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() */
40
44
#include <stdint.h> /* uint16_t, uint32_t */
41
45
#include <stddef.h> /* NULL, size_t, ssize_t */
42
46
#include <stdlib.h> /* free(), EXIT_SUCCESS, EXIT_FAILURE,
47
srand(), strtof(), abort() */
44
48
#include <stdbool.h> /* bool, false, true */
45
49
#include <string.h> /* memset(), strcmp(), strlen(),
46
50
strerror(), asprintf(), strcpy() */
67
71
INET_ADDRSTRLEN, INET6_ADDRSTRLEN
69
73
#include <unistd.h> /* close(), SEEK_SET, off_t, write(),
70
getuid(), getgid(), setuid(),
74
getuid(), getgid(), seteuid(),
72
76
#include <arpa/inet.h> /* inet_pton(), htons */
73
77
#include <iso646.h> /* not, or, and */
74
78
#include <argp.h> /* struct argp_option, error_t, struct
76
80
argp_parse(), ARGP_KEY_ARG,
77
81
ARGP_KEY_END, ARGP_ERR_UNKNOWN */
78
82
#include <signal.h> /* sigemptyset(), sigaddset(),
79
sigaction(), SIGTERM, sigaction,
83
sigaction(), SIGTERM, sig_atomic_t,
85
#include <sysexits.h> /* EX_OSERR, EX_USAGE */
83
88
#include <sys/klog.h> /* klogctl() */
138
143
.dh_bits = 1024, .priority = "SECURE256"
139
144
":!CTYPE-X.509:+CTYPE-OPENPGP" };
146
sig_atomic_t quit_now = 0;
147
int signal_received = 0;
142
150
* Make additional room in "buffer" for at least BUFFER_SIZE more
143
151
* bytes. "buffer_capacity" is how much is currently allocated,
306
314
gpgme_recipient_t recipient;
307
315
recipient = result->recipients;
309
while(recipient != NULL){
310
fprintf(stderr, "Public key algorithm: %s\n",
311
gpgme_pubkey_algo_name(recipient->pubkey_algo));
312
fprintf(stderr, "Key ID: %s\n", recipient->keyid);
313
fprintf(stderr, "Secret key available: %s\n",
314
recipient->status == GPG_ERR_NO_SECKEY
316
recipient = recipient->next;
316
while(recipient != NULL){
317
fprintf(stderr, "Public key algorithm: %s\n",
318
gpgme_pubkey_algo_name(recipient->pubkey_algo));
319
fprintf(stderr, "Key ID: %s\n", recipient->keyid);
320
fprintf(stderr, "Secret key available: %s\n",
321
recipient->status == GPG_ERR_NO_SECKEY
323
recipient = recipient->next;
472
478
static int init_gnutls_session(gnutls_session_t *session){
474
480
/* GnuTLS session creation */
475
ret = gnutls_init(session, GNUTLS_SERVER);
482
ret = gnutls_init(session, GNUTLS_SERVER);
486
} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
476
487
if(ret != GNUTLS_E_SUCCESS){
477
488
fprintf(stderr, "Error in GnuTLS session initialization: %s\n",
478
489
safer_gnutls_strerror(ret));
483
ret = gnutls_priority_set_direct(*session, mc.priority, &err);
495
ret = gnutls_priority_set_direct(*session, mc.priority, &err);
497
gnutls_deinit(*session);
500
} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
484
501
if(ret != GNUTLS_E_SUCCESS){
485
502
fprintf(stderr, "Syntax error at: %s\n", err);
486
503
fprintf(stderr, "GnuTLS error: %s\n",
493
ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,
511
ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,
514
gnutls_deinit(*session);
517
} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
495
518
if(ret != GNUTLS_E_SUCCESS){
496
519
fprintf(stderr, "Error setting GnuTLS credentials: %s\n",
497
520
safer_gnutls_strerror(ret));
502
525
/* ignore client certificate if any. */
503
gnutls_certificate_server_set_request(*session,
526
gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);
506
528
gnutls_dh_set_prime_bits(*session, mc.dh_bits);
516
538
static int start_mandos_communication(const char *ip, uint16_t port,
517
539
AvahiIfIndex if_index,
541
int ret, tcp_sd = -1;
522
544
struct sockaddr_in in;
523
545
struct sockaddr_in6 in6;
525
547
char *buffer = NULL;
526
char *decrypted_buffer;
548
char *decrypted_buffer = NULL;
527
549
size_t buffer_length = 0;
528
550
size_t buffer_capacity = 0;
529
ssize_t decrypted_buffer_size;
532
553
gnutls_session_t session;
533
554
int pf; /* Protocol family */
557
582
tcp_sd = socket(pf, SOCK_STREAM, 0);
559
584
perror("socket");
563
592
memset(&to, 0, sizeof(to));
564
593
if(af == AF_INET6){
565
to.in6.sin6_family = (uint16_t)af;
594
to.in6.sin6_family = (sa_family_t)af;
566
595
ret = inet_pton(af, ip, &to.in6.sin6_addr);
567
596
} else { /* IPv4 */
568
597
to.in.sin_family = (sa_family_t)af;
587
616
if(if_index == AVAHI_IF_UNSPEC){
588
617
fprintf(stderr, "An IPv6 link-local address is incomplete"
589
618
" without a network interface\n");
592
621
/* Set the network interface number as scope */
593
622
to.in6.sin6_scope_id = (uint32_t)if_index;
668
712
fprintf(stderr, "Establishing TLS session with %s\n", ip);
671
719
gnutls_transport_set_ptr(session, (gnutls_transport_ptr_t) tcp_sd);
674
726
ret = gnutls_handshake(session);
675
730
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
677
732
if(ret != GNUTLS_E_SUCCESS){
710
772
case GNUTLS_E_AGAIN:
712
774
case GNUTLS_E_REHANDSHAKE:
714
776
ret = gnutls_handshake(session);
715
781
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
717
783
fprintf(stderr, "*** GnuTLS Re-handshake failed ***\n");
718
784
gnutls_perror(ret);
724
789
fprintf(stderr, "Unknown error while reading data from"
725
790
" encrypted session with Mandos server\n");
727
791
gnutls_bye(session, GNUTLS_SHUT_RDWR);
736
800
fprintf(stderr, "Closing TLS session\n");
739
gnutls_bye(session, GNUTLS_SHUT_RDWR);
808
ret = gnutls_bye(session, GNUTLS_SHUT_RDWR);
812
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
741
814
if(buffer_length > 0){
815
ssize_t decrypted_buffer_size;
742
816
decrypted_buffer_size = pgp_packet_decrypt(buffer,
744
818
&decrypted_buffer);
745
819
if(decrypted_buffer_size >= 0){
747
822
while(written < (size_t) decrypted_buffer_size){
748
827
ret = (int)fwrite(decrypted_buffer + written, 1,
749
828
(size_t)decrypted_buffer_size - written,
876
sig_atomic_t quit_now = 0;
878
964
/* stop main loop after sigterm has been called */
879
static void handle_sigterm(__attribute__((unused)) int sig){
965
static void handle_sigterm(int sig){
970
signal_received = sig;
884
971
int old_errno = errno;
885
972
if(mc.simple_poll != NULL){
886
973
avahi_simple_poll_quit(mc.simple_poll);
911
999
bool gpgme_initialized = false;
912
1000
float delay = 2.5f;
914
struct sigaction old_sigterm_action;
1002
struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };
915
1003
struct sigaction sigterm_action = { .sa_handler = handle_sigterm };
1008
/* Lower any group privileges we might have, just to be safe */
1015
/* Lower user privileges (temporarily) */
918
1027
struct argp_option options[] = {
919
1028
{ .name = "debug", .key = 128,
948
1057
.arg = "SECONDS",
949
1058
.doc = "Maximum delay to wait for interface startup",
1061
* These reproduce what we would get without ARGP_NO_HELP
1063
{ .name = "help", .key = '?',
1064
.doc = "Give this help list", .group = -1 },
1065
{ .name = "usage", .key = -3,
1066
.doc = "Give a short usage message", .group = -1 },
1067
{ .name = "version", .key = 'V',
1068
.doc = "Print program version", .group = -1 },
951
1069
{ .name = NULL }
954
1072
error_t parse_opt(int key, char *arg,
955
1073
struct argp_state *state){
957
1076
case 128: /* --debug */
974
1093
tmpmax = strtoimax(arg, &tmp, 10);
975
1094
if(errno != 0 or tmp == arg or *tmp != '\0'
976
1095
or tmpmax != (typeof(mc.dh_bits))tmpmax){
977
fprintf(stderr, "Bad number of DH bits\n");
1096
argp_error(state, "Bad number of DH bits");
980
1098
mc.dh_bits = (typeof(mc.dh_bits))tmpmax;
987
1105
delay = strtof(arg, &tmp);
988
1106
if(errno != 0 or tmp == arg or *tmp != '\0'){
989
fprintf(stderr, "Bad delay\n");
1107
argp_error(state, "Bad delay");
1111
* These reproduce what we would get without ARGP_NO_HELP
1113
case '?': /* --help */
1114
argp_state_help(state, state->out_stream,
1115
(ARGP_HELP_STD_HELP | ARGP_HELP_EXIT_ERR)
1116
& ~(unsigned int)ARGP_HELP_EXIT_OK);
1117
case -3: /* --usage */
1118
argp_state_help(state, state->out_stream,
1119
ARGP_HELP_USAGE | ARGP_HELP_EXIT_ERR);
1120
case 'V': /* --version */
1121
fprintf(state->out_stream, "%s\n", argp_program_version);
1122
exit(argp_err_exit_status);
998
1125
return ARGP_ERR_UNKNOWN;
1003
1130
struct argp argp = { .options = options, .parser = parse_opt,
1004
1131
.args_doc = "",
1005
1132
.doc = "Mandos client -- Get and decrypt"
1006
1133
" passwords from a Mandos server" };
1007
ret = argp_parse(&argp, argc, argv, 0, 0, NULL);
1008
if(ret == ARGP_ERR_UNKNOWN){
1009
fprintf(stderr, "Unknown error while parsing arguments\n");
1010
exitcode = EXIT_FAILURE;
1134
ret = argp_parse(&argp, argc, argv,
1135
ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);
1142
perror("argp_parse");
1143
exitcode = EX_OSERR;
1146
exitcode = EX_USAGE;
1046
1182
exitcode = EXIT_FAILURE;
1049
ret = sigaction(SIGTERM, &sigterm_action, &old_sigterm_action);
1051
perror("sigaction");
1052
exitcode = EXIT_FAILURE;
1185
/* Need to check if the handler is SIG_IGN before handling:
1186
| [[info:libc:Initial Signal Actions]] |
1187
| [[info:libc:Basic Signal Handling]] |
1189
ret = sigaction(SIGINT, NULL, &old_sigterm_action);
1191
perror("sigaction");
1192
return EXIT_FAILURE;
1194
if(old_sigterm_action.sa_handler != SIG_IGN){
1195
ret = sigaction(SIGINT, &sigterm_action, NULL);
1197
perror("sigaction");
1198
exitcode = EXIT_FAILURE;
1202
ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
1204
perror("sigaction");
1205
return EXIT_FAILURE;
1207
if(old_sigterm_action.sa_handler != SIG_IGN){
1208
ret = sigaction(SIGHUP, &sigterm_action, NULL);
1210
perror("sigaction");
1211
exitcode = EXIT_FAILURE;
1215
ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
1217
perror("sigaction");
1218
return EXIT_FAILURE;
1220
if(old_sigterm_action.sa_handler != SIG_IGN){
1221
ret = sigaction(SIGTERM, &sigterm_action, NULL);
1223
perror("sigaction");
1224
exitcode = EXIT_FAILURE;
1056
1229
/* If the interface is down, bring it up */
1057
1230
if(interface[0] != '\0'){
1231
if_index = (AvahiIfIndex) if_nametoindex(interface);
1233
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1234
exitcode = EXIT_FAILURE;
1242
/* Re-raise priviliges */
1058
1249
#ifdef __linux__
1059
1250
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1060
messages to mess up the prompt */
1251
messages about the network interface to mess up the prompt */
1061
1252
ret = klogctl(8, NULL, 5);
1062
1253
bool restore_loglevel = true;
1094
1291
#endif /* __linux__ */
1095
1292
exitcode = EXIT_FAILURE;
1293
/* Lower privileges */
1098
1301
if((network.ifr_flags & IFF_UP) == 0){
1099
1302
network.ifr_flags |= IFF_UP;
1303
take_down_interface = true;
1100
1304
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1306
take_down_interface = false;
1102
1307
perror("ioctl SIOCSIFFLAGS");
1103
1308
exitcode = EXIT_FAILURE;
1104
1309
#ifdef __linux__
1164
1383
gnutls_initialized = true;
1390
tempdir_created = true;
1167
1391
if(mkdtemp(tempdir) == NULL){
1392
tempdir_created = false;
1168
1393
perror("mkdtemp");
1171
tempdir_created = true;
1173
1401
if(not init_gpgme(pubkey, seckey, tempdir)){
1174
1402
fprintf(stderr, "init_gpgme failed\n");
1178
1406
gpgme_initialized = true;
1181
if(interface[0] != '\0'){
1182
if_index = (AvahiIfIndex) if_nametoindex(interface);
1184
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1185
exitcode = EXIT_FAILURE;
1190
1413
if(connect_to != NULL){
1253
1499
/* Create the Avahi service browser */
1254
1500
sb = avahi_s_service_browser_new(mc.server, if_index,
1255
1501
AVAHI_PROTO_UNSPEC, "_mandos._tcp",
1295
1545
gpgme_release(mc.ctx);
1548
/* Take down the network interface */
1549
if(take_down_interface){
1550
/* Re-raise priviliges */
1557
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1559
perror("ioctl SIOCGIFFLAGS");
1560
} else if(network.ifr_flags & IFF_UP) {
1561
network.ifr_flags &= ~(short)IFF_UP; /* clear flag */
1562
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1564
perror("ioctl SIOCSIFFLAGS");
1567
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1571
/* Lower privileges permanently */
1298
1580
/* Removes the temp directory used by GPGME */
1299
1581
if(tempdir_created){
1625
sigemptyset(&old_sigterm_action.sa_mask);
1626
old_sigterm_action.sa_handler = SIG_DFL;
1627
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
1628
&old_sigterm_action,
1631
perror("sigaction");
1634
ret = raise(signal_received);
1635
} while(ret != 0 and errno == EINTR);
1640
TEMP_FAILURE_RETRY(pause());
1342
1643
return exitcode;