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
 632    realms = conf->krb_auth_realms;
 633    do {
 634       if (realms && (code = krb5_set_default_realm(kcontext,
 635                                            ap_getword_white(r->pool, &realms))))
 636          continue;
 637
 638       if (client) {
 639          krb5_free_principal(kcontext, client);
 640          client = NULL;
 641       }
 642       code = krb5_parse_name(kcontext, sent_name, &client);
 643       if (code)
 644          continue;
 645
 646       code = verify_krb5_user(r, kcontext, client, ccache, sent_pw, "khttp",
 647                               keytab);
 648       if (code == 0)
 649          break;
 650
 651       /* ap_getword_white() used above shifts the parameter, so it's not
 652          needed to touch the realms variable */
 653    } while (realms && *realms);
 654
 655    memset((char *)sent_pw, 0, strlen(sent_pw));
 656
 657    if (code) {
 658       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 659                  "Verifying krb5 password failed: %s",
 660                  krb5_get_err_text(kcontext, code));
 661       ret = HTTP_UNAUTHORIZED;
 662       goto end;
 663    }
 664
 665    code = krb5_unparse_name(kcontext, client, &name);
 666    if (code) {
 667       log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "krb5_unparse_name() failed: %s",
 668                  krb5_get_err_text(kcontext, code));
 669       ret = HTTP_UNAUTHORIZED;
 670       goto end;
 671    }
 672    MK_USER = ap_pstrdup (r->pool, name);
 673    MK_AUTH_TYPE = "Basic";
 674    free(name);
 675
 676    if (conf->krb_save_credentials)
 677       store_krb5_creds(kcontext, r, conf, ccache);
 678
 679    ret = OK;
 680
 681 end:
 682    if (client)
 683       krb5_free_principal(kcontext, client);
 684    if (ccache)
 685       krb5_cc_destroy(kcontext, ccache);
 686    if (keytab)
 687       krb5_kt_close(kcontext, keytab);
 688    krb5_free_context(kcontext);
 689
 690    return ret;
 691 }
 692
 693 /*********************************************************************
 694  * GSSAPI Authentication
 695  ********************************************************************/
 696
 697 static const char *
 698 get_gss_error(MK_POOL *p, OM_uint32 error_status, char *prefix)
 699 {
 700    OM_uint32 maj_stat, min_stat;
 701    OM_uint32 msg_ctx = 0;
 702    gss_buffer_desc status_string;
 703    char buf[1024];
 704    size_t len;
 705
 706    snprintf(buf, sizeof(buf), "%s", prefix);
 707    len = strlen(buf);
 708    do {
 709       maj_stat = gss_display_status (&min_stat,
 710                                      error_status,
 711                                      GSS_C_MECH_CODE,
 712                                      GSS_C_NO_OID,
 713                                      &msg_ctx,
 714                                      &status_string);
 715       if (sizeof(buf) > len + status_string.length + 1) {
 716          sprintf(buf+len, ": %s", (char*) status_string.value);
 717          len += status_string.length;
 718       }
 719       gss_release_buffer(&min_stat, &status_string);
 720    } while (!GSS_ERROR(maj_stat) && msg_ctx != 0);
 721
 722    return (ap_pstrdup(p, buf));
 723 }
 724
 725 static int
 726 cleanup_gss_connection(void *data)
 727 {
 728    OM_uint32 minor_status;
 729    gss_connection_t *gss_conn = (gss_connection_t *)data;
 730
 731    if (data == NULL)
 732       return OK;
 733    if (gss_conn->context != GSS_C_NO_CONTEXT)
 734       gss_delete_sec_context(&minor_status, &gss_conn->context,
 735                              GSS_C_NO_BUFFER);
 736    if (gss_conn->server_creds != GSS_C_NO_CREDENTIAL)
 737       gss_release_cred(&minor_status, &gss_conn->server_creds);
 738
 739    gss_connection = NULL;
 740
 741    return OK;
 742 }
 743
 744 static int
 745 store_gss_creds(request_rec *r, kerb_auth_config *conf, char *princ_name,
 746                 gss_cred_id_t delegated_cred)
 747 {
 748    OM_uint32 maj_stat, min_stat;
 749    krb5_principal princ = NULL;
 750    krb5_ccache ccache = NULL;
 751    krb5_error_code problem;
 752    krb5_context context;
 753    int ret = HTTP_INTERNAL_SERVER_ERROR;
 754
 755    problem = krb5_init_context(&context);
 756    if (problem) {
 757       log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "Cannot initialize krb5 context");
 758       return HTTP_INTERNAL_SERVER_ERROR;
 759    }
 760
 761    problem = krb5_parse_name(context, princ_name, &princ);
 762    if (problem) {
 763       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 764          "Cannot parse delegated username (%s)", krb5_get_err_text(context, problem));
 765       goto end;
 766    }
 767
 768    problem = create_krb5_ccache(context, r, conf, princ, &ccache);
 769    if (problem) {
 770       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 771          "Cannot create krb5 ccache (%s)", krb5_get_err_text(context, problem));
 772       goto end;
 773    }
 774
 775    maj_stat = gss_krb5_copy_ccache(&min_stat, delegated_cred, ccache);
 776    if (GSS_ERROR(maj_stat)) {
 777       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 778          "Cannot store delegated credential (%s)",
 779          get_gss_error(r->pool, min_stat, "gss_krb5_copy_ccache"));
 780       goto end;
 781    }
 782
 783    krb5_cc_close(context, ccache);
 784    ccache = NULL;
 785    ret = 0;
 786
 787 end:
 788    if (princ)
 789       krb5_free_principal(context, princ);
 790    if (ccache)
 791       krb5_cc_destroy(context, ccache);
 792    krb5_free_context(context);
 793    return ret;
 794 }
 795
 796 static int
 797 get_gss_creds(request_rec *r,
 798               kerb_auth_config *conf,
 799               gss_cred_id_t *server_creds)
 800 {
 801    gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
 802    OM_uint32 major_status, minor_status, minor_status2;
 803    gss_name_t server_name = GSS_C_NO_NAME;
 804    char buf[1024];
 805
 806    snprintf(buf, sizeof(buf), "%s/%s", "khttp", ap_get_server_name(r));
 807
 808    input_token.value = buf;
 809    input_token.length = strlen(buf) + 1;
 810
 811    major_status = gss_import_name(&minor_status, &input_token,
 812                                   GSS_C_NT_USER_NAME,
 813                                   &server_name);
 814    if (GSS_ERROR(major_status)) {
 815       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 816                  "%s", get_gss_error(r->pool, minor_status,
 817                  "gss_import_name() failed"));
 818       return HTTP_INTERNAL_SERVER_ERROR;
 819    }
 820
 821    major_status = gss_acquire_cred(&minor_status, server_name, GSS_C_INDEFINITE,
 822                                    GSS_C_NO_OID_SET, GSS_C_ACCEPT,
 823                                    server_creds, NULL, NULL);
 824    gss_release_name(&minor_status2, &server_name);
 825    if (GSS_ERROR(major_status)) {
 826       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 827                  "%s", get_gss_error(r->pool, minor_status,
 828                                      "gss_acquire_cred() failed"));
 829       return HTTP_INTERNAL_SERVER_ERROR;
 830    }
 831
 832    return 0;
 833 }
 834
 835 static int
 836 authenticate_user_gss(request_rec *r,
 837                       kerb_auth_config *conf,
 838                       const char *auth_line)
 839 {
 840   OM_uint32 major_status, minor_status, minor_status2;
 841   gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
 842   gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER;
 843   const char *auth_param = NULL;
 844   int ret;
 845   gss_name_t client_name = GSS_C_NO_NAME;
 846   gss_cred_id_t delegated_cred = GSS_C_NO_CREDENTIAL;
 847   static int initial_return = HTTP_UNAUTHORIZED;
 848
 849   /* needed to work around replay caches */
 850   if (!ap_is_initial_req(r))
 851      return initial_return;
 852   initial_return = HTTP_UNAUTHORIZED;
 853
 854   if (gss_connection == NULL) {
 855      gss_connection = ap_pcalloc(r->connection->pool, sizeof(*gss_connection));
 856      if (gss_connection == NULL) {
 857         log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 858                    "ap_pcalloc() failed (not enough memory)");
 859         ret = HTTP_INTERNAL_SERVER_ERROR;
 860         goto end;
 861      }
 862      memset(gss_connection, 0, sizeof(*gss_connection));
 863      ap_register_cleanup(r->connection->pool, gss_connection, cleanup_gss_connection, ap_null_cleanup);
 864   }
 865
 866   if (conf->krb_5_keytab)
 867      /* use really strcat(), since the string passed to putenv() will become
 868       * part of the enviroment and shouldn't be free()ed by apache */
 869      /* XXX space isn't allocated !!! */
 870      putenv(strcat("KRB5_KTNAME=", conf->krb_5_keytab));
 871
 872   if (gss_connection->server_creds == GSS_C_NO_CREDENTIAL) {
 873      ret = get_gss_creds(r, conf, &gss_connection->server_creds);
 874      if (ret)
 875         goto end;
 876   }
 877
 878   /* ap_getword() shifts parameter */
 879   auth_param = ap_getword_white(r->pool, &auth_line);
 880   if (auth_param == NULL) {
 881      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 882                 "No Authorization parameter in request from client");
 883      ret = HTTP_UNAUTHORIZED;
 884      goto end;
 885   }
 886
 887   input_token.length = ap_base64decode_len(auth_param) + 1;
 888   input_token.value = ap_pcalloc(r->connection->pool, input_token.length);
 889   if (input_token.value == NULL) {
 890      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 891                 "ap_pcalloc() failed (not enough memory)");
 892      ret = HTTP_INTERNAL_SERVER_ERROR;
 893      goto end;
 894   }
 895   input_token.length = ap_base64decode(input_token.value, auth_param);
 896
 897 #if 0
 898   major_status = gss_accept_sec_context(
 899 #else
 900   major_status = gss_accept_sec_context_spnego(
 901 #endif
 902                                         &minor_status,
 903                                         &gss_connection->context,
 904                                         gss_connection->server_creds,
 905                                         &input_token,
 906                                         GSS_C_NO_CHANNEL_BINDINGS,
 907                                         &client_name,
 908                                         NULL,
 909                                         &output_token,
 910                                         NULL,
 911                                         NULL,
 912                                         &delegated_cred);
 913   if (output_token.length) {
 914      char *token = NULL;
 915      size_t len;
 916
 917      len = ap_base64encode_len(output_token.length) + 1;
 918      token = ap_pcalloc(r->connection->pool, len + 1);
 919      if (token == NULL) {
 920         log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 921                    "ap_pcalloc() failed (not enough memory)");
 922         ret = HTTP_INTERNAL_SERVER_ERROR;
 923         gss_release_buffer(&minor_status2, &output_token);
 924         goto end;
 925      }
 926      ap_base64encode(token, output_token.value, output_token.length);
 927      token[len] = '\0';
 928      ap_table_set(r->err_headers_out, "WWW-Authenticate",
 929                   ap_pstrcat(r->pool, "Negotiate ", token, NULL));
 930      gss_release_buffer(&minor_status2, &output_token);
 931   }
 932
 933   if (GSS_ERROR(major_status)) {
 934      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 935                 "%s", get_gss_error(r->pool, minor_status,
 936                                     "gss_accept_sec_context() failed"));
 937      ret = HTTP_UNAUTHORIZED;
 938      goto end;
 939   }
 940
 941   if (major_status & GSS_S_CONTINUE_NEEDED) {
 942      /* Some GSSAPI mechanism (eg GSI from Globus) may require multiple
 943       * iterations to establish authentication */
 944      ret = HTTP_UNAUTHORIZED;
 945      goto end;
 946   }
 947
 948   major_status = gss_display_name(&minor_status, client_name, &output_token, NULL);
 949   gss_release_name(&minor_status, &client_name);
 950   if (GSS_ERROR(major_status)) {
 951     log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 952                "%s", get_gss_error(r->pool, minor_status,
 953                                    "gss_export_name() failed"));
 954     ret = HTTP_INTERNAL_SERVER_ERROR;
 955     goto end;
 956   }
 957
 958   MK_AUTH_TYPE = "Negotiate";
 959   MK_USER = ap_pstrdup(r->pool, output_token.value);
 960
 961   if (conf->krb_save_credentials && delegated_cred != GSS_C_NO_CREDENTIAL)
 962      store_gss_creds(r, conf, (char *)output_token.value, delegated_cred);
 963
 964   gss_release_buffer(&minor_status, &output_token);
 965
 966   ret = OK;
 967
 968 end:
 969   if (delegated_cred)
 970      gss_release_cred(&minor_status, &delegated_cred);
 971
 972   if (output_token.length)
 973      gss_release_buffer(&minor_status, &output_token);
 974
 975   if (client_name != GSS_C_NO_NAME)
 976      gss_release_name(&minor_status, &client_name);
 977
 978   cleanup_gss_connection(gss_connection);
 979
 980   initial_return = ret;
 981   return ret;
 982 }
 983 #endif /* KRB5 */
 984
 985
 986 static void
 987 note_kerb_auth_failure(request_rec *r, const kerb_auth_config *conf,
 988                        int use_krb4, int use_krb5)
 989 {
 990    const char *auth_name = NULL;
 991    int set_basic = 0;
 992
 993    /* get the user realm specified in .htaccess */
 994    auth_name = ap_auth_name(r);
 995
 996    /* XXX should the WWW-Authenticate header be cleared first? */
 997 #ifdef KRB5
 998    if (use_krb5 && conf->krb_method_gssapi)
 999       ap_table_add(r->err_headers_out, "WWW-Authenticate", "Negotiate ");
1000    if (use_krb5 && conf->krb_method_k5pass) {
1001       ap_table_add(r->err_headers_out, "WWW-Authenticate",
1002                    ap_pstrcat(r->pool, "Basic realm=\"", auth_name, "\"", NULL));
1003       set_basic = 1;
1004    }
1005 #endif
1006
1007 #ifdef KRB4
1008    if (use_krb4 && conf->krb_method_k4pass && !set_basic)
1009       ap_table_add(r->err_headers_out, "WWW-Authenticate",
1010                    ap_pstrcat(r->pool, "Basic realm=\"", auth_name, "\"", NULL));
1011 #endif
1012 }
1013
1014 int kerb_authenticate_user(request_rec *r)
1015 {
1016    kerb_auth_config *conf =
1017       (kerb_auth_config *) ap_get_module_config(r->per_dir_config,
1018                                                 &auth_kerb_module);
1019    const char *auth_type = NULL;
1020    const char *auth_line = NULL;
1021    const char *type = NULL;
1022    int use_krb5 = 0, use_krb4 = 0;
1023    int ret;
1024
1025    /* get the type specified in .htaccess */
1026    type = ap_auth_type(r);
1027
1028    if (type && strcasecmp(type, "Kerberos") == 0)
1029       use_krb5 = use_krb4 = 1;
1030    else if(type && strcasecmp(type, "KerberosV5") == 0)
1031       use_krb4 = 0;
1032    else if(type && strcasecmp(type, "KerberosV4") == 0)
1033       use_krb5 = 0;
1034    else
1035       return DECLINED;
1036
1037    /* get what the user sent us in the HTTP header */
1038    auth_line = MK_TABLE_GET(r->headers_in, "Authorization");
1039    if (!auth_line) {
1040       note_kerb_auth_failure(r, conf, use_krb4, use_krb5);
1041       return HTTP_UNAUTHORIZED;
1042    }
1043    auth_type = ap_getword_white(r->pool, &auth_line);
1044
1045    ret = HTTP_UNAUTHORIZED;
1046
1047 #ifdef KRB5
1048    if (use_krb5 && conf->krb_method_gssapi &&
1049        strcasecmp(auth_type, "Negotiate") == 0) {
1050       ret = authenticate_user_gss(r, conf, auth_line);
1051    } else if (use_krb5 && conf->krb_method_k5pass &&
1052               strcasecmp(auth_type, "Basic") == 0) {
1053        ret = authenticate_user_krb5pwd(r, conf, auth_line);
1054    }
1055 #endif
1056
1057 #ifdef KRB4
1058    if (ret == HTTP_UNAUTHORIZED && use_krb4 && conf->krb_method_k4pass &&
1059        strcasecmp(auth_type, "Basic") == 0)
1060       ret = authenticate_user_krb4pwd(r, conf, auth_line);
1061 #endif
1062
1063    if (ret == HTTP_UNAUTHORIZED)
1064       note_kerb_auth_failure(r, conf, use_krb4, use_krb5);
1065
1066    return ret;
1067 }
1068
1069
1070 /***************************************************************************
1071  Module Setup/Configuration
1072  ***************************************************************************/
1073 #ifdef APXS1
1074 module MODULE_VAR_EXPORT auth_kerb_module = {
1075         STANDARD_MODULE_STUFF,
1076         NULL,                           /*      module initializer            */
1077         kerb_dir_create_config,         /*      per-directory config creator  */
1078         NULL,                           /*      per-directory config merger   */
1079         NULL,                           /*      per-server    config creator  */
1080         NULL,                           /*      per-server    config merger   */
1081         kerb_auth_cmds,                 /*      command table                 */
1082         NULL,                           /* [ 9] content handlers              */
1083         NULL,                           /* [ 2] URI-to-filename translation   */
1084         kerb_authenticate_user,         /* [ 5] check/validate user_id        */
1085         NULL,                           /* [ 6] check user_id is valid *here* */
1086         NULL,                           /* [ 4] check access by host address  */
1087         NULL,                           /* [ 7] MIME type checker/setter      */
1088         NULL,                           /* [ 8] fixups                        */
1089         NULL,                           /* [10] logger                        */
1090         NULL,                           /* [ 3] header parser                 */
1091         NULL,                           /*      process initialization        */
1092         NULL,                           /*      process exit/cleanup          */
1093         NULL                            /* [ 1] post read_request handling    */
1094 };
1095 #else
1096 static int
1097 kerb_init_handler(apr_pool_t *p, apr_pool_t *plog,
1098                   apr_pool_t *ptemp, server_rec *s)
1099 {
1100    ap_add_version_component(p, "mod_auth_kerb/" MODAUTHKERB_VERSION);
1101    return OK;
1102 }
1103
1104 void kerb_register_hooks(apr_pool_t *p)
1105 {
1106    ap_hook_post_config(kerb_init_handler, NULL, NULL, APR_HOOK_MIDDLE);
1107    ap_hook_check_user_id(kerb_authenticate_user, NULL, NULL, APR_HOOK_MIDDLE);
1108 }
1109
1110 module AP_MODULE_DECLARE_DATA auth_kerb_module =
1111 {
1112    STANDARD20_MODULE_STUFF,
1113    kerb_dir_create_config,      /* create per-dir    conf structures  */
1114    NULL,                        /* merge  per-dir    conf structures  */
1115    NULL,                        /* create per-server conf structures  */
1116    NULL,                        /* merge  per-server conf structures  */
1117    kerb_auth_cmds,              /* table of configuration directives  */
1118    kerb_register_hooks          /* register hooks                     */
1119 };
1120 #endif