40
40
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), asprintf() */
42
42
#include <stdio.h> /* fprintf(), stderr, fwrite(),
43
stdout, ferror(), remove() */
44
44
#include <stdint.h> /* uint16_t, uint32_t, intptr_t */
45
45
#include <stddef.h> /* NULL, size_t, ssize_t */
46
46
#include <stdlib.h> /* free(), EXIT_SUCCESS, srand(),
47
47
strtof(), abort() */
48
48
#include <stdbool.h> /* bool, false, true */
49
#include <string.h> /* memset(), strcmp(), strlen(),
50
strerror(), asprintf(), strcpy() */
49
#include <string.h> /* strcmp(), strlen(), strerror(),
50
asprintf(), strncpy(), strsignal()
51
52
#include <sys/ioctl.h> /* ioctl */
52
53
#include <sys/types.h> /* socket(), inet_pton(), sockaddr,
53
54
sockaddr_in6, PF_INET6,
57
58
#include <sys/socket.h> /* socket(), struct sockaddr_in6,
58
59
inet_pton(), connect(),
60
#include <fcntl.h> /* open() */
61
#include <fcntl.h> /* open(), unlinkat(), AT_REMOVEDIR */
61
62
#include <dirent.h> /* opendir(), struct dirent, readdir()
63
64
#include <inttypes.h> /* PRIu16, PRIdMAX, intmax_t,
65
#include <errno.h> /* perror(), errno,
66
#include <errno.h> /* perror(), errno, EINTR, EINVAL,
67
EAI_SYSTEM, ENETUNREACH,
68
EHOSTUNREACH, ECONNREFUSED, EPROTO,
69
EIO, ENOENT, ENXIO, ENOMEM, EISDIR,
66
71
program_invocation_short_name */
67
72
#include <time.h> /* nanosleep(), time(), sleep() */
68
73
#include <net/if.h> /* ioctl, ifreq, SIOCGIFFLAGS, IFF_UP,
497
518
fprintf_plus(stderr, "GnuTLS: %s", string);
500
__attribute__((nonnull, warn_unused_result))
521
__attribute__((nonnull(1, 2, 4), warn_unused_result))
501
522
static int init_gnutls_global(const char *pubkeyfilename,
502
523
const char *seckeyfilename,
524
const char *dhparamsfilename,
503
525
mandos_context *mc){
507
530
fprintf_plus(stderr, "Initializing GnuTLS\n");
510
ret = gnutls_global_init();
511
if(ret != GNUTLS_E_SUCCESS){
512
fprintf_plus(stderr, "GnuTLS global_init: %s\n",
513
safer_gnutls_strerror(ret));
518
534
/* "Use a log level over 10 to enable all debugging options."
519
535
* - GnuTLS manual
558
573
safer_gnutls_strerror(ret));
561
ret = gnutls_dh_params_generate2(mc->dh_params, mc->dh_bits);
562
if(ret != GNUTLS_E_SUCCESS){
563
fprintf_plus(stderr, "Error in GnuTLS prime generation: %s\n",
564
safer_gnutls_strerror(ret));
576
/* If a Diffie-Hellman parameters file was given, try to use it */
577
if(dhparamsfilename != NULL){
578
gnutls_datum_t params = { .data = NULL, .size = 0 };
580
int dhpfile = open(dhparamsfilename, O_RDONLY);
583
dhparamsfilename = NULL;
586
size_t params_capacity = 0;
588
params_capacity = incbuffer((char **)¶ms.data,
590
(size_t)params_capacity);
591
if(params_capacity == 0){
592
perror_plus("incbuffer");
595
dhparamsfilename = NULL;
598
ssize_t bytes_read = read(dhpfile,
599
params.data + params.size,
605
/* check bytes_read for failure */
610
dhparamsfilename = NULL;
613
params.size += (unsigned int)bytes_read;
615
if(params.data == NULL){
616
dhparamsfilename = NULL;
618
if(dhparamsfilename == NULL){
621
ret = gnutls_dh_params_import_pkcs3(mc->dh_params, ¶ms,
622
GNUTLS_X509_FMT_PEM);
623
if(ret != GNUTLS_E_SUCCESS){
624
fprintf_plus(stderr, "Failed to parse DH parameters in file"
625
" \"%s\": %s\n", dhparamsfilename,
626
safer_gnutls_strerror(ret));
627
dhparamsfilename = NULL;
632
if(dhparamsfilename == NULL){
633
if(mc->dh_bits == 0){
634
/* Find out the optimal number of DH bits */
635
/* Try to read the private key file */
636
gnutls_datum_t buffer = { .data = NULL, .size = 0 };
638
int secfile = open(seckeyfilename, O_RDONLY);
643
size_t buffer_capacity = 0;
645
buffer_capacity = incbuffer((char **)&buffer.data,
647
(size_t)buffer_capacity);
648
if(buffer_capacity == 0){
649
perror_plus("incbuffer");
654
ssize_t bytes_read = read(secfile,
655
buffer.data + buffer.size,
661
/* check bytes_read for failure */
668
buffer.size += (unsigned int)bytes_read;
672
/* If successful, use buffer to parse private key */
673
gnutls_sec_param_t sec_param = GNUTLS_SEC_PARAM_ULTRA;
674
if(buffer.data != NULL){
676
gnutls_openpgp_privkey_t privkey = NULL;
677
ret = gnutls_openpgp_privkey_init(&privkey);
678
if(ret != GNUTLS_E_SUCCESS){
679
fprintf_plus(stderr, "Error initializing OpenPGP key"
681
safer_gnutls_strerror(ret));
685
ret = gnutls_openpgp_privkey_import
686
(privkey, &buffer, GNUTLS_OPENPGP_FMT_BASE64, "", 0);
687
if(ret != GNUTLS_E_SUCCESS){
688
fprintf_plus(stderr, "Error importing OpenPGP key : %s",
689
safer_gnutls_strerror(ret));
695
/* Use private key to suggest an appropriate
697
sec_param = gnutls_openpgp_privkey_sec_param(privkey);
698
gnutls_openpgp_privkey_deinit(privkey);
700
fprintf_plus(stderr, "This OpenPGP key implies using"
701
" a GnuTLS security parameter \"%s\".\n",
702
safe_string(gnutls_sec_param_get_name
708
if(sec_param == GNUTLS_SEC_PARAM_UNKNOWN){
709
/* Err on the side of caution */
710
sec_param = GNUTLS_SEC_PARAM_ULTRA;
712
fprintf_plus(stderr, "Falling back to security parameter"
714
safe_string(gnutls_sec_param_get_name
719
uret = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, sec_param);
723
fprintf_plus(stderr, "A \"%s\" GnuTLS security parameter"
724
" implies %u DH bits; using that.\n",
725
safe_string(gnutls_sec_param_get_name
730
fprintf_plus(stderr, "Failed to get implied number of DH"
731
" bits for security parameter \"%s\"): %s\n",
732
safe_string(gnutls_sec_param_get_name
734
safer_gnutls_strerror(ret));
738
fprintf_plus(stderr, "DH bits explicitly set to %u\n",
741
ret = gnutls_dh_params_generate2(mc->dh_params, mc->dh_bits);
742
if(ret != GNUTLS_E_SUCCESS){
743
fprintf_plus(stderr, "Error in GnuTLS prime generation (%u"
744
" bits): %s\n", mc->dh_bits,
745
safer_gnutls_strerror(ret));
568
749
gnutls_certificate_set_dh_params(mc->cred, mc->dh_params);
639
817
static void empty_log(__attribute__((unused)) AvahiLogLevel level,
640
818
__attribute__((unused)) const char *txt){}
820
/* Set effective uid to 0, return errno */
821
__attribute__((warn_unused_result))
822
int raise_privileges(void){
823
int old_errno = errno;
825
if(seteuid(0) == -1){
832
/* Set effective and real user ID to 0. Return errno. */
833
__attribute__((warn_unused_result))
834
int raise_privileges_permanently(void){
835
int old_errno = errno;
836
int ret = raise_privileges();
848
/* Set effective user ID to unprivileged saved user ID */
849
__attribute__((warn_unused_result))
850
int lower_privileges(void){
851
int old_errno = errno;
853
if(seteuid(uid) == -1){
860
/* Lower privileges permanently */
861
__attribute__((warn_unused_result))
862
int lower_privileges_permanently(void){
863
int old_errno = errno;
865
if(setuid(uid) == -1){
872
/* Helper function to add_local_route() and delete_local_route() */
873
__attribute__((nonnull, warn_unused_result))
874
static bool add_delete_local_route(const bool add,
876
AvahiIfIndex if_index){
878
char helper[] = "mandos-client-iprouteadddel";
879
char add_arg[] = "add";
880
char delete_arg[] = "delete";
881
char debug_flag[] = "--debug";
882
char *pluginhelperdir = getenv("MANDOSPLUGINHELPERDIR");
883
if(pluginhelperdir == NULL){
885
fprintf_plus(stderr, "MANDOSPLUGINHELPERDIR environment"
886
" variable not set; cannot run helper\n");
891
char interface[IF_NAMESIZE];
892
if(if_indextoname((unsigned int)if_index, interface) == NULL){
893
perror_plus("if_indextoname");
897
int devnull = (int)TEMP_FAILURE_RETRY(open("/dev/null", O_RDONLY));
899
perror_plus("open(\"/dev/null\", O_RDONLY)");
905
/* Raise privileges */
906
errno = raise_privileges_permanently();
908
perror_plus("Failed to raise privileges");
909
/* _exit(EX_NOPERM); */
915
perror_plus("setgid");
918
/* Reset supplementary groups */
920
ret = setgroups(0, NULL);
922
perror_plus("setgroups");
926
ret = dup2(devnull, STDIN_FILENO);
928
perror_plus("dup2(devnull, STDIN_FILENO)");
931
ret = close(devnull);
933
perror_plus("close");
936
ret = dup2(STDERR_FILENO, STDOUT_FILENO);
938
perror_plus("dup2(STDERR_FILENO, STDOUT_FILENO)");
941
int helperdir_fd = (int)TEMP_FAILURE_RETRY(open(pluginhelperdir,
946
if(helperdir_fd == -1){
948
_exit(EX_UNAVAILABLE);
950
int helper_fd = (int)TEMP_FAILURE_RETRY(openat(helperdir_fd,
953
perror_plus("openat");
955
_exit(EX_UNAVAILABLE);
959
#pragma GCC diagnostic push
960
#pragma GCC diagnostic ignored "-Wcast-qual"
962
if(fexecve(helper_fd, (char *const [])
963
{ helper, add ? add_arg : delete_arg, (char *)address,
964
interface, debug ? debug_flag : NULL, NULL },
967
#pragma GCC diagnostic pop
969
perror_plus("fexecve");
981
pret = waitpid(pid, &status, 0);
982
if(pret == -1 and errno == EINTR and quit_now){
983
int errno_raising = 0;
984
if((errno = raise_privileges()) != 0){
985
errno_raising = errno;
986
perror_plus("Failed to raise privileges in order to"
987
" kill helper program");
989
if(kill(pid, SIGTERM) == -1){
992
if((errno_raising == 0) and (errno = lower_privileges()) != 0){
993
perror_plus("Failed to lower privileges after killing"
998
} while(pret == -1 and errno == EINTR);
1000
perror_plus("waitpid");
1003
if(WIFEXITED(status)){
1004
if(WEXITSTATUS(status) != 0){
1005
fprintf_plus(stderr, "Error: iprouteadddel exited"
1006
" with status %d\n", WEXITSTATUS(status));
1011
if(WIFSIGNALED(status)){
1012
fprintf_plus(stderr, "Error: iprouteadddel died by"
1013
" signal %d\n", WTERMSIG(status));
1016
fprintf_plus(stderr, "Error: iprouteadddel crashed\n");
1020
__attribute__((nonnull, warn_unused_result))
1021
static bool add_local_route(const char *address,
1022
AvahiIfIndex if_index){
1024
fprintf_plus(stderr, "Adding route to %s\n", address);
1026
return add_delete_local_route(true, address, if_index);
1029
__attribute__((nonnull, warn_unused_result))
1030
static bool delete_local_route(const char *address,
1031
AvahiIfIndex if_index){
1033
fprintf_plus(stderr, "Removing route to %s\n", address);
1035
return add_delete_local_route(false, address, if_index);
642
1038
/* Called when a Mandos server is found */
643
1039
__attribute__((nonnull, warn_unused_result))
644
1040
static int start_mandos_communication(const char *ip, in_port_t port,
731
1128
goto mandos_end;
734
memset(&to, 0, sizeof(to));
735
1131
if(af == AF_INET6){
736
((struct sockaddr_in6 *)&to)->sin6_family = (sa_family_t)af;
737
ret = inet_pton(af, ip, &((struct sockaddr_in6 *)&to)->sin6_addr);
1132
struct sockaddr_in6 *to6 = (struct sockaddr_in6 *)&to;
1133
*to6 = (struct sockaddr_in6){ .sin6_family = (sa_family_t)af };
1134
ret = inet_pton(af, ip, &to6->sin6_addr);
738
1135
} else { /* IPv4 */
739
((struct sockaddr_in *)&to)->sin_family = (sa_family_t)af;
740
ret = inet_pton(af, ip, &((struct sockaddr_in *)&to)->sin_addr);
1136
struct sockaddr_in *to4 = (struct sockaddr_in *)&to;
1137
*to4 = (struct sockaddr_in){ .sin_family = (sa_family_t)af };
1138
ret = inet_pton(af, ip, &to4->sin_addr);
813
1211
goto mandos_end;
817
ret = connect(tcp_sd, (struct sockaddr *)&to,
818
sizeof(struct sockaddr_in6));
820
ret = connect(tcp_sd, (struct sockaddr *)&to, /* IPv4 */
821
sizeof(struct sockaddr_in));
824
if((errno != ECONNREFUSED and errno != ENETUNREACH) or debug){
826
perror_plus("connect");
1216
ret = connect(tcp_sd, (struct sockaddr *)&to,
1217
sizeof(struct sockaddr_in6));
1219
ret = connect(tcp_sd, (struct sockaddr *)&to, /* IPv4 */
1220
sizeof(struct sockaddr_in));
1223
if(((errno == ENETUNREACH) or (errno == EHOSTUNREACH))
1224
and if_index != AVAHI_IF_UNSPEC
1225
and connect_to == NULL
1226
and not route_added and
1227
((af == AF_INET6 and not
1228
IN6_IS_ADDR_LINKLOCAL(&(((struct sockaddr_in6 *)
1230
or (af == AF_INET and
1231
/* Not a a IPv4LL address */
1232
(ntohl(((struct sockaddr_in *)&to)->sin_addr.s_addr)
1233
& 0xFFFF0000L) != 0xA9FE0000L))){
1234
/* Work around Avahi bug - Avahi does not announce link-local
1235
addresses if it has a global address, so local hosts with
1236
*only* a link-local address (e.g. Mandos clients) cannot
1237
connect to a Mandos server announced by Avahi on a server
1238
host with a global address. Work around this by retrying
1239
with an explicit route added with the server's address.
1241
Avahi bug reference:
1242
https://lists.freedesktop.org/archives/avahi/2010-February/001833.html
1243
https://bugs.debian.org/587961
1246
fprintf_plus(stderr, "Mandos server unreachable, trying"
1250
route_added = add_local_route(ip, if_index);
1256
if(errno != ECONNREFUSED or debug){
1258
perror_plus("connect");
837
1271
const char *out = mandos_protocol_version;
1453
/* Set effective uid to 0, return errno */
1454
__attribute__((warn_unused_result))
1455
error_t raise_privileges(void){
1456
error_t old_errno = errno;
1457
error_t ret_errno = 0;
1458
if(seteuid(0) == -1){
1460
perror_plus("seteuid");
1466
/* Set effective and real user ID to 0. Return errno. */
1467
__attribute__((warn_unused_result))
1468
error_t raise_privileges_permanently(void){
1469
error_t old_errno = errno;
1470
error_t ret_errno = raise_privileges();
1475
if(setuid(0) == -1){
1477
perror_plus("seteuid");
1483
/* Set effective user ID to unprivileged saved user ID */
1484
__attribute__((warn_unused_result))
1485
error_t lower_privileges(void){
1486
error_t old_errno = errno;
1487
error_t ret_errno = 0;
1488
if(seteuid(uid) == -1){
1490
perror_plus("seteuid");
1496
/* Lower privileges permanently */
1497
__attribute__((warn_unused_result))
1498
error_t lower_privileges_permanently(void){
1499
error_t old_errno = errno;
1500
error_t ret_errno = 0;
1501
if(setuid(uid) == -1){
1503
perror_plus("setuid");
1511
* Based on the example in the GNU LibC manual chapter 13.13 "File
1512
* Descriptor Flags".
1513
| [[info:libc:Descriptor%20Flags][File Descriptor Flags]] |
1515
__attribute__((warn_unused_result))
1516
static int set_cloexec_flag(int fd){
1517
int ret = (int)TEMP_FAILURE_RETRY(fcntl(fd, F_GETFD, 0));
1518
/* If reading the flags failed, return error indication now. */
1522
/* Store modified flag word in the descriptor. */
1523
return (int)TEMP_FAILURE_RETRY(fcntl(fd, F_SETFD,
1526
#endif /* not O_CLOEXEC */
1528
1906
__attribute__((nonnull))
1529
1907
void run_network_hooks(const char *mode, const char *interface,
1530
1908
const float delay){
1531
struct dirent **direntries;
1909
struct dirent **direntries = NULL;
1532
1910
if(hookdir_fd == -1){
1533
hookdir_fd = open(hookdir, O_RDONLY |
1536
#else /* not O_CLOEXEC */
1538
#endif /* not O_CLOEXEC */
1911
hookdir_fd = open(hookdir, O_RDONLY | O_DIRECTORY | O_PATH
1540
1913
if(hookdir_fd == -1){
1541
1914
if(errno == ENOENT){
1552
if(set_cloexec_flag(hookdir_fd) < 0){
1553
perror_plus("set_cloexec_flag");
1554
if((int)TEMP_FAILURE_RETRY(close(hookdir_fd)) == -1){
1555
perror_plus("close");
1561
#endif /* not O_CLOEXEC */
1564
#if __GLIBC_PREREQ(2, 15)
1565
1925
int numhooks = scandirat(hookdir_fd, ".", &direntries,
1566
1926
runnable_hook, alphasort);
1567
#else /* not __GLIBC_PREREQ(2, 15) */
1568
int numhooks = scandir(hookdir, &direntries, runnable_hook,
1570
#endif /* not __GLIBC_PREREQ(2, 15) */
1571
#else /* not __GLIBC__ */
1572
int numhooks = scandir(hookdir, &direntries, runnable_hook,
1574
#endif /* not __GLIBC__ */
1575
1927
if(numhooks == -1){
1576
1928
perror_plus("scandir");
1579
1931
struct dirent *direntry;
1581
int devnull = open("/dev/null", O_RDONLY);
1933
int devnull = (int)TEMP_FAILURE_RETRY(open("/dev/null", O_RDONLY));
1935
perror_plus("open(\"/dev/null\", O_RDONLY)");
1582
1938
for(int i = 0; i < numhooks; i++){
1583
1939
direntry = direntries[i];
1662
2004
_exit(EX_OSERR);
1665
if(fexecve(hookdir_fd, (char *const [])
1666
{ direntry->d_name, NULL }, environ) == -1){
2007
int hook_fd = (int)TEMP_FAILURE_RETRY(openat(hookdir_fd,
2011
perror_plus("openat");
2012
_exit(EXIT_FAILURE);
2014
if(close(hookdir_fd) == -1){
2015
perror_plus("close");
2016
_exit(EXIT_FAILURE);
2018
ret = dup2(devnull, STDIN_FILENO);
2020
perror_plus("dup2(devnull, STDIN_FILENO)");
2023
ret = close(devnull);
2025
perror_plus("close");
2028
ret = dup2(STDERR_FILENO, STDOUT_FILENO);
2030
perror_plus("dup2(STDERR_FILENO, STDOUT_FILENO)");
2033
if(fexecve(hook_fd, (char *const []){ direntry->d_name, NULL },
1667
2035
perror_plus("fexecve");
1668
2036
_exit(EXIT_FAILURE);
2040
perror_plus("fork");
1672
2045
if(TEMP_FAILURE_RETRY(waitpid(hook_pid, &status, 0)) == -1){
1673
2046
perror_plus("waitpid");
1676
2050
if(WIFEXITED(status)){
2614
3049
free(interfaces_to_take_down);
2615
3050
free(interfaces_hooks);
3052
void clean_dir_at(int base, const char * const dirname,
3054
struct dirent **direntries = NULL;
3056
int dir_fd = (int)TEMP_FAILURE_RETRY(openat(base, dirname,
3062
perror_plus("open");
3064
int numentries = scandirat(dir_fd, ".", &direntries,
3065
notdotentries, alphasort);
3066
if(numentries >= 0){
3067
for(int i = 0; i < numentries; i++){
3069
fprintf_plus(stderr, "Unlinking \"%s/%s\"\n",
3070
dirname, direntries[i]->d_name);
3072
dret = unlinkat(dir_fd, direntries[i]->d_name, 0);
3074
if(errno == EISDIR){
3075
dret = unlinkat(dir_fd, direntries[i]->d_name,
3078
if((dret == -1) and (errno == ENOTEMPTY)
3079
and (strcmp(direntries[i]->d_name, "private-keys-v1.d")
3080
== 0) and (level == 0)){
3081
/* Recurse only in this special case */
3082
clean_dir_at(dir_fd, direntries[i]->d_name, level+1);
3086
fprintf_plus(stderr, "unlink(\"%s/%s\"): %s\n", dirname,
3087
direntries[i]->d_name, strerror(errno));
3090
free(direntries[i]);
3093
/* need to clean even if 0 because man page doesn't specify */
3095
if(numentries == -1){
3096
perror_plus("scandirat");
3098
dret = unlinkat(base, dirname, AT_REMOVEDIR);
3099
if(dret == -1 and errno != ENOENT){
3100
perror_plus("rmdir");
3103
perror_plus("scandirat");
2617
3108
/* Removes the GPGME temp directory and all files inside */
2618
3109
if(tempdir != NULL){
2619
struct dirent **direntries = NULL;
2620
struct dirent *direntry = NULL;
2621
int numentries = scandir(tempdir, &direntries, notdotentries,
2624
for(int i = 0; i < numentries; i++){
2625
direntry = direntries[i];
2626
char *fullname = NULL;
2627
ret = asprintf(&fullname, "%s/%s", tempdir,
2630
perror_plus("asprintf");
2633
ret = remove(fullname);
2635
fprintf_plus(stderr, "remove(\"%s\"): %s\n", fullname,
2642
/* need to clean even if 0 because man page doesn't specify */
2644
if(numentries == -1){
2645
perror_plus("scandir");
2647
ret = rmdir(tempdir);
2648
if(ret == -1 and errno != ENOENT){
2649
perror_plus("rmdir");
3110
clean_dir_at(-1, tempdir, 0);