src/mod_auth_kerb.c

   1 /*
   2  * Daniel Kouril <kouril@users.sourceforge.org>
   3  *
   4  * Source and Documentation can be found at:
   5  * http://modauthkerb.sourceforge.net/
   6  *
   7  * Based on work by
   8  *   James E. Robinson, III <james@ncstate.net>
   9  *   Daniel Henninger <daniel@ncsu.edu>
  10  */
  11
  12 /* ====================================================================
  13  * The Apache Software License, Version 1.1
  14  *
  15  * Copyright (c) 2000-2003 The Apache Software Foundation.  All rights
  16  * reserved.
  17  *
  18  * Redistribution and use in source and binary forms, with or without
  19  * modification, are permitted provided that the following conditions
  20  * are met:
  21  *
  22  * 1. Redistributions of source code must retain the above copyright
  23  *    notice, this list of conditions and the following disclaimer.
  24  *
  25  * 2. Redistributions in binary form must reproduce the above copyright
  26  *    notice, this list of conditions and the following disclaimer in
  27  *    the documentation and/or other materials provided with the
  28  *    distribution.
  29  *
  30  * 3. The end-user documentation included with the redistribution,
  31  *    if any, must include the following acknowledgment:
  32  *       "This product includes software developed by the
  33  *        Apache Software Foundation (http://www.apache.org/)."
  34  *    Alternately, this acknowledgment may appear in the software itself,
  35  *    if and wherever such third-party acknowledgments normally appear.
  36  *
  37  * 4. The names "Apache" and "Apache Software Foundation" must
  38  *    not be used to endorse or promote products derived from this
  39  *    software without prior written permission. For written
  40  *    permission, please contact apache@apache.org.
  41  *
  42  * 5. Products derived from this software may not be called "Apache",
  43  *    nor may "Apache" appear in their name, without prior written
  44  *    permission of the Apache Software Foundation.
  45  *
  46  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
  47  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  48  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  49  * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
  50  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  51  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  52  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  53  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  54  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  55  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  56  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  57  * SUCH DAMAGE.
  58  * ====================================================================
  59  *
  60  * This software consists of voluntary contributions made by many
  61  * individuals on behalf of the Apache Software Foundation.  For more
  62  * information on the Apache Software Foundation, please see
  63  * <http://www.apache.org/>.
  64  *
  65  * Portions of this software are based upon public domain software
  66  * originally written at the National Center for Supercomputing Applications,
  67  * University of Illinois, Urbana-Champaign.
  68  */
  69
  70 #ident "$Id$"
  71
  72 #ifndef APXS1
  73 #include "ap_compat.h"
  74 #include "apr_strings.h"
  75 #endif
  76 #include "httpd.h"
  77 #include "http_config.h"
  78 #include "http_core.h"
  79 #include "http_log.h"
  80 #include "http_protocol.h"
  81 #include "http_request.h"
  82
  83 #ifdef KRB5
  84 #include <krb5.h>
  85 #include <gssapi.h>
  86 #ifndef HEIMDAL
  87 #  include <gssapi_generic.h>
  88 #  define GSS_C_NT_USER_NAME gss_nt_user_name
  89 #  define GSS_C_NT_HOSTBASED_SERVICE gss_nt_service_name
  90 #  define krb5_get_err_text(context,code) error_message(code)
  91 #endif
  92 #endif /* KRB5 */
  93
  94 #ifdef KRB4
  95 /*Prevent warning about closesocket redefinition (Apache's ap_config.h and
  96  * MIT Kerberos' port-sockets.h both define it as close) */
  97 #ifdef closesocket
  98 #  undef closesocket
  99 #endif
 100 #include <krb.h>
 101 #endif /* KRB4 */
 102
 103 #ifdef APXS1
 104 module auth_kerb_module;
 105 #else
 106 module AP_MODULE_DECLARE_DATA auth_kerb_module;
 107 #endif
 108
 109 /***************************************************************************
 110  Macros To Ease Compatibility
 111  ***************************************************************************/
 112 #ifdef APXS1
 113 #define MK_POOL pool
 114 #define MK_TABLE_GET ap_table_get
 115 #define MK_TABLE_SET ap_table_set
 116 #define MK_TABLE_TYPE table
 117 #define MK_PSTRDUP ap_pstrdup
 118 #define MK_USER r->connection->user
 119 #define MK_AUTH_TYPE r->connection->ap_auth_type
 120 #define MK_ARRAY_HEADER array_header
 121 #else
 122 #define MK_POOL apr_pool_t
 123 #define MK_TABLE_GET apr_table_get
 124 #define MK_TABLE_SET apr_table_set
 125 #define MK_TABLE_TYPE apr_table_t
 126 #define MK_PSTRDUP apr_pstrdup
 127 #define MK_USER r->user
 128 #define MK_AUTH_TYPE r->ap_auth_type
 129 #define MK_ARRAY_HEADER apr_array_header_t
 130 #endif /* APXS1 */
 131
 132
 133 /***************************************************************************
 134  Auth Configuration Structure
 135  ***************************************************************************/
 136 typedef struct {
 137         char *krb_auth_realms;
 138         int krb_save_credentials;
 139 #ifdef KRB5
 140         char *krb_5_keytab;
 141         int krb_method_gssapi;
 142         int krb_method_k5pass;
 143 #endif
 144 #ifdef KRB4
 145         char *krb_4_srvtab;
 146         int krb_method_k4pass;
 147 #endif
 148 } kerb_auth_config;
 149
 150 static const char*
 151 krb5_save_realms(cmd_parms *cmd, kerb_auth_config *sec, char *arg);
 152
 153 #ifdef APXS1
 154 #define command(name, func, var, type, usage)           \
 155   { name, func,                                         \
 156     (void*)XtOffsetOf(kerb_auth_config, var),           \
 157     OR_AUTHCFG, type, usage }
 158 #else
 159 #define command(name, func, var, type, usage)           \
 160   AP_INIT_ ## type (name, func,                         \
 161         (void*)APR_XtOffsetOf(kerb_auth_config, var),   \
 162         OR_AUTHCFG, usage)
 163 #endif
 164
 165 static const command_rec kerb_auth_cmds[] = {
 166    command("KrbAuthRealms", krb5_save_realms, krb_auth_realms,
 167      RAW_ARGS, "Realms to attempt authentication against (can be multiple)."),
 168
 169    command("KrbAuthRealm", krb5_save_realms, krb_auth_realms,
 170      RAW_ARGS, "Alias for KrbAuthRealms."),
 171
 172    command("KrbSaveCredentials", ap_set_flag_slot, krb_save_credentials,
 173      FLAG, "Save and store credentials/tickets retrieved during auth."),
 174
 175 #ifdef KRB5
 176    command("Krb5Keytab", ap_set_file_slot, krb_5_keytab,
 177      TAKE1, "Location of Kerberos V5 keytab file."),
 178
 179    command("KrbMethodNegotiate", ap_set_flag_slot, krb_method_gssapi,
 180      FLAG, "Enable Negotiate authentication method."),
 181
 182    command("KrbMethodK5Pass", ap_set_flag_slot, krb_method_k5pass,
 183      FLAG, "Enable Kerberos V5 password authentication."),
 184 #endif
 185
 186 #ifdef KRB4
 187    command("Krb4Srvtab", ap_set_file_slot, krb_4_srvtab,
 188      TAKE1, "Location of Kerberos V4 srvtab file."),
 189
 190    command("KrbMethodK4Pass", ap_set_flag_slot, krb_method_k4pass,
 191      FLAG, "Enable Kerberos V4 password authentication."),
 192 #endif
 193
 194    { NULL }
 195 };
 196
 197 #ifdef KRB5
 198 typedef struct {
 199    gss_ctx_id_t context;
 200    gss_cred_id_t server_creds;
 201 } gss_connection_t;
 202
 203 static gss_connection_t *gss_connection = NULL;
 204 #endif
 205
 206
 207 /***************************************************************************
 208  Auth Configuration Initialization
 209  ***************************************************************************/
 210 static void *kerb_dir_create_config(MK_POOL *p, char *d)
 211 {
 212         kerb_auth_config *rec;
 213
 214         rec = (kerb_auth_config *) ap_pcalloc(p, sizeof(kerb_auth_config));
 215 #ifdef KRB5
 216         ((kerb_auth_config *)rec)->krb_method_k5pass = 1;
 217         ((kerb_auth_config *)rec)->krb_method_gssapi = 1;
 218 #endif
 219 #ifdef KRB4
 220         ((kerb_auth_config *)rec)->krb_method_k4pass = 1;
 221 #endif
 222         return rec;
 223 }
 224
 225 static const char*
 226 krb5_save_realms(cmd_parms *cmd, kerb_auth_config *sec, char *arg)
 227 {
 228    sec->krb_auth_realms= ap_pstrdup(cmd->pool, arg);
 229    return NULL;
 230 }
 231
 232 void log_rerror(const char *file, int line, int level, int status,
 233                 const request_rec *r, const char *fmt, ...)
 234 {
 235    char errstr[1024];
 236    va_list ap;
 237
 238    va_start(ap, fmt);
 239    vsnprintf(errstr, sizeof(errstr), fmt, ap);
 240    va_end(ap);
 241
 242 #ifdef APXS1
 243    ap_log_rerror(file, line, level, r, "%s", errstr);
 244 #else
 245    ap_log_rerror(file, line, level, status, r, "%s", errstr);
 246 #endif
 247 }
 248
 249 #ifdef KRB4
 250 /***************************************************************************
 251  Username/Password Validation for Krb4
 252  ***************************************************************************/
 253 static int
 254 verify_krb4_user(request_rec *r, char *name, char *instance, char *realm,
 255                  char *password, char *linstance, char *srvtab)
 256 {
 257    int ret;
 258    char *phost;
 259    unsigned long addr;
 260    struct hostent *hp;
 261    const char *hostname;
 262    KTEXT_ST ticket;
 263    AUTH_DAT authdata;
 264    char lrealm[REALM_SZ];
 265
 266    ret = krb_get_pw_in_tkt(name, instance, realm, "krbtgt", realm,
 267                            DEFAULT_TKT_LIFE, password);
 268    if (ret)
 269       /* log(krb_err_txt[ret]) */
 270       return ret;
 271
 272    hostname = ap_get_server_name(r);
 273
 274    hp = gethostbyname(hostname);
 275    if (hp == NULL) {
 276       dest_tkt();
 277       return h_errno;
 278    }
 279    memcpy(&addr, hp->h_addr, sizeof(addr));
 280
 281    phost = krb_get_phost((char *)hostname);
 282
 283    krb_get_lrealm(lrealm, 1);
 284
 285    ret = krb_mk_req(&ticket, linstance, phost, lrealm, 0);
 286    if (ret) {
 287       dest_tkt();
 288       return ret;
 289    }
 290
 291    ret = krb_rd_req(&ticket, linstance, phost, addr, &authdata, srvtab);
 292    if (ret)
 293       dest_tkt();
 294
 295    return ret;
 296 }
 297
 298 static int
 299 krb4_cache_cleanup(void *data)
 300 {
 301    char *tkt_file = (char *) data;
 302
 303    krb_set_tkt_string(tkt_file);
 304    dest_tkt();
 305    return OK;
 306 }
 307
 308 static int
 309 authenticate_user_krb4pwd(request_rec *r,
 310                           kerb_auth_config *conf,
 311                           const char *auth_line)
 312 {
 313    int ret;
 314    const char *sent_pw;
 315    const char *sent_name;
 316    char *sent_instance;
 317    char tkt_file[32];
 318    char *tkt_file_p = NULL;
 319    int fd;
 320    const char *realms;
 321    const char *realm;
 322    char *user;
 323    char lrealm[REALM_SZ];
 324
 325    sent_pw = ap_pbase64decode(r->pool, auth_line);
 326    sent_name = ap_getword (r->pool, &sent_pw, ':');
 327
 328    /* do not allow user to override realm setting of server */
 329    if (strchr(sent_name, '@')) {
 330       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 331                  "specifying realm in user name is prohibited");
 332       return HTTP_UNAUTHORIZED;
 333    }
 334
 335    sent_instance = strchr(sent_name, '.');
 336    if (sent_instance)
 337       *sent_instance++ = '\0';
 338
 339    snprintf(tkt_file, sizeof(tkt_file), "/tmp/apache_tkt_XXXXXX");
 340    fd = mkstemp(tkt_file);
 341    if (fd < 0) {
 342       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 343                  "Cannot create krb4 ccache: mkstemp() failed: %s",
 344                  strerror(errno));
 345       return HTTP_INTERNAL_SERVER_ERROR;
 346    }
 347
 348    tkt_file_p = ap_pstrdup(r->pool, tkt_file);
 349    ap_register_cleanup(r->pool, tkt_file_p,
 350                        krb4_cache_cleanup, ap_null_cleanup);
 351
 352    krb_set_tkt_string(tkt_file);
 353
 354    realms = conf->krb_auth_realms;
 355    do {
 356       memset(lrealm, 0, sizeof(lrealm));
 357       realm = NULL;
 358       if (realms)
 359          realm = ap_getword_white(r->pool, &realms);
 360
 361       if (realm == NULL) {
 362          ret = krb_get_lrealm(lrealm, 1);
 363          realm = lrealm;
 364       }
 365       if (realm == NULL || *realm == '\0')
 366          break;
 367
 368       ret = verify_krb4_user(r, (char *)sent_name,
 369                              (sent_instance) ? sent_instance : "",
 370                              (char *)realm, (char *)sent_pw, "khttp",
 371                              conf->krb_4_srvtab);
 372       if (ret == 0)
 373          break;
 374    } while (realms && *realms);
 375
 376    if (ret) {
 377       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 378                  "Verifying krb4 password failed (%d)", ret);
 379       ret = HTTP_UNAUTHORIZED;
 380       goto end;
 381    }
 382
 383    user = ap_pstrdup(r->pool, sent_name);
 384    if (sent_instance)
 385       user = ap_pstrcat(r->pool, user, ".", sent_instance, NULL);
 386    user = ap_pstrcat(r->pool, user, "@", realm, NULL);
 387
 388    MK_USER = user;
 389    MK_AUTH_TYPE = "Basic";
 390    ap_table_setn(r->subprocess_env, "KRBTKFILE", tkt_file_p);
 391
 392    if (!conf->krb_save_credentials)
 393       krb4_cache_cleanup(tkt_file);
 394
 395 end:
 396    if (ret)
 397       krb4_cache_cleanup(tkt_file);
 398    close(fd);
 399    tf_close();
 400
 401    return ret;
 402 }
 403 #endif /* KRB4 */
 404
 405 #ifdef KRB5
 406 /***************************************************************************
 407  Username/Password Validation for Krb5
 408  ***************************************************************************/
 409 /* Inspired by krb5_verify_user from Heimdal */
 410 static krb5_error_code
 411 verify_krb5_user(request_rec *r, krb5_context context, krb5_principal principal,
 412                  krb5_ccache ccache, const char *password, const char *service,
 413                  krb5_keytab keytab)
 414 {
 415    krb5_creds creds;
 416    krb5_principal server = NULL;
 417    krb5_error_code ret;
 418    krb5_verify_init_creds_opt opt;
 419
 420    memset(&creds, 0, sizeof(creds));
 421
 422    ret = krb5_get_init_creds_password(context, &creds, principal,
 423                                       (char *)password, krb5_prompter_posix,
 424                                       NULL, 0, NULL, NULL);
 425    if (ret)
 426       return ret;
 427
 428    ret = krb5_sname_to_principal(context, ap_get_server_name(r), service,
 429                                  KRB5_NT_SRV_HST, &server);
 430    if (ret)
 431       goto end;
 432
 433    krb5_verify_init_creds_opt_init(&opt);
 434    krb5_verify_init_creds_opt_set_ap_req_nofail(&opt, 1);
 435
 436    ret = krb5_verify_init_creds(context, &creds, server, keytab, NULL, &opt);
 437    if (ret)
 438       goto end;
 439
 440    if (ccache) {
 441       ret = krb5_cc_initialize(context, ccache, principal);
 442       if (ret == 0)
 443          ret = krb5_cc_store_cred(context, ccache, &creds);
 444    }
 445
 446 end:
 447    krb5_free_cred_contents(context, &creds);
 448    if (server)
 449       krb5_free_principal(context, server);
 450    return ret;
 451 }
 452
 453 static int
 454 krb5_cache_cleanup(void *data)
 455 {
 456    krb5_context context;
 457    krb5_ccache  cache;
 458    krb5_error_code problem;
 459    char *cache_name = (char *) data;
 460
 461    problem = krb5_init_context(&context);
 462    if (problem) {
 463       /* ap_log_error(APLOG_MARK, APLOG_ERR, 0, NULL, "krb5_init_context() failed"); */
 464       return HTTP_INTERNAL_SERVER_ERROR;
 465    }
 466
 467    problem = krb5_cc_resolve(context, cache_name, &cache);
 468    if (problem) {
 469       /* log_error(APLOG_MARK, APLOG_ERR, 0, NULL,
 470                 "krb5_cc_resolve() failed (%s: %s)",
 471                 cache_name, krb5_get_err_text(context, problem)); */
 472       return HTTP_INTERNAL_SERVER_ERROR;
 473    }
 474
 475    krb5_cc_destroy(context, cache);
 476    krb5_free_context(context);
 477    return OK;
 478 }
 479
 480 static int
 481 create_krb5_ccache(krb5_context kcontext,
 482                    request_rec *r,
 483                    kerb_auth_config *conf,
 484                    krb5_principal princ,
 485                    krb5_ccache *ccache)
 486 {
 487    char *ccname;
 488    krb5_error_code problem;
 489    int ret;
 490    krb5_ccache tmp_ccache = NULL;
 491
 492 #ifdef HEIMDAL
 493    problem = krb5_cc_gen_new(kcontext, &krb5_fcc_ops, &tmp_ccache);
 494 #else
 495    problem = krb5_fcc_generate_new(kcontext, &tmp_ccache);
 496    /* krb5_fcc_generate_new() doesn't set KRB5_TC_OPENCLOSE, which makes
 497       krb5_cc_initialize() fail */
 498    krb5_fcc_set_flags(kcontext, tmp_ccache, KRB5_TC_OPENCLOSE);
 499 #endif
 500    if (problem) {
 501       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 502                  "Cannot create file for new krb5 ccache: %s",
 503                  krb5_get_err_text(kcontext, problem));
 504       ret = HTTP_INTERNAL_SERVER_ERROR;
 505       goto end;
 506    }
 507
 508    ccname = ap_pstrdup(r->pool, krb5_cc_get_name(kcontext, tmp_ccache));
 509
 510    problem = krb5_cc_initialize(kcontext, tmp_ccache, princ);
 511    if (problem) {
 512       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 513                  "Cannot initialize krb5 ccache %s: krb5_cc_initialize() failed: %s",
 514                  ccname, krb5_get_err_text(kcontext, problem));
 515       ret = HTTP_INTERNAL_SERVER_ERROR;
 516       goto end;
 517    }
 518
 519    ap_table_setn(r->subprocess_env, "KRB5CCNAME", ccname);
 520    ap_register_cleanup(r->pool, ccname,
 521                        krb5_cache_cleanup, ap_null_cleanup);
 522
 523    *ccache = tmp_ccache;
 524    tmp_ccache = NULL;
 525
 526    ret = OK;
 527
 528 end:
 529    if (tmp_ccache)
 530       krb5_cc_destroy(kcontext, tmp_ccache);
 531
 532    return ret;
 533 }
 534
 535 static int
 536 store_krb5_creds(krb5_context kcontext,
 537                  request_rec *r,
 538                  kerb_auth_config *conf,
 539                  krb5_ccache delegated_cred)
 540 {
 541    char errstr[1024];
 542    krb5_error_code problem;
 543    krb5_principal princ;
 544    krb5_ccache ccache;
 545    int ret;
 546
 547    problem = krb5_cc_get_principal(kcontext, delegated_cred, &princ);
 548    if (problem) {
 549       snprintf(errstr, sizeof(errstr), "krb5_cc_get_principal() failed: %s",
 550                krb5_get_err_text(kcontext, problem));
 551       return HTTP_INTERNAL_SERVER_ERROR;
 552    }
 553
 554    ret = create_krb5_ccache(kcontext, r, conf, princ, &ccache);
 555    if (ret) {
 556       krb5_free_principal(kcontext, princ);
 557       return ret;
 558    }
 559
 560 #ifdef HEIMDAL
 561    problem = krb5_cc_copy_cache(kcontext, delegated_cred, ccache);
 562 #else
 563    problem = krb5_cc_copy_creds(kcontext, delegated_cred, ccache);
 564 #endif
 565    krb5_free_principal(kcontext, princ);
 566    if (problem) {
 567       snprintf(errstr, sizeof(errstr), "Failed to store credentials: %s",
 568                krb5_get_err_text(kcontext, problem));
 569       krb5_cc_destroy(kcontext, ccache);
 570       return HTTP_INTERNAL_SERVER_ERROR;
 571    }
 572
 573    krb5_cc_close(kcontext, ccache);
 574    return OK;
 575 }
 576
 577
 578 int authenticate_user_krb5pwd(request_rec *r,
 579                               kerb_auth_config *conf,
 580                               const char *auth_line)
 581 {
 582    const char      *sent_pw = NULL;
 583    const char      *sent_name = NULL;
 584    const char      *realms = NULL;
 585    krb5_context    kcontext = NULL;
 586    krb5_error_code code;
 587    krb5_principal  client = NULL;
 588    krb5_ccache     ccache = NULL;
 589    krb5_keytab     keytab = NULL;
 590    int             ret;
 591    char *name = NULL;
 592
 593    code = krb5_init_context(&kcontext);
 594    if (code) {
 595       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 596                  "Cannot initialize Kerberos5 context (%d)", code);
 597       return HTTP_INTERNAL_SERVER_ERROR;
 598    }
 599
 600    sent_pw = ap_pbase64decode(r->pool, auth_line);
 601    sent_name = ap_getword (r->pool, &sent_pw, ':');
 602    /* do not allow user to override realm setting of server */
 603    if (strchr(sent_name, '@')) {
 604       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 605                  "specifying realm in user name is prohibited");
 606       ret = HTTP_UNAUTHORIZED;
 607       goto end;
 608    }
 609
 610 #ifdef HEIMDAL
 611    code = krb5_cc_gen_new(kcontext, &krb5_mcc_ops, &ccache);
 612 #else
 613    code = krb5_mcc_generate_new(kcontext, &ccache);
 614 #endif
 615    if (code) {
 616       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 617                  "Cannot generate new ccache: %s",
 618                  krb5_get_err_text(kcontext, code));
 619       ret = HTTP_INTERNAL_SERVER_ERROR;
 620       goto end;
 621    }
 622
 623    if (conf->krb_5_keytab)
 624       krb5_kt_resolve(kcontext, conf->krb_5_keytab, &keytab);
 625       /* setenv("KRB5_KTNAME", conf->krb_5_keytab, 1); */
 626
 627    realms = conf->krb_auth_realms;
 628    do {
 629       if (realms && (code = krb5_set_default_realm(kcontext,
 630                                            ap_getword_white(r->pool, &realms))))
 631          continue;
 632
 633       if (client) {
 634          krb5_free_principal(kcontext, client);
 635          client = NULL;
 636       }
 637       code = krb5_parse_name(kcontext, sent_name, &client);
 638       if (code)
 639          continue;
 640
 641       code = verify_krb5_user(r, kcontext, client, ccache, sent_pw, "khttp",
 642                               keytab);
 643       if (code == 0)
 644          break;
 645
 646       /* ap_getword_white() used above shifts the parameter, so it's not
 647          needed to touch the realms variable */
 648    } while (realms && *realms);
 649
 650    memset((char *)sent_pw, 0, strlen(sent_pw));
 651
 652    if (code) {
 653       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 654                  "Verifying krb5 password failed: %s",
 655                  krb5_get_err_text(kcontext, code));
 656       ret = HTTP_UNAUTHORIZED;
 657       goto end;
 658    }
 659
 660    code = krb5_unparse_name(kcontext, client, &name);
 661    if (code) {
 662       log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "krb5_unparse_name() failed: %s",
 663                  krb5_get_err_text(kcontext, code));
 664       ret = HTTP_UNAUTHORIZED;
 665       goto end;
 666    }
 667    MK_USER = ap_pstrdup (r->pool, name);
 668    MK_AUTH_TYPE = "Basic";
 669    free(name);
 670
 671    if (conf->krb_save_credentials)
 672       store_krb5_creds(kcontext, r, conf, ccache);
 673
 674    ret = OK;
 675
 676 end:
 677    if (client)
 678       krb5_free_principal(kcontext, client);
 679    if (ccache)
 680       krb5_cc_destroy(kcontext, ccache);
 681    if (keytab)
 682       krb5_kt_close(kcontext, keytab);
 683    krb5_free_context(kcontext);
 684
 685    return ret;
 686 }
 687
 688 /*********************************************************************
 689  * GSSAPI Authentication
 690  ********************************************************************/
 691
 692 static const char *
 693 get_gss_error(MK_POOL *p, OM_uint32 error_status, char *prefix)
 694 {
 695    OM_uint32 maj_stat, min_stat;
 696    OM_uint32 msg_ctx = 0;
 697    gss_buffer_desc status_string;
 698    char buf[1024];
 699    size_t len;
 700
 701    snprintf(buf, sizeof(buf), "%s", prefix);
 702    len = strlen(buf);
 703    do {
 704       maj_stat = gss_display_status (&min_stat,
 705                                      error_status,
 706                                      GSS_C_MECH_CODE,
 707                                      GSS_C_NO_OID,
 708                                      &msg_ctx,
 709                                      &status_string);
 710       if (sizeof(buf) > len + status_string.length + 1) {
 711          sprintf(buf+len, ": %s", (char*) status_string.value);
 712          len += status_string.length;
 713       }
 714       gss_release_buffer(&min_stat, &status_string);
 715    } while (!GSS_ERROR(maj_stat) && msg_ctx != 0);
 716
 717    return (ap_pstrdup(p, buf));
 718 }
 719
 720 static int
 721 cleanup_gss_connection(void *data)
 722 {
 723    OM_uint32 minor_status;
 724    gss_connection_t *gss_conn = (gss_connection_t *)data;
 725
 726    if (data == NULL)
 727       return OK;
 728    if (gss_conn->context != GSS_C_NO_CONTEXT)
 729       gss_delete_sec_context(&minor_status, &gss_conn->context,
 730                              GSS_C_NO_BUFFER);
 731    if (gss_conn->server_creds != GSS_C_NO_CREDENTIAL)
 732       gss_release_cred(&minor_status, &gss_conn->server_creds);
 733
 734    gss_connection = NULL;
 735
 736    return OK;
 737 }
 738
 739 static int
 740 store_gss_creds(request_rec *r, kerb_auth_config *conf, char *princ_name,
 741                 gss_cred_id_t delegated_cred)
 742 {
 743    OM_uint32 maj_stat, min_stat;
 744    krb5_principal princ = NULL;
 745    krb5_ccache ccache = NULL;
 746    krb5_error_code problem;
 747    krb5_context context;
 748    int ret = HTTP_INTERNAL_SERVER_ERROR;
 749
 750    problem = krb5_init_context(&context);
 751    if (problem) {
 752       log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "Cannot initialize krb5 context");
 753       return HTTP_INTERNAL_SERVER_ERROR;
 754    }
 755
 756    problem = krb5_parse_name(context, princ_name, &princ);
 757    if (problem) {
 758       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 759          "Cannot parse delegated username (%s)", krb5_get_err_text(context, problem));
 760       goto end;
 761    }
 762
 763    problem = create_krb5_ccache(context, r, conf, princ, &ccache);
 764    if (problem) {
 765       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 766          "Cannot create krb5 ccache (%s)", krb5_get_err_text(context, problem));
 767       goto end;
 768    }
 769
 770    maj_stat = gss_krb5_copy_ccache(&min_stat, delegated_cred, ccache);
 771    if (GSS_ERROR(maj_stat)) {
 772       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 773          "Cannot store delegated credential (%s)",
 774          get_gss_error(r->pool, min_stat, "gss_krb5_copy_ccache"));
 775       goto end;
 776    }
 777
 778    krb5_cc_close(context, ccache);
 779    ccache = NULL;
 780    ret = 0;
 781
 782 end:
 783    if (princ)
 784       krb5_free_principal(context, princ);
 785    if (ccache)
 786       krb5_cc_destroy(context, ccache);
 787    krb5_free_context(context);
 788    return ret;
 789 }
 790
 791 static int
 792 get_gss_creds(request_rec *r,
 793               kerb_auth_config *conf,
 794               gss_cred_id_t *server_creds)
 795 {
 796    gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
 797    OM_uint32 major_status, minor_status, minor_status2;
 798    gss_name_t server_name = GSS_C_NO_NAME;
 799    char buf[1024];
 800
 801    snprintf(buf, sizeof(buf), "%s/%s", "khttp", ap_get_server_name(r));
 802
 803    input_token.value = buf;
 804    input_token.length = strlen(buf) + 1;
 805
 806    major_status = gss_import_name(&minor_status, &input_token,
 807                                   GSS_C_NT_USER_NAME,
 808                                   &server_name);
 809    if (GSS_ERROR(major_status)) {
 810       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 811                  "%s", get_gss_error(r->pool, minor_status,
 812                  "gss_import_name() failed"));
 813       return HTTP_INTERNAL_SERVER_ERROR;
 814    }
 815
 816    major_status = gss_acquire_cred(&minor_status, server_name, GSS_C_INDEFINITE,
 817                                    GSS_C_NO_OID_SET, GSS_C_ACCEPT,
 818                                    server_creds, NULL, NULL);
 819    gss_release_name(&minor_status2, &server_name);
 820    if (GSS_ERROR(major_status)) {
 821       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 822                  "%s", get_gss_error(r->pool, minor_status,
 823                                      "gss_acquire_cred() failed"));
 824       return HTTP_INTERNAL_SERVER_ERROR;
 825    }
 826
 827    return 0;
 828 }
 829
 830 static int
 831 authenticate_user_gss(request_rec *r,
 832                       kerb_auth_config *conf,
 833                       const char *auth_line)
 834 {
 835   OM_uint32 major_status, minor_status, minor_status2;
 836   gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
 837   gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER;
 838   const char *auth_param = NULL;
 839   int ret;
 840   gss_name_t client_name = GSS_C_NO_NAME;
 841   gss_cred_id_t delegated_cred = GSS_C_NO_CREDENTIAL;
 842   static int initial_return = HTTP_UNAUTHORIZED;
 843
 844   /* needed to work around replay caches */
 845   if (!ap_is_initial_req(r))
 846      return initial_return;
 847   initial_return = HTTP_UNAUTHORIZED;
 848
 849   if (gss_connection == NULL) {
 850      gss_connection = ap_pcalloc(r->connection->pool, sizeof(*gss_connection));
 851      if (gss_connection == NULL) {
 852         log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 853                    "ap_pcalloc() failed (not enough memory)");
 854         ret = HTTP_INTERNAL_SERVER_ERROR;
 855         goto end;
 856      }
 857      memset(gss_connection, 0, sizeof(*gss_connection));
 858      ap_register_cleanup(r->connection->pool, gss_connection, cleanup_gss_connection, ap_null_cleanup);
 859   }
 860
 861   if (conf->krb_5_keytab)
 862      setenv("KRB5_KTNAME", conf->krb_5_keytab, 1);
 863
 864   if (gss_connection->server_creds == GSS_C_NO_CREDENTIAL) {
 865      ret = get_gss_creds(r, conf, &gss_connection->server_creds);
 866      if (ret)
 867         goto end;
 868   }
 869
 870   /* ap_getword() shifts parameter */
 871   auth_param = ap_getword_white(r->pool, &auth_line);
 872   if (auth_param == NULL) {
 873      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 874                 "No Authorization parameter in request from client");
 875      ret = HTTP_UNAUTHORIZED;
 876      goto end;
 877   }
 878
 879   input_token.length = ap_base64decode_len(auth_param) + 1;
 880   input_token.value = ap_pcalloc(r->connection->pool, input_token.length);
 881   if (input_token.value == NULL) {
 882      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 883                 "ap_pcalloc() failed (not enough memory)");
 884      ret = HTTP_INTERNAL_SERVER_ERROR;
 885      goto end;
 886   }
 887   input_token.length = ap_base64decode(input_token.value, auth_param);
 888
 889   major_status = gss_accept_sec_context(&minor_status,
 890                                         &gss_connection->context,
 891                                         gss_connection->server_creds,
 892                                         &input_token,
 893                                         GSS_C_NO_CHANNEL_BINDINGS,
 894                                         &client_name,
 895                                         NULL,
 896                                         &output_token,
 897                                         NULL,
 898                                         NULL,
 899                                         &delegated_cred);
 900   if (output_token.length) {
 901      char *token = NULL;
 902      size_t len;
 903
 904      len = ap_base64encode_len(output_token.length) + 1;
 905      token = ap_pcalloc(r->connection->pool, len + 1);
 906      if (token == NULL) {
 907         log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 908                    "ap_pcalloc() failed (not enough memory)");
 909         ret = HTTP_INTERNAL_SERVER_ERROR;
 910         gss_release_buffer(&minor_status2, &output_token);
 911         goto end;
 912      }
 913      ap_base64encode(token, output_token.value, output_token.length);
 914      token[len] = '\0';
 915      ap_table_set(r->err_headers_out, "WWW-Authenticate",
 916                   ap_pstrcat(r->pool, "GSS-Negotiate ", token, NULL));
 917      gss_release_buffer(&minor_status2, &output_token);
 918   }
 919
 920   if (GSS_ERROR(major_status)) {
 921      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 922                 "%s", get_gss_error(r->pool, minor_status,
 923                                     "gss_accept_sec_context() failed"));
 924      ret = HTTP_UNAUTHORIZED;
 925      goto end;
 926   }
 927
 928   if (major_status & GSS_S_CONTINUE_NEEDED) {
 929      /* Some GSSAPI mechanism (eg GSI from Globus) may require multiple
 930       * iterations to establish authentication */
 931      ret = HTTP_UNAUTHORIZED;
 932      goto end;
 933   }
 934
 935   major_status = gss_display_name(&minor_status, client_name, &output_token, NULL);
 936   gss_release_name(&minor_status, &client_name);
 937   if (GSS_ERROR(major_status)) {
 938     log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 939                "%s", get_gss_error(r->pool, minor_status,
 940                                    "gss_export_name() failed"));
 941     ret = HTTP_INTERNAL_SERVER_ERROR;
 942     goto end;
 943   }
 944
 945   MK_AUTH_TYPE = "Negotiate";
 946   MK_USER = ap_pstrdup(r->pool, output_token.value);
 947
 948   if (conf->krb_save_credentials && delegated_cred != GSS_C_NO_CREDENTIAL)
 949      store_gss_creds(r, conf, (char *)output_token.value, delegated_cred);
 950
 951   gss_release_buffer(&minor_status, &output_token);
 952
 953   ret = OK;
 954
 955 end:
 956   if (delegated_cred)
 957      gss_release_cred(&minor_status, &delegated_cred);
 958
 959   if (output_token.length)
 960      gss_release_buffer(&minor_status, &output_token);
 961
 962   if (client_name != GSS_C_NO_NAME)
 963      gss_release_name(&minor_status, &client_name);
 964
 965   cleanup_gss_connection(gss_connection);
 966
 967   initial_return = ret;
 968   return ret;
 969 }
 970 #endif /* KRB5 */
 971
 972
 973 static void
 974 note_kerb_auth_failure(request_rec *r, const kerb_auth_config *conf,
 975                        int use_krb4, int use_krb5)
 976 {
 977    const char *auth_name = NULL;
 978    int set_basic = 0;
 979
 980    /* get the user realm specified in .htaccess */
 981    auth_name = ap_auth_name(r);
 982
 983    /* XXX should the WWW-Authenticate header be cleared first? */
 984 #ifdef KRB5
 985    if (use_krb5 && conf->krb_method_gssapi)
 986       ap_table_add(r->err_headers_out, "WWW-Authenticate", "GSS-Negotiate ");
 987    if (use_krb5 && conf->krb_method_k5pass) {
 988       ap_table_add(r->err_headers_out, "WWW-Authenticate",
 989                    ap_pstrcat(r->pool, "Basic realm=\"", auth_name, "\"", NULL));
 990       set_basic = 1;
 991    }
 992 #endif
 993
 994 #ifdef KRB4
 995    if (use_krb4 && conf->krb_method_k4pass && !set_basic)
 996       ap_table_add(r->err_headers_out, "WWW-Authenticate",
 997                    ap_pstrcat(r->pool, "Basic realm=\"", auth_name, "\"", NULL));
 998 #endif
 999 }
1000
1001 int kerb_authenticate_user(request_rec *r)
1002 {
1003    kerb_auth_config *conf =
1004       (kerb_auth_config *) ap_get_module_config(r->per_dir_config,
1005                                                 &auth_kerb_module);
1006    const char *auth_type = NULL;
1007    const char *auth_line = NULL;
1008    const char *type = NULL;
1009    int use_krb5 = 0, use_krb4 = 0;
1010    int ret;
1011
1012    /* get the type specified in .htaccess */
1013    type = ap_auth_type(r);
1014
1015    if (type && strcasecmp(type, "Kerberos") == 0)
1016       use_krb5 = use_krb4 = 1;
1017    else if(type && strcasecmp(type, "KerberosV5") == 0)
1018       use_krb4 = 0;
1019    else if(type && strcasecmp(type, "KerberosV4") == 0)
1020       use_krb5 = 0;
1021    else
1022       return DECLINED;
1023
1024    /* get what the user sent us in the HTTP header */
1025    auth_line = MK_TABLE_GET(r->headers_in, "Authorization");
1026    if (!auth_line) {
1027       note_kerb_auth_failure(r, conf, use_krb4, use_krb5);
1028       return HTTP_UNAUTHORIZED;
1029    }
1030    auth_type = ap_getword_white(r->pool, &auth_line);
1031
1032    ret = HTTP_UNAUTHORIZED;
1033
1034 #ifdef KRB5
1035    if (use_krb5 && conf->krb_method_gssapi &&
1036        strcasecmp(auth_type, "GSS-Negotiate") == 0) {
1037       ret = authenticate_user_gss(r, conf, auth_line);
1038    } else if (use_krb5 && conf->krb_method_k5pass &&
1039               strcasecmp(auth_type, "Basic") == 0) {
1040        ret = authenticate_user_krb5pwd(r, conf, auth_line);
1041    }
1042 #endif
1043
1044 #ifdef KRB4
1045    if (ret == HTTP_UNAUTHORIZED && use_krb4 && conf->krb_method_k4pass &&
1046        strcasecmp(auth_type, "Basic") == 0)
1047       ret = authenticate_user_krb4pwd(r, conf, auth_line);
1048 #endif
1049
1050    if (ret == HTTP_UNAUTHORIZED)
1051       note_kerb_auth_failure(r, conf, use_krb4, use_krb5);
1052
1053    return ret;
1054 }
1055
1056
1057 /***************************************************************************
1058  Module Setup/Configuration
1059  ***************************************************************************/
1060 #ifdef APXS1
1061 module MODULE_VAR_EXPORT auth_kerb_module = {
1062         STANDARD_MODULE_STUFF,
1063         NULL,                           /*      module initializer            */
1064         kerb_dir_create_config,         /*      per-directory config creator  */
1065         NULL,                           /*      per-directory config merger   */
1066         NULL,                           /*      per-server    config creator  */
1067         NULL,                           /*      per-server    config merger   */
1068         kerb_auth_cmds,                 /*      command table                 */
1069         NULL,                           /* [ 9] content handlers              */
1070         NULL,                           /* [ 2] URI-to-filename translation   */
1071         kerb_authenticate_user,         /* [ 5] check/validate user_id        */
1072         NULL,                           /* [ 6] check user_id is valid *here* */
1073         NULL,                           /* [ 4] check access by host address  */
1074         NULL,                           /* [ 7] MIME type checker/setter      */
1075         NULL,                           /* [ 8] fixups                        */
1076         NULL,                           /* [10] logger                        */
1077         NULL,                           /* [ 3] header parser                 */
1078         NULL,                           /*      process initialization        */
1079         NULL,                           /*      process exit/cleanup          */
1080         NULL                            /* [ 1] post read_request handling    */
1081 };
1082 #else
1083 void kerb_register_hooks(apr_pool_t *p)
1084 {
1085    ap_hook_check_user_id(kerb_authenticate_user, NULL, NULL, APR_HOOK_MIDDLE);
1086 }
1087
1088 module AP_MODULE_DECLARE_DATA auth_kerb_module =
1089 {
1090    STANDARD20_MODULE_STUFF,
1091    kerb_dir_create_config,      /* create per-dir    conf structures  */
1092    NULL,                        /* merge  per-dir    conf structures  */
1093    NULL,                        /* create per-server conf structures  */
1094    NULL,                        /* merge  per-server conf structures  */
1095    kerb_auth_cmds,              /* table of configuration directives  */
1096    kerb_register_hooks          /* register hooks                     */
1097 };
1098 #endif