/mandos/trunk : revision 850

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,

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(), unlinkat(), AT_REMOVEDIR */

61

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

62

*/

63

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

64

strtoimax() */

65

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

65

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

66

EAI_SYSTEM, ENETUNREACH,

67

EHOSTUNREACH, ECONNREFUSED, EPROTO,

68

EIO, ENOENT, ENXIO, ENOMEM, EISDIR,

69

ENOTEMPTY,

66

70

program_invocation_short_name */

67

71

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

68

72

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

305

309

return false;

306

310

}

307

311

308

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

312

ret = close(fd);

309

313

if(ret == -1){

310

314

perror_plus("close");

311

315

}

493

497

return plaintext_length;

494

498

}

495

499

500

__attribute__((warn_unused_result, const))

501

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

502

if(str == NULL)

503

return "(unknown)";

504

return str;

505

}

506

496

507

__attribute__((warn_unused_result))

497

508

static const char *safer_gnutls_strerror(int value){

498

509

const char *ret = gnutls_strerror(value);

499

if(ret == NULL)

500

ret = "(unknown)";

501

return ret;

510

return safe_string(ret);

502

511

}

503

512

504

513

/* GnuTLS log function callback */

508

517

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

509

518

}

510

519

511

__attribute__((nonnull, warn_unused_result))

520

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

512

521

static int init_gnutls_global(const char *pubkeyfilename,

513

522

const char *seckeyfilename,

523

const char *dhparamsfilename,

514

524

mandos_context *mc){

515

525

int ret;

526

unsigned int uret;

516

527

517

528

if(debug){

518

529

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

519

530

}

520

531

521

ret = gnutls_global_init();

522

if(ret != GNUTLS_E_SUCCESS){

523

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

524

safer_gnutls_strerror(ret));

525

return -1;

526

}

527

528

532

if(debug){

529

533

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

530

534

* - GnuTLS manual

538

542

if(ret != GNUTLS_E_SUCCESS){

539

543

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

540

544

safer_gnutls_strerror(ret));

541

gnutls_global_deinit();

542

545

return -1;

543

546

}

544

547

569

572

safer_gnutls_strerror(ret));

570

573

goto globalfail;

571

574

}

572

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

573

if(ret != GNUTLS_E_SUCCESS){

574

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

575

safer_gnutls_strerror(ret));

576

goto globalfail;

577

}

578

575

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

576

if(dhparamsfilename != NULL){

577

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

578

do {

579

int dhpfile = open(dhparamsfilename, O_RDONLY);

580

if(dhpfile == -1){

581

perror_plus("open");

582

dhparamsfilename = NULL;

583

break;

584

}

585

size_t params_capacity = 0;

586

while(true){

587

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

588

(size_t)params.size,

589

(size_t)params_capacity);

590

if(params_capacity == 0){

591

perror_plus("incbuffer");

592

free(params.data);

593

params.data = NULL;

594

dhparamsfilename = NULL;

595

break;

596

}

597

ssize_t bytes_read = read(dhpfile,

598

params.data + params.size,

599

BUFFER_SIZE);

600

/* EOF */

601

if(bytes_read == 0){

602

break;

603

}

604

/* check bytes_read for failure */

605

if(bytes_read < 0){

606

perror_plus("read");

607

free(params.data);

608

params.data = NULL;

609

dhparamsfilename = NULL;

610

break;

611

}

612

params.size += (unsigned int)bytes_read;

613

}

614

if(params.data == NULL){

615

dhparamsfilename = NULL;

616

}

617

if(dhparamsfilename == NULL){

618

break;

619

}

620

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

621

GNUTLS_X509_FMT_PEM);

622

if(ret != GNUTLS_E_SUCCESS){

623

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

624

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

625

safer_gnutls_strerror(ret));

626

dhparamsfilename = NULL;

627

}

628

} while(false);

629

}

630

if(dhparamsfilename == NULL){

631

if(mc->dh_bits == 0){

632

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

633

/* Try to read the private key file */

634

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

635

do {

636

int secfile = open(seckeyfilename, O_RDONLY);

637

if(secfile == -1){

638

perror_plus("open");

639

break;

640

}

641

size_t buffer_capacity = 0;

642

while(true){

643

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

644

(size_t)buffer.size,

645

(size_t)buffer_capacity);

646

if(buffer_capacity == 0){

647

perror_plus("incbuffer");

648

free(buffer.data);

649

buffer.data = NULL;

650

break;

651

}

652

ssize_t bytes_read = read(secfile,

653

buffer.data + buffer.size,

654

BUFFER_SIZE);

655

/* EOF */

656

if(bytes_read == 0){

657

break;

658

}

659

/* check bytes_read for failure */

660

if(bytes_read < 0){

661

perror_plus("read");

662

free(buffer.data);

663

buffer.data = NULL;

664

break;

665

}

666

buffer.size += (unsigned int)bytes_read;

667

}

668

close(secfile);

669

} while(false);

670

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

671

gnutls_sec_param_t sec_param = GNUTLS_SEC_PARAM_ULTRA;

672

if(buffer.data != NULL){

673

{

674

gnutls_openpgp_privkey_t privkey = NULL;

675

ret = gnutls_openpgp_privkey_init(&privkey);

676

if(ret != GNUTLS_E_SUCCESS){

677

fprintf_plus(stderr, "Error initializing OpenPGP key"

678

" structure: %s",

679

safer_gnutls_strerror(ret));

680

free(buffer.data);

681

buffer.data = NULL;

682

} else {

683

ret = gnutls_openpgp_privkey_import

684

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

685

if(ret != GNUTLS_E_SUCCESS){

686

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

687

safer_gnutls_strerror(ret));

688

privkey = NULL;

689

}

690

free(buffer.data);

691

buffer.data = NULL;

692

if(privkey != NULL){

693

/* Use private key to suggest an appropriate

694

sec_param */

695

sec_param = gnutls_openpgp_privkey_sec_param(privkey);

696

gnutls_openpgp_privkey_deinit(privkey);

697

if(debug){

698

fprintf_plus(stderr, "This OpenPGP key implies using"

699

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

700

safe_string(gnutls_sec_param_get_name

701

(sec_param)));

702

}

703

}

704

}

705

}

706

if(sec_param == GNUTLS_SEC_PARAM_UNKNOWN){

707

/* Err on the side of caution */

708

sec_param = GNUTLS_SEC_PARAM_ULTRA;

709

if(debug){

710

fprintf_plus(stderr, "Falling back to security parameter"

711

" \"%s\"\n",

712

safe_string(gnutls_sec_param_get_name

713

(sec_param)));

714

}

715

}

716

}

717

uret = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, sec_param);

718

if(uret != 0){

719

mc->dh_bits = uret;

720

if(debug){

721

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

722

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

723

safe_string(gnutls_sec_param_get_name

724

(sec_param)),

725

mc->dh_bits);

726

}

727

} else {

728

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

729

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

730

safe_string(gnutls_sec_param_get_name

731

(sec_param)),

732

safer_gnutls_strerror(ret));

733

goto globalfail;

734

}

735

} else if(debug){

736

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

737

mc->dh_bits);

738

}

739

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

740

if(ret != GNUTLS_E_SUCCESS){

741

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

742

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

743

safer_gnutls_strerror(ret));

744

goto globalfail;

745

}

746

}

579

747

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

580

748

581

749

return 0;

583

751

globalfail:

584

752

585

753

gnutls_certificate_free_credentials(mc->cred);

586

gnutls_global_deinit();

587

754

gnutls_dh_params_deinit(mc->dh_params);

588

755

return -1;

589

756

}

641

808

/* ignore client certificate if any. */

642

809

gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);

643

810

644

gnutls_dh_set_prime_bits(*session, mc->dh_bits);

645

646

811

return 0;

647

812

}

648

813

650

815

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

651

816

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

652

817

818

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

819

__attribute__((warn_unused_result))

820

int raise_privileges(void){

821

int old_errno = errno;

822

int ret = 0;

823

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

824

ret = errno;

825

}

826

errno = old_errno;

827

return ret;

828

}

829

830

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

831

__attribute__((warn_unused_result))

832

int raise_privileges_permanently(void){

833

int old_errno = errno;

834

int ret = raise_privileges();

835

if(ret != 0){

836

errno = old_errno;

837

return ret;

838

}

839

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

840

ret = errno;

841

}

842

errno = old_errno;

843

return ret;

844

}

845

846

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

847

__attribute__((warn_unused_result))

848

int lower_privileges(void){

849

int old_errno = errno;

850

int ret = 0;

851

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

852

ret = errno;

853

}

854

errno = old_errno;

855

return ret;

856

}

857

858

/* Lower privileges permanently */

859

__attribute__((warn_unused_result))

860

int lower_privileges_permanently(void){

861

int old_errno = errno;

862

int ret = 0;

863

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

864

ret = errno;

865

}

866

errno = old_errno;

867

return ret;

868

}

869

870

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

871

__attribute__((nonnull, warn_unused_result))

872

static bool add_delete_local_route(const bool add,

873

const char *address,

874

AvahiIfIndex if_index){

875

int ret;

876

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

877

char add_arg[] = "add";

878

char delete_arg[] = "delete";

879

char debug_flag[] = "--debug";

880

char *pluginhelperdir = getenv("MANDOSPLUGINHELPERDIR");

881

if(pluginhelperdir == NULL){

882

if(debug){

883

fprintf_plus(stderr, "MANDOSPLUGINHELPERDIR environment"

884

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

885

}

886

return false;

887

}

888

889

char interface[IF_NAMESIZE];

890

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

891

perror_plus("if_indextoname");

892

return false;

893

}

894

895

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

896

if(devnull == -1){

897

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

898

return false;

899

}

900

pid_t pid = fork();

901

if(pid == 0){

902

/* Child */

903

/* Raise privileges */

904

errno = raise_privileges_permanently();

905

if(errno != 0){

906

perror_plus("Failed to raise privileges");

907

/* _exit(EX_NOPERM); */

908

} else {

909

/* Set group */

910

errno = 0;

911

ret = setgid(0);

912

if(ret == -1){

913

perror_plus("setgid");

914

_exit(EX_NOPERM);

915

}

916

/* Reset supplementary groups */

917

errno = 0;

918

ret = setgroups(0, NULL);

919

if(ret == -1){

920

perror_plus("setgroups");

921

_exit(EX_NOPERM);

922

}

923

}

924

ret = dup2(devnull, STDIN_FILENO);

925

if(ret == -1){

926

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

927

_exit(EX_OSERR);

928

}

929

ret = close(devnull);

930

if(ret == -1){

931

perror_plus("close");

932

_exit(EX_OSERR);

933

}

934

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

935

if(ret == -1){

936

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

937

_exit(EX_OSERR);

938

}

939

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

940

O_RDONLY

941

| O_DIRECTORY

942

| O_PATH

943

| O_CLOEXEC));

944

if(helperdir_fd == -1){

945

perror_plus("open");

946

_exit(EX_UNAVAILABLE);

947

}

948

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

949

helper, O_RDONLY));

950

if(helper_fd == -1){

951

perror_plus("openat");

952

close(helperdir_fd);

953

_exit(EX_UNAVAILABLE);

954

}

955

close(helperdir_fd);

956

#ifdef __GNUC__

957

#pragma GCC diagnostic push

958

#pragma GCC diagnostic ignored "-Wcast-qual"

959

#endif

960

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

961

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

962

interface, debug ? debug_flag : NULL, NULL },

963

environ) == -1){

964

#ifdef __GNUC__

965

#pragma GCC diagnostic pop

966

#endif

967

perror_plus("fexecve");

968

_exit(EXIT_FAILURE);

969

}

970

}

971

if(pid == -1){

972

perror_plus("fork");

973

return false;

974

}

975

int status;

976

pid_t pret = -1;

977

errno = 0;

978

do {

979

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

980

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

981

int errno_raising = 0;

982

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

983

errno_raising = errno;

984

perror_plus("Failed to raise privileges in order to"

985

" kill helper program");

986

}

987

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

988

perror_plus("kill");

989

}

990

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

991

perror_plus("Failed to lower privileges after killing"

992

" helper program");

993

}

994

return false;

995

}

996

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

997

if(pret == -1){

998

perror_plus("waitpid");

999

return false;

1000

}

1001

if(WIFEXITED(status)){

1002

if(WEXITSTATUS(status) != 0){

1003

fprintf_plus(stderr, "Error: iprouteadddel exited"

1004

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

1005

return false;

1006

}

1007

return true;

1008

}

1009

if(WIFSIGNALED(status)){

1010

fprintf_plus(stderr, "Error: iprouteadddel died by"

1011

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

1012

return false;

1013

}

1014

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

1015

return false;

1016

}

1017

1018

__attribute__((nonnull, warn_unused_result))

1019

static bool add_local_route(const char *address,

1020

AvahiIfIndex if_index){

1021

if(debug){

1022

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

1023

}

1024

return add_delete_local_route(true, address, if_index);

1025

}

1026

1027

__attribute__((nonnull, warn_unused_result))

1028

static bool delete_local_route(const char *address,

1029

AvahiIfIndex if_index){

1030

if(debug){

1031

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

1032

}

1033

return add_delete_local_route(false, address, if_index);

1034

}

1035

653

1036

/* Called when a Mandos server is found */

654

1037

__attribute__((nonnull, warn_unused_result))

655

1038

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

666

1049

int retval = -1;

667

1050

gnutls_session_t session;

668

1051

int pf; /* Protocol family */

1052

bool route_added = false;

669

1053

670

1054

errno = 0;

671

1055

729

1113

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

730

1114

}

731

1115

732

tcp_sd = socket(pf, SOCK_STREAM, 0);

1116

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

733

1117

if(tcp_sd < 0){

734

1118

int e = errno;

735

1119

perror_plus("socket");

742

1126

goto mandos_end;

743

1127

}

744

1128

745

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

746

1129

if(af == AF_INET6){

747

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

748

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

1130

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

1131

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

1132

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

749

1133

} else { /* IPv4 */

750

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

751

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

1134

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

1135

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

1136

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

752

1137

}

753

1138

if(ret < 0 ){

754

1139

int e = errno;

824

1209

goto mandos_end;

825

1210

}

826

1211

827

if(af == AF_INET6){

828

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

829

sizeof(struct sockaddr_in6));

830

} else {

831

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

832

sizeof(struct sockaddr_in));

833

}

834

if(ret < 0){

835

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

836

int e = errno;

837

perror_plus("connect");

838

errno = e;

839

}

840

goto mandos_end;

841

}

842

843

if(quit_now){

844

errno = EINTR;

845

goto mandos_end;

1212

while(true){

1213

if(af == AF_INET6){

1214

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

1215

sizeof(struct sockaddr_in6));

1216

} else {

1217

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

1218

sizeof(struct sockaddr_in));

1219

}

1220

if(ret < 0){

1221

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

1222

and if_index != AVAHI_IF_UNSPEC

1223

and connect_to == NULL

1224

and not route_added and

1225

((af == AF_INET6 and not

1226

IN6_IS_ADDR_LINKLOCAL(&(((struct sockaddr_in6 *)

1227

&to)->sin6_addr)))

1228

or (af == AF_INET and

1229

/* Not a a IPv4LL address */

1230

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

1231

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

1232

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

1233

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

1234

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

1235

connect to a Mandos server announced by Avahi on a server

1236

host with a global address. Work around this by retrying

1237

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

1238

1239

Avahi bug reference:

1240

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

1241

https://bugs.debian.org/587961

1242

*/

1243

if(debug){

1244

fprintf_plus(stderr, "Mandos server unreachable, trying"

1245

" direct route\n");

1246

}

1247

int e = errno;

1248

route_added = add_local_route(ip, if_index);

1249

if(route_added){

1250

continue;

1251

}

1252

errno = e;

1253

}

1254

if(errno != ECONNREFUSED or debug){

1255

int e = errno;

1256

perror_plus("connect");

1257

errno = e;

1258

}

1259

goto mandos_end;

1260

}

1261

1262

if(quit_now){

1263

errno = EINTR;

1264

goto mandos_end;

1265

}

1266

break;

846

1267

}

847

1268

848

1269

const char *out = mandos_protocol_version;

1031

1452

1032

1453

mandos_end:

1033

1454

{

1455

if(route_added){

1456

if(not delete_local_route(ip, if_index)){

1457

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

1458

" interface %d", ip, if_index);

1459

}

1460

}

1034

1461

int e = errno;

1035

1462

free(decrypted_buffer);

1036

1463

free(buffer);

1037

1464

if(tcp_sd >= 0){

1038

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

1465

ret = close(tcp_sd);

1039

1466

}

1040

1467

if(ret == -1){

1041

1468

if(e == 0){

1196

1623

__attribute__((nonnull, warn_unused_result))

1197

1624

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

1198

1625

int ret;

1199

error_t ret_errno;

1626

int old_errno;

1200

1627

1201

1628

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

1202

1629

if(s < 0){

1203

ret_errno = errno;

1630

old_errno = errno;

1204

1631

perror_plus("socket");

1205

errno = ret_errno;

1632

errno = old_errno;

1206

1633

return false;

1207

1634

}

1208

strcpy(ifr->ifr_name, ifname);

1635

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

1636

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

1209

1637

ret = ioctl(s, SIOCGIFFLAGS, ifr);

1210

1638

if(ret == -1){

1211

1639

if(debug){

1212

ret_errno = errno;

1640

old_errno = errno;

1213

1641

perror_plus("ioctl SIOCGIFFLAGS");

1214

errno = ret_errno;

1642

errno = old_errno;

1215

1643

}

1216

1644

return false;

1217

1645

}

1462

1890

}

1463

1891

}

1464

1892

1465

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

1466

__attribute__((warn_unused_result))

1467

error_t raise_privileges(void){

1468

error_t old_errno = errno;

1469

error_t ret_errno = 0;

1470

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

1471

ret_errno = errno;

1472

}

1473

errno = old_errno;

1474

return ret_errno;

1475

}

1476

1477

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

1478

__attribute__((warn_unused_result))

1479

error_t raise_privileges_permanently(void){

1480

error_t old_errno = errno;

1481

error_t ret_errno = raise_privileges();

1482

if(ret_errno != 0){

1483

errno = old_errno;

1484

return ret_errno;

1485

}

1486

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

1487

ret_errno = errno;

1488

}

1489

errno = old_errno;

1490

return ret_errno;

1491

}

1492

1493

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

1494

__attribute__((warn_unused_result))

1495

error_t lower_privileges(void){

1496

error_t old_errno = errno;

1497

error_t ret_errno = 0;

1498

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

1499

ret_errno = errno;

1500

}

1501

errno = old_errno;

1502

return ret_errno;

1503

}

1504

1505

/* Lower privileges permanently */

1506

__attribute__((warn_unused_result))

1507

error_t lower_privileges_permanently(void){

1508

error_t old_errno = errno;

1509

error_t ret_errno = 0;

1510

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

1511

ret_errno = errno;

1512

}

1513

errno = old_errno;

1514

return ret_errno;

1515

}

1516

1517

1893

__attribute__((nonnull))

1518

1894

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

1519

1895

const float delay){

1520

1896

struct dirent **direntries = NULL;

1521

1897

if(hookdir_fd == -1){

1522

hookdir_fd = open(hookdir, O_RDONLY);

1898

hookdir_fd = open(hookdir, O_RDONLY | O_DIRECTORY | O_PATH

1899

| O_CLOEXEC);

1523

1900

if(hookdir_fd == -1){

1524

1901

if(errno == ENOENT){

1525

1902

if(debug){

1532

1909

return;

1533

1910

}

1534

1911

}

1535

#ifdef __GLIBC__

1536

#if __GLIBC_PREREQ(2, 15)

1537

1912

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

1538

1913

runnable_hook, alphasort);

1539

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

1540

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

1541

alphasort);

1542

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

1543

#else /* not __GLIBC__ */

1544

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

1545

alphasort);

1546

#endif /* not __GLIBC__ */

1547

1914

if(numhooks == -1){

1548

1915

perror_plus("scandir");

1549

1916

return;

1550

1917

}

1551

1918

struct dirent *direntry;

1552

1919

int ret;

1553

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

1920

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

1921

if(devnull == -1){

1922

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

1923

return;

1924

}

1554

1925

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

1555

1926

direntry = direntries[i];

1556

1927

if(debug){

1580

1951

perror_plus("setgroups");

1581

1952

_exit(EX_NOPERM);

1582

1953

}

1583

ret = dup2(devnull, STDIN_FILENO);

1584

if(ret == -1){

1585

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

1586

_exit(EX_OSERR);

1587

}

1588

ret = close(devnull);

1589

if(ret == -1){

1590

perror_plus("close");

1591

_exit(EX_OSERR);

1592

}

1593

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

1594

if(ret == -1){

1595

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

1596

_exit(EX_OSERR);

1597

}

1598

1954

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

1599

1955

if(ret == -1){

1600

1956

perror_plus("setenv");

1635

1991

_exit(EX_OSERR);

1636

1992

}

1637

1993

}

1638

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

1994

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

1995

direntry->d_name,

1996

O_RDONLY));

1639

1997

if(hook_fd == -1){

1640

1998

perror_plus("openat");

1641

1999

_exit(EXIT_FAILURE);

1642

2000

}

1643

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

2001

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

1644

2002

perror_plus("close");

1645

2003

_exit(EXIT_FAILURE);

1646

2004

}

2005

ret = dup2(devnull, STDIN_FILENO);

2006

if(ret == -1){

2007

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

2008

_exit(EX_OSERR);

2009

}

2010

ret = close(devnull);

2011

if(ret == -1){

2012

perror_plus("close");

2013

_exit(EX_OSERR);

2014

}

2015

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

2016

if(ret == -1){

2017

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

2018

_exit(EX_OSERR);

2019

}

1647

2020

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

1648

2021

environ) == -1){

1649

2022

perror_plus("fexecve");

1650

2023

_exit(EXIT_FAILURE);

1651

2024

}

1652

2025

} else {

2026

if(hook_pid == -1){

2027

perror_plus("fork");

2028

free(direntry);

2029

continue;

2030

}

1653

2031

int status;

1654

2032

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

1655

2033

perror_plus("waitpid");

1684

2062

free(direntry);

1685

2063

}

1686

2064

free(direntries);

1687

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

2065

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

1688

2066

perror_plus("close");

1689

2067

} else {

1690

2068

hookdir_fd = -1;

1693

2071

}

1694

2072

1695

2073

__attribute__((nonnull, warn_unused_result))

1696

error_t bring_up_interface(const char *const interface,

1697

const float delay){

1698

error_t old_errno = errno;

2074

int bring_up_interface(const char *const interface,

2075

const float delay){

2076

int old_errno = errno;

1699

2077

int ret;

1700

2078

struct ifreq network;

1701

2079

unsigned int if_index = if_nametoindex(interface);

1711

2089

}

1712

2090

1713

2091

if(not interface_is_up(interface)){

1714

error_t ret_errno = 0, ioctl_errno = 0;

2092

int ret_errno = 0;

2093

int ioctl_errno = 0;

1715

2094

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

1716

2095

ret_errno = errno;

1717

2096

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

1730

2109

}

1731

2110

1732

2111

if(quit_now){

1733

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

2112

ret = close(sd);

1734

2113

if(ret == -1){

1735

2114

perror_plus("close");

1736

2115

}

1786

2165

}

1787

2166

1788

2167

/* Close the socket */

1789

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

2168

ret = close(sd);

1790

2169

if(ret == -1){

1791

2170

perror_plus("close");

1792

2171

}

1820

2199

}

1821

2200

1822

2201

__attribute__((nonnull, warn_unused_result))

1823

error_t take_down_interface(const char *const interface){

1824

error_t old_errno = errno;

2202

int take_down_interface(const char *const interface){

2203

int old_errno = errno;

1825

2204

struct ifreq network;

1826

2205

unsigned int if_index = if_nametoindex(interface);

1827

2206

if(if_index == 0){

1830

2209

return ENXIO;

1831

2210

}

1832

2211

if(interface_is_up(interface)){

1833

error_t ret_errno = 0, ioctl_errno = 0;

2212

int ret_errno = 0;

2213

int ioctl_errno = 0;

1834

2214

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

1835

2215

ret_errno = errno;

1836

2216

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

1874

2254

}

1875

2255

1876

2256

/* Close the socket */

1877

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

2257

int ret = close(sd);

1878

2258

if(ret == -1){

1879

2259

perror_plus("close");

1880

2260

}

1895

2275

}

1896

2276

1897

2277

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

1898

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

1899

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

1900

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

1901

.interfaces = NULL, .interfaces_size = 0 };

2278

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

2279

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

2280

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

2281

.current_server = NULL, .interfaces = NULL,

2282

.interfaces_size = 0 };

1902

2283

AvahiSServiceBrowser *sb = NULL;

1903

2284

error_t ret_errno;

1904

2285

int ret;

1913

2294

AvahiIfIndex if_index = AVAHI_IF_UNSPEC;

1914

2295

const char *seckey = PATHDIR "/" SECKEY;

1915

2296

const char *pubkey = PATHDIR "/" PUBKEY;

2297

const char *dh_params_file = NULL;

1916

2298

char *interfaces_hooks = NULL;

1917

2299

1918

2300

bool gnutls_initialized = false;

1971

2353

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

1972

2354

" Diffie-Hellman key exchange",

1973

2355

.group = 2 },

2356

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

2357

.arg = "FILE",

2358

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

2359

" for the Diffie-Hellman key exchange",

2360

.group = 2 },

1974

2361

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

1975

2362

.arg = "STRING",

1976

2363

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

2031

2418

}

2032

2419

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

2033

2420

break;

2421

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

2422

dh_params_file = arg;

2423

break;

2034

2424

case 130: /* --priority */

2035

2425

mc.priority = arg;

2036

2426

break;

2076

2466

.args_doc = "",

2077

2467

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

2078

2468

" passwords from a Mandos server" };

2079

ret = argp_parse(&argp, argc, argv,

2080

ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);

2081

switch(ret){

2469

ret_errno = argp_parse(&argp, argc, argv,

2470

ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);

2471

switch(ret_errno){

2082

2472

case 0:

2083

2473

break;

2084

2474

case ENOMEM:

2085

2475

default:

2086

errno = ret;

2476

errno = ret_errno;

2087

2477

perror_plus("argp_parse");

2088

2478

exitcode = EX_OSERR;

2089

2479

goto end;

2092

2482

goto end;

2093

2483

}

2094

2484

}

2095

2485

2096

2486

{

2097

2487

/* Work around Debian bug #633582:

2098

2488

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

2099

2489

2100

2490

/* Re-raise privileges */

2101

ret_errno = raise_privileges();

2102

if(ret_errno != 0){

2103

errno = ret_errno;

2491

ret = raise_privileges();

2492

if(ret != 0){

2493

errno = ret;

2104

2494

perror_plus("Failed to raise privileges");

2105

2495

} else {

2106

2496

struct stat st;

2122

2512

}

2123

2513

}

2124

2514

}

2125

TEMP_FAILURE_RETRY(close(seckey_fd));

2515

close(seckey_fd);

2126

2516

}

2127

2517

}

2128

2518

2129

2519

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

2130

2520

int pubkey_fd = open(pubkey, O_RDONLY);

2131

2521

if(pubkey_fd == -1){

2143

2533

}

2144

2534

}

2145

2535

}

2146

TEMP_FAILURE_RETRY(close(pubkey_fd));

2147

}

2148

}

2149

2536

close(pubkey_fd);

2537

}

2538

}

2539

2540

if(dh_params_file != NULL

2541

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

2542

int dhparams_fd = open(dh_params_file, O_RDONLY);

2543

if(dhparams_fd == -1){

2544

perror_plus("open");

2545

} else {

2546

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

2547

if(ret == -1){

2548

perror_plus("fstat");

2549

} else {

2550

if(S_ISREG(st.st_mode)

2551

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

2552

ret = fchown(dhparams_fd, uid, gid);

2553

if(ret == -1){

2554

perror_plus("fchown");

2555

}

2556

}

2557

}

2558

close(dhparams_fd);

2559

}

2560

}

2561

2150

2562

/* Lower privileges */

2151

ret_errno = lower_privileges();

2152

if(ret_errno != 0){

2153

errno = ret_errno;

2563

ret = lower_privileges();

2564

if(ret != 0){

2565

errno = ret;

2154

2566

perror_plus("Failed to lower privileges");

2155

2567

}

2156

2568

}

2326

2738

errno = bring_up_interface(interface, delay);

2327

2739

if(not interface_was_up){

2328

2740

if(errno != 0){

2329

perror_plus("Failed to bring up interface");

2741

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

2742

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

2330

2743

} else {

2331

2744

errno = argz_add(&interfaces_to_take_down,

2332

2745

&interfaces_to_take_down_size,

2355

2768

goto end;

2356

2769

}

2357

2770

2358

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

2771

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

2359

2772

if(ret == -1){

2360

2773

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

2361

2774

exitcode = EX_UNAVAILABLE;

2483

2896

2484

2897

/* Allocate a new server */

2485

2898

mc.server = avahi_server_new(avahi_simple_poll_get(simple_poll),

2486

&config, NULL, NULL, &ret_errno);

2899

&config, NULL, NULL, &ret);

2487

2900

2488

2901

/* Free the Avahi configuration data */

2489

2902

avahi_server_config_free(&config);

2492

2905

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

2493

2906

if(mc.server == NULL){

2494

2907

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

2495

avahi_strerror(ret_errno));

2908

avahi_strerror(ret));

2496

2909

exitcode = EX_UNAVAILABLE;

2497

2910

goto end;

2498

2911

}

2550

2963

2551

2964

if(gnutls_initialized){

2552

2965

gnutls_certificate_free_credentials(mc.cred);

2553

gnutls_global_deinit();

2554

2966

gnutls_dh_params_deinit(mc.dh_params);

2555

2967

}

2556

2968

2579

2991

2580

2992

/* Re-raise privileges */

2581

2993

{

2582

ret_errno = raise_privileges();

2583

if(ret_errno != 0){

2584

errno = ret_errno;

2994

ret = raise_privileges();

2995

if(ret != 0){

2996

errno = ret;

2585

2997

perror_plus("Failed to raise privileges");

2586

2998

} else {

2587

2999

2595

3007

while((interface=argz_next(interfaces_to_take_down,

2596

3008

interfaces_to_take_down_size,

2597

3009

interface))){

2598

ret_errno = take_down_interface(interface);

2599

if(ret_errno != 0){

2600

errno = ret_errno;

3010

ret = take_down_interface(interface);

3011

if(ret != 0){

3012

errno = ret;

2601

3013

perror_plus("Failed to take down interface");

2602

3014

}

2603

3015

}

2608

3020

}

2609

3021

}

2610

3022

2611

ret_errno = lower_privileges_permanently();

2612

if(ret_errno != 0){

2613

errno = ret_errno;

3023

ret = lower_privileges_permanently();

3024

if(ret != 0){

3025

errno = ret;

2614

3026

perror_plus("Failed to lower privileges permanently");

2615

3027

}

2616

3028

}

2618

3030

free(interfaces_to_take_down);

2619

3031

free(interfaces_hooks);

2620

3032

3033

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

3034

uintmax_t level){

3035

struct dirent **direntries = NULL;

3036

int dret;

3037

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

3038

O_RDONLY

3039

| O_NOFOLLOW

3040

| O_DIRECTORY

3041

| O_PATH));

3042

if(dir_fd == -1){

3043

perror_plus("open");

3044

}

3045

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

3046

notdotentries, alphasort);

3047

if(numentries >= 0){

3048

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

3049

if(debug){

3050

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

3051

dirname, direntries[i]->d_name);

3052

}

3053

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

3054

if(dret == -1){

3055

if(errno == EISDIR){

3056

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

3057

AT_REMOVEDIR);

3058

}

3059

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

3060

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

3061

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

3062

/* Recurse only in this special case */

3063

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

3064

dret = 0;

3065

}

3066

if(dret == -1){

3067

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

3068

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

3069

}

3070

}

3071

free(direntries[i]);

3072

}

3073

3074

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

3075

free(direntries);

3076

if(numentries == -1){

3077

perror_plus("scandirat");

3078

}

3079

dret = unlinkat(base, dirname, AT_REMOVEDIR);

3080

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

3081

perror_plus("rmdir");

3082

}

3083

} else {

3084

perror_plus("scandirat");

3085

}

3086

close(dir_fd);

3087

}

3088

2621

3089

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

2622

3090

if(tempdir != NULL){

2623

struct dirent **direntries = NULL;

2624

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

2625

O_NOFOLLOW));

2626

if(tempdir_fd == -1){

2627

perror_plus("open");

2628

} else {

2629

#ifdef __GLIBC__

2630

#if __GLIBC_PREREQ(2, 15)

2631

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

2632

notdotentries, alphasort);

2633

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

2634

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

2635

alphasort);

2636

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

2637

#else /* not __GLIBC__ */

2638

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

2639

alphasort);

2640

#endif /* not __GLIBC__ */

2641

if(numentries >= 0){

2642

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

2643

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

2644

if(ret == -1){

2645

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

2646

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

2647

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

2648

}

2649

free(direntries[i]);

2650

}

2651

2652

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

2653

free(direntries);

2654

if(numentries == -1){

2655

perror_plus("scandir");

2656

}

2657

ret = rmdir(tempdir);

2658

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

2659

perror_plus("rmdir");

2660

}

2661

}

2662

TEMP_FAILURE_RETRY(close(tempdir_fd));

2663

}

3091

clean_dir_at(-1, tempdir, 0);

2664

3092

}

2665

3093

2666

3094

if(quit_now){