43
43
stdout, ferror(), remove() */
44
44
#include <stdint.h> /* uint16_t, uint32_t */
45
45
#include <stddef.h> /* NULL, size_t, ssize_t */
46
#include <stdlib.h> /* free(), EXIT_SUCCESS, EXIT_FAILURE,
46
#include <stdlib.h> /* free(), EXIT_SUCCESS, srand(),
48
48
#include <stdbool.h> /* bool, false, true */
49
49
#include <string.h> /* memset(), strcmp(), strlen(),
50
50
strerror(), asprintf(), strcpy() */
71
71
INET_ADDRSTRLEN, INET6_ADDRSTRLEN
73
73
#include <unistd.h> /* close(), SEEK_SET, off_t, write(),
74
getuid(), getgid(), setuid(),
74
getuid(), getgid(), seteuid(),
76
76
#include <arpa/inet.h> /* inet_pton(), htons */
77
77
#include <iso646.h> /* not, or, and */
78
78
#include <argp.h> /* struct argp_option, error_t, struct
80
80
argp_parse(), ARGP_KEY_ARG,
81
81
ARGP_KEY_END, ARGP_ERR_UNKNOWN */
82
82
#include <signal.h> /* sigemptyset(), sigaddset(),
83
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 */
87
89
#include <sys/klog.h> /* klogctl() */
142
144
.dh_bits = 1024, .priority = "SECURE256"
143
145
":!CTYPE-X.509:+CTYPE-OPENPGP" };
147
sig_atomic_t quit_now = 0;
148
int signal_received = 0;
146
151
* Make additional room in "buffer" for at least BUFFER_SIZE more
147
152
* bytes. "buffer_capacity" is how much is currently allocated,
474
479
static int init_gnutls_session(gnutls_session_t *session){
476
481
/* GnuTLS session creation */
477
ret = gnutls_init(session, GNUTLS_SERVER);
483
ret = gnutls_init(session, GNUTLS_SERVER);
487
} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
478
488
if(ret != GNUTLS_E_SUCCESS){
479
489
fprintf(stderr, "Error in GnuTLS session initialization: %s\n",
480
490
safer_gnutls_strerror(ret));
485
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);
486
502
if(ret != GNUTLS_E_SUCCESS){
487
503
fprintf(stderr, "Syntax error at: %s\n", err);
488
504
fprintf(stderr, "GnuTLS error: %s\n",
495
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);
497
519
if(ret != GNUTLS_E_SUCCESS){
498
520
fprintf(stderr, "Error setting GnuTLS credentials: %s\n",
499
521
safer_gnutls_strerror(ret));
504
526
/* ignore client certificate if any. */
505
gnutls_certificate_server_set_request(*session,
527
gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);
508
529
gnutls_dh_set_prime_bits(*session, mc.dh_bits);
518
539
static int start_mandos_communication(const char *ip, uint16_t port,
519
540
AvahiIfIndex if_index,
542
int ret, tcp_sd = -1;
524
545
struct sockaddr_in in;
525
546
struct sockaddr_in6 in6;
527
548
char *buffer = NULL;
528
char *decrypted_buffer;
549
char *decrypted_buffer = NULL;
529
550
size_t buffer_length = 0;
530
551
size_t buffer_capacity = 0;
531
ssize_t decrypted_buffer_size;
534
554
gnutls_session_t session;
535
555
int pf; /* Protocol family */
571
606
ret = inet_pton(af, ip, &to.in.sin_addr);
574
610
perror("inet_pton");
578
616
fprintf(stderr, "Bad address: %s\n", ip);
581
620
if(af == AF_INET6){
582
621
to.in6.sin6_port = htons(port); /* Spurious warnings from
589
628
if(if_index == AVAHI_IF_UNSPEC){
590
629
fprintf(stderr, "An IPv6 link-local address is incomplete"
591
630
" without a network interface\n");
594
634
/* Set the network interface number as scope */
595
635
to.in6.sin6_scope_id = (uint32_t)if_index;
635
685
if(af == AF_INET6){
636
686
ret = connect(tcp_sd, &to.in6, sizeof(to));
638
688
ret = connect(tcp_sd, &to.in, sizeof(to)); /* IPv4 */
641
692
perror("connect");
645
702
const char *out = mandos_protocol_version;
670
733
fprintf(stderr, "Establishing TLS session with %s\n", ip);
673
741
gnutls_transport_set_ptr(session, (gnutls_transport_ptr_t) tcp_sd);
676
749
ret = gnutls_handshake(session);
677
754
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
679
756
if(ret != GNUTLS_E_SUCCESS){
712
801
case GNUTLS_E_AGAIN:
714
803
case GNUTLS_E_REHANDSHAKE:
716
805
ret = gnutls_handshake(session);
717
811
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
719
813
fprintf(stderr, "*** GnuTLS Re-handshake failed ***\n");
720
814
gnutls_perror(ret);
726
820
fprintf(stderr, "Unknown error while reading data from"
727
821
" encrypted session with Mandos server\n");
729
822
gnutls_bye(session, GNUTLS_SHUT_RDWR);
738
832
fprintf(stderr, "Closing TLS session\n");
741
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);
743
848
if(buffer_length > 0){
849
ssize_t decrypted_buffer_size;
744
850
decrypted_buffer_size = pgp_packet_decrypt(buffer,
746
852
&decrypted_buffer);
747
853
if(decrypted_buffer_size >= 0){
749
856
while(written < (size_t) decrypted_buffer_size){
750
862
ret = (int)fwrite(decrypted_buffer + written, 1,
751
863
(size_t)decrypted_buffer_size - written,
753
865
if(ret == 0 and ferror(stdout)){
755
868
fprintf(stderr, "Error writing encrypted data: %s\n",
756
869
strerror(errno));
761
874
written += (size_t)ret;
763
free(decrypted_buffer);
771
880
/* Shutdown procedure */
775
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);
779
gnutls_deinit(session);
878
sig_atomic_t quit_now = 0;
880
1009
/* stop main loop after sigterm has been called */
881
static void handle_sigterm(__attribute__((unused)) int sig){
1010
static void handle_sigterm(int sig){
1015
signal_received = sig;
886
1016
int old_errno = errno;
887
1017
if(mc.simple_poll != NULL){
888
1018
avahi_simple_poll_quit(mc.simple_poll);
913
1044
bool gpgme_initialized = false;
914
1045
float delay = 2.5f;
916
struct sigaction old_sigterm_action;
1047
struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };
917
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) */
920
1072
struct argp_option options[] = {
921
1073
{ .name = "debug", .key = 128,
950
1102
.arg = "SECONDS",
951
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 },
953
1114
{ .name = NULL }
956
1117
error_t parse_opt(int key, char *arg,
957
1118
struct argp_state *state){
959
1121
case 128: /* --debug */
976
1138
tmpmax = strtoimax(arg, &tmp, 10);
977
1139
if(errno != 0 or tmp == arg or *tmp != '\0'
978
1140
or tmpmax != (typeof(mc.dh_bits))tmpmax){
979
fprintf(stderr, "Bad number of DH bits\n");
1141
argp_error(state, "Bad number of DH bits");
982
1143
mc.dh_bits = (typeof(mc.dh_bits))tmpmax;
989
1150
delay = strtof(arg, &tmp);
990
1151
if(errno != 0 or tmp == arg or *tmp != '\0'){
991
fprintf(stderr, "Bad delay\n");
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);
1000
1170
return ARGP_ERR_UNKNOWN;
1005
1175
struct argp argp = { .options = options, .parser = parse_opt,
1006
1176
.args_doc = "",
1007
1177
.doc = "Mandos client -- Get and decrypt"
1008
1178
" passwords from a Mandos server" };
1009
ret = argp_parse(&argp, argc, argv, 0, 0, NULL);
1010
if(ret == ARGP_ERR_UNKNOWN){
1011
fprintf(stderr, "Unknown error while parsing arguments\n");
1012
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;
1025
1204
mc.simple_poll = avahi_simple_poll_new();
1026
1205
if(mc.simple_poll == NULL){
1027
1206
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1028
exitcode = EXIT_FAILURE;
1207
exitcode = EX_UNAVAILABLE;
1033
1212
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1035
1214
perror("sigaddset");
1036
exitcode = EXIT_FAILURE;
1215
exitcode = EX_OSERR;
1039
1218
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1041
1220
perror("sigaddset");
1042
exitcode = EXIT_FAILURE;
1221
exitcode = EX_OSERR;
1045
1224
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1047
1226
perror("sigaddset");
1048
exitcode = EXIT_FAILURE;
1051
ret = sigaction(SIGTERM, &sigterm_action, &old_sigterm_action);
1053
perror("sigaction");
1054
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;
1058
1274
/* If the interface is down, bring it up */
1059
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 */
1060
1294
#ifdef __linux__
1061
1295
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1062
messages to mess up the prompt */
1296
messages about the network interface to mess up the prompt */
1063
1297
ret = klogctl(8, NULL, 5);
1064
1298
bool restore_loglevel = true;
1096
1336
#endif /* __linux__ */
1097
exitcode = EXIT_FAILURE;
1337
exitcode = EX_OSERR;
1338
/* Lower privileges */
1100
1346
if((network.ifr_flags & IFF_UP) == 0){
1101
1347
network.ifr_flags |= IFF_UP;
1348
take_down_interface = true;
1102
1349
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1351
take_down_interface = false;
1104
1352
perror("ioctl SIOCSIFFLAGS");
1105
exitcode = EXIT_FAILURE;
1353
exitcode = EX_OSERR;
1106
1354
#ifdef __linux__
1107
1355
if(restore_loglevel){
1108
1356
ret = klogctl(7, NULL, 0);
1143
1400
#endif /* __linux__ */
1401
/* Lower privileges */
1403
if(take_down_interface){
1404
/* Lower privileges */
1410
/* Lower privileges permanently */
1160
1422
ret = init_gnutls_global(pubkey, seckey);
1162
1424
fprintf(stderr, "init_gnutls_global failed\n");
1163
exitcode = EXIT_FAILURE;
1425
exitcode = EX_UNAVAILABLE;
1166
1428
gnutls_initialized = true;
1435
tempdir_created = true;
1169
1436
if(mkdtemp(tempdir) == NULL){
1437
tempdir_created = false;
1170
1438
perror("mkdtemp");
1173
tempdir_created = true;
1175
1446
if(not init_gpgme(pubkey, seckey, tempdir)){
1176
1447
fprintf(stderr, "init_gpgme failed\n");
1177
exitcode = EXIT_FAILURE;
1448
exitcode = EX_UNAVAILABLE;
1180
1451
gpgme_initialized = true;
1183
if(interface[0] != '\0'){
1184
if_index = (AvahiIfIndex) if_nametoindex(interface);
1186
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1187
exitcode = EXIT_FAILURE;
1192
1458
if(connect_to != NULL){
1195
1461
char *address = strrchr(connect_to, ':');
1196
1462
if(address == NULL){
1197
1463
fprintf(stderr, "No colon in address\n");
1198
exitcode = EXIT_FAILURE;
1464
exitcode = EX_USAGE;
1203
1474
tmpmax = strtoimax(address+1, &tmp, 10);
1204
1475
if(errno != 0 or tmp == address+1 or *tmp != '\0'
1205
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 */
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;