/mandos/trunk : revision 810

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(), remove() */

43

stdout, ferror() */

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> /* 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,

57

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

58

inet_pton(), connect(),

59

getnameinfo() */

60

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

60

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

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() */

76

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

77

unlinkat() */

77

78

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

78

79

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

79

80

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

233

234

.af = af };

234

235

if(new_server->ip == NULL){

235

236

perror_plus("strdup");

237

free(new_server);

236

238

return false;

237

239

}

238

240

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

239

241

if(ret == -1){

240

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);

241

252

return false;

242

253

}

243

254

/* Special case of first server */

294

305

return false;

295

306

}

296

307

297

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

308

ret = close(fd);

298

309

if(ret == -1){

299

310

perror_plus("close");

300

311

}

482

493

return plaintext_length;

483

494

}

484

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

485

503

__attribute__((warn_unused_result))

486

504

static const char *safer_gnutls_strerror(int value){

487

505

const char *ret = gnutls_strerror(value);

488

if(ret == NULL)

489

ret = "(unknown)";

490

return ret;

506

return safe_string(ret);

491

507

}

492

508

493

509

/* GnuTLS log function callback */

500

516

__attribute__((nonnull, warn_unused_result))

501

517

static int init_gnutls_global(const char *pubkeyfilename,

502

518

const char *seckeyfilename,

519

const char *dhparamsfilename,

503

520

mandos_context *mc){

504

521

int ret;

522

unsigned int uret;

505

523

506

524

if(debug){

507

525

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

558

576

safer_gnutls_strerror(ret));

559

577

goto globalfail;

560

578

}

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

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

}

568

751

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

569

752

570

753

return 0;

630

813

/* ignore client certificate if any. */

631

814

gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);

632

815

633

gnutls_dh_set_prime_bits(*session, mc->dh_bits);

634

635

816

return 0;

636

817

}

637

818

639

820

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

640

821

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

641

822

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

642

1041

/* Called when a Mandos server is found */

643

1042

__attribute__((nonnull, warn_unused_result))

644

1043

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

655

1054

int retval = -1;

656

1055

gnutls_session_t session;

657

1056

int pf; /* Protocol family */

1057

bool route_added = false;

658

1058

659

1059

errno = 0;

660

1060

718

1118

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

719

1119

}

720

1120

721

tcp_sd = socket(pf, SOCK_STREAM, 0);

1121

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

722

1122

if(tcp_sd < 0){

723

1123

int e = errno;

724

1124

perror_plus("socket");

731

1131

goto mandos_end;

732

1132

}

733

1133

734

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

735

1134

if(af == AF_INET6){

736

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

737

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

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);

738

1138

} else { /* IPv4 */

739

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

740

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

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);

741

1142

}

742

1143

if(ret < 0 ){

743

1144

int e = errno;

813

1214

goto mandos_end;

814

1215

}

815

1216

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;

1217

while(true){

1218

if(af == AF_INET6){

1219

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

1220

sizeof(struct sockaddr_in6));

1221

} else {

1222

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

1223

sizeof(struct sockaddr_in));

1224

}

1225

if(ret < 0){

1226

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

1227

and if_index != AVAHI_IF_UNSPEC

1228

and connect_to == NULL

1229

and not route_added and

1230

((af == AF_INET6 and not

1231

IN6_IS_ADDR_LINKLOCAL(&(((struct sockaddr_in6 *)

1232

&to)->sin6_addr)))

1233

or (af == AF_INET and

1234

/* Not a a IPv4LL address */

1235

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

1236

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

1237

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

1238

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

1239

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

1240

connect to a Mandos server announced by Avahi on a server

1241

host with a global address. Work around this by retrying

1242

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

1243

1244

Avahi bug reference:

1245

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

1246

https://bugs.debian.org/587961

1247

*/

1248

if(debug){

1249

fprintf_plus(stderr, "Mandos server unreachable, trying"

1250

" direct route\n");

1251

}

1252

int e = errno;

1253

route_added = add_local_route(ip, if_index);

1254

if(route_added){

1255

continue;

1256

}

1257

errno = e;

1258

}

1259

if(errno != ECONNREFUSED or debug){

1260

int e = errno;

1261

perror_plus("connect");

1262

errno = e;

1263

}

1264

goto mandos_end;

1265

}

1266

1267

if(quit_now){

1268

errno = EINTR;

1269

goto mandos_end;

1270

}

1271

break;

835

1272

}

836

1273

837

1274

const char *out = mandos_protocol_version;

1020

1457

1021

1458

mandos_end:

1022

1459

{

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

}

1023

1466

int e = errno;

1024

1467

free(decrypted_buffer);

1025

1468

free(buffer);

1026

1469

if(tcp_sd >= 0){

1027

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

1470

ret = close(tcp_sd);

1028

1471

}

1029

1472

if(ret == -1){

1030

1473

if(e == 0){

1065

1508

timed out */

1066

1509

1067

1510

if(quit_now){

1511

avahi_s_service_resolver_free(r);

1068

1512

return;

1069

1513

}

1070

1514

1193

1637

errno = ret_errno;

1194

1638

return false;

1195

1639

}

1196

strcpy(ifr->ifr_name, ifname);

1640

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

1641

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

1197

1642

ret = ioctl(s, SIOCGIFFLAGS, ifr);

1198

1643

if(ret == -1){

1199

1644

if(debug){

1450

1895

}

1451

1896

}

1452

1897

1453

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

1454

__attribute__((warn_unused_result))

1455

error_t raise_privileges(void){

1456

error_t old_errno = errno;

1457

error_t ret_errno = 0;

1458

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

1459

ret_errno = errno;

1460

perror_plus("seteuid");

1461

}

1462

errno = old_errno;

1463

return ret_errno;

1464

}

1465

1466

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

1467

__attribute__((warn_unused_result))

1468

error_t raise_privileges_permanently(void){

1469

error_t old_errno = errno;

1470

error_t ret_errno = raise_privileges();

1471

if(ret_errno != 0){

1472

errno = old_errno;

1473

return ret_errno;

1474

}

1475

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

1476

ret_errno = errno;

1477

perror_plus("seteuid");

1478

}

1479

errno = old_errno;

1480

return ret_errno;

1481

}

1482

1483

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

1484

__attribute__((warn_unused_result))

1485

error_t lower_privileges(void){

1486

error_t old_errno = errno;

1487

error_t ret_errno = 0;

1488

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

1489

ret_errno = errno;

1490

perror_plus("seteuid");

1491

}

1492

errno = old_errno;

1493

return ret_errno;

1494

}

1495

1496

/* Lower privileges permanently */

1497

__attribute__((warn_unused_result))

1498

error_t lower_privileges_permanently(void){

1499

error_t old_errno = errno;

1500

error_t ret_errno = 0;

1501

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

1502

ret_errno = errno;

1503

perror_plus("setuid");

1504

}

1505

errno = old_errno;

1506

return ret_errno;

1507

}

1508

1509

#ifndef O_CLOEXEC

1510

/*

1511

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

1512

* Descriptor Flags".

1513

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

1514

*/

1515

__attribute__((warn_unused_result))

1516

static int set_cloexec_flag(int fd){

1517

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

1518

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

1519

if(ret < 0){

1520

return ret;

1521

}

1522

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

1523

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

1524

ret | FD_CLOEXEC));

1525

}

1526

#endif /* not O_CLOEXEC */

1527

1528

1898

__attribute__((nonnull))

1529

1899

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

1530

1900

const float delay){

1531

struct dirent **direntries;

1901

struct dirent **direntries = NULL;

1532

1902

if(hookdir_fd == -1){

1533

hookdir_fd = open(hookdir, O_RDONLY |

1534

#ifdef O_CLOEXEC

1535

O_CLOEXEC

1536

#else /* not O_CLOEXEC */

1537

0

1538

#endif /* not O_CLOEXEC */

1539

);

1903

hookdir_fd = open(hookdir, O_RDONLY | O_DIRECTORY | O_PATH

1904

| O_CLOEXEC);

1540

1905

if(hookdir_fd == -1){

1541

1906

if(errno == ENOENT){

1542

1907

if(debug){

1548

1913

}

1549

1914

return;

1550

1915

}

1551

#ifndef O_CLOEXEC

1552

if(set_cloexec_flag(hookdir_fd) < 0){

1553

perror_plus("set_cloexec_flag");

1554

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

1555

perror_plus("close");

1556

} else {

1557

hookdir_fd = -1;

1558

}

1559

return;

1560

}

1561

#endif /* not O_CLOEXEC */

1562

1916

}

1563

#ifdef __GLIBC__

1564

#if __GLIBC_PREREQ(2, 15)

1565

1917

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

1566

1918

runnable_hook, alphasort);

1567

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

1568

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

1569

alphasort);

1570

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

1571

#else /* not __GLIBC__ */

1572

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

1573

alphasort);

1574

#endif /* not __GLIBC__ */

1575

1919

if(numhooks == -1){

1576

1920

perror_plus("scandir");

1577

1921

return;

1578

1922

}

1579

1923

struct dirent *direntry;

1580

1924

int ret;

1581

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

1925

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

1926

if(devnull == -1){

1927

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

1928

return;

1929

}

1582

1930

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

1583

1931

direntry = direntries[i];

1584

1932

if(debug){

1589

1937

if(hook_pid == 0){

1590

1938

/* Child */

1591

1939

/* Raise privileges */

1592

if(raise_privileges_permanently() != 0){

1940

errno = raise_privileges_permanently();

1941

if(errno != 0){

1593

1942

perror_plus("Failed to raise privileges");

1594

1943

_exit(EX_NOPERM);

1595

1944

}

1607

1956

perror_plus("setgroups");

1608

1957

_exit(EX_NOPERM);

1609

1958

}

1610

ret = dup2(devnull, STDIN_FILENO);

1611

if(ret == -1){

1612

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

1613

_exit(EX_OSERR);

1614

}

1615

ret = close(devnull);

1616

if(ret == -1){

1617

perror_plus("close");

1618

_exit(EX_OSERR);

1619

}

1620

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

1621

if(ret == -1){

1622

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

1623

_exit(EX_OSERR);

1624

}

1625

1959

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

1626

1960

if(ret == -1){

1627

1961

perror_plus("setenv");

1662

1996

_exit(EX_OSERR);

1663

1997

}

1664

1998

}

1665

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

1666

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

1999

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

2000

direntry->d_name,

2001

O_RDONLY));

2002

if(hook_fd == -1){

2003

perror_plus("openat");

2004

_exit(EXIT_FAILURE);

2005

}

2006

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

2007

perror_plus("close");

2008

_exit(EXIT_FAILURE);

2009

}

2010

ret = dup2(devnull, STDIN_FILENO);

2011

if(ret == -1){

2012

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

2013

_exit(EX_OSERR);

2014

}

2015

ret = close(devnull);

2016

if(ret == -1){

2017

perror_plus("close");

2018

_exit(EX_OSERR);

2019

}

2020

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

2021

if(ret == -1){

2022

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

2023

_exit(EX_OSERR);

2024

}

2025

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

2026

environ) == -1){

1667

2027

perror_plus("fexecve");

1668

2028

_exit(EXIT_FAILURE);

1669

2029

}

1670

2030

} else {

2031

if(hook_pid == -1){

2032

perror_plus("fork");

2033

free(direntry);

2034

continue;

2035

}

1671

2036

int status;

1672

2037

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

1673

2038

perror_plus("waitpid");

2039

free(direntry);

1674

2040

continue;

1675

2041

}

1676

2042

if(WIFEXITED(status)){

1678

2044

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

1679

2045

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

1680

2046

WEXITSTATUS(status));

2047

free(direntry);

1681

2048

continue;

1682

2049

}

1683

2050

} else if(WIFSIGNALED(status)){

1684

2051

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

1685

2052

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

1686

2053

WTERMSIG(status));

2054

free(direntry);

1687

2055

continue;

1688

2056

} else {

1689

2057

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

1690

2058

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

2059

free(direntry);

1691

2060

continue;

1692

2061

}

1693

2062

}

1695

2064

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

1696

2065

direntry->d_name);

1697

2066

}

2067

free(direntry);

1698

2068

}

1699

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

2069

free(direntries);

2070

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

1700

2071

perror_plus("close");

1701

2072

} else {

1702

2073

hookdir_fd = -1;

1742

2113

}

1743

2114

1744

2115

if(quit_now){

1745

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

2116

ret = close(sd);

1746

2117

if(ret == -1){

1747

2118

perror_plus("close");

1748

2119

}

1758

2129

/* Raise privileges */

1759

2130

ret_errno = raise_privileges();

1760

2131

if(ret_errno != 0){

2132

errno = ret_errno;

1761

2133

perror_plus("Failed to raise privileges");

1762

2134

}

1763

2135

1797

2169

}

1798

2170

1799

2171

/* Close the socket */

1800

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

2172

ret = close(sd);

1801

2173

if(ret == -1){

1802

2174

perror_plus("close");

1803

2175

}

1867

2239

/* Raise privileges */

1868

2240

ret_errno = raise_privileges();

1869

2241

if(ret_errno != 0){

2242

errno = ret_errno;

1870

2243

perror_plus("Failed to raise privileges");

1871

2244

}

1872

2245

1884

2257

}

1885

2258

1886

2259

/* Close the socket */

1887

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

2260

int ret = close(sd);

1888

2261

if(ret == -1){

1889

2262

perror_plus("close");

1890

2263

}

1905

2278

}

1906

2279

1907

2280

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

1908

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

1909

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

1910

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

1911

.interfaces = NULL, .interfaces_size = 0 };

2281

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

2282

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

2283

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

2284

.current_server = NULL, .interfaces = NULL,

2285

.interfaces_size = 0 };

1912

2286

AvahiSServiceBrowser *sb = NULL;

1913

2287

error_t ret_errno;

1914

2288

int ret;

1923

2297

AvahiIfIndex if_index = AVAHI_IF_UNSPEC;

1924

2298

const char *seckey = PATHDIR "/" SECKEY;

1925

2299

const char *pubkey = PATHDIR "/" PUBKEY;

2300

const char *dh_params_file = NULL;

1926

2301

char *interfaces_hooks = NULL;

1927

2302

1928

2303

bool gnutls_initialized = false;

1981

2356

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

1982

2357

" Diffie-Hellman key exchange",

1983

2358

.group = 2 },

2359

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

2360

.arg = "FILE",

2361

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

2362

" for the Diffie-Hellman key exchange",

2363

.group = 2 },

1984

2364

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

1985

2365

.arg = "STRING",

1986

2366

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

2041

2421

}

2042

2422

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

2043

2423

break;

2424

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

2425

dh_params_file = arg;

2426

break;

2044

2427

case 130: /* --priority */

2045

2428

mc.priority = arg;

2046

2429

break;

2102

2485

goto end;

2103

2486

}

2104

2487

}

2105

2488

2106

2489

{

2107

2490

/* Work around Debian bug #633582:

2108

2491

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

2132

2515

}

2133

2516

}

2134

2517

}

2135

TEMP_FAILURE_RETRY(close(seckey_fd));

2518

close(seckey_fd);

2136

2519

}

2137

2520

}

2138

2521

2139

2522

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

2140

2523

int pubkey_fd = open(pubkey, O_RDONLY);

2141

2524

if(pubkey_fd == -1){

2153

2536

}

2154

2537

}

2155

2538

}

2156

TEMP_FAILURE_RETRY(close(pubkey_fd));

2157

}

2158

}

2159

2539

close(pubkey_fd);

2540

}

2541

}

2542

2543

if(dh_params_file != NULL

2544

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

2545

int dhparams_fd = open(dh_params_file, O_RDONLY);

2546

if(dhparams_fd == -1){

2547

perror_plus("open");

2548

} else {

2549

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

2550

if(ret == -1){

2551

perror_plus("fstat");

2552

} else {

2553

if(S_ISREG(st.st_mode)

2554

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

2555

ret = fchown(dhparams_fd, uid, gid);

2556

if(ret == -1){

2557

perror_plus("fchown");

2558

}

2559

}

2560

}

2561

close(dhparams_fd);

2562

}

2563

}

2564

2160

2565

/* Lower privileges */

2161

2566

ret_errno = lower_privileges();

2162

2567

if(ret_errno != 0){

2279

2684

2280

2685

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

2281

2686

if(mc.interfaces == NULL){

2282

struct dirent **direntries;

2687

struct dirent **direntries = NULL;

2283

2688

/* Look for any good interfaces */

2284

2689

ret = scandir(sys_class_net, &direntries, good_interface,

2285

2690

alphasort);

2291

2696

if(ret_errno != 0){

2292

2697

errno = ret_errno;

2293

2698

perror_plus("argz_add");

2699

free(direntries[i]);

2294

2700

continue;

2295

2701

}

2296

2702

if(debug){

2297

2703

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

2298

2704

direntries[i]->d_name);

2299

2705

}

2706

free(direntries[i]);

2300

2707

}

2301

2708

free(direntries);

2302

2709

} else {

2303

free(direntries);

2710

if(ret == 0){

2711

free(direntries);

2712

}

2304

2713

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

2305

2714

exitcode = EXIT_FAILURE;

2306

2715

goto end;

2332

2741

errno = bring_up_interface(interface, delay);

2333

2742

if(not interface_was_up){

2334

2743

if(errno != 0){

2335

perror_plus("Failed to bring up interface");

2744

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

2745

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

2336

2746

} else {

2337

2747

errno = argz_add(&interfaces_to_take_down,

2338

2748

&interfaces_to_take_down_size,

2361

2771

goto end;

2362

2772

}

2363

2773

2364

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

2774

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

2365

2775

if(ret == -1){

2366

2776

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

2367

2777

exitcode = EX_UNAVAILABLE;

2570

2980

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

2571

2981

while(mc.current_server != NULL){

2572

2982

server *next = mc.current_server->next;

2983

#ifdef __GNUC__

2984

#pragma GCC diagnostic push

2985

#pragma GCC diagnostic ignored "-Wcast-qual"

2986

#endif

2987

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

2988

#ifdef __GNUC__

2989

#pragma GCC diagnostic pop

2990

#endif

2573

2991

free(mc.current_server);

2574

2992

mc.current_server = next;

2575

2993

}

2579

2997

{

2580

2998

ret_errno = raise_privileges();

2581

2999

if(ret_errno != 0){

3000

errno = ret_errno;

2582

3001

perror_plus("Failed to raise privileges");

2583

3002

} else {

2584

3003

2607

3026

2608

3027

ret_errno = lower_privileges_permanently();

2609

3028

if(ret_errno != 0){

3029

errno = ret_errno;

2610

3030

perror_plus("Failed to lower privileges permanently");

2611

3031

}

2612

3032

}

2617

3037

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

2618

3038

if(tempdir != NULL){

2619

3039

struct dirent **direntries = NULL;

2620

struct dirent *direntry = NULL;

2621

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

2622

alphasort);

2623

if(numentries > 0){

2624

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

2625

direntry = direntries[i];

2626

char *fullname = NULL;

2627

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

2628

direntry->d_name);

2629

if(ret < 0){

2630

perror_plus("asprintf");

2631

continue;

2632

}

2633

ret = remove(fullname);

2634

if(ret == -1){

2635

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

2636

strerror(errno));

2637

}

2638

free(fullname);

3040

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

3041

| O_NOFOLLOW

3042

| O_DIRECTORY

3043

| O_PATH));

3044

if(tempdir_fd == -1){

3045

perror_plus("open");

3046

} else {

3047

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

3048

notdotentries, alphasort);

3049

if(numentries >= 0){

3050

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

3051

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

3052

if(ret == -1){

3053

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

3054

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

3055

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

3056

}

3057

free(direntries[i]);

3058

}

3059

3060

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

3061

free(direntries);

3062

if(numentries == -1){

3063

perror_plus("scandir");

3064

}

3065

ret = rmdir(tempdir);

3066

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

3067

perror_plus("rmdir");

3068

}

2639

3069

}

2640

}

2641

2642

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

2643

free(direntries);

2644

if(numentries == -1){

2645

perror_plus("scandir");

2646

}

2647

ret = rmdir(tempdir);

2648

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

2649

perror_plus("rmdir");

3070

close(tempdir_fd);

2650

3071

}

2651

3072

}

2652

3073