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  *   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 #ifndef APXS1
  74 #include "ap_compat.h"
  75 #include "apr_strings.h"
  76 #endif
  77 #include "httpd.h"
  78 #include "http_config.h"
  79 #include "http_core.h"
  80 #include "http_log.h"
  81 #include "http_protocol.h"
  82 #include "http_request.h"
  83
  84 #ifdef KRB5
  85 #include <krb5.h>
  86 #include <gssapi.h>
  87 #ifndef HEIMDAL
  88 #  include <gssapi_generic.h>
  89 #  define GSS_C_NT_USER_NAME gss_nt_user_name
  90 #  define GSS_C_NT_HOSTBASED_SERVICE gss_nt_service_name
  91 #  define krb5_get_err_text(context,code) error_message(code)
  92 #endif
  93 #endif /* KRB5 */
  94
  95 #ifdef KRB4
  96 /*Prevent warning about closesocket redefinition (Apache's ap_config.h and
  97  * MIT Kerberos' port-sockets.h both define it as close) */
  98 #ifdef closesocket
  99 #  undef closesocket
 100 #endif
 101 #include <krb.h>
 102 #endif /* KRB4 */
 103
 104 #ifdef APXS1
 105 module auth_kerb_module;
 106 #else
 107 module AP_MODULE_DECLARE_DATA auth_kerb_module;
 108 #endif
 109
 110 /***************************************************************************
 111  Macros To Ease Compatibility
 112  ***************************************************************************/
 113 #ifdef APXS1
 114 #define MK_POOL pool
 115 #define MK_TABLE_GET ap_table_get
 116 #define MK_TABLE_SET ap_table_set
 117 #define MK_TABLE_TYPE table
 118 #define MK_PSTRDUP ap_pstrdup
 119 #define MK_USER r->connection->user
 120 #define MK_AUTH_TYPE r->connection->ap_auth_type
 121 #define MK_ARRAY_HEADER array_header
 122 #else
 123 #define MK_POOL apr_pool_t
 124 #define MK_TABLE_GET apr_table_get
 125 #define MK_TABLE_SET apr_table_set
 126 #define MK_TABLE_TYPE apr_table_t
 127 #define MK_PSTRDUP apr_pstrdup
 128 #define MK_USER r->user
 129 #define MK_AUTH_TYPE r->ap_auth_type
 130 #define MK_ARRAY_HEADER apr_array_header_t
 131 #endif /* APXS1 */
 132
 133
 134 /***************************************************************************
 135  Auth Configuration Structure
 136  ***************************************************************************/
 137 typedef struct {
 138         char *krb_auth_realms;
 139         int krb_save_credentials;
 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 #ifdef KRB5
 177    command("Krb5Keytab", ap_set_file_slot, krb_5_keytab,
 178      TAKE1, "Location of Kerberos V5 keytab file."),
 179
 180    command("KrbMethodNegotiate", ap_set_flag_slot, krb_method_gssapi,
 181      FLAG, "Enable Negotiate authentication method."),
 182
 183    command("KrbMethodK5Pass", ap_set_flag_slot, krb_method_k5pass,
 184      FLAG, "Enable Kerberos V5 password authentication."),
 185 #endif
 186
 187 #ifdef KRB4
 188    command("Krb4Srvtab", ap_set_file_slot, krb_4_srvtab,
 189      TAKE1, "Location of Kerberos V4 srvtab file."),
 190
 191    command("KrbMethodK4Pass", ap_set_flag_slot, krb_method_k4pass,
 192      FLAG, "Enable Kerberos V4 password authentication."),
 193 #endif
 194
 195    { NULL }
 196 };
 197
 198 #ifdef KRB5
 199 typedef struct {
 200    gss_ctx_id_t context;
 201    gss_cred_id_t server_creds;
 202 } gss_connection_t;
 203
 204 static gss_connection_t *gss_connection = NULL;
 205 #endif
 206
 207
 208 /***************************************************************************
 209  Auth Configuration Initialization
 210  ***************************************************************************/
 211 static void *kerb_dir_create_config(MK_POOL *p, char *d)
 212 {
 213         kerb_auth_config *rec;
 214
 215         rec = (kerb_auth_config *) ap_pcalloc(p, sizeof(kerb_auth_config));
 216 #ifdef KRB5
 217         ((kerb_auth_config *)rec)->krb_method_k5pass = 1;
 218         ((kerb_auth_config *)rec)->krb_method_gssapi = 1;
 219 #endif
 220 #ifdef KRB4
 221         ((kerb_auth_config *)rec)->krb_method_k4pass = 1;
 222 #endif
 223         return rec;
 224 }
 225
 226 static const char*
 227 krb5_save_realms(cmd_parms *cmd, kerb_auth_config *sec, char *arg)
 228 {
 229    sec->krb_auth_realms= ap_pstrdup(cmd->pool, arg);
 230    return NULL;
 231 }
 232
 233 void log_rerror(const char *file, int line, int level, int status,
 234                 const request_rec *r, const char *fmt, ...)
 235 {
 236    char errstr[1024];
 237    va_list ap;
 238
 239    va_start(ap, fmt);
 240    vsnprintf(errstr, sizeof(errstr), fmt, ap);
 241    va_end(ap);
 242
 243 #ifdef APXS1
 244    ap_log_rerror(file, line, level, r, "%s", errstr);
 245 #else
 246    ap_log_rerror(file, line, level, status, r, "%s", errstr);
 247 #endif
 248 }
 249
 250 #ifdef KRB4
 251 /***************************************************************************
 252  Username/Password Validation for Krb4
 253  ***************************************************************************/
 254 static int
 255 verify_krb4_user(request_rec *r, char *name, char *instance, char *realm,
 256                  char *password, char *linstance, char *srvtab)
 257 {
 258    int ret;
 259    char *phost;
 260    unsigned long addr;
 261    struct hostent *hp;
 262    const char *hostname;
 263    KTEXT_ST ticket;
 264    AUTH_DAT authdata;
 265    char lrealm[REALM_SZ];
 266
 267    ret = krb_get_pw_in_tkt(name, instance, realm, "krbtgt", realm,
 268                            DEFAULT_TKT_LIFE, password);
 269    if (ret)
 270       /* log(krb_err_txt[ret]) */
 271       return ret;
 272
 273    hostname = ap_get_server_name(r);
 274
 275    hp = gethostbyname(hostname);
 276    if (hp == NULL) {
 277       dest_tkt();
 278       return h_errno;
 279    }
 280    memcpy(&addr, hp->h_addr, sizeof(addr));
 281
 282    phost = krb_get_phost((char *)hostname);
 283
 284    krb_get_lrealm(lrealm, 1);
 285
 286    ret = krb_mk_req(&ticket, linstance, phost, lrealm, 0);
 287    if (ret) {
 288       dest_tkt();
 289       return ret;
 290    }
 291
 292    ret = krb_rd_req(&ticket, linstance, phost, addr, &authdata, srvtab);
 293    if (ret)
 294       dest_tkt();
 295
 296    return ret;
 297 }
 298
 299 static int
 300 krb4_cache_cleanup(void *data)
 301 {
 302    char *tkt_file = (char *) data;
 303
 304    krb_set_tkt_string(tkt_file);
 305    dest_tkt();
 306    return OK;
 307 }
 308
 309 static int
 310 authenticate_user_krb4pwd(request_rec *r,
 311                           kerb_auth_config *conf,
 312                           const char *auth_line)
 313 {
 314    int ret;
 315    const char *sent_pw;
 316    const char *sent_name;
 317    char *sent_instance;
 318    char tkt_file[32];
 319    char *tkt_file_p = NULL;
 320    int fd;
 321    const char *realms;
 322    const char *realm;
 323    char *user;
 324    char lrealm[REALM_SZ];
 325
 326    sent_pw = ap_pbase64decode(r->pool, auth_line);
 327    sent_name = ap_getword (r->pool, &sent_pw, ':');
 328
 329    /* do not allow user to override realm setting of server */
 330    if (strchr(sent_name, '@')) {
 331       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 332                  "specifying realm in user name is prohibited");
 333       return HTTP_UNAUTHORIZED;
 334    }
 335
 336    sent_instance = strchr(sent_name, '.');
 337    if (sent_instance)
 338       *sent_instance++ = '\0';
 339
 340    snprintf(tkt_file, sizeof(tkt_file), "/tmp/apache_tkt_XXXXXX");
 341    fd = mkstemp(tkt_file);
 342    if (fd < 0) {
 343       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 344                  "Cannot create krb4 ccache: mkstemp() failed: %s",
 345                  strerror(errno));
 346       return HTTP_INTERNAL_SERVER_ERROR;
 347    }
 348
 349    tkt_file_p = ap_pstrdup(r->pool, tkt_file);
 350    ap_register_cleanup(r->pool, tkt_file_p,
 351                        krb4_cache_cleanup, ap_null_cleanup);
 352
 353    krb_set_tkt_string(tkt_file);
 354
 355    realms = conf->krb_auth_realms;
 356    do {
 357       memset(lrealm, 0, sizeof(lrealm));
 358       realm = NULL;
 359       if (realms)
 360          realm = ap_getword_white(r->pool, &realms);
 361
 362       if (realm == NULL) {
 363          ret = krb_get_lrealm(lrealm, 1);
 364          realm = lrealm;
 365       }
 366       if (realm == NULL || *realm == '\0')
 367          break;
 368
 369       ret = verify_krb4_user(r, (char *)sent_name,
 370                              (sent_instance) ? sent_instance : "",
 371                              (char *)realm, (char *)sent_pw, "khttp",
 372                              conf->krb_4_srvtab);
 373       if (ret == 0)
 374          break;
 375    } while (realms && *realms);
 376
 377    if (ret) {
 378       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 379                  "Verifying krb4 password failed (%d)", ret);
 380       ret = HTTP_UNAUTHORIZED;
 381       goto end;
 382    }
 383
 384    user = ap_pstrdup(r->pool, sent_name);
 385    if (sent_instance)
 386       user = ap_pstrcat(r->pool, user, ".", sent_instance, NULL);
 387    user = ap_pstrcat(r->pool, user, "@", realm, NULL);
 388
 389    MK_USER = user;
 390    MK_AUTH_TYPE = "Basic";
 391    ap_table_setn(r->subprocess_env, "KRBTKFILE", tkt_file_p);
 392
 393    if (!conf->krb_save_credentials)
 394       krb4_cache_cleanup(tkt_file);
 395
 396 end:
 397    if (ret)
 398       krb4_cache_cleanup(tkt_file);
 399    close(fd);
 400    tf_close();
 401
 402    return ret;
 403 }
 404 #endif /* KRB4 */
 405
 406 #ifdef KRB5
 407 /***************************************************************************
 408  Username/Password Validation for Krb5
 409  ***************************************************************************/
 410 /* Inspired by krb5_verify_user from Heimdal */
 411 static krb5_error_code
 412 verify_krb5_user(request_rec *r, krb5_context context, krb5_principal principal,
 413                  krb5_ccache ccache, const char *password, const char *service,
 414                  krb5_keytab keytab)
 415 {
 416    krb5_creds creds;
 417    krb5_principal server = NULL;
 418    krb5_error_code ret;
 419    krb5_verify_init_creds_opt opt;
 420
 421    memset(&creds, 0, sizeof(creds));
 422
 423    ret = krb5_get_init_creds_password(context, &creds, principal,
 424                                       (char *)password, krb5_prompter_posix,
 425                                       NULL, 0, NULL, NULL);
 426    if (ret)
 427       return ret;
 428
 429    ret = krb5_sname_to_principal(context, ap_get_server_name(r), service,
 430                                  KRB5_NT_SRV_HST, &server);
 431    if (ret)
 432       goto end;
 433
 434    krb5_verify_init_creds_opt_init(&opt);
 435    krb5_verify_init_creds_opt_set_ap_req_nofail(&opt, 1);
 436
 437    ret = krb5_verify_init_creds(context, &creds, server, keytab, NULL, &opt);
 438    if (ret)
 439       goto end;
 440
 441    if (ccache) {
 442       ret = krb5_cc_initialize(context, ccache, principal);
 443       if (ret == 0)
 444          ret = krb5_cc_store_cred(context, ccache, &creds);
 445    }
 446
 447 end:
 448    krb5_free_cred_contents(context, &creds);
 449    if (server)
 450       krb5_free_principal(context, server);
 451    return ret;
 452 }
 453
 454 static int
 455 krb5_cache_cleanup(void *data)
 456 {
 457    krb5_context context;
 458    krb5_ccache  cache;
 459    krb5_error_code problem;
 460    char *cache_name = (char *) data;
 461
 462    problem = krb5_init_context(&context);
 463    if (problem) {
 464       /* ap_log_error(APLOG_MARK, APLOG_ERR, 0, NULL, "krb5_init_context() failed"); */
 465       return HTTP_INTERNAL_SERVER_ERROR;
 466    }
 467
 468    problem = krb5_cc_resolve(context, cache_name, &cache);
 469    if (problem) {
 470       /* log_error(APLOG_MARK, APLOG_ERR, 0, NULL,
 471                 "krb5_cc_resolve() failed (%s: %s)",
 472                 cache_name, krb5_get_err_text(context, problem)); */
 473       return HTTP_INTERNAL_SERVER_ERROR;
 474    }
 475
 476    krb5_cc_destroy(context, cache);
 477    krb5_free_context(context);
 478    return OK;
 479 }
 480
 481 static int
 482 create_krb5_ccache(krb5_context kcontext,
 483                    request_rec *r,
 484                    kerb_auth_config *conf,
 485                    krb5_principal princ,
 486                    krb5_ccache *ccache)
 487 {
 488    char *ccname;
 489    krb5_error_code problem;
 490    int ret;
 491    krb5_ccache tmp_ccache = NULL;
 492
 493 #ifdef HEIMDAL
 494    problem = krb5_cc_gen_new(kcontext, &krb5_fcc_ops, &tmp_ccache);
 495 #else
 496    problem = krb5_fcc_generate_new(kcontext, &tmp_ccache);
 497    /* krb5_fcc_generate_new() doesn't set KRB5_TC_OPENCLOSE, which makes
 498       krb5_cc_initialize() fail */
 499    krb5_fcc_set_flags(kcontext, tmp_ccache, KRB5_TC_OPENCLOSE);
 500 #endif
 501    if (problem) {
 502       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 503                  "Cannot create file for new krb5 ccache: %s",
 504                  krb5_get_err_text(kcontext, problem));
 505       ret = HTTP_INTERNAL_SERVER_ERROR;
 506       goto end;
 507    }
 508
 509    ccname = ap_pstrdup(r->pool, krb5_cc_get_name(kcontext, tmp_ccache));
 510
 511    problem = krb5_cc_initialize(kcontext, tmp_ccache, princ);
 512    if (problem) {
 513       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 514                  "Cannot initialize krb5 ccache %s: krb5_cc_initialize() failed: %s",
 515                  ccname, krb5_get_err_text(kcontext, problem));
 516       ret = HTTP_INTERNAL_SERVER_ERROR;
 517       goto end;
 518    }
 519
 520    ap_table_setn(r->subprocess_env, "KRB5CCNAME", ccname);
 521    ap_register_cleanup(r->pool, ccname,
 522                        krb5_cache_cleanup, ap_null_cleanup);
 523
 524    *ccache = tmp_ccache;
 525    tmp_ccache = NULL;
 526
 527    ret = OK;
 528
 529 end:
 530    if (tmp_ccache)
 531       krb5_cc_destroy(kcontext, tmp_ccache);
 532
 533    return ret;
 534 }
 535
 536 static int
 537 store_krb5_creds(krb5_context kcontext,
 538                  request_rec *r,
 539                  kerb_auth_config *conf,
 540                  krb5_ccache delegated_cred)
 541 {
 542    char errstr[1024];
 543    krb5_error_code problem;
 544    krb5_principal princ;
 545    krb5_ccache ccache;
 546    int ret;
 547
 548    problem = krb5_cc_get_principal(kcontext, delegated_cred, &princ);
 549    if (problem) {
 550       snprintf(errstr, sizeof(errstr), "krb5_cc_get_principal() failed: %s",
 551                krb5_get_err_text(kcontext, problem));
 552       return HTTP_INTERNAL_SERVER_ERROR;
 553    }
 554
 555    ret = create_krb5_ccache(kcontext, r, conf, princ, &ccache);
 556    if (ret) {
 557       krb5_free_principal(kcontext, princ);
 558       return ret;
 559    }
 560
 561 #ifdef HEIMDAL
 562    problem = krb5_cc_copy_cache(kcontext, delegated_cred, ccache);
 563 #else
 564    problem = krb5_cc_copy_creds(kcontext, delegated_cred, ccache);
 565 #endif
 566    krb5_free_principal(kcontext, princ);
 567    if (problem) {
 568       snprintf(errstr, sizeof(errstr), "Failed to store credentials: %s",
 569                krb5_get_err_text(kcontext, problem));
 570       krb5_cc_destroy(kcontext, ccache);
 571       return HTTP_INTERNAL_SERVER_ERROR;
 572    }
 573
 574    krb5_cc_close(kcontext, ccache);
 575    return OK;
 576 }
 577
 578
 579 int authenticate_user_krb5pwd(request_rec *r,
 580                               kerb_auth_config *conf,
 581                               const char *auth_line)
 582 {
 583    const char      *sent_pw = NULL;
 584    const char      *sent_name = NULL;
 585    const char      *realms = NULL;
 586    krb5_context    kcontext = NULL;
 587    krb5_error_code code;
 588    krb5_principal  client = NULL;
 589    krb5_ccache     ccache = NULL;
 590    krb5_keytab     keytab = NULL;
 591    int             ret;
 592    char *name = NULL;
 593
 594    code = krb5_init_context(&kcontext);
 595    if (code) {
 596       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 597                  "Cannot initialize Kerberos5 context (%d)", code);
 598       return HTTP_INTERNAL_SERVER_ERROR;
 599    }
 600
 601    sent_pw = ap_pbase64decode(r->pool, auth_line);
 602    sent_name = ap_getword (r->pool, &sent_pw, ':');
 603    /* do not allow user to override realm setting of server */
 604    if (strchr(sent_name, '@')) {
 605       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 606                  "specifying realm in user name is prohibited");
 607       ret = HTTP_UNAUTHORIZED;
 608       goto end;
 609    }
 610
 611 #ifdef HEIMDAL
 612    code = krb5_cc_gen_new(kcontext, &krb5_mcc_ops, &ccache);
 613 #else
 614    code = krb5_mcc_generate_new(kcontext, &ccache);
 615 #endif
 616    if (code) {
 617       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 618                  "Cannot generate new ccache: %s",
 619                  krb5_get_err_text(kcontext, code));
 620       ret = HTTP_INTERNAL_SERVER_ERROR;
 621       goto end;
 622    }
 623
 624    if (conf->krb_5_keytab)
 625       krb5_kt_resolve(kcontext, conf->krb_5_keytab, &keytab);
 626       /* setenv("KRB5_KTNAME", conf->krb_5_keytab, 1); */
 627
 628    realms = conf->krb_auth_realms;
 629    do {
 630       if (realms && (code = krb5_set_default_realm(kcontext,
 631                                            ap_getword_white(r->pool, &realms))))
 632          continue;
 633
 634       if (client) {
 635          krb5_free_principal(kcontext, client);
 636          client = NULL;
 637       }
 638       code = krb5_parse_name(kcontext, sent_name, &client);
 639       if (code)
 640          continue;
 641
 642       code = verify_krb5_user(r, kcontext, client, ccache, sent_pw, "khttp",
 643                               keytab);
 644       if (code == 0)
 645          break;
 646
 647       /* ap_getword_white() used above shifts the parameter, so it's not
 648          needed to touch the realms variable */
 649    } while (realms && *realms);
 650
 651    memset((char *)sent_pw, 0, strlen(sent_pw));
 652
 653    if (code) {
 654       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 655                  "Verifying krb5 password failed: %s",
 656                  krb5_get_err_text(kcontext, code));
 657       ret = HTTP_UNAUTHORIZED;
 658       goto end;
 659    }
 660
 661    code = krb5_unparse_name(kcontext, client, &name);
 662    if (code) {
 663       log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "krb5_unparse_name() failed: %s",
 664                  krb5_get_err_text(kcontext, code));
 665       ret = HTTP_UNAUTHORIZED;
 666       goto end;
 667    }
 668    MK_USER = ap_pstrdup (r->pool, name);
 669    MK_AUTH_TYPE = "Basic";
 670    free(name);
 671
 672    if (conf->krb_save_credentials)
 673       store_krb5_creds(kcontext, r, conf, ccache);
 674
 675    ret = OK;
 676
 677 end:
 678    if (client)
 679       krb5_free_principal(kcontext, client);
 680    if (ccache)
 681       krb5_cc_destroy(kcontext, ccache);
 682    if (keytab)
 683       krb5_kt_close(kcontext, keytab);
 684    krb5_free_context(kcontext);
 685
 686    return ret;
 687 }
 688
 689 /*********************************************************************
 690  * GSSAPI Authentication
 691  ********************************************************************/
 692
 693 static const char *
 694 get_gss_error(MK_POOL *p, OM_uint32 error_status, char *prefix)
 695 {
 696    OM_uint32 maj_stat, min_stat;
 697    OM_uint32 msg_ctx = 0;
 698    gss_buffer_desc status_string;
 699    char buf[1024];
 700    size_t len;
 701
 702    snprintf(buf, sizeof(buf), "%s", prefix);
 703    len = strlen(buf);
 704    do {
 705       maj_stat = gss_display_status (&min_stat,
 706                                      error_status,
 707                                      GSS_C_MECH_CODE,
 708                                      GSS_C_NO_OID,
 709                                      &msg_ctx,
 710                                      &status_string);
 711       if (sizeof(buf) > len + status_string.length + 1) {
 712          sprintf(buf+len, ": %s", (char*) status_string.value);
 713          len += status_string.length;
 714       }
 715       gss_release_buffer(&min_stat, &status_string);
 716    } while (!GSS_ERROR(maj_stat) && msg_ctx != 0);
 717
 718    return (ap_pstrdup(p, buf));
 719 }
 720
 721 static int
 722 cleanup_gss_connection(void *data)
 723 {
 724    OM_uint32 minor_status;
 725    gss_connection_t *gss_conn = (gss_connection_t *)data;
 726
 727    if (data == NULL)
 728       return OK;
 729    if (gss_conn->context != GSS_C_NO_CONTEXT)
 730       gss_delete_sec_context(&minor_status, &gss_conn->context,
 731                              GSS_C_NO_BUFFER);
 732    if (gss_conn->server_creds != GSS_C_NO_CREDENTIAL)
 733       gss_release_cred(&minor_status, &gss_conn->server_creds);
 734
 735    gss_connection = NULL;
 736
 737    return OK;
 738 }
 739
 740 static int
 741 store_gss_creds(request_rec *r, kerb_auth_config *conf, char *princ_name,
 742                 gss_cred_id_t delegated_cred)
 743 {
 744    OM_uint32 maj_stat, min_stat;
 745    krb5_principal princ = NULL;
 746    krb5_ccache ccache = NULL;
 747    krb5_error_code problem;
 748    krb5_context context;
 749    int ret = HTTP_INTERNAL_SERVER_ERROR;
 750
 751    problem = krb5_init_context(&context);
 752    if (problem) {
 753       log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "Cannot initialize krb5 context");
 754       return HTTP_INTERNAL_SERVER_ERROR;
 755    }
 756
 757    problem = krb5_parse_name(context, princ_name, &princ);
 758    if (problem) {
 759       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 760          "Cannot parse delegated username (%s)", krb5_get_err_text(context, problem));
 761       goto end;
 762    }
 763
 764    problem = create_krb5_ccache(context, r, conf, princ, &ccache);
 765    if (problem) {
 766       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 767          "Cannot create krb5 ccache (%s)", krb5_get_err_text(context, problem));
 768       goto end;
 769    }
 770
 771    maj_stat = gss_krb5_copy_ccache(&min_stat, delegated_cred, ccache);
 772    if (GSS_ERROR(maj_stat)) {
 773       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 774          "Cannot store delegated credential (%s)",
 775          get_gss_error(r->pool, min_stat, "gss_krb5_copy_ccache"));
 776       goto end;
 777    }
 778
 779    krb5_cc_close(context, ccache);
 780    ccache = NULL;
 781    ret = 0;
 782
 783 end:
 784    if (princ)
 785       krb5_free_principal(context, princ);
 786    if (ccache)
 787       krb5_cc_destroy(context, ccache);
 788    krb5_free_context(context);
 789    return ret;
 790 }
 791
 792 static int
 793 get_gss_creds(request_rec *r,
 794               kerb_auth_config *conf,
 795               gss_cred_id_t *server_creds)
 796 {
 797    gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
 798    OM_uint32 major_status, minor_status, minor_status2;
 799    gss_name_t server_name = GSS_C_NO_NAME;
 800    char buf[1024];
 801
 802    snprintf(buf, sizeof(buf), "%s/%s", "khttp", ap_get_server_name(r));
 803
 804    input_token.value = buf;
 805    input_token.length = strlen(buf) + 1;
 806
 807    major_status = gss_import_name(&minor_status, &input_token,
 808                                   GSS_C_NT_USER_NAME,
 809                                   &server_name);
 810    if (GSS_ERROR(major_status)) {
 811       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 812                  "%s", get_gss_error(r->pool, minor_status,
 813                  "gss_import_name() failed"));
 814       return HTTP_INTERNAL_SERVER_ERROR;
 815    }
 816
 817    major_status = gss_acquire_cred(&minor_status, server_name, GSS_C_INDEFINITE,
 818                                    GSS_C_NO_OID_SET, GSS_C_ACCEPT,
 819                                    server_creds, NULL, NULL);
 820    gss_release_name(&minor_status2, &server_name);
 821    if (GSS_ERROR(major_status)) {
 822       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 823                  "%s", get_gss_error(r->pool, minor_status,
 824                                      "gss_acquire_cred() failed"));
 825       return HTTP_INTERNAL_SERVER_ERROR;
 826    }
 827
 828    return 0;
 829 }
 830
 831 static int
 832 authenticate_user_gss(request_rec *r,
 833                       kerb_auth_config *conf,
 834                       const char *auth_line)
 835 {
 836   OM_uint32 major_status, minor_status, minor_status2;
 837   gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
 838   gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER;
 839   const char *auth_param = NULL;
 840   int ret;
 841   gss_name_t client_name = GSS_C_NO_NAME;
 842   gss_cred_id_t delegated_cred = GSS_C_NO_CREDENTIAL;
 843   static int initial_return = HTTP_UNAUTHORIZED;
 844
 845   /* needed to work around replay caches */
 846   if (!ap_is_initial_req(r))
 847      return initial_return;
 848   initial_return = HTTP_UNAUTHORIZED;
 849
 850   if (gss_connection == NULL) {
 851      gss_connection = ap_pcalloc(r->connection->pool, sizeof(*gss_connection));
 852      if (gss_connection == NULL) {
 853         log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 854                    "ap_pcalloc() failed (not enough memory)");
 855         ret = HTTP_INTERNAL_SERVER_ERROR;
 856         goto end;
 857      }
 858      memset(gss_connection, 0, sizeof(*gss_connection));
 859      ap_register_cleanup(r->connection->pool, gss_connection, cleanup_gss_connection, ap_null_cleanup);
 860   }
 861
 862   if (conf->krb_5_keytab)
 863      setenv("KRB5_KTNAME", conf->krb_5_keytab, 1);
 864
 865   if (gss_connection->server_creds == GSS_C_NO_CREDENTIAL) {
 866      ret = get_gss_creds(r, conf, &gss_connection->server_creds);
 867      if (ret)
 868         goto end;
 869   }
 870
 871   /* ap_getword() shifts parameter */
 872   auth_param = ap_getword_white(r->pool, &auth_line);
 873   if (auth_param == NULL) {
 874      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 875                 "No Authorization parameter in request from client");
 876      ret = HTTP_UNAUTHORIZED;
 877      goto end;
 878   }
 879
 880   input_token.length = ap_base64decode_len(auth_param) + 1;
 881   input_token.value = ap_pcalloc(r->connection->pool, input_token.length);
 882   if (input_token.value == NULL) {
 883      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 884                 "ap_pcalloc() failed (not enough memory)");
 885      ret = HTTP_INTERNAL_SERVER_ERROR;
 886      goto end;
 887   }
 888   input_token.length = ap_base64decode(input_token.value, auth_param);
 889
 890   major_status = gss_accept_sec_context(&minor_status,
 891                                         &gss_connection->context,
 892                                         gss_connection->server_creds,
 893                                         &input_token,
 894                                         GSS_C_NO_CHANNEL_BINDINGS,
 895                                         &client_name,
 896                                         NULL,
 897                                         &output_token,
 898                                         NULL,
 899                                         NULL,
 900                                         &delegated_cred);
 901   if (output_token.length) {
 902      char *token = NULL;
 903      size_t len;
 904
 905      len = ap_base64encode_len(output_token.length) + 1;
 906      token = ap_pcalloc(r->connection->pool, len + 1);
 907      if (token == NULL) {
 908         log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 909                    "ap_pcalloc() failed (not enough memory)");
 910         ret = HTTP_INTERNAL_SERVER_ERROR;
 911         gss_release_buffer(&minor_status2, &output_token);
 912         goto end;
 913      }
 914      ap_base64encode(token, output_token.value, output_token.length);
 915      token[len] = '\0';
 916      ap_table_set(r->err_headers_out, "WWW-Authenticate",
 917                   ap_pstrcat(r->pool, "GSS-Negotiate ", token, NULL));
 918      gss_release_buffer(&minor_status2, &output_token);
 919   }
 920
 921   if (GSS_ERROR(major_status)) {
 922      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 923                 "%s", get_gss_error(r->pool, minor_status,
 924                                     "gss_accept_sec_context() failed"));
 925      ret = HTTP_UNAUTHORIZED;
 926      goto end;
 927   }
 928
 929   if (major_status & GSS_S_CONTINUE_NEEDED) {
 930      /* Some GSSAPI mechanism (eg GSI from Globus) may require multiple
 931       * iterations to establish authentication */
 932      ret = HTTP_UNAUTHORIZED;
 933      goto end;
 934   }
 935
 936   major_status = gss_display_name(&minor_status, client_name, &output_token, NULL);
 937   gss_release_name(&minor_status, &client_name);
 938   if (GSS_ERROR(major_status)) {
 939     log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 940                "%s", get_gss_error(r->pool, minor_status,
 941                                    "gss_export_name() failed"));
 942     ret = HTTP_INTERNAL_SERVER_ERROR;
 943     goto end;
 944   }
 945
 946   MK_AUTH_TYPE = "Negotiate";
 947   MK_USER = ap_pstrdup(r->pool, output_token.value);
 948
 949   if (conf->krb_save_credentials && delegated_cred != GSS_C_NO_CREDENTIAL)
 950      store_gss_creds(r, conf, (char *)output_token.value, delegated_cred);
 951
 952   gss_release_buffer(&minor_status, &output_token);
 953
 954   ret = OK;
 955
 956 end:
 957   if (delegated_cred)
 958      gss_release_cred(&minor_status, &delegated_cred);
 959
 960   if (output_token.length)
 961      gss_release_buffer(&minor_status, &output_token);
 962
 963   if (client_name != GSS_C_NO_NAME)
 964      gss_release_name(&minor_status, &client_name);
 965
 966   cleanup_gss_connection(gss_connection);
 967
 968   initial_return = ret;
 969   return ret;
 970 }
 971 #endif /* KRB5 */
 972
 973
 974 static void
 975 note_kerb_auth_failure(request_rec *r, const kerb_auth_config *conf,
 976                        int use_krb4, int use_krb5)
 977 {
 978    const char *auth_name = NULL;
 979    int set_basic = 0;
 980
 981    /* get the user realm specified in .htaccess */
 982    auth_name = ap_auth_name(r);
 983
 984    /* XXX should the WWW-Authenticate header be cleared first? */
 985 #ifdef KRB5
 986    if (use_krb5 && conf->krb_method_gssapi)
 987       ap_table_add(r->err_headers_out, "WWW-Authenticate", "GSS-Negotiate ");
 988    if (use_krb5 && conf->krb_method_k5pass) {
 989       ap_table_add(r->err_headers_out, "WWW-Authenticate",
 990                    ap_pstrcat(r->pool, "Basic realm=\"", auth_name, "\"", NULL));
 991       set_basic = 1;
 992    }
 993 #endif
 994
 995 #ifdef KRB4
 996    if (use_krb4 && conf->krb_method_k4pass && !set_basic)
 997       ap_table_add(r->err_headers_out, "WWW-Authenticate",
 998                    ap_pstrcat(r->pool, "Basic realm=\"", auth_name, "\"", NULL));
 999 #endif
1000 }
1001
1002 int kerb_authenticate_user(request_rec *r)
1003 {
1004    kerb_auth_config *conf =
1005       (kerb_auth_config *) ap_get_module_config(r->per_dir_config,
1006                                                 &auth_kerb_module);
1007    const char *auth_type = NULL;
1008    const char *auth_line = NULL;
1009    const char *type = NULL;
1010    int use_krb5 = 0, use_krb4 = 0;
1011    int ret;
1012
1013    /* get the type specified in .htaccess */
1014    type = ap_auth_type(r);
1015
1016    if (type && strcasecmp(type, "Kerberos") == 0)
1017       use_krb5 = use_krb4 = 1;
1018    else if(type && strcasecmp(type, "KerberosV5") == 0)
1019       use_krb4 = 0;
1020    else if(type && strcasecmp(type, "KerberosV4") == 0)
1021       use_krb5 = 0;
1022    else
1023       return DECLINED;
1024
1025    /* get what the user sent us in the HTTP header */
1026    auth_line = MK_TABLE_GET(r->headers_in, "Authorization");
1027    if (!auth_line) {
1028       note_kerb_auth_failure(r, conf, use_krb4, use_krb5);
1029       return HTTP_UNAUTHORIZED;
1030    }
1031    auth_type = ap_getword_white(r->pool, &auth_line);
1032
1033    ret = HTTP_UNAUTHORIZED;
1034
1035 #ifdef KRB5
1036    if (use_krb5 && conf->krb_method_gssapi &&
1037        strcasecmp(auth_type, "GSS-Negotiate") == 0) {
1038       ret = authenticate_user_gss(r, conf, auth_line);
1039    } else if (use_krb5 && conf->krb_method_k5pass &&
1040               strcasecmp(auth_type, "Basic") == 0) {
1041        ret = authenticate_user_krb5pwd(r, conf, auth_line);
1042    }
1043 #endif
1044
1045 #ifdef KRB4
1046    if (ret == HTTP_UNAUTHORIZED && use_krb4 && conf->krb_method_k4pass &&
1047        strcasecmp(auth_type, "Basic") == 0)
1048       ret = authenticate_user_krb4pwd(r, conf, auth_line);
1049 #endif
1050
1051    if (ret == HTTP_UNAUTHORIZED)
1052       note_kerb_auth_failure(r, conf, use_krb4, use_krb5);
1053
1054    return ret;
1055 }
1056
1057
1058 /***************************************************************************
1059  Module Setup/Configuration
1060  ***************************************************************************/
1061 #ifdef APXS1
1062 module MODULE_VAR_EXPORT auth_kerb_module = {
1063         STANDARD_MODULE_STUFF,
1064         NULL,                           /*      module initializer            */
1065         kerb_dir_create_config,         /*      per-directory config creator  */
1066         NULL,                           /*      per-directory config merger   */
1067         NULL,                           /*      per-server    config creator  */
1068         NULL,                           /*      per-server    config merger   */
1069         kerb_auth_cmds,                 /*      command table                 */
1070         NULL,                           /* [ 9] content handlers              */
1071         NULL,                           /* [ 2] URI-to-filename translation   */
1072         kerb_authenticate_user,         /* [ 5] check/validate user_id        */
1073         NULL,                           /* [ 6] check user_id is valid *here* */
1074         NULL,                           /* [ 4] check access by host address  */
1075         NULL,                           /* [ 7] MIME type checker/setter      */
1076         NULL,                           /* [ 8] fixups                        */
1077         NULL,                           /* [10] logger                        */
1078         NULL,                           /* [ 3] header parser                 */
1079         NULL,                           /*      process initialization        */
1080         NULL,                           /*      process exit/cleanup          */
1081         NULL                            /* [ 1] post read_request handling    */
1082 };
1083 #else
1084 void kerb_register_hooks(apr_pool_t *p)
1085 {
1086    ap_hook_check_user_id(kerb_authenticate_user, NULL, NULL, APR_HOOK_MIDDLE);
1087 }
1088
1089 module AP_MODULE_DECLARE_DATA auth_kerb_module =
1090 {
1091    STANDARD20_MODULE_STUFF,
1092    kerb_dir_create_config,      /* create per-dir    conf structures  */
1093    NULL,                        /* merge  per-dir    conf structures  */
1094    NULL,                        /* create per-server conf structures  */
1095    NULL,                        /* merge  per-server conf structures  */
1096    kerb_auth_cmds,              /* table of configuration directives  */
1097    kerb_register_hooks          /* register hooks                     */
1098 };
1099 #endif