/mandos/trunk : revision 893

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> /* memset(), strcmp(), strlen(),

50

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

49

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

50

asprintf(), strncpy(), strsignal()

51

*/

51

52

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

52

53

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

53

54

sockaddr_in6, PF_INET6,

57

58

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

58

59

inet_pton(), connect(),

59

60

getnameinfo() */

60

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

61

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

61

62

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

62

63

*/

63

64

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

64

65

strtoimax() */

65

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

66

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

67

EAI_SYSTEM, ENETUNREACH,

68

EHOSTUNREACH, ECONNREFUSED, EPROTO,

69

EIO, ENOENT, ENXIO, ENOMEM, EISDIR,

70

ENOTEMPTY,

66

71

program_invocation_short_name */

67

72

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

68

73

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

305

310

return false;

306

311

}

307

312

308

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

313

ret = close(fd);

309

314

if(ret == -1){

310

315

perror_plus("close");

311

316

}

493

498

return plaintext_length;

494

499

}

495

500

501

__attribute__((warn_unused_result, const))

502

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

503

if(str == NULL)

504

return "(unknown)";

505

return str;

506

}

507

496

508

__attribute__((warn_unused_result))

497

509

static const char *safer_gnutls_strerror(int value){

498

510

const char *ret = gnutls_strerror(value);

499

if(ret == NULL)

500

ret = "(unknown)";

501

return ret;

511

return safe_string(ret);

502

512

}

503

513

504

514

/* GnuTLS log function callback */

508

518

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

509

519

}

510

520

511

__attribute__((nonnull, warn_unused_result))

521

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

512

522

static int init_gnutls_global(const char *pubkeyfilename,

513

523

const char *seckeyfilename,

524

const char *dhparamsfilename,

514

525

mandos_context *mc){

515

526

int ret;

527

unsigned int uret;

516

528

517

529

if(debug){

518

530

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

519

531

}

520

532

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

533

if(debug){

529

534

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

530

535

* - GnuTLS manual

538

543

if(ret != GNUTLS_E_SUCCESS){

539

544

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

540

545

safer_gnutls_strerror(ret));

541

gnutls_global_deinit();

542

546

return -1;

543

547

}

544

548

569

573

safer_gnutls_strerror(ret));

570

574

goto globalfail;

571

575

}

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

576

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

577

if(dhparamsfilename != NULL){

578

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

579

do {

580

int dhpfile = open(dhparamsfilename, O_RDONLY);

581

if(dhpfile == -1){

582

perror_plus("open");

583

dhparamsfilename = NULL;

584

break;

585

}

586

size_t params_capacity = 0;

587

while(true){

588

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

589

(size_t)params.size,

590

(size_t)params_capacity);

591

if(params_capacity == 0){

592

perror_plus("incbuffer");

593

free(params.data);

594

params.data = NULL;

595

dhparamsfilename = NULL;

596

break;

597

}

598

ssize_t bytes_read = read(dhpfile,

599

params.data + params.size,

600

BUFFER_SIZE);

601

/* EOF */

602

if(bytes_read == 0){

603

break;

604

}

605

/* check bytes_read for failure */

606

if(bytes_read < 0){

607

perror_plus("read");

608

free(params.data);

609

params.data = NULL;

610

dhparamsfilename = NULL;

611

break;

612

}

613

params.size += (unsigned int)bytes_read;

614

}

615

if(params.data == NULL){

616

dhparamsfilename = NULL;

617

}

618

if(dhparamsfilename == NULL){

619

break;

620

}

621

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

622

GNUTLS_X509_FMT_PEM);

623

if(ret != GNUTLS_E_SUCCESS){

624

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

625

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

626

safer_gnutls_strerror(ret));

627

dhparamsfilename = NULL;

628

}

629

free(params.data);

630

} while(false);

631

}

632

if(dhparamsfilename == NULL){

633

if(mc->dh_bits == 0){

634

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

635

/* Try to read the private key file */

636

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

637

do {

638

int secfile = open(seckeyfilename, O_RDONLY);

639

if(secfile == -1){

640

perror_plus("open");

641

break;

642

}

643

size_t buffer_capacity = 0;

644

while(true){

645

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

646

(size_t)buffer.size,

647

(size_t)buffer_capacity);

648

if(buffer_capacity == 0){

649

perror_plus("incbuffer");

650

free(buffer.data);

651

buffer.data = NULL;

652

break;

653

}

654

ssize_t bytes_read = read(secfile,

655

buffer.data + buffer.size,

656

BUFFER_SIZE);

657

/* EOF */

658

if(bytes_read == 0){

659

break;

660

}

661

/* check bytes_read for failure */

662

if(bytes_read < 0){

663

perror_plus("read");

664

free(buffer.data);

665

buffer.data = NULL;

666

break;

667

}

668

buffer.size += (unsigned int)bytes_read;

669

}

670

close(secfile);

671

} while(false);

672

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

673

gnutls_sec_param_t sec_param = GNUTLS_SEC_PARAM_ULTRA;

674

if(buffer.data != NULL){

675

{

676

gnutls_openpgp_privkey_t privkey = NULL;

677

ret = gnutls_openpgp_privkey_init(&privkey);

678

if(ret != GNUTLS_E_SUCCESS){

679

fprintf_plus(stderr, "Error initializing OpenPGP key"

680

" structure: %s",

681

safer_gnutls_strerror(ret));

682

free(buffer.data);

683

buffer.data = NULL;

684

} else {

685

ret = gnutls_openpgp_privkey_import

686

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

687

if(ret != GNUTLS_E_SUCCESS){

688

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

689

safer_gnutls_strerror(ret));

690

privkey = NULL;

691

}

692

free(buffer.data);

693

buffer.data = NULL;

694

if(privkey != NULL){

695

/* Use private key to suggest an appropriate

696

sec_param */

697

sec_param = gnutls_openpgp_privkey_sec_param(privkey);

698

gnutls_openpgp_privkey_deinit(privkey);

699

if(debug){

700

fprintf_plus(stderr, "This OpenPGP key implies using"

701

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

702

safe_string(gnutls_sec_param_get_name

703

(sec_param)));

704

}

705

}

706

}

707

}

708

if(sec_param == GNUTLS_SEC_PARAM_UNKNOWN){

709

/* Err on the side of caution */

710

sec_param = GNUTLS_SEC_PARAM_ULTRA;

711

if(debug){

712

fprintf_plus(stderr, "Falling back to security parameter"

713

" \"%s\"\n",

714

safe_string(gnutls_sec_param_get_name

715

(sec_param)));

716

}

717

}

718

}

719

uret = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, sec_param);

720

if(uret != 0){

721

mc->dh_bits = uret;

722

if(debug){

723

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

724

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

725

safe_string(gnutls_sec_param_get_name

726

(sec_param)),

727

mc->dh_bits);

728

}

729

} else {

730

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

731

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

732

safe_string(gnutls_sec_param_get_name

733

(sec_param)),

734

safer_gnutls_strerror(ret));

735

goto globalfail;

736

}

737

} else if(debug){

738

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

739

mc->dh_bits);

740

}

741

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

742

if(ret != GNUTLS_E_SUCCESS){

743

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

744

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

745

safer_gnutls_strerror(ret));

746

goto globalfail;

747

}

748

}

579

749

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

580

750

581

751

return 0;

583

753

globalfail:

584

754

585

755

gnutls_certificate_free_credentials(mc->cred);

586

gnutls_global_deinit();

587

756

gnutls_dh_params_deinit(mc->dh_params);

588

757

return -1;

589

758

}

641

810

/* ignore client certificate if any. */

642

811

gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);

643

812

644

gnutls_dh_set_prime_bits(*session, mc->dh_bits);

645

646

813

return 0;

647

814

}

648

815

650

817

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

651

818

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

652

819

820

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

821

__attribute__((warn_unused_result))

822

int raise_privileges(void){

823

int old_errno = errno;

824

int ret = 0;

825

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

826

ret = errno;

827

}

828

errno = old_errno;

829

return ret;

830

}

831

832

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

833

__attribute__((warn_unused_result))

834

int raise_privileges_permanently(void){

835

int old_errno = errno;

836

int ret = raise_privileges();

837

if(ret != 0){

838

errno = old_errno;

839

return ret;

840

}

841

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

842

ret = errno;

843

}

844

errno = old_errno;

845

return ret;

846

}

847

848

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

849

__attribute__((warn_unused_result))

850

int lower_privileges(void){

851

int old_errno = errno;

852

int ret = 0;

853

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

854

ret = errno;

855

}

856

errno = old_errno;

857

return ret;

858

}

859

860

/* Lower privileges permanently */

861

__attribute__((warn_unused_result))

862

int lower_privileges_permanently(void){

863

int old_errno = errno;

864

int ret = 0;

865

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

866

ret = errno;

867

}

868

errno = old_errno;

869

return ret;

870

}

871

872

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

873

__attribute__((nonnull, warn_unused_result))

874

static bool add_delete_local_route(const bool add,

875

const char *address,

876

AvahiIfIndex if_index){

877

int ret;

878

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

879

char add_arg[] = "add";

880

char delete_arg[] = "delete";

881

char debug_flag[] = "--debug";

882

char *pluginhelperdir = getenv("MANDOSPLUGINHELPERDIR");

883

if(pluginhelperdir == NULL){

884

if(debug){

885

fprintf_plus(stderr, "MANDOSPLUGINHELPERDIR environment"

886

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

887

}

888

return false;

889

}

890

891

char interface[IF_NAMESIZE];

892

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

893

perror_plus("if_indextoname");

894

return false;

895

}

896

897

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

898

if(devnull == -1){

899

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

900

return false;

901

}

902

pid_t pid = fork();

903

if(pid == 0){

904

/* Child */

905

/* Raise privileges */

906

errno = raise_privileges_permanently();

907

if(errno != 0){

908

perror_plus("Failed to raise privileges");

909

/* _exit(EX_NOPERM); */

910

} else {

911

/* Set group */

912

errno = 0;

913

ret = setgid(0);

914

if(ret == -1){

915

perror_plus("setgid");

916

_exit(EX_NOPERM);

917

}

918

/* Reset supplementary groups */

919

errno = 0;

920

ret = setgroups(0, NULL);

921

if(ret == -1){

922

perror_plus("setgroups");

923

_exit(EX_NOPERM);

924

}

925

}

926

ret = dup2(devnull, STDIN_FILENO);

927

if(ret == -1){

928

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

929

_exit(EX_OSERR);

930

}

931

ret = close(devnull);

932

if(ret == -1){

933

perror_plus("close");

934

_exit(EX_OSERR);

935

}

936

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

937

if(ret == -1){

938

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

939

_exit(EX_OSERR);

940

}

941

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

942

O_RDONLY

943

| O_DIRECTORY

944

| O_PATH

945

| O_CLOEXEC));

946

if(helperdir_fd == -1){

947

perror_plus("open");

948

_exit(EX_UNAVAILABLE);

949

}

950

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

951

helper, O_RDONLY));

952

if(helper_fd == -1){

953

perror_plus("openat");

954

close(helperdir_fd);

955

_exit(EX_UNAVAILABLE);

956

}

957

close(helperdir_fd);

958

#ifdef __GNUC__

959

#pragma GCC diagnostic push

960

#pragma GCC diagnostic ignored "-Wcast-qual"

961

#endif

962

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

963

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

964

interface, debug ? debug_flag : NULL, NULL },

965

environ) == -1){

966

#ifdef __GNUC__

967

#pragma GCC diagnostic pop

968

#endif

969

perror_plus("fexecve");

970

_exit(EXIT_FAILURE);

971

}

972

}

973

if(pid == -1){

974

perror_plus("fork");

975

return false;

976

}

977

int status;

978

pid_t pret = -1;

979

errno = 0;

980

do {

981

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

982

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

983

int errno_raising = 0;

984

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

985

errno_raising = errno;

986

perror_plus("Failed to raise privileges in order to"

987

" kill helper program");

988

}

989

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

990

perror_plus("kill");

991

}

992

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

993

perror_plus("Failed to lower privileges after killing"

994

" helper program");

995

}

996

return false;

997

}

998

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

999

if(pret == -1){

1000

perror_plus("waitpid");

1001

return false;

1002

}

1003

if(WIFEXITED(status)){

1004

if(WEXITSTATUS(status) != 0){

1005

fprintf_plus(stderr, "Error: iprouteadddel exited"

1006

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

1007

return false;

1008

}

1009

return true;

1010

}

1011

if(WIFSIGNALED(status)){

1012

fprintf_plus(stderr, "Error: iprouteadddel died by"

1013

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

1014

return false;

1015

}

1016

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

1017

return false;

1018

}

1019

1020

__attribute__((nonnull, warn_unused_result))

1021

static bool add_local_route(const char *address,

1022

AvahiIfIndex if_index){

1023

if(debug){

1024

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

1025

}

1026

return add_delete_local_route(true, address, if_index);

1027

}

1028

1029

__attribute__((nonnull, warn_unused_result))

1030

static bool delete_local_route(const char *address,

1031

AvahiIfIndex if_index){

1032

if(debug){

1033

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

1034

}

1035

return add_delete_local_route(false, address, if_index);

1036

}

1037

653

1038

/* Called when a Mandos server is found */

654

1039

__attribute__((nonnull, warn_unused_result))

655

1040

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

666

1051

int retval = -1;

667

1052

gnutls_session_t session;

668

1053

int pf; /* Protocol family */

1054

bool route_added = false;

669

1055

670

1056

errno = 0;

671

1057

693

1079

bool match = false;

694

1080

{

695

1081

char *interface = NULL;

696

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

697

interface))){

1082

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

1083

mc->interfaces_size,

1084

interface))){

698

1085

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

699

1086

match = true;

700

1087

break;

729

1116

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

730

1117

}

731

1118

732

tcp_sd = socket(pf, SOCK_STREAM, 0);

1119

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

733

1120

if(tcp_sd < 0){

734

1121

int e = errno;

735

1122

perror_plus("socket");

742

1129

goto mandos_end;

743

1130

}

744

1131

745

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

746

1132

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);

1133

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

1134

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

1135

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

749

1136

} 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);

1137

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

1138

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

1139

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

752

1140

}

753

1141

if(ret < 0 ){

754

1142

int e = errno;

824

1212

goto mandos_end;

825

1213

}

826

1214

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;

1215

while(true){

1216

if(af == AF_INET6){

1217

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

1218

sizeof(struct sockaddr_in6));

1219

} else {

1220

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

1221

sizeof(struct sockaddr_in));

1222

}

1223

if(ret < 0){

1224

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

1225

and if_index != AVAHI_IF_UNSPEC

1226

and connect_to == NULL

1227

and not route_added and

1228

((af == AF_INET6 and not

1229

IN6_IS_ADDR_LINKLOCAL(&(((struct sockaddr_in6 *)

1230

&to)->sin6_addr)))

1231

or (af == AF_INET and

1232

/* Not a a IPv4LL address */

1233

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

1234

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

1235

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

1236

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

1237

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

1238

connect to a Mandos server announced by Avahi on a server

1239

host with a global address. Work around this by retrying

1240

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

1241

1242

Avahi bug reference:

1243

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

1244

https://bugs.debian.org/587961

1245

*/

1246

if(debug){

1247

fprintf_plus(stderr, "Mandos server unreachable, trying"

1248

" direct route\n");

1249

}

1250

int e = errno;

1251

route_added = add_local_route(ip, if_index);

1252

if(route_added){

1253

continue;

1254

}

1255

errno = e;

1256

}

1257

if(errno != ECONNREFUSED or debug){

1258

int e = errno;

1259

perror_plus("connect");

1260

errno = e;

1261

}

1262

goto mandos_end;

1263

}

1264

1265

if(quit_now){

1266

errno = EINTR;

1267

goto mandos_end;

1268

}

1269

break;

846

1270

}

847

1271

848

1272

const char *out = mandos_protocol_version;

1002

1426

&decrypted_buffer, mc);

1003

1427

if(decrypted_buffer_size >= 0){

1004

1428

1429

clearerr(stdout);

1005

1430

written = 0;

1006

1431

while(written < (size_t) decrypted_buffer_size){

1007

1432

if(quit_now){

1023

1448

}

1024

1449

written += (size_t)ret;

1025

1450

}

1451

ret = fflush(stdout);

1452

if(ret != 0){

1453

int e = errno;

1454

if(debug){

1455

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

1456

strerror(errno));

1457

}

1458

errno = e;

1459

goto mandos_end;

1460

}

1026

1461

retval = 0;

1027

1462

}

1028

1463

}

1031

1466

1032

1467

mandos_end:

1033

1468

{

1469

if(route_added){

1470

if(not delete_local_route(ip, if_index)){

1471

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

1472

" interface %d", ip, if_index);

1473

}

1474

}

1034

1475

int e = errno;

1035

1476

free(decrypted_buffer);

1036

1477

free(buffer);

1037

1478

if(tcp_sd >= 0){

1038

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

1479

ret = close(tcp_sd);

1039

1480

}

1040

1481

if(ret == -1){

1041

1482

if(e == 0){

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)

1537

1926

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

1538

1927

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

1928

if(numhooks == -1){

1548

1929

perror_plus("scandir");

1549

1930

return;

1550

1931

}

1551

1932

struct dirent *direntry;

1552

1933

int ret;

1553

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

1934

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

1935

if(devnull == -1){

1936

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

1937

return;

1938

}

1554

1939

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

1555

1940

direntry = direntries[i];

1556

1941

if(debug){

1580

1965

perror_plus("setgroups");

1581

1966

_exit(EX_NOPERM);

1582

1967

}

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

1968

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

1599

1969

if(ret == -1){

1600

1970

perror_plus("setenv");

1635

2005

_exit(EX_OSERR);

1636

2006

}

1637

2007

}

1638

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

2008

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

2009

direntry->d_name,

2010

O_RDONLY));

1639

2011

if(hook_fd == -1){

1640

2012

perror_plus("openat");

1641

2013

_exit(EXIT_FAILURE);

1642

2014

}

1643

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

2015

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

1644

2016

perror_plus("close");

1645

2017

_exit(EXIT_FAILURE);

1646

2018

}

2019

ret = dup2(devnull, STDIN_FILENO);

2020

if(ret == -1){

2021

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

2022

_exit(EX_OSERR);

2023

}

2024

ret = close(devnull);

2025

if(ret == -1){

2026

perror_plus("close");

2027

_exit(EX_OSERR);

2028

}

2029

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

2030

if(ret == -1){

2031

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

2032

_exit(EX_OSERR);

2033

}

1647

2034

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

1648

2035

environ) == -1){

1649

2036

perror_plus("fexecve");

1689

2076

free(direntry);

1690

2077

}

1691

2078

free(direntries);

1692

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

2079

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

1693

2080

perror_plus("close");

1694

2081

} else {

1695

2082

hookdir_fd = -1;

1698

2085

}

1699

2086

1700

2087

__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;

2088

int bring_up_interface(const char *const interface,

2089

const float delay){

2090

int old_errno = errno;

1704

2091

int ret;

1705

2092

struct ifreq network;

1706

2093

unsigned int if_index = if_nametoindex(interface);

1716

2103

}

1717

2104

1718

2105

if(not interface_is_up(interface)){

1719

error_t ret_errno = 0, ioctl_errno = 0;

2106

int ret_errno = 0;

2107

int ioctl_errno = 0;

1720

2108

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

1721

2109

ret_errno = errno;

1722

2110

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

1735

2123

}

1736

2124

1737

2125

if(quit_now){

1738

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

2126

ret = close(sd);

1739

2127

if(ret == -1){

1740

2128

perror_plus("close");

1741

2129

}

1791

2179

}

1792

2180

1793

2181

/* Close the socket */

1794

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

2182

ret = close(sd);

1795

2183

if(ret == -1){

1796

2184

perror_plus("close");

1797

2185

}

1809

2197

1810

2198

/* Sleep checking until interface is running.

1811

2199

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

1812

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

2200

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

1813

2201

if(interface_is_running(interface)){

1814

2202

break;

1815

2203

}

1825

2213

}

1826

2214

1827

2215

__attribute__((nonnull, warn_unused_result))

1828

error_t take_down_interface(const char *const interface){

1829

error_t old_errno = errno;

2216

int take_down_interface(const char *const interface){

2217

int old_errno = errno;

1830

2218

struct ifreq network;

1831

2219

unsigned int if_index = if_nametoindex(interface);

1832

2220

if(if_index == 0){

1835

2223

return ENXIO;

1836

2224

}

1837

2225

if(interface_is_up(interface)){

1838

error_t ret_errno = 0, ioctl_errno = 0;

2226

int ret_errno = 0;

2227

int ioctl_errno = 0;

1839

2228

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

1840

2229

ret_errno = errno;

1841

2230

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

1879

2268

}

1880

2269

1881

2270

/* Close the socket */

1882

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

2271

int ret = close(sd);

1883

2272

if(ret == -1){

1884

2273

perror_plus("close");

1885

2274

}

1900

2289

}

1901

2290

1902

2291

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 };

2292

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

2293

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

2294

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

2295

.current_server = NULL, .interfaces = NULL,

2296

.interfaces_size = 0 };

1907

2297

AvahiSServiceBrowser *sb = NULL;

1908

2298

error_t ret_errno;

1909

2299

int ret;

1918

2308

AvahiIfIndex if_index = AVAHI_IF_UNSPEC;

1919

2309

const char *seckey = PATHDIR "/" SECKEY;

1920

2310

const char *pubkey = PATHDIR "/" PUBKEY;

2311

const char *dh_params_file = NULL;

1921

2312

char *interfaces_hooks = NULL;

1922

2313

1923

2314

bool gnutls_initialized = false;

1976

2367

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

1977

2368

" Diffie-Hellman key exchange",

1978

2369

.group = 2 },

2370

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

2371

.arg = "FILE",

2372

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

2373

" for the Diffie-Hellman key exchange",

2374

.group = 2 },

1979

2375

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

1980

2376

.arg = "STRING",

1981

2377

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

2036

2432

}

2037

2433

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

2038

2434

break;

2435

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

2436

dh_params_file = arg;

2437

break;

2039

2438

case 130: /* --priority */

2040

2439

mc.priority = arg;

2041

2440

break;

2081

2480

.args_doc = "",

2082

2481

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

2083

2482

" passwords from a Mandos server" };

2084

ret = argp_parse(&argp, argc, argv,

2085

ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);

2086

switch(ret){

2483

ret_errno = argp_parse(&argp, argc, argv,

2484

ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);

2485

switch(ret_errno){

2087

2486

case 0:

2088

2487

break;

2089

2488

case ENOMEM:

2090

2489

default:

2091

errno = ret;

2490

errno = ret_errno;

2092

2491

perror_plus("argp_parse");

2093

2492

exitcode = EX_OSERR;

2094

2493

goto end;

2097

2496

goto end;

2098

2497

}

2099

2498

}

2100

2499

2101

2500

{

2102

2501

/* Work around Debian bug #633582:

2103

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

2502

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

2104

2503

2105

2504

/* Re-raise privileges */

2106

ret_errno = raise_privileges();

2107

if(ret_errno != 0){

2108

errno = ret_errno;

2505

ret = raise_privileges();

2506

if(ret != 0){

2507

errno = ret;

2109

2508

perror_plus("Failed to raise privileges");

2110

2509

} else {

2111

2510

struct stat st;

2127

2526

}

2128

2527

}

2129

2528

}

2130

TEMP_FAILURE_RETRY(close(seckey_fd));

2529

close(seckey_fd);

2131

2530

}

2132

2531

}

2133

2532

2134

2533

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

2135

2534

int pubkey_fd = open(pubkey, O_RDONLY);

2136

2535

if(pubkey_fd == -1){

2148

2547

}

2149

2548

}

2150

2549

}

2151

TEMP_FAILURE_RETRY(close(pubkey_fd));

2152

}

2153

}

2154

2550

close(pubkey_fd);

2551

}

2552

}

2553

2554

if(dh_params_file != NULL

2555

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

2556

int dhparams_fd = open(dh_params_file, O_RDONLY);

2557

if(dhparams_fd == -1){

2558

perror_plus("open");

2559

} else {

2560

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

2561

if(ret == -1){

2562

perror_plus("fstat");

2563

} else {

2564

if(S_ISREG(st.st_mode)

2565

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

2566

ret = fchown(dhparams_fd, uid, gid);

2567

if(ret == -1){

2568

perror_plus("fchown");

2569

}

2570

}

2571

}

2572

close(dhparams_fd);

2573

}

2574

}

2575

2155

2576

/* Lower privileges */

2156

ret_errno = lower_privileges();

2157

if(ret_errno != 0){

2158

errno = ret_errno;

2577

ret = lower_privileges();

2578

if(ret != 0){

2579

errno = ret;

2159

2580

perror_plus("Failed to lower privileges");

2160

2581

}

2161

2582

}

2331

2752

errno = bring_up_interface(interface, delay);

2332

2753

if(not interface_was_up){

2333

2754

if(errno != 0){

2334

perror_plus("Failed to bring up interface");

2755

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

2756

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

2335

2757

} else {

2336

2758

errno = argz_add(&interfaces_to_take_down,

2337

2759

&interfaces_to_take_down_size,

2360

2782

goto end;

2361

2783

}

2362

2784

2363

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

2785

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

2364

2786

if(ret == -1){

2365

2787

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

2366

2788

exitcode = EX_UNAVAILABLE;

2488

2910

2489

2911

/* Allocate a new server */

2490

2912

mc.server = avahi_server_new(avahi_simple_poll_get(simple_poll),

2491

&config, NULL, NULL, &ret_errno);

2913

&config, NULL, NULL, &ret);

2492

2914

2493

2915

/* Free the Avahi configuration data */

2494

2916

avahi_server_config_free(&config);

2497

2919

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

2498

2920

if(mc.server == NULL){

2499

2921

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

2500

avahi_strerror(ret_errno));

2922

avahi_strerror(ret));

2501

2923

exitcode = EX_UNAVAILABLE;

2502

2924

goto end;

2503

2925

}

2538

2960

end:

2539

2961

2540

2962

if(debug){

2541

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

2963

if(signal_received){

2964

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

2965

argv[0], signal_received,

2966

strsignal(signal_received));

2967

} else {

2968

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

2969

}

2542

2970

}

2543

2971

2544

2972

/* Cleanup things */

2555

2983

2556

2984

if(gnutls_initialized){

2557

2985

gnutls_certificate_free_credentials(mc.cred);

2558

gnutls_global_deinit();

2559

2986

gnutls_dh_params_deinit(mc.dh_params);

2560

2987

}

2561

2988

2584

3011

2585

3012

/* Re-raise privileges */

2586

3013

{

2587

ret_errno = raise_privileges();

2588

if(ret_errno != 0){

2589

errno = ret_errno;

3014

ret = raise_privileges();

3015

if(ret != 0){

3016

errno = ret;

2590

3017

perror_plus("Failed to raise privileges");

2591

3018

} else {

2592

3019

2597

3024

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

2598

3025

{

2599

3026

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;

3027

while((interface = argz_next(interfaces_to_take_down,

3028

interfaces_to_take_down_size,

3029

interface))){

3030

ret = take_down_interface(interface);

3031

if(ret != 0){

3032

errno = ret;

2606

3033

perror_plus("Failed to take down interface");

2607

3034

}

2608

3035

}

2613

3040

}

2614

3041

}

2615

3042

2616

ret_errno = lower_privileges_permanently();

2617

if(ret_errno != 0){

2618

errno = ret_errno;

3043

ret = lower_privileges_permanently();

3044

if(ret != 0){

3045

errno = ret;

2619

3046

perror_plus("Failed to lower privileges permanently");

2620

3047

}

2621

3048

}

2623

3050

free(interfaces_to_take_down);

2624

3051

free(interfaces_hooks);

2625

3052

3053

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

3054

uintmax_t level){

3055

struct dirent **direntries = NULL;

3056

int dret;

3057

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

3058

O_RDONLY

3059

| O_NOFOLLOW

3060

| O_DIRECTORY

3061

| O_PATH));

3062

if(dir_fd == -1){

3063

perror_plus("open");

3064

}

3065

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

3066

notdotentries, alphasort);

3067

if(numentries >= 0){

3068

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

3069

if(debug){

3070

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

3071

dirname, direntries[i]->d_name);

3072

}

3073

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

3074

if(dret == -1){

3075

if(errno == EISDIR){

3076

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

3077

AT_REMOVEDIR);

3078

}

3079

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

3080

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

3081

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

3082

/* Recurse only in this special case */

3083

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

3084

dret = 0;

3085

}

3086

if(dret == -1){

3087

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

3088

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

3089

}

3090

}

3091

free(direntries[i]);

3092

}

3093

3094

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

3095

free(direntries);

3096

if(numentries == -1){

3097

perror_plus("scandirat");

3098

}

3099

dret = unlinkat(base, dirname, AT_REMOVEDIR);

3100

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

3101

perror_plus("rmdir");

3102

}

3103

} else {

3104

perror_plus("scandirat");

3105

}

3106

close(dir_fd);

3107

}

3108

2626

3109

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

2627

3110

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

}

3111

clean_dir_at(-1, tempdir, 0);

2669

3112

}

2670

3113

2671

3114

if(quit_now){