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_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 276                  "Cannot get krb4 ticket: krb_get_pw_in_tkt() failed: %s",
 277                  krb_get_err_text(ret));
 278       return ret;
 279    }
 280
 281    hostname = ap_get_server_name(r);
 282
 283    hp = gethostbyname(hostname);
 284    if (hp == NULL) {
 285       dest_tkt();
 286       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 287                  "Cannot verify krb4 ticket: gethostbyname() failed: %s",
 288                  hstrerror(h_errno));
 289       return h_errno;
 290    }
 291    memcpy(&addr, hp->h_addr, sizeof(addr));
 292
 293    phost = krb_get_phost((char *)hostname);
 294
 295    krb_get_lrealm(lrealm, 1);
 296
 297    ret = krb_mk_req(&ticket, linstance, phost, lrealm, 0);
 298    if (ret) {
 299       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 300                  "Cannot verify krb4 ticket: krb_mk_req() failed: %s",
 301                  krb_get_err_text(ret));
 302       dest_tkt();
 303       return ret;
 304    }
 305
 306    ret = krb_rd_req(&ticket, linstance, phost, addr, &authdata, srvtab);
 307    if (ret) {
 308       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 309                  "Cannot verify krb4 ticket: krb_rd_req() failed: %s",
 310                  krb_get_err_text(ret));
 311       dest_tkt();
 312    }
 313
 314    return ret;
 315 }
 316
 317 static int
 318 krb4_cache_cleanup(void *data)
 319 {
 320    char *tkt_file = (char *) data;
 321
 322    krb_set_tkt_string(tkt_file);
 323    dest_tkt();
 324    return OK;
 325 }
 326
 327 static int
 328 authenticate_user_krb4pwd(request_rec *r,
 329                           kerb_auth_config *conf,
 330                           const char *auth_line)
 331 {
 332    int ret;
 333    const char *sent_pw;
 334    const char *sent_name;
 335    char *sent_instance;
 336    char tkt_file[32];
 337    char *tkt_file_p = NULL;
 338    int fd;
 339    const char *realms;
 340    const char *realm;
 341    char *user;
 342    char lrealm[REALM_SZ];
 343
 344    sent_pw = ap_pbase64decode(r->pool, auth_line);
 345    sent_name = ap_getword (r->pool, &sent_pw, ':');
 346
 347    /* do not allow user to override realm setting of server */
 348    if (strchr(sent_name, '@')) {
 349       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 350                  "specifying realm in user name is prohibited");
 351       return HTTP_UNAUTHORIZED;
 352    }
 353
 354    sent_instance = strchr(sent_name, '.');
 355    if (sent_instance)
 356       *sent_instance++ = '\0';
 357
 358    snprintf(tkt_file, sizeof(tkt_file), "/tmp/apache_tkt_XXXXXX");
 359    fd = mkstemp(tkt_file);
 360    if (fd < 0) {
 361       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 362                  "Cannot create krb4 ccache: mkstemp() failed: %s",
 363                  strerror(errno));
 364       return HTTP_INTERNAL_SERVER_ERROR;
 365    }
 366
 367    tkt_file_p = ap_pstrdup(r->pool, tkt_file);
 368    ap_register_cleanup(r->pool, tkt_file_p,
 369                        krb4_cache_cleanup, ap_null_cleanup);
 370
 371    krb_set_tkt_string(tkt_file);
 372
 373    realms = conf->krb_auth_realms;
 374    do {
 375       memset(lrealm, 0, sizeof(lrealm));
 376       realm = NULL;
 377       if (realms)
 378          realm = ap_getword_white(r->pool, &realms);
 379
 380       if (realm == NULL) {
 381          ret = krb_get_lrealm(lrealm, 1);
 382          realm = lrealm;
 383       }
 384       if (realm == NULL || *realm == '\0')
 385          break;
 386
 387       ret = verify_krb4_user(r, (char *)sent_name,
 388                              (sent_instance) ? sent_instance : "",
 389                              (char *)realm, (char *)sent_pw, "khttp",
 390                              conf->krb_4_srvtab);
 391       if (ret == 0)
 392          break;
 393    } while (realms && *realms);
 394
 395    if (ret) {
 396       log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "Verifying krb4 password failed");
 397       ret = HTTP_UNAUTHORIZED;
 398       goto end;
 399    }
 400
 401    user = ap_pstrdup(r->pool, sent_name);
 402    if (sent_instance)
 403       user = ap_pstrcat(r->pool, user, ".", sent_instance, NULL);
 404    user = ap_pstrcat(r->pool, user, "@", realm, NULL);
 405
 406    MK_USER = user;
 407    MK_AUTH_TYPE = "Basic";
 408    ap_table_setn(r->subprocess_env, "KRBTKFILE", tkt_file_p);
 409
 410    if (!conf->krb_save_credentials)
 411       krb4_cache_cleanup(tkt_file);
 412
 413 end:
 414    if (ret)
 415       krb4_cache_cleanup(tkt_file);
 416    close(fd);
 417    tf_close();
 418
 419    return ret;
 420 }
 421 #endif /* KRB4 */
 422
 423 #ifdef KRB5
 424 /***************************************************************************
 425  Username/Password Validation for Krb5
 426  ***************************************************************************/
 427 /* Inspired by krb5_verify_user from Heimdal */
 428 static krb5_error_code
 429 verify_krb5_user(request_rec *r, krb5_context context, krb5_principal principal,
 430                  krb5_ccache ccache, const char *password, const char *service,
 431                  krb5_keytab keytab)
 432 {
 433    krb5_creds creds;
 434    krb5_principal server = NULL;
 435    krb5_error_code ret;
 436    krb5_verify_init_creds_opt opt;
 437
 438    memset(&creds, 0, sizeof(creds));
 439
 440    ret = krb5_get_init_creds_password(context, &creds, principal,
 441                                       (char *)password, krb5_prompter_posix,
 442                                       NULL, 0, NULL, NULL);
 443    if (ret)
 444       return ret;
 445
 446    ret = krb5_sname_to_principal(context, ap_get_server_name(r), service,
 447                                  KRB5_NT_SRV_HST, &server);
 448    if (ret)
 449       goto end;
 450
 451    krb5_verify_init_creds_opt_init(&opt);
 452    krb5_verify_init_creds_opt_set_ap_req_nofail(&opt, 1);
 453
 454    ret = krb5_verify_init_creds(context, &creds, server, keytab, NULL, &opt);
 455    if (ret)
 456       goto end;
 457
 458    if (ccache) {
 459       ret = krb5_cc_initialize(context, ccache, principal);
 460       if (ret == 0)
 461          ret = krb5_cc_store_cred(context, ccache, &creds);
 462    }
 463
 464 end:
 465    krb5_free_cred_contents(context, &creds);
 466    if (server)
 467       krb5_free_principal(context, server);
 468    return ret;
 469 }
 470
 471 static int
 472 krb5_cache_cleanup(void *data)
 473 {
 474    krb5_context context;
 475    krb5_ccache  cache;
 476    krb5_error_code problem;
 477    char *cache_name = (char *) data;
 478
 479    problem = krb5_init_context(&context);
 480    if (problem) {
 481       /* ap_log_error(APLOG_MARK, APLOG_ERR, 0, NULL, "krb5_init_context() failed"); */
 482       return HTTP_INTERNAL_SERVER_ERROR;
 483    }
 484
 485    problem = krb5_cc_resolve(context, cache_name, &cache);
 486    if (problem) {
 487       /* log_error(APLOG_MARK, APLOG_ERR, 0, NULL,
 488                 "krb5_cc_resolve() failed (%s: %s)",
 489                 cache_name, krb5_get_err_text(context, problem)); */
 490       return HTTP_INTERNAL_SERVER_ERROR;
 491    }
 492
 493    krb5_cc_destroy(context, cache);
 494    krb5_free_context(context);
 495    return OK;
 496 }
 497
 498 static int
 499 create_krb5_ccache(krb5_context kcontext,
 500                    request_rec *r,
 501                    kerb_auth_config *conf,
 502                    krb5_principal princ,
 503                    krb5_ccache *ccache)
 504 {
 505    char *ccname;
 506    krb5_error_code problem;
 507    int ret;
 508    krb5_ccache tmp_ccache = NULL;
 509
 510 #ifdef HEIMDAL
 511    problem = krb5_cc_gen_new(kcontext, &krb5_fcc_ops, &tmp_ccache);
 512 #else
 513    problem = krb5_fcc_generate_new(kcontext, &tmp_ccache);
 514    /* krb5_fcc_generate_new() doesn't set KRB5_TC_OPENCLOSE, which makes
 515       krb5_cc_initialize() fail */
 516    krb5_fcc_set_flags(kcontext, tmp_ccache, KRB5_TC_OPENCLOSE);
 517 #endif
 518    if (problem) {
 519       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 520                  "Cannot create file for new krb5 ccache: %s",
 521                  krb5_get_err_text(kcontext, problem));
 522       ret = HTTP_INTERNAL_SERVER_ERROR;
 523       goto end;
 524    }
 525
 526    ccname = ap_pstrdup(r->pool, krb5_cc_get_name(kcontext, tmp_ccache));
 527
 528    problem = krb5_cc_initialize(kcontext, tmp_ccache, princ);
 529    if (problem) {
 530       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 531                  "Cannot initialize krb5 ccache %s: krb5_cc_initialize() failed: %s",
 532                  ccname, krb5_get_err_text(kcontext, problem));
 533       ret = HTTP_INTERNAL_SERVER_ERROR;
 534       goto end;
 535    }
 536
 537    ap_table_setn(r->subprocess_env, "KRB5CCNAME", ccname);
 538    ap_register_cleanup(r->pool, ccname,
 539                        krb5_cache_cleanup, ap_null_cleanup);
 540
 541    *ccache = tmp_ccache;
 542    tmp_ccache = NULL;
 543
 544    ret = OK;
 545
 546 end:
 547    if (tmp_ccache)
 548       krb5_cc_destroy(kcontext, tmp_ccache);
 549
 550    return ret;
 551 }
 552
 553 static int
 554 store_krb5_creds(krb5_context kcontext,
 555                  request_rec *r,
 556                  kerb_auth_config *conf,
 557                  krb5_ccache delegated_cred)
 558 {
 559    char errstr[1024];
 560    krb5_error_code problem;
 561    krb5_principal princ;
 562    krb5_ccache ccache;
 563    int ret;
 564
 565    problem = krb5_cc_get_principal(kcontext, delegated_cred, &princ);
 566    if (problem) {
 567       snprintf(errstr, sizeof(errstr), "krb5_cc_get_principal() failed: %s",
 568                krb5_get_err_text(kcontext, problem));
 569       return HTTP_INTERNAL_SERVER_ERROR;
 570    }
 571
 572    ret = create_krb5_ccache(kcontext, r, conf, princ, &ccache);
 573    if (ret) {
 574       krb5_free_principal(kcontext, princ);
 575       return ret;
 576    }
 577
 578 #ifdef HEIMDAL
 579    problem = krb5_cc_copy_cache(kcontext, delegated_cred, ccache);
 580 #else
 581    problem = krb5_cc_copy_creds(kcontext, delegated_cred, ccache);
 582 #endif
 583    krb5_free_principal(kcontext, princ);
 584    if (problem) {
 585       snprintf(errstr, sizeof(errstr), "Failed to store credentials: %s",
 586                krb5_get_err_text(kcontext, problem));
 587       krb5_cc_destroy(kcontext, ccache);
 588       return HTTP_INTERNAL_SERVER_ERROR;
 589    }
 590
 591    krb5_cc_close(kcontext, ccache);
 592    return OK;
 593 }
 594
 595
 596 int authenticate_user_krb5pwd(request_rec *r,
 597                               kerb_auth_config *conf,
 598                               const char *auth_line)
 599 {
 600    const char      *sent_pw = NULL;
 601    const char      *sent_name = NULL;
 602    const char      *realms = NULL;
 603    krb5_context    kcontext = NULL;
 604    krb5_error_code code;
 605    krb5_principal  client = NULL;
 606    krb5_ccache     ccache = NULL;
 607    krb5_keytab     keytab = NULL;
 608    int             ret;
 609    char *name = NULL;
 610
 611    code = krb5_init_context(&kcontext);
 612    if (code) {
 613       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 614                  "Cannot initialize Kerberos5 context (%d)", code);
 615       return HTTP_INTERNAL_SERVER_ERROR;
 616    }
 617
 618    sent_pw = ap_pbase64decode(r->pool, auth_line);
 619    sent_name = ap_getword (r->pool, &sent_pw, ':');
 620    /* do not allow user to override realm setting of server */
 621    if (strchr(sent_name, '@')) {
 622       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 623                  "specifying realm in user name is prohibited");
 624       ret = HTTP_UNAUTHORIZED;
 625       goto end;
 626    }
 627
 628 #ifdef HEIMDAL
 629    code = krb5_cc_gen_new(kcontext, &krb5_mcc_ops, &ccache);
 630 #else
 631    code = krb5_mcc_generate_new(kcontext, &ccache);
 632 #endif
 633    if (code) {
 634       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 635                  "Cannot generate new ccache: %s",
 636                  krb5_get_err_text(kcontext, code));
 637       ret = HTTP_INTERNAL_SERVER_ERROR;
 638       goto end;
 639    }
 640
 641    if (conf->krb_5_keytab)
 642       krb5_kt_resolve(kcontext, conf->krb_5_keytab, &keytab);
 643
 644    realms = conf->krb_auth_realms;
 645    do {
 646       if (realms && (code = krb5_set_default_realm(kcontext,
 647                                            ap_getword_white(r->pool, &realms))))
 648          continue;
 649
 650       if (client) {
 651          krb5_free_principal(kcontext, client);
 652          client = NULL;
 653       }
 654       code = krb5_parse_name(kcontext, sent_name, &client);
 655       if (code)
 656          continue;
 657
 658       code = verify_krb5_user(r, kcontext, client, ccache, sent_pw, "khttp",
 659                               keytab);
 660       if (code == 0)
 661          break;
 662
 663       /* ap_getword_white() used above shifts the parameter, so it's not
 664          needed to touch the realms variable */
 665    } while (realms && *realms);
 666
 667    memset((char *)sent_pw, 0, strlen(sent_pw));
 668
 669    if (code) {
 670       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 671                  "Verifying krb5 password failed: %s",
 672                  krb5_get_err_text(kcontext, code));
 673       ret = HTTP_UNAUTHORIZED;
 674       goto end;
 675    }
 676
 677    code = krb5_unparse_name(kcontext, client, &name);
 678    if (code) {
 679       log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "krb5_unparse_name() failed: %s",
 680                  krb5_get_err_text(kcontext, code));
 681       ret = HTTP_UNAUTHORIZED;
 682       goto end;
 683    }
 684    MK_USER = ap_pstrdup (r->pool, name);
 685    MK_AUTH_TYPE = "Basic";
 686    free(name);
 687
 688    if (conf->krb_save_credentials)
 689       store_krb5_creds(kcontext, r, conf, ccache);
 690
 691    ret = OK;
 692
 693 end:
 694    if (client)
 695       krb5_free_principal(kcontext, client);
 696    if (ccache)
 697       krb5_cc_destroy(kcontext, ccache);
 698    if (keytab)
 699       krb5_kt_close(kcontext, keytab);
 700    krb5_free_context(kcontext);
 701
 702    return ret;
 703 }
 704
 705 /*********************************************************************
 706  * GSSAPI Authentication
 707  ********************************************************************/
 708
 709 static const char *
 710 get_gss_error(MK_POOL *p, OM_uint32 error_status, char *prefix)
 711 {
 712    OM_uint32 maj_stat, min_stat;
 713    OM_uint32 msg_ctx = 0;
 714    gss_buffer_desc status_string;
 715    char buf[1024];
 716    size_t len;
 717
 718    snprintf(buf, sizeof(buf), "%s", prefix);
 719    len = strlen(buf);
 720    do {
 721       maj_stat = gss_display_status (&min_stat,
 722                                      error_status,
 723                                      GSS_C_MECH_CODE,
 724                                      GSS_C_NO_OID,
 725                                      &msg_ctx,
 726                                      &status_string);
 727       if (sizeof(buf) > len + status_string.length + 1) {
 728          sprintf(buf+len, ": %s", (char*) status_string.value);
 729          len += status_string.length;
 730       }
 731       gss_release_buffer(&min_stat, &status_string);
 732    } while (!GSS_ERROR(maj_stat) && msg_ctx != 0);
 733
 734    return (ap_pstrdup(p, buf));
 735 }
 736
 737 static int
 738 cleanup_gss_connection(void *data)
 739 {
 740    OM_uint32 minor_status;
 741    gss_connection_t *gss_conn = (gss_connection_t *)data;
 742
 743    if (data == NULL)
 744       return OK;
 745    if (gss_conn->context != GSS_C_NO_CONTEXT)
 746       gss_delete_sec_context(&minor_status, &gss_conn->context,
 747                              GSS_C_NO_BUFFER);
 748    if (gss_conn->server_creds != GSS_C_NO_CREDENTIAL)
 749       gss_release_cred(&minor_status, &gss_conn->server_creds);
 750
 751    gss_connection = NULL;
 752
 753    return OK;
 754 }
 755
 756 static int
 757 store_gss_creds(request_rec *r, kerb_auth_config *conf, char *princ_name,
 758                 gss_cred_id_t delegated_cred)
 759 {
 760    OM_uint32 maj_stat, min_stat;
 761    krb5_principal princ = NULL;
 762    krb5_ccache ccache = NULL;
 763    krb5_error_code problem;
 764    krb5_context context;
 765    int ret = HTTP_INTERNAL_SERVER_ERROR;
 766
 767    problem = krb5_init_context(&context);
 768    if (problem) {
 769       log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "Cannot initialize krb5 context");
 770       return HTTP_INTERNAL_SERVER_ERROR;
 771    }
 772
 773    problem = krb5_parse_name(context, princ_name, &princ);
 774    if (problem) {
 775       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 776          "Cannot parse delegated username (%s)", krb5_get_err_text(context, problem));
 777       goto end;
 778    }
 779
 780    problem = create_krb5_ccache(context, r, conf, princ, &ccache);
 781    if (problem) {
 782       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 783          "Cannot create krb5 ccache (%s)", krb5_get_err_text(context, problem));
 784       goto end;
 785    }
 786
 787    maj_stat = gss_krb5_copy_ccache(&min_stat, delegated_cred, ccache);
 788    if (GSS_ERROR(maj_stat)) {
 789       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 790          "Cannot store delegated credential (%s)",
 791          get_gss_error(r->pool, min_stat, "gss_krb5_copy_ccache"));
 792       goto end;
 793    }
 794
 795    krb5_cc_close(context, ccache);
 796    ccache = NULL;
 797    ret = 0;
 798
 799 end:
 800    if (princ)
 801       krb5_free_principal(context, princ);
 802    if (ccache)
 803       krb5_cc_destroy(context, ccache);
 804    krb5_free_context(context);
 805    return ret;
 806 }
 807
 808 static int
 809 get_gss_creds(request_rec *r,
 810               kerb_auth_config *conf,
 811               gss_cred_id_t *server_creds)
 812 {
 813    gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
 814    OM_uint32 major_status, minor_status, minor_status2;
 815    gss_name_t server_name = GSS_C_NO_NAME;
 816    char buf[1024];
 817
 818    snprintf(buf, sizeof(buf), "%s/%s", "khttp", ap_get_server_name(r));
 819
 820    input_token.value = buf;
 821    input_token.length = strlen(buf) + 1;
 822
 823    major_status = gss_import_name(&minor_status, &input_token,
 824                                   GSS_C_NT_USER_NAME,
 825                                   &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_import_name() failed"));
 830       return HTTP_INTERNAL_SERVER_ERROR;
 831    }
 832
 833    major_status = gss_acquire_cred(&minor_status, server_name, GSS_C_INDEFINITE,
 834                                    GSS_C_NO_OID_SET, GSS_C_ACCEPT,
 835                                    server_creds, NULL, NULL);
 836    gss_release_name(&minor_status2, &server_name);
 837    if (GSS_ERROR(major_status)) {
 838       log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 839                  "%s", get_gss_error(r->pool, minor_status,
 840                                      "gss_acquire_cred() failed"));
 841       return HTTP_INTERNAL_SERVER_ERROR;
 842    }
 843
 844    return 0;
 845 }
 846
 847 static int
 848 authenticate_user_gss(request_rec *r,
 849                       kerb_auth_config *conf,
 850                       const char *auth_line)
 851 {
 852   OM_uint32 major_status, minor_status, minor_status2;
 853   gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
 854   gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER;
 855   const char *auth_param = NULL;
 856   int ret;
 857   gss_name_t client_name = GSS_C_NO_NAME;
 858   gss_cred_id_t delegated_cred = GSS_C_NO_CREDENTIAL;
 859   static int initial_return = HTTP_UNAUTHORIZED;
 860
 861   /* needed to work around replay caches */
 862   if (!ap_is_initial_req(r))
 863      return initial_return;
 864   initial_return = HTTP_UNAUTHORIZED;
 865
 866   if (gss_connection == NULL) {
 867      gss_connection = ap_pcalloc(r->connection->pool, sizeof(*gss_connection));
 868      if (gss_connection == NULL) {
 869         log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 870                    "ap_pcalloc() failed (not enough memory)");
 871         ret = HTTP_INTERNAL_SERVER_ERROR;
 872         goto end;
 873      }
 874      memset(gss_connection, 0, sizeof(*gss_connection));
 875      ap_register_cleanup(r->connection->pool, gss_connection, cleanup_gss_connection, ap_null_cleanup);
 876   }
 877
 878   if (conf->krb_5_keytab)
 879      /* use really strcat(), since the string passed to putenv() will become
 880       * part of the enviroment and shouldn't be free()ed by apache */
 881      /* XXX space isn't allocated !!! */
 882      putenv(strcat("KRB5_KTNAME=", conf->krb_5_keytab));
 883
 884   if (gss_connection->server_creds == GSS_C_NO_CREDENTIAL) {
 885      ret = get_gss_creds(r, conf, &gss_connection->server_creds);
 886      if (ret)
 887         goto end;
 888   }
 889
 890   /* ap_getword() shifts parameter */
 891   auth_param = ap_getword_white(r->pool, &auth_line);
 892   if (auth_param == NULL) {
 893      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 894                 "No Authorization parameter in request from client");
 895      ret = HTTP_UNAUTHORIZED;
 896      goto end;
 897   }
 898
 899   input_token.length = ap_base64decode_len(auth_param) + 1;
 900   input_token.value = ap_pcalloc(r->connection->pool, input_token.length);
 901   if (input_token.value == NULL) {
 902      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 903                 "ap_pcalloc() failed (not enough memory)");
 904      ret = HTTP_INTERNAL_SERVER_ERROR;
 905      goto end;
 906   }
 907   input_token.length = ap_base64decode(input_token.value, auth_param);
 908
 909 #if 0
 910   major_status = gss_accept_sec_context(
 911 #else
 912   major_status = gss_accept_sec_context_spnego(
 913 #endif
 914                                         &minor_status,
 915                                         &gss_connection->context,
 916                                         gss_connection->server_creds,
 917                                         &input_token,
 918                                         GSS_C_NO_CHANNEL_BINDINGS,
 919                                         &client_name,
 920                                         NULL,
 921                                         &output_token,
 922                                         NULL,
 923                                         NULL,
 924                                         &delegated_cred);
 925   if (output_token.length) {
 926      char *token = NULL;
 927      size_t len;
 928
 929      len = ap_base64encode_len(output_token.length) + 1;
 930      token = ap_pcalloc(r->connection->pool, len + 1);
 931      if (token == NULL) {
 932         log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 933                    "ap_pcalloc() failed (not enough memory)");
 934         ret = HTTP_INTERNAL_SERVER_ERROR;
 935         gss_release_buffer(&minor_status2, &output_token);
 936         goto end;
 937      }
 938      ap_base64encode(token, output_token.value, output_token.length);
 939      token[len] = '\0';
 940      ap_table_set(r->err_headers_out, "WWW-Authenticate",
 941                   ap_pstrcat(r->pool, "Negotiate ", token, NULL));
 942      gss_release_buffer(&minor_status2, &output_token);
 943   }
 944
 945   if (GSS_ERROR(major_status)) {
 946      log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 947                 "%s", get_gss_error(r->pool, minor_status,
 948                                     "gss_accept_sec_context() failed"));
 949      ret = HTTP_UNAUTHORIZED;
 950      goto end;
 951   }
 952
 953   if (major_status & GSS_S_CONTINUE_NEEDED) {
 954      /* Some GSSAPI mechanism (eg GSI from Globus) may require multiple
 955       * iterations to establish authentication */
 956      ret = HTTP_UNAUTHORIZED;
 957      goto end;
 958   }
 959
 960   major_status = gss_display_name(&minor_status, client_name, &output_token, NULL);
 961   gss_release_name(&minor_status, &client_name);
 962   if (GSS_ERROR(major_status)) {
 963     log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 964                "%s", get_gss_error(r->pool, minor_status,
 965                                    "gss_export_name() failed"));
 966     ret = HTTP_INTERNAL_SERVER_ERROR;
 967     goto end;
 968   }
 969
 970   MK_AUTH_TYPE = "Negotiate";
 971   MK_USER = ap_pstrdup(r->pool, output_token.value);
 972
 973   if (conf->krb_save_credentials && delegated_cred != GSS_C_NO_CREDENTIAL)
 974      store_gss_creds(r, conf, (char *)output_token.value, delegated_cred);
 975
 976   gss_release_buffer(&minor_status, &output_token);
 977
 978   ret = OK;
 979
 980 end:
 981   if (delegated_cred)
 982      gss_release_cred(&minor_status, &delegated_cred);
 983
 984   if (output_token.length)
 985      gss_release_buffer(&minor_status, &output_token);
 986
 987   if (client_name != GSS_C_NO_NAME)
 988      gss_release_name(&minor_status, &client_name);
 989
 990   cleanup_gss_connection(gss_connection);
 991
 992   initial_return = ret;
 993   return ret;
 994 }
 995 #endif /* KRB5 */
 996
 997
 998 static void
 999 note_kerb_auth_failure(request_rec *r, const kerb_auth_config *conf,
1000                        int use_krb4, int use_krb5)
1001 {
1002    const char *auth_name = NULL;
1003    int set_basic = 0;
1004
1005    /* get the user realm specified in .htaccess */
1006    auth_name = ap_auth_name(r);
1007
1008    /* XXX should the WWW-Authenticate header be cleared first? */
1009 #ifdef KRB5
1010    if (use_krb5 && conf->krb_method_gssapi)
1011       ap_table_add(r->err_headers_out, "WWW-Authenticate", "Negotiate ");
1012    if (use_krb5 && conf->krb_method_k5pass) {
1013       ap_table_add(r->err_headers_out, "WWW-Authenticate",
1014                    ap_pstrcat(r->pool, "Basic realm=\"", auth_name, "\"", NULL));
1015       set_basic = 1;
1016    }
1017 #endif
1018
1019 #ifdef KRB4
1020    if (use_krb4 && conf->krb_method_k4pass && !set_basic)
1021       ap_table_add(r->err_headers_out, "WWW-Authenticate",
1022                    ap_pstrcat(r->pool, "Basic realm=\"", auth_name, "\"", NULL));
1023 #endif
1024 }
1025
1026 int kerb_authenticate_user(request_rec *r)
1027 {
1028    kerb_auth_config *conf =
1029       (kerb_auth_config *) ap_get_module_config(r->per_dir_config,
1030                                                 &auth_kerb_module);
1031    const char *auth_type = NULL;
1032    const char *auth_line = NULL;
1033    const char *type = NULL;
1034    int use_krb5 = 0, use_krb4 = 0;
1035    int ret;
1036
1037    /* get the type specified in .htaccess */
1038    type = ap_auth_type(r);
1039
1040    if (type && strcasecmp(type, "Kerberos") == 0)
1041       use_krb5 = use_krb4 = 1;
1042    else if(type && strcasecmp(type, "KerberosV5") == 0)
1043       use_krb4 = 0;
1044    else if(type && strcasecmp(type, "KerberosV4") == 0)
1045       use_krb5 = 0;
1046    else
1047       return DECLINED;
1048
1049    /* get what the user sent us in the HTTP header */
1050    auth_line = MK_TABLE_GET(r->headers_in, "Authorization");
1051    if (!auth_line) {
1052       note_kerb_auth_failure(r, conf, use_krb4, use_krb5);
1053       return HTTP_UNAUTHORIZED;
1054    }
1055    auth_type = ap_getword_white(r->pool, &auth_line);
1056
1057    ret = HTTP_UNAUTHORIZED;
1058
1059 #ifdef KRB5
1060    if (use_krb5 && conf->krb_method_gssapi &&
1061        strcasecmp(auth_type, "Negotiate") == 0) {
1062       ret = authenticate_user_gss(r, conf, auth_line);
1063    } else if (use_krb5 && conf->krb_method_k5pass &&
1064               strcasecmp(auth_type, "Basic") == 0) {
1065        ret = authenticate_user_krb5pwd(r, conf, auth_line);
1066    }
1067 #endif
1068
1069 #ifdef KRB4
1070    if (ret == HTTP_UNAUTHORIZED && use_krb4 && conf->krb_method_k4pass &&
1071        strcasecmp(auth_type, "Basic") == 0)
1072       ret = authenticate_user_krb4pwd(r, conf, auth_line);
1073 #endif
1074
1075    if (ret == HTTP_UNAUTHORIZED)
1076       note_kerb_auth_failure(r, conf, use_krb4, use_krb5);
1077
1078    return ret;
1079 }
1080
1081
1082 /***************************************************************************
1083  Module Setup/Configuration
1084  ***************************************************************************/
1085 #ifdef APXS1
1086 module MODULE_VAR_EXPORT auth_kerb_module = {
1087         STANDARD_MODULE_STUFF,
1088         NULL,                           /*      module initializer            */
1089         kerb_dir_create_config,         /*      per-directory config creator  */
1090         NULL,                           /*      per-directory config merger   */
1091         NULL,                           /*      per-server    config creator  */
1092         NULL,                           /*      per-server    config merger   */
1093         kerb_auth_cmds,                 /*      command table                 */
1094         NULL,                           /* [ 9] content handlers              */
1095         NULL,                           /* [ 2] URI-to-filename translation   */
1096         kerb_authenticate_user,         /* [ 5] check/validate user_id        */
1097         NULL,                           /* [ 6] check user_id is valid *here* */
1098         NULL,                           /* [ 4] check access by host address  */
1099         NULL,                           /* [ 7] MIME type checker/setter      */
1100         NULL,                           /* [ 8] fixups                        */
1101         NULL,                           /* [10] logger                        */
1102         NULL,                           /* [ 3] header parser                 */
1103         NULL,                           /*      process initialization        */
1104         NULL,                           /*      process exit/cleanup          */
1105         NULL                            /* [ 1] post read_request handling    */
1106 };
1107 #else
1108 static int
1109 kerb_init_handler(apr_pool_t *p, apr_pool_t *plog,
1110                   apr_pool_t *ptemp, server_rec *s)
1111 {
1112    ap_add_version_component(p, "mod_auth_kerb/" MODAUTHKERB_VERSION);
1113    return OK;
1114 }
1115
1116 void kerb_register_hooks(apr_pool_t *p)
1117 {
1118    ap_hook_post_config(kerb_init_handler, NULL, NULL, APR_HOOK_MIDDLE);
1119    ap_hook_check_user_id(kerb_authenticate_user, NULL, NULL, APR_HOOK_MIDDLE);
1120 }
1121
1122 module AP_MODULE_DECLARE_DATA auth_kerb_module =
1123 {
1124    STANDARD20_MODULE_STUFF,
1125    kerb_dir_create_config,      /* create per-dir    conf structures  */
1126    NULL,                        /* merge  per-dir    conf structures  */
1127    NULL,                        /* create per-server conf structures  */
1128    NULL,                        /* merge  per-server conf structures  */
1129    kerb_auth_cmds,              /* table of configuration directives  */
1130    kerb_register_hooks          /* register hooks                     */
1131 };
1132 #endif