9
9
* "browse_callback", and parts of "main".
11
11
* Everything else is
12
* Copyright © 2008-2011 Teddy Hogeborn
13
* Copyright © 2008-2011 Björn Påhlsson
12
* Copyright © 2008,2009 Teddy Hogeborn
13
* Copyright © 2008,2009 Björn Påhlsson
15
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* This program is free software: you can redistribute it and/or
16
16
* modify it under the terms of the GNU General Public License as
43
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stdout, ferror(), remove() */
44
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#include <stdint.h> /* uint16_t, uint32_t */
45
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#include <stddef.h> /* NULL, size_t, ssize_t */
46
#include <stdlib.h> /* free(), EXIT_SUCCESS, srand(),
46
#include <stdlib.h> /* free(), EXIT_SUCCESS, EXIT_FAILURE,
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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() */
64
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#include <assert.h> /* assert() */
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#include <errno.h> /* perror(), errno */
66
#include <time.h> /* nanosleep(), time(), sleep() */
66
#include <time.h> /* nanosleep(), time() */
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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(), seteuid(),
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getuid(), getgid(), setuid(),
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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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#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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static const char mandos_protocol_version[] = "1";
128
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const char *argp_program_version = "mandos-client " VERSION;
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const char *argp_program_bug_address = "<mandos@fukt.bsnet.se>";
130
static const char sys_class_net[] = "/sys/class/net";
131
char *connect_to = NULL;
133
129
/* Used for passing in values through the Avahi callback functions */
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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 additional room in "buffer" for at least BUFFER_SIZE more
154
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* bytes. "buffer_capacity" is how much is currently allocated,
481
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static int init_gnutls_session(gnutls_session_t *session){
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/* GnuTLS session creation */
485
ret = gnutls_init(session, GNUTLS_SERVER);
489
} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
477
ret = gnutls_init(session, GNUTLS_SERVER);
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if(ret != GNUTLS_E_SUCCESS){
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fprintf(stderr, "Error in GnuTLS session initialization: %s\n",
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safer_gnutls_strerror(ret));
498
ret = gnutls_priority_set_direct(*session, mc.priority, &err);
500
gnutls_deinit(*session);
503
} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
485
ret = gnutls_priority_set_direct(*session, mc.priority, &err);
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if(ret != GNUTLS_E_SUCCESS){
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fprintf(stderr, "Syntax error at: %s\n", err);
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fprintf(stderr, "GnuTLS error: %s\n",
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ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,
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gnutls_deinit(*session);
520
} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
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ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,
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if(ret != GNUTLS_E_SUCCESS){
522
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fprintf(stderr, "Error setting GnuTLS credentials: %s\n",
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safer_gnutls_strerror(ret));
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/* ignore client certificate if any. */
529
gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);
505
gnutls_certificate_server_set_request(*session,
531
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gnutls_dh_set_prime_bits(*session, mc.dh_bits);
537
514
static void empty_log(__attribute__((unused)) AvahiLogLevel level,
538
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__attribute__((unused)) const char *txt){}
517
sig_atomic_t quit_now = 0;
518
int signal_received = 0;
540
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/* Called when a Mandos server is found */
541
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static int start_mandos_communication(const char *ip, uint16_t port,
542
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AvahiIfIndex if_index,
544
int ret, tcp_sd = -1;
547
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struct sockaddr_in in;
548
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struct sockaddr_in6 in6;
550
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char *buffer = NULL;
551
char *decrypted_buffer = NULL;
531
char *decrypted_buffer;
552
532
size_t buffer_length = 0;
553
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size_t buffer_capacity = 0;
534
ssize_t decrypted_buffer_size;
556
537
gnutls_session_t session;
557
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int pf; /* Protocol family */
630
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if(if_index == AVAHI_IF_UNSPEC){
631
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fprintf(stderr, "An IPv6 link-local address is incomplete"
632
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" without a network interface\n");
636
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/* Set the network interface number as scope */
637
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to.in6.sin6_scope_id = (uint32_t)if_index;
687
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if(af == AF_INET6){
688
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ret = connect(tcp_sd, &to.in6, sizeof(to));
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ret = connect(tcp_sd, &to.in, sizeof(to)); /* IPv4 */
693
if ((errno != ECONNREFUSED and errno != ENETUNREACH) or debug){
706
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const char *out = mandos_protocol_version;
737
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fprintf(stderr, "Establishing TLS session with %s\n", ip);
745
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gnutls_transport_set_ptr(session, (gnutls_transport_ptr_t) tcp_sd);
753
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ret = gnutls_handshake(session);
758
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} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
760
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if(ret != GNUTLS_E_SUCCESS){
805
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case GNUTLS_E_AGAIN:
807
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case GNUTLS_E_REHANDSHAKE:
809
719
ret = gnutls_handshake(session);
815
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} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
817
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fprintf(stderr, "*** GnuTLS Re-handshake failed ***\n");
818
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gnutls_perror(ret);
824
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fprintf(stderr, "Unknown error while reading data from"
825
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" encrypted session with Mandos server\n");
826
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gnutls_bye(session, GNUTLS_SHUT_RDWR);
836
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fprintf(stderr, "Closing TLS session\n");
845
ret = gnutls_bye(session, GNUTLS_SHUT_RDWR);
850
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
744
gnutls_bye(session, GNUTLS_SHUT_RDWR);
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if(buffer_length > 0){
853
ssize_t decrypted_buffer_size;
854
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decrypted_buffer_size = pgp_packet_decrypt(buffer,
856
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&decrypted_buffer);
857
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if(decrypted_buffer_size >= 0){
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while(written < (size_t) decrypted_buffer_size){
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ret = (int)fwrite(decrypted_buffer + written, 1,
867
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(size_t)decrypted_buffer_size - written,
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if(ret == 0 and ferror(stdout)){
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fprintf(stderr, "Error writing encrypted data: %s\n",
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strerror(errno));
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written += (size_t)ret;
766
free(decrypted_buffer);
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/* Shutdown procedure */
889
free(decrypted_buffer);
892
ret = (int)TEMP_FAILURE_RETRY(close(tcp_sd));
900
gnutls_deinit(session);
778
ret = (int)TEMP_FAILURE_RETRY(close(tcp_sd));
782
gnutls_deinit(session);
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errno = old_errno;
1028
* 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" */
1052
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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int main(int argc, char *argv[]){
1123
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AvahiSServiceBrowser *sb = NULL;
1126
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intmax_t tmpmax;
1128
905
int exitcode = EXIT_SUCCESS;
1129
const char *interface = "";
906
const char *interface = "eth0";
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struct ifreq network;
1132
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bool take_down_interface = false;
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char *connect_to = NULL;
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char tempdir[] = "/tmp/mandosXXXXXX";
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bool tempdir_created = false;
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AvahiIfIndex if_index = AVAHI_IF_UNSPEC;
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bool gpgme_initialized = false;
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float delay = 2.5f;
1145
struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };
923
struct sigaction old_sigterm_action;
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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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struct argp_option options[] = {
1171
928
{ .name = "debug", .key = 128,
1200
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.arg = "SECONDS",
1201
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.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 },
1212
960
{ .name = NULL }
1215
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error_t parse_opt(int key, char *arg,
1216
964
struct argp_state *state){
1219
966
case 128: /* --debug */
1236
983
tmpmax = strtoimax(arg, &tmp, 10);
1237
984
if(errno != 0 or tmp == arg or *tmp != '\0'
1238
985
or tmpmax != (typeof(mc.dh_bits))tmpmax){
1239
argp_error(state, "Bad number of DH bits");
986
fprintf(stderr, "Bad number of DH bits\n");
1241
989
mc.dh_bits = (typeof(mc.dh_bits))tmpmax;
1248
996
delay = strtof(arg, &tmp);
1249
997
if(errno != 0 or tmp == arg or *tmp != '\0'){
1250
argp_error(state, "Bad delay");
998
fprintf(stderr, "Bad delay\n");
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);
1268
1007
return ARGP_ERR_UNKNOWN;
1273
1012
struct argp argp = { .options = options, .parser = parse_opt,
1274
1013
.args_doc = "",
1275
1014
.doc = "Mandos client -- Get and decrypt"
1276
1015
" passwords from a Mandos server" };
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;
1016
ret = argp_parse(&argp, argc, argv, 0, 0, NULL);
1017
if(ret == ARGP_ERR_UNKNOWN){
1018
fprintf(stderr, "Unknown error while parsing arguments\n");
1019
exitcode = EXIT_FAILURE;
1295
1025
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");
1318
exitcode = EXIT_FAILURE;
1323
1028
/* Initialize Avahi early so avahi_simple_poll_quit() can be called
1324
1029
from the signal handler */
1335
1040
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1337
1042
perror("sigaddset");
1338
exitcode = EX_OSERR;
1043
exitcode = EXIT_FAILURE;
1341
1046
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1343
1048
perror("sigaddset");
1344
exitcode = EX_OSERR;
1049
exitcode = EXIT_FAILURE;
1347
1052
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1349
1054
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;
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;
1397
1077
/* If the interface is down, bring it up */
1398
if(strcmp(interface, "none") != 0){
1078
if(interface[0] != '\0'){
1399
1079
if_index = (AvahiIfIndex) if_nametoindex(interface);
1400
1080
if(if_index == 0){
1401
1081
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1402
exitcode = EX_UNAVAILABLE;
1082
exitcode = EXIT_FAILURE;
1410
/* Re-raise priviliges */
1417
1090
#ifdef __linux__
1418
1091
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1419
messages about the network interface to mess up the prompt */
1092
messages to mess up the prompt */
1420
1093
ret = klogctl(8, NULL, 5);
1421
1094
bool restore_loglevel = true;
1472
1133
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1474
1135
take_down_interface = false;
1475
perror("ioctl SIOCSIFFLAGS +IFF_UP");
1476
exitcode = EX_OSERR;
1136
perror("ioctl SIOCSIFFLAGS");
1137
exitcode = EXIT_FAILURE;
1477
1138
#ifdef __linux__
1478
1139
if(restore_loglevel){
1479
1140
ret = klogctl(7, NULL, 0);
1569
1227
if(not init_gpgme(pubkey, seckey, tempdir)){
1570
1228
fprintf(stderr, "init_gpgme failed\n");
1571
exitcode = EX_UNAVAILABLE;
1229
exitcode = EXIT_FAILURE;
1574
1232
gpgme_initialized = true;
1624
while(not quit_now){
1625
ret = start_mandos_communication(address, port, if_index, af);
1626
if(quit_now or ret == 0){
1282
ret = start_mandos_communication(address, port, if_index, af);
1284
exitcode = EXIT_FAILURE;
1633
1286
exitcode = EXIT_SUCCESS;
1722
1374
/* Take down the network interface */
1723
1375
if(take_down_interface){
1724
/* Re-raise priviliges */
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");
1731
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1733
perror("ioctl SIOCGIFFLAGS");
1734
} else if(network.ifr_flags & IFF_UP) {
1735
network.ifr_flags &= ~(short)IFF_UP; /* clear flag */
1736
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1738
perror("ioctl SIOCSIFFLAGS -IFF_UP");
1741
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1745
/* Lower privileges permanently */
1386
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1799
sigemptyset(&old_sigterm_action.sa_mask);
1800
old_sigterm_action.sa_handler = SIG_DFL;
1801
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
1802
&old_sigterm_action,
1437
ret = sigaction(signal_received, &old_sigterm_action, NULL);
1805
1439
perror("sigaction");
1808
ret = raise(signal_received);
1809
} while(ret != 0 and errno == EINTR);
1814
TEMP_FAILURE_RETRY(pause());
1441
raise(signal_received);
1817
1444
return exitcode;