/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

}

513

517

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

514

518

}

515

519

516

__attribute__((nonnull, warn_unused_result))

520

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

517

521

static int init_gnutls_global(const char *pubkeyfilename,

518

522

const char *seckeyfilename,

523

const char *dhparamsfilename,

519

524

mandos_context *mc){

520

525

int ret;

521

526

unsigned int uret;

524

529

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

525

530

}

526

531

527

ret = gnutls_global_init();

528

if(ret != GNUTLS_E_SUCCESS){

529

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

530

safer_gnutls_strerror(ret));

531

return -1;

532

}

533

534

532

if(debug){

535

533

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

536

534

* - GnuTLS manual

544

542

if(ret != GNUTLS_E_SUCCESS){

545

543

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

546

544

safer_gnutls_strerror(ret));

547

gnutls_global_deinit();

548

545

return -1;

549

546

}

550

547

575

572

safer_gnutls_strerror(ret));

576

573

goto globalfail;

577

574

}

578

if(mc->dh_bits == 0){

579

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

580

/* Try to read the private key file */

581

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

582

{

583

int secfile = open(seckeyfilename, O_RDONLY);

584

size_t buffer_capacity = 0;

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;

585

586

while(true){

586

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

587

(size_t)buffer.size,

588

(size_t)buffer_capacity);

589

if(buffer_capacity == 0){

587

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

588

(size_t)params.size,

589

(size_t)params_capacity);

590

if(params_capacity == 0){

590

591

perror_plus("incbuffer");

591

free(buffer.data);

592

buffer.data = NULL;

592

free(params.data);

593

params.data = NULL;

594

dhparamsfilename = NULL;

593

595

break;

594

596

}

595

ssize_t bytes_read = read(secfile, buffer.data + buffer.size,

597

ssize_t bytes_read = read(dhpfile,

598

params.data + params.size,

596

599

BUFFER_SIZE);

597

600

/* EOF */

598

601

if(bytes_read == 0){

601

604

/* check bytes_read for failure */

602

605

if(bytes_read < 0){

603

606

perror_plus("read");

604

free(buffer.data);

605

buffer.data = NULL;

606

break;

607

}

608

buffer.size += (unsigned int)bytes_read;

609

}

610

close(secfile);

611

}

612

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

613

gnutls_sec_param_t sec_param = GNUTLS_SEC_PARAM_ULTRA;

614

if(buffer.data != NULL){

615

{

616

gnutls_openpgp_privkey_t privkey = NULL;

617

ret = gnutls_openpgp_privkey_init(&privkey);

618

if(ret != GNUTLS_E_SUCCESS){

619

fprintf_plus(stderr, "Error initializing OpenPGP key"

620

" structure: %s", safer_gnutls_strerror(ret));

621

free(buffer.data);

622

buffer.data = NULL;

623

} else {

624

ret = gnutls_openpgp_privkey_import(privkey, &buffer,

625

GNUTLS_OPENPGP_FMT_BASE64,

626

"", 0);

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);

627

676

if(ret != GNUTLS_E_SUCCESS){

628

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

677

fprintf_plus(stderr, "Error initializing OpenPGP key"

678

" structure: %s",

629

679

safer_gnutls_strerror(ret));

630

privkey = NULL;

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

}

631

704

}

632

free(buffer.data);

633

buffer.data = NULL;

634

if(privkey != NULL){

635

/* Use private key to suggest an appropriate sec_param */

636

sec_param = gnutls_openpgp_privkey_sec_param(privkey);

637

gnutls_openpgp_privkey_deinit(privkey);

638

if(debug){

639

fprintf_plus(stderr, "This OpenPGP key implies using a"

640

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

641

safe_string(gnutls_sec_param_get_name

642

(sec_param)));

643

}

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)));

644

714

}

645

715

}

646

716

}

647

if(sec_param == GNUTLS_SEC_PARAM_UNKNOWN){

648

/* Err on the side of caution */

649

sec_param = GNUTLS_SEC_PARAM_ULTRA;

717

uret = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, sec_param);

718

if(uret != 0){

719

mc->dh_bits = uret;

650

720

if(debug){

651

fprintf_plus(stderr, "Falling back to security parameter"

652

" \"%s\"\n",

721

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

722

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

653

723

safe_string(gnutls_sec_param_get_name

654

(sec_param)));

724

(sec_param)),

725

mc->dh_bits);

655

726

}

656

}

657

}

658

uret = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, sec_param);

659

if(uret != 0){

660

mc->dh_bits = uret;

661

if(debug){

662

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

663

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

727

} else {

728

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

729

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

664

730

safe_string(gnutls_sec_param_get_name

665

731

(sec_param)),

666

mc->dh_bits);

732

safer_gnutls_strerror(ret));

733

goto globalfail;

667

734

}

668

} else {

669

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

670

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

671

safe_string(gnutls_sec_param_get_name(sec_param)),

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,

672

743

safer_gnutls_strerror(ret));

673

744

goto globalfail;

674

745

}

675

} else if(debug){

676

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

677

mc->dh_bits);

678

}

679

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

680

if(ret != GNUTLS_E_SUCCESS){

681

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

682

" %s\n", mc->dh_bits, safer_gnutls_strerror(ret));

683

goto globalfail;

684

}

685

746

}

686

747

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

687

748

688

749

return 0;

690

751

globalfail:

691

752

692

753

gnutls_certificate_free_credentials(mc->cred);

693

gnutls_global_deinit();

694

754

gnutls_dh_params_deinit(mc->dh_params);

695

755

return -1;

696

756

}

748

808

/* ignore client certificate if any. */

749

809

gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);

750

810

751

gnutls_dh_set_prime_bits(*session, mc->dh_bits);

752

753

811

return 0;

754

812

}

755

813

757

815

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

758

816

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

759

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

760

1036

/* Called when a Mandos server is found */

761

1037

__attribute__((nonnull, warn_unused_result))

762

1038

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

773

1049

int retval = -1;

774

1050

gnutls_session_t session;

775

1051

int pf; /* Protocol family */

1052

bool route_added = false;

776

1053

777

1054

errno = 0;

778

1055

836

1113

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

837

1114

}

838

1115

839

tcp_sd = socket(pf, SOCK_STREAM, 0);

1116

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

840

1117

if(tcp_sd < 0){

841

1118

int e = errno;

842

1119

perror_plus("socket");

849

1126

goto mandos_end;

850

1127

}

851

1128

852

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

853

1129

if(af == AF_INET6){

854

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

855

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);

856

1133

} else { /* IPv4 */

857

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

858

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);

859

1137

}

860

1138

if(ret < 0 ){

861

1139

int e = errno;

931

1209

goto mandos_end;

932

1210

}

933

1211

934

if(af == AF_INET6){

935

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

936

sizeof(struct sockaddr_in6));

937

} else {

938

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

939

sizeof(struct sockaddr_in));

940

}

941

if(ret < 0){

942

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

943

int e = errno;

944

perror_plus("connect");

945

errno = e;

946

}

947

goto mandos_end;

948

}

949

950

if(quit_now){

951

errno = EINTR;

952

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;

953

1267

}

954

1268

955

1269

const char *out = mandos_protocol_version;

1138

1452

1139

1453

mandos_end:

1140

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

}

1141

1461

int e = errno;

1142

1462

free(decrypted_buffer);

1143

1463

free(buffer);

1144

1464

if(tcp_sd >= 0){

1145

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

1465

ret = close(tcp_sd);

1146

1466

}

1147

1467

if(ret == -1){

1148

1468

if(e == 0){

1303

1623

__attribute__((nonnull, warn_unused_result))

1304

1624

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

1305

1625

int ret;

1306

error_t ret_errno;

1626

int old_errno;

1307

1627

1308

1628

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

1309

1629

if(s < 0){

1310

ret_errno = errno;

1630

old_errno = errno;

1311

1631

perror_plus("socket");

1312

errno = ret_errno;

1632

errno = old_errno;

1313

1633

return false;

1314

1634

}

1315

strcpy(ifr->ifr_name, ifname);

1635

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

1636

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

1316

1637

ret = ioctl(s, SIOCGIFFLAGS, ifr);

1317

1638

if(ret == -1){

1318

1639

if(debug){

1319

ret_errno = errno;

1640

old_errno = errno;

1320

1641

perror_plus("ioctl SIOCGIFFLAGS");

1321

errno = ret_errno;

1642

errno = old_errno;

1322

1643

}

1323

1644

return false;

1324

1645

}

1569

1890

}

1570

1891

}

1571

1892

1572

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

1573

__attribute__((warn_unused_result))

1574

error_t raise_privileges(void){

1575

error_t old_errno = errno;

1576

error_t ret_errno = 0;

1577

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

1578

ret_errno = errno;

1579

}

1580

errno = old_errno;

1581

return ret_errno;

1582

}

1583

1584

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

1585

__attribute__((warn_unused_result))

1586

error_t raise_privileges_permanently(void){

1587

error_t old_errno = errno;

1588

error_t ret_errno = raise_privileges();

1589

if(ret_errno != 0){

1590

errno = old_errno;

1591

return ret_errno;

1592

}

1593

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

1594

ret_errno = errno;

1595

}

1596

errno = old_errno;

1597

return ret_errno;

1598

}

1599

1600

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

1601

__attribute__((warn_unused_result))

1602

error_t lower_privileges(void){

1603

error_t old_errno = errno;

1604

error_t ret_errno = 0;

1605

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

1606

ret_errno = errno;

1607

}

1608

errno = old_errno;

1609

return ret_errno;

1610

}

1611

1612

/* Lower privileges permanently */

1613

__attribute__((warn_unused_result))

1614

error_t lower_privileges_permanently(void){

1615

error_t old_errno = errno;

1616

error_t ret_errno = 0;

1617

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

1618

ret_errno = errno;

1619

}

1620

errno = old_errno;

1621

return ret_errno;

1622

}

1623

1624

1893

__attribute__((nonnull))

1625

1894

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

1626

1895

const float delay){

1627

1896

struct dirent **direntries = NULL;

1628

1897

if(hookdir_fd == -1){

1629

hookdir_fd = open(hookdir, O_RDONLY);

1898

hookdir_fd = open(hookdir, O_RDONLY | O_DIRECTORY | O_PATH

1899

| O_CLOEXEC);

1630

1900

if(hookdir_fd == -1){

1631

1901

if(errno == ENOENT){

1632

1902

if(debug){

1639

1909

return;

1640

1910

}

1641

1911

}

1642

#ifdef __GLIBC__

1643

#if __GLIBC_PREREQ(2, 15)

1644

1912

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

1645

1913

runnable_hook, alphasort);

1646

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

1647

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

1648

alphasort);

1649

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

1650

#else /* not __GLIBC__ */

1651

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

1652

alphasort);

1653

#endif /* not __GLIBC__ */

1654

1914

if(numhooks == -1){

1655

1915

perror_plus("scandir");

1656

1916

return;

1657

1917

}

1658

1918

struct dirent *direntry;

1659

1919

int ret;

1660

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

}

1661

1925

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

1662

1926

direntry = direntries[i];

1663

1927

if(debug){

1687

1951

perror_plus("setgroups");

1688

1952

_exit(EX_NOPERM);

1689

1953

}

1690

ret = dup2(devnull, STDIN_FILENO);

1691

if(ret == -1){

1692

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

1693

_exit(EX_OSERR);

1694

}

1695

ret = close(devnull);

1696

if(ret == -1){

1697

perror_plus("close");

1698

_exit(EX_OSERR);

1699

}

1700

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

1701

if(ret == -1){

1702

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

1703

_exit(EX_OSERR);

1704

}

1705

1954

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

1706

1955

if(ret == -1){

1707

1956

perror_plus("setenv");

1742

1991

_exit(EX_OSERR);

1743

1992

}

1744

1993

}

1745

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));

1746

1997

if(hook_fd == -1){

1747

1998

perror_plus("openat");

1748

1999

_exit(EXIT_FAILURE);

1749

2000

}

1750

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

2001

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

1751

2002

perror_plus("close");

1752

2003

_exit(EXIT_FAILURE);

1753

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

}

1754

2020

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

1755

2021

environ) == -1){

1756

2022

perror_plus("fexecve");

1796

2062

free(direntry);

1797

2063

}

1798

2064

free(direntries);

1799

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

2065

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

1800

2066

perror_plus("close");

1801

2067

} else {

1802

2068

hookdir_fd = -1;

1805

2071

}

1806

2072

1807

2073

__attribute__((nonnull, warn_unused_result))

1808

error_t bring_up_interface(const char *const interface,

1809

const float delay){

1810

error_t old_errno = errno;

2074

int bring_up_interface(const char *const interface,

2075

const float delay){

2076

int old_errno = errno;

1811

2077

int ret;

1812

2078

struct ifreq network;

1813

2079

unsigned int if_index = if_nametoindex(interface);

1823

2089

}

1824

2090

1825

2091

if(not interface_is_up(interface)){

1826

error_t ret_errno = 0, ioctl_errno = 0;

2092

int ret_errno = 0;

2093

int ioctl_errno = 0;

1827

2094

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

1828

2095

ret_errno = errno;

1829

2096

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

1842

2109

}

1843

2110

1844

2111

if(quit_now){

1845

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

2112

ret = close(sd);

1846

2113

if(ret == -1){

1847

2114

perror_plus("close");

1848

2115

}

1898

2165

}

1899

2166

1900

2167

/* Close the socket */

1901

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

2168

ret = close(sd);

1902

2169

if(ret == -1){

1903

2170

perror_plus("close");

1904

2171

}

1932

2199

}

1933

2200

1934

2201

__attribute__((nonnull, warn_unused_result))

1935

error_t take_down_interface(const char *const interface){

1936

error_t old_errno = errno;

2202

int take_down_interface(const char *const interface){

2203

int old_errno = errno;

1937

2204

struct ifreq network;

1938

2205

unsigned int if_index = if_nametoindex(interface);

1939

2206

if(if_index == 0){

1942

2209

return ENXIO;

1943

2210

}

1944

2211

if(interface_is_up(interface)){

1945

error_t ret_errno = 0, ioctl_errno = 0;

2212

int ret_errno = 0;

2213

int ioctl_errno = 0;

1946

2214

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

1947

2215

ret_errno = errno;

1948

2216

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

1986

2254

}

1987

2255

1988

2256

/* Close the socket */

1989

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

2257

int ret = close(sd);

1990

2258

if(ret == -1){

1991

2259

perror_plus("close");

1992

2260

}

2008

2276

2009

2277

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

2010

2278

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

2011

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

2012

"+CTYPE-OPENPGP:!RSA", .current_server = NULL,

2013

.interfaces = NULL, .interfaces_size = 0 };

2279

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

2280

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

2281

.current_server = NULL, .interfaces = NULL,

2282

.interfaces_size = 0 };

2014

2283

AvahiSServiceBrowser *sb = NULL;

2015

2284

error_t ret_errno;

2016

2285

int ret;

2025

2294

AvahiIfIndex if_index = AVAHI_IF_UNSPEC;

2026

2295

const char *seckey = PATHDIR "/" SECKEY;

2027

2296

const char *pubkey = PATHDIR "/" PUBKEY;

2297

const char *dh_params_file = NULL;

2028

2298

char *interfaces_hooks = NULL;

2029

2299

2030

2300

bool gnutls_initialized = false;

2083

2353

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

2084

2354

" Diffie-Hellman key exchange",

2085

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 },

2086

2361

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

2087

2362

.arg = "STRING",

2088

2363

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

2143

2418

}

2144

2419

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

2145

2420

break;

2421

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

2422

dh_params_file = arg;

2423

break;

2146

2424

case 130: /* --priority */

2147

2425

mc.priority = arg;

2148

2426

break;

2188

2466

.args_doc = "",

2189

2467

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

2190

2468

" passwords from a Mandos server" };

2191

ret = argp_parse(&argp, argc, argv,

2192

ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);

2193

switch(ret){

2469

ret_errno = argp_parse(&argp, argc, argv,

2470

ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);

2471

switch(ret_errno){

2194

2472

case 0:

2195

2473

break;

2196

2474

case ENOMEM:

2197

2475

default:

2198

errno = ret;

2476

errno = ret_errno;

2199

2477

perror_plus("argp_parse");

2200

2478

exitcode = EX_OSERR;

2201

2479

goto end;

2204

2482

goto end;

2205

2483

}

2206

2484

}

2207

2485

2208

2486

{

2209

2487

/* Work around Debian bug #633582:

2210

2488

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

2211

2489

2212

2490

/* Re-raise privileges */

2213

ret_errno = raise_privileges();

2214

if(ret_errno != 0){

2215

errno = ret_errno;

2491

ret = raise_privileges();

2492

if(ret != 0){

2493

errno = ret;

2216

2494

perror_plus("Failed to raise privileges");

2217

2495

} else {

2218

2496

struct stat st;

2234

2512

}

2235

2513

}

2236

2514

}

2237

TEMP_FAILURE_RETRY(close(seckey_fd));

2515

close(seckey_fd);

2238

2516

}

2239

2517

}

2240

2518

2241

2519

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

2242

2520

int pubkey_fd = open(pubkey, O_RDONLY);

2243

2521

if(pubkey_fd == -1){

2255

2533

}

2256

2534

}

2257

2535

}

2258

TEMP_FAILURE_RETRY(close(pubkey_fd));

2259

}

2260

}

2261

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

2262

2562

/* Lower privileges */

2263

ret_errno = lower_privileges();

2264

if(ret_errno != 0){

2265

errno = ret_errno;

2563

ret = lower_privileges();

2564

if(ret != 0){

2565

errno = ret;

2266

2566

perror_plus("Failed to lower privileges");

2267

2567

}

2268

2568

}

2438

2738

errno = bring_up_interface(interface, delay);

2439

2739

if(not interface_was_up){

2440

2740

if(errno != 0){

2441

perror_plus("Failed to bring up interface");

2741

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

2742

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

2442

2743

} else {

2443

2744

errno = argz_add(&interfaces_to_take_down,

2444

2745

&interfaces_to_take_down_size,

2467

2768

goto end;

2468

2769

}

2469

2770

2470

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

2771

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

2471

2772

if(ret == -1){

2472

2773

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

2473

2774

exitcode = EX_UNAVAILABLE;

2595

2896

2596

2897

/* Allocate a new server */

2597

2898

mc.server = avahi_server_new(avahi_simple_poll_get(simple_poll),

2598

&config, NULL, NULL, &ret_errno);

2899

&config, NULL, NULL, &ret);

2599

2900

2600

2901

/* Free the Avahi configuration data */

2601

2902

avahi_server_config_free(&config);

2604

2905

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

2605

2906

if(mc.server == NULL){

2606

2907

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

2607

avahi_strerror(ret_errno));

2908

avahi_strerror(ret));

2608

2909

exitcode = EX_UNAVAILABLE;

2609

2910

goto end;

2610

2911

}

2662

2963

2663

2964

if(gnutls_initialized){

2664

2965

gnutls_certificate_free_credentials(mc.cred);

2665

gnutls_global_deinit();

2666

2966

gnutls_dh_params_deinit(mc.dh_params);

2667

2967

}

2668

2968

2691

2991

2692

2992

/* Re-raise privileges */

2693

2993

{

2694

ret_errno = raise_privileges();

2695

if(ret_errno != 0){

2696

errno = ret_errno;

2994

ret = raise_privileges();

2995

if(ret != 0){

2996

errno = ret;

2697

2997

perror_plus("Failed to raise privileges");

2698

2998

} else {

2699

2999

2707

3007

while((interface=argz_next(interfaces_to_take_down,

2708

3008

interfaces_to_take_down_size,

2709

3009

interface))){

2710

ret_errno = take_down_interface(interface);

2711

if(ret_errno != 0){

2712

errno = ret_errno;

3010

ret = take_down_interface(interface);

3011

if(ret != 0){

3012

errno = ret;

2713

3013

perror_plus("Failed to take down interface");

2714

3014

}

2715

3015

}

2720

3020

}

2721

3021

}

2722

3022

2723

ret_errno = lower_privileges_permanently();

2724

if(ret_errno != 0){

2725

errno = ret_errno;

3023

ret = lower_privileges_permanently();

3024

if(ret != 0){

3025

errno = ret;

2726

3026

perror_plus("Failed to lower privileges permanently");

2727

3027

}

2728

3028

}

2730

3030

free(interfaces_to_take_down);

2731

3031

free(interfaces_hooks);

2732

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

2733

3089

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

2734

3090

if(tempdir != NULL){

2735

struct dirent **direntries = NULL;

2736

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

2737

O_NOFOLLOW));

2738

if(tempdir_fd == -1){

2739

perror_plus("open");

2740

} else {

2741

#ifdef __GLIBC__

2742

#if __GLIBC_PREREQ(2, 15)

2743

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

2744

notdotentries, alphasort);

2745

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

2746

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

2747

alphasort);

2748

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

2749

#else /* not __GLIBC__ */

2750

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

2751

alphasort);

2752

#endif /* not __GLIBC__ */

2753

if(numentries >= 0){

2754

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

2755

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

2756

if(ret == -1){

2757

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

2758

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

2759

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

2760

}

2761

free(direntries[i]);

2762

}

2763

2764

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

2765

free(direntries);

2766

if(numentries == -1){

2767

perror_plus("scandir");

2768

}

2769

ret = rmdir(tempdir);

2770

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

2771

perror_plus("rmdir");

2772

}

2773

}

2774

TEMP_FAILURE_RETRY(close(tempdir_fd));

2775

}

3091

clean_dir_at(-1, tempdir, 0);

2776

3092

}

2777

3093

2778

3094

if(quit_now){