/mandos/release : revision 237.7.304

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

493

return plaintext_length;

494

}

495

496

__attribute__((warn_unused_result, const))

497

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

498

if(str == NULL)

499

return "(unknown)";

500

return str;

501

}

502

496

503

__attribute__((warn_unused_result))

497

504

static const char *safer_gnutls_strerror(int value){

498

505

const char *ret = gnutls_strerror(value);

499

if(ret == NULL)

500

ret = "(unknown)";

501

return ret;

506

return safe_string(ret);

502

507

}

503

508

504

509

/* GnuTLS log function callback */

513

518

const char *seckeyfilename,

514

519

mandos_context *mc){

515

520

int ret;

521

unsigned int uret;

516

522

517

523

if(debug){

518

524

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

569

575

safer_gnutls_strerror(ret));

570

576

goto globalfail;

571

577

}

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;

585

while(true){

586

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

587

(size_t)buffer.size,

588

(size_t)buffer_capacity);

589

if(buffer_capacity == 0){

590

perror_plus("incbuffer");

591

free(buffer.data);

592

buffer.data = NULL;

593

break;

594

}

595

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

596

BUFFER_SIZE);

597

/* EOF */

598

if(bytes_read == 0){

599

break;

600

}

601

/* check bytes_read for failure */

602

if(bytes_read < 0){

603

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);

627

if(ret != GNUTLS_E_SUCCESS){

628

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

629

safer_gnutls_strerror(ret));

630

privkey = NULL;

631

}

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

}

644

}

645

}

646

}

647

if(sec_param == GNUTLS_SEC_PARAM_UNKNOWN){

648

/* Err on the side of caution */

649

sec_param = GNUTLS_SEC_PARAM_ULTRA;

650

if(debug){

651

fprintf_plus(stderr, "Falling back to security parameter"

652

" \"%s\"\n",

653

safe_string(gnutls_sec_param_get_name

654

(sec_param)));

655

}

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",

664

safe_string(gnutls_sec_param_get_name

665

(sec_param)),

666

mc->dh_bits);

667

}

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)),

672

safer_gnutls_strerror(ret));

673

goto globalfail;

674

}

675

} else if(debug){

676

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

677

mc->dh_bits);

678

}

572

679

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

573

680

if(ret != GNUTLS_E_SUCCESS){

574

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

575

safer_gnutls_strerror(ret));

681

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

682

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

576

683

goto globalfail;

577

684

}

578

685

650

757

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

651

758

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

652

759

653

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

654

__attribute__((warn_unused_result))

655

error_t raise_privileges(void){

656

error_t old_errno = errno;

657

error_t ret_errno = 0;

658

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

659

ret_errno = errno;

660

}

661

errno = old_errno;

662

return ret_errno;

663

}

664

665

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

666

__attribute__((warn_unused_result))

667

error_t raise_privileges_permanently(void){

668

error_t old_errno = errno;

669

error_t ret_errno = raise_privileges();

670

if(ret_errno != 0){

671

errno = old_errno;

672

return ret_errno;

673

}

674

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

675

ret_errno = errno;

676

}

677

errno = old_errno;

678

return ret_errno;

679

}

680

681

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

682

__attribute__((warn_unused_result))

683

error_t lower_privileges(void){

684

error_t old_errno = errno;

685

error_t ret_errno = 0;

686

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

687

ret_errno = errno;

688

}

689

errno = old_errno;

690

return ret_errno;

691

}

692

693

/* Lower privileges permanently */

694

__attribute__((warn_unused_result))

695

error_t lower_privileges_permanently(void){

696

error_t old_errno = errno;

697

error_t ret_errno = 0;

698

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

699

ret_errno = errno;

700

}

701

errno = old_errno;

702

return ret_errno;

703

}

704

705

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

706

__attribute__((nonnull, warn_unused_result))

707

static bool add_remove_local_route(const bool add,

708

const char *address,

709

AvahiIfIndex if_index){

710

int ret;

711

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

712

char add_arg[] = "add";

713

char remove_arg[] = "remove";

714

char *pluginhelperdir = getenv("MANDOSPLUGINHELPERDIR");

715

if(pluginhelperdir == NULL){

716

if(debug){

717

fprintf_plus(stderr, "MANDOSPLUGINHELPERDIR environment"

718

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

719

}

720

return false;

721

}

722

723

char interface[IF_NAMESIZE];

724

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

725

perror_plus("if_indextoname");

726

return false;

727

}

728

729

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

730

if(devnull == -1){

731

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

732

return false;

733

}

734

pid_t pid = fork();

735

if(pid == 0){

736

/* Child */

737

/* Raise privileges */

738

errno = raise_privileges_permanently();

739

if(errno != 0){

740

perror_plus("Failed to raise privileges");

741

/* _exit(EX_NOPERM); */

742

} else {

743

/* Set group */

744

errno = 0;

745

ret = setgid(0);

746

if(ret == -1){

747

perror_plus("setgid");

748

_exit(EX_NOPERM);

749

}

750

/* Reset supplementary groups */

751

errno = 0;

752

ret = setgroups(0, NULL);

753

if(ret == -1){

754

perror_plus("setgroups");

755

_exit(EX_NOPERM);

756

}

757

}

758

ret = dup2(devnull, STDIN_FILENO);

759

if(ret == -1){

760

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

761

_exit(EX_OSERR);

762

}

763

ret = close(devnull);

764

if(ret == -1){

765

perror_plus("close");

766

_exit(EX_OSERR);

767

}

768

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

769

if(ret == -1){

770

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

771

_exit(EX_OSERR);

772

}

773

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

774

O_RDONLY

775

| O_DIRECTORY

776

| O_PATH

777

| O_CLOEXEC));

778

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

779

helper, O_RDONLY));

780

TEMP_FAILURE_RETRY(close(helperdir_fd));

781

#ifdef __GNUC__

782

#pragma GCC diagnostic push

783

#pragma GCC diagnostic ignored "-Wcast-qual"

784

#endif

785

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

786

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

787

interface, NULL }, environ) == -1){

788

#ifdef __GNUC__

789

#pragma GCC diagnostic pop

790

#endif

791

perror_plus("fexecve");

792

_exit(EXIT_FAILURE);

793

}

794

}

795

if(pid == -1){

796

perror_plus("fork");

797

return false;

798

}

799

int status;

800

pid_t pret = -1;

801

errno = 0;

802

do {

803

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

804

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

805

int errno_raising = 0;

806

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

807

errno_raising = errno;

808

perror_plus("Failed to raise privileges in order to"

809

" kill helper program");

810

}

811

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

812

perror_plus("kill");

813

}

814

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

815

perror_plus("Failed to lower privileges after killing"

816

" helper program");

817

}

818

return false;

819

}

820

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

821

if(pret == -1){

822

perror_plus("waitpid");

823

return false;

824

}

825

if(WIFEXITED(status)){

826

if(WEXITSTATUS(status) != 0){

827

fprintf_plus(stderr, "Error: iprouteadddel exited"

828

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

829

return false;

830

}

831

return true;

832

}

833

if(WIFSIGNALED(status)){

834

fprintf_plus(stderr, "Error: iprouteadddel died by"

835

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

836

return false;

837

}

838

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

839

return false;

840

}

841

842

__attribute__((nonnull, warn_unused_result))

843

static bool add_local_route(const char *address,

844

AvahiIfIndex if_index){

845

return add_remove_local_route(true, address, if_index);

846

}

847

848

__attribute__((nonnull, warn_unused_result))

849

static bool remove_local_route(const char *address,

850

AvahiIfIndex if_index){

851

return add_remove_local_route(false, address, if_index);

852

}

853

854

760

/* Called when a Mandos server is found */

855

761

__attribute__((nonnull, warn_unused_result))

856

762

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

867

773

int retval = -1;

868

774

gnutls_session_t session;

869

775

int pf; /* Protocol family */

870

bool route_added = false;

871

776

872

777

errno = 0;

873

778

931

836

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

932

837

}

933

838

934

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

839

tcp_sd = socket(pf, SOCK_STREAM, 0);

935

840

if(tcp_sd < 0){

936

841

int e = errno;

937

842

perror_plus("socket");

1026

931

goto mandos_end;

1027

932

}

1028

933

1029

while(true){

1030

if(af == AF_INET6){

1031

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

1032

sizeof(struct sockaddr_in6));

1033

} else {

1034

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

1035

sizeof(struct sockaddr_in));

1036

}

1037

if(ret < 0){

1038

if(errno == ENETUNREACH

1039

and if_index != AVAHI_IF_UNSPEC

1040

and connect_to == NULL

1041

and not route_added and

1042

((af == AF_INET6 and not

1043

IN6_IS_ADDR_LINKLOCAL(&(((struct sockaddr_in6 *)

1044

&to)->sin6_addr)))

1045

or (af == AF_INET and

1046

/* Not a a IPv4LL address */

1047

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

1048

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

1049

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

1050

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

1051

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

1052

connect to a Mandos server announced by Avahi on a server

1053

host with a global address. Work around this by retrying

1054

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

1055

1056

Avahi bug reference:

1057

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

1058

https://bugs.debian.org/587961

1059

*/

1060

int e = errno;

1061

route_added = add_local_route(ip, if_index);

1062

if(route_added){

1063

continue;

1064

}

1065

errno = e;

1066

}

1067

if(errno != ECONNREFUSED or debug){

1068

int e = errno;

1069

perror_plus("connect");

1070

errno = e;

1071

}

1072

goto mandos_end;

1073

}

1074

1075

if(quit_now){

1076

errno = EINTR;

1077

goto mandos_end;

1078

}

1079

break;

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;

1080

953

}

1081

954

1082

955

const char *out = mandos_protocol_version;

1265

1138

1266

1139

mandos_end:

1267

1140

{

1268

if(route_added){

1269

if(not remove_local_route(ip, if_index)){

1270

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

1271

" interface %d", ip, if_index);

1272

}

1273

}

1274

1141

int e = errno;

1275

1142

free(decrypted_buffer);

1276

1143

free(buffer);

1702

1569

}

1703

1570

}

1704

1571

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

1705

1624

__attribute__((nonnull))

1706

1625

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

1707

1626

const float delay){

1708

1627

struct dirent **direntries = NULL;

1709

1628

if(hookdir_fd == -1){

1710

hookdir_fd = open(hookdir, O_RDONLY | O_DIRECTORY | O_PATH

1711

| O_CLOEXEC);

1629

hookdir_fd = open(hookdir, O_RDONLY);

1712

1630

if(hookdir_fd == -1){

1713

1631

if(errno == ENOENT){

1714

1632

if(debug){

1739

1657

}

1740

1658

struct dirent *direntry;

1741

1659

int ret;

1742

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

1743

if(devnull == -1){

1744

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

1745

return;

1746

}

1660

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

1747

1661

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

1748

1662

direntry = direntries[i];

1749

1663

if(debug){

1773

1687

perror_plus("setgroups");

1774

1688

_exit(EX_NOPERM);

1775

1689

}

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

}

1776

1705

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

1777

1706

if(ret == -1){

1778

1707

perror_plus("setenv");

1813

1742

_exit(EX_OSERR);

1814

1743

}

1815

1744

}

1816

int hook_fd = TEMP_FAILURE_RETRY(openat(hookdir_fd,

1817

direntry->d_name,

1818

O_RDONLY));

1745

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

1819

1746

if(hook_fd == -1){

1820

1747

perror_plus("openat");

1821

1748

_exit(EXIT_FAILURE);

1824

1751

perror_plus("close");

1825

1752

_exit(EXIT_FAILURE);

1826

1753

}

1827

ret = dup2(devnull, STDIN_FILENO);

1828

if(ret == -1){

1829

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

1830

_exit(EX_OSERR);

1831

}

1832

ret = close(devnull);

1833

if(ret == -1){

1834

perror_plus("close");

1835

_exit(EX_OSERR);

1836

}

1837

ret = dup2(STDERR_FILENO, STDOUT_FILENO);

1838

if(ret == -1){

1839

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

1840

_exit(EX_OSERR);

1841

}

1842

1754

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

1843

1755

environ) == -1){

1844

1756

perror_plus("fexecve");

2095

2007

}

2096

2008

2097

2009

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

2098

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

2010

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

2099

2011

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

2100

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

2012

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

2101

2013

.interfaces = NULL, .interfaces_size = 0 };

2102

2014

AvahiSServiceBrowser *sb = NULL;

2103

2015

error_t ret_errno;

2292

2204

goto end;

2293

2205

}

2294

2206

}

2295

2207

2296

2208

{

2297

2209

/* Work around Debian bug #633582:

2298

2210

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

2325

2237

TEMP_FAILURE_RETRY(close(seckey_fd));

2326

2238

}

2327

2239

}

2328

2240

2329

2241

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

2330

2242

int pubkey_fd = open(pubkey, O_RDONLY);

2331

2243

if(pubkey_fd == -1){

2346

2258

TEMP_FAILURE_RETRY(close(pubkey_fd));

2347

2259

}

2348

2260

}

2349

2261

2350

2262

/* Lower privileges */

2351

2263

ret_errno = lower_privileges();

2352

2264

if(ret_errno != 0){

2821

2733

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

2822

2734

if(tempdir != NULL){

2823

2735

struct dirent **direntries = NULL;

2824

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

2825

| O_NOFOLLOW

2826

| O_DIRECTORY

2827

| O_PATH));

2736

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

2737

O_NOFOLLOW));

2828

2738

if(tempdir_fd == -1){

2829

2739

perror_plus("open");

2830

2740

} else {