src/mod_auth_kerb.c

   1 /*
   2  * Daniel Kouril <kouril@users.sourceforge.net>
   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  *   Ludek Sulak <xsulak@fi.muni.cz>
  11  */
  12
  13 /* ====================================================================
  14  * The Apache Software License, Version 1.1
  15  *
  16  * Copyright (c) 2000-2003 The Apache Software Foundation.  All rights
  17  * reserved.
  18  *
  19  * Redistribution and use in source and binary forms, with or without
  20  * modification, are permitted provided that the following conditions
  21  * are met:
  22  *
  23  * 1. Redistributions of source code must retain the above copyright
  24  *    notice, this list of conditions and the following disclaimer.
  25  *
  26  * 2. Redistributions in binary form must reproduce the above copyright
  27  *    notice, this list of conditions and the following disclaimer in
  28  *    the documentation and/or other materials provided with the
  29  *    distribution.
  30  *
  31  * 3. The end-user documentation included with the redistribution,
  32  *    if any, must include the following acknowledgment:
  33  *       "This product includes software developed by the
  34  *        Apache Software Foundation (http://www.apache.org/)."
  35  *    Alternately, this acknowledgment may appear in the software itself,
  36  *    if and wherever such third-party acknowledgments normally appear.
  37  *
  38  * 4. The names "Apache" and "Apache Software Foundation" must
  39  *    not be used to endorse or promote products derived from this
  40  *    software without prior written permission. For written
  41  *    permission, please contact apache@apache.org.
  42  *
  43  * 5. Products derived from this software may not be called "Apache",
  44  *    nor may "Apache" appear in their name, without prior written
  45  *    permission of the Apache Software Foundation.
  46  *
  47  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
  48  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  49  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  50  * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
  51  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  52  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  53  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  54  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  55  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  56  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  57  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  58  * SUCH DAMAGE.
  59  * ====================================================================
  60  *
  61  * This software consists of voluntary contributions made by many
  62  * individuals on behalf of the Apache Software Foundation.  For more
  63  * information on the Apache Software Foundation, please see
  64  * <http://www.apache.org/>.
  65  *
  66  * Portions of this software are based upon public domain software
  67  * originally written at the National Center for Supercomputing Applications,
  68  * University of Illinois, Urbana-Champaign.
  69  */
  70
  71 #ident "$Id$"
  72
  73 #include "config.h"
  74
  75 #define MODAUTHKERB_VERSION "5.0-rc2"
  76
  77 #ifndef APXS1
  78 #include "ap_compat.h"
  79 #include "apr_strings.h"
  80 #endif
  81 #include "httpd.h"
  82 #include "http_config.h"
  83 #include "http_core.h"
  84 #include "http_log.h"
  85 #include "http_protocol.h"
  86 #include "http_request.h"
  87
  88 #ifdef KRB5
  89 #include <krb5.h>
  90 #ifdef HEIMDAL
  91 #  include <gssapi.h>
  92 #else
  93 #  include <gssapi/gssapi.h>
  94 #  include <gssapi/gssapi_generic.h>
  95 #  define GSS_C_NT_USER_NAME gss_nt_user_name
  96 #  define GSS_C_NT_HOSTBASED_SERVICE gss_nt_service_name
  97 #  define krb5_get_err_text(context,code) error_message(code)
  98 #endif
  99 #endif /* KRB5 */
 100
 101 #ifdef KRB4
 102 /*Prevent warning about closesocket redefinition (Apache's ap_config.h and
 103  * MIT Kerberos' port-sockets.h both define it as close) */
 104 #ifdef closesocket
 105 #  undef closesocket
 106 #endif
 107 #include <krb.h>
 108 #include <netdb.h> /* gethostbyname() */
 109 #endif /* KRB4 */
 110
 111 #ifdef APXS1
 112 module auth_kerb_module;
 113 #else
 114 module AP_MODULE_DECLARE_DATA auth_kerb_module;
 115 #endif
 116
 117 /***************************************************************************
 118  Macros To Ease Compatibility
 119  ***************************************************************************/
 120 #ifdef APXS1
 121 #define MK_POOL pool
 122 #define MK_TABLE_GET ap_table_get
 123 #define MK_USER r->connection->user
 124 #define MK_AUTH_TYPE r->connection->ap_auth_type
 125 #else
 126 #define MK_POOL apr_pool_t
 127 #define MK_TABLE_GET apr_table_get
 128 #define MK_USER r->user
 129 #define MK_AUTH_TYPE r->ap_auth_type
 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         int krb_verify_kdc;
 140 #ifdef KRB5
 141         char *krb_5_keytab;
 142         int krb_method_gssapi;
 143         int krb_method_k5pass;
 144 #endif
 145 #ifdef KRB4
 146         char *krb_4_srvtab;
 147         int krb_method_k4pass;
 148 #endif
 149 } kerb_auth_config;
 150
 151 static const char*
 152 krb5_save_realms(cmd_parms *cmd, kerb_auth_config *sec, char *arg);
 153
 154 #ifdef APXS1
 155 #define command(name, func, var, type, usage)           \
 156   { name, func,                                         \
 157     (void*)XtOffsetOf(kerb_auth_config, var),           \
 158     OR_AUTHCFG, type, usage }
 159 #else
 160 #define command(name, func, var, type, usage)           \
 161   AP_INIT_ ## type (name, func,                         \
 162         (void*)APR_XtOffsetOf(kerb_auth_config, var),   \
 163         OR_AUTHCFG, usage)
 164 #endif
 165
 166 static const command_rec kerb_auth_cmds[] = {
 167    command("KrbAuthRealms", krb5_save_realms, krb_auth_realms,
 168      RAW_ARGS, "Realms to attempt authentication against (can be multiple)."),
 169
 170    command("KrbAuthRealm", krb5_save_realms, krb_auth_realms,
 171      RAW_ARGS, "Alias for KrbAuthRealms."),
 172
 173    command("KrbSaveCredentials", ap_set_flag_slot, krb_save_credentials,
 174      FLAG, "Save and store credentials/tickets retrieved during auth."),
 175
 176    command("KrbVerifyKDC", ap_set_flag_slot, krb_verify_kdc,
 177      FLAG, "Verify tickets against keytab to prevent KDC spoofing attacks."),
 178
 179 #ifdef KRB5
 180    command("Krb5Keytab", ap_set_file_slot, krb_5_keytab,
 181      TAKE1, "Location of Kerberos V5 keytab file."),
 182
 183    command("KrbMethodNegotiate", ap_set_flag_slot, krb_method_gssapi,
 184      FLAG, "Enable Negotiate authentication method."),
 185
 186    command("KrbMethodK5Pass", ap_set_flag_slot, krb_method_k5pass,
 187      FLAG, "Enable Kerberos V5 password authentication."),
 188 #endif
 189
 190 #ifdef KRB4
 191    command("Krb4Srvtab", ap_set_file_slot, krb_4_srvtab,
 192      TAKE1, "Location of Kerberos V4 srvtab file."),
 193
 194    command("KrbMethodK4Pass", ap_set_flag_slot, krb_method_k4pass,
 195      FLAG, "Enable Kerberos V4 password authentication."),
 196 #endif
 197
 198    { NULL }
 199 };
 200
 201 #ifdef KRB5
 202 typedef struct {
 203    gss_ctx_id_t context;
 204    gss_cred_id_t server_creds;
 205 } gss_connection_t;
 206
 207 static gss_connection_t *gss_connection = NULL;
 208 #endif
 209
 210
 211 /***************************************************************************
 212  Auth Configuration Initialization
 213  ***************************************************************************/
 214 static void *kerb_dir_create_config(MK_POOL *p, char *d)
 215 {
 216         kerb_auth_config *rec;
 217
 218         rec = (kerb_auth_config *) ap_pcalloc(p, sizeof(kerb_auth_config));
 219         ((kerb_auth_config *)rec)->krb_verify_kdc = 1;
 220 #ifdef KRB5
 221         ((kerb_auth_config *)rec)->krb_method_k5pass = 1;
 222         ((kerb_auth_config *)rec)->krb_method_gssapi = 1;
 223 #endif
 224 #ifdef KRB4
 225         ((kerb_auth_config *)rec)->krb_method_k4pass = 1;
 226 #endif
 227         return rec;
 228 }
 229
 230 static const char*
 231 krb5_save_realms(cmd_parms *cmd, kerb_auth_config *sec, char *arg)
 232 {
 233    sec->krb_auth_realms= ap_pstrdup(cmd->pool, arg);
 234    return NULL;
 235 }
 236
 237 void log_rerror(const char *file, int line, int level, int status,
 238                 const request_rec *r, const char *fmt, ...)
 239 {
 240    char errstr[1024];
 241    char errnostr[1024];
 242    va_list ap;
 243
 244    va_start(ap, fmt);
 245    vsnprintf(errstr, sizeof(errstr), fmt, ap);
 246    va_end(ap);
 247
 248    errnostr[0] = '\0';
 249    if (errno)
 250       snprintf(errnostr, sizeof(errnostr), "%s: (%s)", errstr, strerror(errno));
 251    else
 252       snprintf(errnostr, sizeof(errnostr), "%s", errstr);
 253
 254 #ifdef APXS1
 255    ap_log_rerror(file, line, level | APLOG_NOERRNO, r, "%s", errnostr);
 256 #else
 257    ap_log_rerror(file, line, level | APLOG_NOERRNO, status, r, "%s", errnostr);
 258 #endif
 259 }
 260
 261 #ifdef KRB4
 262 /***************************************************************************
 263  Username/Password Validation for Krb4
 264  ***************************************************************************/
 265 static int
 266 verify_krb4_user(request_rec *r, char *name, char *instance, char *realm,
 267                  char *password, char *linstance, char *srvtab, int krb_verify_kdc)
 268 {
 269    int ret;
 270    char *phost;
 271    unsigned long addr;
 272    struct hostent *hp;
 273    const char *hostname;
 274    KTEXT_ST ticket;
 275    AUTH_DAT authdata;
 276    char lrealm[REALM_SZ];
 277
 278    ret = krb_get_pw_in_tkt(name, instance, realm, "krbtgt", realm,
 279                            DEFAULT_TKT_LIFE, password);
 280    if (ret) {
 281       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 282                  "Cannot get krb4 ticket: krb_get_pw_in_tkt() failed: %s",
 283                  krb_get_err_text(ret));
 284       return ret;
 285    }
 286
 287    if (!krb_verify_kdc)
 288       return ret;
 289
 290    hostname = ap_get_server_name(r);
 291
 292    hp = gethostbyname(hostname);
 293    if (hp == NULL) {
 294       dest_tkt();
 295       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 296                  "Cannot verify krb4 ticket: gethostbyname() failed: %s",
 297                  hstrerror(h_errno));
 298       return h_errno;
 299    }
 300    memcpy(&addr, hp->h_addr, sizeof(addr));
 301
 302    phost = krb_get_phost((char *)hostname);
 303
 304    krb_get_lrealm(lrealm, 1);
 305
 306    ret = krb_mk_req(&ticket, linstance, phost, lrealm, 0);
 307    if (ret) {
 308       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 309                  "Cannot verify krb4 ticket: krb_mk_req() failed: %s",
 310                  krb_get_err_text(ret));
 311       dest_tkt();
 312       return ret;
 313    }
 314
 315    ret = krb_rd_req(&ticket, linstance, phost, addr, &authdata, srvtab);
 316    if (ret) {
 317       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 318                  "Cannot verify krb4 ticket: krb_rd_req() failed: %s",
 319                  krb_get_err_text(ret));
 320       dest_tkt();
 321    }
 322
 323    return ret;
 324 }
 325
 326 static int
 327 krb4_cache_cleanup(void *data)
 328 {
 329    char *tkt_file = (char *) data;
 330
 331    krb_set_tkt_string(tkt_file);
 332    dest_tkt();
 333    return OK;
 334 }
 335
 336 static int
 337 authenticate_user_krb4pwd(request_rec *r,
 338                           kerb_auth_config *conf,
 339                           const char *auth_line)
 340 {
 341    int ret;
 342    const char *sent_pw;
 343    const char *sent_name;
 344    char *sent_instance;
 345    char tkt_file[32];
 346    char *tkt_file_p = NULL;
 347    int fd;
 348    const char *realms;
 349    const char *realm;
 350    char *user;
 351    char lrealm[REALM_SZ];
 352
 353    sent_pw = ap_pbase64decode(r->pool, auth_line);
 354    sent_name = ap_getword (r->pool, &sent_pw, ':');
 355
 356    /* do not allow user to override realm setting of server */
 357    if (strchr(sent_name, '@')) {
 358       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 359                  "specifying realm in user name is prohibited");
 360       return HTTP_UNAUTHORIZED;
 361    }
 362
 363    sent_instance = strchr(sent_name, '.');
 364    if (sent_instance)
 365       *sent_instance++ = '\0';
 366
 367    snprintf(tkt_file, sizeof(tkt_file), "/tmp/apache_tkt_XXXXXX");
 368    fd = mkstemp(tkt_file);
 369    if (fd < 0) {
 370       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 371                  "Cannot create krb4 ccache: mkstemp() failed: %s",
 372                  strerror(errno));
 373       return HTTP_INTERNAL_SERVER_ERROR;
 374    }
 375
 376    tkt_file_p = ap_pstrdup(r->pool, tkt_file);
 377    ap_register_cleanup(r->pool, tkt_file_p,
 378                        krb4_cache_cleanup, ap_null_cleanup);
 379
 380    krb_set_tkt_string(tkt_file);
 381
 382    realms = conf->krb_auth_realms;
 383    do {
 384       memset(lrealm, 0, sizeof(lrealm));
 385       realm = NULL;
 386       if (realms)
 387          realm = ap_getword_white(r->pool, &realms);
 388
 389       if (realm == NULL) {
 390          ret = krb_get_lrealm(lrealm, 1);
 391          realm = lrealm;
 392       }
 393       if (realm == NULL || *realm == '\0')
 394          break;
 395
 396       ret = verify_krb4_user(r, (char *)sent_name,
 397                              (sent_instance) ? sent_instance : "",
 398                              (char *)realm, (char *)sent_pw, "khttp",
 399                              conf->krb_4_srvtab, conf->krb_verify_kdc);
 400       if (ret == 0)
 401          break;
 402    } while (realms && *realms);
 403
 404    if (ret) {
 405       log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "Verifying krb4 password failed");
 406       ret = HTTP_UNAUTHORIZED;
 407       goto end;
 408    }
 409
 410    user = ap_pstrdup(r->pool, sent_name);
 411    if (sent_instance)
 412       user = ap_pstrcat(r->pool, user, ".", sent_instance, NULL);
 413    user = ap_pstrcat(r->pool, user, "@", realm, NULL);
 414
 415    MK_USER = user;
 416    MK_AUTH_TYPE = "Basic";
 417    ap_table_setn(r->subprocess_env, "KRBTKFILE", tkt_file_p);
 418
 419    if (!conf->krb_save_credentials)
 420       krb4_cache_cleanup(tkt_file);
 421
 422 end:
 423    if (ret)
 424       krb4_cache_cleanup(tkt_file);
 425    close(fd);
 426    tf_close();
 427
 428    return ret;
 429 }
 430 #endif /* KRB4 */
 431
 432 #ifdef KRB5
 433 /***************************************************************************
 434  Username/Password Validation for Krb5
 435  ***************************************************************************/
 436 /* Inspired by krb5_verify_user from Heimdal */
 437 static krb5_error_code
 438 verify_krb5_user(request_rec *r, krb5_context context, krb5_principal principal,
 439                  krb5_ccache ccache, const char *password, const char *service,
 440                  krb5_keytab keytab, int krb_verify_kdc)
 441 {
 442    krb5_creds creds;
 443    krb5_principal server = NULL;
 444    krb5_error_code ret;
 445    krb5_verify_init_creds_opt opt;
 446
 447    memset(&creds, 0, sizeof(creds));
 448
 449    ret = krb5_get_init_creds_password(context, &creds, principal,
 450                                       (char *)password, krb5_prompter_posix,
 451                                       NULL, 0, NULL, NULL);
 452    if (ret)
 453       return ret;
 454
 455    ret = krb5_sname_to_principal(context, ap_get_server_name(r), service,
 456                                  KRB5_NT_SRV_HST, &server);
 457    if (ret)
 458       goto end;
 459
 460    krb5_verify_init_creds_opt_init(&opt);
 461    krb5_verify_init_creds_opt_set_ap_req_nofail(&opt, krb_verify_kdc);
 462
 463    ret = krb5_verify_init_creds(context, &creds, server, keytab, NULL, &opt);
 464    if (ret)
 465       goto end;
 466
 467    if (ccache) {
 468       ret = krb5_cc_initialize(context, ccache, principal);
 469       if (ret == 0)
 470          ret = krb5_cc_store_cred(context, ccache, &creds);
 471    }
 472
 473 end:
 474    krb5_free_cred_contents(context, &creds);
 475    if (server)
 476       krb5_free_principal(context, server);
 477    return ret;
 478 }
 479
 480 static int
 481 krb5_cache_cleanup(void *data)
 482 {
 483    krb5_context context;
 484    krb5_ccache  cache;
 485    krb5_error_code problem;
 486    char *cache_name = (char *) data;
 487
 488    problem = krb5_init_context(&context);
 489    if (problem) {
 490       /* ap_log_error(APLOG_MARK, APLOG_ERR, 0, NULL, "krb5_init_context() failed"); */
 491       return HTTP_INTERNAL_SERVER_ERROR;
 492    }
 493
 494    problem = krb5_cc_resolve(context, cache_name, &cache);
 495    if (problem) {
 496       /* log_error(APLOG_MARK, APLOG_ERR, 0, NULL,
 497                 "krb5_cc_resolve() failed (%s: %s)",
 498                 cache_name, krb5_get_err_text(context, problem)); */
 499       return HTTP_INTERNAL_SERVER_ERROR;
 500    }
 501
 502    krb5_cc_destroy(context, cache);
 503    krb5_free_context(context);
 504    return OK;
 505 }
 506
 507 static int
 508 create_krb5_ccache(krb5_context kcontext,
 509                    request_rec *r,
 510                    kerb_auth_config *conf,
 511                    krb5_principal princ,
 512                    krb5_ccache *ccache)
 513 {
 514    char *ccname;
 515    krb5_error_code problem;
 516    int ret;
 517    krb5_ccache tmp_ccache = NULL;
 518
 519 #ifdef HAVE_KRB5_CC_GEN_NEW
 520    problem = krb5_cc_gen_new(kcontext, &krb5_fcc_ops, &tmp_ccache);
 521 #else
 522    /* only older MIT seem to not have the krb5_cc_gen_new() call, so we use
 523     * MIT specific call here */
 524    problem = krb5_fcc_generate_new(kcontext, &tmp_ccache);
 525    /* krb5_fcc_generate_new() doesn't set KRB5_TC_OPENCLOSE, which makes
 526       krb5_cc_initialize() fail */
 527    krb5_fcc_set_flags(kcontext, tmp_ccache, KRB5_TC_OPENCLOSE);
 528 #endif
 529    if (problem) {
 530       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 531                  "Cannot create file for new krb5 ccache: %s",
 532                  krb5_get_err_text(kcontext, problem));
 533       ret = HTTP_INTERNAL_SERVER_ERROR;
 534       goto end;
 535    }
 536
 537    ccname = ap_pstrdup(r->pool, krb5_cc_get_name(kcontext, tmp_ccache));
 538
 539    problem = krb5_cc_initialize(kcontext, tmp_ccache, princ);
 540    if (problem) {
 541       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 542                  "Cannot initialize krb5 ccache %s: krb5_cc_initialize() failed: %s",
 543                  ccname, krb5_get_err_text(kcontext, problem));
 544       ret = HTTP_INTERNAL_SERVER_ERROR;
 545       goto end;
 546    }
 547
 548    ap_table_setn(r->subprocess_env, "KRB5CCNAME", ccname);
 549    ap_register_cleanup(r->pool, ccname,
 550                        krb5_cache_cleanup, ap_null_cleanup);
 551
 552    *ccache = tmp_ccache;
 553    tmp_ccache = NULL;
 554
 555    ret = OK;
 556
 557 end:
 558    if (tmp_ccache)
 559       krb5_cc_destroy(kcontext, tmp_ccache);
 560
 561    return ret;
 562 }
 563
 564 static int
 565 store_krb5_creds(krb5_context kcontext,
 566                  request_rec *r,
 567                  kerb_auth_config *conf,
 568                  krb5_ccache delegated_cred)
 569 {
 570    char errstr[1024];
 571    krb5_error_code problem;
 572    krb5_principal princ;
 573    krb5_ccache ccache;
 574    int ret;
 575
 576    problem = krb5_cc_get_principal(kcontext, delegated_cred, &princ);
 577    if (problem) {
 578       snprintf(errstr, sizeof(errstr), "krb5_cc_get_principal() failed: %s",
 579                krb5_get_err_text(kcontext, problem));
 580       return HTTP_INTERNAL_SERVER_ERROR;
 581    }
 582
 583    ret = create_krb5_ccache(kcontext, r, conf, princ, &ccache);
 584    if (ret) {
 585       krb5_free_principal(kcontext, princ);
 586       return ret;
 587    }
 588
 589 #ifdef HEIMDAL
 590    problem = krb5_cc_copy_cache(kcontext, delegated_cred, ccache);
 591 #else
 592    problem = krb5_cc_copy_creds(kcontext, delegated_cred, ccache);
 593 #endif
 594    krb5_free_principal(kcontext, princ);
 595    if (problem) {
 596       snprintf(errstr, sizeof(errstr), "Failed to store credentials: %s",
 597                krb5_get_err_text(kcontext, problem));
 598       krb5_cc_destroy(kcontext, ccache);
 599       return HTTP_INTERNAL_SERVER_ERROR;
 600    }
 601
 602    krb5_cc_close(kcontext, ccache);
 603    return OK;
 604 }
 605
 606
 607 int authenticate_user_krb5pwd(request_rec *r,
 608                               kerb_auth_config *conf,
 609                               const char *auth_line)
 610 {
 611    const char      *sent_pw = NULL;
 612    const char      *sent_name = NULL;
 613    const char      *realms = NULL;
 614    krb5_context    kcontext = NULL;
 615    krb5_error_code code;
 616    krb5_principal  client = NULL;
 617    krb5_ccache     ccache = NULL;
 618    krb5_keytab     keytab = NULL;
 619    int             ret;
 620    char *name = NULL;
 621
 622    code = krb5_init_context(&kcontext);
 623    if (code) {
 624       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 625                  "Cannot initialize Kerberos5 context (%d)", code);
 626       return HTTP_INTERNAL_SERVER_ERROR;
 627    }
 628
 629    sent_pw = ap_pbase64decode(r->pool, auth_line);
 630    sent_name = ap_getword (r->pool, &sent_pw, ':');
 631    /* do not allow user to override realm setting of server */
 632    if (strchr(sent_name, '@')) {
 633       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 634                  "specifying realm in user name is prohibited");
 635       ret = HTTP_UNAUTHORIZED;
 636       goto end;
 637    }
 638
 639 #ifdef HAVE_KRB5_CC_GEN_NEW
 640    code = krb5_cc_gen_new(kcontext, &krb5_mcc_ops, &ccache);
 641 #else
 642    /* only older MIT seem to not have the krb5_cc_gen_new() call, so we use
 643     * MIT specific call here */
 644    code = krb5_mcc_generate_new(kcontext, &ccache);
 645 #endif
 646    if (code) {
 647       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 648                  "Cannot generate new ccache: %s",
 649                  krb5_get_err_text(kcontext, code));
 650       ret = HTTP_INTERNAL_SERVER_ERROR;
 651       goto end;
 652    }
 653
 654    if (conf->krb_5_keytab)
 655       krb5_kt_resolve(kcontext, conf->krb_5_keytab, &keytab);
 656
 657    realms = conf->krb_auth_realms;
 658    do {
 659       if (realms && (code = krb5_set_default_realm(kcontext,
 660                                            ap_getword_white(r->pool, &realms))))
 661          continue;
 662
 663       if (client) {
 664          krb5_free_principal(kcontext, client);
 665          client = NULL;
 666       }
 667       code = krb5_parse_name(kcontext, sent_name, &client);
 668       if (code)
 669          continue;
 670
 671       code = verify_krb5_user(r, kcontext, client, ccache, sent_pw, "khttp",
 672                               keytab, conf->krb_verify_kdc);
 673       if (code == 0)
 674          break;
 675
 676       /* ap_getword_white() used above shifts the parameter, so it's not
 677          needed to touch the realms variable */
 678    } while (realms && *realms);
 679
 680    memset((char *)sent_pw, 0, strlen(sent_pw));
 681
 682    if (code) {
 683       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 684                  "Verifying krb5 password failed: %s",
 685                  krb5_get_err_text(kcontext, code));
 686       ret = HTTP_UNAUTHORIZED;
 687       goto end;
 688    }
 689
 690    code = krb5_unparse_name(kcontext, client, &name);
 691    if (code) {
 692       log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "krb5_unparse_name() failed: %s",
 693                  krb5_get_err_text(kcontext, code));
 694       ret = HTTP_UNAUTHORIZED;
 695       goto end;
 696    }
 697    MK_USER = ap_pstrdup (r->pool, name);
 698    MK_AUTH_TYPE = "Basic";
 699    free(name);
 700
 701    if (conf->krb_save_credentials)
 702       store_krb5_creds(kcontext, r, conf, ccache);
 703
 704    ret = OK;
 705
 706 end:
 707    if (client)
 708       krb5_free_principal(kcontext, client);
 709    if (ccache)
 710       krb5_cc_destroy(kcontext, ccache);
 711    if (keytab)
 712       krb5_kt_close(kcontext, keytab);
 713    krb5_free_context(kcontext);
 714
 715    return ret;
 716 }
 717
 718 /*********************************************************************
 719  * GSSAPI Authentication
 720  ********************************************************************/
 721
 722 static const char *
 723 get_gss_error(MK_POOL *p, OM_uint32 error_status, char *prefix)
 724 {
 725    OM_uint32 maj_stat, min_stat;
 726    OM_uint32 msg_ctx = 0;
 727    gss_buffer_desc status_string;
 728    char buf[1024];
 729    size_t len;
 730
 731    snprintf(buf, sizeof(buf), "%s", prefix);
 732    len = strlen(buf);
 733    do {
 734       maj_stat = gss_display_status (&min_stat,
 735                                      error_status,
 736                                      GSS_C_MECH_CODE,
 737                                      GSS_C_NO_OID,
 738                                      &msg_ctx,
 739                                      &status_string);
 740       if (sizeof(buf) > len + status_string.length + 1) {
 741          sprintf(buf+len, ": %s", (char*) status_string.value);
 742          len += status_string.length;
 743       }
 744       gss_release_buffer(&min_stat, &status_string);
 745    } while (!GSS_ERROR(maj_stat) && msg_ctx != 0);
 746
 747    return (ap_pstrdup(p, buf));
 748 }
 749
 750 static int
 751 cleanup_gss_connection(void *data)
 752 {
 753    OM_uint32 minor_status;
 754    gss_connection_t *gss_conn = (gss_connection_t *)data;
 755
 756    if (data == NULL)
 757       return OK;
 758    if (gss_conn->context != GSS_C_NO_CONTEXT)
 759       gss_delete_sec_context(&minor_status, &gss_conn->context,
 760                              GSS_C_NO_BUFFER);
 761    if (gss_conn->server_creds != GSS_C_NO_CREDENTIAL)
 762       gss_release_cred(&minor_status, &gss_conn->server_creds);
 763
 764    gss_connection = NULL;
 765
 766    return OK;
 767 }
 768
 769 static int
 770 store_gss_creds(request_rec *r, kerb_auth_config *conf, char *princ_name,
 771                 gss_cred_id_t delegated_cred)
 772 {
 773    OM_uint32 maj_stat, min_stat;
 774    krb5_principal princ = NULL;
 775    krb5_ccache ccache = NULL;
 776    krb5_error_code problem;
 777    krb5_context context;
 778    int ret = HTTP_INTERNAL_SERVER_ERROR;
 779
 780    problem = krb5_init_context(&context);
 781    if (problem) {
 782       log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "Cannot initialize krb5 context");
 783       return HTTP_INTERNAL_SERVER_ERROR;
 784    }
 785
 786    problem = krb5_parse_name(context, princ_name, &princ);
 787    if (problem) {
 788       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 789          "Cannot parse delegated username (%s)", krb5_get_err_text(context, problem));
 790       goto end;
 791    }
 792
 793    problem = create_krb5_ccache(context, r, conf, princ, &ccache);
 794    if (problem) {
 795       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 796          "Cannot create krb5 ccache (%s)", krb5_get_err_text(context, problem));
 797       goto end;
 798    }
 799
 800    maj_stat = gss_krb5_copy_ccache(&min_stat, delegated_cred, ccache);
 801    if (GSS_ERROR(maj_stat)) {
 802       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 803          "Cannot store delegated credential (%s)",
 804          get_gss_error(r->pool, min_stat, "gss_krb5_copy_ccache"));
 805       goto end;
 806    }
 807
 808    krb5_cc_close(context, ccache);
 809    ccache = NULL;
 810    ret = 0;
 811
 812 end:
 813    if (princ)
 814       krb5_free_principal(context, princ);
 815    if (ccache)
 816       krb5_cc_destroy(context, ccache);
 817    krb5_free_context(context);
 818    return ret;
 819 }
 820
 821 static int
 822 get_gss_creds(request_rec *r,
 823               kerb_auth_config *conf,
 824               gss_cred_id_t *server_creds)
 825 {
 826    gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
 827    OM_uint32 major_status, minor_status, minor_status2;
 828    gss_name_t server_name = GSS_C_NO_NAME;
 829    char buf[1024];
 830
 831    snprintf(buf, sizeof(buf), "%s/%s", "khttp", ap_get_server_name(r));
 832
 833    input_token.value = buf;
 834    input_token.length = strlen(buf) + 1;
 835
 836    major_status = gss_import_name(&minor_status, &input_token,
 837                                   GSS_C_NT_USER_NAME,
 838                                   &server_name);
 839    if (GSS_ERROR(major_status)) {
 840       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 841                  "%s", get_gss_error(r->pool, minor_status,
 842                  "gss_import_name() failed"));
 843       return HTTP_INTERNAL_SERVER_ERROR;
 844    }
 845
 846    major_status = gss_acquire_cred(&minor_status, server_name, GSS_C_INDEFINITE,
 847                                    GSS_C_NO_OID_SET, GSS_C_ACCEPT,
 848                                    server_creds, NULL, NULL);
 849    gss_release_name(&minor_status2, &server_name);
 850    if (GSS_ERROR(major_status)) {
 851       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 852                  "%s", get_gss_error(r->pool, minor_status,
 853                                      "gss_acquire_cred() failed"));
 854       return HTTP_INTERNAL_SERVER_ERROR;
 855    }
 856
 857    return 0;
 858 }
 859
 860 static int
 861 authenticate_user_gss(request_rec *r,
 862                       kerb_auth_config *conf,
 863                       const char *auth_line)
 864 {
 865   OM_uint32 major_status, minor_status, minor_status2;
 866   gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
 867   gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER;
 868   const char *auth_param = NULL;
 869   int ret;
 870   gss_name_t client_name = GSS_C_NO_NAME;
 871   gss_cred_id_t delegated_cred = GSS_C_NO_CREDENTIAL;
 872
 873   if (gss_connection == NULL) {
 874      gss_connection = ap_pcalloc(r->connection->pool, sizeof(*gss_connection));
 875      if (gss_connection == NULL) {
 876         log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 877                    "ap_pcalloc() failed (not enough memory)");
 878         ret = HTTP_INTERNAL_SERVER_ERROR;
 879         goto end;
 880      }
 881      memset(gss_connection, 0, sizeof(*gss_connection));
 882      ap_register_cleanup(r->connection->pool, gss_connection, cleanup_gss_connection, ap_null_cleanup);
 883   }
 884
 885   if (conf->krb_5_keytab) {
 886      char *ktname;
 887      /* we don't use the ap_* calls here, since the string passed to putenv()
 888       * will become part of the enviroment and shouldn't be free()ed by apache
 889       */
 890      ktname = malloc(strlen("KRB5_KTNAME=") + strlen(conf->krb_5_keytab) + 1);
 891      if (ktname == NULL) {
 892         log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "malloc() failed: not enough memory");
 893         ret = HTTP_INTERNAL_SERVER_ERROR;
 894         goto end;
 895      }
 896      sprintf(ktname, "KRB5_KTNAME=%s", conf->krb_5_keytab);
 897      putenv(ktname);
 898   }
 899
 900   if (gss_connection->server_creds == GSS_C_NO_CREDENTIAL) {
 901      ret = get_gss_creds(r, conf, &gss_connection->server_creds);
 902      if (ret)
 903         goto end;
 904   }
 905
 906   /* ap_getword() shifts parameter */
 907   auth_param = ap_getword_white(r->pool, &auth_line);
 908   if (auth_param == NULL) {
 909      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 910                 "No Authorization parameter in request from client");
 911      ret = HTTP_UNAUTHORIZED;
 912      goto end;
 913   }
 914
 915   input_token.length = ap_base64decode_len(auth_param) + 1;
 916   input_token.value = ap_pcalloc(r->connection->pool, input_token.length);
 917   if (input_token.value == NULL) {
 918      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 919                 "ap_pcalloc() failed (not enough memory)");
 920      ret = HTTP_INTERNAL_SERVER_ERROR;
 921      goto end;
 922   }
 923   input_token.length = ap_base64decode(input_token.value, auth_param);
 924
 925 #if 0
 926   major_status = gss_accept_sec_context(
 927 #else
 928   major_status = gss_accept_sec_context_spnego(
 929 #endif
 930                                         &minor_status,
 931                                         &gss_connection->context,
 932                                         gss_connection->server_creds,
 933                                         &input_token,
 934                                         GSS_C_NO_CHANNEL_BINDINGS,
 935                                         &client_name,
 936                                         NULL,
 937                                         &output_token,
 938                                         NULL,
 939                                         NULL,
 940                                         &delegated_cred);
 941   if (output_token.length) {
 942      char *token = NULL;
 943      size_t len;
 944
 945      len = ap_base64encode_len(output_token.length) + 1;
 946      token = ap_pcalloc(r->connection->pool, len + 1);
 947      if (token == NULL) {
 948         log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 949                    "ap_pcalloc() failed (not enough memory)");
 950         ret = HTTP_INTERNAL_SERVER_ERROR;
 951         gss_release_buffer(&minor_status2, &output_token);
 952         goto end;
 953      }
 954      ap_base64encode(token, output_token.value, output_token.length);
 955      token[len] = '\0';
 956      ap_table_set(r->err_headers_out, "WWW-Authenticate",
 957                   ap_pstrcat(r->pool, "Negotiate ", token, NULL));
 958      gss_release_buffer(&minor_status2, &output_token);
 959   }
 960
 961   if (GSS_ERROR(major_status)) {
 962      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 963                 "%s", get_gss_error(r->pool, minor_status,
 964                                     "gss_accept_sec_context() failed"));
 965      ret = HTTP_UNAUTHORIZED;
 966      goto end;
 967   }
 968
 969   if (major_status & GSS_S_CONTINUE_NEEDED) {
 970      /* Some GSSAPI mechanism (eg GSI from Globus) may require multiple
 971       * iterations to establish authentication */
 972      ret = HTTP_UNAUTHORIZED;
 973      goto end;
 974   }
 975
 976   major_status = gss_display_name(&minor_status, client_name, &output_token, NULL);
 977   gss_release_name(&minor_status, &client_name);
 978   if (GSS_ERROR(major_status)) {
 979     log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 980                "%s", get_gss_error(r->pool, minor_status,
 981                                    "gss_export_name() failed"));
 982     ret = HTTP_INTERNAL_SERVER_ERROR;
 983     goto end;
 984   }
 985
 986   MK_AUTH_TYPE = "Negotiate";
 987   MK_USER = ap_pstrdup(r->pool, output_token.value);
 988
 989   if (conf->krb_save_credentials && delegated_cred != GSS_C_NO_CREDENTIAL)
 990      store_gss_creds(r, conf, (char *)output_token.value, delegated_cred);
 991
 992   gss_release_buffer(&minor_status, &output_token);
 993
 994   ret = OK;
 995
 996 end:
 997   if (delegated_cred)
 998      gss_release_cred(&minor_status, &delegated_cred);
 999
1000   if (output_token.length)
1001      gss_release_buffer(&minor_status, &output_token);
1002
1003   if (client_name != GSS_C_NO_NAME)
1004      gss_release_name(&minor_status, &client_name);
1005
1006   cleanup_gss_connection(gss_connection);
1007
1008   return ret;
1009 }
1010 #endif /* KRB5 */
1011
1012 static int
1013 already_succeeded(request_rec *r)
1014 {
1015    if (ap_is_initial_req(r) || MK_AUTH_TYPE == NULL)
1016       return 0;
1017    if (strcmp(MK_AUTH_TYPE, "Negotiate") ||
1018        (strcmp(MK_AUTH_TYPE, "Basic") && strchr(MK_USER, '@')))
1019       return 1;
1020    return 0;
1021 }
1022
1023 static void
1024 note_kerb_auth_failure(request_rec *r, const kerb_auth_config *conf,
1025                        int use_krb4, int use_krb5)
1026 {
1027    const char *auth_name = NULL;
1028    int set_basic = 0;
1029
1030    /* get the user realm specified in .htaccess */
1031    auth_name = ap_auth_name(r);
1032
1033    /* XXX should the WWW-Authenticate header be cleared first? */
1034 #ifdef KRB5
1035    if (use_krb5 && conf->krb_method_gssapi)
1036       ap_table_add(r->err_headers_out, "WWW-Authenticate", "Negotiate");
1037    if (use_krb5 && conf->krb_method_k5pass) {
1038       ap_table_add(r->err_headers_out, "WWW-Authenticate",
1039                    ap_pstrcat(r->pool, "Basic realm=\"", auth_name, "\"", NULL));
1040       set_basic = 1;
1041    }
1042 #endif
1043
1044 #ifdef KRB4
1045    if (use_krb4 && conf->krb_method_k4pass && !set_basic)
1046       ap_table_add(r->err_headers_out, "WWW-Authenticate",
1047                    ap_pstrcat(r->pool, "Basic realm=\"", auth_name, "\"", NULL));
1048 #endif
1049 }
1050
1051 int kerb_authenticate_user(request_rec *r)
1052 {
1053    kerb_auth_config *conf =
1054       (kerb_auth_config *) ap_get_module_config(r->per_dir_config,
1055                                                 &auth_kerb_module);
1056    const char *auth_type = NULL;
1057    const char *auth_line = NULL;
1058    const char *type = NULL;
1059    int use_krb5 = 0, use_krb4 = 0;
1060    int ret;
1061    static int last_return = HTTP_UNAUTHORIZED;
1062
1063    /* get the type specified in .htaccess */
1064    type = ap_auth_type(r);
1065
1066    if (type && strcasecmp(type, "Kerberos") == 0)
1067       use_krb5 = use_krb4 = 1;
1068    else if(type && strcasecmp(type, "KerberosV5") == 0)
1069       use_krb4 = 0;
1070    else if(type && strcasecmp(type, "KerberosV4") == 0)
1071       use_krb5 = 0;
1072    else
1073       return DECLINED;
1074
1075    /* get what the user sent us in the HTTP header */
1076    auth_line = MK_TABLE_GET(r->headers_in, "Authorization");
1077    if (!auth_line) {
1078       note_kerb_auth_failure(r, conf, use_krb4, use_krb5);
1079       return HTTP_UNAUTHORIZED;
1080    }
1081    auth_type = ap_getword_white(r->pool, &auth_line);
1082
1083    if (already_succeeded(r))
1084       return last_return;
1085
1086    ret = HTTP_UNAUTHORIZED;
1087
1088 #ifdef KRB5
1089    if (use_krb5 && conf->krb_method_gssapi &&
1090        strcasecmp(auth_type, "Negotiate") == 0) {
1091       ret = authenticate_user_gss(r, conf, auth_line);
1092    } else if (use_krb5 && conf->krb_method_k5pass &&
1093               strcasecmp(auth_type, "Basic") == 0) {
1094        ret = authenticate_user_krb5pwd(r, conf, auth_line);
1095    }
1096 #endif
1097
1098 #ifdef KRB4
1099    if (ret == HTTP_UNAUTHORIZED && use_krb4 && conf->krb_method_k4pass &&
1100        strcasecmp(auth_type, "Basic") == 0)
1101       ret = authenticate_user_krb4pwd(r, conf, auth_line);
1102 #endif
1103
1104    if (ret == HTTP_UNAUTHORIZED)
1105       note_kerb_auth_failure(r, conf, use_krb4, use_krb5);
1106
1107    last_return = ret;
1108    return ret;
1109 }
1110
1111
1112 /***************************************************************************
1113  Module Setup/Configuration
1114  ***************************************************************************/
1115 #ifdef APXS1
1116 module MODULE_VAR_EXPORT auth_kerb_module = {
1117         STANDARD_MODULE_STUFF,
1118         NULL,                           /*      module initializer            */
1119         kerb_dir_create_config,         /*      per-directory config creator  */
1120         NULL,                           /*      per-directory config merger   */
1121         NULL,                           /*      per-server    config creator  */
1122         NULL,                           /*      per-server    config merger   */
1123         kerb_auth_cmds,                 /*      command table                 */
1124         NULL,                           /* [ 9] content handlers              */
1125         NULL,                           /* [ 2] URI-to-filename translation   */
1126         kerb_authenticate_user,         /* [ 5] check/validate user_id        */
1127         NULL,                           /* [ 6] check user_id is valid *here* */
1128         NULL,                           /* [ 4] check access by host address  */
1129         NULL,                           /* [ 7] MIME type checker/setter      */
1130         NULL,                           /* [ 8] fixups                        */
1131         NULL,                           /* [10] logger                        */
1132         NULL,                           /* [ 3] header parser                 */
1133         NULL,                           /*      process initialization        */
1134         NULL,                           /*      process exit/cleanup          */
1135         NULL                            /* [ 1] post read_request handling    */
1136 };
1137 #else
1138 static int
1139 kerb_init_handler(apr_pool_t *p, apr_pool_t *plog,
1140                   apr_pool_t *ptemp, server_rec *s)
1141 {
1142    ap_add_version_component(p, "mod_auth_kerb/" MODAUTHKERB_VERSION);
1143    return OK;
1144 }
1145
1146 void kerb_register_hooks(apr_pool_t *p)
1147 {
1148    ap_hook_post_config(kerb_init_handler, NULL, NULL, APR_HOOK_MIDDLE);
1149    ap_hook_check_user_id(kerb_authenticate_user, NULL, NULL, APR_HOOK_MIDDLE);
1150 }
1151
1152 module AP_MODULE_DECLARE_DATA auth_kerb_module =
1153 {
1154    STANDARD20_MODULE_STUFF,
1155    kerb_dir_create_config,      /* create per-dir    conf structures  */
1156    NULL,                        /* merge  per-dir    conf structures  */
1157    NULL,                        /* create per-server conf structures  */
1158    NULL,                        /* merge  per-server conf structures  */
1159    kerb_auth_cmds,              /* table of configuration directives  */
1160    kerb_register_hooks          /* register hooks                     */
1161 };
1162 #endif