9
9
* "browse_callback", and parts of "main".
11
11
* Everything else is
12
* Copyright © 2008,2009 Teddy Hogeborn
13
* Copyright © 2008,2009 Björn Påhlsson
12
* Copyright © 2008-2011 Teddy Hogeborn
13
* Copyright © 2008-2011 Björn Påhlsson
15
15
* This program is free software: you can redistribute it and/or
16
16
* modify it under the terms of the GNU General Public License as
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() */
64
64
#include <assert.h> /* assert() */
65
65
#include <errno.h> /* perror(), errno */
66
#include <time.h> /* nanosleep(), time() */
66
#include <time.h> /* nanosleep(), time(), sleep() */
67
67
#include <net/if.h> /* ioctl, ifreq, SIOCGIFFLAGS, IFF_UP,
68
68
SIOCSIFFLAGS, if_indextoname(),
69
69
if_nametoindex(), IF_NAMESIZE */
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
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#include <arpa/inet.h> /* inet_pton(), htons */
77
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#include <iso646.h> /* not, or, and */
78
78
#include <argp.h> /* struct argp_option, error_t, struct
80
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argp_parse(), ARGP_KEY_ARG,
81
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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() */
125
127
static const char mandos_protocol_version[] = "1";
126
128
const char *argp_program_version = "mandos-client " VERSION;
127
129
const char *argp_program_bug_address = "<mandos@fukt.bsnet.se>";
130
static const char sys_class_net[] = "/sys/class/net";
131
char *connect_to = NULL;
129
133
/* Used for passing in values through the Avahi callback functions */
142
146
.dh_bits = 1024, .priority = "SECURE256"
143
147
":!CTYPE-X.509:+CTYPE-OPENPGP" };
149
sig_atomic_t quit_now = 0;
150
int signal_received = 0;
146
153
* Make additional room in "buffer" for at least BUFFER_SIZE more
147
154
* bytes. "buffer_capacity" is how much is currently allocated,
474
481
static int init_gnutls_session(gnutls_session_t *session){
476
483
/* GnuTLS session creation */
477
ret = gnutls_init(session, GNUTLS_SERVER);
485
ret = gnutls_init(session, GNUTLS_SERVER);
489
} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
478
490
if(ret != GNUTLS_E_SUCCESS){
479
491
fprintf(stderr, "Error in GnuTLS session initialization: %s\n",
480
492
safer_gnutls_strerror(ret));
485
ret = gnutls_priority_set_direct(*session, mc.priority, &err);
498
ret = gnutls_priority_set_direct(*session, mc.priority, &err);
500
gnutls_deinit(*session);
503
} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
486
504
if(ret != GNUTLS_E_SUCCESS){
487
505
fprintf(stderr, "Syntax error at: %s\n", err);
488
506
fprintf(stderr, "GnuTLS error: %s\n",
495
ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,
514
ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,
517
gnutls_deinit(*session);
520
} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
497
521
if(ret != GNUTLS_E_SUCCESS){
498
522
fprintf(stderr, "Error setting GnuTLS credentials: %s\n",
499
523
safer_gnutls_strerror(ret));
504
528
/* ignore client certificate if any. */
505
gnutls_certificate_server_set_request(*session,
529
gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);
508
531
gnutls_dh_set_prime_bits(*session, mc.dh_bits);
518
541
static int start_mandos_communication(const char *ip, uint16_t port,
519
542
AvahiIfIndex if_index,
544
int ret, tcp_sd = -1;
524
547
struct sockaddr_in in;
525
548
struct sockaddr_in6 in6;
527
550
char *buffer = NULL;
528
char *decrypted_buffer;
551
char *decrypted_buffer = NULL;
529
552
size_t buffer_length = 0;
530
553
size_t buffer_capacity = 0;
531
ssize_t decrypted_buffer_size;
534
556
gnutls_session_t session;
535
557
int pf; /* Protocol family */
589
630
if(if_index == AVAHI_IF_UNSPEC){
590
631
fprintf(stderr, "An IPv6 link-local address is incomplete"
591
632
" without a network interface\n");
594
636
/* Set the network interface number as scope */
595
637
to.in6.sin6_scope_id = (uint32_t)if_index;
635
687
if(af == AF_INET6){
636
688
ret = connect(tcp_sd, &to.in6, sizeof(to));
638
690
ret = connect(tcp_sd, &to.in, sizeof(to)); /* IPv4 */
693
if ((errno != ECONNREFUSED and errno != ENETUNREACH) or debug){
645
706
const char *out = mandos_protocol_version;
670
737
fprintf(stderr, "Establishing TLS session with %s\n", ip);
673
745
gnutls_transport_set_ptr(session, (gnutls_transport_ptr_t) tcp_sd);
676
753
ret = gnutls_handshake(session);
677
758
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
679
760
if(ret != GNUTLS_E_SUCCESS){
712
805
case GNUTLS_E_AGAIN:
714
807
case GNUTLS_E_REHANDSHAKE:
716
809
ret = gnutls_handshake(session);
717
815
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
719
817
fprintf(stderr, "*** GnuTLS Re-handshake failed ***\n");
720
818
gnutls_perror(ret);
726
824
fprintf(stderr, "Unknown error while reading data from"
727
825
" encrypted session with Mandos server\n");
729
826
gnutls_bye(session, GNUTLS_SHUT_RDWR);
738
836
fprintf(stderr, "Closing TLS session\n");
741
gnutls_bye(session, GNUTLS_SHUT_RDWR);
845
ret = gnutls_bye(session, GNUTLS_SHUT_RDWR);
850
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
743
852
if(buffer_length > 0){
853
ssize_t decrypted_buffer_size;
744
854
decrypted_buffer_size = pgp_packet_decrypt(buffer,
746
856
&decrypted_buffer);
747
857
if(decrypted_buffer_size >= 0){
749
860
while(written < (size_t) decrypted_buffer_size){
750
866
ret = (int)fwrite(decrypted_buffer + written, 1,
751
867
(size_t)decrypted_buffer_size - written,
753
869
if(ret == 0 and ferror(stdout)){
755
872
fprintf(stderr, "Error writing encrypted data: %s\n",
756
873
strerror(errno));
761
878
written += (size_t)ret;
763
free(decrypted_buffer);
771
884
/* Shutdown procedure */
775
ret = (int)TEMP_FAILURE_RETRY(close(tcp_sd));
889
free(decrypted_buffer);
892
ret = (int)TEMP_FAILURE_RETRY(close(tcp_sd));
900
gnutls_deinit(session);
779
gnutls_deinit(session);
878
sig_atomic_t quit_now = 0;
880
1013
/* stop main loop after sigterm has been called */
881
static void handle_sigterm(__attribute__((unused)) int sig){
1014
static void handle_sigterm(int sig){
1019
signal_received = sig;
886
1020
int old_errno = errno;
887
1021
if(mc.simple_poll != NULL){
888
1022
avahi_simple_poll_quit(mc.simple_poll);
890
1024
errno = old_errno;
1028
* This function determines if a directory entry in /sys/class/net
1029
* corresponds to an acceptable network device.
1030
* (This function is passed to scandir(3) as a filter function.)
1032
int good_interface(const struct dirent *if_entry){
1034
char *flagname = NULL;
1035
int ret = asprintf(&flagname, "%s/%s/flags", sys_class_net,
1041
if(if_entry->d_name[0] == '.'){
1044
int flags_fd = (int)TEMP_FAILURE_RETRY(open(flagname, O_RDONLY));
1049
typedef short ifreq_flags; /* ifreq.ifr_flags in netdevice(7) */
1050
/* read line from flags_fd */
1051
ssize_t to_read = (sizeof(ifreq_flags)*2)+3; /* "0x1003\n" */
1052
char *flagstring = malloc((size_t)to_read+1); /* +1 for final \0 */
1053
flagstring[(size_t)to_read] = '\0';
1054
if(flagstring == NULL){
1060
ssret = (ssize_t)TEMP_FAILURE_RETRY(read(flags_fd, flagstring,
1077
tmpmax = strtoimax(flagstring, &tmp, 0);
1078
if(errno != 0 or tmp == flagstring or (*tmp != '\0'
1079
and not (isspace(*tmp)))
1080
or tmpmax != (ifreq_flags)tmpmax){
1082
fprintf(stderr, "Invalid flags \"%s\" for interface \"%s\"\n",
1083
flagstring, if_entry->d_name);
1089
ifreq_flags flags = (ifreq_flags)tmpmax;
1090
/* Reject the loopback device */
1091
if(flags & IFF_LOOPBACK){
1093
fprintf(stderr, "Rejecting loopback interface \"%s\"\n",
1098
/* Accept point-to-point devices only if connect_to is specified */
1099
if(connect_to != NULL and (flags & IFF_POINTOPOINT)){
1101
fprintf(stderr, "Accepting point-to-point interface \"%s\"\n",
1106
/* Otherwise, reject non-broadcast-capable devices */
1107
if(not (flags & IFF_BROADCAST)){
1109
fprintf(stderr, "Rejecting non-broadcast interface \"%s\"\n",
1114
/* Accept this device */
1116
fprintf(stderr, "Interface \"%s\" is acceptable\n",
893
1122
int main(int argc, char *argv[]){
894
1123
AvahiSServiceBrowser *sb = NULL;
897
1126
intmax_t tmpmax;
899
1128
int exitcode = EXIT_SUCCESS;
900
const char *interface = "eth0";
1129
const char *interface = "";
901
1130
struct ifreq network;
903
bool interface_taken_up = false;
1132
bool take_down_interface = false;
906
char *connect_to = NULL;
907
1135
char tempdir[] = "/tmp/mandosXXXXXX";
908
1136
bool tempdir_created = false;
909
1137
AvahiIfIndex if_index = AVAHI_IF_UNSPEC;
914
1142
bool gpgme_initialized = false;
915
1143
float delay = 2.5f;
917
struct sigaction old_sigterm_action;
1145
struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };
918
1146
struct sigaction sigterm_action = { .sa_handler = handle_sigterm };
1151
/* Lower any group privileges we might have, just to be safe */
1158
/* Lower user privileges (temporarily) */
921
1170
struct argp_option options[] = {
922
1171
{ .name = "debug", .key = 128,
951
1200
.arg = "SECONDS",
952
1201
.doc = "Maximum delay to wait for interface startup",
1204
* These reproduce what we would get without ARGP_NO_HELP
1206
{ .name = "help", .key = '?',
1207
.doc = "Give this help list", .group = -1 },
1208
{ .name = "usage", .key = -3,
1209
.doc = "Give a short usage message", .group = -1 },
1210
{ .name = "version", .key = 'V',
1211
.doc = "Print program version", .group = -1 },
954
1212
{ .name = NULL }
957
1215
error_t parse_opt(int key, char *arg,
958
1216
struct argp_state *state){
960
1219
case 128: /* --debug */
977
1236
tmpmax = strtoimax(arg, &tmp, 10);
978
1237
if(errno != 0 or tmp == arg or *tmp != '\0'
979
1238
or tmpmax != (typeof(mc.dh_bits))tmpmax){
980
fprintf(stderr, "Bad number of DH bits\n");
1239
argp_error(state, "Bad number of DH bits");
983
1241
mc.dh_bits = (typeof(mc.dh_bits))tmpmax;
990
1248
delay = strtof(arg, &tmp);
991
1249
if(errno != 0 or tmp == arg or *tmp != '\0'){
992
fprintf(stderr, "Bad delay\n");
1250
argp_error(state, "Bad delay");
1254
* These reproduce what we would get without ARGP_NO_HELP
1256
case '?': /* --help */
1257
argp_state_help(state, state->out_stream,
1258
(ARGP_HELP_STD_HELP | ARGP_HELP_EXIT_ERR)
1259
& ~(unsigned int)ARGP_HELP_EXIT_OK);
1260
case -3: /* --usage */
1261
argp_state_help(state, state->out_stream,
1262
ARGP_HELP_USAGE | ARGP_HELP_EXIT_ERR);
1263
case 'V': /* --version */
1264
fprintf(state->out_stream, "%s\n", argp_program_version);
1265
exit(argp_err_exit_status);
1001
1268
return ARGP_ERR_UNKNOWN;
1006
1273
struct argp argp = { .options = options, .parser = parse_opt,
1007
1274
.args_doc = "",
1008
1275
.doc = "Mandos client -- Get and decrypt"
1009
1276
" 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;
1277
ret = argp_parse(&argp, argc, argv,
1278
ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);
1285
perror("argp_parse");
1286
exitcode = EX_OSERR;
1289
exitcode = EX_USAGE;
1019
1295
avahi_set_log_function(empty_log);
1298
if(interface[0] == '\0'){
1299
struct dirent **direntries;
1300
ret = scandir(sys_class_net, &direntries, good_interface,
1303
/* Pick the first good interface */
1304
interface = strdup(direntries[0]->d_name);
1306
fprintf(stderr, "Using interface \"%s\"\n", interface);
1308
if(interface == NULL){
1311
exitcode = EXIT_FAILURE;
1317
fprintf(stderr, "Could not find a network interface\n");
1318
exitcode = EXIT_FAILURE;
1022
1323
/* Initialize Avahi early so avahi_simple_poll_quit() can be called
1023
1324
from the signal handler */
1034
1335
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1036
1337
perror("sigaddset");
1037
exitcode = EXIT_FAILURE;
1338
exitcode = EX_OSERR;
1040
1341
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1042
1343
perror("sigaddset");
1043
exitcode = EXIT_FAILURE;
1344
exitcode = EX_OSERR;
1046
1347
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1048
1349
perror("sigaddset");
1049
exitcode = EXIT_FAILURE;
1052
ret = sigaction(SIGTERM, &sigterm_action, &old_sigterm_action);
1054
perror("sigaction");
1055
exitcode = EXIT_FAILURE;
1350
exitcode = EX_OSERR;
1353
/* Need to check if the handler is SIG_IGN before handling:
1354
| [[info:libc:Initial Signal Actions]] |
1355
| [[info:libc:Basic Signal Handling]] |
1357
ret = sigaction(SIGINT, NULL, &old_sigterm_action);
1359
perror("sigaction");
1362
if(old_sigterm_action.sa_handler != SIG_IGN){
1363
ret = sigaction(SIGINT, &sigterm_action, NULL);
1365
perror("sigaction");
1366
exitcode = EX_OSERR;
1370
ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
1372
perror("sigaction");
1375
if(old_sigterm_action.sa_handler != SIG_IGN){
1376
ret = sigaction(SIGHUP, &sigterm_action, NULL);
1378
perror("sigaction");
1379
exitcode = EX_OSERR;
1383
ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
1385
perror("sigaction");
1388
if(old_sigterm_action.sa_handler != SIG_IGN){
1389
ret = sigaction(SIGTERM, &sigterm_action, NULL);
1391
perror("sigaction");
1392
exitcode = EX_OSERR;
1059
1397
/* If the interface is down, bring it up */
1060
if(interface[0] != '\0'){
1398
if(strcmp(interface, "none") != 0){
1399
if_index = (AvahiIfIndex) if_nametoindex(interface);
1401
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1402
exitcode = EX_UNAVAILABLE;
1410
/* Re-raise priviliges */
1061
1417
#ifdef __linux__
1062
1418
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1063
messages to mess up the prompt */
1419
messages about the network interface to mess up the prompt */
1064
1420
ret = klogctl(8, NULL, 5);
1065
1421
bool restore_loglevel = true;
1097
1459
#endif /* __linux__ */
1098
exitcode = EXIT_FAILURE;
1460
exitcode = EX_OSERR;
1461
/* Lower privileges */
1101
1469
if((network.ifr_flags & IFF_UP) == 0){
1102
1470
network.ifr_flags |= IFF_UP;
1471
take_down_interface = true;
1103
1472
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1105
perror("ioctl SIOCSIFFLAGS");
1106
exitcode = EXIT_FAILURE;
1474
take_down_interface = false;
1475
perror("ioctl SIOCSIFFLAGS +IFF_UP");
1476
exitcode = EX_OSERR;
1107
1477
#ifdef __linux__
1108
1478
if(restore_loglevel){
1109
1479
ret = klogctl(7, NULL, 0);
1147
1523
#endif /* __linux__ */
1524
/* Lower privileges */
1526
if(take_down_interface){
1527
/* Lower privileges */
1533
/* Lower privileges permanently */
1164
1545
ret = init_gnutls_global(pubkey, seckey);
1166
1547
fprintf(stderr, "init_gnutls_global failed\n");
1167
exitcode = EXIT_FAILURE;
1548
exitcode = EX_UNAVAILABLE;
1170
1551
gnutls_initialized = true;
1558
tempdir_created = true;
1173
1559
if(mkdtemp(tempdir) == NULL){
1560
tempdir_created = false;
1174
1561
perror("mkdtemp");
1177
tempdir_created = true;
1179
1569
if(not init_gpgme(pubkey, seckey, tempdir)){
1180
1570
fprintf(stderr, "init_gpgme failed\n");
1181
exitcode = EXIT_FAILURE;
1571
exitcode = EX_UNAVAILABLE;
1184
1574
gpgme_initialized = true;
1187
if(interface[0] != '\0'){
1188
if_index = (AvahiIfIndex) if_nametoindex(interface);
1190
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1191
exitcode = EXIT_FAILURE;
1196
1581
if(connect_to != NULL){
1199
1584
char *address = strrchr(connect_to, ':');
1200
1585
if(address == NULL){
1201
1586
fprintf(stderr, "No colon in address\n");
1202
exitcode = EXIT_FAILURE;
1587
exitcode = EX_USAGE;
1207
1597
tmpmax = strtoimax(address+1, &tmp, 10);
1208
1598
if(errno != 0 or tmp == address+1 or *tmp != '\0'
1209
1599
or tmpmax != (uint16_t)tmpmax){
1210
1600
fprintf(stderr, "Bad port number\n");
1211
exitcode = EXIT_FAILURE;
1601
exitcode = EX_USAGE;
1214
1609
port = (uint16_t)tmpmax;
1215
1610
*address = '\0';
1216
1611
address = connect_to;
1224
ret = start_mandos_communication(address, port, if_index, af);
1226
exitcode = EXIT_FAILURE;
1624
while(not quit_now){
1625
ret = start_mandos_communication(address, port, if_index, af);
1626
if(quit_now or ret == 0){
1228
1633
exitcode = EXIT_SUCCESS;
1234
1644
AvahiServerConfig config;
1235
1645
/* Do not publish any local Zeroconf records */
1304
1722
/* Take down the network interface */
1305
if(interface_taken_up){
1306
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1723
if(take_down_interface){
1724
/* Re-raise priviliges */
1308
perror("ioctl SIOCGIFFLAGS");
1309
} else if(network.ifr_flags & IFF_UP) {
1310
network.ifr_flags &= ~IFF_UP; /* clear flag */
1311
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1313
perror("ioctl SIOCSIFFLAGS");
1316
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1731
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1733
perror("ioctl SIOCGIFFLAGS");
1734
} else if(network.ifr_flags & IFF_UP) {
1735
network.ifr_flags &= ~(short)IFF_UP; /* clear flag */
1736
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1738
perror("ioctl SIOCSIFFLAGS -IFF_UP");
1741
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1745
/* Lower privileges permanently */
1799
sigemptyset(&old_sigterm_action.sa_mask);
1800
old_sigterm_action.sa_handler = SIG_DFL;
1801
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
1802
&old_sigterm_action,
1805
perror("sigaction");
1808
ret = raise(signal_received);
1809
} while(ret != 0 and errno == EINTR);
1814
TEMP_FAILURE_RETRY(pause());
1366
1817
return exitcode;