/mandos/trunk : revision 938

9

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

10

*

11

* Everything else is

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

17

* published by the Free Software Foundation, either version 3 of the

18

* License, or (at your option) any later version.

19

*

20

* This program is distributed in the hope that it will be useful, but

12

13

14

*

15

* This file is part of Mandos.

16

*

17

* Mandos is free software: you can redistribute it and/or modify it

18

* under the terms of the GNU General Public License as published by

19

* the Free Software Foundation, either version 3 of the License, or

20

* (at your option) any later version.

21

*

22

* Mandos is distributed in the hope that it will be useful, but

21

23

* WITHOUT ANY WARRANTY; without even the implied warranty of

22

24

* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

23

25

* General Public License for more details.

24

26

*

25

27

* You should have received a copy of the GNU General Public License

26

* along with this program. If not, see

27

* <http://www.gnu.org/licenses/>.

28

* along with Mandos. If not, see <http://www.gnu.org/licenses/>.

28

29

*

29

30

* Contact the authors at <mandos@recompile.se>.

30

31

*/

46

47

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

47

48

strtof(), abort() */

48

49

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

49

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

50

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

50

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

51

asprintf(), strncpy(), strsignal()

52

*/

51

53

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

52

54

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

53

55

sockaddr_in6, PF_INET6,

57

59

#include <sys/socket.h> /* socket(), struct sockaddr_in6,

58

60

inet_pton(), connect(),

59

61

getnameinfo() */

60

#include <fcntl.h> /* open(), unlinkat() */

62

#include <fcntl.h> /* open(), unlinkat(), AT_REMOVEDIR */

61

63

#include <dirent.h> /* opendir(), struct dirent, readdir()

62

64

*/

63

65

#include <inttypes.h> /* PRIu16, PRIdMAX, intmax_t,

64

66

strtoimax() */

65

#include <errno.h> /* perror(), errno,

67

#include <errno.h> /* perror(), errno, EINTR, EINVAL,

68

EAI_SYSTEM, ENETUNREACH,

69

EHOSTUNREACH, ECONNREFUSED, EPROTO,

70

EIO, ENOENT, ENXIO, ENOMEM, EISDIR,

71

ENOTEMPTY,

66

72

program_invocation_short_name */

67

73

#include <time.h> /* nanosleep(), time(), sleep() */

68

74

#include <net/if.h> /* ioctl, ifreq, SIOCGIFFLAGS, IFF_UP,

305

311

return false;

306

312

}

307

313

308

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

314

ret = close(fd);

309

315

if(ret == -1){

310

316

perror_plus("close");

311

317

}

493

499

return plaintext_length;

494

500

}

495

501

502

__attribute__((warn_unused_result, const))

503

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

504

if(str == NULL)

505

return "(unknown)";

506

return str;

507

}

508

496

509

__attribute__((warn_unused_result))

497

510

static const char *safer_gnutls_strerror(int value){

498

511

const char *ret = gnutls_strerror(value);

499

if(ret == NULL)

500

ret = "(unknown)";

501

return ret;

512

return safe_string(ret);

502

513

}

503

514

504

515

/* GnuTLS log function callback */

508

519

fprintf_plus(stderr, "GnuTLS: %s", string);

509

520

}

510

521

511

__attribute__((nonnull, warn_unused_result))

522

__attribute__((nonnull(1, 2, 4), warn_unused_result))

512

523

static int init_gnutls_global(const char *pubkeyfilename,

513

524

const char *seckeyfilename,

525

const char *dhparamsfilename,

514

526

mandos_context *mc){

515

527

int ret;

528

unsigned int uret;

516

529

517

530

if(debug){

518

531

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

519

532

}

520

533

521

ret = gnutls_global_init();

522

if(ret != GNUTLS_E_SUCCESS){

523

fprintf_plus(stderr, "GnuTLS global_init: %s\n",

524

safer_gnutls_strerror(ret));

525

return -1;

526

}

527

528

534

if(debug){

529

535

/* "Use a log level over 10 to enable all debugging options."

530

536

* - GnuTLS manual

538

544

if(ret != GNUTLS_E_SUCCESS){

539

545

fprintf_plus(stderr, "GnuTLS memory error: %s\n",

540

546

safer_gnutls_strerror(ret));

541

gnutls_global_deinit();

542

547

return -1;

543

548

}

544

549

569

574

safer_gnutls_strerror(ret));

570

575

goto globalfail;

571

576

}

572

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

573

if(ret != GNUTLS_E_SUCCESS){

574

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

575

safer_gnutls_strerror(ret));

576

goto globalfail;

577

}

578

577

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

578

if(dhparamsfilename != NULL){

579

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

580

do {

581

int dhpfile = open(dhparamsfilename, O_RDONLY);

582

if(dhpfile == -1){

583

perror_plus("open");

584

dhparamsfilename = NULL;

585

break;

586

}

587

size_t params_capacity = 0;

588

while(true){

589

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

590

(size_t)params.size,

591

(size_t)params_capacity);

592

if(params_capacity == 0){

593

perror_plus("incbuffer");

594

free(params.data);

595

params.data = NULL;

596

dhparamsfilename = NULL;

597

break;

598

}

599

ssize_t bytes_read = read(dhpfile,

600

params.data + params.size,

601

BUFFER_SIZE);

602

/* EOF */

603

if(bytes_read == 0){

604

break;

605

}

606

/* check bytes_read for failure */

607

if(bytes_read < 0){

608

perror_plus("read");

609

free(params.data);

610

params.data = NULL;

611

dhparamsfilename = NULL;

612

break;

613

}

614

params.size += (unsigned int)bytes_read;

615

}

616

if(params.data == NULL){

617

dhparamsfilename = NULL;

618

}

619

if(dhparamsfilename == NULL){

620

break;

621

}

622

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

623

GNUTLS_X509_FMT_PEM);

624

if(ret != GNUTLS_E_SUCCESS){

625

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

626

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

627

safer_gnutls_strerror(ret));

628

dhparamsfilename = NULL;

629

}

630

free(params.data);

631

} while(false);

632

}

633

if(dhparamsfilename == NULL){

634

if(mc->dh_bits == 0){

635

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

636

/* Try to read the private key file */

637

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

638

do {

639

int secfile = open(seckeyfilename, O_RDONLY);

640

if(secfile == -1){

641

perror_plus("open");

642

break;

643

}

644

size_t buffer_capacity = 0;

645

while(true){

646

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

647

(size_t)buffer.size,

648

(size_t)buffer_capacity);

649

if(buffer_capacity == 0){

650

perror_plus("incbuffer");

651

free(buffer.data);

652

buffer.data = NULL;

653

break;

654

}

655

ssize_t bytes_read = read(secfile,

656

buffer.data + buffer.size,

657

BUFFER_SIZE);

658

/* EOF */

659

if(bytes_read == 0){

660

break;

661

}

662

/* check bytes_read for failure */

663

if(bytes_read < 0){

664

perror_plus("read");

665

free(buffer.data);

666

buffer.data = NULL;

667

break;

668

}

669

buffer.size += (unsigned int)bytes_read;

670

}

671

close(secfile);

672

} while(false);

673

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

674

gnutls_sec_param_t sec_param = GNUTLS_SEC_PARAM_ULTRA;

675

if(buffer.data != NULL){

676

{

677

gnutls_openpgp_privkey_t privkey = NULL;

678

ret = gnutls_openpgp_privkey_init(&privkey);

679

if(ret != GNUTLS_E_SUCCESS){

680

fprintf_plus(stderr, "Error initializing OpenPGP key"

681

" structure: %s",

682

safer_gnutls_strerror(ret));

683

free(buffer.data);

684

buffer.data = NULL;

685

} else {

686

ret = gnutls_openpgp_privkey_import

687

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

688

if(ret != GNUTLS_E_SUCCESS){

689

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

690

safer_gnutls_strerror(ret));

691

privkey = NULL;

692

}

693

free(buffer.data);

694

buffer.data = NULL;

695

if(privkey != NULL){

696

/* Use private key to suggest an appropriate

697

sec_param */

698

sec_param = gnutls_openpgp_privkey_sec_param(privkey);

699

gnutls_openpgp_privkey_deinit(privkey);

700

if(debug){

701

fprintf_plus(stderr, "This OpenPGP key implies using"

702

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

703

safe_string(gnutls_sec_param_get_name

704

(sec_param)));

705

}

706

}

707

}

708

}

709

if(sec_param == GNUTLS_SEC_PARAM_UNKNOWN){

710

/* Err on the side of caution */

711

sec_param = GNUTLS_SEC_PARAM_ULTRA;

712

if(debug){

713

fprintf_plus(stderr, "Falling back to security parameter"

714

" \"%s\"\n",

715

safe_string(gnutls_sec_param_get_name

716

(sec_param)));

717

}

718

}

719

}

720

uret = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, sec_param);

721

if(uret != 0){

722

mc->dh_bits = uret;

723

if(debug){

724

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

725

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

726

safe_string(gnutls_sec_param_get_name

727

(sec_param)),

728

mc->dh_bits);

729

}

730

} else {

731

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

732

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

733

safe_string(gnutls_sec_param_get_name

734

(sec_param)),

735

safer_gnutls_strerror(ret));

736

goto globalfail;

737

}

738

} else if(debug){

739

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

740

mc->dh_bits);

741

}

742

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

743

if(ret != GNUTLS_E_SUCCESS){

744

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

745

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

746

safer_gnutls_strerror(ret));

747

goto globalfail;

748

}

749

}

579

750

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

580

751

581

752

return 0;

583

754

globalfail:

584

755

585

756

gnutls_certificate_free_credentials(mc->cred);

586

gnutls_global_deinit();

587

757

gnutls_dh_params_deinit(mc->dh_params);

588

758

return -1;

589

759

}

641

811

/* ignore client certificate if any. */

642

812

gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);

643

813

644

gnutls_dh_set_prime_bits(*session, mc->dh_bits);

645

646

814

return 0;

647

815

}

648

816

650

818

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

651

819

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

652

820

821

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

822

__attribute__((warn_unused_result))

823

int raise_privileges(void){

824

int old_errno = errno;

825

int ret = 0;

826

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

827

ret = errno;

828

}

829

errno = old_errno;

830

return ret;

831

}

832

833

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

834

__attribute__((warn_unused_result))

835

int raise_privileges_permanently(void){

836

int old_errno = errno;

837

int ret = raise_privileges();

838

if(ret != 0){

839

errno = old_errno;

840

return ret;

841

}

842

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

843

ret = errno;

844

}

845

errno = old_errno;

846

return ret;

847

}

848

849

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

850

__attribute__((warn_unused_result))

851

int lower_privileges(void){

852

int old_errno = errno;

853

int ret = 0;

854

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

855

ret = errno;

856

}

857

errno = old_errno;

858

return ret;

859

}

860

861

/* Lower privileges permanently */

862

__attribute__((warn_unused_result))

863

int lower_privileges_permanently(void){

864

int old_errno = errno;

865

int ret = 0;

866

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

867

ret = errno;

868

}

869

errno = old_errno;

870

return ret;

871

}

872

873

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

874

__attribute__((nonnull, warn_unused_result))

875

static bool add_delete_local_route(const bool add,

876

const char *address,

877

AvahiIfIndex if_index){

878

int ret;

879

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

880

char add_arg[] = "add";

881

char delete_arg[] = "delete";

882

char debug_flag[] = "--debug";

883

char *pluginhelperdir = getenv("MANDOSPLUGINHELPERDIR");

884

if(pluginhelperdir == NULL){

885

if(debug){

886

fprintf_plus(stderr, "MANDOSPLUGINHELPERDIR environment"

887

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

888

}

889

return false;

890

}

891

892

char interface[IF_NAMESIZE];

893

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

894

perror_plus("if_indextoname");

895

return false;

896

}

897

898

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

899

if(devnull == -1){

900

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

901

return false;

902

}

903

pid_t pid = fork();

904

if(pid == 0){

905

/* Child */

906

/* Raise privileges */

907

errno = raise_privileges_permanently();

908

if(errno != 0){

909

perror_plus("Failed to raise privileges");

910

/* _exit(EX_NOPERM); */

911

} else {

912

/* Set group */

913

errno = 0;

914

ret = setgid(0);

915

if(ret == -1){

916

perror_plus("setgid");

917

_exit(EX_NOPERM);

918

}

919

/* Reset supplementary groups */

920

errno = 0;

921

ret = setgroups(0, NULL);

922

if(ret == -1){

923

perror_plus("setgroups");

924

_exit(EX_NOPERM);

925

}

926

}

927

ret = dup2(devnull, STDIN_FILENO);

928

if(ret == -1){

929

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

930

_exit(EX_OSERR);

931

}

932

ret = close(devnull);

933

if(ret == -1){

934

perror_plus("close");

935

_exit(EX_OSERR);

936

}

937

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

938

if(ret == -1){

939

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

940

_exit(EX_OSERR);

941

}

942

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

943

O_RDONLY

944

| O_DIRECTORY

945

| O_PATH

946

| O_CLOEXEC));

947

if(helperdir_fd == -1){

948

perror_plus("open");

949

_exit(EX_UNAVAILABLE);

950

}

951

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

952

helper, O_RDONLY));

953

if(helper_fd == -1){

954

perror_plus("openat");

955

close(helperdir_fd);

956

_exit(EX_UNAVAILABLE);

957

}

958

close(helperdir_fd);

959

#ifdef __GNUC__

960

#pragma GCC diagnostic push

961

#pragma GCC diagnostic ignored "-Wcast-qual"

962

#endif

963

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

964

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

965

interface, debug ? debug_flag : NULL, NULL },

966

environ) == -1){

967

#ifdef __GNUC__

968

#pragma GCC diagnostic pop

969

#endif

970

perror_plus("fexecve");

971

_exit(EXIT_FAILURE);

972

}

973

}

974

if(pid == -1){

975

perror_plus("fork");

976

return false;

977

}

978

int status;

979

pid_t pret = -1;

980

errno = 0;

981

do {

982

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

983

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

984

int errno_raising = 0;

985

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

986

errno_raising = errno;

987

perror_plus("Failed to raise privileges in order to"

988

" kill helper program");

989

}

990

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

991

perror_plus("kill");

992

}

993

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

994

perror_plus("Failed to lower privileges after killing"

995

" helper program");

996

}

997

return false;

998

}

999

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

1000

if(pret == -1){

1001

perror_plus("waitpid");

1002

return false;

1003

}

1004

if(WIFEXITED(status)){

1005

if(WEXITSTATUS(status) != 0){

1006

fprintf_plus(stderr, "Error: iprouteadddel exited"

1007

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

1008

return false;

1009

}

1010

return true;

1011

}

1012

if(WIFSIGNALED(status)){

1013

fprintf_plus(stderr, "Error: iprouteadddel died by"

1014

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

1015

return false;

1016

}

1017

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

1018

return false;

1019

}

1020

1021

__attribute__((nonnull, warn_unused_result))

1022

static bool add_local_route(const char *address,

1023

AvahiIfIndex if_index){

1024

if(debug){

1025

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

1026

}

1027

return add_delete_local_route(true, address, if_index);

1028

}

1029

1030

__attribute__((nonnull, warn_unused_result))

1031

static bool delete_local_route(const char *address,

1032

AvahiIfIndex if_index){

1033

if(debug){

1034

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

1035

}

1036

return add_delete_local_route(false, address, if_index);

1037

}

1038

653

1039

/* Called when a Mandos server is found */

654

1040

__attribute__((nonnull, warn_unused_result))

655

1041

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

666

1052

int retval = -1;

667

1053

gnutls_session_t session;

668

1054

int pf; /* Protocol family */

1055

bool route_added = false;

669

1056

670

1057

errno = 0;

671

1058

693

1080

bool match = false;

694

1081

{

695

1082

char *interface = NULL;

696

while((interface=argz_next(mc->interfaces, mc->interfaces_size,

697

interface))){

1083

while((interface = argz_next(mc->interfaces,

1084

mc->interfaces_size,

1085

interface))){

698

1086

if(if_nametoindex(interface) == (unsigned int)if_index){

699

1087

match = true;

700

1088

break;

729

1117

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

730

1118

}

731

1119

732

tcp_sd = socket(pf, SOCK_STREAM, 0);

1120

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

733

1121

if(tcp_sd < 0){

734

1122

int e = errno;

735

1123

perror_plus("socket");

742

1130

goto mandos_end;

743

1131

}

744

1132

745

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

746

1133

if(af == AF_INET6){

747

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

748

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

1134

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

1135

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

1136

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

749

1137

} else { /* IPv4 */

750

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

751

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

1138

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

1139

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

1140

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

752

1141

}

753

1142

if(ret < 0 ){

754

1143

int e = errno;

824

1213

goto mandos_end;

825

1214

}

826

1215

827

if(af == AF_INET6){

828

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

829

sizeof(struct sockaddr_in6));

830

} else {

831

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

832

sizeof(struct sockaddr_in));

833

}

834

if(ret < 0){

835

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

836

int e = errno;

837

perror_plus("connect");

838

errno = e;

839

}

840

goto mandos_end;

841

}

842

843

if(quit_now){

844

errno = EINTR;

845

goto mandos_end;

1216

while(true){

1217

if(af == AF_INET6){

1218

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

1219

sizeof(struct sockaddr_in6));

1220

} else {

1221

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

1222

sizeof(struct sockaddr_in));

1223

}

1224

if(ret < 0){

1225

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

1226

and if_index != AVAHI_IF_UNSPEC

1227

and connect_to == NULL

1228

and not route_added and

1229

((af == AF_INET6 and not

1230

IN6_IS_ADDR_LINKLOCAL(&(((struct sockaddr_in6 *)

1231

&to)->sin6_addr)))

1232

or (af == AF_INET and

1233

/* Not a a IPv4LL address */

1234

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

1235

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

1236

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

1237

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

1238

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

1239

connect to a Mandos server announced by Avahi on a server

1240

host with a global address. Work around this by retrying

1241

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

1242

1243

Avahi bug reference:

1244

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

1245

https://bugs.debian.org/587961

1246

*/

1247

if(debug){

1248

fprintf_plus(stderr, "Mandos server unreachable, trying"

1249

" direct route\n");

1250

}

1251

int e = errno;

1252

route_added = add_local_route(ip, if_index);

1253

if(route_added){

1254

continue;

1255

}

1256

errno = e;

1257

}

1258

if(errno != ECONNREFUSED or debug){

1259

int e = errno;

1260

perror_plus("connect");

1261

errno = e;

1262

}

1263

goto mandos_end;

1264

}

1265

1266

if(quit_now){

1267

errno = EINTR;

1268

goto mandos_end;

1269

}

1270

break;

846

1271

}

847

1272

848

1273

const char *out = mandos_protocol_version;

1002

1427

&decrypted_buffer, mc);

1003

1428

if(decrypted_buffer_size >= 0){

1004

1429

1430

clearerr(stdout);

1005

1431

written = 0;

1006

1432

while(written < (size_t) decrypted_buffer_size){

1007

1433

if(quit_now){

1023

1449

}

1024

1450

written += (size_t)ret;

1025

1451

}

1452

ret = fflush(stdout);

1453

if(ret != 0){

1454

int e = errno;

1455

if(debug){

1456

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

1457

strerror(errno));

1458

}

1459

errno = e;

1460

goto mandos_end;

1461

}

1026

1462

retval = 0;

1027

1463

}

1028

1464

}

1031

1467

1032

1468

mandos_end:

1033

1469

{

1470

if(route_added){

1471

if(not delete_local_route(ip, if_index)){

1472

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

1473

" interface %d", ip, if_index);

1474

}

1475

}

1034

1476

int e = errno;

1035

1477

free(decrypted_buffer);

1036

1478

free(buffer);

1037

1479

if(tcp_sd >= 0){

1038

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

1480

ret = close(tcp_sd);

1039

1481

}

1040

1482

if(ret == -1){

1041

1483

if(e == 0){

1053

1495

return retval;

1054

1496

}

1055

1497

1056

__attribute__((nonnull))

1057

1498

static void resolve_callback(AvahiSServiceResolver *r,

1058

1499

AvahiIfIndex interface,

1059

1500

AvahiProtocol proto,

1196

1637

__attribute__((nonnull, warn_unused_result))

1197

1638

bool get_flags(const char *ifname, struct ifreq *ifr){

1198

1639

int ret;

1199

error_t ret_errno;

1640

int old_errno;

1200

1641

1201

1642

int s = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP);

1202

1643

if(s < 0){

1203

ret_errno = errno;

1644

old_errno = errno;

1204

1645

perror_plus("socket");

1205

errno = ret_errno;

1646

errno = old_errno;

1206

1647

return false;

1207

1648

}

1208

strcpy(ifr->ifr_name, ifname);

1649

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

1650

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

1209

1651

ret = ioctl(s, SIOCGIFFLAGS, ifr);

1210

1652

if(ret == -1){

1211

1653

if(debug){

1212

ret_errno = errno;

1654

old_errno = errno;

1213

1655

perror_plus("ioctl SIOCGIFFLAGS");

1214

errno = ret_errno;

1656

errno = old_errno;

1215

1657

}

1216

1658

return false;

1217

1659

}

1462

1904

}

1463

1905

}

1464

1906

1465

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

1466

__attribute__((warn_unused_result))

1467

error_t raise_privileges(void){

1468

error_t old_errno = errno;

1469

error_t ret_errno = 0;

1470

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

1471

ret_errno = errno;

1472

}

1473

errno = old_errno;

1474

return ret_errno;

1475

}

1476

1477

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

1478

__attribute__((warn_unused_result))

1479

error_t raise_privileges_permanently(void){

1480

error_t old_errno = errno;

1481

error_t ret_errno = raise_privileges();

1482

if(ret_errno != 0){

1483

errno = old_errno;

1484

return ret_errno;

1485

}

1486

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

1487

ret_errno = errno;

1488

}

1489

errno = old_errno;

1490

return ret_errno;

1491

}

1492

1493

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

1494

__attribute__((warn_unused_result))

1495

error_t lower_privileges(void){

1496

error_t old_errno = errno;

1497

error_t ret_errno = 0;

1498

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

1499

ret_errno = errno;

1500

}

1501

errno = old_errno;

1502

return ret_errno;

1503

}

1504

1505

/* Lower privileges permanently */

1506

__attribute__((warn_unused_result))

1507

error_t lower_privileges_permanently(void){

1508

error_t old_errno = errno;

1509

error_t ret_errno = 0;

1510

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

1511

ret_errno = errno;

1512

}

1513

errno = old_errno;

1514

return ret_errno;

1515

}

1516

1517

1907

__attribute__((nonnull))

1518

1908

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

1519

1909

const float delay){

1520

1910

struct dirent **direntries = NULL;

1521

1911

if(hookdir_fd == -1){

1522

hookdir_fd = open(hookdir, O_RDONLY);

1912

hookdir_fd = open(hookdir, O_RDONLY | O_DIRECTORY | O_PATH

1913

| O_CLOEXEC);

1523

1914

if(hookdir_fd == -1){

1524

1915

if(errno == ENOENT){

1525

1916

if(debug){

1532

1923

return;

1533

1924

}

1534

1925

}

1535

#ifdef __GLIBC__

1536

#if __GLIBC_PREREQ(2, 15)

1926

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

1927

if(devnull == -1){

1928

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

1929

return;

1930

}

1537

1931

int numhooks = scandirat(hookdir_fd, ".", &direntries,

1538

1932

runnable_hook, alphasort);

1539

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

1540

int numhooks = scandir(hookdir, &direntries, runnable_hook,

1541

alphasort);

1542

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

1543

#else /* not __GLIBC__ */

1544

int numhooks = scandir(hookdir, &direntries, runnable_hook,

1545

alphasort);

1546

#endif /* not __GLIBC__ */

1547

1933

if(numhooks == -1){

1548

1934

perror_plus("scandir");

1935

close(devnull);

1549

1936

return;

1550

1937

}

1551

1938

struct dirent *direntry;

1552

1939

int ret;

1553

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

1554

1940

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

1555

1941

direntry = direntries[i];

1556

1942

if(debug){

1580

1966

perror_plus("setgroups");

1581

1967

_exit(EX_NOPERM);

1582

1968

}

1583

ret = dup2(devnull, STDIN_FILENO);

1584

if(ret == -1){

1585

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

1586

_exit(EX_OSERR);

1587

}

1588

ret = close(devnull);

1589

if(ret == -1){

1590

perror_plus("close");

1591

_exit(EX_OSERR);

1592

}

1593

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

1594

if(ret == -1){

1595

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

1596

_exit(EX_OSERR);

1597

}

1598

1969

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

1599

1970

if(ret == -1){

1600

1971

perror_plus("setenv");

1635

2006

_exit(EX_OSERR);

1636

2007

}

1637

2008

}

1638

int hook_fd = openat(hookdir_fd, direntry->d_name, O_RDONLY);

2009

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

2010

direntry->d_name,

2011

O_RDONLY));

1639

2012

if(hook_fd == -1){

1640

2013

perror_plus("openat");

1641

2014

_exit(EXIT_FAILURE);

1642

2015

}

1643

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

2016

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

1644

2017

perror_plus("close");

1645

2018

_exit(EXIT_FAILURE);

1646

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

}

1647

2035

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

1648

2036

environ) == -1){

1649

2037

perror_plus("fexecve");

1689

2077

free(direntry);

1690

2078

}

1691

2079

free(direntries);

1692

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

2080

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

1693

2081

perror_plus("close");

1694

2082

} else {

1695

2083

hookdir_fd = -1;

1698

2086

}

1699

2087

1700

2088

__attribute__((nonnull, warn_unused_result))

1701

error_t bring_up_interface(const char *const interface,

1702

const float delay){

1703

error_t old_errno = errno;

2089

int bring_up_interface(const char *const interface,

2090

const float delay){

2091

int old_errno = errno;

1704

2092

int ret;

1705

2093

struct ifreq network;

1706

2094

unsigned int if_index = if_nametoindex(interface);

1716

2104

}

1717

2105

1718

2106

if(not interface_is_up(interface)){

1719

error_t ret_errno = 0, ioctl_errno = 0;

2107

int ret_errno = 0;

2108

int ioctl_errno = 0;

1720

2109

if(not get_flags(interface, &network)){

1721

2110

ret_errno = errno;

1722

2111

fprintf_plus(stderr, "Failed to get flags for interface "

1735

2124

}

1736

2125

1737

2126

if(quit_now){

1738

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

2127

ret = close(sd);

1739

2128

if(ret == -1){

1740

2129

perror_plus("close");

1741

2130

}

1791

2180

}

1792

2181

1793

2182

/* Close the socket */

1794

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

2183

ret = close(sd);

1795

2184

if(ret == -1){

1796

2185

perror_plus("close");

1797

2186

}

1809

2198

1810

2199

/* Sleep checking until interface is running.

1811

2200

Check every 0.25s, up to total time of delay */

1812

for(int i=0; i < delay * 4; i++){

2201

for(int i = 0; i < delay * 4; i++){

1813

2202

if(interface_is_running(interface)){

1814

2203

break;

1815

2204

}

1825

2214

}

1826

2215

1827

2216

__attribute__((nonnull, warn_unused_result))

1828

error_t take_down_interface(const char *const interface){

1829

error_t old_errno = errno;

2217

int take_down_interface(const char *const interface){

2218

int old_errno = errno;

1830

2219

struct ifreq network;

1831

2220

unsigned int if_index = if_nametoindex(interface);

1832

2221

if(if_index == 0){

1835

2224

return ENXIO;

1836

2225

}

1837

2226

if(interface_is_up(interface)){

1838

error_t ret_errno = 0, ioctl_errno = 0;

2227

int ret_errno = 0;

2228

int ioctl_errno = 0;

1839

2229

if(not get_flags(interface, &network) and debug){

1840

2230

ret_errno = errno;

1841

2231

fprintf_plus(stderr, "Failed to get flags for interface "

1879

2269

}

1880

2270

1881

2271

/* Close the socket */

1882

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

2272

int ret = close(sd);

1883

2273

if(ret == -1){

1884

2274

perror_plus("close");

1885

2275

}

1900

2290

}

1901

2291

1902

2292

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

1903

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

1904

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

1905

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

1906

.interfaces = NULL, .interfaces_size = 0 };

2293

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

2294

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

2295

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

2296

.current_server = NULL, .interfaces = NULL,

2297

.interfaces_size = 0 };

1907

2298

AvahiSServiceBrowser *sb = NULL;

1908

2299

error_t ret_errno;

1909

2300

int ret;

1918

2309

AvahiIfIndex if_index = AVAHI_IF_UNSPEC;

1919

2310

const char *seckey = PATHDIR "/" SECKEY;

1920

2311

const char *pubkey = PATHDIR "/" PUBKEY;

2312

const char *dh_params_file = NULL;

1921

2313

char *interfaces_hooks = NULL;

1922

2314

1923

2315

bool gnutls_initialized = false;

1976

2368

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

1977

2369

" Diffie-Hellman key exchange",

1978

2370

.group = 2 },

2371

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

2372

.arg = "FILE",

2373

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

2374

" for the Diffie-Hellman key exchange",

2375

.group = 2 },

1979

2376

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

1980

2377

.arg = "STRING",

1981

2378

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

2036

2433

}

2037

2434

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

2038

2435

break;

2436

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

2437

dh_params_file = arg;

2438

break;

2039

2439

case 130: /* --priority */

2040

2440

mc.priority = arg;

2041

2441

break;

2081

2481

.args_doc = "",

2082

2482

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

2083

2483

" passwords from a Mandos server" };

2084

ret = argp_parse(&argp, argc, argv,

2085

ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);

2086

switch(ret){

2484

ret_errno = argp_parse(&argp, argc, argv,

2485

ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);

2486

switch(ret_errno){

2087

2487

case 0:

2088

2488

break;

2089

2489

case ENOMEM:

2090

2490

default:

2091

errno = ret;

2491

errno = ret_errno;

2092

2492

perror_plus("argp_parse");

2093

2493

exitcode = EX_OSERR;

2094

2494

goto end;

2097

2497

goto end;

2098

2498

}

2099

2499

}

2100

2500

2101

2501

{

2102

2502

/* Work around Debian bug #633582:

2103

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

2503

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

2104

2504

2105

2505

/* Re-raise privileges */

2106

ret_errno = raise_privileges();

2107

if(ret_errno != 0){

2108

errno = ret_errno;

2506

ret = raise_privileges();

2507

if(ret != 0){

2508

errno = ret;

2109

2509

perror_plus("Failed to raise privileges");

2110

2510

} else {

2111

2511

struct stat st;

2127

2527

}

2128

2528

}

2129

2529

}

2130

TEMP_FAILURE_RETRY(close(seckey_fd));

2530

close(seckey_fd);

2131

2531

}

2132

2532

}

2133

2533

2134

2534

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

2135

2535

int pubkey_fd = open(pubkey, O_RDONLY);

2136

2536

if(pubkey_fd == -1){

2148

2548

}

2149

2549

}

2150

2550

}

2151

TEMP_FAILURE_RETRY(close(pubkey_fd));

2152

}

2153

}

2154

2551

close(pubkey_fd);

2552

}

2553

}

2554

2555

if(dh_params_file != NULL

2556

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

2557

int dhparams_fd = open(dh_params_file, O_RDONLY);

2558

if(dhparams_fd == -1){

2559

perror_plus("open");

2560

} else {

2561

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

2562

if(ret == -1){

2563

perror_plus("fstat");

2564

} else {

2565

if(S_ISREG(st.st_mode)

2566

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

2567

ret = fchown(dhparams_fd, uid, gid);

2568

if(ret == -1){

2569

perror_plus("fchown");

2570

}

2571

}

2572

}

2573

close(dhparams_fd);

2574

}

2575

}

2576

2155

2577

/* Lower privileges */

2156

ret_errno = lower_privileges();

2157

if(ret_errno != 0){

2158

errno = ret_errno;

2578

ret = lower_privileges();

2579

if(ret != 0){

2580

errno = ret;

2159

2581

perror_plus("Failed to lower privileges");

2160

2582

}

2161

2583

}

2331

2753

errno = bring_up_interface(interface, delay);

2332

2754

if(not interface_was_up){

2333

2755

if(errno != 0){

2334

perror_plus("Failed to bring up interface");

2756

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

2757

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

2335

2758

} else {

2336

2759

errno = argz_add(&interfaces_to_take_down,

2337

2760

&interfaces_to_take_down_size,

2360

2783

goto end;

2361

2784

}

2362

2785

2363

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

2786

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

2364

2787

if(ret == -1){

2365

2788

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

2366

2789

exitcode = EX_UNAVAILABLE;

2488

2911

2489

2912

/* Allocate a new server */

2490

2913

mc.server = avahi_server_new(avahi_simple_poll_get(simple_poll),

2491

&config, NULL, NULL, &ret_errno);

2914

&config, NULL, NULL, &ret);

2492

2915

2493

2916

/* Free the Avahi configuration data */

2494

2917

avahi_server_config_free(&config);

2497

2920

/* Check if creating the Avahi server object succeeded */

2498

2921

if(mc.server == NULL){

2499

2922

fprintf_plus(stderr, "Failed to create Avahi server: %s\n",

2500

avahi_strerror(ret_errno));

2923

avahi_strerror(ret));

2501

2924

exitcode = EX_UNAVAILABLE;

2502

2925

goto end;

2503

2926

}

2538

2961

end:

2539

2962

2540

2963

if(debug){

2541

fprintf_plus(stderr, "%s exiting\n", argv[0]);

2964

if(signal_received){

2965

fprintf_plus(stderr, "%s exiting due to signal %d: %s\n",

2966

argv[0], signal_received,

2967

strsignal(signal_received));

2968

} else {

2969

fprintf_plus(stderr, "%s exiting\n", argv[0]);

2970

}

2542

2971

}

2543

2972

2544

2973

/* Cleanup things */

2555

2984

2556

2985

if(gnutls_initialized){

2557

2986

gnutls_certificate_free_credentials(mc.cred);

2558

gnutls_global_deinit();

2559

2987

gnutls_dh_params_deinit(mc.dh_params);

2560

2988

}

2561

2989

2584

3012

2585

3013

/* Re-raise privileges */

2586

3014

{

2587

ret_errno = raise_privileges();

2588

if(ret_errno != 0){

2589

errno = ret_errno;

3015

ret = raise_privileges();

3016

if(ret != 0){

3017

errno = ret;

2590

3018

perror_plus("Failed to raise privileges");

2591

3019

} else {

2592

3020

2597

3025

/* Take down the network interfaces which were brought up */

2598

3026

{

2599

3027

char *interface = NULL;

2600

while((interface=argz_next(interfaces_to_take_down,

2601

interfaces_to_take_down_size,

2602

interface))){

2603

ret_errno = take_down_interface(interface);

2604

if(ret_errno != 0){

2605

errno = ret_errno;

3028

while((interface = argz_next(interfaces_to_take_down,

3029

interfaces_to_take_down_size,

3030

interface))){

3031

ret = take_down_interface(interface);

3032

if(ret != 0){

3033

errno = ret;

2606

3034

perror_plus("Failed to take down interface");

2607

3035

}

2608

3036

}

2613

3041

}

2614

3042

}

2615

3043

2616

ret_errno = lower_privileges_permanently();

2617

if(ret_errno != 0){

2618

errno = ret_errno;

3044

ret = lower_privileges_permanently();

3045

if(ret != 0){

3046

errno = ret;

2619

3047

perror_plus("Failed to lower privileges permanently");

2620

3048

}

2621

3049

}

2623

3051

free(interfaces_to_take_down);

2624

3052

free(interfaces_hooks);

2625

3053

3054

void clean_dir_at(int base, const char * const dirname,

3055

uintmax_t level){

3056

struct dirent **direntries = NULL;

3057

int dret;

3058

int dir_fd = (int)TEMP_FAILURE_RETRY(openat(base, dirname,

3059

O_RDONLY

3060

| O_NOFOLLOW

3061

| O_DIRECTORY

3062

| O_PATH));

3063

if(dir_fd == -1){

3064

perror_plus("open");

3065

return;

3066

}

3067

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

3068

notdotentries, alphasort);

3069

if(numentries >= 0){

3070

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

3071

if(debug){

3072

fprintf_plus(stderr, "Unlinking \"%s/%s\"\n",

3073

dirname, direntries[i]->d_name);

3074

}

3075

dret = unlinkat(dir_fd, direntries[i]->d_name, 0);

3076

if(dret == -1){

3077

if(errno == EISDIR){

3078

dret = unlinkat(dir_fd, direntries[i]->d_name,

3079

AT_REMOVEDIR);

3080

}

3081

if((dret == -1) and (errno == ENOTEMPTY)

3082

and (strcmp(direntries[i]->d_name, "private-keys-v1.d")

3083

== 0) and (level == 0)){

3084

/* Recurse only in this special case */

3085

clean_dir_at(dir_fd, direntries[i]->d_name, level+1);

3086

dret = 0;

3087

}

3088

if((dret == -1) and (errno != ENOENT)){

3089

fprintf_plus(stderr, "unlink(\"%s/%s\"): %s\n", dirname,

3090

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

3091

}

3092

}

3093

free(direntries[i]);

3094

}

3095

3096

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

3097

free(direntries);

3098

dret = unlinkat(base, dirname, AT_REMOVEDIR);

3099

if(dret == -1 and errno != ENOENT){

3100

perror_plus("rmdir");

3101

}

3102

} else {

3103

perror_plus("scandirat");

3104

}

3105

close(dir_fd);

3106

}

3107

2626

3108

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

2627

3109

if(tempdir != NULL){

2628

struct dirent **direntries = NULL;

2629

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

2630

O_NOFOLLOW));

2631

if(tempdir_fd == -1){

2632

perror_plus("open");

2633

} else {

2634

#ifdef __GLIBC__

2635

#if __GLIBC_PREREQ(2, 15)

2636

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

2637

notdotentries, alphasort);

2638

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

2639

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

2640

alphasort);

2641

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

2642

#else /* not __GLIBC__ */

2643

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

2644

alphasort);

2645

#endif /* not __GLIBC__ */

2646

if(numentries >= 0){

2647

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

2648

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

2649

if(ret == -1){

2650

fprintf_plus(stderr, "unlinkat(open(\"%s\", O_RDONLY),"

2651

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

2652

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

2653

}

2654

free(direntries[i]);

2655

}

2656

2657

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

2658

free(direntries);

2659

if(numentries == -1){

2660

perror_plus("scandir");

2661

}

2662

ret = rmdir(tempdir);

2663

if(ret == -1 and errno != ENOENT){

2664

perror_plus("rmdir");

2665

}

2666

}

2667

TEMP_FAILURE_RETRY(close(tempdir_fd));

2668

}

3110

clean_dir_at(-1, tempdir, 0);

2669

3111

}

2670

3112

2671

3113

if(quit_now){