/mandos/release : revision 237.7.239

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

40

#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), asprintf() */

41

42

#include <stdio.h> /* fprintf(), stderr, fwrite(),

43

stdout, ferror() */

43

stdout, ferror(), remove() */

44

#include <stdint.h> /* uint16_t, uint32_t, intptr_t */

45

#include <stddef.h> /* NULL, size_t, ssize_t */

46

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

47

strtof(), abort() */

48

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

49

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

50

asprintf(), strcpy() */

49

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

50

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

51

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

52

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

53

sockaddr_in6, PF_INET6,

57

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

58

inet_pton(), connect(),

59

getnameinfo() */

60

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

60

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

61

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

62

*/

63

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

73

*/

74

#include <unistd.h> /* close(), SEEK_SET, off_t, write(),

75

getuid(), getgid(), seteuid(),

76

setgid(), pause(), _exit(),

77

unlinkat() */

76

setgid(), pause(), _exit() */

78

77

#include <arpa/inet.h> /* inet_pton(), htons() */

79

78

#include <iso646.h> /* not, or, and */

80

79

#include <argp.h> /* struct argp_option, error_t, struct

234

233

.af = af };

235

234

if(new_server->ip == NULL){

236

235

perror_plus("strdup");

237

free(new_server);

238

236

return false;

239

237

}

240

238

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

241

239

if(ret == -1){

242

240

perror_plus("clock_gettime");

243

#ifdef __GNUC__

244

#pragma GCC diagnostic push

245

#pragma GCC diagnostic ignored "-Wcast-qual"

246

#endif

247

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

248

#ifdef __GNUC__

249

#pragma GCC diagnostic pop

250

#endif

251

free(new_server);

252

241

return false;

253

242

}

254

243

/* Special case of first server */

305

294

return false;

306

295

}

307

296

308

ret = close(fd);

297

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

309

298

if(ret == -1){

310

299

perror_plus("close");

311

300

}

493

482

return plaintext_length;

494

483

}

495

484

496

__attribute__((warn_unused_result, const))

497

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

498

if(str == NULL)

499

return "(unknown)";

500

return str;

501

}

502

503

485

__attribute__((warn_unused_result))

504

486

static const char *safer_gnutls_strerror(int value){

505

487

const char *ret = gnutls_strerror(value);

506

return safe_string(ret);

488

if(ret == NULL)

489

ret = "(unknown)";

490

return ret;

507

491

}

508

492

509

493

/* GnuTLS log function callback */

516

500

__attribute__((nonnull, warn_unused_result))

517

501

static int init_gnutls_global(const char *pubkeyfilename,

518

502

const char *seckeyfilename,

519

const char *dhparamsfilename,

520

503

mandos_context *mc){

521

504

int ret;

522

unsigned int uret;

523

505

524

506

if(debug){

525

507

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

576

558

safer_gnutls_strerror(ret));

577

559

goto globalfail;

578

560

}

579

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

580

if(dhparamsfilename != NULL){

581

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

582

do {

583

int dhpfile = open(dhparamsfilename, O_RDONLY);

584

if(dhpfile == -1){

585

perror_plus("open");

586

dhparamsfilename = NULL;

587

break;

588

}

589

size_t params_capacity = 0;

590

while(true){

591

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

592

(size_t)params.size,

593

(size_t)params_capacity);

594

if(params_capacity == 0){

595

perror_plus("incbuffer");

596

free(params.data);

597

params.data = NULL;

598

dhparamsfilename = NULL;

599

break;

600

}

601

ssize_t bytes_read = read(dhpfile,

602

params.data + params.size,

603

BUFFER_SIZE);

604

/* EOF */

605

if(bytes_read == 0){

606

break;

607

}

608

/* check bytes_read for failure */

609

if(bytes_read < 0){

610

perror_plus("read");

611

free(params.data);

612

params.data = NULL;

613

dhparamsfilename = NULL;

614

break;

615

}

616

params.size += (unsigned int)bytes_read;

617

}

618

if(params.data == NULL){

619

dhparamsfilename = NULL;

620

}

621

if(dhparamsfilename == NULL){

622

break;

623

}

624

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

625

GNUTLS_X509_FMT_PEM);

626

if(ret != GNUTLS_E_SUCCESS){

627

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

628

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

629

safer_gnutls_strerror(ret));

630

dhparamsfilename = NULL;

631

}

632

} while(false);

633

}

634

if(dhparamsfilename == NULL){

635

if(mc->dh_bits == 0){

636

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

637

/* Try to read the private key file */

638

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

639

do {

640

int secfile = open(seckeyfilename, O_RDONLY);

641

if(secfile == -1){

642

perror_plus("open");

643

break;

644

}

645

size_t buffer_capacity = 0;

646

while(true){

647

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

648

(size_t)buffer.size,

649

(size_t)buffer_capacity);

650

if(buffer_capacity == 0){

651

perror_plus("incbuffer");

652

free(buffer.data);

653

buffer.data = NULL;

654

break;

655

}

656

ssize_t bytes_read = read(secfile,

657

buffer.data + buffer.size,

658

BUFFER_SIZE);

659

/* EOF */

660

if(bytes_read == 0){

661

break;

662

}

663

/* check bytes_read for failure */

664

if(bytes_read < 0){

665

perror_plus("read");

666

free(buffer.data);

667

buffer.data = NULL;

668

break;

669

}

670

buffer.size += (unsigned int)bytes_read;

671

}

672

close(secfile);

673

} while(false);

674

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

675

gnutls_sec_param_t sec_param = GNUTLS_SEC_PARAM_ULTRA;

676

if(buffer.data != NULL){

677

{

678

gnutls_openpgp_privkey_t privkey = NULL;

679

ret = gnutls_openpgp_privkey_init(&privkey);

680

if(ret != GNUTLS_E_SUCCESS){

681

fprintf_plus(stderr, "Error initializing OpenPGP key"

682

" structure: %s",

683

safer_gnutls_strerror(ret));

684

free(buffer.data);

685

buffer.data = NULL;

686

} else {

687

ret = gnutls_openpgp_privkey_import

688

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

689

if(ret != GNUTLS_E_SUCCESS){

690

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

691

safer_gnutls_strerror(ret));

692

privkey = NULL;

693

}

694

free(buffer.data);

695

buffer.data = NULL;

696

if(privkey != NULL){

697

/* Use private key to suggest an appropriate

698

sec_param */

699

sec_param = gnutls_openpgp_privkey_sec_param(privkey);

700

gnutls_openpgp_privkey_deinit(privkey);

701

if(debug){

702

fprintf_plus(stderr, "This OpenPGP key implies using"

703

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

704

safe_string(gnutls_sec_param_get_name

705

(sec_param)));

706

}

707

}

708

}

709

}

710

if(sec_param == GNUTLS_SEC_PARAM_UNKNOWN){

711

/* Err on the side of caution */

712

sec_param = GNUTLS_SEC_PARAM_ULTRA;

713

if(debug){

714

fprintf_plus(stderr, "Falling back to security parameter"

715

" \"%s\"\n",

716

safe_string(gnutls_sec_param_get_name

717

(sec_param)));

718

}

719

}

720

}

721

uret = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, sec_param);

722

if(uret != 0){

723

mc->dh_bits = uret;

724

if(debug){

725

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

726

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

727

safe_string(gnutls_sec_param_get_name

728

(sec_param)),

729

mc->dh_bits);

730

}

731

} else {

732

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

733

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

734

safe_string(gnutls_sec_param_get_name

735

(sec_param)),

736

safer_gnutls_strerror(ret));

737

goto globalfail;

738

}

739

} else if(debug){

740

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

741

mc->dh_bits);

742

}

743

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

744

if(ret != GNUTLS_E_SUCCESS){

745

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

746

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

747

safer_gnutls_strerror(ret));

748

goto globalfail;

749

}

750

}

561

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

562

if(ret != GNUTLS_E_SUCCESS){

563

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

564

safer_gnutls_strerror(ret));

565

goto globalfail;

566

}

567

751

568

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

752

569

753

570

return 0;

813

630

/* ignore client certificate if any. */

814

631

gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);

815

632

633

gnutls_dh_set_prime_bits(*session, mc->dh_bits);

634

816

635

return 0;

817

636

}

818

637

820

639

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

821

640

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

822

641

823

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

824

__attribute__((warn_unused_result))

825

error_t raise_privileges(void){

826

error_t old_errno = errno;

827

error_t ret_errno = 0;

828

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

829

ret_errno = errno;

830

}

831

errno = old_errno;

832

return ret_errno;

833

}

834

835

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

836

__attribute__((warn_unused_result))

837

error_t raise_privileges_permanently(void){

838

error_t old_errno = errno;

839

error_t ret_errno = raise_privileges();

840

if(ret_errno != 0){

841

errno = old_errno;

842

return ret_errno;

843

}

844

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

845

ret_errno = errno;

846

}

847

errno = old_errno;

848

return ret_errno;

849

}

850

851

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

852

__attribute__((warn_unused_result))

853

error_t lower_privileges(void){

854

error_t old_errno = errno;

855

error_t ret_errno = 0;

856

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

857

ret_errno = errno;

858

}

859

errno = old_errno;

860

return ret_errno;

861

}

862

863

/* Lower privileges permanently */

864

__attribute__((warn_unused_result))

865

error_t lower_privileges_permanently(void){

866

error_t old_errno = errno;

867

error_t ret_errno = 0;

868

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

869

ret_errno = errno;

870

}

871

errno = old_errno;

872

return ret_errno;

873

}

874

875

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

876

__attribute__((nonnull, warn_unused_result))

877

static bool add_delete_local_route(const bool add,

878

const char *address,

879

AvahiIfIndex if_index){

880

int ret;

881

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

882

char add_arg[] = "add";

883

char delete_arg[] = "delete";

884

char debug_flag[] = "--debug";

885

char *pluginhelperdir = getenv("MANDOSPLUGINHELPERDIR");

886

if(pluginhelperdir == NULL){

887

if(debug){

888

fprintf_plus(stderr, "MANDOSPLUGINHELPERDIR environment"

889

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

890

}

891

return false;

892

}

893

894

char interface[IF_NAMESIZE];

895

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

896

perror_plus("if_indextoname");

897

return false;

898

}

899

900

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

901

if(devnull == -1){

902

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

903

return false;

904

}

905

pid_t pid = fork();

906

if(pid == 0){

907

/* Child */

908

/* Raise privileges */

909

errno = raise_privileges_permanently();

910

if(errno != 0){

911

perror_plus("Failed to raise privileges");

912

/* _exit(EX_NOPERM); */

913

} else {

914

/* Set group */

915

errno = 0;

916

ret = setgid(0);

917

if(ret == -1){

918

perror_plus("setgid");

919

_exit(EX_NOPERM);

920

}

921

/* Reset supplementary groups */

922

errno = 0;

923

ret = setgroups(0, NULL);

924

if(ret == -1){

925

perror_plus("setgroups");

926

_exit(EX_NOPERM);

927

}

928

}

929

ret = dup2(devnull, STDIN_FILENO);

930

if(ret == -1){

931

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

932

_exit(EX_OSERR);

933

}

934

ret = close(devnull);

935

if(ret == -1){

936

perror_plus("close");

937

_exit(EX_OSERR);

938

}

939

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

940

if(ret == -1){

941

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

942

_exit(EX_OSERR);

943

}

944

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

945

O_RDONLY

946

| O_DIRECTORY

947

| O_PATH

948

| O_CLOEXEC));

949

if(helperdir_fd == -1){

950

perror_plus("open");

951

_exit(EX_UNAVAILABLE);

952

}

953

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

954

helper, O_RDONLY));

955

if(helper_fd == -1){

956

perror_plus("openat");

957

close(helperdir_fd);

958

_exit(EX_UNAVAILABLE);

959

}

960

close(helperdir_fd);

961

#ifdef __GNUC__

962

#pragma GCC diagnostic push

963

#pragma GCC diagnostic ignored "-Wcast-qual"

964

#endif

965

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

966

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

967

interface, debug ? debug_flag : NULL, NULL },

968

environ) == -1){

969

#ifdef __GNUC__

970

#pragma GCC diagnostic pop

971

#endif

972

perror_plus("fexecve");

973

_exit(EXIT_FAILURE);

974

}

975

}

976

if(pid == -1){

977

perror_plus("fork");

978

return false;

979

}

980

int status;

981

pid_t pret = -1;

982

errno = 0;

983

do {

984

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

985

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

986

int errno_raising = 0;

987

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

988

errno_raising = errno;

989

perror_plus("Failed to raise privileges in order to"

990

" kill helper program");

991

}

992

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

993

perror_plus("kill");

994

}

995

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

996

perror_plus("Failed to lower privileges after killing"

997

" helper program");

998

}

999

return false;

1000

}

1001

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

1002

if(pret == -1){

1003

perror_plus("waitpid");

1004

return false;

1005

}

1006

if(WIFEXITED(status)){

1007

if(WEXITSTATUS(status) != 0){

1008

fprintf_plus(stderr, "Error: iprouteadddel exited"

1009

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

1010

return false;

1011

}

1012

return true;

1013

}

1014

if(WIFSIGNALED(status)){

1015

fprintf_plus(stderr, "Error: iprouteadddel died by"

1016

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

1017

return false;

1018

}

1019

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

1020

return false;

1021

}

1022

1023

__attribute__((nonnull, warn_unused_result))

1024

static bool add_local_route(const char *address,

1025

AvahiIfIndex if_index){

1026

if(debug){

1027

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

1028

}

1029

return add_delete_local_route(true, address, if_index);

1030

}

1031

1032

__attribute__((nonnull, warn_unused_result))

1033

static bool delete_local_route(const char *address,

1034

AvahiIfIndex if_index){

1035

if(debug){

1036

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

1037

}

1038

return add_delete_local_route(false, address, if_index);

1039

}

1040

1041

642

/* Called when a Mandos server is found */

1042

643

__attribute__((nonnull, warn_unused_result))

1043

644

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

1054

655

int retval = -1;

1055

656

gnutls_session_t session;

1056

657

int pf; /* Protocol family */

1057

bool route_added = false;

1058

658

1059

659

errno = 0;

1060

660

1118

718

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

1119

719

}

1120

720

1121

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

721

tcp_sd = socket(pf, SOCK_STREAM, 0);

1122

722

if(tcp_sd < 0){

1123

723

int e = errno;

1124

724

perror_plus("socket");

1131

731

goto mandos_end;

1132

732

}

1133

733

734

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

1134

735

if(af == AF_INET6){

1135

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

1136

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

1137

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

736

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

737

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

1138

738

} else { /* IPv4 */

1139

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

1140

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

1141

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

739

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

740

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

1142

741

}

1143

742

if(ret < 0 ){

1144

743

int e = errno;

1214

813

goto mandos_end;

1215

814

}

1216

815

1217

while(true){

1218

if(af == AF_INET6){

1219

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

1220

sizeof(struct sockaddr_in6));

1221

} else {

1222

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

1223

sizeof(struct sockaddr_in));

1224

}

1225

if(ret < 0){

1226

if(errno == ENETUNREACH

1227

and if_index != AVAHI_IF_UNSPEC

1228

and connect_to == NULL

1229

and not route_added and

1230

((af == AF_INET6 and not

1231

IN6_IS_ADDR_LINKLOCAL(&(((struct sockaddr_in6 *)

1232

&to)->sin6_addr)))

1233

or (af == AF_INET and

1234

/* Not a a IPv4LL address */

1235

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

1236

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

1237

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

1238

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

1239

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

1240

connect to a Mandos server announced by Avahi on a server

1241

host with a global address. Work around this by retrying

1242

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

1243

1244

Avahi bug reference:

1245

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

1246

https://bugs.debian.org/587961

1247

*/

1248

if(debug){

1249

fprintf_plus(stderr, "Mandos server unreachable, trying"

1250

" direct route\n");

1251

}

1252

int e = errno;

1253

route_added = add_local_route(ip, if_index);

1254

if(route_added){

1255

continue;

1256

}

1257

errno = e;

1258

}

1259

if(errno != ECONNREFUSED or debug){

1260

int e = errno;

1261

perror_plus("connect");

1262

errno = e;

1263

}

1264

goto mandos_end;

1265

}

1266

1267

if(quit_now){

1268

errno = EINTR;

1269

goto mandos_end;

1270

}

1271

break;

816

if(af == AF_INET6){

817

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

818

sizeof(struct sockaddr_in6));

819

} else {

820

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

821

sizeof(struct sockaddr_in));

822

}

823

if(ret < 0){

824

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

825

int e = errno;

826

perror_plus("connect");

827

errno = e;

828

}

829

goto mandos_end;

830

}

831

832

if(quit_now){

833

errno = EINTR;

834

goto mandos_end;

1272

835

}

1273

836

1274

837

const char *out = mandos_protocol_version;

1457

1020

1458

1021

mandos_end:

1459

1022

{

1460

if(route_added){

1461

if(not delete_local_route(ip, if_index)){

1462

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

1463

" interface %d", ip, if_index);

1464

}

1465

}

1466

1023

int e = errno;

1467

1024

free(decrypted_buffer);

1468

1025

free(buffer);

1469

1026

if(tcp_sd >= 0){

1470

ret = close(tcp_sd);

1027

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

1471

1028

}

1472

1029

if(ret == -1){

1473

1030

if(e == 0){

1508

1065

timed out */

1509

1066

1510

1067

if(quit_now){

1511

avahi_s_service_resolver_free(r);

1512

1068

return;

1513

1069

}

1514

1070

1790

1346

return 0;

1791

1347

}

1792

1348

1793

ret = fstatat(hookdir_fd, direntry->d_name, &st, 0);

1349

char *fullname = NULL;

1350

ret = asprintf(&fullname, "%s/%s", hookdir, direntry->d_name);

1351

if(ret < 0){

1352

perror_plus("asprintf");

1353

return 0;

1354

}

1355

1356

ret = stat(fullname, &st);

1794

1357

if(ret == -1){

1795

1358

if(debug){

1796

1359

perror_plus("Could not stat hook");

1797

1360

}

1798

1361

return 0;

1799

1362

}

1363

free(fullname);

1800

1364

if(not (S_ISREG(st.st_mode))){

1801

1365

/* Not a regular file */

1802

1366

if(debug){

1894

1458

}

1895

1459

}

1896

1460

1461

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

1462

__attribute__((warn_unused_result))

1463

error_t raise_privileges(void){

1464

error_t old_errno = errno;

1465

error_t ret_errno = 0;

1466

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

1467

ret_errno = errno;

1468

perror_plus("seteuid");

1469

}

1470

errno = old_errno;

1471

return ret_errno;

1472

}

1473

1474

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

1475

__attribute__((warn_unused_result))

1476

error_t raise_privileges_permanently(void){

1477

error_t old_errno = errno;

1478

error_t ret_errno = raise_privileges();

1479

if(ret_errno != 0){

1480

errno = old_errno;

1481

return ret_errno;

1482

}

1483

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

1484

ret_errno = errno;

1485

perror_plus("seteuid");

1486

}

1487

errno = old_errno;

1488

return ret_errno;

1489

}

1490

1491

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

1492

__attribute__((warn_unused_result))

1493

error_t lower_privileges(void){

1494

error_t old_errno = errno;

1495

error_t ret_errno = 0;

1496

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

1497

ret_errno = errno;

1498

perror_plus("seteuid");

1499

}

1500

errno = old_errno;

1501

return ret_errno;

1502

}

1503

1504

/* Lower privileges permanently */

1505

__attribute__((warn_unused_result))

1506

error_t lower_privileges_permanently(void){

1507

error_t old_errno = errno;

1508

error_t ret_errno = 0;

1509

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

1510

ret_errno = errno;

1511

perror_plus("setuid");

1512

}

1513

errno = old_errno;

1514

return ret_errno;

1515

}

1516

1517

#ifndef O_CLOEXEC

1518

/*

1519

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

1520

* Descriptor Flags".

1521

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

1522

*/

1523

__attribute__((warn_unused_result))

1524

static int set_cloexec_flag(int fd){

1525

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

1526

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

1527

if(ret < 0){

1528

return ret;

1529

}

1530

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

1531

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

1532

ret | FD_CLOEXEC));

1533

}

1534

#endif /* not O_CLOEXEC */

1535

1897

1536

__attribute__((nonnull))

1898

1537

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

1899

1538

const float delay){

1900

struct dirent **direntries = NULL;

1539

struct dirent **direntries;

1901

1540

if(hookdir_fd == -1){

1902

hookdir_fd = open(hookdir, O_RDONLY | O_DIRECTORY | O_PATH

1903

| O_CLOEXEC);

1541

hookdir_fd = open(hookdir, O_RDONLY |

1542

#ifdef O_CLOEXEC

1543

O_CLOEXEC

1544

#else /* not O_CLOEXEC */

1545

0

1546

#endif /* not O_CLOEXEC */

1547

);

1904

1548

if(hookdir_fd == -1){

1905

1549

if(errno == ENOENT){

1906

1550

if(debug){

1912

1556

}

1913

1557

return;

1914

1558

}

1559

#ifndef O_CLOEXEC

1560

if(set_cloexec_flag(hookdir_fd) < 0){

1561

perror_plus("set_cloexec_flag");

1562

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

1563

perror_plus("close");

1564

} else {

1565

hookdir_fd = -1;

1566

}

1567

return;

1568

}

1569

#endif /* not O_CLOEXEC */

1915

1570

}

1916

1571

#ifdef __GLIBC__

1917

1572

#if __GLIBC_PREREQ(2, 15)

1931

1586

}

1932

1587

struct dirent *direntry;

1933

1588

int ret;

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

}

1589

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

1939

1590

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

1940

1591

direntry = direntries[i];

1592

char *fullname = NULL;

1593

ret = asprintf(&fullname, "%s/%s", hookdir, direntry->d_name);

1594

if(ret < 0){

1595

perror_plus("asprintf");

1596

continue;

1597

}

1941

1598

if(debug){

1942

1599

fprintf_plus(stderr, "Running network hook \"%s\"\n",

1943

1600

direntry->d_name);

1946

1603

if(hook_pid == 0){

1947

1604

/* Child */

1948

1605

/* Raise privileges */

1949

errno = raise_privileges_permanently();

1950

if(errno != 0){

1606

if(raise_privileges_permanently() != 0){

1951

1607

perror_plus("Failed to raise privileges");

1952

1608

_exit(EX_NOPERM);

1953

1609

}

1965

1621

perror_plus("setgroups");

1966

1622

_exit(EX_NOPERM);

1967

1623

}

1624

ret = dup2(devnull, STDIN_FILENO);

1625

if(ret == -1){

1626

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

1627

_exit(EX_OSERR);

1628

}

1629

ret = close(devnull);

1630

if(ret == -1){

1631

perror_plus("close");

1632

_exit(EX_OSERR);

1633

}

1634

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

1635

if(ret == -1){

1636

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

1637

_exit(EX_OSERR);

1638

}

1968

1639

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

1969

1640

if(ret == -1){

1970

1641

perror_plus("setenv");

2005

1676

_exit(EX_OSERR);

2006

1677

}

2007

1678

}

2008

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

2009

direntry->d_name,

2010

O_RDONLY));

2011

if(hook_fd == -1){

2012

perror_plus("openat");

2013

_exit(EXIT_FAILURE);

2014

}

2015

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

2016

perror_plus("close");

2017

_exit(EXIT_FAILURE);

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

}

2034

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

2035

environ) == -1){

2036

perror_plus("fexecve");

1679

if(execl(fullname, direntry->d_name, mode, NULL) == -1){

1680

perror_plus("execl");

2037

1681

_exit(EXIT_FAILURE);

2038

1682

}

2039

1683

} else {

2040

if(hook_pid == -1){

2041

perror_plus("fork");

2042

free(direntry);

2043

continue;

2044

}

2045

1684

int status;

2046

1685

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

2047

1686

perror_plus("waitpid");

2048

free(direntry);

1687

free(fullname);

2049

1688

continue;

2050

1689

}

2051

1690

if(WIFEXITED(status)){

2053

1692

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

2054

1693

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

2055

1694

WEXITSTATUS(status));

2056

free(direntry);

1695

free(fullname);

2057

1696

continue;

2058

1697

}

2059

1698

} else if(WIFSIGNALED(status)){

2060

1699

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

2061

1700

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

2062

1701

WTERMSIG(status));

2063

free(direntry);

1702

free(fullname);

2064

1703

continue;

2065

1704

} else {

2066

1705

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

2067

1706

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

2068

free(direntry);

1707

free(fullname);

2069

1708

continue;

2070

1709

}

2071

1710

}

1711

free(fullname);

2072

1712

if(debug){

2073

1713

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

2074

1714

direntry->d_name);

2075

1715

}

2076

free(direntry);

2077

1716

}

2078

free(direntries);

2079

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

1717

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

2080

1718

perror_plus("close");

2081

1719

} else {

2082

1720

hookdir_fd = -1;

2122

1760

}

2123

1761

2124

1762

if(quit_now){

2125

ret = close(sd);

1763

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

2126

1764

if(ret == -1){

2127

1765

perror_plus("close");

2128

1766

}

2138

1776

/* Raise privileges */

2139

1777

ret_errno = raise_privileges();

2140

1778

if(ret_errno != 0){

2141

errno = ret_errno;

2142

1779

perror_plus("Failed to raise privileges");

2143

1780

}

2144

1781

2178

1815

}

2179

1816

2180

1817

/* Close the socket */

2181

ret = close(sd);

1818

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

2182

1819

if(ret == -1){

2183

1820

perror_plus("close");

2184

1821

}

2248

1885

/* Raise privileges */

2249

1886

ret_errno = raise_privileges();

2250

1887

if(ret_errno != 0){

2251

errno = ret_errno;

2252

1888

perror_plus("Failed to raise privileges");

2253

1889

}

2254

1890

2266

1902

}

2267

1903

2268

1904

/* Close the socket */

2269

int ret = close(sd);

1905

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

2270

1906

if(ret == -1){

2271

1907

perror_plus("close");

2272

1908

}

2287

1923

}

2288

1924

2289

1925

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

2290

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

2291

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

2292

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

2293

.current_server = NULL, .interfaces = NULL,

2294

.interfaces_size = 0 };

1926

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

1927

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

1928

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

1929

.interfaces = NULL, .interfaces_size = 0 };

2295

1930

AvahiSServiceBrowser *sb = NULL;

2296

1931

error_t ret_errno;

2297

1932

int ret;

2306

1941

AvahiIfIndex if_index = AVAHI_IF_UNSPEC;

2307

1942

const char *seckey = PATHDIR "/" SECKEY;

2308

1943

const char *pubkey = PATHDIR "/" PUBKEY;

2309

const char *dh_params_file = NULL;

2310

1944

char *interfaces_hooks = NULL;

2311

1945

2312

1946

bool gnutls_initialized = false;

2365

1999

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

2366

2000

" Diffie-Hellman key exchange",

2367

2001

.group = 2 },

2368

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

2369

.arg = "FILE",

2370

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

2371

" for the Diffie-Hellman key exchange",

2372

.group = 2 },

2373

2002

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

2374

2003

.arg = "STRING",

2375

2004

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

2430

2059

}

2431

2060

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

2432

2061

break;

2433

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

2434

dh_params_file = arg;

2435

break;

2436

2062

case 130: /* --priority */

2437

2063

mc.priority = arg;

2438

2064

break;

2494

2120

goto end;

2495

2121

}

2496

2122

}

2497

2123

2498

2124

{

2499

2125

/* Work around Debian bug #633582:

2500

2126

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

2524

2150

}

2525

2151

}

2526

2152

}

2527

close(seckey_fd);

2153

TEMP_FAILURE_RETRY(close(seckey_fd));

2528

2154

}

2529

2155

}

2530

2156

2531

2157

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

2532

2158

int pubkey_fd = open(pubkey, O_RDONLY);

2533

2159

if(pubkey_fd == -1){

2545

2171

}

2546

2172

}

2547

2173

}

2548

close(pubkey_fd);

2549

}

2550

}

2551

2552

if(dh_params_file != NULL

2553

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

2554

int dhparams_fd = open(dh_params_file, O_RDONLY);

2555

if(dhparams_fd == -1){

2556

perror_plus("open");

2557

} else {

2558

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

2559

if(ret == -1){

2560

perror_plus("fstat");

2561

} else {

2562

if(S_ISREG(st.st_mode)

2563

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

2564

ret = fchown(dhparams_fd, uid, gid);

2565

if(ret == -1){

2566

perror_plus("fchown");

2567

}

2568

}

2569

}

2570

close(dhparams_fd);

2571

}

2572

}

2573

2174

TEMP_FAILURE_RETRY(close(pubkey_fd));

2175

}

2176

}

2177

2574

2178

/* Lower privileges */

2575

2179

ret_errno = lower_privileges();

2576

2180

if(ret_errno != 0){

2693

2297

2694

2298

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

2695

2299

if(mc.interfaces == NULL){

2696

struct dirent **direntries = NULL;

2300

struct dirent **direntries;

2697

2301

/* Look for any good interfaces */

2698

2302

ret = scandir(sys_class_net, &direntries, good_interface,

2699

2303

alphasort);

2705

2309

if(ret_errno != 0){

2706

2310

errno = ret_errno;

2707

2311

perror_plus("argz_add");

2708

free(direntries[i]);

2709

2312

continue;

2710

2313

}

2711

2314

if(debug){

2712

2315

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

2713

2316

direntries[i]->d_name);

2714

2317

}

2715

free(direntries[i]);

2716

2318

}

2717

2319

free(direntries);

2718

2320

} else {

2719

if(ret == 0){

2720

free(direntries);

2721

}

2321

free(direntries);

2722

2322

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

2723

2323

exitcode = EXIT_FAILURE;

2724

2324

goto end;

2750

2350

errno = bring_up_interface(interface, delay);

2751

2351

if(not interface_was_up){

2752

2352

if(errno != 0){

2753

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

2754

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

2353

perror_plus("Failed to bring up interface");

2755

2354

} else {

2756

2355

errno = argz_add(&interfaces_to_take_down,

2757

2356

&interfaces_to_take_down_size,

2780

2379

goto end;

2781

2380

}

2782

2381

2783

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

2382

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

2784

2383

if(ret == -1){

2785

2384

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

2786

2385

exitcode = EX_UNAVAILABLE;

2989

2588

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

2990

2589

while(mc.current_server != NULL){

2991

2590

server *next = mc.current_server->next;

2992

#ifdef __GNUC__

2993

#pragma GCC diagnostic push

2994

#pragma GCC diagnostic ignored "-Wcast-qual"

2995

#endif

2996

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

2997

#ifdef __GNUC__

2998

#pragma GCC diagnostic pop

2999

#endif

3000

2591

free(mc.current_server);

3001

2592

mc.current_server = next;

3002

2593

}

3006

2597

{

3007

2598

ret_errno = raise_privileges();

3008

2599

if(ret_errno != 0){

3009

errno = ret_errno;

3010

2600

perror_plus("Failed to raise privileges");

3011

2601

} else {

3012

2602

3035

2625

3036

2626

ret_errno = lower_privileges_permanently();

3037

2627

if(ret_errno != 0){

3038

errno = ret_errno;

3039

2628

perror_plus("Failed to lower privileges permanently");

3040

2629

}

3041

2630

}

3046

2635

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

3047

2636

if(tempdir != NULL){

3048

2637

struct dirent **direntries = NULL;

3049

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

3050

| O_NOFOLLOW

3051

| O_DIRECTORY

3052

| O_PATH));

3053

if(tempdir_fd == -1){

3054

perror_plus("open");

3055

} else {

3056

#ifdef __GLIBC__

3057

#if __GLIBC_PREREQ(2, 15)

3058

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

3059

notdotentries, alphasort);

3060

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

3061

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

3062

alphasort);

3063

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

3064

#else /* not __GLIBC__ */

3065

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

3066

alphasort);

3067

#endif /* not __GLIBC__ */

3068

if(numentries >= 0){

3069

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

3070

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

3071

if(ret == -1){

3072

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

3073

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

3074

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

3075

}

3076

free(direntries[i]);

3077

}

3078

3079

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

3080

free(direntries);

3081

if(numentries == -1){

3082

perror_plus("scandir");

3083

}

3084

ret = rmdir(tempdir);

3085

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

3086

perror_plus("rmdir");

3087

}

2638

struct dirent *direntry = NULL;

2639

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

2640

alphasort);

2641

if(numentries > 0){

2642

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

2643

direntry = direntries[i];

2644

char *fullname = NULL;

2645

ret = asprintf(&fullname, "%s/%s", tempdir,

2646

direntry->d_name);

2647

if(ret < 0){

2648

perror_plus("asprintf");

2649

continue;

2650

}

2651

ret = remove(fullname);

2652

if(ret == -1){

2653

fprintf_plus(stderr, "remove(\"%s\"): %s\n", fullname,

2654

strerror(errno));

2655

}

2656

free(fullname);

3088

2657

}

3089

close(tempdir_fd);

2658

}

2659

2660

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

2661

free(direntries);

2662

if(numentries == -1){

2663

perror_plus("scandir");

2664

}

2665

ret = rmdir(tempdir);

2666

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

2667

perror_plus("rmdir");

3090

2668

}

3091

2669

}

3092

2670