/mandos/trunk : revision 24.1.140

44

#include <stdint.h> /* uint16_t, uint32_t */

45

#include <stddef.h> /* NULL, size_t, ssize_t */

46

#include <stdlib.h> /* free(), EXIT_SUCCESS, EXIT_FAILURE,

47

srand(), strtof(), abort() */

47

srand(), strtof() */

48

#include <stdbool.h> /* bool, false, true */

49

#include <string.h> /* memset(), strcmp(), strlen(),

50

strerror(), asprintf(), strcpy() */

71

INET_ADDRSTRLEN, INET6_ADDRSTRLEN

72

*/

73

#include <unistd.h> /* close(), SEEK_SET, off_t, write(),

74

getuid(), getgid(), seteuid(),

75

setgid(), pause() */

74

getuid(), getgid(), setuid(),

75

setgid() */

76

#include <arpa/inet.h> /* inet_pton(), htons */

77

#include <iso646.h> /* not, or, and */

78

#include <argp.h> /* struct argp_option, error_t, struct

125

static const char mandos_protocol_version[] = "1";

126

const char *argp_program_version = "mandos-client " VERSION;

127

const char *argp_program_bug_address = "<mandos@fukt.bsnet.se>";

128

static const char sys_class_net[] = "/sys/class/net";

129

char *connect_to = NULL;

130

128

131

129

/* Used for passing in values through the Avahi callback functions */

132

130

typedef struct {

144

142

.dh_bits = 1024, .priority = "SECURE256"

145

143

":!CTYPE-X.509:+CTYPE-OPENPGP" };

146

144

147

sig_atomic_t quit_now = 0;

148

int signal_received = 0;

149

150

145

/*

151

146

* Make additional room in "buffer" for at least BUFFER_SIZE more

152

147

* bytes. "buffer_capacity" is how much is currently allocated,

479

474

static int init_gnutls_session(gnutls_session_t *session){

480

475

int ret;

481

476

/* GnuTLS session creation */

482

do {

483

ret = gnutls_init(session, GNUTLS_SERVER);

484

if(quit_now){

485

return -1;

486

}

487

} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);

477

ret = gnutls_init(session, GNUTLS_SERVER);

488

478

if(ret != GNUTLS_E_SUCCESS){

489

479

fprintf(stderr, "Error in GnuTLS session initialization: %s\n",

490

480

safer_gnutls_strerror(ret));

492

482

493

483

{

494

484

const char *err;

495

do {

496

ret = gnutls_priority_set_direct(*session, mc.priority, &err);

497

if(quit_now){

498

gnutls_deinit(*session);

499

return -1;

500

}

501

} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);

485

ret = gnutls_priority_set_direct(*session, mc.priority, &err);

502

486

if(ret != GNUTLS_E_SUCCESS){

503

487

fprintf(stderr, "Syntax error at: %s\n", err);

504

488

fprintf(stderr, "GnuTLS error: %s\n",

508

492

}

509

493

}

510

494

511

do {

512

ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,

513

mc.cred);

514

if(quit_now){

515

gnutls_deinit(*session);

516

return -1;

517

}

518

} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);

495

ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,

496

mc.cred);

519

497

if(ret != GNUTLS_E_SUCCESS){

520

498

fprintf(stderr, "Error setting GnuTLS credentials: %s\n",

521

499

safer_gnutls_strerror(ret));

524

502

}

525

503

526

504

/* ignore client certificate if any. */

527

gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);

505

gnutls_certificate_server_set_request(*session,

506

GNUTLS_CERT_IGNORE);

528

507

529

508

gnutls_dh_set_prime_bits(*session, mc.dh_bits);

530

509

535

514

static void empty_log(__attribute__((unused)) AvahiLogLevel level,

536

515

__attribute__((unused)) const char *txt){}

537

516

517

sig_atomic_t quit_now = 0;

518

int signal_received = 0;

519

538

520

/* Called when a Mandos server is found */

539

521

static int start_mandos_communication(const char *ip, uint16_t port,

540

522

AvahiIfIndex if_index,

546

528

struct sockaddr_in6 in6;

547

529

} to;

548

530

char *buffer = NULL;

549

char *decrypted_buffer = NULL;

531

char *decrypted_buffer;

550

532

size_t buffer_length = 0;

551

533

size_t buffer_capacity = 0;

552

534

size_t written;

553

int retval = -1;

535

int retval = 0;

554

536

gnutls_session_t session;

555

537

int pf; /* Protocol family */

556

538

583

565

tcp_sd = socket(pf, SOCK_STREAM, 0);

584

566

if(tcp_sd < 0){

585

567

perror("socket");

568

retval = -1;

586

569

goto mandos_end;

587

570

}

588

571

600

583

}

601

584

if(ret < 0 ){

602

585

perror("inet_pton");

586

retval = -1;

603

587

goto mandos_end;

604

588

}

605

589

if(ret == 0){

606

590

fprintf(stderr, "Bad address: %s\n", ip);

591

retval = -1;

607

592

goto mandos_end;

608

593

}

609

594

if(af == AF_INET6){

617

602

if(if_index == AVAHI_IF_UNSPEC){

618

603

fprintf(stderr, "An IPv6 link-local address is incomplete"

619

604

" without a network interface\n");

605

retval = -1;

620

606

goto mandos_end;

621

607

}

622

608

/* Set the network interface number as scope */

675

661

}

676

662

if(ret < 0){

677

663

perror("connect");

664

retval = -1;

678

665

goto mandos_end;

679

666

}

680

667

690

677

out_size - written));

691

678

if(ret == -1){

692

679

perror("write");

680

retval = -1;

693

681

goto mandos_end;

694

682

}

695

683

written += (size_t)ret;

735

723

fprintf(stderr, "*** GnuTLS Handshake failed ***\n");

736

724

gnutls_perror(ret);

737

725

}

726

retval = -1;

738

727

goto mandos_end;

739

728

}

740

729

755

744

buffer_capacity);

756

745

if(buffer_capacity == 0){

757

746

perror("incbuffer");

747

retval = -1;

758

748

goto mandos_end;

759

749

}

760

750

783

773

if(ret < 0){

784

774

fprintf(stderr, "*** GnuTLS Re-handshake failed ***\n");

785

775

gnutls_perror(ret);

776

retval = -1;

786

777

goto mandos_end;

787

778

}

788

779

break;

789

780

default:

790

781

fprintf(stderr, "Unknown error while reading data from"

791

782

" encrypted session with Mandos server\n");

783

retval = -1;

792

784

gnutls_bye(session, GNUTLS_SHUT_RDWR);

793

785

goto mandos_end;

794

786

}

805

797

goto mandos_end;

806

798

}

807

799

808

do {

809

ret = gnutls_bye(session, GNUTLS_SHUT_RDWR);

810

if(quit_now){

811

goto mandos_end;

812

}

813

} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);

800

gnutls_bye(session, GNUTLS_SHUT_RDWR);

801

802

if(quit_now){

803

goto mandos_end;

804

}

814

805

815

806

if(buffer_length > 0){

816

807

ssize_t decrypted_buffer_size;

833

824

fprintf(stderr, "Error writing encrypted data: %s\n",

834

825

strerror(errno));

835

826

}

836

goto mandos_end;

827

retval = -1;

828

break;

837

829

}

838

830

written += (size_t)ret;

839

831

}

840

retval = 0;

832

free(decrypted_buffer);

833

} else {

834

retval = -1;

841

835

}

836

} else {

837

retval = -1;

842

838

}

843

839

844

840

/* Shutdown procedure */

845

841

846

842

mandos_end:

847

free(decrypted_buffer);

848

843

free(buffer);

849

844

if(tcp_sd >= 0){

850

845

ret = (int)TEMP_FAILURE_RETRY(close(tcp_sd));

976

971

errno = old_errno;

977

972

}

978

973

979

/*

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.)

983

*/

984

int good_interface(const struct dirent *if_entry){

985

ssize_t ssret;

986

char *flagname = NULL;

987

int ret = asprintf(&flagname, "%s/%s/flags", sys_class_net,

988

if_entry->d_name);

989

if(ret < 0){

990

perror("asprintf");

991

return 0;

992

}

993

if(if_entry->d_name[0] == '.'){

994

return 0;

995

}

996

int flags_fd = (int)TEMP_FAILURE_RETRY(open(flagname, O_RDONLY));

997

if(flags_fd == -1){

998

perror("open");

999

return 0;

1000

}

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){

1006

perror("malloc");

1007

close(flags_fd);

1008

return 0;

1009

}

1010

while(to_read > 0){

1011

ssret = (ssize_t)TEMP_FAILURE_RETRY(read(flags_fd, flagstring,

1012

(size_t)to_read));

1013

if(ssret == -1){

1014

perror("read");

1015

free(flagstring);

1016

close(flags_fd);

1017

return 0;

1018

}

1019

to_read -= ssret;

1020

if(ssret == 0){

1021

break;

1022

}

1023

}

1024

close(flags_fd);

1025

intmax_t tmpmax;

1026

char *tmp;

1027

errno = 0;

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){

1032

free(flagstring);

1033

return 0;

1034

}

1035

free(flagstring);

1036

ifreq_flags flags = (ifreq_flags)tmpmax;

1037

/* Reject the loopback device */

1038

if(flags & IFF_LOOPBACK){

1039

return 0;

1040

}

1041

/* Accept point-to-point devices only if connect_to is specified */

1042

if(connect_to != NULL and (flags & IFF_POINTOPOINT)){

1043

return 1;

1044

}

1045

/* Otherwise, reject non-broadcast-capable devices */

1046

if(not (flags & IFF_BROADCAST)){

1047

return 0;

1048

}

1049

/* Accept this device */

1050

return 1;

1051

}

1052

1053

974

int main(int argc, char *argv[]){

1054

975

AvahiSServiceBrowser *sb = NULL;

1055

976

int error;

1057

978

intmax_t tmpmax;

1058

979

char *tmp;

1059

980

int exitcode = EXIT_SUCCESS;

1060

const char *interface = "";

981

const char *interface = "eth0";

1061

982

struct ifreq network;

1062

983

int sd = -1;

1063

984

bool take_down_interface = false;

1064

985

uid_t uid;

1065

986

gid_t gid;

987

char *connect_to = NULL;

1066

988

char tempdir[] = "/tmp/mandosXXXXXX";

1067

989

bool tempdir_created = false;

1068

990

AvahiIfIndex if_index = AVAHI_IF_UNSPEC;

1073

995

bool gpgme_initialized = false;

1074

996

float delay = 2.5f;

1075

997

1076

struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };

998

struct sigaction old_sigterm_action;

1077

999

struct sigaction sigterm_action = { .sa_handler = handle_sigterm };

1078

1000

1079

uid = getuid();

1080

gid = getgid();

1081

1082

/* Lower any group privileges we might have, just to be safe */

1083

errno = 0;

1084

ret = setgid(gid);

1085

if(ret == -1){

1086

perror("setgid");

1087

}

1088

1089

/* Lower user privileges (temporarily) */

1090

errno = 0;

1091

ret = seteuid(uid);

1092

if(ret == -1){

1093

perror("seteuid");

1094

}

1095

1096

if(quit_now){

1097

goto end;

1098

}

1099

1100

1001

{

1101

1002

struct argp_option options[] = {

1102

1003

{ .name = "debug", .key = 128,

1198

1099

if(not debug){

1199

1100

avahi_set_log_function(empty_log);

1200

1101

}

1201

1202

if(interface[0] == '\0'){

1203

struct dirent **direntries;

1204

ret = scandir(sys_class_net, &direntries, good_interface,

1205

alphasort);

1206

if(ret >= 1){

1207

/* Pick the first good interface */

1208

interface = strdup(direntries[0]->d_name);

1209

if(interface == NULL){

1210

perror("malloc");

1211

free(direntries);

1212

exitcode = EXIT_FAILURE;

1213

goto end;

1214

}

1215

free(direntries);

1216

} else {

1217

free(direntries);

1218

fprintf(stderr, "Could not find a network interface\n");

1219

exitcode = EXIT_FAILURE;

1220

goto end;

1221

}

1222

}

1223

1102

1224

1103

/* Initialize Avahi early so avahi_simple_poll_quit() can be called

1225

1104

from the signal handler */

1296

1175

}

1297

1176

1298

1177

/* If the interface is down, bring it up */

1299

if(strcmp(interface, "none") != 0){

1178

if(interface[0] != '\0'){

1300

1179

if_index = (AvahiIfIndex) if_nametoindex(interface);

1301

1180

if(if_index == 0){

1302

1181

fprintf(stderr, "No such interface: \"%s\"\n", interface);

1308

1187

goto end;

1309

1188

}

1310

1189

1311

/* Re-raise priviliges */

1312

errno = 0;

1313

ret = seteuid(0);

1314

if(ret == -1){

1315

perror("seteuid");

1316

}

1317

1318

1190

#ifdef __linux__

1319

1191

/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO

1320

1192

messages to mess up the prompt */

1338

1210

}

1339

1211

}

1340

1212

#endif /* __linux__ */

1341

/* Lower privileges */

1342

errno = 0;

1343

ret = seteuid(uid);

1344

if(ret == -1){

1345

perror("seteuid");

1346

}

1347

1213

goto end;

1348

1214

}

1349

1215

strcpy(network.ifr_name, interface);

1359

1225

}

1360

1226

#endif /* __linux__ */

1361

1227

exitcode = EXIT_FAILURE;

1362

/* Lower privileges */

1363

errno = 0;

1364

ret = seteuid(uid);

1365

if(ret == -1){

1366

perror("seteuid");

1367

}

1368

1228

goto end;

1369

1229

}

1370

1230

if((network.ifr_flags & IFF_UP) == 0){

1383

1243

}

1384

1244

}

1385

1245

#endif /* __linux__ */

1386

/* Lower privileges */

1387

errno = 0;

1388

ret = seteuid(uid);

1389

if(ret == -1){

1390

perror("seteuid");

1391

}

1392

1246

goto end;

1393

1247

}

1394

1248

}

1422

1276

}

1423

1277

}

1424

1278

#endif /* __linux__ */

1425

/* Lower privileges */

1426

errno = 0;

1427

if(take_down_interface){

1428

/* Lower privileges */

1429

ret = seteuid(uid);

1430

if(ret == -1){

1431

perror("seteuid");

1432

}

1433

} else {

1434

/* Lower privileges permanently */

1435

ret = setuid(uid);

1436

if(ret == -1){

1437

perror("setuid");

1438

}

1439

}

1279

}

1280

1281

if(quit_now){

1282

goto end;

1283

}

1284

1285

uid = getuid();

1286

gid = getgid();

1287

1288

errno = 0;

1289

setgid(gid);

1290

if(ret == -1){

1291

perror("setgid");

1292

}

1293

1294

ret = setuid(uid);

1295

if(ret == -1){

1296

perror("setuid");

1440

1297

}

1441

1298

1442

1299

if(quit_now){

1616

1473

1617

1474

/* Take down the network interface */

1618

1475

if(take_down_interface){

1619

/* Re-raise priviliges */

1620

errno = 0;

1621

ret = seteuid(0);

1476

ret = ioctl(sd, SIOCGIFFLAGS, &network);

1622

1477

if(ret == -1){

1623

perror("seteuid");

1478

perror("ioctl SIOCGIFFLAGS");

1479

} else if(network.ifr_flags & IFF_UP) {

1480

network.ifr_flags &= ~IFF_UP; /* clear flag */

1481

ret = ioctl(sd, SIOCSIFFLAGS, &network);

1482

if(ret == -1){

1483

perror("ioctl SIOCSIFFLAGS");

1484

}

1624

1485

}

1625

if(geteuid() == 0){

1626

ret = ioctl(sd, SIOCGIFFLAGS, &network);

1627

if(ret == -1){

1628

perror("ioctl SIOCGIFFLAGS");

1629

} else if(network.ifr_flags & IFF_UP) {

1630

network.ifr_flags &= ~IFF_UP; /* clear flag */

1631

ret = ioctl(sd, SIOCSIFFLAGS, &network);

1632

if(ret == -1){

1633

perror("ioctl SIOCSIFFLAGS");

1634

}

1635

}

1636

ret = (int)TEMP_FAILURE_RETRY(close(sd));

1637

if(ret == -1){

1638

perror("close");

1639

}

1640

/* Lower privileges permanently */

1641

errno = 0;

1642

ret = setuid(uid);

1643

if(ret == -1){

1644

perror("setuid");

1645

}

1486

ret = (int)TEMP_FAILURE_RETRY(close(sd));

1487

if(ret == -1){

1488

perror("close");

1646

1489

}

1647

1490

}

1648

1491

1693

1536

if(quit_now){

1694

1537

sigemptyset(&old_sigterm_action.sa_mask);

1695

1538

old_sigterm_action.sa_handler = SIG_DFL;

1696

ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,

1697

&old_sigterm_action,

1698

NULL));

1539

ret = sigaction(signal_received, &old_sigterm_action, NULL);

1699

1540

if(ret == -1){

1700

1541

perror("sigaction");

1701

1542

}

1702

do {

1703

ret = raise(signal_received);

1704

} while(ret != 0 and errno == EINTR);

1705

if(ret != 0){

1706

perror("raise");

1707

abort();

1708

}

1709

TEMP_FAILURE_RETRY(pause());

1543

raise(signal_received);

1710

1544

}

1711

1545

1712

1546

return exitcode;