42
42
#include <stddef.h> /* NULL, size_t, ssize_t */
43
43
#include <stdlib.h> /* free(), EXIT_SUCCESS, EXIT_FAILURE,
45
#include <stdbool.h> /* bool, true */
45
#include <stdbool.h> /* bool, false, true */
46
46
#include <string.h> /* memset(), strcmp(), strlen(),
47
47
strerror(), asprintf(), strcpy() */
48
#include <sys/ioctl.h> /* ioctl */
48
#include <sys/ioctl.h> /* ioctl */
49
49
#include <sys/types.h> /* socket(), inet_pton(), sockaddr,
50
50
sockaddr_in6, PF_INET6,
51
SOCK_STREAM, INET6_ADDRSTRLEN,
52
uid_t, gid_t, open(), opendir(),
51
SOCK_STREAM, uid_t, gid_t, open(),
54
53
#include <sys/stat.h> /* open() */
55
54
#include <sys/socket.h> /* socket(), struct sockaddr_in6,
56
struct in6_addr, inet_pton(),
55
inet_pton(), connect() */
58
56
#include <fcntl.h> /* open() */
59
57
#include <dirent.h> /* opendir(), struct dirent, readdir()
65
63
#include <net/if.h> /* ioctl, ifreq, SIOCGIFFLAGS, IFF_UP,
66
64
SIOCSIFFLAGS, if_indextoname(),
67
65
if_nametoindex(), IF_NAMESIZE */
68
#include <netinet/in.h>
66
#include <netinet/in.h> /* IN6_IS_ADDR_LINKLOCAL,
67
INET_ADDRSTRLEN, INET6_ADDRSTRLEN
69
69
#include <unistd.h> /* close(), SEEK_SET, off_t, write(),
70
70
getuid(), getgid(), setuid(),
72
72
#include <arpa/inet.h> /* inet_pton(), htons */
73
#include <iso646.h> /* not, and, or */
73
#include <iso646.h> /* not, or, and */
74
74
#include <argp.h> /* struct argp_option, error_t, struct
75
75
argp_state, struct argp,
76
76
argp_parse(), ARGP_KEY_ARG,
77
77
ARGP_KEY_END, ARGP_ERR_UNKNOWN */
78
#include <signal.h> /* sigemptyset(), sigaddset(),
79
sigaction(), SIGTERM, sigaction,
79
83
#include <sys/klog.h> /* klogctl() */
84
#endif /* __linux__ */
83
87
/* All Avahi types, constants and functions
130
134
} mandos_context;
136
/* global context so signal handler can reach it*/
137
mandos_context mc = { .simple_poll = NULL, .server = NULL,
138
.dh_bits = 1024, .priority = "SECURE256"
139
":!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,
142
* Make additional room in "buffer" for at least BUFFER_SIZE more
143
* bytes. "buffer_capacity" is how much is currently allocated,
135
144
* "buffer_length" is how much is already used.
137
size_t adjustbuffer(char **buffer, size_t buffer_length,
146
size_t incbuffer(char **buffer, size_t buffer_length,
138
147
size_t buffer_capacity){
139
148
if(buffer_length + BUFFER_SIZE > buffer_capacity){
140
149
*buffer = realloc(*buffer, buffer_capacity + BUFFER_SIZE);
150
159
* Initialize GPGME.
152
static bool init_gpgme(mandos_context *mc, const char *seckey,
161
static bool init_gpgme(const char *seckey,
153
162
const char *pubkey, const char *tempdir){
155
164
gpgme_error_t rc;
179
rc = gpgme_op_import(mc->ctx, pgp_data);
188
rc = gpgme_op_import(mc.ctx, pgp_data);
180
189
if(rc != GPG_ERR_NO_ERROR){
181
190
fprintf(stderr, "bad gpgme_op_import: %s: %s\n",
182
191
gpgme_strsource(rc), gpgme_strerror(rc));
227
236
/* Create new GPGME "context" */
228
rc = gpgme_new(&(mc->ctx));
237
rc = gpgme_new(&(mc.ctx));
229
238
if(rc != GPG_ERR_NO_ERROR){
230
239
fprintf(stderr, "bad gpgme_new: %s: %s\n",
231
240
gpgme_strsource(rc), gpgme_strerror(rc));
243
252
* Decrypt OpenPGP data.
244
253
* Returns -1 on error
246
static ssize_t pgp_packet_decrypt(const mandos_context *mc,
247
const char *cryptotext,
255
static ssize_t pgp_packet_decrypt(const char *cryptotext,
248
256
size_t crypto_size,
249
257
char **plaintext){
250
258
gpgme_data_t dh_crypto, dh_plain;
278
286
/* Decrypt data from the cryptotext data buffer to the plaintext
280
rc = gpgme_op_decrypt(mc->ctx, dh_crypto, dh_plain);
288
rc = gpgme_op_decrypt(mc.ctx, dh_crypto, dh_plain);
281
289
if(rc != GPG_ERR_NO_ERROR){
282
290
fprintf(stderr, "bad gpgme_op_decrypt: %s: %s\n",
283
291
gpgme_strsource(rc), gpgme_strerror(rc));
284
292
plaintext_length = -1;
286
294
gpgme_decrypt_result_t result;
287
result = gpgme_op_decrypt_result(mc->ctx);
295
result = gpgme_op_decrypt_result(mc.ctx);
288
296
if(result == NULL){
289
297
fprintf(stderr, "gpgme_op_decrypt_result failed\n");
327
335
*plaintext = NULL;
329
plaintext_capacity = adjustbuffer(plaintext,
337
plaintext_capacity = incbuffer(plaintext,
330
338
(size_t)plaintext_length,
331
339
plaintext_capacity);
332
340
if(plaintext_capacity == 0){
333
perror("adjustbuffer");
334
342
plaintext_length = -1;
335
343
goto decrypt_end;
382
390
fprintf(stderr, "GnuTLS: %s", string);
385
static int init_gnutls_global(mandos_context *mc,
386
const char *pubkeyfilename,
393
static int init_gnutls_global(const char *pubkeyfilename,
387
394
const char *seckeyfilename){
409
416
/* OpenPGP credentials */
410
gnutls_certificate_allocate_credentials(&mc->cred);
417
gnutls_certificate_allocate_credentials(&mc.cred);
411
418
if(ret != GNUTLS_E_SUCCESS){
412
419
fprintf(stderr, "GnuTLS memory error: %s\n", /* Spurious warning
416
423
safer_gnutls_strerror(ret));
417
424
gnutls_global_deinit();
427
434
ret = gnutls_certificate_set_openpgp_key_file
428
(mc->cred, pubkeyfilename, seckeyfilename,
435
(mc.cred, pubkeyfilename, seckeyfilename,
429
436
GNUTLS_OPENPGP_FMT_BASE64);
430
437
if(ret != GNUTLS_E_SUCCESS){
439
446
/* GnuTLS server initialization */
440
ret = gnutls_dh_params_init(&mc->dh_params);
447
ret = gnutls_dh_params_init(&mc.dh_params);
441
448
if(ret != GNUTLS_E_SUCCESS){
442
449
fprintf(stderr, "Error in GnuTLS DH parameter initialization:"
443
450
" %s\n", safer_gnutls_strerror(ret));
446
ret = gnutls_dh_params_generate2(mc->dh_params, mc->dh_bits);
453
ret = gnutls_dh_params_generate2(mc.dh_params, mc.dh_bits);
447
454
if(ret != GNUTLS_E_SUCCESS){
448
455
fprintf(stderr, "Error in GnuTLS prime generation: %s\n",
449
456
safer_gnutls_strerror(ret));
453
gnutls_certificate_set_dh_params(mc->cred, mc->dh_params);
460
gnutls_certificate_set_dh_params(mc.cred, mc.dh_params);
459
gnutls_certificate_free_credentials(mc->cred);
466
gnutls_certificate_free_credentials(mc.cred);
460
467
gnutls_global_deinit();
461
gnutls_dh_params_deinit(mc->dh_params);
468
gnutls_dh_params_deinit(mc.dh_params);
465
static int init_gnutls_session(mandos_context *mc,
466
gnutls_session_t *session){
472
static int init_gnutls_session(gnutls_session_t *session){
468
474
/* GnuTLS session creation */
469
475
ret = gnutls_init(session, GNUTLS_SERVER);
477
ret = gnutls_priority_set_direct(*session, mc->priority, &err);
483
ret = gnutls_priority_set_direct(*session, mc.priority, &err);
478
484
if(ret != GNUTLS_E_SUCCESS){
479
485
fprintf(stderr, "Syntax error at: %s\n", err);
480
486
fprintf(stderr, "GnuTLS error: %s\n",
487
493
ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,
489
495
if(ret != GNUTLS_E_SUCCESS){
490
496
fprintf(stderr, "Error setting GnuTLS credentials: %s\n",
491
497
safer_gnutls_strerror(ret));
497
503
gnutls_certificate_server_set_request(*session,
498
504
GNUTLS_CERT_IGNORE);
500
gnutls_dh_set_prime_bits(*session, mc->dh_bits);
506
gnutls_dh_set_prime_bits(*session, mc.dh_bits);
509
515
/* Called when a Mandos server is found */
510
516
static int start_mandos_communication(const char *ip, uint16_t port,
511
517
AvahiIfIndex if_index,
515
union { struct sockaddr in; struct sockaddr_in6 in6; } to;
522
struct sockaddr_in in;
523
struct sockaddr_in6 in6;
516
525
char *buffer = NULL;
517
526
char *decrypted_buffer;
518
527
size_t buffer_length = 0;
520
529
ssize_t decrypted_buffer_size;
523
char interface[IF_NAMESIZE];
524
532
gnutls_session_t session;
526
ret = init_gnutls_session(mc, &session);
533
int pf; /* Protocol family */
543
fprintf(stderr, "Bad address family: %d\n", af);
547
ret = init_gnutls_session(&session);
532
fprintf(stderr, "Setting up a tcp connection to %s, port %" PRIu16
553
fprintf(stderr, "Setting up a TCP connection to %s, port %" PRIu16
536
tcp_sd = socket(PF_INET6, SOCK_STREAM, 0);
557
tcp_sd = socket(pf, SOCK_STREAM, 0);
538
559
perror("socket");
543
if(if_indextoname((unsigned int)if_index, interface) == NULL){
544
perror("if_indextoname");
547
fprintf(stderr, "Binding to interface %s\n", interface);
550
563
memset(&to, 0, sizeof(to));
551
to.in6.sin6_family = AF_INET6;
552
/* It would be nice to have a way to detect if we were passed an
553
IPv4 address here. Now we assume an IPv6 address. */
554
ret = inet_pton(AF_INET6, ip, &to.in6.sin6_addr);
565
to.in6.sin6_family = (uint16_t)af;
566
ret = inet_pton(af, ip, &to.in6.sin6_addr);
568
to.in.sin_family = (sa_family_t)af;
569
ret = inet_pton(af, ip, &to.in.sin_addr);
556
572
perror("inet_pton");
560
576
fprintf(stderr, "Bad address: %s\n", ip);
563
to.in6.sin6_port = htons(port); /* Spurious warnings from
580
to.in6.sin6_port = htons(port); /* Spurious warnings from
582
-Wunreachable-code */
584
if(IN6_IS_ADDR_LINKLOCAL /* Spurious warnings from */
585
(&to.in6.sin6_addr)){ /* -Wstrict-aliasing=2 or lower and
587
if(if_index == AVAHI_IF_UNSPEC){
588
fprintf(stderr, "An IPv6 link-local address is incomplete"
589
" without a network interface\n");
592
/* Set the network interface number as scope */
593
to.in6.sin6_scope_id = (uint32_t)if_index;
596
to.in.sin_port = htons(port); /* Spurious warnings from
565
598
-Wunreachable-code */
567
to.in6.sin6_scope_id = (uint32_t)if_index;
570
fprintf(stderr, "Connection to: %s, port %" PRIu16 "\n", ip,
572
char addrstr[INET6_ADDRSTRLEN] = "";
573
if(inet_ntop(to.in6.sin6_family, &(to.in6.sin6_addr), addrstr,
574
sizeof(addrstr)) == NULL){
602
if(af == AF_INET6 and if_index != AVAHI_IF_UNSPEC){
603
char interface[IF_NAMESIZE];
604
if(if_indextoname((unsigned int)if_index, interface) == NULL){
605
perror("if_indextoname");
607
fprintf(stderr, "Connection to: %s%%%s, port %" PRIu16 "\n",
608
ip, interface, port);
611
fprintf(stderr, "Connection to: %s, port %" PRIu16 "\n", ip,
614
char addrstr[(INET_ADDRSTRLEN > INET6_ADDRSTRLEN) ?
615
INET_ADDRSTRLEN : INET6_ADDRSTRLEN] = "";
618
pcret = inet_ntop(af, &(to.in6.sin6_addr), addrstr,
621
pcret = inet_ntop(af, &(to.in.sin_addr), addrstr,
575
625
perror("inet_ntop");
577
627
if(strcmp(addrstr, ip) != 0){
583
ret = connect(tcp_sd, &to.in, sizeof(to));
634
ret = connect(tcp_sd, &to.in6, sizeof(to));
636
ret = connect(tcp_sd, &to.in, sizeof(to)); /* IPv4 */
585
639
perror("connect");
632
686
/* Read OpenPGP packet that contains the wanted password */
635
fprintf(stderr, "Retrieving pgp encrypted password from %s\n",
689
fprintf(stderr, "Retrieving OpenPGP encrypted password from %s\n",
640
buffer_capacity = adjustbuffer(&buffer, buffer_length,
694
buffer_capacity = incbuffer(&buffer, buffer_length,
641
695
buffer_capacity);
642
696
if(buffer_capacity == 0){
643
perror("adjustbuffer");
685
739
gnutls_bye(session, GNUTLS_SHUT_RDWR);
687
741
if(buffer_length > 0){
688
decrypted_buffer_size = pgp_packet_decrypt(mc, buffer,
742
decrypted_buffer_size = pgp_packet_decrypt(buffer,
690
744
&decrypted_buffer);
691
745
if(decrypted_buffer_size >= 0){
737
791
AVAHI_GCC_UNUSED AvahiStringList *txt,
738
792
AVAHI_GCC_UNUSED AvahiLookupResultFlags
741
mandos_context *mc = userdata;
794
AVAHI_GCC_UNUSED void* userdata){
744
797
/* Called whenever a service has been resolved successfully or
749
802
case AVAHI_RESOLVER_FAILURE:
750
803
fprintf(stderr, "(Avahi Resolver) Failed to resolve service '%s'"
751
804
" of type '%s' in domain '%s': %s\n", name, type, domain,
752
avahi_strerror(avahi_server_errno(mc->server)));
805
avahi_strerror(avahi_server_errno(mc.server)));
755
808
case AVAHI_RESOLVER_FOUND:
761
814
PRIdMAX ") on port %" PRIu16 "\n", name, host_name,
762
815
ip, (intmax_t)interface, port);
764
int ret = start_mandos_communication(ip, port, interface, mc);
817
int ret = start_mandos_communication(ip, port, interface,
818
avahi_proto_to_af(proto));
766
avahi_simple_poll_quit(mc->simple_poll);
820
avahi_simple_poll_quit(mc.simple_poll);
791
844
case AVAHI_BROWSER_FAILURE:
793
846
fprintf(stderr, "(Avahi browser) %s\n",
794
avahi_strerror(avahi_server_errno(mc->server)));
795
avahi_simple_poll_quit(mc->simple_poll);
847
avahi_strerror(avahi_server_errno(mc.server)));
848
avahi_simple_poll_quit(mc.simple_poll);
798
851
case AVAHI_BROWSER_NEW:
801
854
the callback function is called the Avahi server will free the
802
855
resolver for us. */
804
if(!(avahi_s_service_resolver_new(mc->server, interface,
857
if(!(avahi_s_service_resolver_new(mc.server, interface,
805
858
protocol, name, type, domain,
806
859
AVAHI_PROTO_INET6, 0,
807
resolve_callback, mc)))
860
resolve_callback, NULL)))
808
861
fprintf(stderr, "Avahi: Failed to resolve service '%s': %s\n",
809
name, avahi_strerror(avahi_server_errno(mc->server)));
862
name, avahi_strerror(avahi_server_errno(mc.server)));
812
865
case AVAHI_BROWSER_REMOVE:
877
sig_atomic_t quit_now = 0;
879
/* stop main loop after sigterm has been called */
880
static void handle_sigterm(__attribute__((unused)) int sig){
885
int old_errno = errno;
886
if(mc.simple_poll != NULL){
887
avahi_simple_poll_quit(mc.simple_poll);
824
892
int main(int argc, char *argv[]){
825
893
AvahiSServiceBrowser *sb = NULL;
840
908
const char *seckey = PATHDIR "/" SECKEY;
841
909
const char *pubkey = PATHDIR "/" PUBKEY;
843
mandos_context mc = { .simple_poll = NULL, .server = NULL,
844
.dh_bits = 1024, .priority = "SECURE256"
845
":!CTYPE-X.509:+CTYPE-OPENPGP" };
911
/* Initialize Mandos context */
912
mc = (mandos_context){ .simple_poll = NULL, .server = NULL,
913
.dh_bits = 1024, .priority = "SECURE256"
914
":!CTYPE-X.509:+CTYPE-OPENPGP" };
846
915
bool gnutls_initialized = false;
847
916
bool gpgme_initialized = false;
848
917
double delay = 2.5;
919
struct sigaction old_sigterm_action;
920
struct sigaction sigterm_action = { .sa_handler = handle_sigterm };
851
923
struct argp_option options[] = {
858
930
{ .name = "interface", .key = 'i',
860
.doc = "Interface that will be used to search for Mandos"
932
.doc = "Network interface that will be used to search for"
863
935
{ .name = "seckey", .key = 's',
1019
avahi_set_log_function(empty_log);
1022
/* Initialize Avahi early so avahi_simple_poll_quit() can be called
1023
from the signal handler */
1024
/* Initialize the pseudo-RNG for Avahi */
1025
srand((unsigned int) time(NULL));
1026
mc.simple_poll = avahi_simple_poll_new();
1027
if(mc.simple_poll == NULL){
1028
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1029
exitcode = EXIT_FAILURE;
1033
sigemptyset(&sigterm_action.sa_mask);
1034
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1036
perror("sigaddset");
1037
exitcode = EXIT_FAILURE;
1040
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1042
perror("sigaddset");
1043
exitcode = EXIT_FAILURE;
1046
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1048
perror("sigaddset");
1049
exitcode = EXIT_FAILURE;
1052
ret = sigaction(SIGTERM, &sigterm_action, &old_sigterm_action);
1054
perror("sigaction");
1055
exitcode = EXIT_FAILURE;
946
1059
/* If the interface is down, bring it up */
1060
if(interface[0] != '\0'){
948
1061
#ifdef __linux__
949
1062
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
950
1063
messages to mess up the prompt */
951
1064
ret = klogctl(8, NULL, 5);
1065
bool restore_loglevel = true;
1067
restore_loglevel = false;
953
1068
perror("klogctl");
1070
#endif /* __linux__ */
957
1072
sd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP);
959
1074
perror("socket");
960
1075
exitcode = EXIT_FAILURE;
961
1076
#ifdef __linux__
962
ret = klogctl(7, NULL, 0);
1077
if(restore_loglevel){
1078
ret = klogctl(7, NULL, 0);
1083
#endif /* __linux__ */
969
1086
strcpy(network.ifr_name, interface);
972
1089
perror("ioctl SIOCGIFFLAGS");
973
1090
#ifdef __linux__
974
ret = klogctl(7, NULL, 0);
1091
if(restore_loglevel){
1092
ret = klogctl(7, NULL, 0);
1097
#endif /* __linux__ */
979
1098
exitcode = EXIT_FAILURE;
986
1105
perror("ioctl SIOCSIFFLAGS");
987
1106
exitcode = EXIT_FAILURE;
988
1107
#ifdef __linux__
989
ret = klogctl(7, NULL, 0);
1108
if(restore_loglevel){
1109
ret = klogctl(7, NULL, 0);
1114
#endif /* __linux__ */
1013
1134
perror("close");
1015
1136
#ifdef __linux__
1016
/* Restores kernel loglevel to default */
1017
ret = klogctl(7, NULL, 0);
1137
if(restore_loglevel){
1138
/* Restores kernel loglevel to default */
1139
ret = klogctl(7, NULL, 0);
1144
#endif /* __linux__ */
1024
1147
uid = getuid();
1025
1148
gid = getgid();
1029
1153
perror("setgid");
1034
1158
perror("setuid");
1037
ret = init_gnutls_global(&mc, pubkey, seckey);
1161
ret = init_gnutls_global(pubkey, seckey);
1039
1163
fprintf(stderr, "init_gnutls_global failed\n");
1040
1164
exitcode = EXIT_FAILURE;
1050
1174
tempdir_created = true;
1052
if(not init_gpgme(&mc, pubkey, seckey, tempdir)){
1176
if(not init_gpgme(pubkey, seckey, tempdir)){
1053
1177
fprintf(stderr, "init_gpgme failed\n");
1054
1178
exitcode = EXIT_FAILURE;
1057
1181
gpgme_initialized = true;
1060
if_index = (AvahiIfIndex) if_nametoindex(interface);
1062
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1063
exitcode = EXIT_FAILURE;
1184
if(interface[0] != '\0'){
1185
if_index = (AvahiIfIndex) if_nametoindex(interface);
1187
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1188
exitcode = EXIT_FAILURE;
1067
1193
if(connect_to != NULL){
1084
1210
port = (uint16_t)tmpmax;
1085
1211
*address = '\0';
1086
1212
address = connect_to;
1087
ret = start_mandos_communication(address, port, if_index, &mc);
1213
/* Colon in address indicates IPv6 */
1215
if(strchr(address, ':') != NULL){
1220
ret = start_mandos_communication(address, port, if_index, af);
1089
1222
exitcode = EXIT_FAILURE;
1097
avahi_set_log_function(empty_log);
1100
/* Initialize the pseudo-RNG for Avahi */
1101
srand((unsigned int) time(NULL));
1103
/* Allocate main Avahi loop object */
1104
mc.simple_poll = avahi_simple_poll_new();
1105
if(mc.simple_poll == NULL){
1106
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1107
exitcode = EXIT_FAILURE;
1112
1230
AvahiServerConfig config;
1113
1231
/* Do not publish any local Zeroconf records */
1137
1255
/* Create the Avahi service browser */
1138
1256
sb = avahi_s_service_browser_new(mc.server, if_index,
1139
1257
AVAHI_PROTO_INET6, "_mandos._tcp",
1140
NULL, 0, browse_callback, &mc);
1258
NULL, 0, browse_callback, NULL);
1141
1259
if(sb == NULL){
1142
1260
fprintf(stderr, "Failed to create service browser: %s\n",
1143
1261
avahi_strerror(avahi_server_errno(mc.server)));