/mandos/trunk : revision 721

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

50

asprintf(), strncpy() */

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(), AT_REMOVEDIR */

60

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

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, EINTR, EINVAL,

66

EAI_SYSTEM, ENETUNREACH,

67

EHOSTUNREACH, ECONNREFUSED, EPROTO,

68

EIO, ENOENT, ENXIO, ENOMEM, EISDIR,

69

ENOTEMPTY,

65

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

70

66

program_invocation_short_name */

71

67

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

72

68

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

309

305

return false;

310

306

}

311

307

312

ret = close(fd);

308

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

313

309

if(ret == -1){

314

310

perror_plus("close");

315

311

}

497

493

return plaintext_length;

498

494

}

499

495

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

507

496

__attribute__((warn_unused_result))

508

497

static const char *safer_gnutls_strerror(int value){

509

498

const char *ret = gnutls_strerror(value);

510

return safe_string(ret);

499

if(ret == NULL)

500

ret = "(unknown)";

501

return ret;

511

502

}

512

503

513

504

/* GnuTLS log function callback */

517

508

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

518

509

}

519

510

520

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

511

__attribute__((nonnull, warn_unused_result))

521

512

static int init_gnutls_global(const char *pubkeyfilename,

522

513

const char *seckeyfilename,

523

const char *dhparamsfilename,

524

514

mandos_context *mc){

525

515

int ret;

526

unsigned int uret;

527

516

528

517

if(debug){

529

518

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

530

519

}

531

520

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

532

528

if(debug){

533

529

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

534

530

* - GnuTLS manual

542

538

if(ret != GNUTLS_E_SUCCESS){

543

539

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

544

540

safer_gnutls_strerror(ret));

541

gnutls_global_deinit();

545

542

return -1;

546

543

}

547

544

572

569

safer_gnutls_strerror(ret));

573

570

goto globalfail;

574

571

}

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

}

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

747

579

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

748

580

749

581

return 0;

751

583

globalfail:

752

584

753

585

gnutls_certificate_free_credentials(mc->cred);

586

gnutls_global_deinit();

754

587

gnutls_dh_params_deinit(mc->dh_params);

755

588

return -1;

756

589

}

808

641

/* ignore client certificate if any. */

809

642

gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);

810

643

644

gnutls_dh_set_prime_bits(*session, mc->dh_bits);

645

811

646

return 0;

812

647

}

813

648

815

650

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

816

651

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

817

652

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

1036

653

/* Called when a Mandos server is found */

1037

654

__attribute__((nonnull, warn_unused_result))

1038

655

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

1049

666

int retval = -1;

1050

667

gnutls_session_t session;

1051

668

int pf; /* Protocol family */

1052

bool route_added = false;

1053

669

1054

670

errno = 0;

1055

671

1113

729

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

1114

730

}

1115

731

1116

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

732

tcp_sd = socket(pf, SOCK_STREAM, 0);

1117

733

if(tcp_sd < 0){

1118

734

int e = errno;

1119

735

perror_plus("socket");

1126

742

goto mandos_end;

1127

743

}

1128

744

745

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

1129

746

if(af == AF_INET6){

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);

747

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

748

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

1133

749

} else { /* IPv4 */

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);

750

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

751

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

1137

752

}

1138

753

if(ret < 0 ){

1139

754

int e = errno;

1209

824

goto mandos_end;

1210

825

}

1211

826

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;

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;

1267

846

}

1268

847

1269

848

const char *out = mandos_protocol_version;

1452

1031

1453

1032

mandos_end:

1454

1033

{

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

}

1461

1034

int e = errno;

1462

1035

free(decrypted_buffer);

1463

1036

free(buffer);

1464

1037

if(tcp_sd >= 0){

1465

ret = close(tcp_sd);

1038

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

1466

1039

}

1467

1040

if(ret == -1){

1468

1041

if(e == 0){

1623

1196

__attribute__((nonnull, warn_unused_result))

1624

1197

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

1625

1198

int ret;

1626

int old_errno;

1199

error_t ret_errno;

1627

1200

1628

1201

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

1629

1202

if(s < 0){

1630

old_errno = errno;

1203

ret_errno = errno;

1631

1204

perror_plus("socket");

1632

errno = old_errno;

1205

errno = ret_errno;

1633

1206

return false;

1634

1207

}

1635

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

1636

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

1208

strcpy(ifr->ifr_name, ifname);

1637

1209

ret = ioctl(s, SIOCGIFFLAGS, ifr);

1638

1210

if(ret == -1){

1639

1211

if(debug){

1640

old_errno = errno;

1212

ret_errno = errno;

1641

1213

perror_plus("ioctl SIOCGIFFLAGS");

1642

errno = old_errno;

1214

errno = ret_errno;

1643

1215

}

1644

1216

return false;

1645

1217

}

1890

1462

}

1891

1463

}

1892

1464

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

1893

1517

__attribute__((nonnull))

1894

1518

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

1895

1519

const float delay){

1896

1520

struct dirent **direntries = NULL;

1897

1521

if(hookdir_fd == -1){

1898

hookdir_fd = open(hookdir, O_RDONLY | O_DIRECTORY | O_PATH

1899

| O_CLOEXEC);

1522

hookdir_fd = open(hookdir, O_RDONLY);

1900

1523

if(hookdir_fd == -1){

1901

1524

if(errno == ENOENT){

1902

1525

if(debug){

1909

1532

return;

1910

1533

}

1911

1534

}

1535

#ifdef __GLIBC__

1536

#if __GLIBC_PREREQ(2, 15)

1912

1537

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

1913

1538

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__ */

1914

1547

if(numhooks == -1){

1915

1548

perror_plus("scandir");

1916

1549

return;

1917

1550

}

1918

1551

struct dirent *direntry;

1919

1552

int ret;

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

}

1553

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

1925

1554

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

1926

1555

direntry = direntries[i];

1927

1556

if(debug){

1951

1580

perror_plus("setgroups");

1952

1581

_exit(EX_NOPERM);

1953

1582

}

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

}

1954

1598

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

1955

1599

if(ret == -1){

1956

1600

perror_plus("setenv");

1991

1635

_exit(EX_OSERR);

1992

1636

}

1993

1637

}

1994

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

1995

direntry->d_name,

1996

O_RDONLY));

1638

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

1997

1639

if(hook_fd == -1){

1998

1640

perror_plus("openat");

1999

1641

_exit(EXIT_FAILURE);

2000

1642

}

2001

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

1643

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

2002

1644

perror_plus("close");

2003

1645

_exit(EXIT_FAILURE);

2004

1646

}

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

}

2020

1647

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

2021

1648

environ) == -1){

2022

1649

perror_plus("fexecve");

2023

1650

_exit(EXIT_FAILURE);

2024

1651

}

2025

1652

} else {

2026

if(hook_pid == -1){

2027

perror_plus("fork");

2028

free(direntry);

2029

continue;

2030

}

2031

1653

int status;

2032

1654

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

2033

1655

perror_plus("waitpid");

2062

1684

free(direntry);

2063

1685

}

2064

1686

free(direntries);

2065

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

1687

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

2066

1688

perror_plus("close");

2067

1689

} else {

2068

1690

hookdir_fd = -1;

2071

1693

}

2072

1694

2073

1695

__attribute__((nonnull, warn_unused_result))

2074

int bring_up_interface(const char *const interface,

2075

const float delay){

2076

int old_errno = errno;

1696

error_t bring_up_interface(const char *const interface,

1697

const float delay){

1698

error_t old_errno = errno;

2077

1699

int ret;

2078

1700

struct ifreq network;

2079

1701

unsigned int if_index = if_nametoindex(interface);

2089

1711

}

2090

1712

2091

1713

if(not interface_is_up(interface)){

2092

int ret_errno = 0;

2093

int ioctl_errno = 0;

1714

error_t ret_errno = 0, ioctl_errno = 0;

2094

1715

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

2095

1716

ret_errno = errno;

2096

1717

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

2109

1730

}

2110

1731

2111

1732

if(quit_now){

2112

ret = close(sd);

1733

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

2113

1734

if(ret == -1){

2114

1735

perror_plus("close");

2115

1736

}

2165

1786

}

2166

1787

2167

1788

/* Close the socket */

2168

ret = close(sd);

1789

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

2169

1790

if(ret == -1){

2170

1791

perror_plus("close");

2171

1792

}

2199

1820

}

2200

1821

2201

1822

__attribute__((nonnull, warn_unused_result))

2202

int take_down_interface(const char *const interface){

2203

int old_errno = errno;

1823

error_t take_down_interface(const char *const interface){

1824

error_t old_errno = errno;

2204

1825

struct ifreq network;

2205

1826

unsigned int if_index = if_nametoindex(interface);

2206

1827

if(if_index == 0){

2209

1830

return ENXIO;

2210

1831

}

2211

1832

if(interface_is_up(interface)){

2212

int ret_errno = 0;

2213

int ioctl_errno = 0;

1833

error_t ret_errno = 0, ioctl_errno = 0;

2214

1834

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

2215

1835

ret_errno = errno;

2216

1836

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

2254

1874

}

2255

1875

2256

1876

/* Close the socket */

2257

int ret = close(sd);

1877

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

2258

1878

if(ret == -1){

2259

1879

perror_plus("close");

2260

1880

}

2275

1895

}

2276

1896

2277

1897

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

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 };

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 };

2283

1902

AvahiSServiceBrowser *sb = NULL;

2284

1903

error_t ret_errno;

2285

1904

int ret;

2294

1913

AvahiIfIndex if_index = AVAHI_IF_UNSPEC;

2295

1914

const char *seckey = PATHDIR "/" SECKEY;

2296

1915

const char *pubkey = PATHDIR "/" PUBKEY;

2297

const char *dh_params_file = NULL;

2298

1916

char *interfaces_hooks = NULL;

2299

1917

2300

1918

bool gnutls_initialized = false;

2353

1971

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

2354

1972

" Diffie-Hellman key exchange",

2355

1973

.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 },

2361

1974

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

2362

1975

.arg = "STRING",

2363

1976

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

2418

2031

}

2419

2032

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

2420

2033

break;

2421

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

2422

dh_params_file = arg;

2423

break;

2424

2034

case 130: /* --priority */

2425

2035

mc.priority = arg;

2426

2036

break;

2466

2076

.args_doc = "",

2467

2077

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

2468

2078

" passwords from a Mandos server" };

2469

ret_errno = argp_parse(&argp, argc, argv,

2470

ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);

2471

switch(ret_errno){

2079

ret = argp_parse(&argp, argc, argv,

2080

ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);

2081

switch(ret){

2472

2082

case 0:

2473

2083

break;

2474

2084

case ENOMEM:

2475

2085

default:

2476

errno = ret_errno;

2086

errno = ret;

2477

2087

perror_plus("argp_parse");

2478

2088

exitcode = EX_OSERR;

2479

2089

goto end;

2482

2092

goto end;

2483

2093

}

2484

2094

}

2485

2095

2486

2096

{

2487

2097

/* Work around Debian bug #633582:

2488

2098

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

2489

2099

2490

2100

/* Re-raise privileges */

2491

ret = raise_privileges();

2492

if(ret != 0){

2493

errno = ret;

2101

ret_errno = raise_privileges();

2102

if(ret_errno != 0){

2103

errno = ret_errno;

2494

2104

perror_plus("Failed to raise privileges");

2495

2105

} else {

2496

2106

struct stat st;

2512

2122

}

2513

2123

}

2514

2124

}

2515

close(seckey_fd);

2125

TEMP_FAILURE_RETRY(close(seckey_fd));

2516

2126

}

2517

2127

}

2518

2128

2519

2129

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

2520

2130

int pubkey_fd = open(pubkey, O_RDONLY);

2521

2131

if(pubkey_fd == -1){

2533

2143

}

2534

2144

}

2535

2145

}

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

2146

TEMP_FAILURE_RETRY(close(pubkey_fd));

2147

}

2148

}

2149

2562

2150

/* Lower privileges */

2563

ret = lower_privileges();

2564

if(ret != 0){

2565

errno = ret;

2151

ret_errno = lower_privileges();

2152

if(ret_errno != 0){

2153

errno = ret_errno;

2566

2154

perror_plus("Failed to lower privileges");

2567

2155

}

2568

2156

}

2738

2326

errno = bring_up_interface(interface, delay);

2739

2327

if(not interface_was_up){

2740

2328

if(errno != 0){

2741

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

2742

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

2329

perror_plus("Failed to bring up interface");

2743

2330

} else {

2744

2331

errno = argz_add(&interfaces_to_take_down,

2745

2332

&interfaces_to_take_down_size,

2768

2355

goto end;

2769

2356

}

2770

2357

2771

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

2358

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

2772

2359

if(ret == -1){

2773

2360

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

2774

2361

exitcode = EX_UNAVAILABLE;

2896

2483

2897

2484

/* Allocate a new server */

2898

2485

mc.server = avahi_server_new(avahi_simple_poll_get(simple_poll),

2899

&config, NULL, NULL, &ret);

2486

&config, NULL, NULL, &ret_errno);

2900

2487

2901

2488

/* Free the Avahi configuration data */

2902

2489

avahi_server_config_free(&config);

2905

2492

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

2906

2493

if(mc.server == NULL){

2907

2494

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

2908

avahi_strerror(ret));

2495

avahi_strerror(ret_errno));

2909

2496

exitcode = EX_UNAVAILABLE;

2910

2497

goto end;

2911

2498

}

2963

2550

2964

2551

if(gnutls_initialized){

2965

2552

gnutls_certificate_free_credentials(mc.cred);

2553

gnutls_global_deinit();

2966

2554

gnutls_dh_params_deinit(mc.dh_params);

2967

2555

}

2968

2556

2991

2579

2992

2580

/* Re-raise privileges */

2993

2581

{

2994

ret = raise_privileges();

2995

if(ret != 0){

2996

errno = ret;

2582

ret_errno = raise_privileges();

2583

if(ret_errno != 0){

2584

errno = ret_errno;

2997

2585

perror_plus("Failed to raise privileges");

2998

2586

} else {

2999

2587

3007

2595

while((interface=argz_next(interfaces_to_take_down,

3008

2596

interfaces_to_take_down_size,

3009

2597

interface))){

3010

ret = take_down_interface(interface);

3011

if(ret != 0){

3012

errno = ret;

2598

ret_errno = take_down_interface(interface);

2599

if(ret_errno != 0){

2600

errno = ret_errno;

3013

2601

perror_plus("Failed to take down interface");

3014

2602

}

3015

2603

}

3020

2608

}

3021

2609

}

3022

2610

3023

ret = lower_privileges_permanently();

3024

if(ret != 0){

3025

errno = ret;

2611

ret_errno = lower_privileges_permanently();

2612

if(ret_errno != 0){

2613

errno = ret_errno;

3026

2614

perror_plus("Failed to lower privileges permanently");

3027

2615

}

3028

2616

}

3030

2618

free(interfaces_to_take_down);

3031

2619

free(interfaces_hooks);

3032

2620

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

3089

2621

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

3090

2622

if(tempdir != NULL){

3091

clean_dir_at(-1, tempdir, 0);

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

}

3092

2664

}

3093

2665

3094

2666

if(quit_now){