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 */
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#include <string.h> /* memset(), strcmp(), strlen(),
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strerror(), asprintf(), strcpy() */
71
71
INET_ADDRSTRLEN, INET6_ADDRSTRLEN
73
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#include <unistd.h> /* close(), SEEK_SET, off_t, write(),
74
getuid(), getgid(), setuid(),
74
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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78
#include <argp.h> /* struct argp_option, error_t, struct
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#include <signal.h> /* sigemptyset(), sigaddset(),
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sigaction(), SIGTERM, sig_atomic_t,
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#include <sysexits.h> /* EX_OSERR, EX_USAGE, EX_UNAVAILABLE,
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EX_NOHOST, EX_IOERR, EX_PROTOCOL */
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#include <sys/klog.h> /* klogctl() */
142
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.dh_bits = 1024, .priority = "SECURE256"
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":!CTYPE-X.509:+CTYPE-OPENPGP" };
147
sig_atomic_t quit_now = 0;
148
int signal_received = 0;
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151
* Make additional room in "buffer" for at least BUFFER_SIZE more
147
152
* bytes. "buffer_capacity" is how much is currently allocated,
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479
static int init_gnutls_session(gnutls_session_t *session){
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/* 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);
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502
if(ret != GNUTLS_E_SUCCESS){
487
503
fprintf(stderr, "Syntax error at: %s\n", err);
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504
fprintf(stderr, "GnuTLS error: %s\n",
495
ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,
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ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,
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gnutls_deinit(*session);
518
} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
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519
if(ret != GNUTLS_E_SUCCESS){
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520
fprintf(stderr, "Error setting GnuTLS credentials: %s\n",
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521
safer_gnutls_strerror(ret));
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526
/* ignore client certificate if any. */
505
gnutls_certificate_server_set_request(*session,
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gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);
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gnutls_dh_set_prime_bits(*session, mc.dh_bits);
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535
static void empty_log(__attribute__((unused)) AvahiLogLevel level,
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__attribute__((unused)) const char *txt){}
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sig_atomic_t quit_now = 0;
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int signal_received = 0;
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538
/* Called when a Mandos server is found */
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static int start_mandos_communication(const char *ip, uint16_t port,
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AvahiIfIndex if_index,
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int ret, tcp_sd = -1;
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struct sockaddr_in in;
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struct sockaddr_in6 in6;
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548
char *buffer = NULL;
531
char *decrypted_buffer;
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char *decrypted_buffer = NULL;
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550
size_t buffer_length = 0;
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551
size_t buffer_capacity = 0;
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ssize_t decrypted_buffer_size;
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554
gnutls_session_t session;
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555
int pf; /* Protocol family */
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606
ret = inet_pton(af, ip, &to.in.sin_addr);
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610
perror("inet_pton");
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fprintf(stderr, "Bad address: %s\n", ip);
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620
if(af == AF_INET6){
585
621
to.in6.sin6_port = htons(port); /* Spurious warnings from
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628
if(if_index == AVAHI_IF_UNSPEC){
593
629
fprintf(stderr, "An IPv6 link-local address is incomplete"
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630
" without a network interface\n");
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/* Set the network interface number as scope */
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to.in6.sin6_scope_id = (uint32_t)if_index;
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685
if(af == AF_INET6){
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ret = connect(tcp_sd, &to.in6, sizeof(to));
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688
ret = connect(tcp_sd, &to.in, sizeof(to)); /* IPv4 */
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perror("connect");
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702
const char *out = mandos_protocol_version;
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fprintf(stderr, "Establishing TLS session with %s\n", ip);
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741
gnutls_transport_set_ptr(session, (gnutls_transport_ptr_t) tcp_sd);
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ret = gnutls_handshake(session);
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754
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
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if(ret != GNUTLS_E_SUCCESS){
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801
case GNUTLS_E_AGAIN:
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803
case GNUTLS_E_REHANDSHAKE:
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ret = gnutls_handshake(session);
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811
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
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813
fprintf(stderr, "*** GnuTLS Re-handshake failed ***\n");
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gnutls_perror(ret);
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fprintf(stderr, "Unknown error while reading data from"
730
821
" encrypted session with Mandos server\n");
732
822
gnutls_bye(session, GNUTLS_SHUT_RDWR);
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832
fprintf(stderr, "Closing TLS session\n");
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gnutls_bye(session, GNUTLS_SHUT_RDWR);
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ret = gnutls_bye(session, GNUTLS_SHUT_RDWR);
846
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
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848
if(buffer_length > 0){
849
ssize_t decrypted_buffer_size;
747
850
decrypted_buffer_size = pgp_packet_decrypt(buffer,
749
852
&decrypted_buffer);
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if(decrypted_buffer_size >= 0){
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while(written < (size_t) decrypted_buffer_size){
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862
ret = (int)fwrite(decrypted_buffer + written, 1,
754
863
(size_t)decrypted_buffer_size - written,
756
865
if(ret == 0 and ferror(stdout)){
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868
fprintf(stderr, "Error writing encrypted data: %s\n",
759
869
strerror(errno));
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written += (size_t)ret;
766
free(decrypted_buffer);
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/* Shutdown procedure */
778
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);
782
gnutls_deinit(session);
920
1044
bool gpgme_initialized = false;
921
1045
float delay = 2.5f;
923
struct sigaction old_sigterm_action;
1047
struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };
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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) */
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struct argp_option options[] = {
928
1073
{ .name = "debug", .key = 128,
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1102
.arg = "SECONDS",
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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 },
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{ .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 },
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1114
{ .name = NULL }
963
1117
error_t parse_opt(int key, char *arg,
964
1118
struct argp_state *state){
966
1121
case 128: /* --debug */
983
1138
tmpmax = strtoimax(arg, &tmp, 10);
984
1139
if(errno != 0 or tmp == arg or *tmp != '\0'
985
1140
or tmpmax != (typeof(mc.dh_bits))tmpmax){
986
fprintf(stderr, "Bad number of DH bits\n");
1141
argp_error(state, "Bad number of DH bits");
989
1143
mc.dh_bits = (typeof(mc.dh_bits))tmpmax;
996
1150
delay = strtof(arg, &tmp);
997
1151
if(errno != 0 or tmp == arg or *tmp != '\0'){
998
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);
1007
1170
return ARGP_ERR_UNKNOWN;
1012
1175
struct argp argp = { .options = options, .parser = parse_opt,
1013
1176
.args_doc = "",
1014
1177
.doc = "Mandos client -- Get and decrypt"
1015
1178
" passwords from a Mandos server" };
1016
ret = argp_parse(&argp, argc, argv, 0, 0, NULL);
1017
if(ret == ARGP_ERR_UNKNOWN){
1018
fprintf(stderr, "Unknown error while parsing arguments\n");
1019
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;
1032
1204
mc.simple_poll = avahi_simple_poll_new();
1033
1205
if(mc.simple_poll == NULL){
1034
1206
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1035
exitcode = EXIT_FAILURE;
1207
exitcode = EX_UNAVAILABLE;
1040
1212
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1042
1214
perror("sigaddset");
1043
exitcode = EXIT_FAILURE;
1215
exitcode = EX_OSERR;
1046
1218
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1048
1220
perror("sigaddset");
1049
exitcode = EXIT_FAILURE;
1221
exitcode = EX_OSERR;
1052
1224
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1054
1226
perror("sigaddset");
1055
exitcode = EXIT_FAILURE;
1227
exitcode = EX_OSERR;
1058
1230
/* Need to check if the handler is SIG_IGN before handling:
1062
1234
ret = sigaction(SIGINT, NULL, &old_sigterm_action);
1064
1236
perror("sigaction");
1065
return EXIT_FAILURE;
1067
1239
if(old_sigterm_action.sa_handler != SIG_IGN){
1068
1240
ret = sigaction(SIGINT, &sigterm_action, NULL);
1070
1242
perror("sigaction");
1071
exitcode = EXIT_FAILURE;
1243
exitcode = EX_OSERR;
1075
1247
ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
1077
1249
perror("sigaction");
1078
return EXIT_FAILURE;
1080
1252
if(old_sigterm_action.sa_handler != SIG_IGN){
1081
1253
ret = sigaction(SIGHUP, &sigterm_action, NULL);
1083
1255
perror("sigaction");
1084
exitcode = EXIT_FAILURE;
1256
exitcode = EX_OSERR;
1088
1260
ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
1090
1262
perror("sigaction");
1091
return EXIT_FAILURE;
1093
1265
if(old_sigterm_action.sa_handler != SIG_IGN){
1094
1266
ret = sigaction(SIGTERM, &sigterm_action, NULL);
1096
1268
perror("sigaction");
1097
exitcode = EXIT_FAILURE;
1269
exitcode = EX_OSERR;
1287
/* Re-raise priviliges */
1115
1294
#ifdef __linux__
1116
1295
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1117
messages to mess up the prompt */
1296
messages about the network interface to mess up the prompt */
1118
1297
ret = klogctl(8, NULL, 5);
1119
1298
bool restore_loglevel = true;
1228
1422
ret = init_gnutls_global(pubkey, seckey);
1230
1424
fprintf(stderr, "init_gnutls_global failed\n");
1231
exitcode = EXIT_FAILURE;
1425
exitcode = EX_UNAVAILABLE;
1234
1428
gnutls_initialized = true;
1252
1446
if(not init_gpgme(pubkey, seckey, tempdir)){
1253
1447
fprintf(stderr, "init_gpgme failed\n");
1254
exitcode = EXIT_FAILURE;
1448
exitcode = EX_UNAVAILABLE;
1257
1451
gpgme_initialized = true;
1399
1611
/* Take down the network interface */
1400
1612
if(take_down_interface){
1401
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1613
/* Re-raise priviliges */
1403
perror("ioctl SIOCGIFFLAGS");
1404
} else if(network.ifr_flags & IFF_UP) {
1405
network.ifr_flags &= ~IFF_UP; /* clear flag */
1406
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1408
perror("ioctl SIOCSIFFLAGS");
1411
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 */
1462
1688
sigemptyset(&old_sigterm_action.sa_mask);
1463
1689
old_sigterm_action.sa_handler = SIG_DFL;
1464
ret = sigaction(signal_received, &old_sigterm_action, NULL);
1690
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
1691
&old_sigterm_action,
1466
1694
perror("sigaction");
1468
raise(signal_received);
1697
ret = raise(signal_received);
1698
} while(ret != 0 and errno == EINTR);
1703
TEMP_FAILURE_RETRY(pause());
1471
1706
return exitcode;