/mandos/trunk : revision 812

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() */

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);

237

238

return false;

238

239

}

239

240

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

240

241

if(ret == -1){

241

242

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);

242

252

return false;

243

253

}

244

254

/* Special case of first server */

295

305

return false;

296

306

}

297

307

298

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

308

ret = close(fd);

299

309

if(ret == -1){

300

310

perror_plus("close");

301

311

}

483

493

return plaintext_length;

484

494

}

485

495

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

486

503

__attribute__((warn_unused_result))

487

504

static const char *safer_gnutls_strerror(int value){

488

505

const char *ret = gnutls_strerror(value);

489

if(ret == NULL)

490

ret = "(unknown)";

491

return ret;

506

return safe_string(ret);

492

507

}

493

508

494

509

/* GnuTLS log function callback */

498

513

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

499

514

}

500

515

501

__attribute__((nonnull, warn_unused_result))

516

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

502

517

static int init_gnutls_global(const char *pubkeyfilename,

503

518

const char *seckeyfilename,

519

const char *dhparamsfilename,

504

520

mandos_context *mc){

505

521

int ret;

522

unsigned int uret;

506

523

507

524

if(debug){

508

525

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

509

526

}

510

527

511

ret = gnutls_global_init();

512

if(ret != GNUTLS_E_SUCCESS){

513

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

514

safer_gnutls_strerror(ret));

515

return -1;

516

}

517

518

528

if(debug){

519

529

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

520

530

* - GnuTLS manual

528

538

if(ret != GNUTLS_E_SUCCESS){

529

539

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

530

540

safer_gnutls_strerror(ret));

531

gnutls_global_deinit();

532

541

return -1;

533

542

}

534

543

559

568

safer_gnutls_strerror(ret));

560

569

goto globalfail;

561

570

}

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

571

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

572

if(dhparamsfilename != NULL){

573

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

574

do {

575

int dhpfile = open(dhparamsfilename, O_RDONLY);

576

if(dhpfile == -1){

577

perror_plus("open");

578

dhparamsfilename = NULL;

579

break;

580

}

581

size_t params_capacity = 0;

582

while(true){

583

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

584

(size_t)params.size,

585

(size_t)params_capacity);

586

if(params_capacity == 0){

587

perror_plus("incbuffer");

588

free(params.data);

589

params.data = NULL;

590

dhparamsfilename = NULL;

591

break;

592

}

593

ssize_t bytes_read = read(dhpfile,

594

params.data + params.size,

595

BUFFER_SIZE);

596

/* EOF */

597

if(bytes_read == 0){

598

break;

599

}

600

/* check bytes_read for failure */

601

if(bytes_read < 0){

602

perror_plus("read");

603

free(params.data);

604

params.data = NULL;

605

dhparamsfilename = NULL;

606

break;

607

}

608

params.size += (unsigned int)bytes_read;

609

}

610

if(params.data == NULL){

611

dhparamsfilename = NULL;

612

}

613

if(dhparamsfilename == NULL){

614

break;

615

}

616

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

617

GNUTLS_X509_FMT_PEM);

618

if(ret != GNUTLS_E_SUCCESS){

619

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

620

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

621

safer_gnutls_strerror(ret));

622

dhparamsfilename = NULL;

623

}

624

} while(false);

625

}

626

if(dhparamsfilename == NULL){

627

if(mc->dh_bits == 0){

628

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

629

/* Try to read the private key file */

630

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

631

do {

632

int secfile = open(seckeyfilename, O_RDONLY);

633

if(secfile == -1){

634

perror_plus("open");

635

break;

636

}

637

size_t buffer_capacity = 0;

638

while(true){

639

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

640

(size_t)buffer.size,

641

(size_t)buffer_capacity);

642

if(buffer_capacity == 0){

643

perror_plus("incbuffer");

644

free(buffer.data);

645

buffer.data = NULL;

646

break;

647

}

648

ssize_t bytes_read = read(secfile,

649

buffer.data + buffer.size,

650

BUFFER_SIZE);

651

/* EOF */

652

if(bytes_read == 0){

653

break;

654

}

655

/* check bytes_read for failure */

656

if(bytes_read < 0){

657

perror_plus("read");

658

free(buffer.data);

659

buffer.data = NULL;

660

break;

661

}

662

buffer.size += (unsigned int)bytes_read;

663

}

664

close(secfile);

665

} while(false);

666

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

667

gnutls_sec_param_t sec_param = GNUTLS_SEC_PARAM_ULTRA;

668

if(buffer.data != NULL){

669

{

670

gnutls_openpgp_privkey_t privkey = NULL;

671

ret = gnutls_openpgp_privkey_init(&privkey);

672

if(ret != GNUTLS_E_SUCCESS){

673

fprintf_plus(stderr, "Error initializing OpenPGP key"

674

" structure: %s",

675

safer_gnutls_strerror(ret));

676

free(buffer.data);

677

buffer.data = NULL;

678

} else {

679

ret = gnutls_openpgp_privkey_import

680

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

681

if(ret != GNUTLS_E_SUCCESS){

682

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

683

safer_gnutls_strerror(ret));

684

privkey = NULL;

685

}

686

free(buffer.data);

687

buffer.data = NULL;

688

if(privkey != NULL){

689

/* Use private key to suggest an appropriate

690

sec_param */

691

sec_param = gnutls_openpgp_privkey_sec_param(privkey);

692

gnutls_openpgp_privkey_deinit(privkey);

693

if(debug){

694

fprintf_plus(stderr, "This OpenPGP key implies using"

695

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

696

safe_string(gnutls_sec_param_get_name

697

(sec_param)));

698

}

699

}

700

}

701

}

702

if(sec_param == GNUTLS_SEC_PARAM_UNKNOWN){

703

/* Err on the side of caution */

704

sec_param = GNUTLS_SEC_PARAM_ULTRA;

705

if(debug){

706

fprintf_plus(stderr, "Falling back to security parameter"

707

" \"%s\"\n",

708

safe_string(gnutls_sec_param_get_name

709

(sec_param)));

710

}

711

}

712

}

713

uret = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, sec_param);

714

if(uret != 0){

715

mc->dh_bits = uret;

716

if(debug){

717

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

718

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

719

safe_string(gnutls_sec_param_get_name

720

(sec_param)),

721

mc->dh_bits);

722

}

723

} else {

724

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

725

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

726

safe_string(gnutls_sec_param_get_name

727

(sec_param)),

728

safer_gnutls_strerror(ret));

729

goto globalfail;

730

}

731

} else if(debug){

732

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

733

mc->dh_bits);

734

}

735

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

736

if(ret != GNUTLS_E_SUCCESS){

737

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

738

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

739

safer_gnutls_strerror(ret));

740

goto globalfail;

741

}

742

}

569

743

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

570

744

571

745

return 0;

573

747

globalfail:

574

748

575

749

gnutls_certificate_free_credentials(mc->cred);

576

gnutls_global_deinit();

577

750

gnutls_dh_params_deinit(mc->dh_params);

578

751

return -1;

579

752

}

631

804

/* ignore client certificate if any. */

632

805

gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);

633

806

634

gnutls_dh_set_prime_bits(*session, mc->dh_bits);

635

636

807

return 0;

637

808

}

638

809

640

811

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

641

812

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

642

813

814

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

815

__attribute__((warn_unused_result))

816

error_t raise_privileges(void){

817

error_t old_errno = errno;

818

error_t ret_errno = 0;

819

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

820

ret_errno = errno;

821

}

822

errno = old_errno;

823

return ret_errno;

824

}

825

826

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

827

__attribute__((warn_unused_result))

828

error_t raise_privileges_permanently(void){

829

error_t old_errno = errno;

830

error_t ret_errno = raise_privileges();

831

if(ret_errno != 0){

832

errno = old_errno;

833

return ret_errno;

834

}

835

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

836

ret_errno = errno;

837

}

838

errno = old_errno;

839

return ret_errno;

840

}

841

842

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

843

__attribute__((warn_unused_result))

844

error_t lower_privileges(void){

845

error_t old_errno = errno;

846

error_t ret_errno = 0;

847

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

848

ret_errno = errno;

849

}

850

errno = old_errno;

851

return ret_errno;

852

}

853

854

/* Lower privileges permanently */

855

__attribute__((warn_unused_result))

856

error_t lower_privileges_permanently(void){

857

error_t old_errno = errno;

858

error_t ret_errno = 0;

859

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

860

ret_errno = errno;

861

}

862

errno = old_errno;

863

return ret_errno;

864

}

865

866

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

867

__attribute__((nonnull, warn_unused_result))

868

static bool add_delete_local_route(const bool add,

869

const char *address,

870

AvahiIfIndex if_index){

871

int ret;

872

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

873

char add_arg[] = "add";

874

char delete_arg[] = "delete";

875

char debug_flag[] = "--debug";

876

char *pluginhelperdir = getenv("MANDOSPLUGINHELPERDIR");

877

if(pluginhelperdir == NULL){

878

if(debug){

879

fprintf_plus(stderr, "MANDOSPLUGINHELPERDIR environment"

880

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

881

}

882

return false;

883

}

884

885

char interface[IF_NAMESIZE];

886

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

887

perror_plus("if_indextoname");

888

return false;

889

}

890

891

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

892

if(devnull == -1){

893

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

894

return false;

895

}

896

pid_t pid = fork();

897

if(pid == 0){

898

/* Child */

899

/* Raise privileges */

900

errno = raise_privileges_permanently();

901

if(errno != 0){

902

perror_plus("Failed to raise privileges");

903

/* _exit(EX_NOPERM); */

904

} else {

905

/* Set group */

906

errno = 0;

907

ret = setgid(0);

908

if(ret == -1){

909

perror_plus("setgid");

910

_exit(EX_NOPERM);

911

}

912

/* Reset supplementary groups */

913

errno = 0;

914

ret = setgroups(0, NULL);

915

if(ret == -1){

916

perror_plus("setgroups");

917

_exit(EX_NOPERM);

918

}

919

}

920

ret = dup2(devnull, STDIN_FILENO);

921

if(ret == -1){

922

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

923

_exit(EX_OSERR);

924

}

925

ret = close(devnull);

926

if(ret == -1){

927

perror_plus("close");

928

_exit(EX_OSERR);

929

}

930

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

931

if(ret == -1){

932

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

933

_exit(EX_OSERR);

934

}

935

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

936

O_RDONLY

937

| O_DIRECTORY

938

| O_PATH

939

| O_CLOEXEC));

940

if(helperdir_fd == -1){

941

perror_plus("open");

942

_exit(EX_UNAVAILABLE);

943

}

944

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

945

helper, O_RDONLY));

946

if(helper_fd == -1){

947

perror_plus("openat");

948

close(helperdir_fd);

949

_exit(EX_UNAVAILABLE);

950

}

951

close(helperdir_fd);

952

#ifdef __GNUC__

953

#pragma GCC diagnostic push

954

#pragma GCC diagnostic ignored "-Wcast-qual"

955

#endif

956

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

957

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

958

interface, debug ? debug_flag : NULL, NULL },

959

environ) == -1){

960

#ifdef __GNUC__

961

#pragma GCC diagnostic pop

962

#endif

963

perror_plus("fexecve");

964

_exit(EXIT_FAILURE);

965

}

966

}

967

if(pid == -1){

968

perror_plus("fork");

969

return false;

970

}

971

int status;

972

pid_t pret = -1;

973

errno = 0;

974

do {

975

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

976

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

977

int errno_raising = 0;

978

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

979

errno_raising = errno;

980

perror_plus("Failed to raise privileges in order to"

981

" kill helper program");

982

}

983

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

984

perror_plus("kill");

985

}

986

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

987

perror_plus("Failed to lower privileges after killing"

988

" helper program");

989

}

990

return false;

991

}

992

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

993

if(pret == -1){

994

perror_plus("waitpid");

995

return false;

996

}

997

if(WIFEXITED(status)){

998

if(WEXITSTATUS(status) != 0){

999

fprintf_plus(stderr, "Error: iprouteadddel exited"

1000

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

1001

return false;

1002

}

1003

return true;

1004

}

1005

if(WIFSIGNALED(status)){

1006

fprintf_plus(stderr, "Error: iprouteadddel died by"

1007

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

1008

return false;

1009

}

1010

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

1011

return false;

1012

}

1013

1014

__attribute__((nonnull, warn_unused_result))

1015

static bool add_local_route(const char *address,

1016

AvahiIfIndex if_index){

1017

if(debug){

1018

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

1019

}

1020

return add_delete_local_route(true, address, if_index);

1021

}

1022

1023

__attribute__((nonnull, warn_unused_result))

1024

static bool delete_local_route(const char *address,

1025

AvahiIfIndex if_index){

1026

if(debug){

1027

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

1028

}

1029

return add_delete_local_route(false, address, if_index);

1030

}

1031

643

1032

/* Called when a Mandos server is found */

644

1033

__attribute__((nonnull, warn_unused_result))

645

1034

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

656

1045

int retval = -1;

657

1046

gnutls_session_t session;

658

1047

int pf; /* Protocol family */

1048

bool route_added = false;

659

1049

660

1050

errno = 0;

661

1051

719

1109

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

720

1110

}

721

1111

722

tcp_sd = socket(pf, SOCK_STREAM, 0);

1112

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

723

1113

if(tcp_sd < 0){

724

1114

int e = errno;

725

1115

perror_plus("socket");

732

1122

goto mandos_end;

733

1123

}

734

1124

735

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

736

1125

if(af == AF_INET6){

737

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

738

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

1126

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

1127

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

1128

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

739

1129

} else { /* IPv4 */

740

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

741

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

1130

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

1131

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

1132

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

742

1133

}

743

1134

if(ret < 0 ){

744

1135

int e = errno;

814

1205

goto mandos_end;

815

1206

}

816

1207

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;

1208

while(true){

1209

if(af == AF_INET6){

1210

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

1211

sizeof(struct sockaddr_in6));

1212

} else {

1213

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

1214

sizeof(struct sockaddr_in));

1215

}

1216

if(ret < 0){

1217

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

1218

and if_index != AVAHI_IF_UNSPEC

1219

and connect_to == NULL

1220

and not route_added and

1221

((af == AF_INET6 and not

1222

IN6_IS_ADDR_LINKLOCAL(&(((struct sockaddr_in6 *)

1223

&to)->sin6_addr)))

1224

or (af == AF_INET and

1225

/* Not a a IPv4LL address */

1226

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

1227

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

1228

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

1229

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

1230

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

1231

connect to a Mandos server announced by Avahi on a server

1232

host with a global address. Work around this by retrying

1233

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

1234

1235

Avahi bug reference:

1236

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

1237

https://bugs.debian.org/587961

1238

*/

1239

if(debug){

1240

fprintf_plus(stderr, "Mandos server unreachable, trying"

1241

" direct route\n");

1242

}

1243

int e = errno;

1244

route_added = add_local_route(ip, if_index);

1245

if(route_added){

1246

continue;

1247

}

1248

errno = e;

1249

}

1250

if(errno != ECONNREFUSED or debug){

1251

int e = errno;

1252

perror_plus("connect");

1253

errno = e;

1254

}

1255

goto mandos_end;

1256

}

1257

1258

if(quit_now){

1259

errno = EINTR;

1260

goto mandos_end;

1261

}

1262

break;

836

1263

}

837

1264

838

1265

const char *out = mandos_protocol_version;

1021

1448

1022

1449

mandos_end:

1023

1450

{

1451

if(route_added){

1452

if(not delete_local_route(ip, if_index)){

1453

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

1454

" interface %d", ip, if_index);

1455

}

1456

}

1024

1457

int e = errno;

1025

1458

free(decrypted_buffer);

1026

1459

free(buffer);

1027

1460

if(tcp_sd >= 0){

1028

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

1461

ret = close(tcp_sd);

1029

1462

}

1030

1463

if(ret == -1){

1031

1464

if(e == 0){

1066

1499

timed out */

1067

1500

1068

1501

if(quit_now){

1502

avahi_s_service_resolver_free(r);

1069

1503

return;

1070

1504

}

1071

1505

1194

1628

errno = ret_errno;

1195

1629

return false;

1196

1630

}

1197

strcpy(ifr->ifr_name, ifname);

1631

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

1632

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

1198

1633

ret = ioctl(s, SIOCGIFFLAGS, ifr);

1199

1634

if(ret == -1){

1200

1635

if(debug){

1451

1886

}

1452

1887

}

1453

1888

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

1889

__attribute__((nonnull))

1511

1890

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

1512

1891

const float delay){

1513

struct dirent **direntries;

1892

struct dirent **direntries = NULL;

1514

1893

if(hookdir_fd == -1){

1515

hookdir_fd = open(hookdir, O_RDONLY);

1894

hookdir_fd = open(hookdir, O_RDONLY | O_DIRECTORY | O_PATH

1895

| O_CLOEXEC);

1516

1896

if(hookdir_fd == -1){

1517

1897

if(errno == ENOENT){

1518

1898

if(debug){

1525

1905

return;

1526

1906

}

1527

1907

}

1528

#ifdef __GLIBC__

1529

#if __GLIBC_PREREQ(2, 15)

1530

1908

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

1531

1909

runnable_hook, alphasort);

1532

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

1533

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

1534

alphasort);

1535

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

1536

#else /* not __GLIBC__ */

1537

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

1538

alphasort);

1539

#endif /* not __GLIBC__ */

1540

1910

if(numhooks == -1){

1541

1911

perror_plus("scandir");

1542

1912

return;

1543

1913

}

1544

1914

struct dirent *direntry;

1545

1915

int ret;

1546

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

1916

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

1917

if(devnull == -1){

1918

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

1919

return;

1920

}

1547

1921

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

1548

1922

direntry = direntries[i];

1549

1923

if(debug){

1554

1928

if(hook_pid == 0){

1555

1929

/* Child */

1556

1930

/* Raise privileges */

1557

if(raise_privileges_permanently() != 0){

1931

errno = raise_privileges_permanently();

1932

if(errno != 0){

1558

1933

perror_plus("Failed to raise privileges");

1559

1934

_exit(EX_NOPERM);

1560

1935

}

1572

1947

perror_plus("setgroups");

1573

1948

_exit(EX_NOPERM);

1574

1949

}

1575

ret = dup2(devnull, STDIN_FILENO);

1576

if(ret == -1){

1577

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

1578

_exit(EX_OSERR);

1579

}

1580

ret = close(devnull);

1581

if(ret == -1){

1582

perror_plus("close");

1583

_exit(EX_OSERR);

1584

}

1585

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

1586

if(ret == -1){

1587

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

1588

_exit(EX_OSERR);

1589

}

1590

1950

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

1591

1951

if(ret == -1){

1592

1952

perror_plus("setenv");

1627

1987

_exit(EX_OSERR);

1628

1988

}

1629

1989

}

1630

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

1990

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

1991

direntry->d_name,

1992

O_RDONLY));

1631

1993

if(hook_fd == -1){

1632

1994

perror_plus("openat");

1633

1995

_exit(EXIT_FAILURE);

1634

1996

}

1635

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

1997

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

1636

1998

perror_plus("close");

1637

1999

_exit(EXIT_FAILURE);

1638

2000

}

2001

ret = dup2(devnull, STDIN_FILENO);

2002

if(ret == -1){

2003

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

2004

_exit(EX_OSERR);

2005

}

2006

ret = close(devnull);

2007

if(ret == -1){

2008

perror_plus("close");

2009

_exit(EX_OSERR);

2010

}

2011

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

2012

if(ret == -1){

2013

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

2014

_exit(EX_OSERR);

2015

}

1639

2016

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

1640

2017

environ) == -1){

1641

2018

perror_plus("fexecve");

1642

2019

_exit(EXIT_FAILURE);

1643

2020

}

1644

2021

} else {

2022

if(hook_pid == -1){

2023

perror_plus("fork");

2024

free(direntry);

2025

continue;

2026

}

1645

2027

int status;

1646

2028

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

1647

2029

perror_plus("waitpid");

2030

free(direntry);

1648

2031

continue;

1649

2032

}

1650

2033

if(WIFEXITED(status)){

1652

2035

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

1653

2036

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

1654

2037

WEXITSTATUS(status));

2038

free(direntry);

1655

2039

continue;

1656

2040

}

1657

2041

} else if(WIFSIGNALED(status)){

1658

2042

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

1659

2043

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

1660

2044

WTERMSIG(status));

2045

free(direntry);

1661

2046

continue;

1662

2047

} else {

1663

2048

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

1664

2049

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

2050

free(direntry);

1665

2051

continue;

1666

2052

}

1667

2053

}

1669

2055

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

1670

2056

direntry->d_name);

1671

2057

}

2058

free(direntry);

1672

2059

}

1673

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

2060

free(direntries);

2061

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

1674

2062

perror_plus("close");

1675

2063

} else {

1676

2064

hookdir_fd = -1;

1716

2104

}

1717

2105

1718

2106

if(quit_now){

1719

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

2107

ret = close(sd);

1720

2108

if(ret == -1){

1721

2109

perror_plus("close");

1722

2110

}

1732

2120

/* Raise privileges */

1733

2121

ret_errno = raise_privileges();

1734

2122

if(ret_errno != 0){

2123

errno = ret_errno;

1735

2124

perror_plus("Failed to raise privileges");

1736

2125

}

1737

2126

1771

2160

}

1772

2161

1773

2162

/* Close the socket */

1774

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

2163

ret = close(sd);

1775

2164

if(ret == -1){

1776

2165

perror_plus("close");

1777

2166

}

1841

2230

/* Raise privileges */

1842

2231

ret_errno = raise_privileges();

1843

2232

if(ret_errno != 0){

2233

errno = ret_errno;

1844

2234

perror_plus("Failed to raise privileges");

1845

2235

}

1846

2236

1858

2248

}

1859

2249

1860

2250

/* Close the socket */

1861

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

2251

int ret = close(sd);

1862

2252

if(ret == -1){

1863

2253

perror_plus("close");

1864

2254

}

1879

2269

}

1880

2270

1881

2271

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

1882

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

1883

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

1884

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

1885

.interfaces = NULL, .interfaces_size = 0 };

2272

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

2273

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

2274

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

2275

.current_server = NULL, .interfaces = NULL,

2276

.interfaces_size = 0 };

1886

2277

AvahiSServiceBrowser *sb = NULL;

1887

2278

error_t ret_errno;

1888

2279

int ret;

1897

2288

AvahiIfIndex if_index = AVAHI_IF_UNSPEC;

1898

2289

const char *seckey = PATHDIR "/" SECKEY;

1899

2290

const char *pubkey = PATHDIR "/" PUBKEY;

2291

const char *dh_params_file = NULL;

1900

2292

char *interfaces_hooks = NULL;

1901

2293

1902

2294

bool gnutls_initialized = false;

1955

2347

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

1956

2348

" Diffie-Hellman key exchange",

1957

2349

.group = 2 },

2350

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

2351

.arg = "FILE",

2352

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

2353

" for the Diffie-Hellman key exchange",

2354

.group = 2 },

1958

2355

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

1959

2356

.arg = "STRING",

1960

2357

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

2015

2412

}

2016

2413

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

2017

2414

break;

2415

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

2416

dh_params_file = arg;

2417

break;

2018

2418

case 130: /* --priority */

2019

2419

mc.priority = arg;

2020

2420

break;

2076

2476

goto end;

2077

2477

}

2078

2478

}

2079

2479

2080

2480

{

2081

2481

/* Work around Debian bug #633582:

2082

2482

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

2106

2506

}

2107

2507

}

2108

2508

}

2109

TEMP_FAILURE_RETRY(close(seckey_fd));

2509

close(seckey_fd);

2110

2510

}

2111

2511

}

2112

2512

2113

2513

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

2114

2514

int pubkey_fd = open(pubkey, O_RDONLY);

2115

2515

if(pubkey_fd == -1){

2127

2527

}

2128

2528

}

2129

2529

}

2130

TEMP_FAILURE_RETRY(close(pubkey_fd));

2131

}

2132

}

2133

2530

close(pubkey_fd);

2531

}

2532

}

2533

2534

if(dh_params_file != NULL

2535

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

2536

int dhparams_fd = open(dh_params_file, O_RDONLY);

2537

if(dhparams_fd == -1){

2538

perror_plus("open");

2539

} else {

2540

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

2541

if(ret == -1){

2542

perror_plus("fstat");

2543

} else {

2544

if(S_ISREG(st.st_mode)

2545

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

2546

ret = fchown(dhparams_fd, uid, gid);

2547

if(ret == -1){

2548

perror_plus("fchown");

2549

}

2550

}

2551

}

2552

close(dhparams_fd);

2553

}

2554

}

2555

2134

2556

/* Lower privileges */

2135

2557

ret_errno = lower_privileges();

2136

2558

if(ret_errno != 0){

2265

2687

if(ret_errno != 0){

2266

2688

errno = ret_errno;

2267

2689

perror_plus("argz_add");

2690

free(direntries[i]);

2268

2691

continue;

2269

2692

}

2270

2693

if(debug){

2271

2694

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

2272

2695

direntries[i]->d_name);

2273

2696

}

2697

free(direntries[i]);

2274

2698

}

2275

2699

free(direntries);

2276

2700

} else {

2277

free(direntries);

2701

if(ret == 0){

2702

free(direntries);

2703

}

2278

2704

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

2279

2705

exitcode = EXIT_FAILURE;

2280

2706

goto end;

2306

2732

errno = bring_up_interface(interface, delay);

2307

2733

if(not interface_was_up){

2308

2734

if(errno != 0){

2309

perror_plus("Failed to bring up interface");

2735

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

2736

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

2310

2737

} else {

2311

2738

errno = argz_add(&interfaces_to_take_down,

2312

2739

&interfaces_to_take_down_size,

2335

2762

goto end;

2336

2763

}

2337

2764

2338

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

2765

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

2339

2766

if(ret == -1){

2340

2767

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

2341

2768

exitcode = EX_UNAVAILABLE;

2530

2957

2531

2958

if(gnutls_initialized){

2532

2959

gnutls_certificate_free_credentials(mc.cred);

2533

gnutls_global_deinit();

2534

2960

gnutls_dh_params_deinit(mc.dh_params);

2535

2961

}

2536

2962

2544

2970

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

2545

2971

while(mc.current_server != NULL){

2546

2972

server *next = mc.current_server->next;

2973

#ifdef __GNUC__

2974

#pragma GCC diagnostic push

2975

#pragma GCC diagnostic ignored "-Wcast-qual"

2976

#endif

2977

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

2978

#ifdef __GNUC__

2979

#pragma GCC diagnostic pop

2980

#endif

2547

2981

free(mc.current_server);

2548

2982

mc.current_server = next;

2549

2983

}

2553

2987

{

2554

2988

ret_errno = raise_privileges();

2555

2989

if(ret_errno != 0){

2990

errno = ret_errno;

2556

2991

perror_plus("Failed to raise privileges");

2557

2992

} else {

2558

2993

2581

3016

2582

3017

ret_errno = lower_privileges_permanently();

2583

3018

if(ret_errno != 0){

3019

errno = ret_errno;

2584

3020

perror_plus("Failed to lower privileges permanently");

2585

3021

}

2586

3022

}

2591

3027

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

2592

3028

if(tempdir != NULL){

2593

3029

struct dirent **direntries = NULL;

2594

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

2595

O_NOFOLLOW));

3030

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

3031

| O_NOFOLLOW

3032

| O_DIRECTORY

3033

| O_PATH));

2596

3034

if(tempdir_fd == -1){

2597

3035

perror_plus("open");

2598

3036

} else {

2599

#ifdef __GLIBC__

2600

#if __GLIBC_PREREQ(2, 15)

2601

3037

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

2602

3038

notdotentries, alphasort);

2603

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

2604

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

2605

alphasort);

2606

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

2607

#else /* not __GLIBC__ */

2608

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

2609

alphasort);

2610

#endif /* not __GLIBC__ */

2611

if(numentries > 0){

3039

if(numentries >= 0){

2612

3040

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

2613

3041

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

2614

3042

if(ret == -1){

2616

3044

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

2617

3045

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

2618

3046

}

3047

free(direntries[i]);

2619

3048

}

2620

3049

2621

3050

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

2628

3057

perror_plus("rmdir");

2629

3058

}

2630

3059

}

2631

TEMP_FAILURE_RETRY(close(tempdir_fd));

3060

close(tempdir_fd);

2632

3061

}

2633

3062

}

2634

3063