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Annotation of src/usr.bin/ssh/auth2-pubkey.c, Revision 1.31

1.31    ! djm         1: /* $OpenBSD: auth2-pubkey.c,v 1.30 2011/09/25 05:44:47 djm Exp $ */
1.1       markus      2: /*
                      3:  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
                      4:  *
                      5:  * Redistribution and use in source and binary forms, with or without
                      6:  * modification, are permitted provided that the following conditions
                      7:  * are met:
                      8:  * 1. Redistributions of source code must retain the above copyright
                      9:  *    notice, this list of conditions and the following disclaimer.
                     10:  * 2. Redistributions in binary form must reproduce the above copyright
                     11:  *    notice, this list of conditions and the following disclaimer in the
                     12:  *    documentation and/or other materials provided with the distribution.
                     13:  *
                     14:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
                     15:  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
                     16:  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
                     17:  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
                     18:  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
                     19:  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
                     20:  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
                     21:  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
                     22:  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
                     23:  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
                     24:  */
                     25:
1.10      stevesk    26:
                     27: #include <sys/types.h>
                     28: #include <sys/stat.h>
1.31    ! djm        29: #include <sys/wait.h>
1.13      stevesk    30:
1.31    ! djm        31: #include <errno.h>
1.16      djm        32: #include <fcntl.h>
1.31    ! djm        33: #include <paths.h>
1.13      stevesk    34: #include <pwd.h>
1.31    ! djm        35: #include <signal.h>
1.14      stevesk    36: #include <stdio.h>
1.15      deraadt    37: #include <stdarg.h>
1.20      djm        38: #include <string.h>
                     39: #include <time.h>
1.17      dtucker    40: #include <unistd.h>
1.1       markus     41:
1.15      deraadt    42: #include "xmalloc.h"
1.8       dtucker    43: #include "ssh.h"
1.1       markus     44: #include "ssh2.h"
                     45: #include "packet.h"
                     46: #include "buffer.h"
                     47: #include "log.h"
                     48: #include "servconf.h"
                     49: #include "compat.h"
1.15      deraadt    50: #include "key.h"
                     51: #include "hostfile.h"
1.1       markus     52: #include "auth.h"
                     53: #include "pathnames.h"
                     54: #include "uidswap.h"
                     55: #include "auth-options.h"
                     56: #include "canohost.h"
1.15      deraadt    57: #ifdef GSSAPI
                     58: #include "ssh-gss.h"
                     59: #endif
1.1       markus     60: #include "monitor_wrap.h"
1.9       dtucker    61: #include "misc.h"
1.21      djm        62: #include "authfile.h"
1.24      djm        63: #include "match.h"
1.1       markus     64:
                     65: /* import */
                     66: extern ServerOptions options;
                     67: extern u_char *session_id2;
1.4       markus     68: extern u_int session_id2_len;
1.1       markus     69:
1.2       markus     70: static int
1.1       markus     71: userauth_pubkey(Authctxt *authctxt)
                     72: {
                     73:        Buffer b;
                     74:        Key *key = NULL;
                     75:        char *pkalg;
                     76:        u_char *pkblob, *sig;
                     77:        u_int alen, blen, slen;
                     78:        int have_sig, pktype;
                     79:        int authenticated = 0;
                     80:
                     81:        if (!authctxt->valid) {
                     82:                debug2("userauth_pubkey: disabled because of invalid user");
                     83:                return 0;
                     84:        }
                     85:        have_sig = packet_get_char();
                     86:        if (datafellows & SSH_BUG_PKAUTH) {
                     87:                debug2("userauth_pubkey: SSH_BUG_PKAUTH");
                     88:                /* no explicit pkalg given */
                     89:                pkblob = packet_get_string(&blen);
                     90:                buffer_init(&b);
                     91:                buffer_append(&b, pkblob, blen);
                     92:                /* so we have to extract the pkalg from the pkblob */
                     93:                pkalg = buffer_get_string(&b, &alen);
                     94:                buffer_free(&b);
                     95:        } else {
                     96:                pkalg = packet_get_string(&alen);
                     97:                pkblob = packet_get_string(&blen);
                     98:        }
                     99:        pktype = key_type_from_name(pkalg);
                    100:        if (pktype == KEY_UNSPEC) {
                    101:                /* this is perfectly legal */
1.3       itojun    102:                logit("userauth_pubkey: unsupported public key algorithm: %s",
1.1       markus    103:                    pkalg);
                    104:                goto done;
                    105:        }
                    106:        key = key_from_blob(pkblob, blen);
                    107:        if (key == NULL) {
                    108:                error("userauth_pubkey: cannot decode key: %s", pkalg);
                    109:                goto done;
                    110:        }
                    111:        if (key->type != pktype) {
                    112:                error("userauth_pubkey: type mismatch for decoded key "
                    113:                    "(received %d, expected %d)", key->type, pktype);
                    114:                goto done;
                    115:        }
                    116:        if (have_sig) {
                    117:                sig = packet_get_string(&slen);
                    118:                packet_check_eom();
                    119:                buffer_init(&b);
                    120:                if (datafellows & SSH_OLD_SESSIONID) {
                    121:                        buffer_append(&b, session_id2, session_id2_len);
                    122:                } else {
                    123:                        buffer_put_string(&b, session_id2, session_id2_len);
                    124:                }
                    125:                /* reconstruct packet */
                    126:                buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
                    127:                buffer_put_cstring(&b, authctxt->user);
                    128:                buffer_put_cstring(&b,
                    129:                    datafellows & SSH_BUG_PKSERVICE ?
                    130:                    "ssh-userauth" :
                    131:                    authctxt->service);
                    132:                if (datafellows & SSH_BUG_PKAUTH) {
                    133:                        buffer_put_char(&b, have_sig);
                    134:                } else {
                    135:                        buffer_put_cstring(&b, "publickey");
                    136:                        buffer_put_char(&b, have_sig);
                    137:                        buffer_put_cstring(&b, pkalg);
                    138:                }
                    139:                buffer_put_string(&b, pkblob, blen);
                    140: #ifdef DEBUG_PK
                    141:                buffer_dump(&b);
                    142: #endif
                    143:                /* test for correct signature */
                    144:                authenticated = 0;
                    145:                if (PRIVSEP(user_key_allowed(authctxt->pw, key)) &&
                    146:                    PRIVSEP(key_verify(key, sig, slen, buffer_ptr(&b),
1.6       markus    147:                    buffer_len(&b))) == 1)
1.1       markus    148:                        authenticated = 1;
1.6       markus    149:                buffer_free(&b);
1.1       markus    150:                xfree(sig);
                    151:        } else {
                    152:                debug("test whether pkalg/pkblob are acceptable");
                    153:                packet_check_eom();
                    154:
                    155:                /* XXX fake reply and always send PK_OK ? */
                    156:                /*
                    157:                 * XXX this allows testing whether a user is allowed
                    158:                 * to login: if you happen to have a valid pubkey this
                    159:                 * message is sent. the message is NEVER sent at all
                    160:                 * if a user is not allowed to login. is this an
                    161:                 * issue? -markus
                    162:                 */
                    163:                if (PRIVSEP(user_key_allowed(authctxt->pw, key))) {
                    164:                        packet_start(SSH2_MSG_USERAUTH_PK_OK);
                    165:                        packet_put_string(pkalg, alen);
                    166:                        packet_put_string(pkblob, blen);
                    167:                        packet_send();
                    168:                        packet_write_wait();
                    169:                        authctxt->postponed = 1;
                    170:                }
                    171:        }
                    172:        if (authenticated != 1)
                    173:                auth_clear_options();
                    174: done:
                    175:        debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg);
                    176:        if (key != NULL)
                    177:                key_free(key);
                    178:        xfree(pkalg);
                    179:        xfree(pkblob);
                    180:        return authenticated;
                    181: }
                    182:
1.24      djm       183: static int
                    184: match_principals_option(const char *principal_list, struct KeyCert *cert)
                    185: {
                    186:        char *result;
                    187:        u_int i;
                    188:
                    189:        /* XXX percent_expand() sequences for authorized_principals? */
                    190:
                    191:        for (i = 0; i < cert->nprincipals; i++) {
                    192:                if ((result = match_list(cert->principals[i],
                    193:                    principal_list, NULL)) != NULL) {
                    194:                        debug3("matched principal from key options \"%.100s\"",
                    195:                            result);
                    196:                        xfree(result);
                    197:                        return 1;
                    198:                }
                    199:        }
                    200:        return 0;
                    201: }
                    202:
                    203: static int
1.26      djm       204: match_principals_file(char *file, struct passwd *pw, struct KeyCert *cert)
1.24      djm       205: {
                    206:        FILE *f;
1.26      djm       207:        char line[SSH_MAX_PUBKEY_BYTES], *cp, *ep, *line_opts;
1.24      djm       208:        u_long linenum = 0;
                    209:        u_int i;
                    210:
                    211:        temporarily_use_uid(pw);
                    212:        debug("trying authorized principals file %s", file);
                    213:        if ((f = auth_openprincipals(file, pw, options.strict_modes)) == NULL) {
                    214:                restore_uid();
                    215:                return 0;
                    216:        }
                    217:        while (read_keyfile_line(f, file, line, sizeof(line), &linenum) != -1) {
1.26      djm       218:                /* Skip leading whitespace. */
1.24      djm       219:                for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
                    220:                        ;
1.26      djm       221:                /* Skip blank and comment lines. */
                    222:                if ((ep = strchr(cp, '#')) != NULL)
                    223:                        *ep = '\0';
                    224:                if (!*cp || *cp == '\n')
1.24      djm       225:                        continue;
1.26      djm       226:                /* Trim trailing whitespace. */
                    227:                ep = cp + strlen(cp) - 1;
                    228:                while (ep > cp && (*ep == '\n' || *ep == ' ' || *ep == '\t'))
                    229:                        *ep-- = '\0';
                    230:                /*
                    231:                 * If the line has internal whitespace then assume it has
                    232:                 * key options.
                    233:                 */
                    234:                line_opts = NULL;
                    235:                if ((ep = strrchr(cp, ' ')) != NULL ||
                    236:                    (ep = strrchr(cp, '\t')) != NULL) {
                    237:                        for (; *ep == ' ' || *ep == '\t'; ep++)
1.27      deraadt   238:                                ;
1.26      djm       239:                        line_opts = cp;
                    240:                        cp = ep;
                    241:                }
1.24      djm       242:                for (i = 0; i < cert->nprincipals; i++) {
                    243:                        if (strcmp(cp, cert->principals[i]) == 0) {
1.30      djm       244:                                debug3("matched principal \"%.100s\" "
                    245:                                    "from file \"%s\" on line %lu",
1.31    ! djm       246:                                    cert->principals[i], file, linenum);
1.26      djm       247:                                if (auth_parse_options(pw, line_opts,
                    248:                                    file, linenum) != 1)
                    249:                                        continue;
1.24      djm       250:                                fclose(f);
                    251:                                restore_uid();
                    252:                                return 1;
                    253:                        }
                    254:                }
                    255:        }
                    256:        fclose(f);
                    257:        restore_uid();
                    258:        return 0;
1.31    ! djm       259: }
1.24      djm       260:
1.31    ! djm       261: /*
        !           262:  * Checks whether key is allowed in authorized_keys-format file,
        !           263:  * returns 1 if the key is allowed or 0 otherwise.
        !           264:  */
1.1       markus    265: static int
1.31    ! djm       266: check_authkeys_file(FILE *f, char *file, Key* key, struct passwd *pw)
1.1       markus    267: {
1.8       dtucker   268:        char line[SSH_MAX_PUBKEY_BYTES];
1.20      djm       269:        const char *reason;
1.18      dtucker   270:        int found_key = 0;
1.1       markus    271:        u_long linenum = 0;
                    272:        Key *found;
                    273:        char *fp;
                    274:
                    275:        found_key = 0;
1.20      djm       276:        found = key_new(key_is_cert(key) ? KEY_UNSPEC : key->type);
1.1       markus    277:
1.8       dtucker   278:        while (read_keyfile_line(f, file, line, sizeof(line), &linenum) != -1) {
1.7       avsm      279:                char *cp, *key_options = NULL;
1.8       dtucker   280:
1.20      djm       281:                auth_clear_options();
                    282:
1.1       markus    283:                /* Skip leading whitespace, empty and comment lines. */
                    284:                for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
                    285:                        ;
                    286:                if (!*cp || *cp == '\n' || *cp == '#')
                    287:                        continue;
                    288:
                    289:                if (key_read(found, &cp) != 1) {
                    290:                        /* no key?  check if there are options for this key */
                    291:                        int quoted = 0;
                    292:                        debug2("user_key_allowed: check options: '%s'", cp);
1.7       avsm      293:                        key_options = cp;
1.1       markus    294:                        for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
                    295:                                if (*cp == '\\' && cp[1] == '"')
                    296:                                        cp++;   /* Skip both */
                    297:                                else if (*cp == '"')
                    298:                                        quoted = !quoted;
                    299:                        }
                    300:                        /* Skip remaining whitespace. */
                    301:                        for (; *cp == ' ' || *cp == '\t'; cp++)
                    302:                                ;
                    303:                        if (key_read(found, &cp) != 1) {
                    304:                                debug2("user_key_allowed: advance: '%s'", cp);
                    305:                                /* still no key?  advance to next line*/
                    306:                                continue;
                    307:                        }
                    308:                }
1.23      djm       309:                if (key_is_cert(key)) {
1.25      djm       310:                        if (!key_equal(found, key->cert->signature_key))
                    311:                                continue;
                    312:                        if (auth_parse_options(pw, key_options, file,
                    313:                            linenum) != 1)
                    314:                                continue;
1.20      djm       315:                        if (!key_is_cert_authority)
                    316:                                continue;
                    317:                        fp = key_fingerprint(found, SSH_FP_MD5,
                    318:                            SSH_FP_HEX);
1.22      djm       319:                        debug("matching CA found: file %s, line %lu, %s %s",
                    320:                            file, linenum, key_type(found), fp);
1.24      djm       321:                        /*
                    322:                         * If the user has specified a list of principals as
                    323:                         * a key option, then prefer that list to matching
                    324:                         * their username in the certificate principals list.
                    325:                         */
                    326:                        if (authorized_principals != NULL &&
                    327:                            !match_principals_option(authorized_principals,
                    328:                            key->cert)) {
                    329:                                reason = "Certificate does not contain an "
                    330:                                    "authorized principal";
                    331:  fail_reason:
1.22      djm       332:                                xfree(fp);
1.20      djm       333:                                error("%s", reason);
                    334:                                auth_debug_add("%s", reason);
                    335:                                continue;
                    336:                        }
1.24      djm       337:                        if (key_cert_check_authority(key, 0, 0,
                    338:                            authorized_principals == NULL ? pw->pw_name : NULL,
                    339:                            &reason) != 0)
                    340:                                goto fail_reason;
1.23      djm       341:                        if (auth_cert_options(key, pw) != 0) {
1.22      djm       342:                                xfree(fp);
1.20      djm       343:                                continue;
1.22      djm       344:                        }
                    345:                        verbose("Accepted certificate ID \"%s\" "
                    346:                            "signed by %s CA %s via %s", key->cert->key_id,
                    347:                            key_type(found), fp, file);
                    348:                        xfree(fp);
1.20      djm       349:                        found_key = 1;
                    350:                        break;
1.25      djm       351:                } else if (key_equal(found, key)) {
                    352:                        if (auth_parse_options(pw, key_options, file,
                    353:                            linenum) != 1)
                    354:                                continue;
                    355:                        if (key_is_cert_authority)
                    356:                                continue;
1.1       markus    357:                        found_key = 1;
                    358:                        debug("matching key found: file %s, line %lu",
                    359:                            file, linenum);
                    360:                        fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
                    361:                        verbose("Found matching %s key: %s",
                    362:                            key_type(found), fp);
                    363:                        xfree(fp);
                    364:                        break;
                    365:                }
                    366:        }
                    367:        key_free(found);
                    368:        if (!found_key)
                    369:                debug2("key not found");
                    370:        return found_key;
                    371: }
                    372:
1.21      djm       373: /* Authenticate a certificate key against TrustedUserCAKeys */
                    374: static int
                    375: user_cert_trusted_ca(struct passwd *pw, Key *key)
                    376: {
1.24      djm       377:        char *ca_fp, *principals_file = NULL;
1.21      djm       378:        const char *reason;
                    379:        int ret = 0;
                    380:
                    381:        if (!key_is_cert(key) || options.trusted_user_ca_keys == NULL)
                    382:                return 0;
                    383:
1.22      djm       384:        ca_fp = key_fingerprint(key->cert->signature_key,
                    385:            SSH_FP_MD5, SSH_FP_HEX);
1.21      djm       386:
                    387:        if (key_in_file(key->cert->signature_key,
                    388:            options.trusted_user_ca_keys, 1) != 1) {
                    389:                debug2("%s: CA %s %s is not listed in %s", __func__,
                    390:                    key_type(key->cert->signature_key), ca_fp,
                    391:                    options.trusted_user_ca_keys);
                    392:                goto out;
                    393:        }
1.24      djm       394:        /*
                    395:         * If AuthorizedPrincipals is in use, then compare the certificate
                    396:         * principals against the names in that file rather than matching
                    397:         * against the username.
                    398:         */
                    399:        if ((principals_file = authorized_principals_file(pw)) != NULL) {
                    400:                if (!match_principals_file(principals_file, pw, key->cert)) {
                    401:                        reason = "Certificate does not contain an "
                    402:                            "authorized principal";
                    403:  fail_reason:
                    404:                        error("%s", reason);
                    405:                        auth_debug_add("%s", reason);
                    406:                        goto out;
                    407:                }
1.21      djm       408:        }
1.24      djm       409:        if (key_cert_check_authority(key, 0, 1,
                    410:            principals_file == NULL ? pw->pw_name : NULL, &reason) != 0)
                    411:                goto fail_reason;
1.23      djm       412:        if (auth_cert_options(key, pw) != 0)
1.21      djm       413:                goto out;
                    414:
1.22      djm       415:        verbose("Accepted certificate ID \"%s\" signed by %s CA %s via %s",
                    416:            key->cert->key_id, key_type(key->cert->signature_key), ca_fp,
                    417:            options.trusted_user_ca_keys);
1.21      djm       418:        ret = 1;
                    419:
                    420:  out:
1.24      djm       421:        if (principals_file != NULL)
                    422:                xfree(principals_file);
1.21      djm       423:        if (ca_fp != NULL)
                    424:                xfree(ca_fp);
                    425:        return ret;
                    426: }
                    427:
1.31    ! djm       428: /*
        !           429:  * Checks whether key is allowed in file.
        !           430:  * returns 1 if the key is allowed or 0 otherwise.
        !           431:  */
        !           432: static int
        !           433: user_key_allowed2(struct passwd *pw, Key *key, char *file)
        !           434: {
        !           435:        FILE *f;
        !           436:        int found_key = 0;
        !           437:
        !           438:        /* Temporarily use the user's uid. */
        !           439:        temporarily_use_uid(pw);
        !           440:
        !           441:        debug("trying public key file %s", file);
        !           442:        if ((f = auth_openkeyfile(file, pw, options.strict_modes)) != NULL) {
        !           443:                found_key = check_authkeys_file(f, file, key, pw);
        !           444:                fclose(f);
        !           445:        }
        !           446:
        !           447:        restore_uid();
        !           448:        return found_key;
        !           449: }
        !           450:
        !           451: /*
        !           452:  * Checks whether key is allowed in output of command.
        !           453:  * returns 1 if the key is allowed or 0 otherwise.
        !           454:  */
        !           455: static int
        !           456: user_key_command_allowed2(struct passwd *user_pw, Key *key)
        !           457: {
        !           458:        FILE *f;
        !           459:        int ok, found_key = 0;
        !           460:        struct passwd *pw;
        !           461:        struct stat st;
        !           462:        int status, devnull, p[2], i;
        !           463:        pid_t pid;
        !           464:        char errmsg[512];
        !           465:
        !           466:        if (options.authorized_keys_command == NULL ||
        !           467:            options.authorized_keys_command[0] != '/')
        !           468:                return 0;
        !           469:
        !           470:        /* If no user specified to run commands the default to target user */
        !           471:        if (options.authorized_keys_command_user == NULL)
        !           472:                pw = user_pw;
        !           473:        else {
        !           474:                pw = getpwnam(options.authorized_keys_command_user);
        !           475:                if (pw == NULL) {
        !           476:                        error("AuthorizedKeyCommandUser \"%s\" not found: %s",
        !           477:                            options.authorized_keys_command, strerror(errno));
        !           478:                        return 0;
        !           479:                }
        !           480:        }
        !           481:
        !           482:        temporarily_use_uid(pw);
        !           483:
        !           484:        if (stat(options.authorized_keys_command, &st) < 0) {
        !           485:                error("Could not stat AuthorizedKeysCommand \"%s\": %s",
        !           486:                    options.authorized_keys_command, strerror(errno));
        !           487:                goto out;
        !           488:        }
        !           489:        if (auth_secure_path(options.authorized_keys_command, &st, NULL, 0,
        !           490:            errmsg, sizeof(errmsg)) != 0) {
        !           491:                error("Unsafe AuthorizedKeysCommand: %s", errmsg);
        !           492:                goto out;
        !           493:        }
        !           494:
        !           495:        if (pipe(p) != 0) {
        !           496:                error("%s: pipe: %s", __func__, strerror(errno));
        !           497:                goto out;
        !           498:        }
        !           499:
        !           500:        debug3("Running AuthorizedKeysCommand: \"%s\" as \"%s\"",
        !           501:            options.authorized_keys_command, pw->pw_name);
        !           502:
        !           503:        /*
        !           504:         * Don't want to call this in the child, where it can fatal() and
        !           505:         * run cleanup_exit() code.
        !           506:         */
        !           507:        restore_uid();
        !           508:
        !           509:        switch ((pid = fork())) {
        !           510:        case -1: /* error */
        !           511:                error("%s: fork: %s", __func__, strerror(errno));
        !           512:                close(p[0]);
        !           513:                close(p[1]);
        !           514:                return 0;
        !           515:        case 0: /* child */
        !           516:                for (i = 0; i < NSIG; i++)
        !           517:                        signal(i, SIG_DFL);
        !           518:
        !           519:                /* Don't use permanently_set_uid() here to avoid fatal() */
        !           520:                if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0) {
        !           521:                        error("setresgid %u: %s", (u_int)pw->pw_gid,
        !           522:                            strerror(errno));
        !           523:                        _exit(1);
        !           524:                }
        !           525:                if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0) {
        !           526:                        error("setresuid %u: %s", (u_int)pw->pw_uid,
        !           527:                            strerror(errno));
        !           528:                        _exit(1);
        !           529:                }
        !           530:
        !           531:                close(p[0]);
        !           532:                if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
        !           533:                        error("%s: open %s: %s", __func__, _PATH_DEVNULL,
        !           534:                            strerror(errno));
        !           535:                        _exit(1);
        !           536:                }
        !           537:                if (dup2(devnull, STDIN_FILENO) == -1 ||
        !           538:                    dup2(p[1], STDOUT_FILENO) == -1 ||
        !           539:                    dup2(devnull, STDERR_FILENO) == -1) {
        !           540:                        error("%s: dup2: %s", __func__, strerror(errno));
        !           541:                        _exit(1);
        !           542:                }
        !           543:                closefrom(STDERR_FILENO + 1);
        !           544:
        !           545:                execl(options.authorized_keys_command,
        !           546:                    options.authorized_keys_command, pw->pw_name, NULL);
        !           547:
        !           548:                error("AuthorizedKeysCommand %s exec failed: %s",
        !           549:                    options.authorized_keys_command, strerror(errno));
        !           550:                _exit(127);
        !           551:        default: /* parent */
        !           552:                break;
        !           553:        }
        !           554:
        !           555:        temporarily_use_uid(pw);
        !           556:
        !           557:        close(p[1]);
        !           558:        if ((f = fdopen(p[0], "r")) == NULL) {
        !           559:                error("%s: fdopen: %s", __func__, strerror(errno));
        !           560:                close(p[0]);
        !           561:                /* Don't leave zombie child */
        !           562:                kill(pid, SIGTERM);
        !           563:                while (waitpid(pid, NULL, 0) == -1 && errno == EINTR)
        !           564:                        ;
        !           565:                goto out;
        !           566:        }
        !           567:        ok = check_authkeys_file(f, options.authorized_keys_command, key, pw);
        !           568:        fclose(f);
        !           569:
        !           570:        while (waitpid(pid, &status, 0) == -1) {
        !           571:                if (errno != EINTR) {
        !           572:                        error("%s: waitpid: %s", __func__, strerror(errno));
        !           573:                        goto out;
        !           574:                }
        !           575:        }
        !           576:        if (WIFSIGNALED(status)) {
        !           577:                error("AuthorizedKeysCommand %s exited on signal %d",
        !           578:                    options.authorized_keys_command, WTERMSIG(status));
        !           579:                goto out;
        !           580:        } else if (WEXITSTATUS(status) != 0) {
        !           581:                error("AuthorizedKeysCommand %s returned status %d",
        !           582:                    options.authorized_keys_command, WEXITSTATUS(status));
        !           583:                goto out;
        !           584:        }
        !           585:        found_key = ok;
        !           586:  out:
        !           587:        restore_uid();
        !           588:        return found_key;
        !           589: }
        !           590:
        !           591: /*
        !           592:  * Check whether key authenticates and authorises the user.
        !           593:  */
1.1       markus    594: int
                    595: user_key_allowed(struct passwd *pw, Key *key)
                    596: {
1.29      djm       597:        u_int success, i;
1.1       markus    598:        char *file;
1.21      djm       599:
                    600:        if (auth_key_is_revoked(key))
                    601:                return 0;
                    602:        if (key_is_cert(key) && auth_key_is_revoked(key->cert->signature_key))
                    603:                return 0;
                    604:
                    605:        success = user_cert_trusted_ca(pw, key);
                    606:        if (success)
                    607:                return success;
1.1       markus    608:
1.31    ! djm       609:        success = user_key_command_allowed2(pw, key);
        !           610:        if (success > 0)
        !           611:                return success;
        !           612:
1.29      djm       613:        for (i = 0; !success && i < options.num_authkeys_files; i++) {
1.31    ! djm       614:
        !           615:                if (strcasecmp(options.authorized_keys_files[i], "none") == 0)
        !           616:                        continue;
1.29      djm       617:                file = expand_authorized_keys(
                    618:                    options.authorized_keys_files[i], pw);
1.31    ! djm       619:
1.29      djm       620:                success = user_key_allowed2(pw, key, file);
                    621:                xfree(file);
                    622:        }
1.1       markus    623:
                    624:        return success;
                    625: }
1.2       markus    626:
                    627: Authmethod method_pubkey = {
                    628:        "publickey",
                    629:        userauth_pubkey,
                    630:        &options.pubkey_authentication
                    631: };