32
32
/* Needed by GPGME, specifically gpgme_data_seek() */
33
#ifndef _LARGEFILE_SOURCE
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34
#define _LARGEFILE_SOURCE
36
#ifndef _FILE_OFFSET_BITS
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37
#define _FILE_OFFSET_BITS 64
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40
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), asprintf() */
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42
#include <stdio.h> /* fprintf(), stderr, fwrite(),
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stdout, ferror(), sscanf(),
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stdout, ferror(), remove() */
41
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#include <stdint.h> /* uint16_t, uint32_t */
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#include <stddef.h> /* NULL, size_t, ssize_t */
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#include <stdlib.h> /* free(), EXIT_SUCCESS, EXIT_FAILURE,
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#include <stdlib.h> /* free(), EXIT_SUCCESS, srand(),
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#include <stdbool.h> /* bool, false, true */
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#include <string.h> /* memset(), strcmp(), strlen(),
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strerror(), asprintf(), strcpy() */
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#include <fcntl.h> /* open() */
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#include <dirent.h> /* opendir(), struct dirent, readdir()
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#include <inttypes.h> /* PRIu16, intmax_t, SCNdMAX */
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#include <inttypes.h> /* PRIu16, PRIdMAX, intmax_t,
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#include <assert.h> /* assert() */
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#include <errno.h> /* perror(), errno */
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#include <time.h> /* nanosleep(), time() */
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#include <time.h> /* nanosleep(), time(), sleep() */
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#include <net/if.h> /* ioctl, ifreq, SIOCGIFFLAGS, IFF_UP,
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SIOCSIFFLAGS, if_indextoname(),
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if_nametoindex(), IF_NAMESIZE */
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INET_ADDRSTRLEN, INET6_ADDRSTRLEN
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#include <unistd.h> /* close(), SEEK_SET, off_t, write(),
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getuid(), getgid(), setuid(),
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getuid(), getgid(), seteuid(),
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#include <arpa/inet.h> /* inet_pton(), htons */
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#include <iso646.h> /* not, or, and */
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#include <argp.h> /* struct argp_option, error_t, struct
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argp_state, struct argp,
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80
argp_parse(), ARGP_KEY_ARG,
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ARGP_KEY_END, ARGP_ERR_UNKNOWN */
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#include <signal.h> /* sigemptyset(), sigaddset(),
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sigaction(), SIGTERM, sig_atomic_t,
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#include <sysexits.h> /* EX_OSERR, EX_USAGE, EX_UNAVAILABLE,
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EX_NOHOST, EX_IOERR, EX_PROTOCOL */
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#include <sys/klog.h> /* klogctl() */
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#endif /* __linux__ */
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/* All Avahi types, constants and functions
130
142
} mandos_context;
144
/* global context so signal handler can reach it*/
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mandos_context mc = { .simple_poll = NULL, .server = NULL,
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.dh_bits = 1024, .priority = "SECURE256"
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":!CTYPE-X.509:+CTYPE-OPENPGP" };
149
sig_atomic_t quit_now = 0;
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int signal_received = 0;
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* Make room in "buffer" for at least BUFFER_SIZE additional bytes.
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* "buffer_capacity" is how much is currently allocated,
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* Make additional room in "buffer" for at least BUFFER_SIZE more
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* bytes. "buffer_capacity" is how much is currently allocated,
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* "buffer_length" is how much is already used.
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size_t adjustbuffer(char **buffer, size_t buffer_length,
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size_t incbuffer(char **buffer, size_t buffer_length,
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size_t buffer_capacity){
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if(buffer_length + BUFFER_SIZE > buffer_capacity){
140
160
*buffer = realloc(*buffer, buffer_capacity + BUFFER_SIZE);
298
317
gpgme_recipient_t recipient;
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recipient = result->recipients;
301
while(recipient != NULL){
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fprintf(stderr, "Public key algorithm: %s\n",
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gpgme_pubkey_algo_name(recipient->pubkey_algo));
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fprintf(stderr, "Key ID: %s\n", recipient->keyid);
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fprintf(stderr, "Secret key available: %s\n",
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recipient->status == GPG_ERR_NO_SECKEY
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recipient = recipient->next;
319
while(recipient != NULL){
320
fprintf(stderr, "Public key algorithm: %s\n",
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gpgme_pubkey_algo_name(recipient->pubkey_algo));
322
fprintf(stderr, "Key ID: %s\n", recipient->keyid);
323
fprintf(stderr, "Secret key available: %s\n",
324
recipient->status == GPG_ERR_NO_SECKEY
326
recipient = recipient->next;
439
455
/* GnuTLS server initialization */
440
ret = gnutls_dh_params_init(&mc->dh_params);
456
ret = gnutls_dh_params_init(&mc.dh_params);
441
457
if(ret != GNUTLS_E_SUCCESS){
442
458
fprintf(stderr, "Error in GnuTLS DH parameter initialization:"
443
459
" %s\n", safer_gnutls_strerror(ret));
446
ret = gnutls_dh_params_generate2(mc->dh_params, mc->dh_bits);
462
ret = gnutls_dh_params_generate2(mc.dh_params, mc.dh_bits);
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463
if(ret != GNUTLS_E_SUCCESS){
448
464
fprintf(stderr, "Error in GnuTLS prime generation: %s\n",
449
465
safer_gnutls_strerror(ret));
453
gnutls_certificate_set_dh_params(mc->cred, mc->dh_params);
469
gnutls_certificate_set_dh_params(mc.cred, mc.dh_params);
459
gnutls_certificate_free_credentials(mc->cred);
475
gnutls_certificate_free_credentials(mc.cred);
460
476
gnutls_global_deinit();
461
gnutls_dh_params_deinit(mc->dh_params);
477
gnutls_dh_params_deinit(mc.dh_params);
465
static int init_gnutls_session(mandos_context *mc,
466
gnutls_session_t *session){
481
static int init_gnutls_session(gnutls_session_t *session){
468
483
/* GnuTLS session creation */
469
ret = gnutls_init(session, GNUTLS_SERVER);
485
ret = gnutls_init(session, GNUTLS_SERVER);
489
} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
470
490
if(ret != GNUTLS_E_SUCCESS){
471
491
fprintf(stderr, "Error in GnuTLS session initialization: %s\n",
472
492
safer_gnutls_strerror(ret));
730
836
fprintf(stderr, "Closing TLS session\n");
733
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);
735
852
if(buffer_length > 0){
736
decrypted_buffer_size = pgp_packet_decrypt(mc, buffer,
853
ssize_t decrypted_buffer_size;
854
decrypted_buffer_size = pgp_packet_decrypt(buffer,
738
856
&decrypted_buffer);
739
857
if(decrypted_buffer_size >= 0){
741
860
while(written < (size_t) decrypted_buffer_size){
742
866
ret = (int)fwrite(decrypted_buffer + written, 1,
743
867
(size_t)decrypted_buffer_size - written,
745
869
if(ret == 0 and ferror(stdout)){
747
872
fprintf(stderr, "Error writing encrypted data: %s\n",
748
873
strerror(errno));
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878
written += (size_t)ret;
755
free(decrypted_buffer);
763
884
/* Shutdown procedure */
767
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);
771
gnutls_deinit(session);
850
991
the callback function is called the Avahi server will free the
851
992
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)))
994
if(avahi_s_service_resolver_new(mc.server, interface, protocol,
995
name, type, domain, protocol, 0,
996
resolve_callback, NULL) == NULL)
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fprintf(stderr, "Avahi: Failed to resolve service '%s': %s\n",
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name, avahi_strerror(avahi_server_errno(mc->server)));
998
name, avahi_strerror(avahi_server_errno(mc.server)));
861
1001
case AVAHI_BROWSER_REMOVE:
1013
/* stop main loop after sigterm has been called */
1014
static void handle_sigterm(int sig){
1019
signal_received = sig;
1020
int old_errno = errno;
1021
if(mc.simple_poll != NULL){
1022
avahi_simple_poll_quit(mc.simple_poll);
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* 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;
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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" */
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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",
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/* 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",
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/* Otherwise, reject non-broadcast-capable devices */
1107
if(not (flags & IFF_BROADCAST)){
1109
fprintf(stderr, "Rejecting non-broadcast interface \"%s\"\n",
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/* Accept this device */
1116
fprintf(stderr, "Interface \"%s\" is acceptable\n",
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1122
int main(int argc, char *argv[]){
874
1123
AvahiSServiceBrowser *sb = NULL;
877
1126
intmax_t tmpmax;
879
1128
int exitcode = EXIT_SUCCESS;
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const char *interface = "eth0";
1129
const char *interface = "";
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1130
struct ifreq network;
1132
bool take_down_interface = false;
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char *connect_to = NULL;
886
1135
char tempdir[] = "/tmp/mandosXXXXXX";
887
1136
bool tempdir_created = false;
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1137
AvahiIfIndex if_index = AVAHI_IF_UNSPEC;
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1138
const char *seckey = PATHDIR "/" SECKEY;
890
1139
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
1141
bool gnutls_initialized = false;
896
1142
bool gpgme_initialized = false;
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struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };
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) */
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1170
struct argp_option options[] = {
930
1200
.arg = "SECONDS",
931
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 },
933
1212
{ .name = NULL }
936
1215
error_t parse_opt(int key, char *arg,
937
1216
struct argp_state *state){
939
1219
case 128: /* --debug */
964
1244
mc.priority = arg;
966
1246
case 131: /* --delay */
967
ret = sscanf(arg, "%lf%n", &delay, &numchars);
968
if(ret < 1 or arg[numchars] != '\0'){
969
fprintf(stderr, "Bad delay\n");
1248
delay = strtof(arg, &tmp);
1249
if(errno != 0 or tmp == arg or *tmp != '\0'){
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);
978
1268
return ARGP_ERR_UNKNOWN;
983
1273
struct argp argp = { .options = options, .parser = parse_opt,
985
1275
.doc = "Mandos client -- Get and decrypt"
986
1276
" passwords from a Mandos server" };
987
ret = argp_parse(&argp, argc, argv, 0, 0, NULL);
988
if(ret == ARGP_ERR_UNKNOWN){
989
fprintf(stderr, "Unknown error while parsing arguments\n");
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;
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");
990
1318
exitcode = EXIT_FAILURE;
1323
/* Initialize Avahi early so avahi_simple_poll_quit() can be called
1324
from the signal handler */
1325
/* Initialize the pseudo-RNG for Avahi */
1326
srand((unsigned int) time(NULL));
1327
mc.simple_poll = avahi_simple_poll_new();
1328
if(mc.simple_poll == NULL){
1329
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1330
exitcode = EX_UNAVAILABLE;
1334
sigemptyset(&sigterm_action.sa_mask);
1335
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1337
perror("sigaddset");
1338
exitcode = EX_OSERR;
1341
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1343
perror("sigaddset");
1344
exitcode = EX_OSERR;
1347
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1349
perror("sigaddset");
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;
995
1397
/* If the interface is down, bring it up */
996
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 */
997
1417
#ifdef __linux__
998
1418
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
999
messages to mess up the prompt */
1419
messages about the network interface to mess up the prompt */
1000
1420
ret = klogctl(8, NULL, 5);
1001
1421
bool restore_loglevel = true;
1003
1423
restore_loglevel = false;
1004
1424
perror("klogctl");
1426
#endif /* __linux__ */
1008
1428
sd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP);
1010
1430
perror("socket");
1011
exitcode = EXIT_FAILURE;
1431
exitcode = EX_OSERR;
1012
1432
#ifdef __linux__
1013
1433
if(restore_loglevel){
1014
1434
ret = klogctl(7, NULL, 0);
1077
1520
perror("klogctl");
1097
ret = init_gnutls_global(&mc, pubkey, seckey);
1523
#endif /* __linux__ */
1524
/* Lower privileges */
1526
if(take_down_interface){
1527
/* Lower privileges */
1533
/* Lower privileges permanently */
1545
ret = init_gnutls_global(pubkey, seckey);
1099
1547
fprintf(stderr, "init_gnutls_global failed\n");
1100
exitcode = EXIT_FAILURE;
1548
exitcode = EX_UNAVAILABLE;
1103
1551
gnutls_initialized = true;
1558
tempdir_created = true;
1106
1559
if(mkdtemp(tempdir) == NULL){
1560
tempdir_created = false;
1107
1561
perror("mkdtemp");
1110
tempdir_created = true;
1112
if(not init_gpgme(&mc, pubkey, seckey, tempdir)){
1569
if(not init_gpgme(pubkey, seckey, tempdir)){
1113
1570
fprintf(stderr, "init_gpgme failed\n");
1114
exitcode = EXIT_FAILURE;
1571
exitcode = EX_UNAVAILABLE;
1117
1574
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
1581
if(connect_to != NULL){
1200
1662
if(mc.server == NULL){
1201
1663
fprintf(stderr, "Failed to create Avahi server: %s\n",
1202
1664
avahi_strerror(error));
1203
exitcode = EXIT_FAILURE;
1665
exitcode = EX_UNAVAILABLE;
1207
1673
/* Create the Avahi service browser */
1208
1674
sb = avahi_s_service_browser_new(mc.server, if_index,
1209
AVAHI_PROTO_INET6, "_mandos._tcp",
1210
NULL, 0, browse_callback, &mc);
1675
AVAHI_PROTO_UNSPEC, "_mandos._tcp",
1676
NULL, 0, browse_callback, NULL);
1211
1677
if(sb == NULL){
1212
1678
fprintf(stderr, "Failed to create service browser: %s\n",
1213
1679
avahi_strerror(avahi_server_errno(mc.server)));
1214
exitcode = EXIT_FAILURE;
1680
exitcode = EX_UNAVAILABLE;