/mandos/trunk : revision 377

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

142

.dh_bits = 1024, .priority = "SECURE256"

143

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

144

145

sig_atomic_t quit_now = 0;

146

int signal_received = 0;

147

145

148

/*

146

149

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

147

150

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

164

167

*/

165

168

static bool init_gpgme(const char *seckey,

166

169

const char *pubkey, const char *tempdir){

167

int ret;

168

170

gpgme_error_t rc;

169

171

gpgme_engine_info_t engine_info;

170

172

173

175

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

174

176

*/

175

177

bool import_key(const char *filename){

178

int ret;

176

179

int fd;

177

180

gpgme_data_t pgp_data;

178

181

474

477

static int init_gnutls_session(gnutls_session_t *session){

475

478

int ret;

476

479

/* GnuTLS session creation */

477

ret = gnutls_init(session, GNUTLS_SERVER);

480

do {

481

ret = gnutls_init(session, GNUTLS_SERVER);

482

if(quit_now){

483

return -1;

484

}

485

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

478

486

if(ret != GNUTLS_E_SUCCESS){

479

487

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

480

488

safer_gnutls_strerror(ret));

482

490

483

491

{

484

492

const char *err;

485

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

493

do {

494

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

495

if(quit_now){

496

gnutls_deinit(*session);

497

return -1;

498

}

499

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

486

500

if(ret != GNUTLS_E_SUCCESS){

487

501

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

488

502

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

492

506

}

493

507

}

494

508

495

ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,

496

mc.cred);

509

do {

510

ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,

511

mc.cred);

512

if(quit_now){

513

gnutls_deinit(*session);

514

return -1;

515

}

516

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

497

517

if(ret != GNUTLS_E_SUCCESS){

498

518

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

499

519

safer_gnutls_strerror(ret));

502

522

}

503

523

504

524

/* ignore client certificate if any. */

505

gnutls_certificate_server_set_request(*session,

506

GNUTLS_CERT_IGNORE);

525

gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);

507

526

508

527

gnutls_dh_set_prime_bits(*session, mc.dh_bits);

509

528

514

533

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

515

534

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

516

535

517

sig_atomic_t quit_now = 0;

518

int signal_received = 0;

519

520

536

/* Called when a Mandos server is found */

521

537

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

522

538

AvahiIfIndex if_index,

523

539

int af){

524

int ret, tcp_sd;

540

int ret, tcp_sd = -1;

525

541

ssize_t sret;

526

542

union {

527

543

struct sockaddr_in in;

528

544

struct sockaddr_in6 in6;

529

545

} to;

530

546

char *buffer = NULL;

531

char *decrypted_buffer;

547

char *decrypted_buffer = NULL;

532

548

size_t buffer_length = 0;

533

549

size_t buffer_capacity = 0;

534

ssize_t decrypted_buffer_size;

535

550

size_t written;

536

int retval = 0;

551

int retval = -1;

537

552

gnutls_session_t session;

538

553

int pf; /* Protocol family */

539

554

555

if(quit_now){

556

return -1;

557

}

558

540

559

switch(af){

541

560

case AF_INET6:

542

561

pf = PF_INET6;

562

581

tcp_sd = socket(pf, SOCK_STREAM, 0);

563

582

if(tcp_sd < 0){

564

583

perror("socket");

565

return -1;

584

goto mandos_end;

585

}

586

587

if(quit_now){

588

goto mandos_end;

566

589

}

567

590

568

591

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

575

598

}

576

599

if(ret < 0 ){

577

600

perror("inet_pton");

578

return -1;

601

goto mandos_end;

579

602

}

580

603

if(ret == 0){

581

604

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

582

return -1;

605

goto mandos_end;

583

606

}

584

607

if(af == AF_INET6){

585

608

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

592

615

if(if_index == AVAHI_IF_UNSPEC){

593

616

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

594

617

" without a network interface\n");

595

return -1;

618

goto mandos_end;

596

619

}

597

620

/* Set the network interface number as scope */

598

621

to.in6.sin6_scope_id = (uint32_t)if_index;

603

626

-Wunreachable-code */

604

627

}

605

628

629

if(quit_now){

630

goto mandos_end;

631

}

632

606

633

if(debug){

607

634

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

608

635

char interface[IF_NAMESIZE];

635

662

}

636

663

}

637

664

665

if(quit_now){

666

goto mandos_end;

667

}

668

638

669

if(af == AF_INET6){

639

670

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

640

671

} else {

642

673

}

643

674

if(ret < 0){

644

675

perror("connect");

645

return -1;

676

goto mandos_end;

677

}

678

679

if(quit_now){

680

goto mandos_end;

646

681

}

647

682

648

683

const char *out = mandos_protocol_version;

653

688

out_size - written));

654

689

if(ret == -1){

655

690

perror("write");

656

retval = -1;

657

691

goto mandos_end;

658

692

}

659

693

written += (size_t)ret;

667

701

break;

668

702

}

669

703

}

704

705

if(quit_now){

706

goto mandos_end;

707

}

670

708

}

671

709

672

710

if(debug){

673

711

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

674

712

}

675

713

714

if(quit_now){

715

goto mandos_end;

716

}

717

676

718

gnutls_transport_set_ptr(session, (gnutls_transport_ptr_t) tcp_sd);

677

719

678

do{

720

if(quit_now){

721

goto mandos_end;

722

}

723

724

do {

679

725

ret = gnutls_handshake(session);

726

if(quit_now){

727

goto mandos_end;

728

}

680

729

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

681

730

682

731

if(ret != GNUTLS_E_SUCCESS){

684

733

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

685

734

gnutls_perror(ret);

686

735

}

687

retval = -1;

688

736

goto mandos_end;

689

737

}

690

738

696

744

}

697

745

698

746

while(true){

747

748

if(quit_now){

749

goto mandos_end;

750

}

751

699

752

buffer_capacity = incbuffer(&buffer, buffer_length,

700

753

buffer_capacity);

701

754

if(buffer_capacity == 0){

702

755

perror("incbuffer");

703

retval = -1;

756

goto mandos_end;

757

}

758

759

if(quit_now){

704

760

goto mandos_end;

705

761

}

706

762

715

771

case GNUTLS_E_AGAIN:

716

772

break;

717

773

case GNUTLS_E_REHANDSHAKE:

718

do{

774

do {

719

775

ret = gnutls_handshake(session);

776

777

if(quit_now){

778

goto mandos_end;

779

}

720

780

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

721

781

if(ret < 0){

722

782

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

723

783

gnutls_perror(ret);

724

retval = -1;

725

784

goto mandos_end;

726

785

}

727

786

break;

728

787

default:

729

788

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

730

789

" encrypted session with Mandos server\n");

731

retval = -1;

732

790

gnutls_bye(session, GNUTLS_SHUT_RDWR);

733

791

goto mandos_end;

734

792

}

741

799

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

742

800

}

743

801

744

gnutls_bye(session, GNUTLS_SHUT_RDWR);

802

if(quit_now){

803

goto mandos_end;

804

}

805

806

do {

807

ret = gnutls_bye(session, GNUTLS_SHUT_RDWR);

808

if(quit_now){

809

goto mandos_end;

810

}

811

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

745

812

746

813

if(buffer_length > 0){

814

ssize_t decrypted_buffer_size;

747

815

decrypted_buffer_size = pgp_packet_decrypt(buffer,

748

816

buffer_length,

749

817

&decrypted_buffer);

750

818

if(decrypted_buffer_size >= 0){

819

751

820

written = 0;

752

821

while(written < (size_t) decrypted_buffer_size){

822

if(quit_now){

823

goto mandos_end;

824

}

825

753

826

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

754

827

(size_t)decrypted_buffer_size - written,

755

828

stdout);

758

831

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

759

832

strerror(errno));

760

833

}

761

retval = -1;

762

break;

834

goto mandos_end;

763

835

}

764

836

written += (size_t)ret;

765

837

}

766

free(decrypted_buffer);

767

} else {

768

retval = -1;

838

retval = 0;

769

839

}

770

} else {

771

retval = -1;

772

840

}

773

841

774

842

/* Shutdown procedure */

775

843

776

844

mandos_end:

845

free(decrypted_buffer);

777

846

free(buffer);

778

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

847

if(tcp_sd >= 0){

848

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

849

}

779

850

if(ret == -1){

780

851

perror("close");

781

852

}

782

853

gnutls_deinit(session);

854

if(quit_now){

855

retval = -1;

856

}

783

857

return retval;

784

858

}

785

859

848

922

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

849

923

is removed from the LAN */

850

924

925

if(quit_now){

926

return;

927

}

928

851

929

switch(event){

852

930

default:

853

931

case AVAHI_BROWSER_FAILURE:

920

998

bool gpgme_initialized = false;

921

999

float delay = 2.5f;

922

1000

923

struct sigaction old_sigterm_action;

1001

struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };

924

1002

struct sigaction sigterm_action = { .sa_handler = handle_sigterm };

925

1003

1004

uid = getuid();

1005

gid = getgid();

1006

1007

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

1008

errno = 0;

1009

ret = setgid(gid);

1010

if(ret == -1){

1011

perror("setgid");

1012

}

1013

1014

/* Lower user privileges (temporarily) */

1015

errno = 0;

1016

ret = seteuid(uid);

1017

if(ret == -1){

1018

perror("seteuid");

1019

}

1020

1021

if(quit_now){

1022

goto end;

1023

}

1024

926

1025

{

927

1026

struct argp_option options[] = {

928

1027

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

1055

1154

exitcode = EXIT_FAILURE;

1056

1155

goto end;

1057

1156

}

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;

1157

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

1158

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

1159

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

1160

*/

1161

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

1162

if(ret == -1){

1163

perror("sigaction");

1164

return EXIT_FAILURE;

1165

}

1166

if(old_sigterm_action.sa_handler != SIG_IGN){

1167

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

1168

if(ret == -1){

1169

perror("sigaction");

1170

exitcode = EXIT_FAILURE;

1171

goto end;

1172

}

1173

}

1174

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

1175

if(ret == -1){

1176

perror("sigaction");

1177

return EXIT_FAILURE;

1178

}

1179

if(old_sigterm_action.sa_handler != SIG_IGN){

1180

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

1181

if(ret == -1){

1182

perror("sigaction");

1183

exitcode = EXIT_FAILURE;

1184

goto end;

1185

}

1186

}

1187

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

1188

if(ret == -1){

1189

perror("sigaction");

1190

return EXIT_FAILURE;

1191

}

1192

if(old_sigterm_action.sa_handler != SIG_IGN){

1193

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

1194

if(ret == -1){

1195

perror("sigaction");

1196

exitcode = EXIT_FAILURE;

1197

goto end;

1198

}

1075

1199

}

1076

1200

1077

1201

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

1087

1211

goto end;

1088

1212

}

1089

1213

1214

/* Re-raise priviliges */

1215

errno = 0;

1216

ret = seteuid(0);

1217

if(ret == -1){

1218

perror("seteuid");

1219

}

1220

1090

1221

#ifdef __linux__

1091

1222

/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO

1092

1223

messages to mess up the prompt */

1110

1241

}

1111

1242

}

1112

1243

#endif /* __linux__ */

1244

/* Lower privileges */

1245

errno = 0;

1246

ret = seteuid(uid);

1247

if(ret == -1){

1248

perror("seteuid");

1249

}

1113

1250

goto end;

1114

1251

}

1115

1252

strcpy(network.ifr_name, interface);

1125

1262

}

1126

1263

#endif /* __linux__ */

1127

1264

exitcode = EXIT_FAILURE;

1265

/* Lower privileges */

1266

errno = 0;

1267

ret = seteuid(uid);

1268

if(ret == -1){

1269

perror("seteuid");

1270

}

1128

1271

goto end;

1129

1272

}

1130

1273

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

1143

1286

}

1144

1287

}

1145

1288

#endif /* __linux__ */

1289

/* Lower privileges */

1290

errno = 0;

1291

ret = seteuid(uid);

1292

if(ret == -1){

1293

perror("seteuid");

1294

}

1146

1295

goto end;

1147

1296

}

1148

1297

}

1176

1325

}

1177

1326

}

1178

1327

#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");

1328

/* Lower privileges */

1329

errno = 0;

1330

if(take_down_interface){

1331

/* Lower privileges */

1332

ret = seteuid(uid);

1333

if(ret == -1){

1334

perror("seteuid");

1335

}

1336

} else {

1337

/* Lower privileges permanently */

1338

ret = setuid(uid);

1339

if(ret == -1){

1340

perror("setuid");

1341

}

1342

}

1197

1343

}

1198

1344

1199

1345

if(quit_now){

1373

1519

1374

1520

/* Take down the network interface */

1375

1521

if(take_down_interface){

1376

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

1522

/* Re-raise priviliges */

1523

errno = 0;

1524

ret = seteuid(0);

1377

1525

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

}

1526

perror("seteuid");

1385

1527

}

1386

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

1387

if(ret == -1){

1388

perror("close");

1528

if(geteuid() == 0){

1529

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

1530

if(ret == -1){

1531

perror("ioctl SIOCGIFFLAGS");

1532

} else if(network.ifr_flags & IFF_UP) {

1533

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

1534

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

1535

if(ret == -1){

1536

perror("ioctl SIOCSIFFLAGS");

1537

}

1538

}

1539

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

1540

if(ret == -1){

1541

perror("close");

1542

}

1543

/* Lower privileges permanently */

1544

errno = 0;

1545

ret = setuid(uid);

1546

if(ret == -1){

1547

perror("setuid");

1548

}

1389

1549

}

1390

1550

}

1391

1551

1434

1594

}

1435

1595

1436

1596

if(quit_now){

1437

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

1597

sigemptyset(&old_sigterm_action.sa_mask);

1598

old_sigterm_action.sa_handler = SIG_DFL;

1599

ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,

1600

&old_sigterm_action,

1601

NULL));

1438

1602

if(ret == -1){

1439

1603

perror("sigaction");

1440

1604

}

1441

raise(signal_received);

1605

do {

1606

ret = raise(signal_received);

1607

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

1608

if(ret != 0){

1609

perror("raise");

1610

abort();

1611

}

1612

TEMP_FAILURE_RETRY(pause());

1442

1613

}

1443

1614

1444

1615

return exitcode;