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() */
38
42
#include <stdio.h> /* fprintf(), stderr, fwrite(),
39
stdout, ferror(), sscanf(),
43
stdout, ferror(), remove() */
41
44
#include <stdint.h> /* uint16_t, uint32_t */
42
45
#include <stddef.h> /* NULL, size_t, ssize_t */
43
#include <stdlib.h> /* free(), EXIT_SUCCESS, EXIT_FAILURE,
46
#include <stdlib.h> /* free(), EXIT_SUCCESS, srand(),
45
48
#include <stdbool.h> /* bool, false, true */
46
49
#include <string.h> /* memset(), strcmp(), strlen(),
47
50
strerror(), asprintf(), strcpy() */
56
59
#include <fcntl.h> /* open() */
57
60
#include <dirent.h> /* opendir(), struct dirent, readdir()
59
#include <inttypes.h> /* PRIu16, intmax_t, SCNdMAX */
62
#include <inttypes.h> /* PRIu16, PRIdMAX, intmax_t,
60
64
#include <assert.h> /* assert() */
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65
#include <errno.h> /* perror(), errno */
62
#include <time.h> /* nanosleep(), time() */
66
#include <time.h> /* nanosleep(), time(), sleep() */
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67
#include <net/if.h> /* ioctl, ifreq, SIOCGIFFLAGS, IFF_UP,
64
68
SIOCSIFFLAGS, if_indextoname(),
65
69
if_nametoindex(), IF_NAMESIZE */
67
71
INET_ADDRSTRLEN, INET6_ADDRSTRLEN
69
73
#include <unistd.h> /* close(), SEEK_SET, off_t, write(),
70
getuid(), getgid(), setuid(),
72
#include <arpa/inet.h> /* inet_pton(), htons */
74
getuid(), getgid(), seteuid(),
76
#include <arpa/inet.h> /* inet_pton(), htons, inet_ntop() */
73
77
#include <iso646.h> /* not, or, and */
74
78
#include <argp.h> /* struct argp_option, error_t, struct
75
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argp_state, struct argp,
76
80
argp_parse(), ARGP_KEY_ARG,
77
81
ARGP_KEY_END, ARGP_ERR_UNKNOWN */
78
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#include <signal.h> /* sigemptyset(), sigaddset(),
79
sigaction(), SIGTERM, sigaction,
83
sigaction(), SIGTERM, sig_atomic_t,
85
#include <sysexits.h> /* EX_OSERR, EX_USAGE, EX_UNAVAILABLE,
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EX_NOHOST, EX_IOERR, EX_PROTOCOL */
83
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#include <sys/klog.h> /* klogctl() */
306
317
gpgme_recipient_t recipient;
307
318
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;
319
while(recipient != NULL){
320
fprintf(stderr, "Public key algorithm: %s\n",
321
gpgme_pubkey_algo_name(recipient->pubkey_algo));
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fprintf(stderr, "Key ID: %s\n", recipient->keyid);
323
fprintf(stderr, "Secret key available: %s\n",
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recipient->status == GPG_ERR_NO_SECKEY
326
recipient = recipient->next;
557
586
tcp_sd = socket(pf, SOCK_STREAM, 0);
559
589
perror("socket");
563
599
memset(&to, 0, sizeof(to));
564
600
if(af == AF_INET6){
565
to.in6.sin6_family = (uint16_t)af;
601
to.in6.sin6_family = (sa_family_t)af;
566
602
ret = inet_pton(af, ip, &to.in6.sin6_addr);
567
603
} else { /* IPv4 */
568
604
to.in.sin_family = (sa_family_t)af;
569
605
ret = inet_pton(af, ip, &to.in.sin_addr);
572
609
perror("inet_pton");
576
615
fprintf(stderr, "Bad address: %s\n", ip);
579
619
if(af == AF_INET6){
580
620
to.in6.sin6_port = htons(port); /* Spurious warnings from
736
833
fprintf(stderr, "Closing TLS session\n");
739
gnutls_bye(session, GNUTLS_SHUT_RDWR);
842
ret = gnutls_bye(session, GNUTLS_SHUT_RDWR);
847
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
741
849
if(buffer_length > 0){
850
ssize_t decrypted_buffer_size;
742
851
decrypted_buffer_size = pgp_packet_decrypt(buffer,
744
853
&decrypted_buffer);
745
854
if(decrypted_buffer_size >= 0){
747
857
while(written < (size_t) decrypted_buffer_size){
748
863
ret = (int)fwrite(decrypted_buffer + written, 1,
749
864
(size_t)decrypted_buffer_size - written,
751
866
if(ret == 0 and ferror(stdout)){
753
869
fprintf(stderr, "Error writing encrypted data: %s\n",
754
870
strerror(errno));
759
875
written += (size_t)ret;
761
free(decrypted_buffer);
769
881
/* Shutdown procedure */
773
ret = (int)TEMP_FAILURE_RETRY(close(tcp_sd));
886
free(decrypted_buffer);
889
ret = (int)TEMP_FAILURE_RETRY(close(tcp_sd));
897
gnutls_deinit(session);
777
gnutls_deinit(session);
854
988
the callback function is called the Avahi server will free the
855
989
resolver for us. */
857
if(!(avahi_s_service_resolver_new(mc.server, interface,
858
protocol, name, type, domain,
859
AVAHI_PROTO_INET6, 0,
860
resolve_callback, NULL)))
991
if(avahi_s_service_resolver_new(mc.server, interface, protocol,
992
name, type, domain, protocol, 0,
993
resolve_callback, NULL) == NULL)
861
994
fprintf(stderr, "Avahi: Failed to resolve service '%s': %s\n",
862
995
name, avahi_strerror(avahi_server_errno(mc.server)));
889
1021
errno = old_errno;
1025
* This function determines if a directory entry in /sys/class/net
1026
* corresponds to an acceptable network device.
1027
* (This function is passed to scandir(3) as a filter function.)
1029
int good_interface(const struct dirent *if_entry){
1031
char *flagname = NULL;
1032
if(if_entry->d_name[0] == '.'){
1035
int ret = asprintf(&flagname, "%s/%s/flags", sys_class_net,
1041
int flags_fd = (int)TEMP_FAILURE_RETRY(open(flagname, O_RDONLY));
1048
typedef short ifreq_flags; /* ifreq.ifr_flags in netdevice(7) */
1049
/* read line from flags_fd */
1050
ssize_t to_read = 2+(sizeof(ifreq_flags)*2)+1; /* "0x1003\n" */
1051
char *flagstring = malloc((size_t)to_read+1); /* +1 for final \0 */
1052
flagstring[(size_t)to_read] = '\0';
1053
if(flagstring == NULL){
1059
ssret = (ssize_t)TEMP_FAILURE_RETRY(read(flags_fd, flagstring,
1076
tmpmax = strtoimax(flagstring, &tmp, 0);
1077
if(errno != 0 or tmp == flagstring or (*tmp != '\0'
1078
and not (isspace(*tmp)))
1079
or tmpmax != (ifreq_flags)tmpmax){
1081
fprintf(stderr, "Invalid flags \"%s\" for interface \"%s\"\n",
1082
flagstring, if_entry->d_name);
1088
ifreq_flags flags = (ifreq_flags)tmpmax;
1089
/* Reject the loopback device */
1090
if(flags & IFF_LOOPBACK){
1092
fprintf(stderr, "Rejecting loopback interface \"%s\"\n",
1097
/* Accept point-to-point devices only if connect_to is specified */
1098
if(connect_to != NULL and (flags & IFF_POINTOPOINT)){
1100
fprintf(stderr, "Accepting point-to-point interface \"%s\"\n",
1105
/* Otherwise, reject non-broadcast-capable devices */
1106
if(not (flags & IFF_BROADCAST)){
1108
fprintf(stderr, "Rejecting non-broadcast interface \"%s\"\n",
1113
/* Reject non-ARP interfaces (including dummy interfaces) */
1114
if(flags & IFF_NOARP){
1116
fprintf(stderr, "Rejecting non-ARP interface \"%s\"\n",
1121
/* Accept this device */
1123
fprintf(stderr, "Interface \"%s\" is acceptable\n",
892
1129
int main(int argc, char *argv[]){
893
1130
AvahiSServiceBrowser *sb = NULL;
896
1133
intmax_t tmpmax;
898
1135
int exitcode = EXIT_SUCCESS;
899
const char *interface = "eth0";
1136
const char *interface = "";
900
1137
struct ifreq network;
1139
bool take_down_interface = false;
904
char *connect_to = NULL;
905
1142
char tempdir[] = "/tmp/mandosXXXXXX";
906
1143
bool tempdir_created = false;
907
1144
AvahiIfIndex if_index = AVAHI_IF_UNSPEC;
908
1145
const char *seckey = PATHDIR "/" SECKEY;
909
1146
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" };
915
1148
bool gnutls_initialized = false;
916
1149
bool gpgme_initialized = false;
919
struct sigaction old_sigterm_action;
1152
struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };
920
1153
struct sigaction sigterm_action = { .sa_handler = handle_sigterm };
1158
/* Lower any group privileges we might have, just to be safe */
1165
/* Lower user privileges (temporarily) */
923
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struct argp_option options[] = {
924
1178
{ .name = "debug", .key = 128,
953
1207
.arg = "SECONDS",
954
1208
.doc = "Maximum delay to wait for interface startup",
1211
* These reproduce what we would get without ARGP_NO_HELP
1213
{ .name = "help", .key = '?',
1214
.doc = "Give this help list", .group = -1 },
1215
{ .name = "usage", .key = -3,
1216
.doc = "Give a short usage message", .group = -1 },
1217
{ .name = "version", .key = 'V',
1218
.doc = "Print program version", .group = -1 },
956
1219
{ .name = NULL }
959
1222
error_t parse_opt(int key, char *arg,
960
1223
struct argp_state *state){
962
1226
case 128: /* --debug */
977
1241
case 129: /* --dh-bits */
978
ret = sscanf(arg, "%" SCNdMAX "%n", &tmpmax, &numchars);
979
if(ret < 1 or tmpmax != (typeof(mc.dh_bits))tmpmax
980
or arg[numchars] != '\0'){
981
fprintf(stderr, "Bad number of DH bits\n");
1243
tmpmax = strtoimax(arg, &tmp, 10);
1244
if(errno != 0 or tmp == arg or *tmp != '\0'
1245
or tmpmax != (typeof(mc.dh_bits))tmpmax){
1246
argp_error(state, "Bad number of DH bits");
984
1248
mc.dh_bits = (typeof(mc.dh_bits))tmpmax;
987
1251
mc.priority = arg;
989
1253
case 131: /* --delay */
990
ret = sscanf(arg, "%lf%n", &delay, &numchars);
991
if(ret < 1 or arg[numchars] != '\0'){
992
fprintf(stderr, "Bad delay\n");
1255
delay = strtof(arg, &tmp);
1256
if(errno != 0 or tmp == arg or *tmp != '\0'){
1257
argp_error(state, "Bad delay");
1261
* These reproduce what we would get without ARGP_NO_HELP
1263
case '?': /* --help */
1264
argp_state_help(state, state->out_stream,
1265
(ARGP_HELP_STD_HELP | ARGP_HELP_EXIT_ERR)
1266
& ~(unsigned int)ARGP_HELP_EXIT_OK);
1267
case -3: /* --usage */
1268
argp_state_help(state, state->out_stream,
1269
ARGP_HELP_USAGE | ARGP_HELP_EXIT_ERR);
1270
case 'V': /* --version */
1271
fprintf(state->out_stream, "%s\n", argp_program_version);
1272
exit(argp_err_exit_status);
1001
1275
return ARGP_ERR_UNKNOWN;
1006
1280
struct argp argp = { .options = options, .parser = parse_opt,
1007
1281
.args_doc = "",
1008
1282
.doc = "Mandos client -- Get and decrypt"
1009
1283
" passwords from a Mandos server" };
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;
1284
ret = argp_parse(&argp, argc, argv,
1285
ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);
1292
perror("argp_parse");
1293
exitcode = EX_OSERR;
1296
exitcode = EX_USAGE;
1019
1302
avahi_set_log_function(empty_log);
1305
if(interface[0] == '\0'){
1306
struct dirent **direntries;
1307
ret = scandir(sys_class_net, &direntries, good_interface,
1310
/* Pick the first good interface */
1311
interface = strdup(direntries[0]->d_name);
1313
fprintf(stderr, "Using interface \"%s\"\n", interface);
1315
if(interface == NULL){
1318
exitcode = EXIT_FAILURE;
1324
fprintf(stderr, "Could not find a network interface\n");
1325
exitcode = EXIT_FAILURE;
1022
1330
/* Initialize Avahi early so avahi_simple_poll_quit() can be called
1023
1331
from the signal handler */
1034
1342
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1036
1344
perror("sigaddset");
1037
exitcode = EXIT_FAILURE;
1345
exitcode = EX_OSERR;
1040
1348
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1042
1350
perror("sigaddset");
1043
exitcode = EXIT_FAILURE;
1351
exitcode = EX_OSERR;
1046
1354
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1048
1356
perror("sigaddset");
1049
exitcode = EXIT_FAILURE;
1052
ret = sigaction(SIGTERM, &sigterm_action, &old_sigterm_action);
1054
perror("sigaction");
1055
exitcode = EXIT_FAILURE;
1357
exitcode = EX_OSERR;
1360
/* Need to check if the handler is SIG_IGN before handling:
1361
| [[info:libc:Initial Signal Actions]] |
1362
| [[info:libc:Basic Signal Handling]] |
1364
ret = sigaction(SIGINT, NULL, &old_sigterm_action);
1366
perror("sigaction");
1369
if(old_sigterm_action.sa_handler != SIG_IGN){
1370
ret = sigaction(SIGINT, &sigterm_action, NULL);
1372
perror("sigaction");
1373
exitcode = EX_OSERR;
1377
ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
1379
perror("sigaction");
1382
if(old_sigterm_action.sa_handler != SIG_IGN){
1383
ret = sigaction(SIGHUP, &sigterm_action, NULL);
1385
perror("sigaction");
1386
exitcode = EX_OSERR;
1390
ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
1392
perror("sigaction");
1395
if(old_sigterm_action.sa_handler != SIG_IGN){
1396
ret = sigaction(SIGTERM, &sigterm_action, NULL);
1398
perror("sigaction");
1399
exitcode = EX_OSERR;
1059
1404
/* If the interface is down, bring it up */
1060
if(interface[0] != '\0'){
1405
if(strcmp(interface, "none") != 0){
1406
if_index = (AvahiIfIndex) if_nametoindex(interface);
1408
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1409
exitcode = EX_UNAVAILABLE;
1417
/* Re-raise priviliges */
1061
1424
#ifdef __linux__
1062
1425
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1063
messages to mess up the prompt */
1426
messages about the network interface to mess up the prompt */
1064
1427
ret = klogctl(8, NULL, 5);
1065
1428
bool restore_loglevel = true;
1144
1530
#endif /* __linux__ */
1531
/* Lower privileges */
1533
if(take_down_interface){
1534
/* Lower privileges */
1540
/* Lower privileges permanently */
1161
1552
ret = init_gnutls_global(pubkey, seckey);
1163
1554
fprintf(stderr, "init_gnutls_global failed\n");
1164
exitcode = EXIT_FAILURE;
1555
exitcode = EX_UNAVAILABLE;
1167
1558
gnutls_initialized = true;
1565
tempdir_created = true;
1170
1566
if(mkdtemp(tempdir) == NULL){
1567
tempdir_created = false;
1171
1568
perror("mkdtemp");
1174
tempdir_created = true;
1176
1576
if(not init_gpgme(pubkey, seckey, tempdir)){
1177
1577
fprintf(stderr, "init_gpgme failed\n");
1178
exitcode = EXIT_FAILURE;
1578
exitcode = EX_UNAVAILABLE;
1181
1581
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;
1193
1588
if(connect_to != NULL){
1196
1591
char *address = strrchr(connect_to, ':');
1197
1592
if(address == NULL){
1198
1593
fprintf(stderr, "No colon in address\n");
1199
exitcode = EXIT_FAILURE;
1594
exitcode = EX_USAGE;
1203
ret = sscanf(address+1, "%" SCNdMAX "%n", &tmpmax, &numchars);
1204
if(ret < 1 or tmpmax != (uint16_t)tmpmax
1205
or address[numchars+1] != '\0'){
1604
tmpmax = strtoimax(address+1, &tmp, 10);
1605
if(errno != 0 or tmp == address+1 or *tmp != '\0'
1606
or tmpmax != (uint16_t)tmpmax){
1206
1607
fprintf(stderr, "Bad port number\n");
1207
exitcode = EXIT_FAILURE;
1608
exitcode = EX_USAGE;
1210
1616
port = (uint16_t)tmpmax;
1211
1617
*address = '\0';
1212
1618
address = connect_to;
1248
1669
if(mc.server == NULL){
1249
1670
fprintf(stderr, "Failed to create Avahi server: %s\n",
1250
1671
avahi_strerror(error));
1251
exitcode = EXIT_FAILURE;
1672
exitcode = EX_UNAVAILABLE;
1255
1680
/* Create the Avahi service browser */
1256
1681
sb = avahi_s_service_browser_new(mc.server, if_index,
1257
AVAHI_PROTO_INET6, "_mandos._tcp",
1682
AVAHI_PROTO_UNSPEC, "_mandos._tcp",
1258
1683
NULL, 0, browse_callback, NULL);
1259
1684
if(sb == NULL){
1260
1685
fprintf(stderr, "Failed to create service browser: %s\n",
1261
1686
avahi_strerror(avahi_server_errno(mc.server)));
1262
exitcode = EXIT_FAILURE;
1687
exitcode = EX_UNAVAILABLE;
1297
1726
gpgme_release(mc.ctx);
1729
/* Take down the network interface */
1730
if(take_down_interface){
1731
/* Re-raise priviliges */
1738
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1740
perror("ioctl SIOCGIFFLAGS");
1741
} else if(network.ifr_flags & IFF_UP) {
1742
network.ifr_flags &= ~(short)IFF_UP; /* clear flag */
1743
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1745
perror("ioctl SIOCSIFFLAGS -IFF_UP");
1748
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1752
/* Lower privileges permanently */
1300
1761
/* Removes the temp directory used by GPGME */
1301
1762
if(tempdir_created){