32
32
/* Needed by GPGME, specifically gpgme_data_seek() */
33
#ifndef _LARGEFILE_SOURCE
33
34
#define _LARGEFILE_SOURCE
36
#ifndef _FILE_OFFSET_BITS
34
37
#define _FILE_OFFSET_BITS 64
36
40
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), asprintf() */
38
42
#include <stdio.h> /* fprintf(), stderr, fwrite(),
39
stdout, ferror(), sscanf(),
43
stdout, ferror(), remove() */
41
44
#include <stdint.h> /* uint16_t, uint32_t */
42
45
#include <stddef.h> /* NULL, size_t, ssize_t */
43
46
#include <stdlib.h> /* free(), EXIT_SUCCESS, EXIT_FAILURE,
45
48
#include <stdbool.h> /* bool, false, true */
46
49
#include <string.h> /* memset(), strcmp(), strlen(),
47
50
strerror(), asprintf(), strcpy() */
56
59
#include <fcntl.h> /* open() */
57
60
#include <dirent.h> /* opendir(), struct dirent, readdir()
59
#include <inttypes.h> /* PRIu16, intmax_t, SCNdMAX */
62
#include <inttypes.h> /* PRIu16, PRIdMAX, intmax_t,
60
64
#include <assert.h> /* assert() */
61
65
#include <errno.h> /* perror(), errno */
62
66
#include <time.h> /* nanosleep(), time() */
75
79
argp_state, struct argp,
76
80
argp_parse(), ARGP_KEY_ARG,
77
81
ARGP_KEY_END, ARGP_ERR_UNKNOWN */
82
#include <signal.h> /* sigemptyset(), sigaddset(),
83
sigaction(), SIGTERM, sig_atomic_t,
79
87
#include <sys/klog.h> /* klogctl() */
88
#endif /* __linux__ */
83
91
/* All Avahi types, constants and functions
130
138
} mandos_context;
140
/* global context so signal handler can reach it*/
141
mandos_context mc = { .simple_poll = NULL, .server = NULL,
142
.dh_bits = 1024, .priority = "SECURE256"
143
":!CTYPE-X.509:+CTYPE-OPENPGP" };
133
* Make room in "buffer" for at least BUFFER_SIZE additional bytes.
134
* "buffer_capacity" is how much is currently allocated,
146
* Make additional room in "buffer" for at least BUFFER_SIZE more
147
* bytes. "buffer_capacity" is how much is currently allocated,
135
148
* "buffer_length" is how much is already used.
137
size_t adjustbuffer(char **buffer, size_t buffer_length,
150
size_t incbuffer(char **buffer, size_t buffer_length,
138
151
size_t buffer_capacity){
139
152
if(buffer_length + BUFFER_SIZE > buffer_capacity){
140
153
*buffer = realloc(*buffer, buffer_capacity + BUFFER_SIZE);
150
163
* Initialize GPGME.
152
static bool init_gpgme(mandos_context *mc, const char *seckey,
165
static bool init_gpgme(const char *seckey,
153
166
const char *pubkey, const char *tempdir){
155
168
gpgme_error_t rc;
179
rc = gpgme_op_import(mc->ctx, pgp_data);
192
rc = gpgme_op_import(mc.ctx, pgp_data);
180
193
if(rc != GPG_ERR_NO_ERROR){
181
194
fprintf(stderr, "bad gpgme_op_import: %s: %s\n",
182
195
gpgme_strsource(rc), gpgme_strerror(rc));
227
240
/* Create new GPGME "context" */
228
rc = gpgme_new(&(mc->ctx));
241
rc = gpgme_new(&(mc.ctx));
229
242
if(rc != GPG_ERR_NO_ERROR){
230
243
fprintf(stderr, "bad gpgme_new: %s: %s\n",
231
244
gpgme_strsource(rc), gpgme_strerror(rc));
278
290
/* Decrypt data from the cryptotext data buffer to the plaintext
280
rc = gpgme_op_decrypt(mc->ctx, dh_crypto, dh_plain);
292
rc = gpgme_op_decrypt(mc.ctx, dh_crypto, dh_plain);
281
293
if(rc != GPG_ERR_NO_ERROR){
282
294
fprintf(stderr, "bad gpgme_op_decrypt: %s: %s\n",
283
295
gpgme_strsource(rc), gpgme_strerror(rc));
284
296
plaintext_length = -1;
286
298
gpgme_decrypt_result_t result;
287
result = gpgme_op_decrypt_result(mc->ctx);
299
result = gpgme_op_decrypt_result(mc.ctx);
288
300
if(result == NULL){
289
301
fprintf(stderr, "gpgme_op_decrypt_result failed\n");
298
310
gpgme_recipient_t recipient;
299
311
recipient = result->recipients;
301
while(recipient != NULL){
302
fprintf(stderr, "Public key algorithm: %s\n",
303
gpgme_pubkey_algo_name(recipient->pubkey_algo));
304
fprintf(stderr, "Key ID: %s\n", recipient->keyid);
305
fprintf(stderr, "Secret key available: %s\n",
306
recipient->status == GPG_ERR_NO_SECKEY
308
recipient = recipient->next;
312
while(recipient != NULL){
313
fprintf(stderr, "Public key algorithm: %s\n",
314
gpgme_pubkey_algo_name(recipient->pubkey_algo));
315
fprintf(stderr, "Key ID: %s\n", recipient->keyid);
316
fprintf(stderr, "Secret key available: %s\n",
317
recipient->status == GPG_ERR_NO_SECKEY
319
recipient = recipient->next;
327
337
*plaintext = NULL;
329
plaintext_capacity = adjustbuffer(plaintext,
339
plaintext_capacity = incbuffer(plaintext,
330
340
(size_t)plaintext_length,
331
341
plaintext_capacity);
332
342
if(plaintext_capacity == 0){
333
perror("adjustbuffer");
334
344
plaintext_length = -1;
335
345
goto decrypt_end;
382
392
fprintf(stderr, "GnuTLS: %s", string);
385
static int init_gnutls_global(mandos_context *mc,
386
const char *pubkeyfilename,
395
static int init_gnutls_global(const char *pubkeyfilename,
387
396
const char *seckeyfilename){
409
418
/* OpenPGP credentials */
410
gnutls_certificate_allocate_credentials(&mc->cred);
419
gnutls_certificate_allocate_credentials(&mc.cred);
411
420
if(ret != GNUTLS_E_SUCCESS){
412
421
fprintf(stderr, "GnuTLS memory error: %s\n", /* Spurious warning
427
436
ret = gnutls_certificate_set_openpgp_key_file
428
(mc->cred, pubkeyfilename, seckeyfilename,
437
(mc.cred, pubkeyfilename, seckeyfilename,
429
438
GNUTLS_OPENPGP_FMT_BASE64);
430
439
if(ret != GNUTLS_E_SUCCESS){
439
448
/* GnuTLS server initialization */
440
ret = gnutls_dh_params_init(&mc->dh_params);
449
ret = gnutls_dh_params_init(&mc.dh_params);
441
450
if(ret != GNUTLS_E_SUCCESS){
442
451
fprintf(stderr, "Error in GnuTLS DH parameter initialization:"
443
452
" %s\n", safer_gnutls_strerror(ret));
446
ret = gnutls_dh_params_generate2(mc->dh_params, mc->dh_bits);
455
ret = gnutls_dh_params_generate2(mc.dh_params, mc.dh_bits);
447
456
if(ret != GNUTLS_E_SUCCESS){
448
457
fprintf(stderr, "Error in GnuTLS prime generation: %s\n",
449
458
safer_gnutls_strerror(ret));
453
gnutls_certificate_set_dh_params(mc->cred, mc->dh_params);
462
gnutls_certificate_set_dh_params(mc.cred, mc.dh_params);
459
gnutls_certificate_free_credentials(mc->cred);
468
gnutls_certificate_free_credentials(mc.cred);
460
469
gnutls_global_deinit();
461
gnutls_dh_params_deinit(mc->dh_params);
470
gnutls_dh_params_deinit(mc.dh_params);
465
static int init_gnutls_session(mandos_context *mc,
466
gnutls_session_t *session){
474
static int init_gnutls_session(gnutls_session_t *session){
468
476
/* GnuTLS session creation */
469
477
ret = gnutls_init(session, GNUTLS_SERVER);
477
ret = gnutls_priority_set_direct(*session, mc->priority, &err);
485
ret = gnutls_priority_set_direct(*session, mc.priority, &err);
478
486
if(ret != GNUTLS_E_SUCCESS){
479
487
fprintf(stderr, "Syntax error at: %s\n", err);
480
488
fprintf(stderr, "GnuTLS error: %s\n",
487
495
ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,
489
497
if(ret != GNUTLS_E_SUCCESS){
490
498
fprintf(stderr, "Error setting GnuTLS credentials: %s\n",
491
499
safer_gnutls_strerror(ret));
506
514
static void empty_log(__attribute__((unused)) AvahiLogLevel level,
507
515
__attribute__((unused)) const char *txt){}
517
sig_atomic_t quit_now = 0;
518
int signal_received = 0;
509
520
/* Called when a Mandos server is found */
510
521
static int start_mandos_communication(const char *ip, uint16_t port,
511
522
AvahiIfIndex if_index,
512
mandos_context *mc, int af){
524
int ret, tcp_sd = -1;
516
527
struct sockaddr_in in;
551
566
tcp_sd = socket(pf, SOCK_STREAM, 0);
553
568
perror("socket");
557
577
memset(&to, 0, sizeof(to));
558
578
if(af == AF_INET6){
559
to.in6.sin6_family = (uint16_t)af;
579
to.in6.sin6_family = (sa_family_t)af;
560
580
ret = inet_pton(af, ip, &to.in6.sin6_addr);
561
581
} else { /* IPv4 */
562
582
to.in.sin_family = (sa_family_t)af;
581
603
if(if_index == AVAHI_IF_UNSPEC){
582
604
fprintf(stderr, "An IPv6 link-local address is incomplete"
583
605
" without a network interface\n");
586
609
/* Set the network interface number as scope */
587
610
to.in6.sin6_scope_id = (uint32_t)if_index;
662
702
fprintf(stderr, "Establishing TLS session with %s\n", ip);
665
709
gnutls_transport_set_ptr(session, (gnutls_transport_ptr_t) tcp_sd);
668
716
ret = gnutls_handshake(session);
669
720
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
671
722
if(ret != GNUTLS_E_SUCCESS){
688
buffer_capacity = adjustbuffer(&buffer, buffer_length,
744
buffer_capacity = incbuffer(&buffer, buffer_length,
689
745
buffer_capacity);
690
746
if(buffer_capacity == 0){
691
perror("adjustbuffer");
696
756
sret = gnutls_record_recv(session, buffer+buffer_length,
706
766
case GNUTLS_E_REHANDSHAKE:
708
768
ret = gnutls_handshake(session);
709
773
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
711
775
fprintf(stderr, "*** GnuTLS Re-handshake failed ***\n");
730
794
fprintf(stderr, "Closing TLS session\n");
733
801
gnutls_bye(session, GNUTLS_SHUT_RDWR);
735
807
if(buffer_length > 0){
736
decrypted_buffer_size = pgp_packet_decrypt(mc, buffer,
808
decrypted_buffer_size = pgp_packet_decrypt(buffer,
738
810
&decrypted_buffer);
739
811
if(decrypted_buffer_size >= 0){
741
813
while(written < (size_t) decrypted_buffer_size){
742
818
ret = (int)fwrite(decrypted_buffer + written, 1,
743
819
(size_t)decrypted_buffer_size - written,
785
866
AVAHI_GCC_UNUSED AvahiStringList *txt,
786
867
AVAHI_GCC_UNUSED AvahiLookupResultFlags
789
mandos_context *mc = userdata;
869
AVAHI_GCC_UNUSED void* userdata){
792
872
/* Called whenever a service has been resolved successfully or
797
881
case AVAHI_RESOLVER_FAILURE:
798
882
fprintf(stderr, "(Avahi Resolver) Failed to resolve service '%s'"
799
883
" of type '%s' in domain '%s': %s\n", name, type, domain,
800
avahi_strerror(avahi_server_errno(mc->server)));
884
avahi_strerror(avahi_server_errno(mc.server)));
803
887
case AVAHI_RESOLVER_FOUND:
809
893
PRIdMAX ") on port %" PRIu16 "\n", name, host_name,
810
894
ip, (intmax_t)interface, port);
812
int ret = start_mandos_communication(ip, port, interface, mc,
896
int ret = start_mandos_communication(ip, port, interface,
813
897
avahi_proto_to_af(proto));
815
avahi_simple_poll_quit(mc->simple_poll);
899
avahi_simple_poll_quit(mc.simple_poll);
828
912
const char *domain,
829
913
AVAHI_GCC_UNUSED AvahiLookupResultFlags
832
mandos_context *mc = userdata;
915
AVAHI_GCC_UNUSED void* userdata){
835
918
/* Called whenever a new services becomes available on the LAN or
836
919
is removed from the LAN */
840
927
case AVAHI_BROWSER_FAILURE:
842
929
fprintf(stderr, "(Avahi browser) %s\n",
843
avahi_strerror(avahi_server_errno(mc->server)));
844
avahi_simple_poll_quit(mc->simple_poll);
930
avahi_strerror(avahi_server_errno(mc.server)));
931
avahi_simple_poll_quit(mc.simple_poll);
847
934
case AVAHI_BROWSER_NEW:
850
937
the callback function is called the Avahi server will free the
851
938
resolver for us. */
853
if(!(avahi_s_service_resolver_new(mc->server, interface,
854
protocol, name, type, domain,
855
AVAHI_PROTO_INET6, 0,
856
resolve_callback, mc)))
940
if(avahi_s_service_resolver_new(mc.server, interface, protocol,
941
name, type, domain, protocol, 0,
942
resolve_callback, NULL) == NULL)
857
943
fprintf(stderr, "Avahi: Failed to resolve service '%s': %s\n",
858
name, avahi_strerror(avahi_server_errno(mc->server)));
944
name, avahi_strerror(avahi_server_errno(mc.server)));
861
947
case AVAHI_BROWSER_REMOVE:
959
/* stop main loop after sigterm has been called */
960
static void handle_sigterm(int sig){
965
signal_received = sig;
966
int old_errno = errno;
967
if(mc.simple_poll != NULL){
968
avahi_simple_poll_quit(mc.simple_poll);
873
973
int main(int argc, char *argv[]){
874
974
AvahiSServiceBrowser *sb = NULL;
879
979
int exitcode = EXIT_SUCCESS;
880
980
const char *interface = "eth0";
881
981
struct ifreq network;
983
bool take_down_interface = false;
885
986
char *connect_to = NULL;
889
990
const char *seckey = PATHDIR "/" SECKEY;
890
991
const char *pubkey = PATHDIR "/" PUBKEY;
892
mandos_context mc = { .simple_poll = NULL, .server = NULL,
893
.dh_bits = 1024, .priority = "SECURE256"
894
":!CTYPE-X.509:+CTYPE-OPENPGP" };
895
993
bool gnutls_initialized = false;
896
994
bool gpgme_initialized = false;
997
struct sigaction old_sigterm_action;
998
struct sigaction sigterm_action = { .sa_handler = handle_sigterm };
900
1001
struct argp_option options[] = {
954
1055
case 129: /* --dh-bits */
955
ret = sscanf(arg, "%" SCNdMAX "%n", &tmpmax, &numchars);
956
if(ret < 1 or tmpmax != (typeof(mc.dh_bits))tmpmax
957
or arg[numchars] != '\0'){
1057
tmpmax = strtoimax(arg, &tmp, 10);
1058
if(errno != 0 or tmp == arg or *tmp != '\0'
1059
or tmpmax != (typeof(mc.dh_bits))tmpmax){
958
1060
fprintf(stderr, "Bad number of DH bits\n");
959
1061
exit(EXIT_FAILURE);
964
1066
mc.priority = arg;
966
1068
case 131: /* --delay */
967
ret = sscanf(arg, "%lf%n", &delay, &numchars);
968
if(ret < 1 or arg[numchars] != '\0'){
1070
delay = strtof(arg, &tmp);
1071
if(errno != 0 or tmp == arg or *tmp != '\0'){
969
1072
fprintf(stderr, "Bad delay\n");
970
1073
exit(EXIT_FAILURE);
1099
avahi_set_log_function(empty_log);
1102
/* Initialize Avahi early so avahi_simple_poll_quit() can be called
1103
from the signal handler */
1104
/* Initialize the pseudo-RNG for Avahi */
1105
srand((unsigned int) time(NULL));
1106
mc.simple_poll = avahi_simple_poll_new();
1107
if(mc.simple_poll == NULL){
1108
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1109
exitcode = EXIT_FAILURE;
1113
sigemptyset(&sigterm_action.sa_mask);
1114
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1116
perror("sigaddset");
1117
exitcode = EXIT_FAILURE;
1120
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1122
perror("sigaddset");
1123
exitcode = EXIT_FAILURE;
1126
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1128
perror("sigaddset");
1129
exitcode = EXIT_FAILURE;
1132
/* Need to check if the handler is SIG_IGN before handling:
1133
| [[info:libc:Initial Signal Actions]] |
1134
| [[info:libc:Basic Signal Handling]] |
1136
ret = sigaction(SIGINT, NULL, &old_sigterm_action);
1138
perror("sigaction");
1139
return EXIT_FAILURE;
1141
if(old_sigterm_action.sa_handler != SIG_IGN){
1142
ret = sigaction(SIGINT, &sigterm_action, NULL);
1144
perror("sigaction");
1145
exitcode = EXIT_FAILURE;
1149
ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
1151
perror("sigaction");
1152
return EXIT_FAILURE;
1154
if(old_sigterm_action.sa_handler != SIG_IGN){
1155
ret = sigaction(SIGHUP, &sigterm_action, NULL);
1157
perror("sigaction");
1158
exitcode = EXIT_FAILURE;
1162
ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
1164
perror("sigaction");
1165
return EXIT_FAILURE;
1167
if(old_sigterm_action.sa_handler != SIG_IGN){
1168
ret = sigaction(SIGTERM, &sigterm_action, NULL);
1170
perror("sigaction");
1171
exitcode = EXIT_FAILURE;
995
1176
/* If the interface is down, bring it up */
996
1177
if(interface[0] != '\0'){
1178
if_index = (AvahiIfIndex) if_nametoindex(interface);
1180
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1181
exitcode = EXIT_FAILURE;
997
1189
#ifdef __linux__
998
1190
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
999
1191
messages to mess up the prompt */
1030
1222
perror("klogctl");
1225
#endif /* __linux__ */
1034
1226
exitcode = EXIT_FAILURE;
1037
1229
if((network.ifr_flags & IFF_UP) == 0){
1038
1230
network.ifr_flags |= IFF_UP;
1231
take_down_interface = true;
1039
1232
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1234
take_down_interface = false;
1041
1235
perror("ioctl SIOCSIFFLAGS");
1042
1236
exitcode = EXIT_FAILURE;
1043
1237
#ifdef __linux__
1094
1295
perror("setuid");
1097
ret = init_gnutls_global(&mc, pubkey, seckey);
1302
ret = init_gnutls_global(pubkey, seckey);
1099
1304
fprintf(stderr, "init_gnutls_global failed\n");
1100
1305
exitcode = EXIT_FAILURE;
1103
1308
gnutls_initialized = true;
1315
tempdir_created = true;
1106
1316
if(mkdtemp(tempdir) == NULL){
1317
tempdir_created = false;
1107
1318
perror("mkdtemp");
1110
tempdir_created = true;
1112
if(not init_gpgme(&mc, pubkey, seckey, tempdir)){
1326
if(not init_gpgme(pubkey, seckey, tempdir)){
1113
1327
fprintf(stderr, "init_gpgme failed\n");
1114
1328
exitcode = EXIT_FAILURE;
1117
1331
gpgme_initialized = true;
1120
if(interface[0] != '\0'){
1121
if_index = (AvahiIfIndex) if_nametoindex(interface);
1123
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1124
exitcode = EXIT_FAILURE;
1129
1338
if(connect_to != NULL){
1135
1344
exitcode = EXIT_FAILURE;
1139
ret = sscanf(address+1, "%" SCNdMAX "%n", &tmpmax, &numchars);
1140
if(ret < 1 or tmpmax != (uint16_t)tmpmax
1141
or address[numchars+1] != '\0'){
1354
tmpmax = strtoimax(address+1, &tmp, 10);
1355
if(errno != 0 or tmp == address+1 or *tmp != '\0'
1356
or tmpmax != (uint16_t)tmpmax){
1142
1357
fprintf(stderr, "Bad port number\n");
1143
1358
exitcode = EXIT_FAILURE;
1146
1366
port = (uint16_t)tmpmax;
1147
1367
*address = '\0';
1148
1368
address = connect_to;
1156
ret = start_mandos_communication(address, port, if_index, &mc,
1381
ret = start_mandos_communication(address, port, if_index, af);
1159
1383
exitcode = EXIT_FAILURE;
1167
avahi_set_log_function(empty_log);
1170
/* Initialize the pseudo-RNG for Avahi */
1171
srand((unsigned int) time(NULL));
1173
/* Allocate main Avahi loop object */
1174
mc.simple_poll = avahi_simple_poll_new();
1175
if(mc.simple_poll == NULL){
1176
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1177
exitcode = EXIT_FAILURE;
1207
1424
/* Create the Avahi service browser */
1208
1425
sb = avahi_s_service_browser_new(mc.server, if_index,
1209
AVAHI_PROTO_INET6, "_mandos._tcp",
1210
NULL, 0, browse_callback, &mc);
1426
AVAHI_PROTO_UNSPEC, "_mandos._tcp",
1427
NULL, 0, browse_callback, NULL);
1211
1428
if(sb == NULL){
1212
1429
fprintf(stderr, "Failed to create service browser: %s\n",
1213
1430
avahi_strerror(avahi_server_errno(mc.server)));
1249
1470
gpgme_release(mc.ctx);
1473
/* Take down the network interface */
1474
if(take_down_interface){
1475
ret = ioctl(sd, SIOCGIFFLAGS, &network);
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));
1252
1491
/* Removes the temp directory used by GPGME */
1253
1492
if(tempdir_created){