/mandos/trunk : revision 359

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

82

#include <signal.h> /* sigemptyset(), sigaddset(),

83

sigaction(), SIGTERM, sig_atomic_t,

84

raise() */

85

#include <sysexits.h> /* EX_OSERR, EX_USAGE */

86

85

87

86

#ifdef __linux__

88

87

#include <sys/klog.h> /* klogctl() */

143

142

.dh_bits = 1024, .priority = "SECURE256"

144

143

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

145

144

146

sig_atomic_t quit_now = 0;

147

int signal_received = 0;

148

149

145

/*

150

146

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

151

147

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

168

164

*/

169

165

static bool init_gpgme(const char *seckey,

170

166

const char *pubkey, const char *tempdir){

167

int ret;

171

168

gpgme_error_t rc;

172

169

gpgme_engine_info_t engine_info;

173

170

176

173

* Helper function to insert pub and seckey to the engine keyring.

177

174

*/

178

175

bool import_key(const char *filename){

179

int ret;

180

176

int fd;

181

177

gpgme_data_t pgp_data;

182

178

478

474

static int init_gnutls_session(gnutls_session_t *session){

479

475

int ret;

480

476

/* GnuTLS session creation */

481

do {

482

ret = gnutls_init(session, GNUTLS_SERVER);

483

if(quit_now){

484

return -1;

485

}

486

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

477

ret = gnutls_init(session, GNUTLS_SERVER);

487

478

if(ret != GNUTLS_E_SUCCESS){

488

479

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

489

480

safer_gnutls_strerror(ret));

491

482

492

483

{

493

484

const char *err;

494

do {

495

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

496

if(quit_now){

497

gnutls_deinit(*session);

498

return -1;

499

}

500

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

485

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

501

486

if(ret != GNUTLS_E_SUCCESS){

502

487

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

503

488

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

507

492

}

508

493

}

509

494

510

do {

511

ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,

512

mc.cred);

513

if(quit_now){

514

gnutls_deinit(*session);

515

return -1;

516

}

517

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

495

ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,

496

mc.cred);

518

497

if(ret != GNUTLS_E_SUCCESS){

519

498

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

520

499

safer_gnutls_strerror(ret));

523

502

}

524

503

525

504

/* ignore client certificate if any. */

526

gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);

505

gnutls_certificate_server_set_request(*session,

506

GNUTLS_CERT_IGNORE);

527

507

528

508

gnutls_dh_set_prime_bits(*session, mc.dh_bits);

529

509

534

514

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

535

515

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

536

516

517

sig_atomic_t quit_now = 0;

518

int signal_received = 0;

519

537

520

/* Called when a Mandos server is found */

538

521

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

539

522

AvahiIfIndex if_index,

545

528

struct sockaddr_in6 in6;

546

529

} to;

547

530

char *buffer = NULL;

548

char *decrypted_buffer = NULL;

531

char *decrypted_buffer;

549

532

size_t buffer_length = 0;

550

533

size_t buffer_capacity = 0;

534

ssize_t decrypted_buffer_size;

551

535

size_t written;

552

int retval = -1;

536

int retval = 0;

553

537

gnutls_session_t session;

554

538

int pf; /* Protocol family */

555

539

582

566

tcp_sd = socket(pf, SOCK_STREAM, 0);

583

567

if(tcp_sd < 0){

584

568

perror("socket");

569

retval = -1;

585

570

goto mandos_end;

586

571

}

587

572

599

584

}

600

585

if(ret < 0 ){

601

586

perror("inet_pton");

587

retval = -1;

602

588

goto mandos_end;

603

589

}

604

590

if(ret == 0){

605

591

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

592

retval = -1;

606

593

goto mandos_end;

607

594

}

608

595

if(af == AF_INET6){

616

603

if(if_index == AVAHI_IF_UNSPEC){

617

604

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

618

605

" without a network interface\n");

606

retval = -1;

619

607

goto mandos_end;

620

608

}

621

609

/* Set the network interface number as scope */

674

662

}

675

663

if(ret < 0){

676

664

perror("connect");

665

retval = -1;

677

666

goto mandos_end;

678

667

}

679

668

689

678

out_size - written));

690

679

if(ret == -1){

691

680

perror("write");

681

retval = -1;

692

682

goto mandos_end;

693

683

}

694

684

written += (size_t)ret;

722

712

goto mandos_end;

723

713

}

724

714

725

do {

715

do{

726

716

ret = gnutls_handshake(session);

727

717

if(quit_now){

728

718

goto mandos_end;

734

724

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

735

725

gnutls_perror(ret);

736

726

}

727

retval = -1;

737

728

goto mandos_end;

738

729

}

739

730

754

745

buffer_capacity);

755

746

if(buffer_capacity == 0){

756

747

perror("incbuffer");

748

retval = -1;

757

749

goto mandos_end;

758

750

}

759

751

772

764

case GNUTLS_E_AGAIN:

773

765

break;

774

766

case GNUTLS_E_REHANDSHAKE:

775

do {

767

do{

776

768

ret = gnutls_handshake(session);

777

769

778

770

if(quit_now){

782

774

if(ret < 0){

783

775

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

784

776

gnutls_perror(ret);

777

retval = -1;

785

778

goto mandos_end;

786

779

}

787

780

break;

788

781

default:

789

782

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

790

783

" encrypted session with Mandos server\n");

784

retval = -1;

791

785

gnutls_bye(session, GNUTLS_SHUT_RDWR);

792

786

goto mandos_end;

793

787

}

804

798

goto mandos_end;

805

799

}

806

800

807

do {

808

ret = gnutls_bye(session, GNUTLS_SHUT_RDWR);

809

if(quit_now){

810

goto mandos_end;

811

}

812

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

801

gnutls_bye(session, GNUTLS_SHUT_RDWR);

802

803

if(quit_now){

804

goto mandos_end;

805

}

813

806

814

807

if(buffer_length > 0){

815

ssize_t decrypted_buffer_size;

816

808

decrypted_buffer_size = pgp_packet_decrypt(buffer,

817

809

buffer_length,

818

810

&decrypted_buffer);

819

811

if(decrypted_buffer_size >= 0){

820

821

812

written = 0;

822

813

while(written < (size_t) decrypted_buffer_size){

823

814

if(quit_now){

832

823

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

833

824

strerror(errno));

834

825

}

835

goto mandos_end;

826

retval = -1;

827

break;

836

828

}

837

829

written += (size_t)ret;

838

830

}

839

retval = 0;

831

free(decrypted_buffer);

832

} else {

833

retval = -1;

840

834

}

835

} else {

836

retval = -1;

841

837

}

842

838

843

839

/* Shutdown procedure */

844

840

845

841

mandos_end:

846

free(decrypted_buffer);

847

842

free(buffer);

848

843

if(tcp_sd >= 0){

849

844

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

999

994

bool gpgme_initialized = false;

1000

995

float delay = 2.5f;

1001

996

1002

struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };

997

struct sigaction old_sigterm_action;

1003

998

struct sigaction sigterm_action = { .sa_handler = handle_sigterm };

1004

999

1005

uid = getuid();

1006

gid = getgid();

1007

1008

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

1009

errno = 0;

1010

ret = setgid(gid);

1011

if(ret == -1){

1012

perror("setgid");

1013

}

1014

1015

/* Lower user privileges (temporarily) */

1016

errno = 0;

1017

ret = seteuid(uid);

1018

if(ret == -1){

1019

perror("seteuid");

1020

}

1021

1022

if(quit_now){

1023

goto end;

1024

}

1025

1026

1000

{

1027

1001

struct argp_option options[] = {

1028

1002

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

1057

1031

.arg = "SECONDS",

1058

1032

.doc = "Maximum delay to wait for interface startup",

1059

1033

.group = 2 },

1060

/*

1061

* These reproduce what we would get without ARGP_NO_HELP

1062

*/

1063

{ .name = "help", .key = '?',

1064

.doc = "Give this help list", .group = -1 },

1065

{ .name = "usage", .key = -3,

1066

.doc = "Give a short usage message", .group = -1 },

1067

{ .name = "version", .key = 'V',

1068

.doc = "Print program version", .group = -1 },

1069

1034

{ .name = NULL }

1070

1035

};

1071

1036

1072

1037

error_t parse_opt(int key, char *arg,

1073

1038

struct argp_state *state){

1074

errno = 0;

1075

1039

switch(key){

1076

1040

case 128: /* --debug */

1077

1041

debug = true;

1093

1057

tmpmax = strtoimax(arg, &tmp, 10);

1094

1058

if(errno != 0 or tmp == arg or *tmp != '\0'

1095

1059

or tmpmax != (typeof(mc.dh_bits))tmpmax){

1096

argp_error(state, "Bad number of DH bits");

1060

fprintf(stderr, "Bad number of DH bits\n");

1061

exit(EXIT_FAILURE);

1097

1062

}

1098

1063

mc.dh_bits = (typeof(mc.dh_bits))tmpmax;

1099

1064

break;

1104

1069

errno = 0;

1105

1070

delay = strtof(arg, &tmp);

1106

1071

if(errno != 0 or tmp == arg or *tmp != '\0'){

1107

argp_error(state, "Bad delay");

1072

fprintf(stderr, "Bad delay\n");

1073

exit(EXIT_FAILURE);

1108

1074

}

1109

1075

break;

1110

/*

1111

* These reproduce what we would get without ARGP_NO_HELP

1112

*/

1113

case '?': /* --help */

1114

argp_state_help(state, state->out_stream,

1115

(ARGP_HELP_STD_HELP | ARGP_HELP_EXIT_ERR)

1116

& ~(unsigned int)ARGP_HELP_EXIT_OK);

1117

case -3: /* --usage */

1118

argp_state_help(state, state->out_stream,

1119

ARGP_HELP_USAGE | ARGP_HELP_EXIT_ERR);

1120

case 'V': /* --version */

1121

fprintf(state->out_stream, "%s\n", argp_program_version);

1122

exit(argp_err_exit_status);

1076

case ARGP_KEY_ARG:

1077

argp_usage(state);

1078

case ARGP_KEY_END:

1123

1079

break;

1124

1080

default:

1125

1081

return ARGP_ERR_UNKNOWN;

1126

1082

}

1127

return errno;

1083

return 0;

1128

1084

}

1129

1085

1130

1086

struct argp argp = { .options = options, .parser = parse_opt,

1131

1087

.args_doc = "",

1132

1088

.doc = "Mandos client -- Get and decrypt"

1133

1089

" passwords from a Mandos server" };

1134

ret = argp_parse(&argp, argc, argv,

1135

ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);

1136

switch(ret){

1137

case 0:

1138

break;

1139

case ENOMEM:

1140

default:

1141

errno = ret;

1142

perror("argp_parse");

1143

exitcode = EX_OSERR;

1144

goto end;

1145

case EINVAL:

1146

exitcode = EX_USAGE;

1090

ret = argp_parse(&argp, argc, argv, 0, 0, NULL);

1091

if(ret == ARGP_ERR_UNKNOWN){

1092

fprintf(stderr, "Unknown error while parsing arguments\n");

1093

exitcode = EXIT_FAILURE;

1147

1094

goto end;

1148

1095

}

1149

1096

}

1239

1186

goto end;

1240

1187

}

1241

1188

1242

/* Re-raise priviliges */

1243

errno = 0;

1244

ret = seteuid(0);

1245

if(ret == -1){

1246

perror("seteuid");

1247

}

1248

1249

1189

#ifdef __linux__

1250

1190

/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO

1251

messages about the network interface to mess up the prompt */

1191

messages to mess up the prompt */

1252

1192

ret = klogctl(8, NULL, 5);

1253

1193

bool restore_loglevel = true;

1254

1194

if(ret == -1){

1269

1209

}

1270

1210

}

1271

1211

#endif /* __linux__ */

1272

/* Lower privileges */

1273

errno = 0;

1274

ret = seteuid(uid);

1275

if(ret == -1){

1276

perror("seteuid");

1277

}

1278

1212

goto end;

1279

1213

}

1280

1214

strcpy(network.ifr_name, interface);

1290

1224

}

1291

1225

#endif /* __linux__ */

1292

1226

exitcode = EXIT_FAILURE;

1293

/* Lower privileges */

1294

errno = 0;

1295

ret = seteuid(uid);

1296

if(ret == -1){

1297

perror("seteuid");

1298

}

1299

1227

goto end;

1300

1228

}

1301

1229

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

1314

1242

}

1315

1243

}

1316

1244

#endif /* __linux__ */

1317

/* Lower privileges */

1318

errno = 0;

1319

ret = seteuid(uid);

1320

if(ret == -1){

1321

perror("seteuid");

1322

}

1323

1245

goto end;

1324

1246

}

1325

1247

}

1353

1275

}

1354

1276

}

1355

1277

#endif /* __linux__ */

1356

/* Lower privileges */

1357

errno = 0;

1358

if(take_down_interface){

1359

/* Lower privileges */

1360

ret = seteuid(uid);

1361

if(ret == -1){

1362

perror("seteuid");

1363

}

1364

} else {

1365

/* Lower privileges permanently */

1366

ret = setuid(uid);

1367

if(ret == -1){

1368

perror("setuid");

1369

}

1370

}

1278

}

1279

1280

if(quit_now){

1281

goto end;

1282

}

1283

1284

uid = getuid();

1285

gid = getgid();

1286

1287

errno = 0;

1288

setgid(gid);

1289

if(ret == -1){

1290

perror("setgid");

1291

}

1292

1293

ret = setuid(uid);

1294

if(ret == -1){

1295

perror("setuid");

1371

1296

}

1372

1297

1373

1298

if(quit_now){

1547

1472

1548

1473

/* Take down the network interface */

1549

1474

if(take_down_interface){

1550

/* Re-raise priviliges */

1551

errno = 0;

1552

ret = seteuid(0);

1475

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

1553

1476

if(ret == -1){

1554

perror("seteuid");

1477

perror("ioctl SIOCGIFFLAGS");

1478

} else if(network.ifr_flags & IFF_UP) {

1479

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

1480

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

1481

if(ret == -1){

1482

perror("ioctl SIOCSIFFLAGS");

1483

}

1555

1484

}

1556

if(geteuid() == 0){

1557

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

1558

if(ret == -1){

1559

perror("ioctl SIOCGIFFLAGS");

1560

} else if(network.ifr_flags & IFF_UP) {

1561

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

1562

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

1563

if(ret == -1){

1564

perror("ioctl SIOCSIFFLAGS");

1565

}

1566

}

1567

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

1568

if(ret == -1){

1569

perror("close");

1570

}

1571

/* Lower privileges permanently */

1572

errno = 0;

1573

ret = setuid(uid);

1574

if(ret == -1){

1575

perror("setuid");

1576

}

1485

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

1486

if(ret == -1){

1487

perror("close");

1577

1488

}

1578

1489

}

1579

1490

1624

1535

if(quit_now){

1625

1536

sigemptyset(&old_sigterm_action.sa_mask);

1626

1537

old_sigterm_action.sa_handler = SIG_DFL;

1627

ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,

1628

&old_sigterm_action,

1629

NULL));

1538

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

1630

1539

if(ret == -1){

1631

1540

perror("sigaction");

1632

1541

}

1633

do {

1634

ret = raise(signal_received);

1635

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

1636

if(ret != 0){

1637

perror("raise");

1638

abort();

1639

}

1640

TEMP_FAILURE_RETRY(pause());

1542

raise(signal_received);

1641

1543

}

1642

1544

1643

1545

return exitcode;