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 #define MODAUTHKERB_VERSION "5.0-rc2"
  74
  75 #ifndef APXS1
  76 #include "ap_compat.h"
  77 #include "apr_strings.h"
  78 #endif
  79 #include "httpd.h"
  80 #include "http_config.h"
  81 #include "http_core.h"
  82 #include "http_log.h"
  83 #include "http_protocol.h"
  84 #include "http_request.h"
  85
  86 #ifdef KRB5
  87 #include <krb5.h>
  88 #ifdef HEIMDAL
  89 #  include <gssapi.h>
  90 #else
  91 #  include <gssapi/gssapi.h>
  92 #  include <gssapi/gssapi_generic.h>
  93 #  define GSS_C_NT_USER_NAME gss_nt_user_name
  94 #  define GSS_C_NT_HOSTBASED_SERVICE gss_nt_service_name
  95 #  define krb5_get_err_text(context,code) error_message(code)
  96 #endif
  97 #endif /* KRB5 */
  98
  99 #ifdef KRB4
 100 /*Prevent warning about closesocket redefinition (Apache's ap_config.h and
 101  * MIT Kerberos' port-sockets.h both define it as close) */
 102 #ifdef closesocket
 103 #  undef closesocket
 104 #endif
 105 #include <krb.h>
 106 #include <netdb.h> /* gethostbyname() */
 107 #endif /* KRB4 */
 108
 109 #ifdef APXS1
 110 module auth_kerb_module;
 111 #else
 112 module AP_MODULE_DECLARE_DATA auth_kerb_module;
 113 #endif
 114
 115 /***************************************************************************
 116  Macros To Ease Compatibility
 117  ***************************************************************************/
 118 #ifdef APXS1
 119 #define MK_POOL pool
 120 #define MK_TABLE_GET ap_table_get
 121 #define MK_TABLE_SET ap_table_set
 122 #define MK_TABLE_TYPE table
 123 #define MK_PSTRDUP ap_pstrdup
 124 #define MK_USER r->connection->user
 125 #define MK_AUTH_TYPE r->connection->ap_auth_type
 126 #define MK_ARRAY_HEADER array_header
 127 #else
 128 #define MK_POOL apr_pool_t
 129 #define MK_TABLE_GET apr_table_get
 130 #define MK_TABLE_SET apr_table_set
 131 #define MK_TABLE_TYPE apr_table_t
 132 #define MK_PSTRDUP apr_pstrdup
 133 #define MK_USER r->user
 134 #define MK_AUTH_TYPE r->ap_auth_type
 135 #define MK_ARRAY_HEADER apr_array_header_t
 136 #endif /* APXS1 */
 137
 138
 139 /***************************************************************************
 140  Auth Configuration Structure
 141  ***************************************************************************/
 142 typedef struct {
 143         char *krb_auth_realms;
 144         int krb_save_credentials;
 145 #ifdef KRB5
 146         char *krb_5_keytab;
 147         int krb_method_gssapi;
 148         int krb_method_k5pass;
 149 #endif
 150 #ifdef KRB4
 151         char *krb_4_srvtab;
 152         int krb_method_k4pass;
 153 #endif
 154 } kerb_auth_config;
 155
 156 static const char*
 157 krb5_save_realms(cmd_parms *cmd, kerb_auth_config *sec, char *arg);
 158
 159 #ifdef APXS1
 160 #define command(name, func, var, type, usage)           \
 161   { name, func,                                         \
 162     (void*)XtOffsetOf(kerb_auth_config, var),           \
 163     OR_AUTHCFG, type, usage }
 164 #else
 165 #define command(name, func, var, type, usage)           \
 166   AP_INIT_ ## type (name, func,                         \
 167         (void*)APR_XtOffsetOf(kerb_auth_config, var),   \
 168         OR_AUTHCFG, usage)
 169 #endif
 170
 171 static const command_rec kerb_auth_cmds[] = {
 172    command("KrbAuthRealms", krb5_save_realms, krb_auth_realms,
 173      RAW_ARGS, "Realms to attempt authentication against (can be multiple)."),
 174
 175    command("KrbAuthRealm", krb5_save_realms, krb_auth_realms,
 176      RAW_ARGS, "Alias for KrbAuthRealms."),
 177
 178    command("KrbSaveCredentials", ap_set_flag_slot, krb_save_credentials,
 179      FLAG, "Save and store credentials/tickets retrieved during auth."),
 180
 181 #ifdef KRB5
 182    command("Krb5Keytab", ap_set_file_slot, krb_5_keytab,
 183      TAKE1, "Location of Kerberos V5 keytab file."),
 184
 185    command("KrbMethodNegotiate", ap_set_flag_slot, krb_method_gssapi,
 186      FLAG, "Enable Negotiate authentication method."),
 187
 188    command("KrbMethodK5Pass", ap_set_flag_slot, krb_method_k5pass,
 189      FLAG, "Enable Kerberos V5 password authentication."),
 190 #endif
 191
 192 #ifdef KRB4
 193    command("Krb4Srvtab", ap_set_file_slot, krb_4_srvtab,
 194      TAKE1, "Location of Kerberos V4 srvtab file."),
 195
 196    command("KrbMethodK4Pass", ap_set_flag_slot, krb_method_k4pass,
 197      FLAG, "Enable Kerberos V4 password authentication."),
 198 #endif
 199
 200    { NULL }
 201 };
 202
 203 #ifdef KRB5
 204 typedef struct {
 205    gss_ctx_id_t context;
 206    gss_cred_id_t server_creds;
 207 } gss_connection_t;
 208
 209 static gss_connection_t *gss_connection = NULL;
 210 #endif
 211
 212
 213 /***************************************************************************
 214  Auth Configuration Initialization
 215  ***************************************************************************/
 216 static void *kerb_dir_create_config(MK_POOL *p, char *d)
 217 {
 218         kerb_auth_config *rec;
 219
 220         rec = (kerb_auth_config *) ap_pcalloc(p, sizeof(kerb_auth_config));
 221 #ifdef KRB5
 222         ((kerb_auth_config *)rec)->krb_method_k5pass = 1;
 223         ((kerb_auth_config *)rec)->krb_method_gssapi = 1;
 224 #endif
 225 #ifdef KRB4
 226         ((kerb_auth_config *)rec)->krb_method_k4pass = 1;
 227 #endif
 228         return rec;
 229 }
 230
 231 static const char*
 232 krb5_save_realms(cmd_parms *cmd, kerb_auth_config *sec, char *arg)
 233 {
 234    sec->krb_auth_realms= ap_pstrdup(cmd->pool, arg);
 235    return NULL;
 236 }
 237
 238 void log_rerror(const char *file, int line, int level, int status,
 239                 const request_rec *r, const char *fmt, ...)
 240 {
 241    char errstr[1024];
 242    va_list ap;
 243
 244    va_start(ap, fmt);
 245    vsnprintf(errstr, sizeof(errstr), fmt, ap);
 246    va_end(ap);
 247
 248 #ifdef APXS1
 249    ap_log_rerror(file, line, level, r, "%s", errstr);
 250 #else
 251    ap_log_rerror(file, line, level, status, r, "%s", errstr);
 252 #endif
 253 }
 254
 255 #ifdef KRB4
 256 /***************************************************************************
 257  Username/Password Validation for Krb4
 258  ***************************************************************************/
 259 static int
 260 verify_krb4_user(request_rec *r, char *name, char *instance, char *realm,
 261                  char *password, char *linstance, char *srvtab)
 262 {
 263    int ret;
 264    char *phost;
 265    unsigned long addr;
 266    struct hostent *hp;
 267    const char *hostname;
 268    KTEXT_ST ticket;
 269    AUTH_DAT authdata;
 270    char lrealm[REALM_SZ];
 271
 272    ret = krb_get_pw_in_tkt(name, instance, realm, "krbtgt", realm,
 273                            DEFAULT_TKT_LIFE, password);
 274    if (ret)
 275       /* log(krb_err_txt[ret]) */
 276       return ret;
 277
 278    hostname = ap_get_server_name(r);
 279
 280    hp = gethostbyname(hostname);
 281    if (hp == NULL) {
 282       dest_tkt();
 283       return h_errno;
 284    }
 285    memcpy(&addr, hp->h_addr, sizeof(addr));
 286
 287    phost = krb_get_phost((char *)hostname);
 288
 289    krb_get_lrealm(lrealm, 1);
 290
 291    ret = krb_mk_req(&ticket, linstance, phost, lrealm, 0);
 292    if (ret) {
 293       dest_tkt();
 294       return ret;
 295    }
 296
 297    ret = krb_rd_req(&ticket, linstance, phost, addr, &authdata, srvtab);
 298    if (ret)
 299       dest_tkt();
 300
 301    return ret;
 302 }
 303
 304 static int
 305 krb4_cache_cleanup(void *data)
 306 {
 307    char *tkt_file = (char *) data;
 308
 309    krb_set_tkt_string(tkt_file);
 310    dest_tkt();
 311    return OK;
 312 }
 313
 314 static int
 315 authenticate_user_krb4pwd(request_rec *r,
 316                           kerb_auth_config *conf,
 317                           const char *auth_line)
 318 {
 319    int ret;
 320    const char *sent_pw;
 321    const char *sent_name;
 322    char *sent_instance;
 323    char tkt_file[32];
 324    char *tkt_file_p = NULL;
 325    int fd;
 326    const char *realms;
 327    const char *realm;
 328    char *user;
 329    char lrealm[REALM_SZ];
 330
 331    sent_pw = ap_pbase64decode(r->pool, auth_line);
 332    sent_name = ap_getword (r->pool, &sent_pw, ':');
 333
 334    /* do not allow user to override realm setting of server */
 335    if (strchr(sent_name, '@')) {
 336       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 337                  "specifying realm in user name is prohibited");
 338       return HTTP_UNAUTHORIZED;
 339    }
 340
 341    sent_instance = strchr(sent_name, '.');
 342    if (sent_instance)
 343       *sent_instance++ = '\0';
 344
 345    snprintf(tkt_file, sizeof(tkt_file), "/tmp/apache_tkt_XXXXXX");
 346    fd = mkstemp(tkt_file);
 347    if (fd < 0) {
 348       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 349                  "Cannot create krb4 ccache: mkstemp() failed: %s",
 350                  strerror(errno));
 351       return HTTP_INTERNAL_SERVER_ERROR;
 352    }
 353
 354    tkt_file_p = ap_pstrdup(r->pool, tkt_file);
 355    ap_register_cleanup(r->pool, tkt_file_p,
 356                        krb4_cache_cleanup, ap_null_cleanup);
 357
 358    krb_set_tkt_string(tkt_file);
 359
 360    realms = conf->krb_auth_realms;
 361    do {
 362       memset(lrealm, 0, sizeof(lrealm));
 363       realm = NULL;
 364       if (realms)
 365          realm = ap_getword_white(r->pool, &realms);
 366
 367       if (realm == NULL) {
 368          ret = krb_get_lrealm(lrealm, 1);
 369          realm = lrealm;
 370       }
 371       if (realm == NULL || *realm == '\0')
 372          break;
 373
 374       ret = verify_krb4_user(r, (char *)sent_name,
 375                              (sent_instance) ? sent_instance : "",
 376                              (char *)realm, (char *)sent_pw, "khttp",
 377                              conf->krb_4_srvtab);
 378       if (ret == 0)
 379          break;
 380    } while (realms && *realms);
 381
 382    if (ret) {
 383       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 384                  "Verifying krb4 password failed (%d)", ret);
 385       ret = HTTP_UNAUTHORIZED;
 386       goto end;
 387    }
 388
 389    user = ap_pstrdup(r->pool, sent_name);
 390    if (sent_instance)
 391       user = ap_pstrcat(r->pool, user, ".", sent_instance, NULL);
 392    user = ap_pstrcat(r->pool, user, "@", realm, NULL);
 393
 394    MK_USER = user;
 395    MK_AUTH_TYPE = "Basic";
 396    ap_table_setn(r->subprocess_env, "KRBTKFILE", tkt_file_p);
 397
 398    if (!conf->krb_save_credentials)
 399       krb4_cache_cleanup(tkt_file);
 400
 401 end:
 402    if (ret)
 403       krb4_cache_cleanup(tkt_file);
 404    close(fd);
 405    tf_close();
 406
 407    return ret;
 408 }
 409 #endif /* KRB4 */
 410
 411 #ifdef KRB5
 412 /***************************************************************************
 413  Username/Password Validation for Krb5
 414  ***************************************************************************/
 415 /* Inspired by krb5_verify_user from Heimdal */
 416 static krb5_error_code
 417 verify_krb5_user(request_rec *r, krb5_context context, krb5_principal principal,
 418                  krb5_ccache ccache, const char *password, const char *service,
 419                  krb5_keytab keytab)
 420 {
 421    krb5_creds creds;
 422    krb5_principal server = NULL;
 423    krb5_error_code ret;
 424    krb5_verify_init_creds_opt opt;
 425
 426    memset(&creds, 0, sizeof(creds));
 427
 428    ret = krb5_get_init_creds_password(context, &creds, principal,
 429                                       (char *)password, krb5_prompter_posix,
 430                                       NULL, 0, NULL, NULL);
 431    if (ret)
 432       return ret;
 433
 434    ret = krb5_sname_to_principal(context, ap_get_server_name(r), service,
 435                                  KRB5_NT_SRV_HST, &server);
 436    if (ret)
 437       goto end;
 438
 439    krb5_verify_init_creds_opt_init(&opt);
 440    krb5_verify_init_creds_opt_set_ap_req_nofail(&opt, 1);
 441
 442    ret = krb5_verify_init_creds(context, &creds, server, keytab, NULL, &opt);
 443    if (ret)
 444       goto end;
 445
 446    if (ccache) {
 447       ret = krb5_cc_initialize(context, ccache, principal);
 448       if (ret == 0)
 449          ret = krb5_cc_store_cred(context, ccache, &creds);
 450    }
 451
 452 end:
 453    krb5_free_cred_contents(context, &creds);
 454    if (server)
 455       krb5_free_principal(context, server);
 456    return ret;
 457 }
 458
 459 static int
 460 krb5_cache_cleanup(void *data)
 461 {
 462    krb5_context context;
 463    krb5_ccache  cache;
 464    krb5_error_code problem;
 465    char *cache_name = (char *) data;
 466
 467    problem = krb5_init_context(&context);
 468    if (problem) {
 469       /* ap_log_error(APLOG_MARK, APLOG_ERR, 0, NULL, "krb5_init_context() failed"); */
 470       return HTTP_INTERNAL_SERVER_ERROR;
 471    }
 472
 473    problem = krb5_cc_resolve(context, cache_name, &cache);
 474    if (problem) {
 475       /* log_error(APLOG_MARK, APLOG_ERR, 0, NULL,
 476                 "krb5_cc_resolve() failed (%s: %s)",
 477                 cache_name, krb5_get_err_text(context, problem)); */
 478       return HTTP_INTERNAL_SERVER_ERROR;
 479    }
 480
 481    krb5_cc_destroy(context, cache);
 482    krb5_free_context(context);
 483    return OK;
 484 }
 485
 486 static int
 487 create_krb5_ccache(krb5_context kcontext,
 488                    request_rec *r,
 489                    kerb_auth_config *conf,
 490                    krb5_principal princ,
 491                    krb5_ccache *ccache)
 492 {
 493    char *ccname;
 494    krb5_error_code problem;
 495    int ret;
 496    krb5_ccache tmp_ccache = NULL;
 497
 498 #ifdef HEIMDAL
 499    problem = krb5_cc_gen_new(kcontext, &krb5_fcc_ops, &tmp_ccache);
 500 #else
 501    problem = krb5_fcc_generate_new(kcontext, &tmp_ccache);
 502    /* krb5_fcc_generate_new() doesn't set KRB5_TC_OPENCLOSE, which makes
 503       krb5_cc_initialize() fail */
 504    krb5_fcc_set_flags(kcontext, tmp_ccache, KRB5_TC_OPENCLOSE);
 505 #endif
 506    if (problem) {
 507       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 508                  "Cannot create file for new krb5 ccache: %s",
 509                  krb5_get_err_text(kcontext, problem));
 510       ret = HTTP_INTERNAL_SERVER_ERROR;
 511       goto end;
 512    }
 513
 514    ccname = ap_pstrdup(r->pool, krb5_cc_get_name(kcontext, tmp_ccache));
 515
 516    problem = krb5_cc_initialize(kcontext, tmp_ccache, princ);
 517    if (problem) {
 518       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 519                  "Cannot initialize krb5 ccache %s: krb5_cc_initialize() failed: %s",
 520                  ccname, krb5_get_err_text(kcontext, problem));
 521       ret = HTTP_INTERNAL_SERVER_ERROR;
 522       goto end;
 523    }
 524
 525    ap_table_setn(r->subprocess_env, "KRB5CCNAME", ccname);
 526    ap_register_cleanup(r->pool, ccname,
 527                        krb5_cache_cleanup, ap_null_cleanup);
 528
 529    *ccache = tmp_ccache;
 530    tmp_ccache = NULL;
 531
 532    ret = OK;
 533
 534 end:
 535    if (tmp_ccache)
 536       krb5_cc_destroy(kcontext, tmp_ccache);
 537
 538    return ret;
 539 }
 540
 541 static int
 542 store_krb5_creds(krb5_context kcontext,
 543                  request_rec *r,
 544                  kerb_auth_config *conf,
 545                  krb5_ccache delegated_cred)
 546 {
 547    char errstr[1024];
 548    krb5_error_code problem;
 549    krb5_principal princ;
 550    krb5_ccache ccache;
 551    int ret;
 552
 553    problem = krb5_cc_get_principal(kcontext, delegated_cred, &princ);
 554    if (problem) {
 555       snprintf(errstr, sizeof(errstr), "krb5_cc_get_principal() failed: %s",
 556                krb5_get_err_text(kcontext, problem));
 557       return HTTP_INTERNAL_SERVER_ERROR;
 558    }
 559
 560    ret = create_krb5_ccache(kcontext, r, conf, princ, &ccache);
 561    if (ret) {
 562       krb5_free_principal(kcontext, princ);
 563       return ret;
 564    }
 565
 566 #ifdef HEIMDAL
 567    problem = krb5_cc_copy_cache(kcontext, delegated_cred, ccache);
 568 #else
 569    problem = krb5_cc_copy_creds(kcontext, delegated_cred, ccache);
 570 #endif
 571    krb5_free_principal(kcontext, princ);
 572    if (problem) {
 573       snprintf(errstr, sizeof(errstr), "Failed to store credentials: %s",
 574                krb5_get_err_text(kcontext, problem));
 575       krb5_cc_destroy(kcontext, ccache);
 576       return HTTP_INTERNAL_SERVER_ERROR;
 577    }
 578
 579    krb5_cc_close(kcontext, ccache);
 580    return OK;
 581 }
 582
 583
 584 int authenticate_user_krb5pwd(request_rec *r,
 585                               kerb_auth_config *conf,
 586                               const char *auth_line)
 587 {
 588    const char      *sent_pw = NULL;
 589    const char      *sent_name = NULL;
 590    const char      *realms = NULL;
 591    krb5_context    kcontext = NULL;
 592    krb5_error_code code;
 593    krb5_principal  client = NULL;
 594    krb5_ccache     ccache = NULL;
 595    krb5_keytab     keytab = NULL;
 596    int             ret;
 597    char *name = NULL;
 598
 599    code = krb5_init_context(&kcontext);
 600    if (code) {
 601       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 602                  "Cannot initialize Kerberos5 context (%d)", code);
 603       return HTTP_INTERNAL_SERVER_ERROR;
 604    }
 605
 606    sent_pw = ap_pbase64decode(r->pool, auth_line);
 607    sent_name = ap_getword (r->pool, &sent_pw, ':');
 608    /* do not allow user to override realm setting of server */
 609    if (strchr(sent_name, '@')) {
 610       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 611                  "specifying realm in user name is prohibited");
 612       ret = HTTP_UNAUTHORIZED;
 613       goto end;
 614    }
 615
 616 #ifdef HEIMDAL
 617    code = krb5_cc_gen_new(kcontext, &krb5_mcc_ops, &ccache);
 618 #else
 619    code = krb5_mcc_generate_new(kcontext, &ccache);
 620 #endif
 621    if (code) {
 622       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 623                  "Cannot generate new ccache: %s",
 624                  krb5_get_err_text(kcontext, code));
 625       ret = HTTP_INTERNAL_SERVER_ERROR;
 626       goto end;
 627    }
 628
 629    if (conf->krb_5_keytab)
 630       krb5_kt_resolve(kcontext, conf->krb_5_keytab, &keytab);
 631       /* setenv("KRB5_KTNAME", conf->krb_5_keytab, 1); */
 632
 633    realms = conf->krb_auth_realms;
 634    do {
 635       if (realms && (code = krb5_set_default_realm(kcontext,
 636                                            ap_getword_white(r->pool, &realms))))
 637          continue;
 638
 639       if (client) {
 640          krb5_free_principal(kcontext, client);
 641          client = NULL;
 642       }
 643       code = krb5_parse_name(kcontext, sent_name, &client);
 644       if (code)
 645          continue;
 646
 647       code = verify_krb5_user(r, kcontext, client, ccache, sent_pw, "khttp",
 648                               keytab);
 649       if (code == 0)
 650          break;
 651
 652       /* ap_getword_white() used above shifts the parameter, so it's not
 653          needed to touch the realms variable */
 654    } while (realms && *realms);
 655
 656    memset((char *)sent_pw, 0, strlen(sent_pw));
 657
 658    if (code) {
 659       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 660                  "Verifying krb5 password failed: %s",
 661                  krb5_get_err_text(kcontext, code));
 662       ret = HTTP_UNAUTHORIZED;
 663       goto end;
 664    }
 665
 666    code = krb5_unparse_name(kcontext, client, &name);
 667    if (code) {
 668       log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "krb5_unparse_name() failed: %s",
 669                  krb5_get_err_text(kcontext, code));
 670       ret = HTTP_UNAUTHORIZED;
 671       goto end;
 672    }
 673    MK_USER = ap_pstrdup (r->pool, name);
 674    MK_AUTH_TYPE = "Basic";
 675    free(name);
 676
 677    if (conf->krb_save_credentials)
 678       store_krb5_creds(kcontext, r, conf, ccache);
 679
 680    ret = OK;
 681
 682 end:
 683    if (client)
 684       krb5_free_principal(kcontext, client);
 685    if (ccache)
 686       krb5_cc_destroy(kcontext, ccache);
 687    if (keytab)
 688       krb5_kt_close(kcontext, keytab);
 689    krb5_free_context(kcontext);
 690
 691    return ret;
 692 }
 693
 694 /*********************************************************************
 695  * GSSAPI Authentication
 696  ********************************************************************/
 697
 698 static const char *
 699 get_gss_error(MK_POOL *p, OM_uint32 error_status, char *prefix)
 700 {
 701    OM_uint32 maj_stat, min_stat;
 702    OM_uint32 msg_ctx = 0;
 703    gss_buffer_desc status_string;
 704    char buf[1024];
 705    size_t len;
 706
 707    snprintf(buf, sizeof(buf), "%s", prefix);
 708    len = strlen(buf);
 709    do {
 710       maj_stat = gss_display_status (&min_stat,
 711                                      error_status,
 712                                      GSS_C_MECH_CODE,
 713                                      GSS_C_NO_OID,
 714                                      &msg_ctx,
 715                                      &status_string);
 716       if (sizeof(buf) > len + status_string.length + 1) {
 717          sprintf(buf+len, ": %s", (char*) status_string.value);
 718          len += status_string.length;
 719       }
 720       gss_release_buffer(&min_stat, &status_string);
 721    } while (!GSS_ERROR(maj_stat) && msg_ctx != 0);
 722
 723    return (ap_pstrdup(p, buf));
 724 }
 725
 726 static int
 727 cleanup_gss_connection(void *data)
 728 {
 729    OM_uint32 minor_status;
 730    gss_connection_t *gss_conn = (gss_connection_t *)data;
 731
 732    if (data == NULL)
 733       return OK;
 734    if (gss_conn->context != GSS_C_NO_CONTEXT)
 735       gss_delete_sec_context(&minor_status, &gss_conn->context,
 736                              GSS_C_NO_BUFFER);
 737    if (gss_conn->server_creds != GSS_C_NO_CREDENTIAL)
 738       gss_release_cred(&minor_status, &gss_conn->server_creds);
 739
 740    gss_connection = NULL;
 741
 742    return OK;
 743 }
 744
 745 static int
 746 store_gss_creds(request_rec *r, kerb_auth_config *conf, char *princ_name,
 747                 gss_cred_id_t delegated_cred)
 748 {
 749    OM_uint32 maj_stat, min_stat;
 750    krb5_principal princ = NULL;
 751    krb5_ccache ccache = NULL;
 752    krb5_error_code problem;
 753    krb5_context context;
 754    int ret = HTTP_INTERNAL_SERVER_ERROR;
 755
 756    problem = krb5_init_context(&context);
 757    if (problem) {
 758       log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "Cannot initialize krb5 context");
 759       return HTTP_INTERNAL_SERVER_ERROR;
 760    }
 761
 762    problem = krb5_parse_name(context, princ_name, &princ);
 763    if (problem) {
 764       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 765          "Cannot parse delegated username (%s)", krb5_get_err_text(context, problem));
 766       goto end;
 767    }
 768
 769    problem = create_krb5_ccache(context, r, conf, princ, &ccache);
 770    if (problem) {
 771       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 772          "Cannot create krb5 ccache (%s)", krb5_get_err_text(context, problem));
 773       goto end;
 774    }
 775
 776    maj_stat = gss_krb5_copy_ccache(&min_stat, delegated_cred, ccache);
 777    if (GSS_ERROR(maj_stat)) {
 778       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 779          "Cannot store delegated credential (%s)",
 780          get_gss_error(r->pool, min_stat, "gss_krb5_copy_ccache"));
 781       goto end;
 782    }
 783
 784    krb5_cc_close(context, ccache);
 785    ccache = NULL;
 786    ret = 0;
 787
 788 end:
 789    if (princ)
 790       krb5_free_principal(context, princ);
 791    if (ccache)
 792       krb5_cc_destroy(context, ccache);
 793    krb5_free_context(context);
 794    return ret;
 795 }
 796
 797 static int
 798 get_gss_creds(request_rec *r,
 799               kerb_auth_config *conf,
 800               gss_cred_id_t *server_creds)
 801 {
 802    gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
 803    OM_uint32 major_status, minor_status, minor_status2;
 804    gss_name_t server_name = GSS_C_NO_NAME;
 805    char buf[1024];
 806
 807    snprintf(buf, sizeof(buf), "%s/%s", "khttp", ap_get_server_name(r));
 808
 809    input_token.value = buf;
 810    input_token.length = strlen(buf) + 1;
 811
 812    major_status = gss_import_name(&minor_status, &input_token,
 813                                   GSS_C_NT_USER_NAME,
 814                                   &server_name);
 815    if (GSS_ERROR(major_status)) {
 816       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 817                  "%s", get_gss_error(r->pool, minor_status,
 818                  "gss_import_name() failed"));
 819       return HTTP_INTERNAL_SERVER_ERROR;
 820    }
 821
 822    major_status = gss_acquire_cred(&minor_status, server_name, GSS_C_INDEFINITE,
 823                                    GSS_C_NO_OID_SET, GSS_C_ACCEPT,
 824                                    server_creds, NULL, NULL);
 825    gss_release_name(&minor_status2, &server_name);
 826    if (GSS_ERROR(major_status)) {
 827       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 828                  "%s", get_gss_error(r->pool, minor_status,
 829                                      "gss_acquire_cred() failed"));
 830       return HTTP_INTERNAL_SERVER_ERROR;
 831    }
 832
 833    return 0;
 834 }
 835
 836 static int
 837 authenticate_user_gss(request_rec *r,
 838                       kerb_auth_config *conf,
 839                       const char *auth_line)
 840 {
 841   OM_uint32 major_status, minor_status, minor_status2;
 842   gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
 843   gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER;
 844   const char *auth_param = NULL;
 845   int ret;
 846   gss_name_t client_name = GSS_C_NO_NAME;
 847   gss_cred_id_t delegated_cred = GSS_C_NO_CREDENTIAL;
 848   static int initial_return = HTTP_UNAUTHORIZED;
 849
 850   /* needed to work around replay caches */
 851   if (!ap_is_initial_req(r))
 852      return initial_return;
 853   initial_return = HTTP_UNAUTHORIZED;
 854
 855   if (gss_connection == NULL) {
 856      gss_connection = ap_pcalloc(r->connection->pool, sizeof(*gss_connection));
 857      if (gss_connection == NULL) {
 858         log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 859                    "ap_pcalloc() failed (not enough memory)");
 860         ret = HTTP_INTERNAL_SERVER_ERROR;
 861         goto end;
 862      }
 863      memset(gss_connection, 0, sizeof(*gss_connection));
 864      ap_register_cleanup(r->connection->pool, gss_connection, cleanup_gss_connection, ap_null_cleanup);
 865   }
 866
 867   if (conf->krb_5_keytab)
 868      setenv("KRB5_KTNAME", conf->krb_5_keytab, 1);
 869
 870   if (gss_connection->server_creds == GSS_C_NO_CREDENTIAL) {
 871      ret = get_gss_creds(r, conf, &gss_connection->server_creds);
 872      if (ret)
 873         goto end;
 874   }
 875
 876   /* ap_getword() shifts parameter */
 877   auth_param = ap_getword_white(r->pool, &auth_line);
 878   if (auth_param == NULL) {
 879      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 880                 "No Authorization parameter in request from client");
 881      ret = HTTP_UNAUTHORIZED;
 882      goto end;
 883   }
 884
 885   input_token.length = ap_base64decode_len(auth_param) + 1;
 886   input_token.value = ap_pcalloc(r->connection->pool, input_token.length);
 887   if (input_token.value == NULL) {
 888      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 889                 "ap_pcalloc() failed (not enough memory)");
 890      ret = HTTP_INTERNAL_SERVER_ERROR;
 891      goto end;
 892   }
 893   input_token.length = ap_base64decode(input_token.value, auth_param);
 894
 895 #if 0
 896   major_status = gss_accept_sec_context(
 897 #else
 898   major_status = gss_accept_sec_context_spnego(
 899 #endif
 900                                         &minor_status,
 901                                         &gss_connection->context,
 902                                         gss_connection->server_creds,
 903                                         &input_token,
 904                                         GSS_C_NO_CHANNEL_BINDINGS,
 905                                         &client_name,
 906                                         NULL,
 907                                         &output_token,
 908                                         NULL,
 909                                         NULL,
 910                                         &delegated_cred);
 911   if (output_token.length) {
 912      char *token = NULL;
 913      size_t len;
 914
 915      len = ap_base64encode_len(output_token.length) + 1;
 916      token = ap_pcalloc(r->connection->pool, len + 1);
 917      if (token == NULL) {
 918         log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 919                    "ap_pcalloc() failed (not enough memory)");
 920         ret = HTTP_INTERNAL_SERVER_ERROR;
 921         gss_release_buffer(&minor_status2, &output_token);
 922         goto end;
 923      }
 924      ap_base64encode(token, output_token.value, output_token.length);
 925      token[len] = '\0';
 926      ap_table_set(r->err_headers_out, "WWW-Authenticate",
 927                   ap_pstrcat(r->pool, "Negotiate ", token, NULL));
 928      gss_release_buffer(&minor_status2, &output_token);
 929   }
 930
 931   if (GSS_ERROR(major_status)) {
 932      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 933                 "%s", get_gss_error(r->pool, minor_status,
 934                                     "gss_accept_sec_context() failed"));
 935      ret = HTTP_UNAUTHORIZED;
 936      goto end;
 937   }
 938
 939   if (major_status & GSS_S_CONTINUE_NEEDED) {
 940      /* Some GSSAPI mechanism (eg GSI from Globus) may require multiple
 941       * iterations to establish authentication */
 942      ret = HTTP_UNAUTHORIZED;
 943      goto end;
 944   }
 945
 946   major_status = gss_display_name(&minor_status, client_name, &output_token, NULL);
 947   gss_release_name(&minor_status, &client_name);
 948   if (GSS_ERROR(major_status)) {
 949     log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 950                "%s", get_gss_error(r->pool, minor_status,
 951                                    "gss_export_name() failed"));
 952     ret = HTTP_INTERNAL_SERVER_ERROR;
 953     goto end;
 954   }
 955
 956   MK_AUTH_TYPE = "Negotiate";
 957   MK_USER = ap_pstrdup(r->pool, output_token.value);
 958
 959   if (conf->krb_save_credentials && delegated_cred != GSS_C_NO_CREDENTIAL)
 960      store_gss_creds(r, conf, (char *)output_token.value, delegated_cred);
 961
 962   gss_release_buffer(&minor_status, &output_token);
 963
 964   ret = OK;
 965
 966 end:
 967   if (delegated_cred)
 968      gss_release_cred(&minor_status, &delegated_cred);
 969
 970   if (output_token.length)
 971      gss_release_buffer(&minor_status, &output_token);
 972
 973   if (client_name != GSS_C_NO_NAME)
 974      gss_release_name(&minor_status, &client_name);
 975
 976   cleanup_gss_connection(gss_connection);
 977
 978   initial_return = ret;
 979   return ret;
 980 }
 981 #endif /* KRB5 */
 982
 983
 984 static void
 985 note_kerb_auth_failure(request_rec *r, const kerb_auth_config *conf,
 986                        int use_krb4, int use_krb5)
 987 {
 988    const char *auth_name = NULL;
 989    int set_basic = 0;
 990
 991    /* get the user realm specified in .htaccess */
 992    auth_name = ap_auth_name(r);
 993
 994    /* XXX should the WWW-Authenticate header be cleared first? */
 995 #ifdef KRB5
 996    if (use_krb5 && conf->krb_method_gssapi)
 997       ap_table_add(r->err_headers_out, "WWW-Authenticate", "Negotiate ");
 998    if (use_krb5 && conf->krb_method_k5pass) {
 999       ap_table_add(r->err_headers_out, "WWW-Authenticate",
1000                    ap_pstrcat(r->pool, "Basic realm=\"", auth_name, "\"", NULL));
1001       set_basic = 1;
1002    }
1003 #endif
1004
1005 #ifdef KRB4
1006    if (use_krb4 && conf->krb_method_k4pass && !set_basic)
1007       ap_table_add(r->err_headers_out, "WWW-Authenticate",
1008                    ap_pstrcat(r->pool, "Basic realm=\"", auth_name, "\"", NULL));
1009 #endif
1010 }
1011
1012 int kerb_authenticate_user(request_rec *r)
1013 {
1014    kerb_auth_config *conf =
1015       (kerb_auth_config *) ap_get_module_config(r->per_dir_config,
1016                                                 &auth_kerb_module);
1017    const char *auth_type = NULL;
1018    const char *auth_line = NULL;
1019    const char *type = NULL;
1020    int use_krb5 = 0, use_krb4 = 0;
1021    int ret;
1022
1023    /* get the type specified in .htaccess */
1024    type = ap_auth_type(r);
1025
1026    if (type && strcasecmp(type, "Kerberos") == 0)
1027       use_krb5 = use_krb4 = 1;
1028    else if(type && strcasecmp(type, "KerberosV5") == 0)
1029       use_krb4 = 0;
1030    else if(type && strcasecmp(type, "KerberosV4") == 0)
1031       use_krb5 = 0;
1032    else
1033       return DECLINED;
1034
1035    /* get what the user sent us in the HTTP header */
1036    auth_line = MK_TABLE_GET(r->headers_in, "Authorization");
1037    if (!auth_line) {
1038       note_kerb_auth_failure(r, conf, use_krb4, use_krb5);
1039       return HTTP_UNAUTHORIZED;
1040    }
1041    auth_type = ap_getword_white(r->pool, &auth_line);
1042
1043    ret = HTTP_UNAUTHORIZED;
1044
1045 #ifdef KRB5
1046    if (use_krb5 && conf->krb_method_gssapi &&
1047        strcasecmp(auth_type, "Negotiate") == 0) {
1048       ret = authenticate_user_gss(r, conf, auth_line);
1049    } else if (use_krb5 && conf->krb_method_k5pass &&
1050               strcasecmp(auth_type, "Basic") == 0) {
1051        ret = authenticate_user_krb5pwd(r, conf, auth_line);
1052    }
1053 #endif
1054
1055 #ifdef KRB4
1056    if (ret == HTTP_UNAUTHORIZED && use_krb4 && conf->krb_method_k4pass &&
1057        strcasecmp(auth_type, "Basic") == 0)
1058       ret = authenticate_user_krb4pwd(r, conf, auth_line);
1059 #endif
1060
1061    if (ret == HTTP_UNAUTHORIZED)
1062       note_kerb_auth_failure(r, conf, use_krb4, use_krb5);
1063
1064    return ret;
1065 }
1066
1067
1068 /***************************************************************************
1069  Module Setup/Configuration
1070  ***************************************************************************/
1071 #ifdef APXS1
1072 module MODULE_VAR_EXPORT auth_kerb_module = {
1073         STANDARD_MODULE_STUFF,
1074         NULL,                           /*      module initializer            */
1075         kerb_dir_create_config,         /*      per-directory config creator  */
1076         NULL,                           /*      per-directory config merger   */
1077         NULL,                           /*      per-server    config creator  */
1078         NULL,                           /*      per-server    config merger   */
1079         kerb_auth_cmds,                 /*      command table                 */
1080         NULL,                           /* [ 9] content handlers              */
1081         NULL,                           /* [ 2] URI-to-filename translation   */
1082         kerb_authenticate_user,         /* [ 5] check/validate user_id        */
1083         NULL,                           /* [ 6] check user_id is valid *here* */
1084         NULL,                           /* [ 4] check access by host address  */
1085         NULL,                           /* [ 7] MIME type checker/setter      */
1086         NULL,                           /* [ 8] fixups                        */
1087         NULL,                           /* [10] logger                        */
1088         NULL,                           /* [ 3] header parser                 */
1089         NULL,                           /*      process initialization        */
1090         NULL,                           /*      process exit/cleanup          */
1091         NULL                            /* [ 1] post read_request handling    */
1092 };
1093 #else
1094 static int
1095 kerb_init_handler(apr_pool_t *p, apr_pool_t *plog,
1096                   apr_pool_t *ptemp, server_rec *s)
1097 {
1098    ap_add_version_component(p, "mod_auth_kerb/" MODAUTHKERB_VERSION);
1099    return OK;
1100 }
1101
1102 void kerb_register_hooks(apr_pool_t *p)
1103 {
1104    ap_hook_post_config(kerb_init_handler, NULL, NULL, APR_HOOK_MIDDLE);
1105    ap_hook_check_user_id(kerb_authenticate_user, NULL, NULL, APR_HOOK_MIDDLE);
1106 }
1107
1108 module AP_MODULE_DECLARE_DATA auth_kerb_module =
1109 {
1110    STANDARD20_MODULE_STUFF,
1111    kerb_dir_create_config,      /* create per-dir    conf structures  */
1112    NULL,                        /* merge  per-dir    conf structures  */
1113    NULL,                        /* create per-server conf structures  */
1114    NULL,                        /* merge  per-server conf structures  */
1115    kerb_auth_cmds,              /* table of configuration directives  */
1116    kerb_register_hooks          /* register hooks                     */
1117 };
1118 #endif