/mandos/trunk : revision 694

9

* "browse_callback", and parts of "main".

10

*

11

* Everything else is

12

13

12

13

14

*

15

* This program is free software: you can redistribute it and/or

16

* modify it under the terms of the GNU General Public License as

46

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

47

strtof(), abort() */

48

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

49

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

50

asprintf(), strncpy() */

49

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

50

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

51

#include <sys/ioctl.h> /* ioctl */

52

#include <sys/types.h> /* socket(), inet_pton(), sockaddr,

53

sockaddr_in6, PF_INET6,

234

.af = af };

235

if(new_server->ip == NULL){

236

perror_plus("strdup");

237

free(new_server);

238

237

return false;

239

238

}

240

239

ret = clock_gettime(CLOCK_MONOTONIC, &(new_server->last_seen));

241

240

if(ret == -1){

242

241

perror_plus("clock_gettime");

243

#ifdef __GNUC__

244

#pragma GCC diagnostic push

245

#pragma GCC diagnostic ignored "-Wcast-qual"

246

#endif

247

free((char *)(new_server->ip));

248

#ifdef __GNUC__

249

#pragma GCC diagnostic pop

250

#endif

251

free(new_server);

252

242

return false;

253

243

}

254

244

/* Special case of first server */

305

295

return false;

306

296

}

307

297

308

ret = close(fd);

298

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

309

299

if(ret == -1){

310

300

perror_plus("close");

311

301

}

493

483

return plaintext_length;

494

484

}

495

485

496

__attribute__((warn_unused_result, const))

497

static const char *safe_string(const char *str){

498

if(str == NULL)

499

return "(unknown)";

500

return str;

501

}

502

503

486

__attribute__((warn_unused_result))

504

487

static const char *safer_gnutls_strerror(int value){

505

488

const char *ret = gnutls_strerror(value);

506

return safe_string(ret);

489

if(ret == NULL)

490

ret = "(unknown)";

491

return ret;

507

492

}

508

493

509

494

/* GnuTLS log function callback */

516

501

__attribute__((nonnull, warn_unused_result))

517

502

static int init_gnutls_global(const char *pubkeyfilename,

518

503

const char *seckeyfilename,

519

const char *dhparamsfilename,

520

504

mandos_context *mc){

521

505

int ret;

522

unsigned int uret;

523

506

524

507

if(debug){

525

508

fprintf_plus(stderr, "Initializing GnuTLS\n");

576

559

safer_gnutls_strerror(ret));

577

560

goto globalfail;

578

561

}

579

/* If a Diffie-Hellman parameters file was given, try to use it */

580

if(dhparamsfilename != NULL){

581

gnutls_datum_t params = { .data = NULL, .size = 0 };

582

do {

583

int dhpfile = open(dhparamsfilename, O_RDONLY);

584

if(dhpfile == -1){

585

perror_plus("open");

586

dhparamsfilename = NULL;

587

break;

588

}

589

size_t params_capacity = 0;

590

while(true){

591

params_capacity = incbuffer((char **)&params.data,

592

(size_t)params.size,

593

(size_t)params_capacity);

594

if(params_capacity == 0){

595

perror_plus("incbuffer");

596

free(params.data);

597

params.data = NULL;

598

dhparamsfilename = NULL;

599

break;

600

}

601

ssize_t bytes_read = read(dhpfile,

602

params.data + params.size,

603

BUFFER_SIZE);

604

/* EOF */

605

if(bytes_read == 0){

606

break;

607

}

608

/* check bytes_read for failure */

609

if(bytes_read < 0){

610

perror_plus("read");

611

free(params.data);

612

params.data = NULL;

613

dhparamsfilename = NULL;

614

break;

615

}

616

params.size += (unsigned int)bytes_read;

617

}

618

if(params.data == NULL){

619

dhparamsfilename = NULL;

620

}

621

if(dhparamsfilename == NULL){

622

break;

623

}

624

ret = gnutls_dh_params_import_pkcs3(mc->dh_params, &params,

625

GNUTLS_X509_FMT_PEM);

626

if(ret != GNUTLS_E_SUCCESS){

627

fprintf_plus(stderr, "Failed to parse DH parameters in file"

628

" \"%s\": %s\n", dhparamsfilename,

629

safer_gnutls_strerror(ret));

630

dhparamsfilename = NULL;

631

}

632

} while(false);

633

}

634

if(dhparamsfilename == NULL){

635

if(mc->dh_bits == 0){

636

/* Find out the optimal number of DH bits */

637

/* Try to read the private key file */

638

gnutls_datum_t buffer = { .data = NULL, .size = 0 };

639

do {

640

int secfile = open(seckeyfilename, O_RDONLY);

641

if(secfile == -1){

642

perror_plus("open");

643

break;

644

}

645

size_t buffer_capacity = 0;

646

while(true){

647

buffer_capacity = incbuffer((char **)&buffer.data,

648

(size_t)buffer.size,

649

(size_t)buffer_capacity);

650

if(buffer_capacity == 0){

651

perror_plus("incbuffer");

652

free(buffer.data);

653

buffer.data = NULL;

654

break;

655

}

656

ssize_t bytes_read = read(secfile,

657

buffer.data + buffer.size,

658

BUFFER_SIZE);

659

/* EOF */

660

if(bytes_read == 0){

661

break;

662

}

663

/* check bytes_read for failure */

664

if(bytes_read < 0){

665

perror_plus("read");

666

free(buffer.data);

667

buffer.data = NULL;

668

break;

669

}

670

buffer.size += (unsigned int)bytes_read;

671

}

672

close(secfile);

673

} while(false);

674

/* If successful, use buffer to parse private key */

675

gnutls_sec_param_t sec_param = GNUTLS_SEC_PARAM_ULTRA;

676

if(buffer.data != NULL){

677

{

678

gnutls_openpgp_privkey_t privkey = NULL;

679

ret = gnutls_openpgp_privkey_init(&privkey);

680

if(ret != GNUTLS_E_SUCCESS){

681

fprintf_plus(stderr, "Error initializing OpenPGP key"

682

" structure: %s",

683

safer_gnutls_strerror(ret));

684

free(buffer.data);

685

buffer.data = NULL;

686

} else {

687

ret = gnutls_openpgp_privkey_import

688

(privkey, &buffer, GNUTLS_OPENPGP_FMT_BASE64, "", 0);

689

if(ret != GNUTLS_E_SUCCESS){

690

fprintf_plus(stderr, "Error importing OpenPGP key : %s",

691

safer_gnutls_strerror(ret));

692

privkey = NULL;

693

}

694

free(buffer.data);

695

buffer.data = NULL;

696

if(privkey != NULL){

697

/* Use private key to suggest an appropriate

698

sec_param */

699

sec_param = gnutls_openpgp_privkey_sec_param(privkey);

700

gnutls_openpgp_privkey_deinit(privkey);

701

if(debug){

702

fprintf_plus(stderr, "This OpenPGP key implies using"

703

" a GnuTLS security parameter \"%s\".\n",

704

safe_string(gnutls_sec_param_get_name

705

(sec_param)));

706

}

707

}

708

}

709

}

710

if(sec_param == GNUTLS_SEC_PARAM_UNKNOWN){

711

/* Err on the side of caution */

712

sec_param = GNUTLS_SEC_PARAM_ULTRA;

713

if(debug){

714

fprintf_plus(stderr, "Falling back to security parameter"

715

" \"%s\"\n",

716

safe_string(gnutls_sec_param_get_name

717

(sec_param)));

718

}

719

}

720

}

721

uret = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, sec_param);

722

if(uret != 0){

723

mc->dh_bits = uret;

724

if(debug){

725

fprintf_plus(stderr, "A \"%s\" GnuTLS security parameter"

726

" implies %u DH bits; using that.\n",

727

safe_string(gnutls_sec_param_get_name

728

(sec_param)),

729

mc->dh_bits);

730

}

731

} else {

732

fprintf_plus(stderr, "Failed to get implied number of DH"

733

" bits for security parameter \"%s\"): %s\n",

734

safe_string(gnutls_sec_param_get_name

735

(sec_param)),

736

safer_gnutls_strerror(ret));

737

goto globalfail;

738

}

739

} else if(debug){

740

fprintf_plus(stderr, "DH bits explicitly set to %u\n",

741

mc->dh_bits);

742

}

743

ret = gnutls_dh_params_generate2(mc->dh_params, mc->dh_bits);

744

if(ret != GNUTLS_E_SUCCESS){

745

fprintf_plus(stderr, "Error in GnuTLS prime generation (%u"

746

" bits): %s\n", mc->dh_bits,

747

safer_gnutls_strerror(ret));

748

goto globalfail;

749

}

750

}

562

ret = gnutls_dh_params_generate2(mc->dh_params, mc->dh_bits);

563

if(ret != GNUTLS_E_SUCCESS){

564

fprintf_plus(stderr, "Error in GnuTLS prime generation: %s\n",

565

safer_gnutls_strerror(ret));

566

goto globalfail;

567

}

568

751

569

gnutls_certificate_set_dh_params(mc->cred, mc->dh_params);

752

570

753

571

return 0;

813

631

/* ignore client certificate if any. */

814

632

gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);

815

633

634

gnutls_dh_set_prime_bits(*session, mc->dh_bits);

635

816

636

return 0;

817

637

}

818

638

820

640

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

821

641

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

822

642

823

/* Set effective uid to 0, return errno */

824

__attribute__((warn_unused_result))

825

error_t raise_privileges(void){

826

error_t old_errno = errno;

827

error_t ret_errno = 0;

828

if(seteuid(0) == -1){

829

ret_errno = errno;

830

}

831

errno = old_errno;

832

return ret_errno;

833

}

834

835

/* Set effective and real user ID to 0. Return errno. */

836

__attribute__((warn_unused_result))

837

error_t raise_privileges_permanently(void){

838

error_t old_errno = errno;

839

error_t ret_errno = raise_privileges();

840

if(ret_errno != 0){

841

errno = old_errno;

842

return ret_errno;

843

}

844

if(setuid(0) == -1){

845

ret_errno = errno;

846

}

847

errno = old_errno;

848

return ret_errno;

849

}

850

851

/* Set effective user ID to unprivileged saved user ID */

852

__attribute__((warn_unused_result))

853

error_t lower_privileges(void){

854

error_t old_errno = errno;

855

error_t ret_errno = 0;

856

if(seteuid(uid) == -1){

857

ret_errno = errno;

858

}

859

errno = old_errno;

860

return ret_errno;

861

}

862

863

/* Lower privileges permanently */

864

__attribute__((warn_unused_result))

865

error_t lower_privileges_permanently(void){

866

error_t old_errno = errno;

867

error_t ret_errno = 0;

868

if(setuid(uid) == -1){

869

ret_errno = errno;

870

}

871

errno = old_errno;

872

return ret_errno;

873

}

874

875

/* Helper function to add_local_route() and delete_local_route() */

876

__attribute__((nonnull, warn_unused_result))

877

static bool add_delete_local_route(const bool add,

878

const char *address,

879

AvahiIfIndex if_index){

880

int ret;

881

char helper[] = "mandos-client-iprouteadddel";

882

char add_arg[] = "add";

883

char delete_arg[] = "delete";

884

char debug_flag[] = "--debug";

885

char *pluginhelperdir = getenv("MANDOSPLUGINHELPERDIR");

886

if(pluginhelperdir == NULL){

887

if(debug){

888

fprintf_plus(stderr, "MANDOSPLUGINHELPERDIR environment"

889

" variable not set; cannot run helper\n");

890

}

891

return false;

892

}

893

894

char interface[IF_NAMESIZE];

895

if(if_indextoname((unsigned int)if_index, interface) == NULL){

896

perror_plus("if_indextoname");

897

return false;

898

}

899

900

int devnull = (int)TEMP_FAILURE_RETRY(open("/dev/null", O_RDONLY));

901

if(devnull == -1){

902

perror_plus("open(\"/dev/null\", O_RDONLY)");

903

return false;

904

}

905

pid_t pid = fork();

906

if(pid == 0){

907

/* Child */

908

/* Raise privileges */

909

errno = raise_privileges_permanently();

910

if(errno != 0){

911

perror_plus("Failed to raise privileges");

912

/* _exit(EX_NOPERM); */

913

} else {

914

/* Set group */

915

errno = 0;

916

ret = setgid(0);

917

if(ret == -1){

918

perror_plus("setgid");

919

_exit(EX_NOPERM);

920

}

921

/* Reset supplementary groups */

922

errno = 0;

923

ret = setgroups(0, NULL);

924

if(ret == -1){

925

perror_plus("setgroups");

926

_exit(EX_NOPERM);

927

}

928

}

929

ret = dup2(devnull, STDIN_FILENO);

930

if(ret == -1){

931

perror_plus("dup2(devnull, STDIN_FILENO)");

932

_exit(EX_OSERR);

933

}

934

ret = close(devnull);

935

if(ret == -1){

936

perror_plus("close");

937

_exit(EX_OSERR);

938

}

939

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

940

if(ret == -1){

941

perror_plus("dup2(STDERR_FILENO, STDOUT_FILENO)");

942

_exit(EX_OSERR);

943

}

944

int helperdir_fd = (int)TEMP_FAILURE_RETRY(open(pluginhelperdir,

945

O_RDONLY

946

| O_DIRECTORY

947

| O_PATH

948

| O_CLOEXEC));

949

if(helperdir_fd == -1){

950

perror_plus("open");

951

_exit(EX_UNAVAILABLE);

952

}

953

int helper_fd = (int)TEMP_FAILURE_RETRY(openat(helperdir_fd,

954

helper, O_RDONLY));

955

if(helper_fd == -1){

956

perror_plus("openat");

957

close(helperdir_fd);

958

_exit(EX_UNAVAILABLE);

959

}

960

close(helperdir_fd);

961

#ifdef __GNUC__

962

#pragma GCC diagnostic push

963

#pragma GCC diagnostic ignored "-Wcast-qual"

964

#endif

965

if(fexecve(helper_fd, (char *const [])

966

{ helper, add ? add_arg : delete_arg, (char *)address,

967

interface, debug ? debug_flag : NULL, NULL },

968

environ) == -1){

969

#ifdef __GNUC__

970

#pragma GCC diagnostic pop

971

#endif

972

perror_plus("fexecve");

973

_exit(EXIT_FAILURE);

974

}

975

}

976

if(pid == -1){

977

perror_plus("fork");

978

return false;

979

}

980

int status;

981

pid_t pret = -1;

982

errno = 0;

983

do {

984

pret = waitpid(pid, &status, 0);

985

if(pret == -1 and errno == EINTR and quit_now){

986

int errno_raising = 0;

987

if((errno = raise_privileges()) != 0){

988

errno_raising = errno;

989

perror_plus("Failed to raise privileges in order to"

990

" kill helper program");

991

}

992

if(kill(pid, SIGTERM) == -1){

993

perror_plus("kill");

994

}

995

if((errno_raising == 0) and (errno = lower_privileges()) != 0){

996

perror_plus("Failed to lower privileges after killing"

997

" helper program");

998

}

999

return false;

1000

}

1001

} while(pret == -1 and errno == EINTR);

1002

if(pret == -1){

1003

perror_plus("waitpid");

1004

return false;

1005

}

1006

if(WIFEXITED(status)){

1007

if(WEXITSTATUS(status) != 0){

1008

fprintf_plus(stderr, "Error: iprouteadddel exited"

1009

" with status %d\n", WEXITSTATUS(status));

1010

return false;

1011

}

1012

return true;

1013

}

1014

if(WIFSIGNALED(status)){

1015

fprintf_plus(stderr, "Error: iprouteadddel died by"

1016

" signal %d\n", WTERMSIG(status));

1017

return false;

1018

}

1019

fprintf_plus(stderr, "Error: iprouteadddel crashed\n");

1020

return false;

1021

}

1022

1023

__attribute__((nonnull, warn_unused_result))

1024

static bool add_local_route(const char *address,

1025

AvahiIfIndex if_index){

1026

if(debug){

1027

fprintf_plus(stderr, "Adding route to %s\n", address);

1028

}

1029

return add_delete_local_route(true, address, if_index);

1030

}

1031

1032

__attribute__((nonnull, warn_unused_result))

1033

static bool delete_local_route(const char *address,

1034

AvahiIfIndex if_index){

1035

if(debug){

1036

fprintf_plus(stderr, "Removing route to %s\n", address);

1037

}

1038

return add_delete_local_route(false, address, if_index);

1039

}

1040

1041

643

/* Called when a Mandos server is found */

1042

644

__attribute__((nonnull, warn_unused_result))

1043

645

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

1054

656

int retval = -1;

1055

657

gnutls_session_t session;

1056

658

int pf; /* Protocol family */

1057

bool route_added = false;

1058

659

1059

660

errno = 0;

1060

661

1118

719

PRIuMAX "\n", ip, (uintmax_t)port);

1119

720

}

1120

721

1121

tcp_sd = socket(pf, SOCK_STREAM | SOCK_CLOEXEC, 0);

722

tcp_sd = socket(pf, SOCK_STREAM, 0);

1122

723

if(tcp_sd < 0){

1123

724

int e = errno;

1124

725

perror_plus("socket");

1131

732

goto mandos_end;

1132

733

}

1133

734

735

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

1134

736

if(af == AF_INET6){

1135

struct sockaddr_in6 *to6 = (struct sockaddr_in6 *)&to;

1136

*to6 = (struct sockaddr_in6){ .sin6_family = (sa_family_t)af };

1137

ret = inet_pton(af, ip, &to6->sin6_addr);

737

((struct sockaddr_in6 *)&to)->sin6_family = (sa_family_t)af;

738

ret = inet_pton(af, ip, &((struct sockaddr_in6 *)&to)->sin6_addr);

1138

739

} else { /* IPv4 */

1139

struct sockaddr_in *to4 = (struct sockaddr_in *)&to;

1140

*to4 = (struct sockaddr_in){ .sin_family = (sa_family_t)af };

1141

ret = inet_pton(af, ip, &to4->sin_addr);

740

((struct sockaddr_in *)&to)->sin_family = (sa_family_t)af;

741

ret = inet_pton(af, ip, &((struct sockaddr_in *)&to)->sin_addr);

1142

742

}

1143

743

if(ret < 0 ){

1144

744

int e = errno;

1214

814

goto mandos_end;

1215

815

}

1216

816

1217

while(true){

1218

if(af == AF_INET6){

1219

ret = connect(tcp_sd, (struct sockaddr *)&to,

1220

sizeof(struct sockaddr_in6));

1221

} else {

1222

ret = connect(tcp_sd, (struct sockaddr *)&to, /* IPv4 */

1223

sizeof(struct sockaddr_in));

1224

}

1225

if(ret < 0){

1226

if(((errno == ENETUNREACH) or (errno == EHOSTUNREACH))

1227

and if_index != AVAHI_IF_UNSPEC

1228

and connect_to == NULL

1229

and not route_added and

1230

((af == AF_INET6 and not

1231

IN6_IS_ADDR_LINKLOCAL(&(((struct sockaddr_in6 *)

1232

&to)->sin6_addr)))

1233

or (af == AF_INET and

1234

/* Not a a IPv4LL address */

1235

(ntohl(((struct sockaddr_in *)&to)->sin_addr.s_addr)

1236

& 0xFFFF0000L) != 0xA9FE0000L))){

1237

/* Work around Avahi bug - Avahi does not announce link-local

1238

addresses if it has a global address, so local hosts with

1239

*only* a link-local address (e.g. Mandos clients) cannot

1240

connect to a Mandos server announced by Avahi on a server

1241

host with a global address. Work around this by retrying

1242

with an explicit route added with the server's address.

1243

1244

Avahi bug reference:

1245

http://lists.freedesktop.org/archives/avahi/2010-February/001833.html

1246

https://bugs.debian.org/587961

1247

*/

1248

if(debug){

1249

fprintf_plus(stderr, "Mandos server unreachable, trying"

1250

" direct route\n");

1251

}

1252

int e = errno;

1253

route_added = add_local_route(ip, if_index);

1254

if(route_added){

1255

continue;

1256

}

1257

errno = e;

1258

}

1259

if(errno != ECONNREFUSED or debug){

1260

int e = errno;

1261

perror_plus("connect");

1262

errno = e;

1263

}

1264

goto mandos_end;

1265

}

1266

1267

if(quit_now){

1268

errno = EINTR;

1269

goto mandos_end;

1270

}

1271

break;

817

if(af == AF_INET6){

818

ret = connect(tcp_sd, (struct sockaddr *)&to,

819

sizeof(struct sockaddr_in6));

820

} else {

821

ret = connect(tcp_sd, (struct sockaddr *)&to, /* IPv4 */

822

sizeof(struct sockaddr_in));

823

}

824

if(ret < 0){

825

if((errno != ECONNREFUSED and errno != ENETUNREACH) or debug){

826

int e = errno;

827

perror_plus("connect");

828

errno = e;

829

}

830

goto mandos_end;

831

}

832

833

if(quit_now){

834

errno = EINTR;

835

goto mandos_end;

1272

836

}

1273

837

1274

838

const char *out = mandos_protocol_version;

1457

1021

1458

1022

mandos_end:

1459

1023

{

1460

if(route_added){

1461

if(not delete_local_route(ip, if_index)){

1462

fprintf_plus(stderr, "Failed to delete local route to %s on"

1463

" interface %d", ip, if_index);

1464

}

1465

}

1466

1024

int e = errno;

1467

1025

free(decrypted_buffer);

1468

1026

free(buffer);

1469

1027

if(tcp_sd >= 0){

1470

ret = close(tcp_sd);

1028

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

1471

1029

}

1472

1030

if(ret == -1){

1473

1031

if(e == 0){

1508

1066

timed out */

1509

1067

1510

1068

if(quit_now){

1511

avahi_s_service_resolver_free(r);

1512

1069

return;

1513

1070

}

1514

1071

1637

1194

errno = ret_errno;

1638

1195

return false;

1639

1196

}

1640

strncpy(ifr->ifr_name, ifname, IF_NAMESIZE);

1641

ifr->ifr_name[IF_NAMESIZE-1] = '\0'; /* NUL terminate */

1197

strcpy(ifr->ifr_name, ifname);

1642

1198

ret = ioctl(s, SIOCGIFFLAGS, ifr);

1643

1199

if(ret == -1){

1644

1200

if(debug){

1895

1451

}

1896

1452

}

1897

1453

1454

/* Set effective uid to 0, return errno */

1455

__attribute__((warn_unused_result))

1456

error_t raise_privileges(void){

1457

error_t old_errno = errno;

1458

error_t ret_errno = 0;

1459

if(seteuid(0) == -1){

1460

ret_errno = errno;

1461

perror_plus("seteuid");

1462

}

1463

errno = old_errno;

1464

return ret_errno;

1465

}

1466

1467

/* Set effective and real user ID to 0. Return errno. */

1468

__attribute__((warn_unused_result))

1469

error_t raise_privileges_permanently(void){

1470

error_t old_errno = errno;

1471

error_t ret_errno = raise_privileges();

1472

if(ret_errno != 0){

1473

errno = old_errno;

1474

return ret_errno;

1475

}

1476

if(setuid(0) == -1){

1477

ret_errno = errno;

1478

perror_plus("seteuid");

1479

}

1480

errno = old_errno;

1481

return ret_errno;

1482

}

1483

1484

/* Set effective user ID to unprivileged saved user ID */

1485

__attribute__((warn_unused_result))

1486

error_t lower_privileges(void){

1487

error_t old_errno = errno;

1488

error_t ret_errno = 0;

1489

if(seteuid(uid) == -1){

1490

ret_errno = errno;

1491

perror_plus("seteuid");

1492

}

1493

errno = old_errno;

1494

return ret_errno;

1495

}

1496

1497

/* Lower privileges permanently */

1498

__attribute__((warn_unused_result))

1499

error_t lower_privileges_permanently(void){

1500

error_t old_errno = errno;

1501

error_t ret_errno = 0;

1502

if(setuid(uid) == -1){

1503

ret_errno = errno;

1504

perror_plus("setuid");

1505

}

1506

errno = old_errno;

1507

return ret_errno;

1508

}

1509

1510

#ifndef O_CLOEXEC

1511

/*

1512

* Based on the example in the GNU LibC manual chapter 13.13 "File

1513

* Descriptor Flags".

1514

| [[info:libc:Descriptor%20Flags][File Descriptor Flags]] |

1515

*/

1516

__attribute__((warn_unused_result))

1517

static int set_cloexec_flag(int fd){

1518

int ret = (int)TEMP_FAILURE_RETRY(fcntl(fd, F_GETFD, 0));

1519

/* If reading the flags failed, return error indication now. */

1520

if(ret < 0){

1521

return ret;

1522

}

1523

/* Store modified flag word in the descriptor. */

1524

return (int)TEMP_FAILURE_RETRY(fcntl(fd, F_SETFD,

1525

ret | FD_CLOEXEC));

1526

}

1527

#endif /* not O_CLOEXEC */

1528

1898

1529

__attribute__((nonnull))

1899

1530

void run_network_hooks(const char *mode, const char *interface,

1900

1531

const float delay){

1901

struct dirent **direntries = NULL;

1532

struct dirent **direntries;

1902

1533

if(hookdir_fd == -1){

1903

hookdir_fd = open(hookdir, O_RDONLY | O_DIRECTORY | O_PATH

1904

| O_CLOEXEC);

1534

hookdir_fd = open(hookdir, O_RDONLY |

1535

#ifdef O_CLOEXEC

1536

O_CLOEXEC

1537

#else /* not O_CLOEXEC */

1538

0

1539

#endif /* not O_CLOEXEC */

1540

);

1905

1541

if(hookdir_fd == -1){

1906

1542

if(errno == ENOENT){

1907

1543

if(debug){

1913

1549

}

1914

1550

return;

1915

1551

}

1552

#ifndef O_CLOEXEC

1553

if(set_cloexec_flag(hookdir_fd) < 0){

1554

perror_plus("set_cloexec_flag");

1555

if((int)TEMP_FAILURE_RETRY(close(hookdir_fd)) == -1){

1556

perror_plus("close");

1557

} else {

1558

hookdir_fd = -1;

1559

}

1560

return;

1561

}

1562

#endif /* not O_CLOEXEC */

1916

1563

}

1917

1564

#ifdef __GLIBC__

1918

1565

#if __GLIBC_PREREQ(2, 15)

1932

1579

}

1933

1580

struct dirent *direntry;

1934

1581

int ret;

1935

int devnull = (int)TEMP_FAILURE_RETRY(open("/dev/null", O_RDONLY));

1936

if(devnull == -1){

1937

perror_plus("open(\"/dev/null\", O_RDONLY)");

1938

return;

1939

}

1582

int devnull = open("/dev/null", O_RDONLY);

1940

1583

for(int i = 0; i < numhooks; i++){

1941

1584

direntry = direntries[i];

1942

1585

if(debug){

1947

1590

if(hook_pid == 0){

1948

1591

/* Child */

1949

1592

/* Raise privileges */

1950

errno = raise_privileges_permanently();

1951

if(errno != 0){

1593

if(raise_privileges_permanently() != 0){

1952

1594

perror_plus("Failed to raise privileges");

1953

1595

_exit(EX_NOPERM);

1954

1596

}

1966

1608

perror_plus("setgroups");

1967

1609

_exit(EX_NOPERM);

1968

1610

}

1611

ret = dup2(devnull, STDIN_FILENO);

1612

if(ret == -1){

1613

perror_plus("dup2(devnull, STDIN_FILENO)");

1614

_exit(EX_OSERR);

1615

}

1616

ret = close(devnull);

1617

if(ret == -1){

1618

perror_plus("close");

1619

_exit(EX_OSERR);

1620

}

1621

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

1622

if(ret == -1){

1623

perror_plus("dup2(STDERR_FILENO, STDOUT_FILENO)");

1624

_exit(EX_OSERR);

1625

}

1969

1626

ret = setenv("MANDOSNETHOOKDIR", hookdir, 1);

1970

1627

if(ret == -1){

1971

1628

perror_plus("setenv");

2006

1663

_exit(EX_OSERR);

2007

1664

}

2008

1665

}

2009

int hook_fd = (int)TEMP_FAILURE_RETRY(openat(hookdir_fd,

2010

direntry->d_name,

2011

O_RDONLY));

2012

if(hook_fd == -1){

2013

perror_plus("openat");

2014

_exit(EXIT_FAILURE);

2015

}

2016

if(close(hookdir_fd) == -1){

2017

perror_plus("close");

2018

_exit(EXIT_FAILURE);

2019

}

2020

ret = dup2(devnull, STDIN_FILENO);

2021

if(ret == -1){

2022

perror_plus("dup2(devnull, STDIN_FILENO)");

2023

_exit(EX_OSERR);

2024

}

2025

ret = close(devnull);

2026

if(ret == -1){

2027

perror_plus("close");

2028

_exit(EX_OSERR);

2029

}

2030

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

2031

if(ret == -1){

2032

perror_plus("dup2(STDERR_FILENO, STDOUT_FILENO)");

2033

_exit(EX_OSERR);

2034

}

2035

if(fexecve(hook_fd, (char *const []){ direntry->d_name, NULL },

2036

environ) == -1){

1666

if(fexecve(hookdir_fd, (char *const [])

1667

{ direntry->d_name, NULL }, environ) == -1){

2037

1668

perror_plus("fexecve");

2038

1669

_exit(EXIT_FAILURE);

2039

1670

}

2040

1671

} else {

2041

if(hook_pid == -1){

2042

perror_plus("fork");

2043

free(direntry);

2044

continue;

2045

}

2046

1672

int status;

2047

1673

if(TEMP_FAILURE_RETRY(waitpid(hook_pid, &status, 0)) == -1){

2048

1674

perror_plus("waitpid");

2049

free(direntry);

2050

1675

continue;

2051

1676

}

2052

1677

if(WIFEXITED(status)){

2054

1679

fprintf_plus(stderr, "Warning: network hook \"%s\" exited"

2055

1680

" with status %d\n", direntry->d_name,

2056

1681

WEXITSTATUS(status));

2057

free(direntry);

2058

1682

continue;

2059

1683

}

2060

1684

} else if(WIFSIGNALED(status)){

2061

1685

fprintf_plus(stderr, "Warning: network hook \"%s\" died by"

2062

1686

" signal %d\n", direntry->d_name,

2063

1687

WTERMSIG(status));

2064

free(direntry);

2065

1688

continue;

2066

1689

} else {

2067

1690

fprintf_plus(stderr, "Warning: network hook \"%s\""

2068

1691

" crashed\n", direntry->d_name);

2069

free(direntry);

2070

1692

continue;

2071

1693

}

2072

1694

}

2074

1696

fprintf_plus(stderr, "Network hook \"%s\" ran successfully\n",

2075

1697

direntry->d_name);

2076

1698

}

2077

free(direntry);

2078

1699

}

2079

free(direntries);

2080

if(close(hookdir_fd) == -1){

1700

if((int)TEMP_FAILURE_RETRY(close(hookdir_fd)) == -1){

2081

1701

perror_plus("close");

2082

1702

} else {

2083

1703

hookdir_fd = -1;

2123

1743

}

2124

1744

2125

1745

if(quit_now){

2126

ret = close(sd);

1746

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

2127

1747

if(ret == -1){

2128

1748

perror_plus("close");

2129

1749

}

2139

1759

/* Raise privileges */

2140

1760

ret_errno = raise_privileges();

2141

1761

if(ret_errno != 0){

2142

errno = ret_errno;

2143

1762

perror_plus("Failed to raise privileges");

2144

1763

}

2145

1764

2179

1798

}

2180

1799

2181

1800

/* Close the socket */

2182

ret = close(sd);

1801

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

2183

1802

if(ret == -1){

2184

1803

perror_plus("close");

2185

1804

}

2249

1868

/* Raise privileges */

2250

1869

ret_errno = raise_privileges();

2251

1870

if(ret_errno != 0){

2252

errno = ret_errno;

2253

1871

perror_plus("Failed to raise privileges");

2254

1872

}

2255

1873

2267

1885

}

2268

1886

2269

1887

/* Close the socket */

2270

int ret = close(sd);

1888

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

2271

1889

if(ret == -1){

2272

1890

perror_plus("close");

2273

1891

}

2288

1906

}

2289

1907

2290

1908

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

2291

mandos_context mc = { .server = NULL, .dh_bits = 0,

2292

.priority = "SECURE256:!CTYPE-X.509"

2293

":+CTYPE-OPENPGP:!RSA:+SIGN-DSA-SHA256",

2294

.current_server = NULL, .interfaces = NULL,

2295

.interfaces_size = 0 };

1909

mandos_context mc = { .server = NULL, .dh_bits = 1024,

1910

.priority = "SECURE256:!CTYPE-X.509:"

1911

"+CTYPE-OPENPGP", .current_server = NULL,

1912

.interfaces = NULL, .interfaces_size = 0 };

2296

1913

AvahiSServiceBrowser *sb = NULL;

2297

1914

error_t ret_errno;

2298

1915

int ret;

2307

1924

AvahiIfIndex if_index = AVAHI_IF_UNSPEC;

2308

1925

const char *seckey = PATHDIR "/" SECKEY;

2309

1926

const char *pubkey = PATHDIR "/" PUBKEY;

2310

const char *dh_params_file = NULL;

2311

1927

char *interfaces_hooks = NULL;

2312

1928

2313

1929

bool gnutls_initialized = false;

2366

1982

.doc = "Bit length of the prime number used in the"

2367

1983

" Diffie-Hellman key exchange",

2368

1984

.group = 2 },

2369

{ .name = "dh-params", .key = 134,

2370

.arg = "FILE",

2371

.doc = "PEM-encoded PKCS#3 file with pre-generated parameters"

2372

" for the Diffie-Hellman key exchange",

2373

.group = 2 },

2374

1985

{ .name = "priority", .key = 130,

2375

1986

.arg = "STRING",

2376

1987

.doc = "GnuTLS priority string for the TLS handshake",

2431

2042

}

2432

2043

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

2433

2044

break;

2434

case 134: /* --dh-params */

2435

dh_params_file = arg;

2436

break;

2437

2045

case 130: /* --priority */

2438

2046

mc.priority = arg;

2439

2047

break;

2495

2103

goto end;

2496

2104

}

2497

2105

}

2498

2106

2499

2107

{

2500

2108

/* Work around Debian bug #633582:

2501

2109

<http://bugs.debian.org/633582> */

2525

2133

}

2526

2134

}

2527

2135

}

2528

close(seckey_fd);

2136

TEMP_FAILURE_RETRY(close(seckey_fd));

2529

2137

}

2530

2138

}

2531

2139

2532

2140

if(strcmp(pubkey, PATHDIR "/" PUBKEY) == 0){

2533

2141

int pubkey_fd = open(pubkey, O_RDONLY);

2534

2142

if(pubkey_fd == -1){

2546

2154

}

2547

2155

}

2548

2156

}

2549

close(pubkey_fd);

2550

}

2551

}

2552

2553

if(dh_params_file != NULL

2554

and strcmp(dh_params_file, PATHDIR "/dhparams.pem" ) == 0){

2555

int dhparams_fd = open(dh_params_file, O_RDONLY);

2556

if(dhparams_fd == -1){

2557

perror_plus("open");

2558

} else {

2559

ret = (int)TEMP_FAILURE_RETRY(fstat(dhparams_fd, &st));

2560

if(ret == -1){

2561

perror_plus("fstat");

2562

} else {

2563

if(S_ISREG(st.st_mode)

2564

and st.st_uid == 0 and st.st_gid == 0){

2565

ret = fchown(dhparams_fd, uid, gid);

2566

if(ret == -1){

2567

perror_plus("fchown");

2568

}

2569

}

2570

}

2571

close(dhparams_fd);

2572

}

2573

}

2574

2157

TEMP_FAILURE_RETRY(close(pubkey_fd));

2158

}

2159

}

2160

2575

2161

/* Lower privileges */

2576

2162

ret_errno = lower_privileges();

2577

2163

if(ret_errno != 0){

2694

2280

2695

2281

/* If no interfaces were specified, make a list */

2696

2282

if(mc.interfaces == NULL){

2697

struct dirent **direntries = NULL;

2283

struct dirent **direntries;

2698

2284

/* Look for any good interfaces */

2699

2285

ret = scandir(sys_class_net, &direntries, good_interface,

2700

2286

alphasort);

2706

2292

if(ret_errno != 0){

2707

2293

errno = ret_errno;

2708

2294

perror_plus("argz_add");

2709

free(direntries[i]);

2710

2295

continue;

2711

2296

}

2712

2297

if(debug){

2713

2298

fprintf_plus(stderr, "Will use interface \"%s\"\n",

2714

2299

direntries[i]->d_name);

2715

2300

}

2716

free(direntries[i]);

2717

2301

}

2718

2302

free(direntries);

2719

2303

} else {

2720

if(ret == 0){

2721

free(direntries);

2722

}

2304

free(direntries);

2723

2305

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

2724

2306

exitcode = EXIT_FAILURE;

2725

2307

goto end;

2751

2333

errno = bring_up_interface(interface, delay);

2752

2334

if(not interface_was_up){

2753

2335

if(errno != 0){

2754

fprintf_plus(stderr, "Failed to bring up interface \"%s\":"

2755

" %s\n", interface, strerror(errno));

2336

perror_plus("Failed to bring up interface");

2756

2337

} else {

2757

2338

errno = argz_add(&interfaces_to_take_down,

2758

2339

&interfaces_to_take_down_size,

2781

2362

goto end;

2782

2363

}

2783

2364

2784

ret = init_gnutls_global(pubkey, seckey, dh_params_file, &mc);

2365

ret = init_gnutls_global(pubkey, seckey, &mc);

2785

2366

if(ret == -1){

2786

2367

fprintf_plus(stderr, "init_gnutls_global failed\n");

2787

2368

exitcode = EX_UNAVAILABLE;

2990

2571

mc.current_server->prev->next = NULL;

2991

2572

while(mc.current_server != NULL){

2992

2573

server *next = mc.current_server->next;

2993

#ifdef __GNUC__

2994

#pragma GCC diagnostic push

2995

#pragma GCC diagnostic ignored "-Wcast-qual"

2996

#endif

2997

free((char *)(mc.current_server->ip));

2998

#ifdef __GNUC__

2999

#pragma GCC diagnostic pop

3000

#endif

3001

2574

free(mc.current_server);

3002

2575

mc.current_server = next;

3003

2576

}

3007

2580

{

3008

2581

ret_errno = raise_privileges();

3009

2582

if(ret_errno != 0){

3010

errno = ret_errno;

3011

2583

perror_plus("Failed to raise privileges");

3012

2584

} else {

3013

2585

3036

2608

3037

2609

ret_errno = lower_privileges_permanently();

3038

2610

if(ret_errno != 0){

3039

errno = ret_errno;

3040

2611

perror_plus("Failed to lower privileges permanently");

3041

2612

}

3042

2613

}

3047

2618

/* Removes the GPGME temp directory and all files inside */

3048

2619

if(tempdir != NULL){

3049

2620

struct dirent **direntries = NULL;

3050

int tempdir_fd = (int)TEMP_FAILURE_RETRY(open(tempdir, O_RDONLY

3051

| O_NOFOLLOW

3052

| O_DIRECTORY

3053

| O_PATH));

2621

int tempdir_fd = (int)TEMP_FAILURE_RETRY(open(tempdir, O_RDONLY));

3054

2622

if(tempdir_fd == -1){

3055

2623

perror_plus("open");

3056

2624

} else {

3057

#ifdef __GLIBC__

3058

#if __GLIBC_PREREQ(2, 15)

3059

int numentries = scandirat(tempdir_fd, ".", &direntries,

3060

notdotentries, alphasort);

3061

#else /* not __GLIBC_PREREQ(2, 15) */

3062

int numentries = scandir(tempdir, &direntries, notdotentries,

3063

alphasort);

3064

#endif /* not __GLIBC_PREREQ(2, 15) */

3065

#else /* not __GLIBC__ */

3066

int numentries = scandir(tempdir, &direntries, notdotentries,

3067

alphasort);

3068

#endif /* not __GLIBC__ */

3069

if(numentries >= 0){

2625

int numentries = scandir(tempdir, &direntries, notdotentries,

2626

alphasort);

2627

if(numentries > 0){

3070

2628

for(int i = 0; i < numentries; i++){

3071

2629

ret = unlinkat(tempdir_fd, direntries[i]->d_name, 0);

3072

2630

if(ret == -1){

3074

2632

" \"%s\", 0): %s\n", tempdir,

3075

2633

direntries[i]->d_name, strerror(errno));

3076

2634

}

3077

free(direntries[i]);

3078

2635

}

3079

2636

3080

2637

/* need to clean even if 0 because man page doesn't specify */

3087

2644

perror_plus("rmdir");

3088

2645

}

3089

2646

}

3090

close(tempdir_fd);

2647

TEMP_FAILURE_RETRY(close(tempdir_fd));

3091

2648

}

3092

2649

}

3093

2650