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
82
82
#include <signal.h> /* sigemptyset(), sigaddset(),
83
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);
514
535
static void empty_log(__attribute__((unused)) AvahiLogLevel level,
515
536
__attribute__((unused)) const char *txt){}
517
sig_atomic_t quit_now = 0;
518
int signal_received = 0;
520
538
/* Called when a Mandos server is found */
521
539
static int start_mandos_communication(const char *ip, uint16_t port,
522
540
AvahiIfIndex if_index,
528
546
struct sockaddr_in6 in6;
530
548
char *buffer = NULL;
531
char *decrypted_buffer;
549
char *decrypted_buffer = NULL;
532
550
size_t buffer_length = 0;
533
551
size_t buffer_capacity = 0;
534
ssize_t decrypted_buffer_size;
537
554
gnutls_session_t session;
538
555
int pf; /* Protocol family */
603
628
if(if_index == AVAHI_IF_UNSPEC){
604
629
fprintf(stderr, "An IPv6 link-local address is incomplete"
605
630
" without a network interface\n");
609
634
/* Set the network interface number as scope */
764
801
case GNUTLS_E_AGAIN:
766
803
case GNUTLS_E_REHANDSHAKE:
768
805
ret = gnutls_handshake(session);
773
811
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
775
813
fprintf(stderr, "*** GnuTLS Re-handshake failed ***\n");
776
814
gnutls_perror(ret);
782
820
fprintf(stderr, "Unknown error while reading data from"
783
821
" encrypted session with Mandos server\n");
785
822
gnutls_bye(session, GNUTLS_SHUT_RDWR);
801
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);
807
848
if(buffer_length > 0){
849
ssize_t decrypted_buffer_size;
808
850
decrypted_buffer_size = pgp_packet_decrypt(buffer,
810
852
&decrypted_buffer);
811
853
if(decrypted_buffer_size >= 0){
813
856
while(written < (size_t) decrypted_buffer_size){
819
863
(size_t)decrypted_buffer_size - written,
821
865
if(ret == 0 and ferror(stdout)){
823
868
fprintf(stderr, "Error writing encrypted data: %s\n",
824
869
strerror(errno));
829
874
written += (size_t)ret;
831
free(decrypted_buffer);
839
880
/* Shutdown procedure */
844
ret = (int)TEMP_FAILURE_RETRY(close(tcp_sd));
849
gnutls_deinit(session);
885
free(decrypted_buffer);
888
ret = (int)TEMP_FAILURE_RETRY(close(tcp_sd));
896
gnutls_deinit(session);
994
1044
bool gpgme_initialized = false;
995
1045
float delay = 2.5f;
997
struct sigaction old_sigterm_action;
1047
struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };
998
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) */
1001
1072
struct argp_option options[] = {
1002
1073
{ .name = "debug", .key = 128,
1031
1102
.arg = "SECONDS",
1032
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 },
1034
1114
{ .name = NULL }
1037
1117
error_t parse_opt(int key, char *arg,
1038
1118
struct argp_state *state){
1040
1121
case 128: /* --debug */
1057
1138
tmpmax = strtoimax(arg, &tmp, 10);
1058
1139
if(errno != 0 or tmp == arg or *tmp != '\0'
1059
1140
or tmpmax != (typeof(mc.dh_bits))tmpmax){
1060
fprintf(stderr, "Bad number of DH bits\n");
1141
argp_error(state, "Bad number of DH bits");
1063
1143
mc.dh_bits = (typeof(mc.dh_bits))tmpmax;
1070
1150
delay = strtof(arg, &tmp);
1071
1151
if(errno != 0 or tmp == arg or *tmp != '\0'){
1072
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);
1081
1170
return ARGP_ERR_UNKNOWN;
1086
1175
struct argp argp = { .options = options, .parser = parse_opt,
1087
1176
.args_doc = "",
1088
1177
.doc = "Mandos client -- Get and decrypt"
1089
1178
" passwords from a Mandos server" };
1090
ret = argp_parse(&argp, argc, argv, 0, 0, NULL);
1091
if(ret == ARGP_ERR_UNKNOWN){
1092
fprintf(stderr, "Unknown error while parsing arguments\n");
1093
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;
1106
1204
mc.simple_poll = avahi_simple_poll_new();
1107
1205
if(mc.simple_poll == NULL){
1108
1206
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1109
exitcode = EXIT_FAILURE;
1207
exitcode = EX_UNAVAILABLE;
1114
1212
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1116
1214
perror("sigaddset");
1117
exitcode = EXIT_FAILURE;
1215
exitcode = EX_OSERR;
1120
1218
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1122
1220
perror("sigaddset");
1123
exitcode = EXIT_FAILURE;
1221
exitcode = EX_OSERR;
1126
1224
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1128
1226
perror("sigaddset");
1129
exitcode = EXIT_FAILURE;
1227
exitcode = EX_OSERR;
1132
1230
/* Need to check if the handler is SIG_IGN before handling:
1136
1234
ret = sigaction(SIGINT, NULL, &old_sigterm_action);
1138
1236
perror("sigaction");
1139
return EXIT_FAILURE;
1141
1239
if(old_sigterm_action.sa_handler != SIG_IGN){
1142
1240
ret = sigaction(SIGINT, &sigterm_action, NULL);
1144
1242
perror("sigaction");
1145
exitcode = EXIT_FAILURE;
1243
exitcode = EX_OSERR;
1149
1247
ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
1151
1249
perror("sigaction");
1152
return EXIT_FAILURE;
1154
1252
if(old_sigterm_action.sa_handler != SIG_IGN){
1155
1253
ret = sigaction(SIGHUP, &sigterm_action, NULL);
1157
1255
perror("sigaction");
1158
exitcode = EXIT_FAILURE;
1256
exitcode = EX_OSERR;
1162
1260
ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
1164
1262
perror("sigaction");
1165
return EXIT_FAILURE;
1167
1265
if(old_sigterm_action.sa_handler != SIG_IGN){
1168
1266
ret = sigaction(SIGTERM, &sigterm_action, NULL);
1170
1268
perror("sigaction");
1171
exitcode = EXIT_FAILURE;
1269
exitcode = EX_OSERR;
1287
/* Re-raise priviliges */
1189
1294
#ifdef __linux__
1190
1295
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1191
messages to mess up the prompt */
1296
messages about the network interface to mess up the prompt */
1192
1297
ret = klogctl(8, NULL, 5);
1193
1298
bool restore_loglevel = true;
1302
1422
ret = init_gnutls_global(pubkey, seckey);
1304
1424
fprintf(stderr, "init_gnutls_global failed\n");
1305
exitcode = EXIT_FAILURE;
1425
exitcode = EX_UNAVAILABLE;
1308
1428
gnutls_initialized = true;
1326
1446
if(not init_gpgme(pubkey, seckey, tempdir)){
1327
1447
fprintf(stderr, "init_gpgme failed\n");
1328
exitcode = EXIT_FAILURE;
1448
exitcode = EX_UNAVAILABLE;
1331
1451
gpgme_initialized = true;
1473
1611
/* Take down the network interface */
1474
1612
if(take_down_interface){
1475
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1613
/* Re-raise priviliges */
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));
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 */
1536
1688
sigemptyset(&old_sigterm_action.sa_mask);
1537
1689
old_sigterm_action.sa_handler = SIG_DFL;
1538
ret = sigaction(signal_received, &old_sigterm_action, NULL);
1690
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
1691
&old_sigterm_action,
1540
1694
perror("sigaction");
1542
raise(signal_received);
1697
ret = raise(signal_received);
1698
} while(ret != 0 and errno == EINTR);
1703
TEMP_FAILURE_RETRY(pause());
1545
1706
return exitcode;