32
32
/* Needed by GPGME, specifically gpgme_data_seek() */
33
#ifndef _LARGEFILE_SOURCE
34
33
#define _LARGEFILE_SOURCE
36
#ifndef _FILE_OFFSET_BITS
37
34
#define _FILE_OFFSET_BITS 64
40
36
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), asprintf() */
42
38
#include <stdio.h> /* fprintf(), stderr, fwrite(),
43
stdout, ferror(), remove() */
39
stdout, ferror(), sscanf(),
44
41
#include <stdint.h> /* uint16_t, uint32_t */
45
42
#include <stddef.h> /* NULL, size_t, ssize_t */
46
43
#include <stdlib.h> /* free(), EXIT_SUCCESS, EXIT_FAILURE,
48
45
#include <stdbool.h> /* bool, false, true */
49
46
#include <string.h> /* memset(), strcmp(), strlen(),
50
47
strerror(), asprintf(), strcpy() */
59
56
#include <fcntl.h> /* open() */
60
57
#include <dirent.h> /* opendir(), struct dirent, readdir()
62
#include <inttypes.h> /* PRIu16, PRIdMAX, intmax_t,
59
#include <inttypes.h> /* PRIu16, intmax_t, SCNdMAX */
64
60
#include <assert.h> /* assert() */
65
61
#include <errno.h> /* perror(), errno */
66
62
#include <time.h> /* nanosleep(), time() */
79
75
argp_state, struct argp,
80
76
argp_parse(), ARGP_KEY_ARG,
81
77
ARGP_KEY_END, ARGP_ERR_UNKNOWN */
82
#include <signal.h> /* sigemptyset(), sigaddset(),
83
sigaction(), SIGTERM, sig_atomic_t,
87
79
#include <sys/klog.h> /* klogctl() */
88
#endif /* __linux__ */
91
83
/* All Avahi types, constants and functions
138
130
} 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" };
146
* Make additional room in "buffer" for at least BUFFER_SIZE more
147
* bytes. "buffer_capacity" is how much is currently allocated,
133
* Make room in "buffer" for at least BUFFER_SIZE additional bytes.
134
* "buffer_capacity" is how much is currently allocated,
148
135
* "buffer_length" is how much is already used.
150
size_t incbuffer(char **buffer, size_t buffer_length,
137
size_t adjustbuffer(char **buffer, size_t buffer_length,
151
138
size_t buffer_capacity){
152
139
if(buffer_length + BUFFER_SIZE > buffer_capacity){
153
140
*buffer = realloc(*buffer, buffer_capacity + BUFFER_SIZE);
163
150
* Initialize GPGME.
165
static bool init_gpgme(const char *seckey,
152
static bool init_gpgme(mandos_context *mc, const char *seckey,
166
153
const char *pubkey, const char *tempdir){
168
155
gpgme_error_t rc;
192
rc = gpgme_op_import(mc.ctx, pgp_data);
179
rc = gpgme_op_import(mc->ctx, pgp_data);
193
180
if(rc != GPG_ERR_NO_ERROR){
194
181
fprintf(stderr, "bad gpgme_op_import: %s: %s\n",
195
182
gpgme_strsource(rc), gpgme_strerror(rc));
240
227
/* Create new GPGME "context" */
241
rc = gpgme_new(&(mc.ctx));
228
rc = gpgme_new(&(mc->ctx));
242
229
if(rc != GPG_ERR_NO_ERROR){
243
230
fprintf(stderr, "bad gpgme_new: %s: %s\n",
244
231
gpgme_strsource(rc), gpgme_strerror(rc));
256
243
* Decrypt OpenPGP data.
257
244
* Returns -1 on error
259
static ssize_t pgp_packet_decrypt(const char *cryptotext,
246
static ssize_t pgp_packet_decrypt(const mandos_context *mc,
247
const char *cryptotext,
260
248
size_t crypto_size,
261
249
char **plaintext){
262
250
gpgme_data_t dh_crypto, dh_plain;
290
278
/* Decrypt data from the cryptotext data buffer to the plaintext
292
rc = gpgme_op_decrypt(mc.ctx, dh_crypto, dh_plain);
280
rc = gpgme_op_decrypt(mc->ctx, dh_crypto, dh_plain);
293
281
if(rc != GPG_ERR_NO_ERROR){
294
282
fprintf(stderr, "bad gpgme_op_decrypt: %s: %s\n",
295
283
gpgme_strsource(rc), gpgme_strerror(rc));
296
284
plaintext_length = -1;
298
286
gpgme_decrypt_result_t result;
299
result = gpgme_op_decrypt_result(mc.ctx);
287
result = gpgme_op_decrypt_result(mc->ctx);
300
288
if(result == NULL){
301
289
fprintf(stderr, "gpgme_op_decrypt_result failed\n");
310
298
gpgme_recipient_t recipient;
311
299
recipient = result->recipients;
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;
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;
337
327
*plaintext = NULL;
339
plaintext_capacity = incbuffer(plaintext,
329
plaintext_capacity = adjustbuffer(plaintext,
340
330
(size_t)plaintext_length,
341
331
plaintext_capacity);
342
332
if(plaintext_capacity == 0){
333
perror("adjustbuffer");
344
334
plaintext_length = -1;
345
335
goto decrypt_end;
392
382
fprintf(stderr, "GnuTLS: %s", string);
395
static int init_gnutls_global(const char *pubkeyfilename,
385
static int init_gnutls_global(mandos_context *mc,
386
const char *pubkeyfilename,
396
387
const char *seckeyfilename){
418
409
/* OpenPGP credentials */
419
gnutls_certificate_allocate_credentials(&mc.cred);
410
gnutls_certificate_allocate_credentials(&mc->cred);
420
411
if(ret != GNUTLS_E_SUCCESS){
421
412
fprintf(stderr, "GnuTLS memory error: %s\n", /* Spurious warning
436
427
ret = gnutls_certificate_set_openpgp_key_file
437
(mc.cred, pubkeyfilename, seckeyfilename,
428
(mc->cred, pubkeyfilename, seckeyfilename,
438
429
GNUTLS_OPENPGP_FMT_BASE64);
439
430
if(ret != GNUTLS_E_SUCCESS){
448
439
/* GnuTLS server initialization */
449
ret = gnutls_dh_params_init(&mc.dh_params);
440
ret = gnutls_dh_params_init(&mc->dh_params);
450
441
if(ret != GNUTLS_E_SUCCESS){
451
442
fprintf(stderr, "Error in GnuTLS DH parameter initialization:"
452
443
" %s\n", safer_gnutls_strerror(ret));
455
ret = gnutls_dh_params_generate2(mc.dh_params, mc.dh_bits);
446
ret = gnutls_dh_params_generate2(mc->dh_params, mc->dh_bits);
456
447
if(ret != GNUTLS_E_SUCCESS){
457
448
fprintf(stderr, "Error in GnuTLS prime generation: %s\n",
458
449
safer_gnutls_strerror(ret));
462
gnutls_certificate_set_dh_params(mc.cred, mc.dh_params);
453
gnutls_certificate_set_dh_params(mc->cred, mc->dh_params);
468
gnutls_certificate_free_credentials(mc.cred);
459
gnutls_certificate_free_credentials(mc->cred);
469
460
gnutls_global_deinit();
470
gnutls_dh_params_deinit(mc.dh_params);
461
gnutls_dh_params_deinit(mc->dh_params);
474
static int init_gnutls_session(gnutls_session_t *session){
465
static int init_gnutls_session(mandos_context *mc,
466
gnutls_session_t *session){
476
468
/* GnuTLS session creation */
477
469
ret = gnutls_init(session, GNUTLS_SERVER);
485
ret = gnutls_priority_set_direct(*session, mc.priority, &err);
477
ret = gnutls_priority_set_direct(*session, mc->priority, &err);
486
478
if(ret != GNUTLS_E_SUCCESS){
487
479
fprintf(stderr, "Syntax error at: %s\n", err);
488
480
fprintf(stderr, "GnuTLS error: %s\n",
495
487
ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,
497
489
if(ret != GNUTLS_E_SUCCESS){
498
490
fprintf(stderr, "Error setting GnuTLS credentials: %s\n",
499
491
safer_gnutls_strerror(ret));
505
497
gnutls_certificate_server_set_request(*session,
506
498
GNUTLS_CERT_IGNORE);
508
gnutls_dh_set_prime_bits(*session, mc.dh_bits);
500
gnutls_dh_set_prime_bits(*session, mc->dh_bits);
514
506
static void empty_log(__attribute__((unused)) AvahiLogLevel level,
515
507
__attribute__((unused)) const char *txt){}
517
sig_atomic_t quit_now = 0;
518
int signal_received = 0;
520
509
/* Called when a Mandos server is found */
521
510
static int start_mandos_communication(const char *ip, uint16_t port,
522
511
AvahiIfIndex if_index,
512
mandos_context *mc, int af){
568
557
memset(&to, 0, sizeof(to));
569
558
if(af == AF_INET6){
570
to.in6.sin6_family = (sa_family_t)af;
559
to.in6.sin6_family = (uint16_t)af;
571
560
ret = inet_pton(af, ip, &to.in6.sin6_addr);
572
561
} else { /* IPv4 */
573
562
to.in.sin_family = (sa_family_t)af;
699
buffer_capacity = incbuffer(&buffer, buffer_length,
688
buffer_capacity = adjustbuffer(&buffer, buffer_length,
700
689
buffer_capacity);
701
690
if(buffer_capacity == 0){
691
perror("adjustbuffer");
744
733
gnutls_bye(session, GNUTLS_SHUT_RDWR);
746
735
if(buffer_length > 0){
747
decrypted_buffer_size = pgp_packet_decrypt(buffer,
736
decrypted_buffer_size = pgp_packet_decrypt(mc, buffer,
749
738
&decrypted_buffer);
750
739
if(decrypted_buffer_size >= 0){
796
785
AVAHI_GCC_UNUSED AvahiStringList *txt,
797
786
AVAHI_GCC_UNUSED AvahiLookupResultFlags
799
AVAHI_GCC_UNUSED void* userdata){
789
mandos_context *mc = userdata;
802
792
/* Called whenever a service has been resolved successfully or
811
797
case AVAHI_RESOLVER_FAILURE:
812
798
fprintf(stderr, "(Avahi Resolver) Failed to resolve service '%s'"
813
799
" of type '%s' in domain '%s': %s\n", name, type, domain,
814
avahi_strerror(avahi_server_errno(mc.server)));
800
avahi_strerror(avahi_server_errno(mc->server)));
817
803
case AVAHI_RESOLVER_FOUND:
823
809
PRIdMAX ") on port %" PRIu16 "\n", name, host_name,
824
810
ip, (intmax_t)interface, port);
826
int ret = start_mandos_communication(ip, port, interface,
812
int ret = start_mandos_communication(ip, port, interface, mc,
827
813
avahi_proto_to_af(proto));
829
avahi_simple_poll_quit(mc.simple_poll);
815
avahi_simple_poll_quit(mc->simple_poll);
853
840
case AVAHI_BROWSER_FAILURE:
855
842
fprintf(stderr, "(Avahi browser) %s\n",
856
avahi_strerror(avahi_server_errno(mc.server)));
857
avahi_simple_poll_quit(mc.simple_poll);
843
avahi_strerror(avahi_server_errno(mc->server)));
844
avahi_simple_poll_quit(mc->simple_poll);
860
847
case AVAHI_BROWSER_NEW:
863
850
the callback function is called the Avahi server will free the
864
851
resolver for us. */
866
if(avahi_s_service_resolver_new(mc.server, interface, protocol,
867
name, type, domain, protocol, 0,
868
resolve_callback, NULL) == NULL)
853
if(!(avahi_s_service_resolver_new(mc->server, interface,
854
protocol, name, type, domain,
855
AVAHI_PROTO_INET6, 0,
856
resolve_callback, mc)))
869
857
fprintf(stderr, "Avahi: Failed to resolve service '%s': %s\n",
870
name, avahi_strerror(avahi_server_errno(mc.server)));
858
name, avahi_strerror(avahi_server_errno(mc->server)));
873
861
case AVAHI_BROWSER_REMOVE:
885
/* stop main loop after sigterm has been called */
886
static void handle_sigterm(int sig){
891
signal_received = sig;
892
int old_errno = errno;
893
if(mc.simple_poll != NULL){
894
avahi_simple_poll_quit(mc.simple_poll);
899
873
int main(int argc, char *argv[]){
900
874
AvahiSServiceBrowser *sb = NULL;
905
879
int exitcode = EXIT_SUCCESS;
906
880
const char *interface = "eth0";
907
881
struct ifreq network;
909
bool take_down_interface = false;
912
885
char *connect_to = NULL;
916
889
const char *seckey = PATHDIR "/" SECKEY;
917
890
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" };
919
895
bool gnutls_initialized = false;
920
896
bool gpgme_initialized = false;
923
struct sigaction old_sigterm_action;
924
struct sigaction sigterm_action = { .sa_handler = handle_sigterm };
927
900
struct argp_option options[] = {
981
954
case 129: /* --dh-bits */
983
tmpmax = strtoimax(arg, &tmp, 10);
984
if(errno != 0 or tmp == arg or *tmp != '\0'
985
or tmpmax != (typeof(mc.dh_bits))tmpmax){
955
ret = sscanf(arg, "%" SCNdMAX "%n", &tmpmax, &numchars);
956
if(ret < 1 or tmpmax != (typeof(mc.dh_bits))tmpmax
957
or arg[numchars] != '\0'){
986
958
fprintf(stderr, "Bad number of DH bits\n");
987
959
exit(EXIT_FAILURE);
992
964
mc.priority = arg;
994
966
case 131: /* --delay */
996
delay = strtof(arg, &tmp);
997
if(errno != 0 or tmp == arg or *tmp != '\0'){
967
ret = sscanf(arg, "%lf%n", &delay, &numchars);
968
if(ret < 1 or arg[numchars] != '\0'){
998
969
fprintf(stderr, "Bad delay\n");
999
970
exit(EXIT_FAILURE);
1025
avahi_set_log_function(empty_log);
1028
/* Initialize Avahi early so avahi_simple_poll_quit() can be called
1029
from the signal handler */
1030
/* Initialize the pseudo-RNG for Avahi */
1031
srand((unsigned int) time(NULL));
1032
mc.simple_poll = avahi_simple_poll_new();
1033
if(mc.simple_poll == NULL){
1034
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1035
exitcode = EXIT_FAILURE;
1039
sigemptyset(&sigterm_action.sa_mask);
1040
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1042
perror("sigaddset");
1043
exitcode = EXIT_FAILURE;
1046
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1048
perror("sigaddset");
1049
exitcode = EXIT_FAILURE;
1052
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1054
perror("sigaddset");
1055
exitcode = EXIT_FAILURE;
1058
ret = sigaction(SIGINT, &sigterm_action, &old_sigterm_action);
1060
perror("sigaction");
1061
exitcode = EXIT_FAILURE;
1064
ret = sigaction(SIGHUP, &sigterm_action, NULL);
1066
perror("sigaction");
1067
exitcode = EXIT_FAILURE;
1070
ret = sigaction(SIGTERM, &sigterm_action, NULL);
1072
perror("sigaction");
1073
exitcode = EXIT_FAILURE;
1077
995
/* If the interface is down, bring it up */
1078
996
if(interface[0] != '\0'){
1079
if_index = (AvahiIfIndex) if_nametoindex(interface);
1081
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1082
exitcode = EXIT_FAILURE;
1090
997
#ifdef __linux__
1091
998
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1092
999
messages to mess up the prompt */
1123
1030
perror("klogctl");
1126
#endif /* __linux__ */
1127
1034
exitcode = EXIT_FAILURE;
1130
1037
if((network.ifr_flags & IFF_UP) == 0){
1131
1038
network.ifr_flags |= IFF_UP;
1132
take_down_interface = true;
1133
1039
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1135
take_down_interface = false;
1136
1041
perror("ioctl SIOCSIFFLAGS");
1137
1042
exitcode = EXIT_FAILURE;
1138
1043
#ifdef __linux__
1196
1094
perror("setuid");
1203
ret = init_gnutls_global(pubkey, seckey);
1097
ret = init_gnutls_global(&mc, pubkey, seckey);
1205
1099
fprintf(stderr, "init_gnutls_global failed\n");
1206
1100
exitcode = EXIT_FAILURE;
1209
1103
gnutls_initialized = true;
1216
tempdir_created = true;
1217
1106
if(mkdtemp(tempdir) == NULL){
1218
tempdir_created = false;
1219
1107
perror("mkdtemp");
1227
if(not init_gpgme(pubkey, seckey, tempdir)){
1110
tempdir_created = true;
1112
if(not init_gpgme(&mc, pubkey, seckey, tempdir)){
1228
1113
fprintf(stderr, "init_gpgme failed\n");
1229
1114
exitcode = EXIT_FAILURE;
1232
1117
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;
1239
1129
if(connect_to != NULL){
1245
1135
exitcode = EXIT_FAILURE;
1255
tmpmax = strtoimax(address+1, &tmp, 10);
1256
if(errno != 0 or tmp == address+1 or *tmp != '\0'
1257
or tmpmax != (uint16_t)tmpmax){
1139
ret = sscanf(address+1, "%" SCNdMAX "%n", &tmpmax, &numchars);
1140
if(ret < 1 or tmpmax != (uint16_t)tmpmax
1141
or address[numchars+1] != '\0'){
1258
1142
fprintf(stderr, "Bad port number\n");
1259
1143
exitcode = EXIT_FAILURE;
1267
1146
port = (uint16_t)tmpmax;
1268
1147
*address = '\0';
1269
1148
address = connect_to;
1282
ret = start_mandos_communication(address, port, if_index, af);
1156
ret = start_mandos_communication(address, port, if_index, &mc,
1284
1159
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;
1325
1207
/* Create the Avahi service browser */
1326
1208
sb = avahi_s_service_browser_new(mc.server, if_index,
1327
AVAHI_PROTO_UNSPEC, "_mandos._tcp",
1328
NULL, 0, browse_callback, NULL);
1209
AVAHI_PROTO_INET6, "_mandos._tcp",
1210
NULL, 0, browse_callback, &mc);
1329
1211
if(sb == NULL){
1330
1212
fprintf(stderr, "Failed to create service browser: %s\n",
1331
1213
avahi_strerror(avahi_server_errno(mc.server)));
1371
1249
gpgme_release(mc.ctx);
1374
/* Take down the network interface */
1375
if(take_down_interface){
1376
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1378
perror("ioctl SIOCGIFFLAGS");
1379
} else if(network.ifr_flags & IFF_UP) {
1380
network.ifr_flags &= ~IFF_UP; /* clear flag */
1381
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1383
perror("ioctl SIOCSIFFLAGS");
1386
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1392
1252
/* Removes the temp directory used by GPGME */
1393
1253
if(tempdir_created){