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 #ifdef HEIMDAL
  86 #  include <gssapi.h>
  87 #else
  88 #  include <gssapi/gssapi.h>
  89 #  include <gssapi/gssapi_generic.h>
  90 #  define GSS_C_NT_USER_NAME gss_nt_user_name
  91 #  define GSS_C_NT_HOSTBASED_SERVICE gss_nt_service_name
  92 #  define krb5_get_err_text(context,code) error_message(code)
  93 #endif
  94 #endif /* KRB5 */
  95
  96 #ifdef KRB4
  97 /*Prevent warning about closesocket redefinition (Apache's ap_config.h and
  98  * MIT Kerberos' port-sockets.h both define it as close) */
  99 #ifdef closesocket
 100 #  undef closesocket
 101 #endif
 102 #include <krb.h>
 103 #endif /* KRB4 */
 104
 105 #ifdef APXS1
 106 module auth_kerb_module;
 107 #else
 108 module AP_MODULE_DECLARE_DATA auth_kerb_module;
 109 #endif
 110
 111 /***************************************************************************
 112  Macros To Ease Compatibility
 113  ***************************************************************************/
 114 #ifdef APXS1
 115 #define MK_POOL pool
 116 #define MK_TABLE_GET ap_table_get
 117 #define MK_TABLE_SET ap_table_set
 118 #define MK_TABLE_TYPE table
 119 #define MK_PSTRDUP ap_pstrdup
 120 #define MK_USER r->connection->user
 121 #define MK_AUTH_TYPE r->connection->ap_auth_type
 122 #define MK_ARRAY_HEADER array_header
 123 #else
 124 #define MK_POOL apr_pool_t
 125 #define MK_TABLE_GET apr_table_get
 126 #define MK_TABLE_SET apr_table_set
 127 #define MK_TABLE_TYPE apr_table_t
 128 #define MK_PSTRDUP apr_pstrdup
 129 #define MK_USER r->user
 130 #define MK_AUTH_TYPE r->ap_auth_type
 131 #define MK_ARRAY_HEADER apr_array_header_t
 132 #endif /* APXS1 */
 133
 134
 135 /***************************************************************************
 136  Auth Configuration Structure
 137  ***************************************************************************/
 138 typedef struct {
 139         char *krb_auth_realms;
 140         int krb_save_credentials;
 141 #ifdef KRB5
 142         char *krb_5_keytab;
 143         int krb_method_gssapi;
 144         int krb_method_k5pass;
 145 #endif
 146 #ifdef KRB4
 147         char *krb_4_srvtab;
 148         int krb_method_k4pass;
 149 #endif
 150 } kerb_auth_config;
 151
 152 static const char*
 153 krb5_save_realms(cmd_parms *cmd, kerb_auth_config *sec, char *arg);
 154
 155 #ifdef APXS1
 156 #define command(name, func, var, type, usage)           \
 157   { name, func,                                         \
 158     (void*)XtOffsetOf(kerb_auth_config, var),           \
 159     OR_AUTHCFG, type, usage }
 160 #else
 161 #define command(name, func, var, type, usage)           \
 162   AP_INIT_ ## type (name, func,                         \
 163         (void*)APR_XtOffsetOf(kerb_auth_config, var),   \
 164         OR_AUTHCFG, usage)
 165 #endif
 166
 167 static const command_rec kerb_auth_cmds[] = {
 168    command("KrbAuthRealms", krb5_save_realms, krb_auth_realms,
 169      RAW_ARGS, "Realms to attempt authentication against (can be multiple)."),
 170
 171    command("KrbAuthRealm", krb5_save_realms, krb_auth_realms,
 172      RAW_ARGS, "Alias for KrbAuthRealms."),
 173
 174    command("KrbSaveCredentials", ap_set_flag_slot, krb_save_credentials,
 175      FLAG, "Save and store credentials/tickets retrieved during auth."),
 176
 177 #ifdef KRB5
 178    command("Krb5Keytab", ap_set_file_slot, krb_5_keytab,
 179      TAKE1, "Location of Kerberos V5 keytab file."),
 180
 181    command("KrbMethodNegotiate", ap_set_flag_slot, krb_method_gssapi,
 182      FLAG, "Enable Negotiate authentication method."),
 183
 184    command("KrbMethodK5Pass", ap_set_flag_slot, krb_method_k5pass,
 185      FLAG, "Enable Kerberos V5 password authentication."),
 186 #endif
 187
 188 #ifdef KRB4
 189    command("Krb4Srvtab", ap_set_file_slot, krb_4_srvtab,
 190      TAKE1, "Location of Kerberos V4 srvtab file."),
 191
 192    command("KrbMethodK4Pass", ap_set_flag_slot, krb_method_k4pass,
 193      FLAG, "Enable Kerberos V4 password authentication."),
 194 #endif
 195
 196    { NULL }
 197 };
 198
 199 #ifdef KRB5
 200 typedef struct {
 201    gss_ctx_id_t context;
 202    gss_cred_id_t server_creds;
 203 } gss_connection_t;
 204
 205 static gss_connection_t *gss_connection = NULL;
 206 #endif
 207
 208
 209 /***************************************************************************
 210  Auth Configuration Initialization
 211  ***************************************************************************/
 212 static void *kerb_dir_create_config(MK_POOL *p, char *d)
 213 {
 214         kerb_auth_config *rec;
 215
 216         rec = (kerb_auth_config *) ap_pcalloc(p, sizeof(kerb_auth_config));
 217 #ifdef KRB5
 218         ((kerb_auth_config *)rec)->krb_method_k5pass = 1;
 219         ((kerb_auth_config *)rec)->krb_method_gssapi = 1;
 220 #endif
 221 #ifdef KRB4
 222         ((kerb_auth_config *)rec)->krb_method_k4pass = 1;
 223 #endif
 224         return rec;
 225 }
 226
 227 static const char*
 228 krb5_save_realms(cmd_parms *cmd, kerb_auth_config *sec, char *arg)
 229 {
 230    sec->krb_auth_realms= ap_pstrdup(cmd->pool, arg);
 231    return NULL;
 232 }
 233
 234 void log_rerror(const char *file, int line, int level, int status,
 235                 const request_rec *r, const char *fmt, ...)
 236 {
 237    char errstr[1024];
 238    va_list ap;
 239
 240    va_start(ap, fmt);
 241    vsnprintf(errstr, sizeof(errstr), fmt, ap);
 242    va_end(ap);
 243
 244 #ifdef APXS1
 245    ap_log_rerror(file, line, level, r, "%s", errstr);
 246 #else
 247    ap_log_rerror(file, line, level, status, r, "%s", errstr);
 248 #endif
 249 }
 250
 251 #ifdef KRB4
 252 /***************************************************************************
 253  Username/Password Validation for Krb4
 254  ***************************************************************************/
 255 static int
 256 verify_krb4_user(request_rec *r, char *name, char *instance, char *realm,
 257                  char *password, char *linstance, char *srvtab)
 258 {
 259    int ret;
 260    char *phost;
 261    unsigned long addr;
 262    struct hostent *hp;
 263    const char *hostname;
 264    KTEXT_ST ticket;
 265    AUTH_DAT authdata;
 266    char lrealm[REALM_SZ];
 267
 268    ret = krb_get_pw_in_tkt(name, instance, realm, "krbtgt", realm,
 269                            DEFAULT_TKT_LIFE, password);
 270    if (ret)
 271       /* log(krb_err_txt[ret]) */
 272       return ret;
 273
 274    hostname = ap_get_server_name(r);
 275
 276    hp = gethostbyname(hostname);
 277    if (hp == NULL) {
 278       dest_tkt();
 279       return h_errno;
 280    }
 281    memcpy(&addr, hp->h_addr, sizeof(addr));
 282
 283    phost = krb_get_phost((char *)hostname);
 284
 285    krb_get_lrealm(lrealm, 1);
 286
 287    ret = krb_mk_req(&ticket, linstance, phost, lrealm, 0);
 288    if (ret) {
 289       dest_tkt();
 290       return ret;
 291    }
 292
 293    ret = krb_rd_req(&ticket, linstance, phost, addr, &authdata, srvtab);
 294    if (ret)
 295       dest_tkt();
 296
 297    return ret;
 298 }
 299
 300 static int
 301 krb4_cache_cleanup(void *data)
 302 {
 303    char *tkt_file = (char *) data;
 304
 305    krb_set_tkt_string(tkt_file);
 306    dest_tkt();
 307    return OK;
 308 }
 309
 310 static int
 311 authenticate_user_krb4pwd(request_rec *r,
 312                           kerb_auth_config *conf,
 313                           const char *auth_line)
 314 {
 315    int ret;
 316    const char *sent_pw;
 317    const char *sent_name;
 318    char *sent_instance;
 319    char tkt_file[32];
 320    char *tkt_file_p = NULL;
 321    int fd;
 322    const char *realms;
 323    const char *realm;
 324    char *user;
 325    char lrealm[REALM_SZ];
 326
 327    sent_pw = ap_pbase64decode(r->pool, auth_line);
 328    sent_name = ap_getword (r->pool, &sent_pw, ':');
 329
 330    /* do not allow user to override realm setting of server */
 331    if (strchr(sent_name, '@')) {
 332       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 333                  "specifying realm in user name is prohibited");
 334       return HTTP_UNAUTHORIZED;
 335    }
 336
 337    sent_instance = strchr(sent_name, '.');
 338    if (sent_instance)
 339       *sent_instance++ = '\0';
 340
 341    snprintf(tkt_file, sizeof(tkt_file), "/tmp/apache_tkt_XXXXXX");
 342    fd = mkstemp(tkt_file);
 343    if (fd < 0) {
 344       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 345                  "Cannot create krb4 ccache: mkstemp() failed: %s",
 346                  strerror(errno));
 347       return HTTP_INTERNAL_SERVER_ERROR;
 348    }
 349
 350    tkt_file_p = ap_pstrdup(r->pool, tkt_file);
 351    ap_register_cleanup(r->pool, tkt_file_p,
 352                        krb4_cache_cleanup, ap_null_cleanup);
 353
 354    krb_set_tkt_string(tkt_file);
 355
 356    realms = conf->krb_auth_realms;
 357    do {
 358       memset(lrealm, 0, sizeof(lrealm));
 359       realm = NULL;
 360       if (realms)
 361          realm = ap_getword_white(r->pool, &realms);
 362
 363       if (realm == NULL) {
 364          ret = krb_get_lrealm(lrealm, 1);
 365          realm = lrealm;
 366       }
 367       if (realm == NULL || *realm == '\0')
 368          break;
 369
 370       ret = verify_krb4_user(r, (char *)sent_name,
 371                              (sent_instance) ? sent_instance : "",
 372                              (char *)realm, (char *)sent_pw, "khttp",
 373                              conf->krb_4_srvtab);
 374       if (ret == 0)
 375          break;
 376    } while (realms && *realms);
 377
 378    if (ret) {
 379       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 380                  "Verifying krb4 password failed (%d)", ret);
 381       ret = HTTP_UNAUTHORIZED;
 382       goto end;
 383    }
 384
 385    user = ap_pstrdup(r->pool, sent_name);
 386    if (sent_instance)
 387       user = ap_pstrcat(r->pool, user, ".", sent_instance, NULL);
 388    user = ap_pstrcat(r->pool, user, "@", realm, NULL);
 389
 390    MK_USER = user;
 391    MK_AUTH_TYPE = "Basic";
 392    ap_table_setn(r->subprocess_env, "KRBTKFILE", tkt_file_p);
 393
 394    if (!conf->krb_save_credentials)
 395       krb4_cache_cleanup(tkt_file);
 396
 397 end:
 398    if (ret)
 399       krb4_cache_cleanup(tkt_file);
 400    close(fd);
 401    tf_close();
 402
 403    return ret;
 404 }
 405 #endif /* KRB4 */
 406
 407 #ifdef KRB5
 408 /***************************************************************************
 409  Username/Password Validation for Krb5
 410  ***************************************************************************/
 411 /* Inspired by krb5_verify_user from Heimdal */
 412 static krb5_error_code
 413 verify_krb5_user(request_rec *r, krb5_context context, krb5_principal principal,
 414                  krb5_ccache ccache, const char *password, const char *service,
 415                  krb5_keytab keytab)
 416 {
 417    krb5_creds creds;
 418    krb5_principal server = NULL;
 419    krb5_error_code ret;
 420    krb5_verify_init_creds_opt opt;
 421
 422    memset(&creds, 0, sizeof(creds));
 423
 424    ret = krb5_get_init_creds_password(context, &creds, principal,
 425                                       (char *)password, krb5_prompter_posix,
 426                                       NULL, 0, NULL, NULL);
 427    if (ret)
 428       return ret;
 429
 430    ret = krb5_sname_to_principal(context, ap_get_server_name(r), service,
 431                                  KRB5_NT_SRV_HST, &server);
 432    if (ret)
 433       goto end;
 434
 435    krb5_verify_init_creds_opt_init(&opt);
 436    krb5_verify_init_creds_opt_set_ap_req_nofail(&opt, 1);
 437
 438    ret = krb5_verify_init_creds(context, &creds, server, keytab, NULL, &opt);
 439    if (ret)
 440       goto end;
 441
 442    if (ccache) {
 443       ret = krb5_cc_initialize(context, ccache, principal);
 444       if (ret == 0)
 445          ret = krb5_cc_store_cred(context, ccache, &creds);
 446    }
 447
 448 end:
 449    krb5_free_cred_contents(context, &creds);
 450    if (server)
 451       krb5_free_principal(context, server);
 452    return ret;
 453 }
 454
 455 static int
 456 krb5_cache_cleanup(void *data)
 457 {
 458    krb5_context context;
 459    krb5_ccache  cache;
 460    krb5_error_code problem;
 461    char *cache_name = (char *) data;
 462
 463    problem = krb5_init_context(&context);
 464    if (problem) {
 465       /* ap_log_error(APLOG_MARK, APLOG_ERR, 0, NULL, "krb5_init_context() failed"); */
 466       return HTTP_INTERNAL_SERVER_ERROR;
 467    }
 468
 469    problem = krb5_cc_resolve(context, cache_name, &cache);
 470    if (problem) {
 471       /* log_error(APLOG_MARK, APLOG_ERR, 0, NULL,
 472                 "krb5_cc_resolve() failed (%s: %s)",
 473                 cache_name, krb5_get_err_text(context, problem)); */
 474       return HTTP_INTERNAL_SERVER_ERROR;
 475    }
 476
 477    krb5_cc_destroy(context, cache);
 478    krb5_free_context(context);
 479    return OK;
 480 }
 481
 482 static int
 483 create_krb5_ccache(krb5_context kcontext,
 484                    request_rec *r,
 485                    kerb_auth_config *conf,
 486                    krb5_principal princ,
 487                    krb5_ccache *ccache)
 488 {
 489    char *ccname;
 490    krb5_error_code problem;
 491    int ret;
 492    krb5_ccache tmp_ccache = NULL;
 493
 494 #ifdef HEIMDAL
 495    problem = krb5_cc_gen_new(kcontext, &krb5_fcc_ops, &tmp_ccache);
 496 #else
 497    problem = krb5_fcc_generate_new(kcontext, &tmp_ccache);
 498    /* krb5_fcc_generate_new() doesn't set KRB5_TC_OPENCLOSE, which makes
 499       krb5_cc_initialize() fail */
 500    krb5_fcc_set_flags(kcontext, tmp_ccache, KRB5_TC_OPENCLOSE);
 501 #endif
 502    if (problem) {
 503       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 504                  "Cannot create file for new krb5 ccache: %s",
 505                  krb5_get_err_text(kcontext, problem));
 506       ret = HTTP_INTERNAL_SERVER_ERROR;
 507       goto end;
 508    }
 509
 510    ccname = ap_pstrdup(r->pool, krb5_cc_get_name(kcontext, tmp_ccache));
 511
 512    problem = krb5_cc_initialize(kcontext, tmp_ccache, princ);
 513    if (problem) {
 514       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 515                  "Cannot initialize krb5 ccache %s: krb5_cc_initialize() failed: %s",
 516                  ccname, krb5_get_err_text(kcontext, problem));
 517       ret = HTTP_INTERNAL_SERVER_ERROR;
 518       goto end;
 519    }
 520
 521    ap_table_setn(r->subprocess_env, "KRB5CCNAME", ccname);
 522    ap_register_cleanup(r->pool, ccname,
 523                        krb5_cache_cleanup, ap_null_cleanup);
 524
 525    *ccache = tmp_ccache;
 526    tmp_ccache = NULL;
 527
 528    ret = OK;
 529
 530 end:
 531    if (tmp_ccache)
 532       krb5_cc_destroy(kcontext, tmp_ccache);
 533
 534    return ret;
 535 }
 536
 537 static int
 538 store_krb5_creds(krb5_context kcontext,
 539                  request_rec *r,
 540                  kerb_auth_config *conf,
 541                  krb5_ccache delegated_cred)
 542 {
 543    char errstr[1024];
 544    krb5_error_code problem;
 545    krb5_principal princ;
 546    krb5_ccache ccache;
 547    int ret;
 548
 549    problem = krb5_cc_get_principal(kcontext, delegated_cred, &princ);
 550    if (problem) {
 551       snprintf(errstr, sizeof(errstr), "krb5_cc_get_principal() failed: %s",
 552                krb5_get_err_text(kcontext, problem));
 553       return HTTP_INTERNAL_SERVER_ERROR;
 554    }
 555
 556    ret = create_krb5_ccache(kcontext, r, conf, princ, &ccache);
 557    if (ret) {
 558       krb5_free_principal(kcontext, princ);
 559       return ret;
 560    }
 561
 562 #ifdef HEIMDAL
 563    problem = krb5_cc_copy_cache(kcontext, delegated_cred, ccache);
 564 #else
 565    problem = krb5_cc_copy_creds(kcontext, delegated_cred, ccache);
 566 #endif
 567    krb5_free_principal(kcontext, princ);
 568    if (problem) {
 569       snprintf(errstr, sizeof(errstr), "Failed to store credentials: %s",
 570                krb5_get_err_text(kcontext, problem));
 571       krb5_cc_destroy(kcontext, ccache);
 572       return HTTP_INTERNAL_SERVER_ERROR;
 573    }
 574
 575    krb5_cc_close(kcontext, ccache);
 576    return OK;
 577 }
 578
 579
 580 int authenticate_user_krb5pwd(request_rec *r,
 581                               kerb_auth_config *conf,
 582                               const char *auth_line)
 583 {
 584    const char      *sent_pw = NULL;
 585    const char      *sent_name = NULL;
 586    const char      *realms = NULL;
 587    krb5_context    kcontext = NULL;
 588    krb5_error_code code;
 589    krb5_principal  client = NULL;
 590    krb5_ccache     ccache = NULL;
 591    krb5_keytab     keytab = NULL;
 592    int             ret;
 593    char *name = NULL;
 594
 595    code = krb5_init_context(&kcontext);
 596    if (code) {
 597       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 598                  "Cannot initialize Kerberos5 context (%d)", code);
 599       return HTTP_INTERNAL_SERVER_ERROR;
 600    }
 601
 602    sent_pw = ap_pbase64decode(r->pool, auth_line);
 603    sent_name = ap_getword (r->pool, &sent_pw, ':');
 604    /* do not allow user to override realm setting of server */
 605    if (strchr(sent_name, '@')) {
 606       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 607                  "specifying realm in user name is prohibited");
 608       ret = HTTP_UNAUTHORIZED;
 609       goto end;
 610    }
 611
 612 #ifdef HEIMDAL
 613    code = krb5_cc_gen_new(kcontext, &krb5_mcc_ops, &ccache);
 614 #else
 615    code = krb5_mcc_generate_new(kcontext, &ccache);
 616 #endif
 617    if (code) {
 618       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 619                  "Cannot generate new ccache: %s",
 620                  krb5_get_err_text(kcontext, code));
 621       ret = HTTP_INTERNAL_SERVER_ERROR;
 622       goto end;
 623    }
 624
 625    if (conf->krb_5_keytab)
 626       krb5_kt_resolve(kcontext, conf->krb_5_keytab, &keytab);
 627       /* setenv("KRB5_KTNAME", conf->krb_5_keytab, 1); */
 628
 629    realms = conf->krb_auth_realms;
 630    do {
 631       if (realms && (code = krb5_set_default_realm(kcontext,
 632                                            ap_getword_white(r->pool, &realms))))
 633          continue;
 634
 635       if (client) {
 636          krb5_free_principal(kcontext, client);
 637          client = NULL;
 638       }
 639       code = krb5_parse_name(kcontext, sent_name, &client);
 640       if (code)
 641          continue;
 642
 643       code = verify_krb5_user(r, kcontext, client, ccache, sent_pw, "khttp",
 644                               keytab);
 645       if (code == 0)
 646          break;
 647
 648       /* ap_getword_white() used above shifts the parameter, so it's not
 649          needed to touch the realms variable */
 650    } while (realms && *realms);
 651
 652    memset((char *)sent_pw, 0, strlen(sent_pw));
 653
 654    if (code) {
 655       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 656                  "Verifying krb5 password failed: %s",
 657                  krb5_get_err_text(kcontext, code));
 658       ret = HTTP_UNAUTHORIZED;
 659       goto end;
 660    }
 661
 662    code = krb5_unparse_name(kcontext, client, &name);
 663    if (code) {
 664       log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "krb5_unparse_name() failed: %s",
 665                  krb5_get_err_text(kcontext, code));
 666       ret = HTTP_UNAUTHORIZED;
 667       goto end;
 668    }
 669    MK_USER = ap_pstrdup (r->pool, name);
 670    MK_AUTH_TYPE = "Basic";
 671    free(name);
 672
 673    if (conf->krb_save_credentials)
 674       store_krb5_creds(kcontext, r, conf, ccache);
 675
 676    ret = OK;
 677
 678 end:
 679    if (client)
 680       krb5_free_principal(kcontext, client);
 681    if (ccache)
 682       krb5_cc_destroy(kcontext, ccache);
 683    if (keytab)
 684       krb5_kt_close(kcontext, keytab);
 685    krb5_free_context(kcontext);
 686
 687    return ret;
 688 }
 689
 690 /*********************************************************************
 691  * GSSAPI Authentication
 692  ********************************************************************/
 693
 694 static const char *
 695 get_gss_error(MK_POOL *p, OM_uint32 error_status, char *prefix)
 696 {
 697    OM_uint32 maj_stat, min_stat;
 698    OM_uint32 msg_ctx = 0;
 699    gss_buffer_desc status_string;
 700    char buf[1024];
 701    size_t len;
 702
 703    snprintf(buf, sizeof(buf), "%s", prefix);
 704    len = strlen(buf);
 705    do {
 706       maj_stat = gss_display_status (&min_stat,
 707                                      error_status,
 708                                      GSS_C_MECH_CODE,
 709                                      GSS_C_NO_OID,
 710                                      &msg_ctx,
 711                                      &status_string);
 712       if (sizeof(buf) > len + status_string.length + 1) {
 713          sprintf(buf+len, ": %s", (char*) status_string.value);
 714          len += status_string.length;
 715       }
 716       gss_release_buffer(&min_stat, &status_string);
 717    } while (!GSS_ERROR(maj_stat) && msg_ctx != 0);
 718
 719    return (ap_pstrdup(p, buf));
 720 }
 721
 722 static int
 723 cleanup_gss_connection(void *data)
 724 {
 725    OM_uint32 minor_status;
 726    gss_connection_t *gss_conn = (gss_connection_t *)data;
 727
 728    if (data == NULL)
 729       return OK;
 730    if (gss_conn->context != GSS_C_NO_CONTEXT)
 731       gss_delete_sec_context(&minor_status, &gss_conn->context,
 732                              GSS_C_NO_BUFFER);
 733    if (gss_conn->server_creds != GSS_C_NO_CREDENTIAL)
 734       gss_release_cred(&minor_status, &gss_conn->server_creds);
 735
 736    gss_connection = NULL;
 737
 738    return OK;
 739 }
 740
 741 static int
 742 store_gss_creds(request_rec *r, kerb_auth_config *conf, char *princ_name,
 743                 gss_cred_id_t delegated_cred)
 744 {
 745    OM_uint32 maj_stat, min_stat;
 746    krb5_principal princ = NULL;
 747    krb5_ccache ccache = NULL;
 748    krb5_error_code problem;
 749    krb5_context context;
 750    int ret = HTTP_INTERNAL_SERVER_ERROR;
 751
 752    problem = krb5_init_context(&context);
 753    if (problem) {
 754       log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "Cannot initialize krb5 context");
 755       return HTTP_INTERNAL_SERVER_ERROR;
 756    }
 757
 758    problem = krb5_parse_name(context, princ_name, &princ);
 759    if (problem) {
 760       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 761          "Cannot parse delegated username (%s)", krb5_get_err_text(context, problem));
 762       goto end;
 763    }
 764
 765    problem = create_krb5_ccache(context, r, conf, princ, &ccache);
 766    if (problem) {
 767       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 768          "Cannot create krb5 ccache (%s)", krb5_get_err_text(context, problem));
 769       goto end;
 770    }
 771
 772    maj_stat = gss_krb5_copy_ccache(&min_stat, delegated_cred, ccache);
 773    if (GSS_ERROR(maj_stat)) {
 774       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 775          "Cannot store delegated credential (%s)",
 776          get_gss_error(r->pool, min_stat, "gss_krb5_copy_ccache"));
 777       goto end;
 778    }
 779
 780    krb5_cc_close(context, ccache);
 781    ccache = NULL;
 782    ret = 0;
 783
 784 end:
 785    if (princ)
 786       krb5_free_principal(context, princ);
 787    if (ccache)
 788       krb5_cc_destroy(context, ccache);
 789    krb5_free_context(context);
 790    return ret;
 791 }
 792
 793 static int
 794 get_gss_creds(request_rec *r,
 795               kerb_auth_config *conf,
 796               gss_cred_id_t *server_creds)
 797 {
 798    gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
 799    OM_uint32 major_status, minor_status, minor_status2;
 800    gss_name_t server_name = GSS_C_NO_NAME;
 801    char buf[1024];
 802
 803    snprintf(buf, sizeof(buf), "%s/%s", "khttp", ap_get_server_name(r));
 804
 805    input_token.value = buf;
 806    input_token.length = strlen(buf) + 1;
 807
 808    major_status = gss_import_name(&minor_status, &input_token,
 809                                   GSS_C_NT_USER_NAME,
 810                                   &server_name);
 811    if (GSS_ERROR(major_status)) {
 812       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 813                  "%s", get_gss_error(r->pool, minor_status,
 814                  "gss_import_name() failed"));
 815       return HTTP_INTERNAL_SERVER_ERROR;
 816    }
 817
 818    major_status = gss_acquire_cred(&minor_status, server_name, GSS_C_INDEFINITE,
 819                                    GSS_C_NO_OID_SET, GSS_C_ACCEPT,
 820                                    server_creds, NULL, NULL);
 821    gss_release_name(&minor_status2, &server_name);
 822    if (GSS_ERROR(major_status)) {
 823       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 824                  "%s", get_gss_error(r->pool, minor_status,
 825                                      "gss_acquire_cred() failed"));
 826       return HTTP_INTERNAL_SERVER_ERROR;
 827    }
 828
 829    return 0;
 830 }
 831
 832 static int
 833 authenticate_user_gss(request_rec *r,
 834                       kerb_auth_config *conf,
 835                       const char *auth_line)
 836 {
 837   OM_uint32 major_status, minor_status, minor_status2;
 838   gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
 839   gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER;
 840   const char *auth_param = NULL;
 841   int ret;
 842   gss_name_t client_name = GSS_C_NO_NAME;
 843   gss_cred_id_t delegated_cred = GSS_C_NO_CREDENTIAL;
 844   static int initial_return = HTTP_UNAUTHORIZED;
 845
 846   /* needed to work around replay caches */
 847   if (!ap_is_initial_req(r))
 848      return initial_return;
 849   initial_return = HTTP_UNAUTHORIZED;
 850
 851   if (gss_connection == NULL) {
 852      gss_connection = ap_pcalloc(r->connection->pool, sizeof(*gss_connection));
 853      if (gss_connection == NULL) {
 854         log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 855                    "ap_pcalloc() failed (not enough memory)");
 856         ret = HTTP_INTERNAL_SERVER_ERROR;
 857         goto end;
 858      }
 859      memset(gss_connection, 0, sizeof(*gss_connection));
 860      ap_register_cleanup(r->connection->pool, gss_connection, cleanup_gss_connection, ap_null_cleanup);
 861   }
 862
 863   if (conf->krb_5_keytab)
 864      setenv("KRB5_KTNAME", conf->krb_5_keytab, 1);
 865
 866   if (gss_connection->server_creds == GSS_C_NO_CREDENTIAL) {
 867      ret = get_gss_creds(r, conf, &gss_connection->server_creds);
 868      if (ret)
 869         goto end;
 870   }
 871
 872   /* ap_getword() shifts parameter */
 873   auth_param = ap_getword_white(r->pool, &auth_line);
 874   if (auth_param == NULL) {
 875      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 876                 "No Authorization parameter in request from client");
 877      ret = HTTP_UNAUTHORIZED;
 878      goto end;
 879   }
 880
 881   input_token.length = ap_base64decode_len(auth_param) + 1;
 882   input_token.value = ap_pcalloc(r->connection->pool, input_token.length);
 883   if (input_token.value == NULL) {
 884      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 885                 "ap_pcalloc() failed (not enough memory)");
 886      ret = HTTP_INTERNAL_SERVER_ERROR;
 887      goto end;
 888   }
 889   input_token.length = ap_base64decode(input_token.value, auth_param);
 890
 891   major_status = gss_accept_sec_context(&minor_status,
 892                                         &gss_connection->context,
 893                                         gss_connection->server_creds,
 894                                         &input_token,
 895                                         GSS_C_NO_CHANNEL_BINDINGS,
 896                                         &client_name,
 897                                         NULL,
 898                                         &output_token,
 899                                         NULL,
 900                                         NULL,
 901                                         &delegated_cred);
 902   if (output_token.length) {
 903      char *token = NULL;
 904      size_t len;
 905
 906      len = ap_base64encode_len(output_token.length) + 1;
 907      token = ap_pcalloc(r->connection->pool, len + 1);
 908      if (token == NULL) {
 909         log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 910                    "ap_pcalloc() failed (not enough memory)");
 911         ret = HTTP_INTERNAL_SERVER_ERROR;
 912         gss_release_buffer(&minor_status2, &output_token);
 913         goto end;
 914      }
 915      ap_base64encode(token, output_token.value, output_token.length);
 916      token[len] = '\0';
 917      ap_table_set(r->err_headers_out, "WWW-Authenticate",
 918                   ap_pstrcat(r->pool, "GSS-Negotiate ", token, NULL));
 919      gss_release_buffer(&minor_status2, &output_token);
 920   }
 921
 922   if (GSS_ERROR(major_status)) {
 923      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 924                 "%s", get_gss_error(r->pool, minor_status,
 925                                     "gss_accept_sec_context() failed"));
 926      ret = HTTP_UNAUTHORIZED;
 927      goto end;
 928   }
 929
 930   if (major_status & GSS_S_CONTINUE_NEEDED) {
 931      /* Some GSSAPI mechanism (eg GSI from Globus) may require multiple
 932       * iterations to establish authentication */
 933      ret = HTTP_UNAUTHORIZED;
 934      goto end;
 935   }
 936
 937   major_status = gss_display_name(&minor_status, client_name, &output_token, NULL);
 938   gss_release_name(&minor_status, &client_name);
 939   if (GSS_ERROR(major_status)) {
 940     log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 941                "%s", get_gss_error(r->pool, minor_status,
 942                                    "gss_export_name() failed"));
 943     ret = HTTP_INTERNAL_SERVER_ERROR;
 944     goto end;
 945   }
 946
 947   MK_AUTH_TYPE = "Negotiate";
 948   MK_USER = ap_pstrdup(r->pool, output_token.value);
 949
 950   if (conf->krb_save_credentials && delegated_cred != GSS_C_NO_CREDENTIAL)
 951      store_gss_creds(r, conf, (char *)output_token.value, delegated_cred);
 952
 953   gss_release_buffer(&minor_status, &output_token);
 954
 955   ret = OK;
 956
 957 end:
 958   if (delegated_cred)
 959      gss_release_cred(&minor_status, &delegated_cred);
 960
 961   if (output_token.length)
 962      gss_release_buffer(&minor_status, &output_token);
 963
 964   if (client_name != GSS_C_NO_NAME)
 965      gss_release_name(&minor_status, &client_name);
 966
 967   cleanup_gss_connection(gss_connection);
 968
 969   initial_return = ret;
 970   return ret;
 971 }
 972 #endif /* KRB5 */
 973
 974
 975 static void
 976 note_kerb_auth_failure(request_rec *r, const kerb_auth_config *conf,
 977                        int use_krb4, int use_krb5)
 978 {
 979    const char *auth_name = NULL;
 980    int set_basic = 0;
 981
 982    /* get the user realm specified in .htaccess */
 983    auth_name = ap_auth_name(r);
 984
 985    /* XXX should the WWW-Authenticate header be cleared first? */
 986 #ifdef KRB5
 987    if (use_krb5 && conf->krb_method_gssapi)
 988       ap_table_add(r->err_headers_out, "WWW-Authenticate", "GSS-Negotiate ");
 989    if (use_krb5 && conf->krb_method_k5pass) {
 990       ap_table_add(r->err_headers_out, "WWW-Authenticate",
 991                    ap_pstrcat(r->pool, "Basic realm=\"", auth_name, "\"", NULL));
 992       set_basic = 1;
 993    }
 994 #endif
 995
 996 #ifdef KRB4
 997    if (use_krb4 && conf->krb_method_k4pass && !set_basic)
 998       ap_table_add(r->err_headers_out, "WWW-Authenticate",
 999                    ap_pstrcat(r->pool, "Basic realm=\"", auth_name, "\"", NULL));
1000 #endif
1001 }
1002
1003 int kerb_authenticate_user(request_rec *r)
1004 {
1005    kerb_auth_config *conf =
1006       (kerb_auth_config *) ap_get_module_config(r->per_dir_config,
1007                                                 &auth_kerb_module);
1008    const char *auth_type = NULL;
1009    const char *auth_line = NULL;
1010    const char *type = NULL;
1011    int use_krb5 = 0, use_krb4 = 0;
1012    int ret;
1013
1014    /* get the type specified in .htaccess */
1015    type = ap_auth_type(r);
1016
1017    if (type && strcasecmp(type, "Kerberos") == 0)
1018       use_krb5 = use_krb4 = 1;
1019    else if(type && strcasecmp(type, "KerberosV5") == 0)
1020       use_krb4 = 0;
1021    else if(type && strcasecmp(type, "KerberosV4") == 0)
1022       use_krb5 = 0;
1023    else
1024       return DECLINED;
1025
1026    /* get what the user sent us in the HTTP header */
1027    auth_line = MK_TABLE_GET(r->headers_in, "Authorization");
1028    if (!auth_line) {
1029       note_kerb_auth_failure(r, conf, use_krb4, use_krb5);
1030       return HTTP_UNAUTHORIZED;
1031    }
1032    auth_type = ap_getword_white(r->pool, &auth_line);
1033
1034    ret = HTTP_UNAUTHORIZED;
1035
1036 #ifdef KRB5
1037    if (use_krb5 && conf->krb_method_gssapi &&
1038        strcasecmp(auth_type, "GSS-Negotiate") == 0) {
1039       ret = authenticate_user_gss(r, conf, auth_line);
1040    } else if (use_krb5 && conf->krb_method_k5pass &&
1041               strcasecmp(auth_type, "Basic") == 0) {
1042        ret = authenticate_user_krb5pwd(r, conf, auth_line);
1043    }
1044 #endif
1045
1046 #ifdef KRB4
1047    if (ret == HTTP_UNAUTHORIZED && use_krb4 && conf->krb_method_k4pass &&
1048        strcasecmp(auth_type, "Basic") == 0)
1049       ret = authenticate_user_krb4pwd(r, conf, auth_line);
1050 #endif
1051
1052    if (ret == HTTP_UNAUTHORIZED)
1053       note_kerb_auth_failure(r, conf, use_krb4, use_krb5);
1054
1055    return ret;
1056 }
1057
1058
1059 /***************************************************************************
1060  Module Setup/Configuration
1061  ***************************************************************************/
1062 #ifdef APXS1
1063 module MODULE_VAR_EXPORT auth_kerb_module = {
1064         STANDARD_MODULE_STUFF,
1065         NULL,                           /*      module initializer            */
1066         kerb_dir_create_config,         /*      per-directory config creator  */
1067         NULL,                           /*      per-directory config merger   */
1068         NULL,                           /*      per-server    config creator  */
1069         NULL,                           /*      per-server    config merger   */
1070         kerb_auth_cmds,                 /*      command table                 */
1071         NULL,                           /* [ 9] content handlers              */
1072         NULL,                           /* [ 2] URI-to-filename translation   */
1073         kerb_authenticate_user,         /* [ 5] check/validate user_id        */
1074         NULL,                           /* [ 6] check user_id is valid *here* */
1075         NULL,                           /* [ 4] check access by host address  */
1076         NULL,                           /* [ 7] MIME type checker/setter      */
1077         NULL,                           /* [ 8] fixups                        */
1078         NULL,                           /* [10] logger                        */
1079         NULL,                           /* [ 3] header parser                 */
1080         NULL,                           /*      process initialization        */
1081         NULL,                           /*      process exit/cleanup          */
1082         NULL                            /* [ 1] post read_request handling    */
1083 };
1084 #else
1085 void kerb_register_hooks(apr_pool_t *p)
1086 {
1087    ap_hook_check_user_id(kerb_authenticate_user, NULL, NULL, APR_HOOK_MIDDLE);
1088 }
1089
1090 module AP_MODULE_DECLARE_DATA auth_kerb_module =
1091 {
1092    STANDARD20_MODULE_STUFF,
1093    kerb_dir_create_config,      /* create per-dir    conf structures  */
1094    NULL,                        /* merge  per-dir    conf structures  */
1095    NULL,                        /* create per-server conf structures  */
1096    NULL,                        /* merge  per-server conf structures  */
1097    kerb_auth_cmds,              /* table of configuration directives  */
1098    kerb_register_hooks          /* register hooks                     */
1099 };
1100 #endif