigaddset(),
83
sigaction(), SIGTERM, sig_atomic_t,
87
79
#include <sys/klog.h> /* klogctl() */
88
#endif /* __linux__ */
91
83
/* All Avahi types, constants and functions
138
130
} 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" };
146
* Make additional room in "buffer" for at least BUFFER_SIZE more
147
* bytes. "buffer_capacity" is how much is currently allocated,
133
* Make room in "buffer" for at least BUFFER_SIZE additional bytes.
134
* "buffer_capacity" is how much is currently allocated,
148
135
* "buffer_length" is how much is already used.
150
size_t incbuffer(char **buffer, size_t buffer_length,
137
size_t adjustbuffer(char **buffer, size_t buffer_length,
151
138
size_t buffer_capacity){
152
139
if(buffer_length + BUFFER_SIZE > buffer_capacity){
153
140
*buffer = realloc(*buffer, buffer_capacity + BUFFER_SIZE);
163
150
* Initialize GPGME.
165
static bool init_gpgme(const char *seckey,
152
static bool init_gpgme(mandos_context *mc, const char *seckey,
166
153
const char *pubkey, const char *tempdir){
168
155
gpgme_error_t rc;
192
rc = gpgme_op_import(mc.ctx, pgp_data);
179
rc = gpgme_op_import(mc->ctx, pgp_data);
193
180
if(rc != GPG_ERR_NO_ERROR){
194
181
fprintf(stderr, "bad gpgme_op_import: %s: %s\n",
195
182
gpgme_strsource(rc), gpgme_strerror(rc));
240
227
/* Create new GPGME "context" */
241
rc = gpgme_new(&(mc.ctx));
228
rc = gpgme_new(&(mc->ctx));
242
229
if(rc != GPG_ERR_NO_ERROR){
243
230
fprintf(stderr, "bad gpgme_new: %s: %s\n",
244
231
gpgme_strsource(rc), gpgme_strerror(rc));
290
278
/* Decrypt data from the cryptotext data buffer to the plaintext
292
rc = gpgme_op_decrypt(mc.ctx, dh_crypto, dh_plain);
280
rc = gpgme_op_decrypt(mc->ctx, dh_crypto, dh_plain);
293
281
if(rc != GPG_ERR_NO_ERROR){
294
282
fprintf(stderr, "bad gpgme_op_decrypt: %s: %s\n",
295
283
gpgme_strsource(rc), gpgme_strerror(rc));
296
284
plaintext_length = -1;
298
286
gpgme_decrypt_result_t result;
299
result = gpgme_op_decrypt_result(mc.ctx);
287
result = gpgme_op_decrypt_result(mc->ctx);
300
288
if(result == NULL){
301
289
fprintf(stderr, "gpgme_op_decrypt_result failed\n");
310
298
gpgme_recipient_t recipient;
311
299
recipient = result->recipients;
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;
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;
337
327
*plaintext = NULL;
339
plaintext_capacity = incbuffer(plaintext,
329
plaintext_capacity = adjustbuffer(plaintext,
340
330
(size_t)plaintext_length,
341
331
plaintext_capacity);
342
332
if(plaintext_capacity == 0){
333
perror("adjustbuffer");
344
334
plaintext_length = -1;
345
335
goto decrypt_end;
392
382
fprintf(stderr, "GnuTLS: %s", string);
395
static int init_gnutls_global(const char *pubkeyfilename,
385
static int init_gnutls_global(mandos_context *mc,
386
const char *pubkeyfilename,
396
387
const char *seckeyfilename){
418
409
/* OpenPGP credentials */
419
gnutls_certificate_allocate_credentials(&mc.cred);
410
gnutls_certificate_allocate_credentials(&mc->cred);
420
411
if(ret != GNUTLS_E_SUCCESS){
421
412
fprintf(stderr, "GnuTLS memory error: %s\n", /* Spurious warning
436
427
ret = gnutls_certificate_set_openpgp_key_file
437
(mc.cred, pubkeyfilename, seckeyfilename,
428
(mc->cred, pubkeyfilename, seckeyfilename,
438
429
GNUTLS_OPENPGP_FMT_BASE64);
439
430
if(ret != GNUTLS_E_SUCCESS){
448
439
/* GnuTLS server initialization */
449
ret = gnutls_dh_params_init(&mc.dh_params);
440
ret = gnutls_dh_params_init(&mc->dh_params);
450
441
if(ret != GNUTLS_E_SUCCESS){
451
442
fprintf(stderr, "Error in GnuTLS DH parameter initialization:"
452
443
" %s\n", safer_gnutls_strerror(ret));
455
ret = gnutls_dh_params_generate2(mc.dh_params, mc.dh_bits);
446
ret = gnutls_dh_params_generate2(mc->dh_params, mc->dh_bits);
456
447
if(ret != GNUTLS_E_SUCCESS){
457
448
fprintf(stderr, "Error in GnuTLS prime generation: %s\n",
458
449
safer_gnutls_strerror(ret));
462
gnutls_certificate_set_dh_params(mc.cred, mc.dh_params);
453
gnutls_certificate_set_dh_params(mc->cred, mc->dh_params);
468
gnutls_certificate_free_credentials(mc.cred);
459
gnutls_certificate_free_credentials(mc->cred);
469
460
gnutls_global_deinit();
470
gnutls_dh_params_deinit(mc.dh_params);
461
gnutls_dh_params_deinit(mc->dh_params);
474
static int init_gnutls_session(gnutls_session_t *session){
465
static int init_gnutls_session(mandos_context *mc,
466
gnutls_session_t *session){
476
468
/* GnuTLS session creation */
477
469
ret = gnutls_init(session, GNUTLS_SERVER);
485
ret = gnutls_priority_set_direct(*session, mc.priority, &err);
477
ret = gnutls_priority_set_direct(*session, mc->priority, &err);
486
478
if(ret != GNUTLS_E_SUCCESS){
487
479
fprintf(stderr, "Syntax error at: %s\n", err);
488
480
fprintf(stderr, "GnuTLS error: %s\n",
495
487
ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,
497
489
if(ret != GNUTLS_E_SUCCESS){
498
490
fprintf(stderr, "Error setting GnuTLS credentials: %s\n",
499
491
safer_gnutls_strerror(ret));
514
506
static void empty_log(__attribute__((unused)) AvahiLogLevel level,
515
507
__attribute__((unused)) const char *txt){}
517
sig_atomic_t quit_now = 0;
518
int signal_received = 0;
520
509
/* Called when a Mandos server is found */
521
510
static int start_mandos_communication(const char *ip, uint16_t port,
522
511
AvahiIfIndex if_index,
524
int ret, tcp_sd = -1;
512
mandos_context *mc, int af){
527
516
struct sockaddr_in in;
566
551
tcp_sd = socket(pf, SOCK_STREAM, 0);
568
553
perror("socket");
577
557
memset(&to, 0, sizeof(to));
578
558
if(af == AF_INET6){
579
to.in6.sin6_family = (sa_family_t)af;
559
to.in6.sin6_family = (uint16_t)af;
580
560
ret = inet_pton(af, ip, &to.in6.sin6_addr);
581
561
} else { /* IPv4 */
582
562
to.in.sin_family = (sa_family_t)af;
603
581
if(if_index == AVAHI_IF_UNSPEC){
604
582
fprintf(stderr, "An IPv6 link-local address is incomplete"
605
583
" without a network interface\n");
609
586
/* Set the network interface number as scope */
610
587
to.in6.sin6_scope_id = (uint32_t)if_index;
702
662
fprintf(stderr, "Establishing TLS session with %s\n", ip);
709
665
gnutls_transport_set_ptr(session, (gnutls_transport_ptr_t) tcp_sd);
716
668
ret = gnutls_handshake(session);
720
669
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
722
671
if(ret != GNUTLS_E_SUCCESS){
744
buffer_capacity = incbuffer(&buffer, buffer_length,
688
buffer_capacity = adjustbuffer(&buffer, buffer_length,
745
689
buffer_capacity);
746
690
if(buffer_capacity == 0){
691
perror("adjustbuffer");
756
696
sret = gnutls_record_recv(session, buffer+buffer_length,
766
706
case GNUTLS_E_REHANDSHAKE:
768
708
ret = gnutls_handshake(session);
773
709
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
775
711
fprintf(stderr, "*** GnuTLS Re-handshake failed ***\n");
794
730
fprintf(stderr, "Closing TLS session\n");
801
733
gnutls_bye(session, GNUTLS_SHUT_RDWR);
807
735
if(buffer_length > 0){
808
decrypted_buffer_size = pgp_packet_decrypt(buffer,
736
decrypted_buffer_size = pgp_packet_decrypt(mc, buffer,
810
738
&decrypted_buffer);
811
739
if(decrypted_buffer_size >= 0){
813
741
while(written < (size_t) decrypted_buffer_size){
818
742
ret = (int)fwrite(decrypted_buffer + written, 1,
819
743
(size_t)decrypted_buffer_size - written,
866
785
AVAHI_GCC_UNUSED AvahiStringList *txt,
867
786
AVAHI_GCC_UNUSED AvahiLookupResultFlags
869
AVAHI_GCC_UNUSED void* userdata){
789
mandos_context *mc = userdata;
872
792
/* Called whenever a service has been resolved successfully or
881
797
case AVAHI_RESOLVER_FAILURE:
882
798
fprintf(stderr, "(Avahi Resolver) Failed to resolve service '%s'"
883
799
" of type '%s' in domain '%s': %s\n", name, type, domain,
884
avahi_strerror(avahi_server_errno(mc.server)));
800
avahi_strerror(avahi_server_errno(mc->server)));
887
803
case AVAHI_RESOLVER_FOUND:
893
809
PRIdMAX ") on port %" PRIu16 "\n", name, host_name,
894
810
ip, (intmax_t)interface, port);
896
int ret = start_mandos_communication(ip, port, interface,
812
int ret = start_mandos_communication(ip, port, interface, mc,
897
813
avahi_proto_to_af(proto));
899
avahi_simple_poll_quit(mc.simple_poll);
815
avahi_simple_poll_quit(mc->simple_poll);
912
828
const char *domain,
913
829
AVAHI_GCC_UNUSED AvahiLookupResultFlags
915
AVAHI_GCC_UNUSED void* userdata){
832
mandos_context *mc = userdata;
918
835
/* Called whenever a new services becomes available on the LAN or
919
836
is removed from the LAN */
927
840
case AVAHI_BROWSER_FAILURE:
929
842
fprintf(stderr, "(Avahi browser) %s\n",
930
avahi_strerror(avahi_server_errno(mc.server)));
931
avahi_simple_poll_quit(mc.simple_poll);
843
avahi_strerror(avahi_server_errno(mc->server)));
844
avahi_simple_poll_quit(mc->simple_poll);
934
847
case AVAHI_BROWSER_NEW:
937
850
the callback function is called the Avahi server will free the
938
851
resolver for us. */
940
if(avahi_s_service_resolver_new(mc.server, interface, protocol,
941
name, type, domain, protocol, 0,
942
resolve_callback, NULL) == NULL)
853
if(!(avahi_s_service_resolver_new(mc->server, interface,
854
protocol, name, type, domain,
855
AVAHI_PROTO_INET6, 0,
856
resolve_callback, mc)))
943
857
fprintf(stderr, "Avahi: Failed to resolve service '%s': %s\n",
944
name, avahi_strerror(avahi_server_errno(mc.server)));
858
name, avahi_strerror(avahi_server_errno(mc->server)));
947
861
case AVAHI_BROWSER_REMOVE:
959
/* stop main loop after sigterm has been called */
960
static void handle_sigterm(int sig){
965
signal_received = sig;
966
int old_errno = errno;
967
if(mc.simple_poll != NULL){
968
avahi_simple_poll_quit(mc.simple_poll);
973
873
int main(int argc, char *argv[]){
974
874
AvahiSServiceBrowser *sb = NULL;
979
879
int exitcode = EXIT_SUCCESS;
980
880
const char *interface = "eth0";
981
881
struct ifreq network;
983
bool take_down_interface = false;
986
885
char *connect_to = NULL;
990
889
const char *seckey = PATHDIR "/" SECKEY;
991
890
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" };
993
895
bool gnutls_initialized = false;
994
896
bool gpgme_initialized = false;
997
struct sigaction old_sigterm_action;
998
struct sigaction sigterm_action = { .sa_handler = handle_sigterm };
1001
900
struct argp_option options[] = {
1055
954
case 129: /* --dh-bits */
1057
tmpmax = strtoimax(arg, &tmp, 10);
1058
if(errno != 0 or tmp == arg or *tmp != '\0'
1059
or tmpmax != (typeof(mc.dh_bits))tmpmax){
955
ret = sscanf(arg, "%" SCNdMAX "%n", &tmpmax, &numchars);
956
if(ret < 1 or tmpmax != (typeof(mc.dh_bits))tmpmax
957
or arg[numchars] != '\0'){
1060
958
fprintf(stderr, "Bad number of DH bits\n");
1061
959
exit(EXIT_FAILURE);
1066
964
mc.priority = arg;
1068
966
case 131: /* --delay */
1070
delay = strtof(arg, &tmp);
1071
if(errno != 0 or tmp == arg or *tmp != '\0'){
967
ret = sscanf(arg, "%lf%n", &delay, &numchars);
968
if(ret < 1 or arg[numchars] != '\0'){
1072
969
fprintf(stderr, "Bad delay\n");
1073
970
exit(EXIT_FAILURE);
1099
avahi_set_log_function(empty_log);
1102
/* Initialize Avahi early so avahi_simple_poll_quit() can be called
1103
from the signal handler */
1104
/* Initialize the pseudo-RNG for Avahi */
1105
srand((unsigned int) time(NULL));
1106
mc.simple_poll = avahi_simple_poll_new();
1107
if(mc.simple_poll == NULL){
1108
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1109
exitcode = EXIT_FAILURE;
1113
sigemptyset(&sigterm_action.sa_mask);
1114
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1116
perror("sigaddset");
1117
exitcode = EXIT_FAILURE;
1120
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1122
perror("sigaddset");
1123
exitcode = EXIT_FAILURE;
1126
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1128
perror("sigaddset");
1129
exitcode = EXIT_FAILURE;
1132
/* Need to check if the handler is SIG_IGN before handling:
1133
| [[info:libc:Initial Signal Actions]] |
1134
| [[info:libc:Basic Signal Handling]] |
1136
ret = sigaction(SIGINT, NULL, &old_sigterm_action);
1138
perror("sigaction");
1139
return EXIT_FAILURE;
1141
if(old_sigterm_action.sa_handler != SIG_IGN){
1142
ret = sigaction(SIGINT, &sigterm_action, NULL);
1144
perror("sigaction");
1145
exitcode = EXIT_FAILURE;
1149
ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
1151
perror("sigaction");
1152
return EXIT_FAILURE;
1154
if(old_sigterm_action.sa_handler != SIG_IGN){
1155
ret = sigaction(SIGHUP, &sigterm_action, NULL);
1157
perror("sigaction");
1158
exitcode = EXIT_FAILURE;
1162
ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
1164
perror("sigaction");
1165
return EXIT_FAILURE;
1167
if(old_sigterm_action.sa_handler != SIG_IGN){
1168
ret = sigaction(SIGTERM, &sigterm_action, NULL);
1170
perror("sigaction");
1171
exitcode = EXIT_FAILURE;
1176
995
/* If the interface is down, bring it up */
1177
996
if(interface[0] != '\0'){
1178
if_index = (AvahiIfIndex) if_nametoindex(interface);
1180
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1181
exitcode = EXIT_FAILURE;
1189
997
#ifdef __linux__
1190
998
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1191
999
messages to mess up the prompt */
1222
1030
perror("klogctl");
1225
#endif /* __linux__ */
1226
1034
exitcode = EXIT_FAILURE;
1229
1037
if((network.ifr_flags & IFF_UP) == 0){
1230
1038
network.ifr_flags |= IFF_UP;
1231
take_down_interface = true;
1232
1039
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1234
take_down_interface = false;
1235
1041
perror("ioctl SIOCSIFFLAGS");
1236
1042
exitcode = EXIT_FAILURE;
1237
1043
#ifdef __linux__
1295
1094
perror("setuid");
1302
ret = init_gnutls_global(pubkey, seckey);
1097
ret = init_gnutls_global(&mc, pubkey, seckey);
1304
1099
fprintf(stderr, "init_gnutls_global failed\n");
1305
1100
exitcode = EXIT_FAILURE;
1308
1103
gnutls_initialized = true;
1315
tempdir_created = true;
1316
1106
if(mkdtemp(tempdir) == NULL){
1317
tempdir_created = false;
1318
1107
perror("mkdtemp");
1326
if(not init_gpgme(pubkey, seckey, tempdir)){
1110
tempdir_created = true;
1112
if(not init_gpgme(&mc, pubkey, seckey, tempdir)){
1327
1113
fprintf(stderr, "init_gpgme failed\n");
1328
1114
exitcode = EXIT_FAILURE;
1331
1117
gpgme_initialized = true;
1120
if(interface[0] != '\0'){
1121
if_index = (AvahiIfIndex) if_nametoindex(interface);
1123
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1124
exitcode = EXIT_FAILURE;
1338
1129
if(connect_to != NULL){
1344
1135
exitcode = EXIT_FAILURE;
1354
tmpmax = strtoimax(address+1, &tmp, 10);
1355
if(errno != 0 or tmp == address+1 or *tmp != '\0'
1356
or tmpmax != (uint16_t)tmpmax){
1139
ret = sscanf(address+1, "%" SCNdMAX "%n", &tmpmax, &numchars);
1140
if(ret < 1 or tmpmax != (uint16_t)tmpmax
1141
or address[numchars+1] != '\0'){
1357
1142
fprintf(stderr, "Bad port number\n");
1358
1143
exitcode = EXIT_FAILURE;
1366
1146
port = (uint16_t)tmpmax;
1367
1147
*address = '\0';
1368
1148
address = connect_to;
1381
ret = start_mandos_communication(address, port, if_index, af);
1156
ret = start_mandos_communication(address, port, if_index, &mc,
1383
1159
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;
1424
1207
/* Create the Avahi service browser */
1425
1208
sb = avahi_s_service_browser_new(mc.server, if_index,
1426
AVAHI_PROTO_UNSPEC, "_mandos._tcp",
1427
NULL, 0, browse_callback, NULL);
1209
AVAHI_PROTO_INET6, "_mandos._tcp",
1210
NULL, 0, browse_callback, &mc);
1428
1211
if(sb == NULL){
1429
1212
fprintf(stderr, "Failed to create service browser: %s\n",
1430
1213
avahi_strerror(avahi_server_errno(mc.server)));
1470
1249
gpgme_release(mc.ctx);
1473
/* Take down the network interface */
1474
if(take_down_interface){
1475
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1477
perror("ioctl SIOCGIFFLAGS");
1478
} else if(network.ifr_flags & IFF_UP) {
1479
network.ifr_flags &= ~IFF_UP; /* clear flag */
1480
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1482
perror("ioctl SIOCSIFFLAGS");
1485
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1491
1252
/* Removes the temp directory used by GPGME */
1492
1253
if(tempdir_created){