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(),
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48
#include <stdbool.h> /* bool, false, true */
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49
#include <string.h> /* memset(), strcmp(), strlen(),
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50
strerror(), asprintf(), strcpy() */
71
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INET_ADDRSTRLEN, INET6_ADDRSTRLEN
73
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#include <unistd.h> /* close(), SEEK_SET, off_t, write(),
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getuid(), getgid(), setuid(),
74
getuid(), getgid(), seteuid(),
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76
#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
80
80
argp_parse(), ARGP_KEY_ARG,
81
81
ARGP_KEY_END, ARGP_ERR_UNKNOWN */
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82
#include <signal.h> /* sigemptyset(), sigaddset(),
83
sigaction(), SIGTERM, sigaction,
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sigaction(), SIGTERM, sig_atomic_t,
85
#include <sysexits.h> /* EX_OSERR, EX_USAGE, EX_UNAVAILABLE,
86
EX_NOHOST, EX_IOERR, EX_PROTOCOL */
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#include <sys/klog.h> /* klogctl() */
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144
.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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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){
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489
fprintf(stderr, "Error in GnuTLS session initialization: %s\n",
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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,
512
ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,
515
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,
527
gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);
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529
gnutls_dh_set_prime_bits(*session, mc.dh_bits);
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539
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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546
struct sockaddr_in6 in6;
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548
char *buffer = NULL;
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char *decrypted_buffer;
549
char *decrypted_buffer = NULL;
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550
size_t buffer_length = 0;
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551
size_t buffer_capacity = 0;
531
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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616
fprintf(stderr, "Bad address: %s\n", ip);
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620
if(af == AF_INET6){
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621
to.in6.sin6_port = htons(port); /* Spurious warnings from
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628
if(if_index == AVAHI_IF_UNSPEC){
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629
fprintf(stderr, "An IPv6 link-local address is incomplete"
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630
" without a network interface\n");
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634
/* Set the network interface number as scope */
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635
to.in6.sin6_scope_id = (uint32_t)if_index;
635
685
if(af == AF_INET6){
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686
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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692
perror("connect");
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702
const char *out = mandos_protocol_version;
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733
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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749
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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805
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"
727
821
" encrypted session with Mandos server\n");
729
822
gnutls_bye(session, GNUTLS_SHUT_RDWR);
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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);
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if(buffer_length > 0){
849
ssize_t decrypted_buffer_size;
744
850
decrypted_buffer_size = pgp_packet_decrypt(buffer,
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852
&decrypted_buffer);
747
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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,
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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));
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874
written += (size_t)ret;
763
free(decrypted_buffer);
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/* 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);
783
sig_atomic_t quit_now = 0;
785
906
static void resolve_callback(AvahiSServiceResolver *r,
786
907
AvahiIfIndex interface,
787
908
AvahiProtocol proto,
884
1009
/* stop main loop after sigterm has been called */
885
static void handle_sigterm(__attribute__((unused)) int sig){
1010
static void handle_sigterm(int sig){
1015
signal_received = sig;
890
1016
int old_errno = errno;
891
1017
if(mc.simple_poll != NULL){
892
1018
avahi_simple_poll_quit(mc.simple_poll);
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1044
bool gpgme_initialized = false;
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float delay = 2.5f;
921
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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1072
struct argp_option options[] = {
926
1073
{ .name = "debug", .key = 128,
955
1102
.arg = "SECONDS",
956
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 },
958
1114
{ .name = NULL }
961
1117
error_t parse_opt(int key, char *arg,
962
1118
struct argp_state *state){
964
1121
case 128: /* --debug */
981
1138
tmpmax = strtoimax(arg, &tmp, 10);
982
1139
if(errno != 0 or tmp == arg or *tmp != '\0'
983
1140
or tmpmax != (typeof(mc.dh_bits))tmpmax){
984
fprintf(stderr, "Bad number of DH bits\n");
1141
argp_error(state, "Bad number of DH bits");
987
1143
mc.dh_bits = (typeof(mc.dh_bits))tmpmax;
994
1150
delay = strtof(arg, &tmp);
995
1151
if(errno != 0 or tmp == arg or *tmp != '\0'){
996
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);
1005
1170
return ARGP_ERR_UNKNOWN;
1010
1175
struct argp argp = { .options = options, .parser = parse_opt,
1011
1176
.args_doc = "",
1012
1177
.doc = "Mandos client -- Get and decrypt"
1013
1178
" passwords from a Mandos server" };
1014
ret = argp_parse(&argp, argc, argv, 0, 0, NULL);
1015
if(ret == ARGP_ERR_UNKNOWN){
1016
fprintf(stderr, "Unknown error while parsing arguments\n");
1017
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;
1030
1204
mc.simple_poll = avahi_simple_poll_new();
1031
1205
if(mc.simple_poll == NULL){
1032
1206
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1033
exitcode = EXIT_FAILURE;
1207
exitcode = EX_UNAVAILABLE;
1038
1212
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1040
1214
perror("sigaddset");
1041
exitcode = EXIT_FAILURE;
1215
exitcode = EX_OSERR;
1044
1218
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1046
1220
perror("sigaddset");
1047
exitcode = EXIT_FAILURE;
1221
exitcode = EX_OSERR;
1050
1224
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1052
1226
perror("sigaddset");
1053
exitcode = EXIT_FAILURE;
1056
ret = sigaction(SIGTERM, &sigterm_action, &old_sigterm_action);
1058
perror("sigaction");
1059
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;
1063
1274
/* If the interface is down, bring it up */
1064
1275
if(interface[0] != '\0'){
1065
1276
if_index = (AvahiIfIndex) if_nametoindex(interface);
1066
1277
if(if_index == 0){
1067
1278
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1068
exitcode = EXIT_FAILURE;
1279
exitcode = EX_UNAVAILABLE;
1287
/* Re-raise priviliges */
1076
1294
#ifdef __linux__
1077
1295
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1078
messages to mess up the prompt */
1296
messages about the network interface to mess up the prompt */
1079
1297
ret = klogctl(8, NULL, 5);
1080
1298
bool restore_loglevel = true;
1189
1422
ret = init_gnutls_global(pubkey, seckey);
1191
1424
fprintf(stderr, "init_gnutls_global failed\n");
1192
exitcode = EXIT_FAILURE;
1425
exitcode = EX_UNAVAILABLE;
1195
1428
gnutls_initialized = true;
1213
1446
if(not init_gpgme(pubkey, seckey, tempdir)){
1214
1447
fprintf(stderr, "init_gpgme failed\n");
1215
exitcode = EXIT_FAILURE;
1448
exitcode = EX_UNAVAILABLE;
1218
1451
gpgme_initialized = true;
1360
1611
/* Take down the network interface */
1361
1612
if(take_down_interface){
1362
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1613
/* Re-raise priviliges */
1364
perror("ioctl SIOCGIFFLAGS");
1365
} else if(network.ifr_flags & IFF_UP) {
1366
network.ifr_flags &= ~IFF_UP; /* clear flag */
1367
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1369
perror("ioctl SIOCSIFFLAGS");
1372
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 */
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());
1422
1706
return exitcode;