/mandos/trunk : revision 396

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() */

47

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

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(), setuid(),

75

setgid() */

74

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

75

setgid(), pause() */

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 */

85

86

87

#ifdef __linux__

87

88

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

142

143

.dh_bits = 1024, .priority = "SECURE256"

143

144

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

144

145

146

sig_atomic_t quit_now = 0;

147

int signal_received = 0;

148

145

149

/*

146

150

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

147

151

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

164

168

*/

165

169

static bool init_gpgme(const char *seckey,

166

170

const char *pubkey, const char *tempdir){

167

int ret;

168

171

gpgme_error_t rc;

169

172

gpgme_engine_info_t engine_info;

170

173

176

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

174

177

*/

175

178

bool import_key(const char *filename){

179

int ret;

176

180

int fd;

177

181

gpgme_data_t pgp_data;

178

182

474

478

static int init_gnutls_session(gnutls_session_t *session){

475

479

int ret;

476

480

/* GnuTLS session creation */

477

ret = gnutls_init(session, GNUTLS_SERVER);

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);

478

487

if(ret != GNUTLS_E_SUCCESS){

479

488

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

480

489

safer_gnutls_strerror(ret));

482

491

483

492

{

484

493

const char *err;

485

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

486

501

if(ret != GNUTLS_E_SUCCESS){

487

502

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

488

503

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

492

507

}

493

508

}

494

509

495

ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,

496

mc.cred);

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);

497

518

if(ret != GNUTLS_E_SUCCESS){

498

519

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

499

520

safer_gnutls_strerror(ret));

502

523

}

503

524

504

525

/* ignore client certificate if any. */

505

gnutls_certificate_server_set_request(*session,

506

GNUTLS_CERT_IGNORE);

526

gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);

507

527

508

528

gnutls_dh_set_prime_bits(*session, mc.dh_bits);

509

529

514

534

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

515

535

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

516

536

517

sig_atomic_t quit_now = 0;

518

int signal_received = 0;

519

520

537

/* Called when a Mandos server is found */

521

538

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

522

539

AvahiIfIndex if_index,

523

540

int af){

524

int ret, tcp_sd;

541

int ret, tcp_sd = -1;

525

542

ssize_t sret;

526

543

union {

527

544

struct sockaddr_in in;

528

545

struct sockaddr_in6 in6;

529

546

} to;

530

547

char *buffer = NULL;

531

char *decrypted_buffer;

548

char *decrypted_buffer = NULL;

532

549

size_t buffer_length = 0;

533

550

size_t buffer_capacity = 0;

534

ssize_t decrypted_buffer_size;

535

551

size_t written;

536

int retval = 0;

552

int retval = -1;

537

553

gnutls_session_t session;

538

554

int pf; /* Protocol family */

539

555

556

if(quit_now){

557

return -1;

558

}

559

540

560

switch(af){

541

561

case AF_INET6:

542

562

pf = PF_INET6;

562

582

tcp_sd = socket(pf, SOCK_STREAM, 0);

563

583

if(tcp_sd < 0){

564

584

perror("socket");

565

return -1;

585

goto mandos_end;

586

}

587

588

if(quit_now){

589

goto mandos_end;

566

590

}

567

591

568

592

memset(&to, 0, sizeof(to));

575

599

}

576

600

if(ret < 0 ){

577

601

perror("inet_pton");

578

return -1;

602

goto mandos_end;

579

603

}

580

604

if(ret == 0){

581

605

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

582

return -1;

606

goto mandos_end;

583

607

}

584

608

if(af == AF_INET6){

585

609

to.in6.sin6_port = htons(port); /* Spurious warnings from

592

616

if(if_index == AVAHI_IF_UNSPEC){

593

617

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

594

618

" without a network interface\n");

595

return -1;

619

goto mandos_end;

596

620

}

597

621

/* Set the network interface number as scope */

598

622

to.in6.sin6_scope_id = (uint32_t)if_index;

603

627

-Wunreachable-code */

604

628

}

605

629

630

if(quit_now){

631

goto mandos_end;

632

}

633

606

634

if(debug){

607

635

if(af == AF_INET6 and if_index != AVAHI_IF_UNSPEC){

608

636

char interface[IF_NAMESIZE];

635

663

}

636

664

}

637

665

666

if(quit_now){

667

goto mandos_end;

668

}

669

638

670

if(af == AF_INET6){

639

671

ret = connect(tcp_sd, &to.in6, sizeof(to));

640

672

} else {

642

674

}

643

675

if(ret < 0){

644

676

perror("connect");

645

return -1;

677

goto mandos_end;

678

}

679

680

if(quit_now){

681

goto mandos_end;

646

682

}

647

683

648

684

const char *out = mandos_protocol_version;

653

689

out_size - written));

654

690

if(ret == -1){

655

691

perror("write");

656

retval = -1;

657

692

goto mandos_end;

658

693

}

659

694

written += (size_t)ret;

667

702

break;

668

703

}

669

704

}

705

706

if(quit_now){

707

goto mandos_end;

708

}

670

709

}

671

710

672

711

if(debug){

673

712

fprintf(stderr, "Establishing TLS session with %s\n", ip);

674

713

}

675

714

715

if(quit_now){

716

goto mandos_end;

717

}

718

676

719

gnutls_transport_set_ptr(session, (gnutls_transport_ptr_t) tcp_sd);

677

720

678

do{

721

if(quit_now){

722

goto mandos_end;

723

}

724

725

do {

679

726

ret = gnutls_handshake(session);

727

if(quit_now){

728

goto mandos_end;

729

}

680

730

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

681

731

682

732

if(ret != GNUTLS_E_SUCCESS){

684

734

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

685

735

gnutls_perror(ret);

686

736

}

687

retval = -1;

688

737

goto mandos_end;

689

738

}

690

739

696

745

}

697

746

698

747

while(true){

748

749

if(quit_now){

750

goto mandos_end;

751

}

752

699

753

buffer_capacity = incbuffer(&buffer, buffer_length,

700

754

buffer_capacity);

701

755

if(buffer_capacity == 0){

702

756

perror("incbuffer");

703

retval = -1;

757

goto mandos_end;

758

}

759

760

if(quit_now){

704

761

goto mandos_end;

705

762

}

706

763

715

772

case GNUTLS_E_AGAIN:

716

773

break;

717

774

case GNUTLS_E_REHANDSHAKE:

718

do{

775

do {

719

776

ret = gnutls_handshake(session);

777

778

if(quit_now){

779

goto mandos_end;

780

}

720

781

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

721

782

if(ret < 0){

722

783

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

723

784

gnutls_perror(ret);

724

retval = -1;

725

785

goto mandos_end;

726

786

}

727

787

break;

728

788

default:

729

789

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

730

790

" encrypted session with Mandos server\n");

731

retval = -1;

732

791

gnutls_bye(session, GNUTLS_SHUT_RDWR);

733

792

goto mandos_end;

734

793

}

741

800

fprintf(stderr, "Closing TLS session\n");

742

801

}

743

802

744

gnutls_bye(session, GNUTLS_SHUT_RDWR);

803

if(quit_now){

804

goto mandos_end;

805

}

806

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);

745

813

746

814

if(buffer_length > 0){

815

ssize_t decrypted_buffer_size;

747

816

decrypted_buffer_size = pgp_packet_decrypt(buffer,

748

817

buffer_length,

749

818

&decrypted_buffer);

750

819

if(decrypted_buffer_size >= 0){

820

751

821

written = 0;

752

822

while(written < (size_t) decrypted_buffer_size){

823

if(quit_now){

824

goto mandos_end;

825

}

826

753

827

ret = (int)fwrite(decrypted_buffer + written, 1,

754

828

(size_t)decrypted_buffer_size - written,

755

829

stdout);

758

832

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

759

833

strerror(errno));

760

834

}

761

retval = -1;

762

break;

835

goto mandos_end;

763

836

}

764

837

written += (size_t)ret;

765

838

}

766

free(decrypted_buffer);

767

} else {

768

retval = -1;

839

retval = 0;

769

840

}

770

} else {

771

retval = -1;

772

841

}

773

842

774

843

/* Shutdown procedure */

775

844

776

845

mandos_end:

846

free(decrypted_buffer);

777

847

free(buffer);

778

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

848

if(tcp_sd >= 0){

849

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

850

}

779

851

if(ret == -1){

780

852

perror("close");

781

853

}

782

854

gnutls_deinit(session);

855

if(quit_now){

856

retval = -1;

857

}

783

858

return retval;

784

859

}

785

860

848

923

/* Called whenever a new services becomes available on the LAN or

849

924

is removed from the LAN */

850

925

926

if(quit_now){

927

return;

928

}

929

851

930

switch(event){

852

931

default:

853

932

case AVAHI_BROWSER_FAILURE:

920

999

bool gpgme_initialized = false;

921

1000

float delay = 2.5f;

922

1001

923

struct sigaction old_sigterm_action;

1002

struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };

924

1003

struct sigaction sigterm_action = { .sa_handler = handle_sigterm };

925

1004

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

926

1026

{

927

1027

struct argp_option options[] = {

928

1028

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

957

1057

.arg = "SECONDS",

958

1058

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

959

1059

.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 },

960

1069

{ .name = NULL }

961

1070

};

962

1071

963

1072

error_t parse_opt(int key, char *arg,

964

1073

struct argp_state *state){

1074

errno = 0;

965

1075

switch(key){

966

1076

case 128: /* --debug */

967

1077

debug = true;

983

1093

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

984

1094

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

985

1095

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

986

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

987

exit(EXIT_FAILURE);

1096

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

988

1097

}

989

1098

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

990

1099

break;

995

1104

errno = 0;

996

1105

delay = strtof(arg, &tmp);

997

1106

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

998

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

999

exit(EXIT_FAILURE);

1107

argp_error(state, "Bad delay");

1000

1108

}

1001

1109

break;

1002

case ARGP_KEY_ARG:

1003

argp_usage(state);

1004

case ARGP_KEY_END:

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);

1005

1123

break;

1006

1124

default:

1007

1125

return ARGP_ERR_UNKNOWN;

1008

1126

}

1009

return 0;

1127

return errno;

1010

1128

}

1011

1129

1012

1130

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

1013

1131

.args_doc = "",

1014

1132

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

1015

1133

" passwords from a Mandos server" };

1016

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

1017

if(ret == ARGP_ERR_UNKNOWN){

1018

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

1019

exitcode = EXIT_FAILURE;

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;

1020

1147

goto end;

1021

1148

}

1022

1149

}

1055

1182

exitcode = EXIT_FAILURE;

1056

1183

goto end;

1057

1184

}

1058

ret = sigaction(SIGINT, &sigterm_action, &old_sigterm_action);

1059

if(ret == -1){

1060

perror("sigaction");

1061

exitcode = EXIT_FAILURE;

1062

goto end;

1063

}

1064

ret = sigaction(SIGHUP, &sigterm_action, NULL);

1065

if(ret == -1){

1066

perror("sigaction");

1067

exitcode = EXIT_FAILURE;

1068

goto end;

1069

}

1070

ret = sigaction(SIGTERM, &sigterm_action, NULL);

1071

if(ret == -1){

1072

perror("sigaction");

1073

exitcode = EXIT_FAILURE;

1074

goto end;

1185

/* Need to check if the handler is SIG_IGN before handling:

1186

| [[info:libc:Initial Signal Actions]] |

1187

| [[info:libc:Basic Signal Handling]] |

1188

*/

1189

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

1190

if(ret == -1){

1191

perror("sigaction");

1192

return EXIT_FAILURE;

1193

}

1194

if(old_sigterm_action.sa_handler != SIG_IGN){

1195

ret = sigaction(SIGINT, &sigterm_action, NULL);

1196

if(ret == -1){

1197

perror("sigaction");

1198

exitcode = EXIT_FAILURE;

1199

goto end;

1200

}

1201

}

1202

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

1203

if(ret == -1){

1204

perror("sigaction");

1205

return EXIT_FAILURE;

1206

}

1207

if(old_sigterm_action.sa_handler != SIG_IGN){

1208

ret = sigaction(SIGHUP, &sigterm_action, NULL);

1209

if(ret == -1){

1210

perror("sigaction");

1211

exitcode = EXIT_FAILURE;

1212

goto end;

1213

}

1214

}

1215

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

1216

if(ret == -1){

1217

perror("sigaction");

1218

return EXIT_FAILURE;

1219

}

1220

if(old_sigterm_action.sa_handler != SIG_IGN){

1221

ret = sigaction(SIGTERM, &sigterm_action, NULL);

1222

if(ret == -1){

1223

perror("sigaction");

1224

exitcode = EXIT_FAILURE;

1225

goto end;

1226

}

1075

1227

}

1076

1228

1077

1229

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

1087

1239

goto end;

1088

1240

}

1089

1241

1242

/* Re-raise priviliges */

1243

errno = 0;

1244

ret = seteuid(0);

1245

if(ret == -1){

1246

perror("seteuid");

1247

}

1248

1090

1249

#ifdef __linux__

1091

1250

/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO

1092

messages to mess up the prompt */

1251

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

1093

1252

ret = klogctl(8, NULL, 5);

1094

1253

bool restore_loglevel = true;

1095

1254

if(ret == -1){

1110

1269

}

1111

1270

}

1112

1271

#endif /* __linux__ */

1272

/* Lower privileges */

1273

errno = 0;

1274

ret = seteuid(uid);

1275

if(ret == -1){

1276

perror("seteuid");

1277

}

1113

1278

goto end;

1114

1279

}

1115

1280

strcpy(network.ifr_name, interface);

1125

1290

}

1126

1291

#endif /* __linux__ */

1127

1292

exitcode = EXIT_FAILURE;

1293

/* Lower privileges */

1294

errno = 0;

1295

ret = seteuid(uid);

1296

if(ret == -1){

1297

perror("seteuid");

1298

}

1128

1299

goto end;

1129

1300

}

1130

1301

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

1143

1314

}

1144

1315

}

1145

1316

#endif /* __linux__ */

1317

/* Lower privileges */

1318

errno = 0;

1319

ret = seteuid(uid);

1320

if(ret == -1){

1321

perror("seteuid");

1322

}

1146

1323

goto end;

1147

1324

}

1148

1325

}

1176

1353

}

1177

1354

}

1178

1355

#endif /* __linux__ */

1179

}

1180

1181

if(quit_now){

1182

goto end;

1183

}

1184

1185

uid = getuid();

1186

gid = getgid();

1187

1188

errno = 0;

1189

setgid(gid);

1190

if(ret == -1){

1191

perror("setgid");

1192

}

1193

1194

ret = setuid(uid);

1195

if(ret == -1){

1196

perror("setuid");

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

}

1197

1371

}

1198

1372

1199

1373

if(quit_now){

1373

1547

1374

1548

/* Take down the network interface */

1375

1549

if(take_down_interface){

1376

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

1550

/* Re-raise priviliges */

1551

errno = 0;

1552

ret = seteuid(0);

1377

1553

if(ret == -1){

1378

perror("ioctl SIOCGIFFLAGS");

1379

} else if(network.ifr_flags & IFF_UP) {

1380

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

1381

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

1382

if(ret == -1){

1383

perror("ioctl SIOCSIFFLAGS");

1384

}

1554

perror("seteuid");

1385

1555

}

1386

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

1387

if(ret == -1){

1388

perror("close");

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

}

1389

1577

}

1390

1578

}

1391

1579

1434

1622

}

1435

1623

1436

1624

if(quit_now){

1437

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

1625

sigemptyset(&old_sigterm_action.sa_mask);

1626

old_sigterm_action.sa_handler = SIG_DFL;

1627

ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,

1628

&old_sigterm_action,

1629

NULL));

1438

1630

if(ret == -1){

1439

1631

perror("sigaction");

1440

1632

}

1441

raise(signal_received);

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());

1442

1641

}

1443

1642

1444

1643

return exitcode;