32
32
/* Needed by GPGME, specifically gpgme_data_seek() */
33
#ifndef _LARGEFILE_SOURCE
34
33
#define _LARGEFILE_SOURCE
36
#ifndef _FILE_OFFSET_BITS
37
34
#define _FILE_OFFSET_BITS 64
40
36
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), asprintf() */
42
38
#include <stdio.h> /* fprintf(), stderr, fwrite(),
43
stdout, ferror(), remove() */
39
stdout, ferror(), sscanf(),
44
41
#include <stdint.h> /* uint16_t, uint32_t */
45
42
#include <stddef.h> /* NULL, size_t, ssize_t */
46
#include <stdlib.h> /* free(), EXIT_SUCCESS, srand(),
43
#include <stdlib.h> /* free(), EXIT_SUCCESS, EXIT_FAILURE,
48
45
#include <stdbool.h> /* bool, false, true */
49
46
#include <string.h> /* memset(), strcmp(), strlen(),
50
47
strerror(), asprintf(), strcpy() */
59
56
#include <fcntl.h> /* open() */
60
57
#include <dirent.h> /* opendir(), struct dirent, readdir()
62
#include <inttypes.h> /* PRIu16, PRIdMAX, intmax_t,
59
#include <inttypes.h> /* PRIu16, intmax_t, SCNdMAX */
64
60
#include <assert.h> /* assert() */
65
#include <errno.h> /* perror(), errno,
66
program_invocation_short_name */
67
#include <time.h> /* nanosleep(), time(), sleep() */
61
#include <errno.h> /* perror(), errno */
62
#include <time.h> /* nanosleep(), time() */
68
63
#include <net/if.h> /* ioctl, ifreq, SIOCGIFFLAGS, IFF_UP,
69
64
SIOCSIFFLAGS, if_indextoname(),
70
65
if_nametoindex(), IF_NAMESIZE */
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){
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){
1078
signal_received = sig;
1079
885
int old_errno = errno;
1080
/* set main loop to exit */
1081
886
if(mc.simple_poll != NULL){
1082
887
avahi_simple_poll_quit(mc.simple_poll);
1084
889
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
892
int main(int argc, char *argv[]){
1275
893
AvahiSServiceBrowser *sb = NULL;
1278
896
intmax_t tmpmax;
1280
898
int exitcode = EXIT_SUCCESS;
1281
const char *interface = "";
899
const char *interface = "eth0";
1282
900
struct ifreq network;
1284
bool take_down_interface = false;
904
char *connect_to = NULL;
1287
905
char tempdir[] = "/tmp/mandosXXXXXX";
1288
906
bool tempdir_created = false;
1289
907
AvahiIfIndex if_index = AVAHI_IF_UNSPEC;
1290
908
const char *seckey = PATHDIR "/" SECKEY;
1291
909
const char *pubkey = PATHDIR "/" PUBKEY;
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" };
1293
915
bool gnutls_initialized = false;
1294
916
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 };
919
struct sigaction old_sigterm_action;
1300
920
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
923
struct argp_option options[] = {
1325
924
{ .name = "debug", .key = 128,
1402
987
mc.priority = arg;
1404
989
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");
990
ret = sscanf(arg, "%lf%n", &delay, &numchars);
991
if(ret < 1 or arg[numchars] != '\0'){
992
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
1001
return ARGP_ERR_UNKNOWN;
1438
1006
struct argp argp = { .options = options, .parser = parse_opt,
1439
1007
.args_doc = "",
1440
1008
.doc = "Mandos client -- Get and decrypt"
1441
1009
" 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
/* Work around Debian bug #633582:
1461
<http://bugs.debian.org/633582> */
1464
/* Re-raise priviliges */
1468
perror_plus("seteuid");
1471
int seckey_fd = open(PATHDIR "/" SECKEY, O_RDONLY);
1472
if(seckey_fd == -1){
1473
perror_plus("open");
1475
ret = (int)TEMP_FAILURE_RETRY(fstat(seckey_fd, &st));
1477
perror_plus("fstat");
1479
if(S_ISREG(st.st_mode) and st.st_uid == 0 and st.st_gid == 0){
1480
ret = fchown(seckey_fd, uid, gid);
1482
perror_plus("fchown");
1486
TEMP_FAILURE_RETRY(close(seckey_fd));
1489
int pubkey_fd = open(PATHDIR "/" PUBKEY, O_RDONLY);
1490
if(pubkey_fd == -1){
1491
perror_plus("open");
1493
ret = (int)TEMP_FAILURE_RETRY(fstat(pubkey_fd, &st));
1495
perror_plus("fstat");
1497
if(S_ISREG(st.st_mode) and st.st_uid == 0 and st.st_gid == 0){
1498
ret = fchown(pubkey_fd, uid, gid);
1500
perror_plus("fchown");
1504
TEMP_FAILURE_RETRY(close(pubkey_fd));
1507
/* Lower privileges */
1511
perror_plus("seteuid");
1010
ret = argp_parse(&argp, argc, argv, 0, 0, NULL);
1011
if(ret == ARGP_ERR_UNKNOWN){
1012
fprintf(stderr, "Unknown error while parsing arguments\n");
1013
exitcode = EXIT_FAILURE;
1516
1019
avahi_set_log_function(empty_log);
1519
if(interface[0] == '\0'){
1520
struct dirent **direntries;
1521
ret = scandir(sys_class_net, &direntries, good_interface,
1524
/* Pick the first good interface */
1525
interface = strdup(direntries[0]->d_name);
1527
fprintf(stderr, "Using interface \"%s\"\n", interface);
1529
if(interface == NULL){
1530
perror_plus("malloc");
1532
exitcode = EXIT_FAILURE;
1538
fprintf(stderr, "Could not find a network interface\n");
1539
exitcode = EXIT_FAILURE;
1544
1022
/* Initialize Avahi early so avahi_simple_poll_quit() can be called
1545
1023
from the signal handler */
1548
1026
mc.simple_poll = avahi_simple_poll_new();
1549
1027
if(mc.simple_poll == NULL){
1550
1028
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1551
exitcode = EX_UNAVAILABLE;
1029
exitcode = EXIT_FAILURE;
1555
1033
sigemptyset(&sigterm_action.sa_mask);
1556
1034
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1558
perror_plus("sigaddset");
1559
exitcode = EX_OSERR;
1036
perror("sigaddset");
1037
exitcode = EXIT_FAILURE;
1562
1040
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1564
perror_plus("sigaddset");
1565
exitcode = EX_OSERR;
1042
perror("sigaddset");
1043
exitcode = EXIT_FAILURE;
1568
1046
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1570
perror_plus("sigaddset");
1571
exitcode = EX_OSERR;
1574
/* Need to check if the handler is SIG_IGN before handling:
1575
| [[info:libc:Initial Signal Actions]] |
1576
| [[info:libc:Basic Signal Handling]] |
1578
ret = sigaction(SIGINT, NULL, &old_sigterm_action);
1580
perror_plus("sigaction");
1583
if(old_sigterm_action.sa_handler != SIG_IGN){
1584
ret = sigaction(SIGINT, &sigterm_action, NULL);
1586
perror_plus("sigaction");
1587
exitcode = EX_OSERR;
1591
ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
1593
perror_plus("sigaction");
1596
if(old_sigterm_action.sa_handler != SIG_IGN){
1597
ret = sigaction(SIGHUP, &sigterm_action, NULL);
1599
perror_plus("sigaction");
1600
exitcode = EX_OSERR;
1604
ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
1606
perror_plus("sigaction");
1609
if(old_sigterm_action.sa_handler != SIG_IGN){
1610
ret = sigaction(SIGTERM, &sigterm_action, NULL);
1612
perror_plus("sigaction");
1613
exitcode = EX_OSERR;
1048
perror("sigaddset");
1049
exitcode = EXIT_FAILURE;
1052
ret = sigaction(SIGTERM, &sigterm_action, &old_sigterm_action);
1054
perror("sigaction");
1055
exitcode = EXIT_FAILURE;
1618
1059
/* If the interface is down, bring it up */
1619
if(strcmp(interface, "none") != 0){
1620
if_index = (AvahiIfIndex) if_nametoindex(interface);
1622
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1623
exitcode = EX_UNAVAILABLE;
1631
/* Re-raise priviliges */
1635
perror_plus("seteuid");
1060
if(interface[0] != '\0'){
1638
1061
#ifdef __linux__
1639
1062
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1640
messages about the network interface to mess up the prompt */
1063
messages to mess up the prompt */
1641
1064
ret = klogctl(8, NULL, 5);
1642
1065
bool restore_loglevel = true;
1644
1067
restore_loglevel = false;
1645
perror_plus("klogctl");
1647
1070
#endif /* __linux__ */
1649
1072
sd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP);
1651
perror_plus("socket");
1652
exitcode = EX_OSERR;
1075
exitcode = EXIT_FAILURE;
1653
1076
#ifdef __linux__
1654
1077
if(restore_loglevel){
1655
1078
ret = klogctl(7, NULL, 0);
1657
perror_plus("klogctl");
1660
1083
#endif /* __linux__ */
1661
/* Lower privileges */
1665
perror_plus("seteuid");
1669
1086
strcpy(network.ifr_name, interface);
1670
1087
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1672
perror_plus("ioctl SIOCGIFFLAGS");
1089
perror("ioctl SIOCGIFFLAGS");
1673
1090
#ifdef __linux__
1674
1091
if(restore_loglevel){
1675
1092
ret = klogctl(7, NULL, 0);
1677
perror_plus("klogctl");
1680
1097
#endif /* __linux__ */
1681
exitcode = EX_OSERR;
1682
/* Lower privileges */
1686
perror_plus("seteuid");
1098
exitcode = EXIT_FAILURE;
1690
1101
if((network.ifr_flags & IFF_UP) == 0){
1691
1102
network.ifr_flags |= IFF_UP;
1692
take_down_interface = true;
1693
1103
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1695
take_down_interface = false;
1696
perror_plus("ioctl SIOCSIFFLAGS +IFF_UP");
1697
exitcode = EX_OSERR;
1105
perror("ioctl SIOCSIFFLAGS");
1106
exitcode = EXIT_FAILURE;
1698
1107
#ifdef __linux__
1699
1108
if(restore_loglevel){
1700
1109
ret = klogctl(7, NULL, 0);
1702
perror_plus("klogctl");
1705
1114
#endif /* __linux__ */
1706
/* Lower privileges */
1710
perror_plus("seteuid");
1715
/* Sleep checking until interface is running.
1716
Check every 0.25s, up to total time of delay */
1118
/* sleep checking until interface is running */
1717
1119
for(int i=0; i < delay * 4; i++){
1718
1120
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1720
perror_plus("ioctl SIOCGIFFLAGS");
1122
perror("ioctl SIOCGIFFLAGS");
1721
1123
} else if(network.ifr_flags & IFF_RUNNING){
1724
1126
struct timespec sleeptime = { .tv_nsec = 250000000 };
1725
1127
ret = nanosleep(&sleeptime, NULL);
1726
1128
if(ret == -1 and errno != EINTR){
1727
perror_plus("nanosleep");
1129
perror("nanosleep");
1730
if(not take_down_interface){
1731
/* We won't need the socket anymore */
1732
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1734
perror_plus("close");
1132
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1737
1136
#ifdef __linux__
1738
1137
if(restore_loglevel){
1739
1138
/* Restores kernel loglevel to default */
1740
1139
ret = klogctl(7, NULL, 0);
1742
perror_plus("klogctl");
1745
1144
#endif /* __linux__ */
1746
/* Lower privileges */
1748
if(take_down_interface){
1749
/* Lower privileges */
1752
perror_plus("seteuid");
1755
/* Lower privileges permanently */
1758
perror_plus("setuid");
1767
1161
ret = init_gnutls_global(pubkey, seckey);
1769
1163
fprintf(stderr, "init_gnutls_global failed\n");
1770
exitcode = EX_UNAVAILABLE;
1164
exitcode = EXIT_FAILURE;
1773
1167
gnutls_initialized = true;
1780
1170
if(mkdtemp(tempdir) == NULL){
1781
perror_plus("mkdtemp");
1784
1174
tempdir_created = true;
1790
1176
if(not init_gpgme(pubkey, seckey, tempdir)){
1791
1177
fprintf(stderr, "init_gpgme failed\n");
1792
exitcode = EX_UNAVAILABLE;
1178
exitcode = EXIT_FAILURE;
1795
1181
gpgme_initialized = true;
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;
1802
1193
if(connect_to != NULL){
1944
1296
if(gpgme_initialized){
1945
1297
gpgme_release(mc.ctx);
1948
/* Cleans up the circular linked list of Mandos servers the client
1950
if(mc.current_server != NULL){
1951
mc.current_server->prev->next = NULL;
1952
while(mc.current_server != NULL){
1953
server *next = mc.current_server->next;
1954
free(mc.current_server);
1955
mc.current_server = next;
1959
/* Take down the network interface */
1960
if(take_down_interface){
1961
/* Re-raise priviliges */
1965
perror_plus("seteuid");
1968
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1970
perror_plus("ioctl SIOCGIFFLAGS");
1971
} else if(network.ifr_flags & IFF_UP) {
1972
network.ifr_flags &= ~(short)IFF_UP; /* clear flag */
1973
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1975
perror_plus("ioctl SIOCSIFFLAGS -IFF_UP");
1978
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1980
perror_plus("close");
1982
/* Lower privileges permanently */
1986
perror_plus("setuid");
1991
/* Removes the GPGME temp directory and all files inside */
1300
/* Removes the temp directory used by GPGME */
1992
1301
if(tempdir_created){
1993
struct dirent **direntries = NULL;
1994
struct dirent *direntry = NULL;
1995
ret = scandir(tempdir, &direntries, notdotentries, alphasort);
1997
for(int i = 0; i < ret; i++){
1998
direntry = direntries[i];
1303
struct dirent *direntry;
1304
d = opendir(tempdir);
1306
if(errno != ENOENT){
1311
direntry = readdir(d);
1312
if(direntry == NULL){
1315
/* Skip "." and ".." */
1316
if(direntry->d_name[0] == '.'
1317
and (direntry->d_name[1] == '\0'
1318
or (direntry->d_name[1] == '.'
1319
and direntry->d_name[2] == '\0'))){
1999
1322
char *fullname = NULL;
2000
1323
ret = asprintf(&fullname, "%s/%s", tempdir,
2001
1324
direntry->d_name);
2003
perror_plus("asprintf");
2006
1329
ret = remove(fullname);