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
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#include <stdint.h> /* uint16_t, uint32_t */
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#include <stddef.h> /* NULL, size_t, ssize_t */
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#include <stdlib.h> /* free(), EXIT_SUCCESS, EXIT_FAILURE,
46
#include <stdlib.h> /* free(), EXIT_SUCCESS, srand(),
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#include <stdbool.h> /* bool, false, true */
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49
#include <string.h> /* memset(), strcmp(), strlen(),
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strerror(), asprintf(), strcpy() */
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59
#include <fcntl.h> /* open() */
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#include <dirent.h> /* opendir(), struct dirent, readdir()
59
#include <inttypes.h> /* PRIu16, intmax_t, SCNdMAX */
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#include <inttypes.h> /* PRIu16, PRIdMAX, intmax_t,
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#include <assert.h> /* assert() */
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#include <errno.h> /* perror(), errno */
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#include <time.h> /* nanosleep(), time() */
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INET_ADDRSTRLEN, INET6_ADDRSTRLEN
69
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#include <unistd.h> /* close(), SEEK_SET, off_t, write(),
70
getuid(), getgid(), setuid(),
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getuid(), getgid(), seteuid(),
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#include <arpa/inet.h> /* inet_pton(), htons */
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#include <iso646.h> /* not, or, and */
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#include <argp.h> /* struct argp_option, error_t, struct
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argp_parse(), ARGP_KEY_ARG,
77
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ARGP_KEY_END, ARGP_ERR_UNKNOWN */
78
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#include <signal.h> /* sigemptyset(), sigaddset(),
79
sigaction(), SIGTERM, sigaction,
83
sigaction(), SIGTERM, sig_atomic_t,
85
#include <sysexits.h> /* EX_OSERR, EX_USAGE, EX_UNAVAILABLE,
86
EX_NOHOST, EX_IOERR, EX_PROTOCOL */
83
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#include <sys/klog.h> /* klogctl() */
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.dh_bits = 1024, .priority = "SECURE256"
139
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":!CTYPE-X.509:+CTYPE-OPENPGP" };
147
sig_atomic_t quit_now = 0;
148
int signal_received = 0;
142
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* Make additional room in "buffer" for at least BUFFER_SIZE more
143
152
* bytes. "buffer_capacity" is how much is currently allocated,
306
315
gpgme_recipient_t recipient;
307
316
recipient = result->recipients;
309
while(recipient != NULL){
310
fprintf(stderr, "Public key algorithm: %s\n",
311
gpgme_pubkey_algo_name(recipient->pubkey_algo));
312
fprintf(stderr, "Key ID: %s\n", recipient->keyid);
313
fprintf(stderr, "Secret key available: %s\n",
314
recipient->status == GPG_ERR_NO_SECKEY
316
recipient = recipient->next;
317
while(recipient != NULL){
318
fprintf(stderr, "Public key algorithm: %s\n",
319
gpgme_pubkey_algo_name(recipient->pubkey_algo));
320
fprintf(stderr, "Key ID: %s\n", recipient->keyid);
321
fprintf(stderr, "Secret key available: %s\n",
322
recipient->status == GPG_ERR_NO_SECKEY
324
recipient = recipient->next;
472
479
static int init_gnutls_session(gnutls_session_t *session){
474
481
/* GnuTLS session creation */
475
ret = gnutls_init(session, GNUTLS_SERVER);
483
ret = gnutls_init(session, GNUTLS_SERVER);
487
} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
476
488
if(ret != GNUTLS_E_SUCCESS){
477
489
fprintf(stderr, "Error in GnuTLS session initialization: %s\n",
478
490
safer_gnutls_strerror(ret));
483
ret = gnutls_priority_set_direct(*session, mc.priority, &err);
496
ret = gnutls_priority_set_direct(*session, mc.priority, &err);
498
gnutls_deinit(*session);
501
} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
484
502
if(ret != GNUTLS_E_SUCCESS){
485
503
fprintf(stderr, "Syntax error at: %s\n", err);
486
504
fprintf(stderr, "GnuTLS error: %s\n",
493
ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,
512
ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,
515
gnutls_deinit(*session);
518
} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
495
519
if(ret != GNUTLS_E_SUCCESS){
496
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fprintf(stderr, "Error setting GnuTLS credentials: %s\n",
497
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safer_gnutls_strerror(ret));
502
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/* ignore client certificate if any. */
503
gnutls_certificate_server_set_request(*session,
527
gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);
506
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gnutls_dh_set_prime_bits(*session, mc.dh_bits);
516
539
static int start_mandos_communication(const char *ip, uint16_t port,
517
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AvahiIfIndex if_index,
542
int ret, tcp_sd = -1;
522
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struct sockaddr_in in;
523
546
struct sockaddr_in6 in6;
525
548
char *buffer = NULL;
526
char *decrypted_buffer;
549
char *decrypted_buffer = NULL;
527
550
size_t buffer_length = 0;
528
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size_t buffer_capacity = 0;
529
ssize_t decrypted_buffer_size;
532
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gnutls_session_t session;
533
555
int pf; /* Protocol family */
557
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tcp_sd = socket(pf, SOCK_STREAM, 0);
559
590
perror("socket");
563
600
memset(&to, 0, sizeof(to));
564
601
if(af == AF_INET6){
565
to.in6.sin6_family = (uint16_t)af;
602
to.in6.sin6_family = (sa_family_t)af;
566
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ret = inet_pton(af, ip, &to.in6.sin6_addr);
567
604
} else { /* IPv4 */
568
605
to.in.sin_family = (sa_family_t)af;
569
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ret = inet_pton(af, ip, &to.in.sin_addr);
572
610
perror("inet_pton");
576
616
fprintf(stderr, "Bad address: %s\n", ip);
579
620
if(af == AF_INET6){
580
621
to.in6.sin6_port = htons(port); /* Spurious warnings from
587
628
if(if_index == AVAHI_IF_UNSPEC){
588
629
fprintf(stderr, "An IPv6 link-local address is incomplete"
589
630
" without a network interface\n");
592
634
/* Set the network interface number as scope */
593
635
to.in6.sin6_scope_id = (uint32_t)if_index;
633
685
if(af == AF_INET6){
634
686
ret = connect(tcp_sd, &to.in6, sizeof(to));
636
688
ret = connect(tcp_sd, &to.in, sizeof(to)); /* IPv4 */
639
692
perror("connect");
643
702
const char *out = mandos_protocol_version;
668
733
fprintf(stderr, "Establishing TLS session with %s\n", ip);
671
741
gnutls_transport_set_ptr(session, (gnutls_transport_ptr_t) tcp_sd);
674
749
ret = gnutls_handshake(session);
675
754
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
677
756
if(ret != GNUTLS_E_SUCCESS){
710
801
case GNUTLS_E_AGAIN:
712
803
case GNUTLS_E_REHANDSHAKE:
714
805
ret = gnutls_handshake(session);
715
811
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
717
813
fprintf(stderr, "*** GnuTLS Re-handshake failed ***\n");
718
814
gnutls_perror(ret);
724
820
fprintf(stderr, "Unknown error while reading data from"
725
821
" encrypted session with Mandos server\n");
727
822
gnutls_bye(session, GNUTLS_SHUT_RDWR);
736
832
fprintf(stderr, "Closing TLS session\n");
739
gnutls_bye(session, GNUTLS_SHUT_RDWR);
841
ret = gnutls_bye(session, GNUTLS_SHUT_RDWR);
846
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
741
848
if(buffer_length > 0){
849
ssize_t decrypted_buffer_size;
742
850
decrypted_buffer_size = pgp_packet_decrypt(buffer,
744
852
&decrypted_buffer);
745
853
if(decrypted_buffer_size >= 0){
747
856
while(written < (size_t) decrypted_buffer_size){
748
862
ret = (int)fwrite(decrypted_buffer + written, 1,
749
863
(size_t)decrypted_buffer_size - written,
751
865
if(ret == 0 and ferror(stdout)){
753
868
fprintf(stderr, "Error writing encrypted data: %s\n",
754
869
strerror(errno));
759
874
written += (size_t)ret;
761
free(decrypted_buffer);
769
880
/* Shutdown procedure */
773
ret = (int)TEMP_FAILURE_RETRY(close(tcp_sd));
885
free(decrypted_buffer);
888
ret = (int)TEMP_FAILURE_RETRY(close(tcp_sd));
896
gnutls_deinit(session);
777
gnutls_deinit(session);
854
987
the callback function is called the Avahi server will free the
855
988
resolver for us. */
857
if(!(avahi_s_service_resolver_new(mc.server, interface,
858
protocol, name, type, domain,
859
AVAHI_PROTO_INET6, 0,
860
resolve_callback, NULL)))
990
if(avahi_s_service_resolver_new(mc.server, interface, protocol,
991
name, type, domain, protocol, 0,
992
resolve_callback, NULL) == NULL)
861
993
fprintf(stderr, "Avahi: Failed to resolve service '%s': %s\n",
862
994
name, avahi_strerror(avahi_server_errno(mc.server)));
877
sig_atomic_t quit_now = 0;
879
1009
/* stop main loop after sigterm has been called */
880
static void handle_sigterm(__attribute__((unused)) int sig){
1010
static void handle_sigterm(int sig){
1015
signal_received = sig;
885
1016
int old_errno = errno;
886
1017
if(mc.simple_poll != NULL){
887
1018
avahi_simple_poll_quit(mc.simple_poll);
908
1040
const char *seckey = PATHDIR "/" SECKEY;
909
1041
const char *pubkey = PATHDIR "/" PUBKEY;
911
/* Initialize Mandos context */
912
mc = (mandos_context){ .simple_poll = NULL, .server = NULL,
913
.dh_bits = 1024, .priority = "SECURE256"
914
":!CTYPE-X.509:+CTYPE-OPENPGP" };
915
1043
bool gnutls_initialized = false;
916
1044
bool gpgme_initialized = false;
919
struct sigaction old_sigterm_action;
1047
struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };
920
1048
struct sigaction sigterm_action = { .sa_handler = handle_sigterm };
1053
/* Lower any group privileges we might have, just to be safe */
1060
/* Lower user privileges (temporarily) */
923
1072
struct argp_option options[] = {
924
1073
{ .name = "debug", .key = 128,
953
1102
.arg = "SECONDS",
954
1103
.doc = "Maximum delay to wait for interface startup",
1106
* These reproduce what we would get without ARGP_NO_HELP
1108
{ .name = "help", .key = '?',
1109
.doc = "Give this help list", .group = -1 },
1110
{ .name = "usage", .key = -3,
1111
.doc = "Give a short usage message", .group = -1 },
1112
{ .name = "version", .key = 'V',
1113
.doc = "Print program version", .group = -1 },
956
1114
{ .name = NULL }
959
1117
error_t parse_opt(int key, char *arg,
960
1118
struct argp_state *state){
962
1121
case 128: /* --debug */
977
1136
case 129: /* --dh-bits */
978
ret = sscanf(arg, "%" SCNdMAX "%n", &tmpmax, &numchars);
979
if(ret < 1 or tmpmax != (typeof(mc.dh_bits))tmpmax
980
or arg[numchars] != '\0'){
981
fprintf(stderr, "Bad number of DH bits\n");
1138
tmpmax = strtoimax(arg, &tmp, 10);
1139
if(errno != 0 or tmp == arg or *tmp != '\0'
1140
or tmpmax != (typeof(mc.dh_bits))tmpmax){
1141
argp_error(state, "Bad number of DH bits");
984
1143
mc.dh_bits = (typeof(mc.dh_bits))tmpmax;
987
1146
mc.priority = arg;
989
1148
case 131: /* --delay */
990
ret = sscanf(arg, "%lf%n", &delay, &numchars);
991
if(ret < 1 or arg[numchars] != '\0'){
992
fprintf(stderr, "Bad delay\n");
1150
delay = strtof(arg, &tmp);
1151
if(errno != 0 or tmp == arg or *tmp != '\0'){
1152
argp_error(state, "Bad delay");
1156
* These reproduce what we would get without ARGP_NO_HELP
1158
case '?': /* --help */
1159
argp_state_help(state, state->out_stream,
1160
(ARGP_HELP_STD_HELP | ARGP_HELP_EXIT_ERR)
1161
& ~(unsigned int)ARGP_HELP_EXIT_OK);
1162
case -3: /* --usage */
1163
argp_state_help(state, state->out_stream,
1164
ARGP_HELP_USAGE | ARGP_HELP_EXIT_ERR);
1165
case 'V': /* --version */
1166
fprintf(state->out_stream, "%s\n", argp_program_version);
1167
exit(argp_err_exit_status);
1001
1170
return ARGP_ERR_UNKNOWN;
1006
1175
struct argp argp = { .options = options, .parser = parse_opt,
1007
1176
.args_doc = "",
1008
1177
.doc = "Mandos client -- Get and decrypt"
1009
1178
" passwords from a Mandos server" };
1010
ret = argp_parse(&argp, argc, argv, 0, 0, NULL);
1011
if(ret == ARGP_ERR_UNKNOWN){
1012
fprintf(stderr, "Unknown error while parsing arguments\n");
1013
exitcode = EXIT_FAILURE;
1179
ret = argp_parse(&argp, argc, argv,
1180
ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);
1187
perror("argp_parse");
1188
exitcode = EX_OSERR;
1191
exitcode = EX_USAGE;
1026
1204
mc.simple_poll = avahi_simple_poll_new();
1027
1205
if(mc.simple_poll == NULL){
1028
1206
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1029
exitcode = EXIT_FAILURE;
1207
exitcode = EX_UNAVAILABLE;
1034
1212
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1036
1214
perror("sigaddset");
1037
exitcode = EXIT_FAILURE;
1215
exitcode = EX_OSERR;
1040
1218
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1042
1220
perror("sigaddset");
1043
exitcode = EXIT_FAILURE;
1221
exitcode = EX_OSERR;
1046
1224
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1048
1226
perror("sigaddset");
1049
exitcode = EXIT_FAILURE;
1052
ret = sigaction(SIGTERM, &sigterm_action, &old_sigterm_action);
1054
perror("sigaction");
1055
exitcode = EXIT_FAILURE;
1227
exitcode = EX_OSERR;
1230
/* Need to check if the handler is SIG_IGN before handling:
1231
| [[info:libc:Initial Signal Actions]] |
1232
| [[info:libc:Basic Signal Handling]] |
1234
ret = sigaction(SIGINT, NULL, &old_sigterm_action);
1236
perror("sigaction");
1239
if(old_sigterm_action.sa_handler != SIG_IGN){
1240
ret = sigaction(SIGINT, &sigterm_action, NULL);
1242
perror("sigaction");
1243
exitcode = EX_OSERR;
1247
ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
1249
perror("sigaction");
1252
if(old_sigterm_action.sa_handler != SIG_IGN){
1253
ret = sigaction(SIGHUP, &sigterm_action, NULL);
1255
perror("sigaction");
1256
exitcode = EX_OSERR;
1260
ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
1262
perror("sigaction");
1265
if(old_sigterm_action.sa_handler != SIG_IGN){
1266
ret = sigaction(SIGTERM, &sigterm_action, NULL);
1268
perror("sigaction");
1269
exitcode = EX_OSERR;
1059
1274
/* If the interface is down, bring it up */
1060
1275
if(interface[0] != '\0'){
1276
if_index = (AvahiIfIndex) if_nametoindex(interface);
1278
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1279
exitcode = EX_UNAVAILABLE;
1287
/* Re-raise priviliges */
1061
1294
#ifdef __linux__
1062
1295
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1063
messages to mess up the prompt */
1296
messages about the network interface to mess up the prompt */
1064
1297
ret = klogctl(8, NULL, 5);
1065
1298
bool restore_loglevel = true;
1097
1336
#endif /* __linux__ */
1098
exitcode = EXIT_FAILURE;
1337
exitcode = EX_OSERR;
1338
/* Lower privileges */
1101
1346
if((network.ifr_flags & IFF_UP) == 0){
1102
1347
network.ifr_flags |= IFF_UP;
1348
take_down_interface = true;
1103
1349
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1351
take_down_interface = false;
1105
1352
perror("ioctl SIOCSIFFLAGS");
1106
exitcode = EXIT_FAILURE;
1353
exitcode = EX_OSERR;
1107
1354
#ifdef __linux__
1108
1355
if(restore_loglevel){
1109
1356
ret = klogctl(7, NULL, 0);
1144
1400
#endif /* __linux__ */
1401
/* Lower privileges */
1403
if(take_down_interface){
1404
/* Lower privileges */
1410
/* Lower privileges permanently */
1161
1422
ret = init_gnutls_global(pubkey, seckey);
1163
1424
fprintf(stderr, "init_gnutls_global failed\n");
1164
exitcode = EXIT_FAILURE;
1425
exitcode = EX_UNAVAILABLE;
1167
1428
gnutls_initialized = true;
1435
tempdir_created = true;
1170
1436
if(mkdtemp(tempdir) == NULL){
1437
tempdir_created = false;
1171
1438
perror("mkdtemp");
1174
tempdir_created = true;
1176
1446
if(not init_gpgme(pubkey, seckey, tempdir)){
1177
1447
fprintf(stderr, "init_gpgme failed\n");
1178
exitcode = EXIT_FAILURE;
1448
exitcode = EX_UNAVAILABLE;
1181
1451
gpgme_initialized = true;
1184
if(interface[0] != '\0'){
1185
if_index = (AvahiIfIndex) if_nametoindex(interface);
1187
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1188
exitcode = EXIT_FAILURE;
1193
1458
if(connect_to != NULL){
1196
1461
char *address = strrchr(connect_to, ':');
1197
1462
if(address == NULL){
1198
1463
fprintf(stderr, "No colon in address\n");
1199
exitcode = EXIT_FAILURE;
1464
exitcode = EX_USAGE;
1203
ret = sscanf(address+1, "%" SCNdMAX "%n", &tmpmax, &numchars);
1204
if(ret < 1 or tmpmax != (uint16_t)tmpmax
1205
or address[numchars+1] != '\0'){
1474
tmpmax = strtoimax(address+1, &tmp, 10);
1475
if(errno != 0 or tmp == address+1 or *tmp != '\0'
1476
or tmpmax != (uint16_t)tmpmax){
1206
1477
fprintf(stderr, "Bad port number\n");
1207
exitcode = EXIT_FAILURE;
1478
exitcode = EX_USAGE;
1210
1486
port = (uint16_t)tmpmax;
1211
1487
*address = '\0';
1212
1488
address = connect_to;
1220
1501
ret = start_mandos_communication(address, port, if_index, af);
1222
exitcode = EXIT_FAILURE;
1507
exitcode = EX_NOHOST;
1510
exitcode = EX_USAGE;
1513
exitcode = EX_IOERR;
1516
exitcode = EX_PROTOCOL;
1519
exitcode = EX_OSERR;
1224
1523
exitcode = EXIT_SUCCESS;
1230
1533
AvahiServerConfig config;
1231
1534
/* Do not publish any local Zeroconf records */
1248
1551
if(mc.server == NULL){
1249
1552
fprintf(stderr, "Failed to create Avahi server: %s\n",
1250
1553
avahi_strerror(error));
1251
exitcode = EXIT_FAILURE;
1554
exitcode = EX_UNAVAILABLE;
1255
1562
/* Create the Avahi service browser */
1256
1563
sb = avahi_s_service_browser_new(mc.server, if_index,
1257
AVAHI_PROTO_INET6, "_mandos._tcp",
1564
AVAHI_PROTO_UNSPEC, "_mandos._tcp",
1258
1565
NULL, 0, browse_callback, NULL);
1259
1566
if(sb == NULL){
1260
1567
fprintf(stderr, "Failed to create service browser: %s\n",
1261
1568
avahi_strerror(avahi_server_errno(mc.server)));
1262
exitcode = EXIT_FAILURE;
1569
exitcode = EX_UNAVAILABLE;
1297
1608
gpgme_release(mc.ctx);
1611
/* Take down the network interface */
1612
if(take_down_interface){
1613
/* Re-raise priviliges */
1620
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1622
perror("ioctl SIOCGIFFLAGS");
1623
} else if(network.ifr_flags & IFF_UP) {
1624
network.ifr_flags &= ~(short)IFF_UP; /* clear flag */
1625
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1627
perror("ioctl SIOCSIFFLAGS");
1630
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1634
/* Lower privileges permanently */
1300
1643
/* Removes the temp directory used by GPGME */
1301
1644
if(tempdir_created){
1688
sigemptyset(&old_sigterm_action.sa_mask);
1689
old_sigterm_action.sa_handler = SIG_DFL;
1690
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
1691
&old_sigterm_action,
1694
perror("sigaction");
1697
ret = raise(signal_received);
1698
} while(ret != 0 and errno == EINTR);
1703
TEMP_FAILURE_RETRY(pause());
1344
1706
return exitcode;