/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,

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,

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

551

size_t written;

535

int retval = 0;

552

int retval = -1;

536

553

gnutls_session_t session;

537

554

int pf; /* Protocol family */

538

555

565

582

tcp_sd = socket(pf, SOCK_STREAM, 0);

566

583

if(tcp_sd < 0){

567

584

perror("socket");

568

retval = -1;

569

585

goto mandos_end;

570

586

}

571

587

583

599

}

584

600

if(ret < 0 ){

585

601

perror("inet_pton");

586

retval = -1;

587

602

goto mandos_end;

588

603

}

589

604

if(ret == 0){

590

605

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

591

retval = -1;

592

606

goto mandos_end;

593

607

}

594

608

if(af == AF_INET6){

602

616

if(if_index == AVAHI_IF_UNSPEC){

603

617

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

604

618

" without a network interface\n");

605

retval = -1;

606

619

goto mandos_end;

607

620

}

608

621

/* Set the network interface number as scope */

661

674

}

662

675

if(ret < 0){

663

676

perror("connect");

664

retval = -1;

665

677

goto mandos_end;

666

678

}

667

679

677

689

out_size - written));

678

690

if(ret == -1){

679

691

perror("write");

680

retval = -1;

681

692

goto mandos_end;

682

693

}

683

694

written += (size_t)ret;

723

734

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

724

735

gnutls_perror(ret);

725

736

}

726

retval = -1;

727

737

goto mandos_end;

728

738

}

729

739

744

754

buffer_capacity);

745

755

if(buffer_capacity == 0){

746

756

perror("incbuffer");

747

retval = -1;

748

757

goto mandos_end;

749

758

}

750

759

773

782

if(ret < 0){

774

783

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

775

784

gnutls_perror(ret);

776

retval = -1;

777

785

goto mandos_end;

778

786

}

779

787

break;

780

788

default:

781

789

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

782

790

" encrypted session with Mandos server\n");

783

retval = -1;

784

791

gnutls_bye(session, GNUTLS_SHUT_RDWR);

785

792

goto mandos_end;

786

793

}

797

804

goto mandos_end;

798

805

}

799

806

800

gnutls_bye(session, GNUTLS_SHUT_RDWR);

801

802

if(quit_now){

803

goto mandos_end;

804

}

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);

805

813

806

814

if(buffer_length > 0){

807

815

ssize_t decrypted_buffer_size;

824

832

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

825

833

strerror(errno));

826

834

}

827

retval = -1;

828

break;

835

goto mandos_end;

829

836

}

830

837

written += (size_t)ret;

831

838

}

832

free(decrypted_buffer);

833

} else {

834

retval = -1;

839

retval = 0;

835

840

}

836

} else {

837

retval = -1;

838

841

}

839

842

840

843

/* Shutdown procedure */

841

844

842

845

mandos_end:

846

free(decrypted_buffer);

843

847

free(buffer);

844

848

if(tcp_sd >= 0){

845

849

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

995

999

bool gpgme_initialized = false;

996

1000

float delay = 2.5f;

997

1001

998

struct sigaction old_sigterm_action;

1002

struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };

999

1003

struct sigaction sigterm_action = { .sa_handler = handle_sigterm };

1000

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

1001

1026

{

1002

1027

struct argp_option options[] = {

1003

1028

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

1032

1057

.arg = "SECONDS",

1033

1058

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

1034

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 },

1035

1069

{ .name = NULL }

1036

1070

};

1037

1071

1038

1072

error_t parse_opt(int key, char *arg,

1039

1073

struct argp_state *state){

1074

errno = 0;

1040

1075

switch(key){

1041

1076

case 128: /* --debug */

1042

1077

debug = true;

1058

1093

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

1059

1094

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

1060

1095

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

1061

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

1062

exit(EXIT_FAILURE);

1096

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

1063

1097

}

1064

1098

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

1065

1099

break;

1070

1104

errno = 0;

1071

1105

delay = strtof(arg, &tmp);

1072

1106

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

1073

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

1074

exit(EXIT_FAILURE);

1107

argp_error(state, "Bad delay");

1075

1108

}

1076

1109

break;

1077

case ARGP_KEY_ARG:

1078

argp_usage(state);

1079

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);

1080

1123

break;

1081

1124

default:

1082

1125

return ARGP_ERR_UNKNOWN;

1083

1126

}

1084

return 0;

1127

return errno;

1085

1128

}

1086

1129

1087

1130

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

1088

1131

.args_doc = "",

1089

1132

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

1090

1133

" passwords from a Mandos server" };

1091

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

1092

if(ret == ARGP_ERR_UNKNOWN){

1093

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

1094

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;

1095

1147

goto end;

1096

1148

}

1097

1149

}

1187

1239

goto end;

1188

1240

}

1189

1241

1242

/* Re-raise priviliges */

1243

errno = 0;

1244

ret = seteuid(0);

1245

if(ret == -1){

1246

perror("seteuid");

1247

}

1248

1190

1249

#ifdef __linux__

1191

1250

/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO

1192

messages to mess up the prompt */

1251

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

1193

1252

ret = klogctl(8, NULL, 5);

1194

1253

bool restore_loglevel = true;

1195

1254

if(ret == -1){

1210

1269

}

1211

1270

}

1212

1271

#endif /* __linux__ */

1272

/* Lower privileges */

1273

errno = 0;

1274

ret = seteuid(uid);

1275

if(ret == -1){

1276

perror("seteuid");

1277

}

1213

1278

goto end;

1214

1279

}

1215

1280

strcpy(network.ifr_name, interface);

1225

1290

}

1226

1291

#endif /* __linux__ */

1227

1292

exitcode = EXIT_FAILURE;

1293

/* Lower privileges */

1294

errno = 0;

1295

ret = seteuid(uid);

1296

if(ret == -1){

1297

perror("seteuid");

1298

}

1228

1299

goto end;

1229

1300

}

1230

1301

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

1243

1314

}

1244

1315

}

1245

1316

#endif /* __linux__ */

1317

/* Lower privileges */

1318

errno = 0;

1319

ret = seteuid(uid);

1320

if(ret == -1){

1321

perror("seteuid");

1322

}

1246

1323

goto end;

1247

1324

}

1248

1325

}

1276

1353

}

1277

1354

}

1278

1355

#endif /* __linux__ */

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");

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

}

1297

1371

}

1298

1372

1299

1373

if(quit_now){

1473

1547

1474

1548

/* Take down the network interface */

1475

1549

if(take_down_interface){

1476

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

1550

/* Re-raise priviliges */

1551

errno = 0;

1552

ret = seteuid(0);

1477

1553

if(ret == -1){

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

}

1554

perror("seteuid");

1485

1555

}

1486

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

1487

if(ret == -1){

1488

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

}

1489

1577

}

1490

1578

}

1491

1579

1536

1624

if(quit_now){

1537

1625

sigemptyset(&old_sigterm_action.sa_mask);

1538

1626

old_sigterm_action.sa_handler = SIG_DFL;

1539

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

1627

ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,

1628

&old_sigterm_action,

1629

NULL));

1540

1630

if(ret == -1){

1541

1631

perror("sigaction");

1542

1632

}

1543

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());

1544

1641

}

1545

1642

1546

1643

return exitcode;