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
43
#include <stdlib.h> /* free(), EXIT_SUCCESS, EXIT_FAILURE,
47
srand(), strtof(), abort() */
48
#include <stdbool.h> /* bool, false, true */
45
#include <stdbool.h> /* bool, true */
49
46
#include <string.h> /* memset(), strcmp(), strlen(),
50
47
strerror(), asprintf(), strcpy() */
51
#include <sys/ioctl.h> /* ioctl */
48
#include <sys/ioctl.h> /* ioctl */
52
49
#include <sys/types.h> /* socket(), inet_pton(), sockaddr,
53
50
sockaddr_in6, PF_INET6,
54
SOCK_STREAM, uid_t, gid_t, open(),
51
SOCK_STREAM, INET6_ADDRSTRLEN,
52
uid_t, gid_t, open(), opendir(),
56
54
#include <sys/stat.h> /* open() */
57
55
#include <sys/socket.h> /* socket(), struct sockaddr_in6,
58
inet_pton(), connect() */
56
struct in6_addr, inet_pton(),
59
58
#include <fcntl.h> /* open() */
60
59
#include <dirent.h> /* opendir(), struct dirent, readdir()
62
#include <inttypes.h> /* PRIu16, PRIdMAX, intmax_t,
61
#include <inttypes.h> /* PRIu16, intmax_t, SCNdMAX */
64
62
#include <assert.h> /* assert() */
65
63
#include <errno.h> /* perror(), errno */
66
64
#include <time.h> /* nanosleep(), time() */
67
65
#include <net/if.h> /* ioctl, ifreq, SIOCGIFFLAGS, IFF_UP,
68
66
SIOCSIFFLAGS, if_indextoname(),
69
67
if_nametoindex(), IF_NAMESIZE */
70
#include <netinet/in.h> /* IN6_IS_ADDR_LINKLOCAL,
71
INET_ADDRSTRLEN, INET6_ADDRSTRLEN
68
#include <netinet/in.h>
73
69
#include <unistd.h> /* close(), SEEK_SET, off_t, write(),
74
getuid(), getgid(), seteuid(),
70
getuid(), getgid(), setuid(),
76
72
#include <arpa/inet.h> /* inet_pton(), htons */
77
#include <iso646.h> /* not, or, and */
73
#include <iso646.h> /* not, and, or */
78
74
#include <argp.h> /* struct argp_option, error_t, struct
79
75
argp_state, struct argp,
80
76
argp_parse(), ARGP_KEY_ARG,
81
77
ARGP_KEY_END, ARGP_ERR_UNKNOWN */
82
#include <signal.h> /* sigemptyset(), sigaddset(),
83
sigaction(), SIGTERM, sig_atomic_t,
87
79
#include <sys/klog.h> /* klogctl() */
88
#endif /* __linux__ */
91
83
/* All Avahi types, constants and functions
140
130
} mandos_context;
142
/* global context so signal handler can reach it*/
143
mandos_context mc = { .simple_poll = NULL, .server = NULL,
144
.dh_bits = 1024, .priority = "SECURE256"
145
":!CTYPE-X.509:+CTYPE-OPENPGP" };
147
sig_atomic_t quit_now = 0;
148
int signal_received = 0;
151
* Make additional room in "buffer" for at least BUFFER_SIZE more
152
* bytes. "buffer_capacity" is how much is currently allocated,
133
* Make room in "buffer" for at least BUFFER_SIZE additional bytes.
134
* "buffer_capacity" is how much is currently allocated,
153
135
* "buffer_length" is how much is already used.
155
size_t incbuffer(char **buffer, size_t buffer_length,
137
size_t adjustbuffer(char **buffer, size_t buffer_length,
156
138
size_t buffer_capacity){
157
139
if(buffer_length + BUFFER_SIZE > buffer_capacity){
158
140
*buffer = realloc(*buffer, buffer_capacity + BUFFER_SIZE);
315
298
gpgme_recipient_t recipient;
316
299
recipient = result->recipients;
317
while(recipient != NULL){
318
fprintf(stderr, "Public key algorithm: %s\n",
319
gpgme_pubkey_algo_name(recipient->pubkey_algo));
320
fprintf(stderr, "Key ID: %s\n", recipient->keyid);
321
fprintf(stderr, "Secret key available: %s\n",
322
recipient->status == GPG_ERR_NO_SECKEY
324
recipient = recipient->next;
301
while(recipient != NULL){
302
fprintf(stderr, "Public key algorithm: %s\n",
303
gpgme_pubkey_algo_name(recipient->pubkey_algo));
304
fprintf(stderr, "Key ID: %s\n", recipient->keyid);
305
fprintf(stderr, "Secret key available: %s\n",
306
recipient->status == GPG_ERR_NO_SECKEY
308
recipient = recipient->next;
453
439
/* GnuTLS server initialization */
454
ret = gnutls_dh_params_init(&mc.dh_params);
440
ret = gnutls_dh_params_init(&mc->dh_params);
455
441
if(ret != GNUTLS_E_SUCCESS){
456
442
fprintf(stderr, "Error in GnuTLS DH parameter initialization:"
457
443
" %s\n", safer_gnutls_strerror(ret));
460
ret = gnutls_dh_params_generate2(mc.dh_params, mc.dh_bits);
446
ret = gnutls_dh_params_generate2(mc->dh_params, mc->dh_bits);
461
447
if(ret != GNUTLS_E_SUCCESS){
462
448
fprintf(stderr, "Error in GnuTLS prime generation: %s\n",
463
449
safer_gnutls_strerror(ret));
467
gnutls_certificate_set_dh_params(mc.cred, mc.dh_params);
453
gnutls_certificate_set_dh_params(mc->cred, mc->dh_params);
473
gnutls_certificate_free_credentials(mc.cred);
459
gnutls_certificate_free_credentials(mc->cred);
474
460
gnutls_global_deinit();
475
gnutls_dh_params_deinit(mc.dh_params);
461
gnutls_dh_params_deinit(mc->dh_params);
479
static int init_gnutls_session(gnutls_session_t *session){
465
static int init_gnutls_session(mandos_context *mc,
466
gnutls_session_t *session){
481
468
/* GnuTLS session creation */
483
ret = gnutls_init(session, GNUTLS_SERVER);
487
} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
469
ret = gnutls_init(session, GNUTLS_SERVER);
488
470
if(ret != GNUTLS_E_SUCCESS){
489
471
fprintf(stderr, "Error in GnuTLS session initialization: %s\n",
490
472
safer_gnutls_strerror(ret));
538
509
/* Called when a Mandos server is found */
539
510
static int start_mandos_communication(const char *ip, uint16_t port,
540
511
AvahiIfIndex if_index,
542
int ret, tcp_sd = -1;
545
struct sockaddr_in in;
546
struct sockaddr_in6 in6;
515
union { struct sockaddr in; struct sockaddr_in6 in6; } to;
548
516
char *buffer = NULL;
549
char *decrypted_buffer = NULL;
517
char *decrypted_buffer;
550
518
size_t buffer_length = 0;
551
519
size_t buffer_capacity = 0;
520
ssize_t decrypted_buffer_size;
523
char interface[IF_NAMESIZE];
554
524
gnutls_session_t session;
555
int pf; /* Protocol family */
569
fprintf(stderr, "Bad address family: %d\n", af);
573
ret = init_gnutls_session(&session);
526
ret = init_gnutls_session(mc, &session);
579
fprintf(stderr, "Setting up a TCP connection to %s, port %" PRIu16
532
fprintf(stderr, "Setting up a tcp connection to %s, port %" PRIu16
583
tcp_sd = socket(pf, SOCK_STREAM, 0);
536
tcp_sd = socket(PF_INET6, SOCK_STREAM, 0);
585
538
perror("socket");
543
if(if_indextoname((unsigned int)if_index, interface) == NULL){
544
perror("if_indextoname");
547
fprintf(stderr, "Binding to interface %s\n", interface);
593
550
memset(&to, 0, sizeof(to));
595
to.in6.sin6_family = (sa_family_t)af;
596
ret = inet_pton(af, ip, &to.in6.sin6_addr);
598
to.in.sin_family = (sa_family_t)af;
599
ret = inet_pton(af, ip, &to.in.sin_addr);
551
to.in6.sin6_family = AF_INET6;
552
/* It would be nice to have a way to detect if we were passed an
553
IPv4 address here. Now we assume an IPv6 address. */
554
ret = inet_pton(AF_INET6, ip, &to.in6.sin6_addr);
602
556
perror("inet_pton");
606
560
fprintf(stderr, "Bad address: %s\n", ip);
610
to.in6.sin6_port = htons(port); /* Spurious warnings from
612
-Wunreachable-code */
614
if(IN6_IS_ADDR_LINKLOCAL /* Spurious warnings from */
615
(&to.in6.sin6_addr)){ /* -Wstrict-aliasing=2 or lower and
617
if(if_index == AVAHI_IF_UNSPEC){
618
fprintf(stderr, "An IPv6 link-local address is incomplete"
619
" without a network interface\n");
622
/* Set the network interface number as scope */
623
to.in6.sin6_scope_id = (uint32_t)if_index;
626
to.in.sin_port = htons(port); /* Spurious warnings from
563
to.in6.sin6_port = htons(port); /* Spurious warnings from
628
565
-Wunreachable-code */
567
to.in6.sin6_scope_id = (uint32_t)if_index;
636
if(af == AF_INET6 and if_index != AVAHI_IF_UNSPEC){
637
char interface[IF_NAMESIZE];
638
if(if_indextoname((unsigned int)if_index, interface) == NULL){
639
perror("if_indextoname");
641
fprintf(stderr, "Connection to: %s%%%s, port %" PRIu16 "\n",
642
ip, interface, port);
645
fprintf(stderr, "Connection to: %s, port %" PRIu16 "\n", ip,
648
char addrstr[(INET_ADDRSTRLEN > INET6_ADDRSTRLEN) ?
649
INET_ADDRSTRLEN : INET6_ADDRSTRLEN] = "";
652
pcret = inet_ntop(af, &(to.in6.sin6_addr), addrstr,
655
pcret = inet_ntop(af, &(to.in.sin_addr), addrstr,
570
fprintf(stderr, "Connection to: %s, port %" PRIu16 "\n", ip,
572
char addrstr[INET6_ADDRSTRLEN] = "";
573
if(inet_ntop(to.in6.sin6_family, &(to.in6.sin6_addr), addrstr,
574
sizeof(addrstr)) == NULL){
659
575
perror("inet_ntop");
661
577
if(strcmp(addrstr, ip) != 0){
801
682
fprintf(stderr, "Closing TLS session\n");
809
ret = gnutls_bye(session, GNUTLS_SHUT_RDWR);
813
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
685
gnutls_bye(session, GNUTLS_SHUT_RDWR);
815
687
if(buffer_length > 0){
816
ssize_t decrypted_buffer_size;
817
decrypted_buffer_size = pgp_packet_decrypt(buffer,
688
decrypted_buffer_size = pgp_packet_decrypt(mc, buffer,
819
690
&decrypted_buffer);
820
691
if(decrypted_buffer_size >= 0){
823
693
while(written < (size_t) decrypted_buffer_size){
828
694
ret = (int)fwrite(decrypted_buffer + written, 1,
829
695
(size_t)decrypted_buffer_size - written,
943
801
the callback function is called the Avahi server will free the
944
802
resolver for us. */
946
if(avahi_s_service_resolver_new(mc.server, interface, protocol,
947
name, type, domain, protocol, 0,
948
resolve_callback, NULL) == NULL)
804
if(!(avahi_s_service_resolver_new(mc->server, interface,
805
protocol, name, type, domain,
806
AVAHI_PROTO_INET6, 0,
807
resolve_callback, mc)))
949
808
fprintf(stderr, "Avahi: Failed to resolve service '%s': %s\n",
950
name, avahi_strerror(avahi_server_errno(mc.server)));
809
name, avahi_strerror(avahi_server_errno(mc->server)));
953
812
case AVAHI_BROWSER_REMOVE:
965
/* stop main loop after sigterm has been called */
966
static void handle_sigterm(int sig){
971
signal_received = sig;
972
int old_errno = errno;
973
if(mc.simple_poll != NULL){
974
avahi_simple_poll_quit(mc.simple_poll);
980
* This function determines if a directory entry in /sys/class/net
981
* corresponds to an acceptable network device.
982
* (This function is passed to scandir(3) as a filter function.)
984
int good_interface(const struct dirent *if_entry){
986
char *flagname = NULL;
987
int ret = asprintf(&flagname, "%s/%s/flags", sys_class_net,
993
if(if_entry->d_name[0] == '.'){
996
int flags_fd = (int)TEMP_FAILURE_RETRY(open(flagname, O_RDONLY));
1001
typedef short ifreq_flags; /* ifreq.ifr_flags in netdevice(7) */
1002
/* read line from flags_fd */
1003
ssize_t to_read = (sizeof(ifreq_flags)*2)+3; /* "0x1003\n" */
1004
char *flagstring = malloc((size_t)to_read);
1005
if(flagstring == NULL){
1011
ssret = (ssize_t)TEMP_FAILURE_RETRY(read(flags_fd, flagstring,
1028
tmpmax = strtoimax(flagstring, &tmp, 0);
1029
if(errno != 0 or tmp == flagstring or (*tmp != '\0'
1030
and not (isspace(*tmp)))
1031
or tmpmax != (ifreq_flags)tmpmax){
1036
ifreq_flags flags = (ifreq_flags)tmpmax;
1037
/* Reject the loopback device */
1038
if(flags & IFF_LOOPBACK){
1041
/* Accept point-to-point devices only if connect_to is specified */
1042
if(connect_to != NULL and (flags & IFF_POINTOPOINT)){
1045
/* Otherwise, reject non-broadcast-capable devices */
1046
if(not (flags & IFF_BROADCAST)){
1049
/* Accept this device */
1053
824
int main(int argc, char *argv[]){
1054
825
AvahiSServiceBrowser *sb = NULL;
1057
828
intmax_t tmpmax;
1059
830
int exitcode = EXIT_SUCCESS;
1060
const char *interface = "";
831
const char *interface = "eth0";
1061
832
struct ifreq network;
1063
bool take_down_interface = false;
836
char *connect_to = NULL;
1066
837
char tempdir[] = "/tmp/mandosXXXXXX";
1067
838
bool tempdir_created = false;
1068
839
AvahiIfIndex if_index = AVAHI_IF_UNSPEC;
1069
840
const char *seckey = PATHDIR "/" SECKEY;
1070
841
const char *pubkey = PATHDIR "/" PUBKEY;
843
mandos_context mc = { .simple_poll = NULL, .server = NULL,
844
.dh_bits = 1024, .priority = "SECURE256"
845
":!CTYPE-X.509:+CTYPE-OPENPGP" };
1072
846
bool gnutls_initialized = false;
1073
847
bool gpgme_initialized = false;
1076
struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };
1077
struct sigaction sigterm_action = { .sa_handler = handle_sigterm };
1082
/* Lower any group privileges we might have, just to be safe */
1089
/* Lower user privileges (temporarily) */
1101
851
struct argp_option options[] = {
1199
avahi_set_log_function(empty_log);
1202
if(interface[0] == '\0'){
1203
struct dirent **direntries;
1204
ret = scandir(sys_class_net, &direntries, good_interface,
1207
/* Pick the first good interface */
1208
interface = strdup(direntries[0]->d_name);
1209
if(interface == NULL){
1212
exitcode = EXIT_FAILURE;
1218
fprintf(stderr, "Could not find a network interface\n");
1219
exitcode = EXIT_FAILURE;
1224
/* Initialize Avahi early so avahi_simple_poll_quit() can be called
1225
from the signal handler */
1226
/* Initialize the pseudo-RNG for Avahi */
1227
srand((unsigned int) time(NULL));
1228
mc.simple_poll = avahi_simple_poll_new();
1229
if(mc.simple_poll == NULL){
1230
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1231
exitcode = EXIT_FAILURE;
1235
sigemptyset(&sigterm_action.sa_mask);
1236
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1238
perror("sigaddset");
1239
exitcode = EXIT_FAILURE;
1242
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1244
perror("sigaddset");
1245
exitcode = EXIT_FAILURE;
1248
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1250
perror("sigaddset");
1251
exitcode = EXIT_FAILURE;
1254
/* Need to check if the handler is SIG_IGN before handling:
1255
| [[info:libc:Initial Signal Actions]] |
1256
| [[info:libc:Basic Signal Handling]] |
1258
ret = sigaction(SIGINT, NULL, &old_sigterm_action);
1260
perror("sigaction");
1261
return EXIT_FAILURE;
1263
if(old_sigterm_action.sa_handler != SIG_IGN){
1264
ret = sigaction(SIGINT, &sigterm_action, NULL);
1266
perror("sigaction");
1267
exitcode = EXIT_FAILURE;
1271
ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
1273
perror("sigaction");
1274
return EXIT_FAILURE;
1276
if(old_sigterm_action.sa_handler != SIG_IGN){
1277
ret = sigaction(SIGHUP, &sigterm_action, NULL);
1279
perror("sigaction");
1280
exitcode = EXIT_FAILURE;
1284
ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
1286
perror("sigaction");
1287
return EXIT_FAILURE;
1289
if(old_sigterm_action.sa_handler != SIG_IGN){
1290
ret = sigaction(SIGTERM, &sigterm_action, NULL);
1292
perror("sigaction");
1293
exitcode = EXIT_FAILURE;
1298
946
/* If the interface is down, bring it up */
1299
if(strcmp(interface, "none") != 0){
1300
if_index = (AvahiIfIndex) if_nametoindex(interface);
1302
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1303
exitcode = EXIT_FAILURE;
1311
/* Re-raise priviliges */
1318
948
#ifdef __linux__
1319
949
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1320
950
messages to mess up the prompt */
1321
951
ret = klogctl(8, NULL, 5);
1322
bool restore_loglevel = true;
1324
restore_loglevel = false;
1325
953
perror("klogctl");
1327
#endif /* __linux__ */
1329
957
sd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP);
1331
959
perror("socket");
1332
960
exitcode = EXIT_FAILURE;
1333
961
#ifdef __linux__
1334
if(restore_loglevel){
1335
ret = klogctl(7, NULL, 0);
1340
#endif /* __linux__ */
1341
/* Lower privileges */
962
ret = klogctl(7, NULL, 0);
1349
969
strcpy(network.ifr_name, interface);
1352
972
perror("ioctl SIOCGIFFLAGS");
1353
973
#ifdef __linux__
1354
if(restore_loglevel){
1355
ret = klogctl(7, NULL, 0);
974
ret = klogctl(7, NULL, 0);
1360
#endif /* __linux__ */
1361
979
exitcode = EXIT_FAILURE;
1362
/* Lower privileges */
1370
982
if((network.ifr_flags & IFF_UP) == 0){
1371
983
network.ifr_flags |= IFF_UP;
1372
take_down_interface = true;
1373
984
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1375
take_down_interface = false;
1376
986
perror("ioctl SIOCSIFFLAGS");
1377
987
exitcode = EXIT_FAILURE;
1378
988
#ifdef __linux__
1379
if(restore_loglevel){
1380
ret = klogctl(7, NULL, 0);
1385
#endif /* __linux__ */
1386
/* Lower privileges */
989
ret = klogctl(7, NULL, 0);
1406
1008
perror("nanosleep");
1409
if(not take_down_interface){
1410
/* We won't need the socket anymore */
1411
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1011
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1416
1015
#ifdef __linux__
1417
if(restore_loglevel){
1418
/* Restores kernel loglevel to default */
1419
ret = klogctl(7, NULL, 0);
1424
#endif /* __linux__ */
1425
/* Lower privileges */
1427
if(take_down_interface){
1428
/* Lower privileges */
1434
/* Lower privileges permanently */
1446
ret = init_gnutls_global(pubkey, seckey);
1016
/* Restores kernel loglevel to default */
1017
ret = klogctl(7, NULL, 0);
1037
ret = init_gnutls_global(&mc, pubkey, seckey);
1448
1039
fprintf(stderr, "init_gnutls_global failed\n");
1449
1040
exitcode = EXIT_FAILURE;
1488
1073
exitcode = EXIT_FAILURE;
1498
tmpmax = strtoimax(address+1, &tmp, 10);
1499
if(errno != 0 or tmp == address+1 or *tmp != '\0'
1500
or tmpmax != (uint16_t)tmpmax){
1077
ret = sscanf(address+1, "%" SCNdMAX "%n", &tmpmax, &numchars);
1078
if(ret < 1 or tmpmax != (uint16_t)tmpmax
1079
or address[numchars+1] != '\0'){
1501
1080
fprintf(stderr, "Bad port number\n");
1502
1081
exitcode = EXIT_FAILURE;
1510
1084
port = (uint16_t)tmpmax;
1511
1085
*address = '\0';
1512
1086
address = connect_to;
1513
/* Colon in address indicates IPv6 */
1515
if(strchr(address, ':') != NULL){
1525
ret = start_mandos_communication(address, port, if_index, af);
1087
ret = start_mandos_communication(address, port, if_index, &mc);
1527
1089
exitcode = EXIT_FAILURE;