26
26
* along with this program. If not, see
27
27
* <http://www.gnu.org/licenses/>.
29
* Contact the authors at <mandos@fukt.bsnet.se>.
29
* Contact the authors at <mandos@recompile.se>.
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(),
41
#include <stdint.h> /* uint16_t, uint32_t */
43
stdout, ferror(), remove() */
44
#include <stdint.h> /* uint16_t, uint32_t, intptr_t */
42
45
#include <stddef.h> /* NULL, size_t, ssize_t */
43
#include <stdlib.h> /* free(), EXIT_SUCCESS, EXIT_FAILURE,
45
#include <stdbool.h> /* bool, true */
46
#include <stdlib.h> /* free(), EXIT_SUCCESS, srand(),
48
#include <stdbool.h> /* bool, false, true */
46
49
#include <string.h> /* memset(), strcmp(), strlen(),
47
50
strerror(), asprintf(), strcpy() */
48
#include <sys/ioctl.h> /* ioctl */
51
#include <sys/ioctl.h> /* ioctl */
49
52
#include <sys/types.h> /* socket(), inet_pton(), sockaddr,
50
53
sockaddr_in6, PF_INET6,
51
SOCK_STREAM, INET6_ADDRSTRLEN,
52
uid_t, gid_t, open(), opendir(),
54
#include <sys/stat.h> /* open() */
54
SOCK_STREAM, uid_t, gid_t, open(),
56
#include <sys/stat.h> /* open(), S_ISREG */
55
57
#include <sys/socket.h> /* socket(), struct sockaddr_in6,
56
struct in6_addr, inet_pton(),
58
inet_pton(), connect(),
58
60
#include <fcntl.h> /* open() */
59
61
#include <dirent.h> /* opendir(), struct dirent, readdir()
61
#include <inttypes.h> /* PRIu16, intmax_t, SCNdMAX */
62
#include <assert.h> /* assert() */
63
#include <errno.h> /* perror(), errno */
64
#include <time.h> /* nanosleep(), time() */
63
#include <inttypes.h> /* PRIu16, PRIdMAX, intmax_t,
65
#include <errno.h> /* perror(), errno,
66
program_invocation_short_name */
67
#include <time.h> /* nanosleep(), time(), sleep() */
65
68
#include <net/if.h> /* ioctl, ifreq, SIOCGIFFLAGS, IFF_UP,
66
69
SIOCSIFFLAGS, if_indextoname(),
67
70
if_nametoindex(), IF_NAMESIZE */
68
#include <netinet/in.h>
71
#include <netinet/in.h> /* IN6_IS_ADDR_LINKLOCAL,
72
INET_ADDRSTRLEN, INET6_ADDRSTRLEN
69
74
#include <unistd.h> /* close(), SEEK_SET, off_t, write(),
70
getuid(), getgid(), setuid(),
72
#include <arpa/inet.h> /* inet_pton(), htons */
73
#include <iso646.h> /* not, and, or */
75
getuid(), getgid(), seteuid(),
76
setgid(), pause(), _exit() */
77
#include <arpa/inet.h> /* inet_pton(), htons() */
78
#include <iso646.h> /* not, or, and */
74
79
#include <argp.h> /* struct argp_option, error_t, struct
75
80
argp_state, struct argp,
76
81
argp_parse(), ARGP_KEY_ARG,
77
82
ARGP_KEY_END, ARGP_ERR_UNKNOWN */
83
#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 */
88
#include <sys/wait.h> /* waitpid(), WIFEXITED(),
89
WEXITSTATUS(), WTERMSIG() */
90
#include <grp.h> /* setgroups() */
91
#include <argz.h> /* argz_add_sep(), argz_next(),
92
argz_delete(), argz_append(),
93
argz_stringify(), argz_add(),
95
#include <netdb.h> /* getnameinfo(), NI_NUMERICHOST,
96
EAI_SYSTEM, gai_strerror() */
79
99
#include <sys/klog.h> /* klogctl() */
100
#endif /* __linux__ */
83
103
/* All Avahi types, constants and functions
112
132
#define PATHDIR "/conf/conf.d/mandos"
113
133
#define SECKEY "seckey.txt"
114
134
#define PUBKEY "pubkey.txt"
135
#define HOOKDIR "/lib/mandos/network-hooks.d"
116
137
bool debug = false;
117
138
static const char mandos_protocol_version[] = "1";
118
139
const char *argp_program_version = "mandos-client " VERSION;
119
const char *argp_program_bug_address = "<mandos@fukt.bsnet.se>";
140
const char *argp_program_bug_address = "<mandos@recompile.se>";
141
static const char sys_class_net[] = "/sys/class/net";
142
char *connect_to = NULL;
143
const char *hookdir = HOOKDIR;
147
/* Doubly linked list that need to be circularly linked when used */
148
typedef struct server{
151
AvahiIfIndex if_index;
153
struct timespec last_seen;
121
158
/* Used for passing in values through the Avahi callback functions */
123
AvahiSimplePoll *simple_poll;
124
160
AvahiServer *server;
125
161
gnutls_certificate_credentials_t cred;
126
162
unsigned int dh_bits;
127
163
gnutls_dh_params_t dh_params;
128
164
const char *priority;
166
server *current_server;
168
size_t interfaces_size;
130
169
} mandos_context;
171
/* global so signal handler can reach it*/
172
AvahiSimplePoll *simple_poll;
174
sig_atomic_t quit_now = 0;
175
int signal_received = 0;
177
/* Function to use when printing errors */
178
void perror_plus(const char *print_text){
180
fprintf(stderr, "Mandos plugin %s: ",
181
program_invocation_short_name);
186
__attribute__((format (gnu_printf, 2, 3)))
187
int fprintf_plus(FILE *stream, const char *format, ...){
189
va_start (ap, format);
191
TEMP_FAILURE_RETRY(fprintf(stream, "Mandos plugin %s: ",
192
program_invocation_short_name));
193
return (int)TEMP_FAILURE_RETRY(vfprintf(stream, format, ap));
133
* Make room in "buffer" for at least BUFFER_SIZE additional bytes.
134
* "buffer_capacity" is how much is currently allocated,
197
* Make additional room in "buffer" for at least BUFFER_SIZE more
198
* bytes. "buffer_capacity" is how much is currently allocated,
135
199
* "buffer_length" is how much is already used.
137
size_t adjustbuffer(char **buffer, size_t buffer_length,
138
size_t buffer_capacity){
201
size_t incbuffer(char **buffer, size_t buffer_length,
202
size_t buffer_capacity){
139
203
if(buffer_length + BUFFER_SIZE > buffer_capacity){
140
*buffer = realloc(*buffer, buffer_capacity + BUFFER_SIZE);
204
char *new_buf = realloc(*buffer, buffer_capacity + BUFFER_SIZE);
206
int old_errno = errno;
144
213
buffer_capacity += BUFFER_SIZE;
146
215
return buffer_capacity;
218
/* Add server to set of servers to retry periodically */
219
bool add_server(const char *ip, in_port_t port, AvahiIfIndex if_index,
220
int af, server **current_server){
222
server *new_server = malloc(sizeof(server));
223
if(new_server == NULL){
224
perror_plus("malloc");
227
*new_server = (server){ .ip = strdup(ip),
229
.if_index = if_index,
231
if(new_server->ip == NULL){
232
perror_plus("strdup");
235
ret = clock_gettime(CLOCK_MONOTONIC, &(new_server->last_seen));
237
perror_plus("clock_gettime");
240
/* Special case of first server */
241
if(*current_server == NULL){
242
new_server->next = new_server;
243
new_server->prev = new_server;
244
*current_server = new_server;
245
/* Place the new server last in the list */
247
new_server->next = *current_server;
248
new_server->prev = (*current_server)->prev;
249
new_server->prev->next = new_server;
250
(*current_server)->prev = new_server;
150
256
* Initialize GPGME.
152
static bool init_gpgme(mandos_context *mc, const char *seckey,
153
const char *pubkey, const char *tempdir){
258
static bool init_gpgme(const char *seckey, const char *pubkey,
259
const char *tempdir, mandos_context *mc){
155
260
gpgme_error_t rc;
156
261
gpgme_engine_info_t engine_info;
160
264
* Helper function to insert pub and seckey to the engine keyring.
162
266
bool import_key(const char *filename){
164
269
gpgme_data_t pgp_data;
166
271
fd = (int)TEMP_FAILURE_RETRY(open(filename, O_RDONLY));
172
277
rc = gpgme_data_new_from_fd(&pgp_data, fd);
173
278
if(rc != GPG_ERR_NO_ERROR){
174
fprintf(stderr, "bad gpgme_data_new_from_fd: %s: %s\n",
175
gpgme_strsource(rc), gpgme_strerror(rc));
279
fprintf_plus(stderr, "bad gpgme_data_new_from_fd: %s: %s\n",
280
gpgme_strsource(rc), gpgme_strerror(rc));
179
284
rc = gpgme_op_import(mc->ctx, pgp_data);
180
285
if(rc != GPG_ERR_NO_ERROR){
181
fprintf(stderr, "bad gpgme_op_import: %s: %s\n",
182
gpgme_strsource(rc), gpgme_strerror(rc));
286
fprintf_plus(stderr, "bad gpgme_op_import: %s: %s\n",
287
gpgme_strsource(rc), gpgme_strerror(rc));
186
291
ret = (int)TEMP_FAILURE_RETRY(close(fd));
293
perror_plus("close");
190
295
gpgme_data_release(pgp_data);
195
fprintf(stderr, "Initialize gpgme\n");
300
fprintf_plus(stderr, "Initializing GPGME\n");
199
304
gpgme_check_version(NULL);
200
305
rc = gpgme_engine_check_version(GPGME_PROTOCOL_OpenPGP);
201
306
if(rc != GPG_ERR_NO_ERROR){
202
fprintf(stderr, "bad gpgme_engine_check_version: %s: %s\n",
203
gpgme_strsource(rc), gpgme_strerror(rc));
307
fprintf_plus(stderr, "bad gpgme_engine_check_version: %s: %s\n",
308
gpgme_strsource(rc), gpgme_strerror(rc));
207
/* Set GPGME home directory for the OpenPGP engine only */
312
/* Set GPGME home directory for the OpenPGP engine only */
208
313
rc = gpgme_get_engine_info(&engine_info);
209
314
if(rc != GPG_ERR_NO_ERROR){
210
fprintf(stderr, "bad gpgme_get_engine_info: %s: %s\n",
211
gpgme_strsource(rc), gpgme_strerror(rc));
315
fprintf_plus(stderr, "bad gpgme_get_engine_info: %s: %s\n",
316
gpgme_strsource(rc), gpgme_strerror(rc));
214
319
while(engine_info != NULL){
507
629
__attribute__((unused)) const char *txt){}
509
631
/* Called when a Mandos server is found */
510
static int start_mandos_communication(const char *ip, uint16_t port,
632
static int start_mandos_communication(const char *ip, in_port_t port,
511
633
AvahiIfIndex if_index,
634
int af, mandos_context *mc){
635
int ret, tcp_sd = -1;
515
union { struct sockaddr in; struct sockaddr_in6 in6; } to;
638
struct sockaddr_in in;
639
struct sockaddr_in6 in6;
516
641
char *buffer = NULL;
517
char *decrypted_buffer;
642
char *decrypted_buffer = NULL;
518
643
size_t buffer_length = 0;
519
644
size_t buffer_capacity = 0;
520
ssize_t decrypted_buffer_size;
523
char interface[IF_NAMESIZE];
524
647
gnutls_session_t session;
526
ret = init_gnutls_session(mc, &session);
648
int pf; /* Protocol family */
665
fprintf_plus(stderr, "Bad address family: %d\n", af);
670
/* If the interface is specified and we have a list of interfaces */
671
if(if_index != AVAHI_IF_UNSPEC and mc->interfaces != NULL){
672
/* Check if the interface is one of the interfaces we are using */
675
char *interface = NULL;
676
while((interface=argz_next(mc->interfaces, mc->interfaces_size,
678
if(if_nametoindex(interface) == (unsigned int)if_index){
685
/* This interface does not match any in the list, so we don't
686
connect to the server */
688
char interface[IF_NAMESIZE];
689
if(if_indextoname((unsigned int)if_index, interface) == NULL){
690
perror_plus("if_indextoname");
692
fprintf_plus(stderr, "Skipping server on non-used interface"
694
if_indextoname((unsigned int)if_index,
702
ret = init_gnutls_session(&session, mc);
532
fprintf(stderr, "Setting up a tcp connection to %s, port %" PRIu16
708
fprintf_plus(stderr, "Setting up a TCP connection to %s, port %"
709
PRIuMAX "\n", ip, (uintmax_t)port);
536
tcp_sd = socket(PF_INET6, SOCK_STREAM, 0);
712
tcp_sd = socket(pf, SOCK_STREAM, 0);
715
perror_plus("socket");
543
if(if_indextoname((unsigned int)if_index, interface) == NULL){
544
perror("if_indextoname");
547
fprintf(stderr, "Binding to interface %s\n", interface);
550
725
memset(&to, 0, sizeof(to));
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);
727
to.in6.sin6_family = (sa_family_t)af;
728
ret = inet_pton(af, ip, &to.in6.sin6_addr);
730
to.in.sin_family = (sa_family_t)af;
731
ret = inet_pton(af, ip, &to.in.sin_addr);
735
perror_plus("inet_pton");
560
fprintf(stderr, "Bad address: %s\n", ip);
563
to.in6.sin6_port = htons(port); /* Spurious warnings from
565
-Wunreachable-code */
741
fprintf_plus(stderr, "Bad address: %s\n", ip);
746
to.in6.sin6_port = htons(port);
748
#pragma GCC diagnostic push
749
#pragma GCC diagnostic ignored "-Wstrict-aliasing"
751
if(IN6_IS_ADDR_LINKLOCAL /* Spurious warnings from */
752
(&to.in6.sin6_addr)){ /* -Wstrict-aliasing=2 or lower */
754
#pragma GCC diagnostic pop
756
if(if_index == AVAHI_IF_UNSPEC){
757
fprintf_plus(stderr, "An IPv6 link-local address is"
758
" incomplete without a network interface\n");
762
/* Set the network interface number as scope */
763
to.in6.sin6_scope_id = (uint32_t)if_index;
766
to.in.sin_port = htons(port);
567
to.in6.sin6_scope_id = (uint32_t)if_index;
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){
577
if(strcmp(addrstr, ip) != 0){
578
fprintf(stderr, "Canonical address form: %s\n", addrstr);
775
if(af == AF_INET6 and if_index != AVAHI_IF_UNSPEC){
776
char interface[IF_NAMESIZE];
777
if(if_indextoname((unsigned int)if_index, interface) == NULL){
778
perror_plus("if_indextoname");
780
fprintf_plus(stderr, "Connection to: %s%%%s, port %" PRIuMAX
781
"\n", ip, interface, (uintmax_t)port);
583
ret = connect(tcp_sd, &to.in, sizeof(to));
784
fprintf_plus(stderr, "Connection to: %s, port %" PRIuMAX "\n",
785
ip, (uintmax_t)port);
787
char addrstr[(INET_ADDRSTRLEN > INET6_ADDRSTRLEN) ?
788
INET_ADDRSTRLEN : INET6_ADDRSTRLEN] = "";
790
ret = getnameinfo((struct sockaddr *)&(to.in6), sizeof(to.in6),
791
addrstr, sizeof(addrstr), NULL, 0,
794
ret = getnameinfo((struct sockaddr *)&(to.in), sizeof(to.in),
795
addrstr, sizeof(addrstr), NULL, 0,
798
if(ret == EAI_SYSTEM){
799
perror_plus("getnameinfo");
800
} else if(ret != 0) {
801
fprintf_plus(stderr, "getnameinfo: %s", gai_strerror(ret));
802
} else if(strcmp(addrstr, ip) != 0){
803
fprintf_plus(stderr, "Canonical address form: %s\n", addrstr);
813
ret = connect(tcp_sd, &to.in6, sizeof(to));
815
ret = connect(tcp_sd, &to.in, sizeof(to)); /* IPv4 */
818
if ((errno != ECONNREFUSED and errno != ENETUNREACH) or debug){
820
perror_plus("connect");
589
831
const char *out = mandos_protocol_version;
815
1152
case AVAHI_BROWSER_ALL_FOR_NOW:
816
1153
case AVAHI_BROWSER_CACHE_EXHAUSTED:
818
fprintf(stderr, "No Mandos server found, still searching...\n");
1155
fprintf_plus(stderr, "No Mandos server found, still"
1162
/* Signal handler that stops main loop after SIGTERM */
1163
static void handle_sigterm(int sig){
1168
signal_received = sig;
1169
int old_errno = errno;
1170
/* set main loop to exit */
1171
if(simple_poll != NULL){
1172
avahi_simple_poll_quit(simple_poll);
1177
bool get_flags(const char *ifname, struct ifreq *ifr){
1181
int s = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP);
1184
perror_plus("socket");
1188
strcpy(ifr->ifr_name, ifname);
1189
ret = ioctl(s, SIOCGIFFLAGS, ifr);
1193
perror_plus("ioctl SIOCGIFFLAGS");
1201
bool good_flags(const char *ifname, const struct ifreq *ifr){
1203
/* Reject the loopback device */
1204
if(ifr->ifr_flags & IFF_LOOPBACK){
1206
fprintf_plus(stderr, "Rejecting loopback interface \"%s\"\n",
1211
/* Accept point-to-point devices only if connect_to is specified */
1212
if(connect_to != NULL and (ifr->ifr_flags & IFF_POINTOPOINT)){
1214
fprintf_plus(stderr, "Accepting point-to-point interface"
1215
" \"%s\"\n", ifname);
1219
/* Otherwise, reject non-broadcast-capable devices */
1220
if(not (ifr->ifr_flags & IFF_BROADCAST)){
1222
fprintf_plus(stderr, "Rejecting non-broadcast interface"
1223
" \"%s\"\n", ifname);
1227
/* Reject non-ARP interfaces (including dummy interfaces) */
1228
if(ifr->ifr_flags & IFF_NOARP){
1230
fprintf_plus(stderr, "Rejecting non-ARP interface \"%s\"\n",
1236
/* Accept this device */
1238
fprintf_plus(stderr, "Interface \"%s\" is good\n", ifname);
1244
* This function determines if a directory entry in /sys/class/net
1245
* corresponds to an acceptable network device.
1246
* (This function is passed to scandir(3) as a filter function.)
1248
int good_interface(const struct dirent *if_entry){
1249
if(if_entry->d_name[0] == '.'){
1254
if(not get_flags(if_entry->d_name, &ifr)){
1256
fprintf_plus(stderr, "Failed to get flags for interface "
1257
"\"%s\"\n", if_entry->d_name);
1262
if(not good_flags(if_entry->d_name, &ifr)){
1269
* This function determines if a network interface is up.
1271
bool interface_is_up(const char *interface){
1273
if(not get_flags(interface, &ifr)){
1275
fprintf_plus(stderr, "Failed to get flags for interface "
1276
"\"%s\"\n", interface);
1281
return (bool)(ifr.ifr_flags & IFF_UP);
1285
* This function determines if a network interface is running
1287
bool interface_is_running(const char *interface){
1289
if(not get_flags(interface, &ifr)){
1291
fprintf_plus(stderr, "Failed to get flags for interface "
1292
"\"%s\"\n", interface);
1297
return (bool)(ifr.ifr_flags & IFF_RUNNING);
1300
int notdotentries(const struct dirent *direntry){
1301
/* Skip "." and ".." */
1302
if(direntry->d_name[0] == '.'
1303
and (direntry->d_name[1] == '\0'
1304
or (direntry->d_name[1] == '.'
1305
and direntry->d_name[2] == '\0'))){
1311
/* Is this directory entry a runnable program? */
1312
int runnable_hook(const struct dirent *direntry){
1317
if((direntry->d_name)[0] == '\0'){
1322
sret = strspn(direntry->d_name, "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
1323
"abcdefghijklmnopqrstuvwxyz"
1326
if((direntry->d_name)[sret] != '\0'){
1327
/* Contains non-allowed characters */
1329
fprintf_plus(stderr, "Ignoring hook \"%s\" with bad name\n",
1335
char *fullname = NULL;
1336
ret = asprintf(&fullname, "%s/%s", hookdir, direntry->d_name);
1338
perror_plus("asprintf");
1342
ret = stat(fullname, &st);
1345
perror_plus("Could not stat hook");
1349
if(not (S_ISREG(st.st_mode))){
1350
/* Not a regular file */
1352
fprintf_plus(stderr, "Ignoring hook \"%s\" - not a file\n",
1357
if(not (st.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH))){
1358
/* Not executable */
1360
fprintf_plus(stderr, "Ignoring hook \"%s\" - not executable\n",
1366
fprintf_plus(stderr, "Hook \"%s\" is acceptable\n",
1372
int avahi_loop_with_timeout(AvahiSimplePoll *s, int retry_interval,
1373
mandos_context *mc){
1375
struct timespec now;
1376
struct timespec waited_time;
1377
intmax_t block_time;
1380
if(mc->current_server == NULL){
1382
fprintf_plus(stderr, "Wait until first server is found."
1385
ret = avahi_simple_poll_iterate(s, -1);
1388
fprintf_plus(stderr, "Check current_server if we should run"
1391
/* the current time */
1392
ret = clock_gettime(CLOCK_MONOTONIC, &now);
1394
perror_plus("clock_gettime");
1397
/* Calculating in ms how long time between now and server
1398
who we visted longest time ago. Now - last seen. */
1399
waited_time.tv_sec = (now.tv_sec
1400
- mc->current_server->last_seen.tv_sec);
1401
waited_time.tv_nsec = (now.tv_nsec
1402
- mc->current_server->last_seen.tv_nsec);
1403
/* total time is 10s/10,000ms.
1404
Converting to s from ms by dividing by 1,000,
1405
and ns to ms by dividing by 1,000,000. */
1406
block_time = ((retry_interval
1407
- ((intmax_t)waited_time.tv_sec * 1000))
1408
- ((intmax_t)waited_time.tv_nsec / 1000000));
1411
fprintf_plus(stderr, "Blocking for %" PRIdMAX " ms\n",
1415
if(block_time <= 0){
1416
ret = start_mandos_communication(mc->current_server->ip,
1417
mc->current_server->port,
1418
mc->current_server->if_index,
1419
mc->current_server->af, mc);
1421
avahi_simple_poll_quit(s);
1424
ret = clock_gettime(CLOCK_MONOTONIC,
1425
&mc->current_server->last_seen);
1427
perror_plus("clock_gettime");
1430
mc->current_server = mc->current_server->next;
1431
block_time = 0; /* Call avahi to find new Mandos
1432
servers, but don't block */
1435
ret = avahi_simple_poll_iterate(s, (int)block_time);
1438
if (ret > 0 or errno != EINTR){
1439
return (ret != 1) ? ret : 0;
1445
/* Set effective uid to 0, return errno */
1446
error_t raise_privileges(void){
1447
error_t old_errno = errno;
1448
error_t ret_errno = 0;
1449
if(seteuid(0) == -1){
1451
perror_plus("seteuid");
1457
/* Set effective and real user ID to 0. Return errno. */
1458
error_t raise_privileges_permanently(void){
1459
error_t old_errno = errno;
1460
error_t ret_errno = raise_privileges();
1465
if(setuid(0) == -1){
1467
perror_plus("seteuid");
1473
/* Set effective user ID to unprivileged saved user ID */
1474
error_t lower_privileges(void){
1475
error_t old_errno = errno;
1476
error_t ret_errno = 0;
1477
if(seteuid(uid) == -1){
1479
perror_plus("seteuid");
1485
/* Lower privileges permanently */
1486
error_t lower_privileges_permanently(void){
1487
error_t old_errno = errno;
1488
error_t ret_errno = 0;
1489
if(setuid(uid) == -1){
1491
perror_plus("setuid");
1497
bool run_network_hooks(const char *mode, const char *interface,
1499
struct dirent **direntries;
1500
int numhooks = scandir(hookdir, &direntries, runnable_hook,
1503
if(errno == ENOENT){
1505
fprintf_plus(stderr, "Network hook directory \"%s\" not"
1506
" found\n", hookdir);
1509
perror_plus("scandir");
1512
struct dirent *direntry;
1514
int devnull = open("/dev/null", O_RDONLY);
1515
for(int i = 0; i < numhooks; i++){
1516
direntry = direntries[i];
1517
char *fullname = NULL;
1518
ret = asprintf(&fullname, "%s/%s", hookdir, direntry->d_name);
1520
perror_plus("asprintf");
1524
fprintf_plus(stderr, "Running network hook \"%s\"\n",
1527
pid_t hook_pid = fork();
1530
/* Raise privileges */
1531
raise_privileges_permanently();
1536
perror_plus("setgid");
1538
/* Reset supplementary groups */
1540
ret = setgroups(0, NULL);
1542
perror_plus("setgroups");
1544
dup2(devnull, STDIN_FILENO);
1546
dup2(STDERR_FILENO, STDOUT_FILENO);
1547
ret = setenv("MANDOSNETHOOKDIR", hookdir, 1);
1549
perror_plus("setenv");
1552
ret = setenv("DEVICE", interface, 1);
1554
perror_plus("setenv");
1557
ret = setenv("VERBOSITY", debug ? "1" : "0", 1);
1559
perror_plus("setenv");
1562
ret = setenv("MODE", mode, 1);
1564
perror_plus("setenv");
1568
ret = asprintf(&delaystring, "%f", delay);
1570
perror_plus("asprintf");
1573
ret = setenv("DELAY", delaystring, 1);
1576
perror_plus("setenv");
1580
if(connect_to != NULL){
1581
ret = setenv("CONNECT", connect_to, 1);
1583
perror_plus("setenv");
1587
if(execl(fullname, direntry->d_name, mode, NULL) == -1){
1588
perror_plus("execl");
1589
_exit(EXIT_FAILURE);
1593
if(TEMP_FAILURE_RETRY(waitpid(hook_pid, &status, 0)) == -1){
1594
perror_plus("waitpid");
1598
if(WIFEXITED(status)){
1599
if(WEXITSTATUS(status) != 0){
1600
fprintf_plus(stderr, "Warning: network hook \"%s\" exited"
1601
" with status %d\n", direntry->d_name,
1602
WEXITSTATUS(status));
1606
} else if(WIFSIGNALED(status)){
1607
fprintf_plus(stderr, "Warning: network hook \"%s\" died by"
1608
" signal %d\n", direntry->d_name,
1613
fprintf_plus(stderr, "Warning: network hook \"%s\""
1614
" crashed\n", direntry->d_name);
1621
fprintf_plus(stderr, "Network hook \"%s\" ran successfully\n",
1630
error_t bring_up_interface(const char *const interface,
1633
error_t old_errno = errno;
1634
error_t ret_errno = 0;
1635
int ret, ret_setflags;
1636
struct ifreq network;
1637
unsigned int if_index = if_nametoindex(interface);
1639
fprintf_plus(stderr, "No such interface: \"%s\"\n", interface);
1649
if(not interface_is_up(interface)){
1650
if(not get_flags(interface, &network) and debug){
1652
fprintf_plus(stderr, "Failed to get flags for interface "
1653
"\"%s\"\n", interface);
1656
network.ifr_flags |= IFF_UP;
1658
sd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP);
1661
perror_plus("socket");
1673
fprintf_plus(stderr, "Bringing up interface \"%s\"\n",
1677
/* Raise priviliges */
1681
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1682
messages about the network interface to mess up the prompt */
1683
int ret_linux = klogctl(8, NULL, 5);
1684
bool restore_loglevel = true;
1685
if(ret_linux == -1){
1686
restore_loglevel = false;
1687
perror_plus("klogctl");
1689
#endif /* __linux__ */
1690
ret_setflags = ioctl(sd, SIOCSIFFLAGS, &network);
1693
if(restore_loglevel){
1694
ret_linux = klogctl(7, NULL, 0);
1695
if(ret_linux == -1){
1696
perror_plus("klogctl");
1699
#endif /* __linux__ */
1701
/* Lower privileges */
1704
/* Close the socket */
1705
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1707
perror_plus("close");
1710
if(ret_setflags == -1){
1712
perror_plus("ioctl SIOCSIFFLAGS +IFF_UP");
1717
fprintf_plus(stderr, "Interface \"%s\" is already up; good\n",
1721
/* Sleep checking until interface is running.
1722
Check every 0.25s, up to total time of delay */
1723
for(int i=0; i < delay * 4; i++){
1724
if(interface_is_running(interface)){
1727
struct timespec sleeptime = { .tv_nsec = 250000000 };
1728
ret = nanosleep(&sleeptime, NULL);
1729
if(ret == -1 and errno != EINTR){
1730
perror_plus("nanosleep");
1738
error_t take_down_interface(const char *const interface){
1739
error_t old_errno = errno;
1740
struct ifreq network;
1741
unsigned int if_index = if_nametoindex(interface);
1743
fprintf_plus(stderr, "No such interface: \"%s\"\n", interface);
1747
if(interface_is_up(interface)){
1748
error_t ret_errno = 0;
1749
if(not get_flags(interface, &network) and debug){
1751
fprintf_plus(stderr, "Failed to get flags for interface "
1752
"\"%s\"\n", interface);
1755
network.ifr_flags &= ~(short)IFF_UP; /* clear flag */
1757
int sd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP);
1760
perror_plus("socket");
1766
fprintf_plus(stderr, "Taking down interface \"%s\"\n",
1770
/* Raise priviliges */
1773
int ret_setflags = ioctl(sd, SIOCSIFFLAGS, &network);
1776
/* Lower privileges */
1779
/* Close the socket */
1780
int ret = (int)TEMP_FAILURE_RETRY(close(sd));
1782
perror_plus("close");
1785
if(ret_setflags == -1){
1787
perror_plus("ioctl SIOCSIFFLAGS -IFF_UP");
1792
fprintf_plus(stderr, "Interface \"%s\" is already down; odd\n",
824
1800
int main(int argc, char *argv[]){
1801
mandos_context mc = { .server = NULL, .dh_bits = 1024,
1802
.priority = "SECURE256:!CTYPE-X.509:"
1803
"+CTYPE-OPENPGP", .current_server = NULL,
1804
.interfaces = NULL, .interfaces_size = 0 };
825
1805
AvahiSServiceBrowser *sb = NULL;
828
1808
intmax_t tmpmax;
830
1810
int exitcode = EXIT_SUCCESS;
831
const char *interface = "eth0";
832
struct ifreq network;
836
char *connect_to = NULL;
1811
char *interfaces_to_take_down = NULL;
1812
size_t interfaces_to_take_down_size = 0;
837
1813
char tempdir[] = "/tmp/mandosXXXXXX";
838
1814
bool tempdir_created = false;
839
1815
AvahiIfIndex if_index = AVAHI_IF_UNSPEC;
840
1816
const char *seckey = PATHDIR "/" SECKEY;
841
1817
const char *pubkey = PATHDIR "/" PUBKEY;
1818
char *interfaces_hooks = NULL;
843
mandos_context mc = { .simple_poll = NULL, .server = NULL,
844
.dh_bits = 1024, .priority = "SECURE256"
845
":!CTYPE-X.509:+CTYPE-OPENPGP" };
846
1820
bool gnutls_initialized = false;
847
1821
bool gpgme_initialized = false;
1823
double retry_interval = 10; /* 10s between trying a server and
1824
retrying the same server again */
1826
struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };
1827
struct sigaction sigterm_action = { .sa_handler = handle_sigterm };
1832
/* Lower any group privileges we might have, just to be safe */
1836
perror_plus("setgid");
1839
/* Lower user privileges (temporarily) */
1843
perror_plus("seteuid");
851
1851
struct argp_option options[] = {
915
1937
mc.priority = arg;
917
1939
case 131: /* --delay */
918
ret = sscanf(arg, "%lf%n", &delay, &numchars);
919
if(ret < 1 or arg[numchars] != '\0'){
920
fprintf(stderr, "Bad delay\n");
1941
delay = strtof(arg, &tmp);
1942
if(errno != 0 or tmp == arg or *tmp != '\0'){
1943
argp_error(state, "Bad delay");
1945
case 132: /* --retry */
1947
retry_interval = strtod(arg, &tmp);
1948
if(errno != 0 or tmp == arg or *tmp != '\0'
1949
or (retry_interval * 1000) > INT_MAX
1950
or retry_interval < 0){
1951
argp_error(state, "Bad retry interval");
1954
case 133: /* --network-hook-dir */
1958
* These reproduce what we would get without ARGP_NO_HELP
1960
case '?': /* --help */
1961
argp_state_help(state, state->out_stream,
1962
(ARGP_HELP_STD_HELP | ARGP_HELP_EXIT_ERR)
1963
& ~(unsigned int)ARGP_HELP_EXIT_OK);
1964
case -3: /* --usage */
1965
argp_state_help(state, state->out_stream,
1966
ARGP_HELP_USAGE | ARGP_HELP_EXIT_ERR);
1967
case 'V': /* --version */
1968
fprintf_plus(state->out_stream, "%s\n", argp_program_version);
1969
exit(argp_err_exit_status);
929
1972
return ARGP_ERR_UNKNOWN;
934
1977
struct argp argp = { .options = options, .parser = parse_opt,
936
1979
.doc = "Mandos client -- Get and decrypt"
937
1980
" passwords from a Mandos server" };
938
ret = argp_parse(&argp, argc, argv, 0, 0, NULL);
939
if(ret == ARGP_ERR_UNKNOWN){
940
fprintf(stderr, "Unknown error while parsing arguments\n");
941
exitcode = EXIT_FAILURE;
946
/* If the interface is down, bring it up */
949
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
950
messages to mess up the prompt */
951
ret = klogctl(8, NULL, 5);
957
sd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP);
960
exitcode = EXIT_FAILURE;
962
ret = klogctl(7, NULL, 0);
969
strcpy(network.ifr_name, interface);
970
ret = ioctl(sd, SIOCGIFFLAGS, &network);
972
perror("ioctl SIOCGIFFLAGS");
974
ret = klogctl(7, NULL, 0);
979
exitcode = EXIT_FAILURE;
982
if((network.ifr_flags & IFF_UP) == 0){
983
network.ifr_flags |= IFF_UP;
984
ret = ioctl(sd, SIOCSIFFLAGS, &network);
986
perror("ioctl SIOCSIFFLAGS");
987
exitcode = EXIT_FAILURE;
989
ret = klogctl(7, NULL, 0);
1981
ret = argp_parse(&argp, argc, argv,
1982
ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);
1989
perror_plus("argp_parse");
1990
exitcode = EX_OSERR;
1993
exitcode = EX_USAGE;
1999
/* Work around Debian bug #633582:
2000
<http://bugs.debian.org/633582> */
2002
/* Re-raise priviliges */
2003
if(raise_privileges() == 0){
2006
if(strcmp(seckey, PATHDIR "/" SECKEY) == 0){
2007
int seckey_fd = open(seckey, O_RDONLY);
2008
if(seckey_fd == -1){
2009
perror_plus("open");
2011
ret = (int)TEMP_FAILURE_RETRY(fstat(seckey_fd, &st));
2013
perror_plus("fstat");
2015
if(S_ISREG(st.st_mode)
2016
and st.st_uid == 0 and st.st_gid == 0){
2017
ret = fchown(seckey_fd, uid, gid);
2019
perror_plus("fchown");
2023
TEMP_FAILURE_RETRY(close(seckey_fd));
2027
if(strcmp(pubkey, PATHDIR "/" PUBKEY) == 0){
2028
int pubkey_fd = open(pubkey, O_RDONLY);
2029
if(pubkey_fd == -1){
2030
perror_plus("open");
2032
ret = (int)TEMP_FAILURE_RETRY(fstat(pubkey_fd, &st));
2034
perror_plus("fstat");
2036
if(S_ISREG(st.st_mode)
2037
and st.st_uid == 0 and st.st_gid == 0){
2038
ret = fchown(pubkey_fd, uid, gid);
2040
perror_plus("fchown");
2044
TEMP_FAILURE_RETRY(close(pubkey_fd));
2048
/* Lower privileges */
2053
/* Remove invalid interface names (except "none") */
2055
char *interface = NULL;
2056
while((interface = argz_next(mc.interfaces, mc.interfaces_size,
2058
if(strcmp(interface, "none") != 0
2059
and if_nametoindex(interface) == 0){
2060
if(interface[0] != '\0'){
2061
fprintf_plus(stderr, "Not using nonexisting interface"
2062
" \"%s\"\n", interface);
2064
argz_delete(&mc.interfaces, &mc.interfaces_size, interface);
2070
/* Run network hooks */
2072
if(mc.interfaces != NULL){
2073
interfaces_hooks = malloc(mc.interfaces_size);
2074
if(interfaces_hooks == NULL){
2075
perror_plus("malloc");
997
/* sleep checking until interface is running */
998
for(int i=0; i < delay * 4; i++){
999
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1001
perror("ioctl SIOCGIFFLAGS");
1002
} else if(network.ifr_flags & IFF_RUNNING){
2078
memcpy(interfaces_hooks, mc.interfaces, mc.interfaces_size);
2079
argz_stringify(interfaces_hooks, mc.interfaces_size, (int)',');
2081
if(not run_network_hooks("start", interfaces_hooks != NULL ?
2082
interfaces_hooks : "", delay)){
2088
avahi_set_log_function(empty_log);
2091
/* Initialize Avahi early so avahi_simple_poll_quit() can be called
2092
from the signal handler */
2093
/* Initialize the pseudo-RNG for Avahi */
2094
srand((unsigned int) time(NULL));
2095
simple_poll = avahi_simple_poll_new();
2096
if(simple_poll == NULL){
2097
fprintf_plus(stderr,
2098
"Avahi: Failed to create simple poll object.\n");
2099
exitcode = EX_UNAVAILABLE;
2103
sigemptyset(&sigterm_action.sa_mask);
2104
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
2106
perror_plus("sigaddset");
2107
exitcode = EX_OSERR;
2110
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
2112
perror_plus("sigaddset");
2113
exitcode = EX_OSERR;
2116
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
2118
perror_plus("sigaddset");
2119
exitcode = EX_OSERR;
2122
/* Need to check if the handler is SIG_IGN before handling:
2123
| [[info:libc:Initial Signal Actions]] |
2124
| [[info:libc:Basic Signal Handling]] |
2126
ret = sigaction(SIGINT, NULL, &old_sigterm_action);
2128
perror_plus("sigaction");
2131
if(old_sigterm_action.sa_handler != SIG_IGN){
2132
ret = sigaction(SIGINT, &sigterm_action, NULL);
2134
perror_plus("sigaction");
2135
exitcode = EX_OSERR;
2139
ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
2141
perror_plus("sigaction");
2144
if(old_sigterm_action.sa_handler != SIG_IGN){
2145
ret = sigaction(SIGHUP, &sigterm_action, NULL);
2147
perror_plus("sigaction");
2148
exitcode = EX_OSERR;
2152
ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
2154
perror_plus("sigaction");
2157
if(old_sigterm_action.sa_handler != SIG_IGN){
2158
ret = sigaction(SIGTERM, &sigterm_action, NULL);
2160
perror_plus("sigaction");
2161
exitcode = EX_OSERR;
2166
/* If no interfaces were specified, make a list */
2167
if(mc.interfaces == NULL){
2168
struct dirent **direntries;
2169
/* Look for any good interfaces */
2170
ret = scandir(sys_class_net, &direntries, good_interface,
2173
/* Add all found interfaces to interfaces list */
2174
for(int i = 0; i < ret; ++i){
2175
ret_errno = argz_add(&mc.interfaces, &mc.interfaces_size,
2176
direntries[i]->d_name);
2179
perror_plus("argz_add");
2183
fprintf_plus(stderr, "Will use interface \"%s\"\n",
2184
direntries[i]->d_name);
2190
fprintf_plus(stderr, "Could not find a network interface\n");
2191
exitcode = EXIT_FAILURE;
2196
/* Bring up interfaces which are down, and remove any "none"s */
2198
char *interface = NULL;
2199
while((interface = argz_next(mc.interfaces, mc.interfaces_size,
2201
/* If interface name is "none", stop bringing up interfaces.
2202
Also remove all instances of "none" from the list */
2203
if(strcmp(interface, "none") == 0){
2204
argz_delete(&mc.interfaces, &mc.interfaces_size,
2207
while((interface = argz_next(mc.interfaces,
2208
mc.interfaces_size, interface))){
2209
if(strcmp(interface, "none") == 0){
2210
argz_delete(&mc.interfaces, &mc.interfaces_size,
1005
struct timespec sleeptime = { .tv_nsec = 250000000 };
1006
ret = nanosleep(&sleeptime, NULL);
1007
if(ret == -1 and errno != EINTR){
1008
perror("nanosleep");
2217
bool interface_was_up = interface_is_up(interface);
2218
ret = bring_up_interface(interface, delay);
2219
if(not interface_was_up){
2222
perror_plus("Failed to bring up interface");
2224
ret_errno = argz_add(&interfaces_to_take_down,
2225
&interfaces_to_take_down_size,
2229
perror_plus("argz_add");
1011
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1016
/* Restores kernel loglevel to default */
1017
ret = klogctl(7, NULL, 0);
1037
ret = init_gnutls_global(&mc, pubkey, seckey);
1039
fprintf(stderr, "init_gnutls_global failed\n");
1040
exitcode = EXIT_FAILURE;
2234
if(debug and (interfaces_to_take_down == NULL)){
2235
fprintf_plus(stderr, "No interfaces were brought up\n");
2239
/* If we only got one interface, explicitly use only that one */
2240
if(argz_count(mc.interfaces, mc.interfaces_size) == 1){
2242
fprintf_plus(stderr, "Using only interface \"%s\"\n",
2245
if_index = (AvahiIfIndex)if_nametoindex(mc.interfaces);
2252
ret = init_gnutls_global(pubkey, seckey, &mc);
2254
fprintf_plus(stderr, "init_gnutls_global failed\n");
2255
exitcode = EX_UNAVAILABLE;
1043
2258
gnutls_initialized = true;
1046
2265
if(mkdtemp(tempdir) == NULL){
2266
perror_plus("mkdtemp");
1050
2269
tempdir_created = true;
1052
if(not init_gpgme(&mc, pubkey, seckey, tempdir)){
1053
fprintf(stderr, "init_gpgme failed\n");
1054
exitcode = EXIT_FAILURE;
2275
if(not init_gpgme(pubkey, seckey, tempdir, &mc)){
2276
fprintf_plus(stderr, "init_gpgme failed\n");
2277
exitcode = EX_UNAVAILABLE;
1057
2280
gpgme_initialized = true;
1060
if_index = (AvahiIfIndex) if_nametoindex(interface);
1062
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1063
exitcode = EXIT_FAILURE;