72
67
INET_ADDRSTRLEN, INET6_ADDRSTRLEN
74
69
#include <unistd.h> /* close(), SEEK_SET, off_t, write(),
75
getuid(), getgid(), seteuid(),
77
#include <arpa/inet.h> /* inet_pton(), htons, inet_ntop() */
70
getuid(), getgid(), setuid(),
72
#include <arpa/inet.h> /* inet_pton(), htons */
78
73
#include <iso646.h> /* not, or, and */
79
74
#include <argp.h> /* struct argp_option, error_t, struct
80
75
argp_state, struct argp,
81
76
argp_parse(), ARGP_KEY_ARG,
82
77
ARGP_KEY_END, ARGP_ERR_UNKNOWN */
83
78
#include <signal.h> /* sigemptyset(), sigaddset(),
84
sigaction(), SIGTERM, sig_atomic_t,
86
#include <sysexits.h> /* EX_OSERR, EX_USAGE, EX_UNAVAILABLE,
87
EX_NOHOST, EX_IOERR, EX_PROTOCOL */
79
sigaction(), SIGTERM, sigaction,
90
83
#include <sys/klog.h> /* klogctl() */
1072
/* Signal handler that stops main loop after SIGTERM */
1073
static void handle_sigterm(int sig){
875
sig_atomic_t quit_now = 0;
877
static void handle_sigterm(__attribute__((unused)) int sig){
1078
signal_received = sig;
1079
882
int old_errno = errno;
1080
/* set main loop to exit */
1081
883
if(mc.simple_poll != NULL){
1082
884
avahi_simple_poll_quit(mc.simple_poll);
1084
886
errno = old_errno;
1088
* This function determines if a directory entry in /sys/class/net
1089
* corresponds to an acceptable network device.
1090
* (This function is passed to scandir(3) as a filter function.)
1092
int good_interface(const struct dirent *if_entry){
1094
char *flagname = NULL;
1095
if(if_entry->d_name[0] == '.'){
1098
int ret = asprintf(&flagname, "%s/%s/flags", sys_class_net,
1101
perror_plus("asprintf");
1104
int flags_fd = (int)TEMP_FAILURE_RETRY(open(flagname, O_RDONLY));
1106
perror_plus("open");
1111
typedef short ifreq_flags; /* ifreq.ifr_flags in netdevice(7) */
1112
/* read line from flags_fd */
1113
ssize_t to_read = 2+(sizeof(ifreq_flags)*2)+1; /* "0x1003\n" */
1114
char *flagstring = malloc((size_t)to_read+1); /* +1 for final \0 */
1115
flagstring[(size_t)to_read] = '\0';
1116
if(flagstring == NULL){
1117
perror_plus("malloc");
1122
ssret = (ssize_t)TEMP_FAILURE_RETRY(read(flags_fd, flagstring,
1125
perror_plus("read");
1139
tmpmax = strtoimax(flagstring, &tmp, 0);
1140
if(errno != 0 or tmp == flagstring or (*tmp != '\0'
1141
and not (isspace(*tmp)))
1142
or tmpmax != (ifreq_flags)tmpmax){
1144
fprintf(stderr, "Invalid flags \"%s\" for interface \"%s\"\n",
1145
flagstring, if_entry->d_name);
1151
ifreq_flags flags = (ifreq_flags)tmpmax;
1152
/* Reject the loopback device */
1153
if(flags & IFF_LOOPBACK){
1155
fprintf(stderr, "Rejecting loopback interface \"%s\"\n",
1160
/* Accept point-to-point devices only if connect_to is specified */
1161
if(connect_to != NULL and (flags & IFF_POINTOPOINT)){
1163
fprintf(stderr, "Accepting point-to-point interface \"%s\"\n",
1168
/* Otherwise, reject non-broadcast-capable devices */
1169
if(not (flags & IFF_BROADCAST)){
1171
fprintf(stderr, "Rejecting non-broadcast interface \"%s\"\n",
1176
/* Reject non-ARP interfaces (including dummy interfaces) */
1177
if(flags & IFF_NOARP){
1179
fprintf(stderr, "Rejecting non-ARP interface \"%s\"\n",
1184
/* Accept this device */
1186
fprintf(stderr, "Interface \"%s\" is acceptable\n",
1192
int notdotentries(const struct dirent *direntry){
1193
/* Skip "." and ".." */
1194
if(direntry->d_name[0] == '.'
1195
and (direntry->d_name[1] == '\0'
1196
or (direntry->d_name[1] == '.'
1197
and direntry->d_name[2] == '\0'))){
1203
int avahi_loop_with_timeout(AvahiSimplePoll *s, int retry_interval){
1205
struct timespec now;
1206
struct timespec waited_time;
1207
intmax_t block_time;
1210
if(mc.current_server == NULL){
1213
"Wait until first server is found. No timeout!\n");
1215
ret = avahi_simple_poll_iterate(s, -1);
1218
fprintf(stderr, "Check current_server if we should run it,"
1221
/* the current time */
1222
ret = clock_gettime(CLOCK_MONOTONIC, &now);
1224
perror_plus("clock_gettime");
1227
/* Calculating in ms how long time between now and server
1228
who we visted longest time ago. Now - last seen. */
1229
waited_time.tv_sec = (now.tv_sec
1230
- mc.current_server->last_seen.tv_sec);
1231
waited_time.tv_nsec = (now.tv_nsec
1232
- mc.current_server->last_seen.tv_nsec);
1233
/* total time is 10s/10,000ms.
1234
Converting to s from ms by dividing by 1,000,
1235
and ns to ms by dividing by 1,000,000. */
1236
block_time = ((retry_interval
1237
- ((intmax_t)waited_time.tv_sec * 1000))
1238
- ((intmax_t)waited_time.tv_nsec / 1000000));
1241
fprintf(stderr, "Blocking for %ld ms\n", block_time);
1244
if(block_time <= 0){
1245
ret = start_mandos_communication(mc.current_server->ip,
1246
mc.current_server->port,
1247
mc.current_server->if_index,
1248
mc.current_server->af);
1250
avahi_simple_poll_quit(mc.simple_poll);
1253
ret = clock_gettime(CLOCK_MONOTONIC,
1254
&mc.current_server->last_seen);
1256
perror_plus("clock_gettime");
1259
mc.current_server = mc.current_server->next;
1260
block_time = 0; /* Call avahi to find new Mandos
1261
servers, but don't block */
1264
ret = avahi_simple_poll_iterate(s, (int)block_time);
1267
if (ret > 0 or errno != EINTR) {
1268
return (ret != 1) ? ret : 0;
1274
889
int main(int argc, char *argv[]){
1275
890
AvahiSServiceBrowser *sb = NULL;
1278
893
intmax_t tmpmax;
1280
895
int exitcode = EXIT_SUCCESS;
1281
const char *interface = "";
896
const char *interface = "eth0";
1282
897
struct ifreq network;
1284
bool take_down_interface = false;
901
char *connect_to = NULL;
1287
902
char tempdir[] = "/tmp/mandosXXXXXX";
1288
903
bool tempdir_created = false;
1289
904
AvahiIfIndex if_index = AVAHI_IF_UNSPEC;
1290
905
const char *seckey = PATHDIR "/" SECKEY;
1291
906
const char *pubkey = PATHDIR "/" PUBKEY;
908
/* Initialize Mandos context */
909
mc = (mandos_context){ .simple_poll = NULL, .server = NULL,
910
.dh_bits = 1024, .priority = "SECURE256"
911
":!CTYPE-X.509:+CTYPE-OPENPGP" };
1293
912
bool gnutls_initialized = false;
1294
913
bool gpgme_initialized = false;
1296
double retry_interval = 10; /* 10s between trying a server and
1297
retrying the same server again */
1299
struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };
916
struct sigaction old_sigterm_action;
1300
917
struct sigaction sigterm_action = { .sa_handler = handle_sigterm };
1305
/* Lower any group privileges we might have, just to be safe */
1309
perror_plus("setgid");
1312
/* Lower user privileges (temporarily) */
1316
perror_plus("seteuid");
1324
920
struct argp_option options[] = {
1325
921
{ .name = "debug", .key = 128,
1402
984
mc.priority = arg;
1404
986
case 131: /* --delay */
1406
delay = strtof(arg, &tmp);
1407
if(errno != 0 or tmp == arg or *tmp != '\0'){
1408
argp_error(state, "Bad delay");
1410
case 132: /* --retry */
1412
retry_interval = strtod(arg, &tmp);
1413
if(errno != 0 or tmp == arg or *tmp != '\0'
1414
or (retry_interval * 1000) > INT_MAX){
1415
argp_error(state, "Bad retry interval");
987
ret = sscanf(arg, "%lf%n", &delay, &numchars);
988
if(ret < 1 or arg[numchars] != '\0'){
989
fprintf(stderr, "Bad delay\n");
1419
* These reproduce what we would get without ARGP_NO_HELP
1421
case '?': /* --help */
1422
argp_state_help(state, state->out_stream,
1423
(ARGP_HELP_STD_HELP | ARGP_HELP_EXIT_ERR)
1424
& ~(unsigned int)ARGP_HELP_EXIT_OK);
1425
case -3: /* --usage */
1426
argp_state_help(state, state->out_stream,
1427
ARGP_HELP_USAGE | ARGP_HELP_EXIT_ERR);
1428
case 'V': /* --version */
1429
fprintf(state->out_stream, "%s\n", argp_program_version);
1430
exit(argp_err_exit_status);
1433
998
return ARGP_ERR_UNKNOWN;
1438
1003
struct argp argp = { .options = options, .parser = parse_opt,
1439
1004
.args_doc = "",
1440
1005
.doc = "Mandos client -- Get and decrypt"
1441
1006
" passwords from a Mandos server" };
1442
ret = argp_parse(&argp, argc, argv,
1443
ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);
1450
perror_plus("argp_parse");
1451
exitcode = EX_OSERR;
1454
exitcode = EX_USAGE;
1460
avahi_set_log_function(empty_log);
1463
if(interface[0] == '\0'){
1464
struct dirent **direntries;
1465
ret = scandir(sys_class_net, &direntries, good_interface,
1468
/* Pick the first good interface */
1469
interface = strdup(direntries[0]->d_name);
1471
fprintf(stderr, "Using interface \"%s\"\n", interface);
1473
if(interface == NULL){
1474
perror_plus("malloc");
1476
exitcode = EXIT_FAILURE;
1482
fprintf(stderr, "Could not find a network interface\n");
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");
1483
1010
exitcode = EXIT_FAILURE;
1488
/* Initialize Avahi early so avahi_simple_poll_quit() can be called
1489
from the signal handler */
1490
/* Initialize the pseudo-RNG for Avahi */
1491
srand((unsigned int) time(NULL));
1492
mc.simple_poll = avahi_simple_poll_new();
1493
if(mc.simple_poll == NULL){
1494
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1495
exitcode = EX_UNAVAILABLE;
1499
sigemptyset(&sigterm_action.sa_mask);
1500
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1502
perror_plus("sigaddset");
1503
exitcode = EX_OSERR;
1506
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1508
perror_plus("sigaddset");
1509
exitcode = EX_OSERR;
1512
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1514
perror_plus("sigaddset");
1515
exitcode = EX_OSERR;
1518
/* Need to check if the handler is SIG_IGN before handling:
1519
| [[info:libc:Initial Signal Actions]] |
1520
| [[info:libc:Basic Signal Handling]] |
1522
ret = sigaction(SIGINT, NULL, &old_sigterm_action);
1524
perror_plus("sigaction");
1527
if(old_sigterm_action.sa_handler != SIG_IGN){
1528
ret = sigaction(SIGINT, &sigterm_action, NULL);
1530
perror_plus("sigaction");
1531
exitcode = EX_OSERR;
1535
ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
1537
perror_plus("sigaction");
1540
if(old_sigterm_action.sa_handler != SIG_IGN){
1541
ret = sigaction(SIGHUP, &sigterm_action, NULL);
1543
perror_plus("sigaction");
1544
exitcode = EX_OSERR;
1548
ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
1550
perror_plus("sigaction");
1553
if(old_sigterm_action.sa_handler != SIG_IGN){
1554
ret = sigaction(SIGTERM, &sigterm_action, NULL);
1556
perror_plus("sigaction");
1557
exitcode = EX_OSERR;
1562
1015
/* If the interface is down, bring it up */
1563
if(strcmp(interface, "none") != 0){
1564
if_index = (AvahiIfIndex) if_nametoindex(interface);
1566
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1567
exitcode = EX_UNAVAILABLE;
1575
/* Re-raise priviliges */
1579
perror_plus("seteuid");
1016
if(interface[0] != '\0'){
1582
1017
#ifdef __linux__
1583
1018
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1584
messages about the network interface to mess up the prompt */
1019
messages to mess up the prompt */
1585
1020
ret = klogctl(8, NULL, 5);
1586
1021
bool restore_loglevel = true;
1588
1023
restore_loglevel = false;
1589
perror_plus("klogctl");
1591
1026
#endif /* __linux__ */
1593
1028
sd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP);
1595
perror_plus("socket");
1596
exitcode = EX_OSERR;
1031
exitcode = EXIT_FAILURE;
1597
1032
#ifdef __linux__
1598
1033
if(restore_loglevel){
1599
1034
ret = klogctl(7, NULL, 0);
1601
perror_plus("klogctl");
1604
1039
#endif /* __linux__ */
1605
/* Lower privileges */
1609
perror_plus("seteuid");
1613
1042
strcpy(network.ifr_name, interface);
1614
1043
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1616
perror_plus("ioctl SIOCGIFFLAGS");
1045
perror("ioctl SIOCGIFFLAGS");
1617
1046
#ifdef __linux__
1618
1047
if(restore_loglevel){
1619
1048
ret = klogctl(7, NULL, 0);
1621
perror_plus("klogctl");
1624
1053
#endif /* __linux__ */
1625
exitcode = EX_OSERR;
1626
/* Lower privileges */
1630
perror_plus("seteuid");
1054
exitcode = EXIT_FAILURE;
1634
1057
if((network.ifr_flags & IFF_UP) == 0){
1635
1058
network.ifr_flags |= IFF_UP;
1636
take_down_interface = true;
1637
1059
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1639
take_down_interface = false;
1640
perror_plus("ioctl SIOCSIFFLAGS +IFF_UP");
1641
exitcode = EX_OSERR;
1061
perror("ioctl SIOCSIFFLAGS");
1062
exitcode = EXIT_FAILURE;
1642
1063
#ifdef __linux__
1643
1064
if(restore_loglevel){
1644
1065
ret = klogctl(7, NULL, 0);
1646
perror_plus("klogctl");
1649
1070
#endif /* __linux__ */
1650
/* Lower privileges */
1654
perror_plus("seteuid");
1659
/* Sleep checking until interface is running.
1660
Check every 0.25s, up to total time of delay */
1074
/* sleep checking until interface is running */
1661
1075
for(int i=0; i < delay * 4; i++){
1662
1076
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1664
perror_plus("ioctl SIOCGIFFLAGS");
1078
perror("ioctl SIOCGIFFLAGS");
1665
1079
} else if(network.ifr_flags & IFF_RUNNING){
1668
1082
struct timespec sleeptime = { .tv_nsec = 250000000 };
1669
1083
ret = nanosleep(&sleeptime, NULL);
1670
1084
if(ret == -1 and errno != EINTR){
1671
perror_plus("nanosleep");
1085
perror("nanosleep");
1674
if(not take_down_interface){
1675
/* We won't need the socket anymore */
1676
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1678
perror_plus("close");
1088
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1681
1092
#ifdef __linux__
1682
1093
if(restore_loglevel){
1683
1094
/* Restores kernel loglevel to default */
1684
1095
ret = klogctl(7, NULL, 0);
1686
perror_plus("klogctl");
1689
1100
#endif /* __linux__ */
1690
/* Lower privileges */
1692
if(take_down_interface){
1693
/* Lower privileges */
1696
perror_plus("seteuid");
1699
/* Lower privileges permanently */
1702
perror_plus("setuid");
1711
1117
ret = init_gnutls_global(pubkey, seckey);
1713
1119
fprintf(stderr, "init_gnutls_global failed\n");
1714
exitcode = EX_UNAVAILABLE;
1120
exitcode = EXIT_FAILURE;
1717
1123
gnutls_initialized = true;
1724
1126
if(mkdtemp(tempdir) == NULL){
1725
perror_plus("mkdtemp");
1728
1130
tempdir_created = true;
1734
1132
if(not init_gpgme(pubkey, seckey, tempdir)){
1735
1133
fprintf(stderr, "init_gpgme failed\n");
1736
exitcode = EX_UNAVAILABLE;
1134
exitcode = EXIT_FAILURE;
1739
1137
gpgme_initialized = true;
1140
if(interface[0] != '\0'){
1141
if_index = (AvahiIfIndex) if_nametoindex(interface);
1143
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1144
exitcode = EXIT_FAILURE;
1746
1149
if(connect_to != NULL){
1827
1219
if(mc.server == NULL){
1828
1220
fprintf(stderr, "Failed to create Avahi server: %s\n",
1829
1221
avahi_strerror(error));
1830
exitcode = EX_UNAVAILABLE;
1222
exitcode = EXIT_FAILURE;
1838
1226
/* Create the Avahi service browser */
1839
1227
sb = avahi_s_service_browser_new(mc.server, if_index,
1840
AVAHI_PROTO_UNSPEC, "_mandos._tcp",
1228
AVAHI_PROTO_INET6, "_mandos._tcp",
1841
1229
NULL, 0, browse_callback, NULL);
1842
1230
if(sb == NULL){
1843
1231
fprintf(stderr, "Failed to create service browser: %s\n",
1844
1232
avahi_strerror(avahi_server_errno(mc.server)));
1845
exitcode = EX_UNAVAILABLE;
1233
exitcode = EXIT_FAILURE;
1237
sigemptyset(&sigterm_action.sa_mask);
1238
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1240
perror("sigaddset");
1241
exitcode = EXIT_FAILURE;
1244
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1246
perror("sigaddset");
1247
exitcode = EXIT_FAILURE;
1250
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1252
perror("sigaddset");
1253
exitcode = EXIT_FAILURE;
1256
ret = sigaction(SIGTERM, &sigterm_action, &old_sigterm_action);
1258
perror("sigaction");
1259
exitcode = EXIT_FAILURE;
1853
1263
/* Run the main loop */
1856
1266
fprintf(stderr, "Starting Avahi loop search\n");
1859
ret = avahi_loop_with_timeout(mc.simple_poll,
1860
(int)(retry_interval * 1000));
1862
fprintf(stderr, "avahi_loop_with_timeout exited %s\n",
1863
(ret == 0) ? "successfully" : "with error");
1269
avahi_simple_poll_loop(mc.simple_poll);
1888
1293
if(gpgme_initialized){
1889
1294
gpgme_release(mc.ctx);
1892
/* Cleans up the circular linked list of Mandos servers the client
1894
if(mc.current_server != NULL){
1895
mc.current_server->prev->next = NULL;
1896
while(mc.current_server != NULL){
1897
server *next = mc.current_server->next;
1898
free(mc.current_server);
1899
mc.current_server = next;
1903
/* Take down the network interface */
1904
if(take_down_interface){
1905
/* Re-raise priviliges */
1909
perror_plus("seteuid");
1912
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1914
perror_plus("ioctl SIOCGIFFLAGS");
1915
} else if(network.ifr_flags & IFF_UP) {
1916
network.ifr_flags &= ~(short)IFF_UP; /* clear flag */
1917
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1919
perror_plus("ioctl SIOCSIFFLAGS -IFF_UP");
1922
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1924
perror_plus("close");
1926
/* Lower privileges permanently */
1930
perror_plus("setuid");
1935
/* Removes the GPGME temp directory and all files inside */
1297
/* Removes the temp directory used by GPGME */
1936
1298
if(tempdir_created){
1937
struct dirent **direntries = NULL;
1938
struct dirent *direntry = NULL;
1939
ret = scandir(tempdir, &direntries, notdotentries, alphasort);
1941
for(int i = 0; i < ret; i++){
1942
direntry = direntries[i];
1300
struct dirent *direntry;
1301
d = opendir(tempdir);
1303
if(errno != ENOENT){
1308
direntry = readdir(d);
1309
if(direntry == NULL){
1312
/* Skip "." and ".." */
1313
if(direntry->d_name[0] == '.'
1314
and (direntry->d_name[1] == '\0'
1315
or (direntry->d_name[1] == '.'
1316
and direntry->d_name[2] == '\0'))){
1943
1319
char *fullname = NULL;
1944
1320
ret = asprintf(&fullname, "%s/%s", tempdir,
1945
1321
direntry->d_name);
1947
perror_plus("asprintf");
1950
1326
ret = remove(fullname);