cups/auth.c

   1 /*
   2  * "$Id: auth.c 6397 2007-03-25 23:33:32Z mike $"
   3  *
   4  *   Authentication functions for the Common UNIX Printing System (CUPS).
   5  *
   6  *   Copyright 1997-2007 by Easy Software Products.
   7  *
   8  *   This file contains Kerberos support code, copyright 2006 by
   9  *   Jelmer Vernooij.
  10  *
  11  *   These coded instructions, statements, and computer programs are the
  12  *   property of Easy Software Products and are protected by Federal
  13  *   copyright law.  Distribution and use rights are outlined in the file
  14  *   "LICENSE.txt" which should have been included with this file.  If this
  15  *   file is missing or damaged please contact Easy Software Products
  16  *   at:
  17  *
  18  *       Attn: CUPS Licensing Information
  19  *       Easy Software Products
  20  *       44141 Airport View Drive, Suite 204
  21  *       Hollywood, Maryland 20636 USA
  22  *
  23  *       Voice: (301) 373-9600
  24  *       EMail: cups-info@cups.org
  25  *         WWW: http://www.cups.org
  26  *
  27  *   This file is subject to the Apple OS-Developed Software exception.
  28  *
  29  * Contents:
  30  *
  31  *   cupsDoAuthentication() - Authenticate a request.
  32  *   DEBUG_gss_printf()     - Show debug error messages from GSSAPI...
  33  *   cups_get_gss_creds()   - Get CUPS service credentials for authentication.
  34  *   cups_local_auth()      - Get the local authorization certificate if
  35  *                            available/applicable...
  36  */
  37
  38 /*
  39  * Include necessary headers...
  40  */
  41
  42 #include "globals.h"
  43 #include "debug.h"
  44 #include <stdlib.h>
  45 #include <ctype.h>
  46 #include <errno.h>
  47 #include <fcntl.h>
  48 #include <sys/stat.h>
  49 #if defined(WIN32) || defined(__EMX__)
  50 #  include <io.h>
  51 #else
  52 #  include <unistd.h>
  53 #endif /* WIN32 || __EMX__ */
  54
  55 #if HAVE_AUTHORIZATION_H
  56 #  include <Security/Authorization.h>
  57 #  ifdef HAVE_SECBASEPRIV_H
  58 #    include <Security/SecBasePriv.h>
  59 #  else
  60 extern const char *cssmErrorString(int error);
  61 #  endif /* HAVE_SECBASEPRIV_H */
  62 #endif /* HAVE_AUTHORIZATION_H */
  63
  64
  65 /*
  66  * Local functions...
  67  */
  68
  69 #ifdef HAVE_GSSAPI
  70 #  ifdef DEBUG
  71 static void     DEBUG_gss_printf(OM_uint32 major_status, OM_uint32 minor_status,
  72                                  const char *message);
  73 #  endif /* DEBUG  */
  74 static gss_name_t cups_get_gss_creds(http_t *http, const char *service_name);
  75 #endif /* HAVE_GSSAPI */
  76 static int      cups_local_auth(http_t *http);
  77
  78
  79 /*
  80  * 'cupsDoAuthentication()' - Authenticate a request.
  81  *
  82  * This function should be called in response to a HTTP_UNAUTHORIZED
  83  * status, prior to resubmitting your request.
  84  *
  85  * @since CUPS 1.1.20@
  86  */
  87
  88 int                                     /* O - 0 on success, -1 on error */
  89 cupsDoAuthentication(http_t     *http,  /* I - HTTP connection to server */
  90                      const char *method,/* I - Request method (GET, POST, PUT) */
  91                      const char *resource)
  92                                         /* I - Resource path */
  93 {
  94   const char    *password;              /* Password string */
  95   char          prompt[1024],           /* Prompt for user */
  96                 realm[HTTP_MAX_VALUE],  /* realm="xyz" string */
  97                 nonce[HTTP_MAX_VALUE],  /* nonce="xyz" string */
  98                 encode[2048];           /* Encoded username:password */
  99   int           localauth;              /* Local authentication result */
 100   _cups_globals_t *cg;                  /* Global data */
 101
 102
 103   DEBUG_printf(("cupsDoAuthentication(http=%p, method=\"%s\", resource=\"%s\")\n",
 104                 http, method, resource));
 105   DEBUG_printf(("cupsDoAuthentication: digest_tries=%d, userpass=\"%s\"\n",
 106                 http->digest_tries, http->userpass));
 107   DEBUG_printf(("cupsDoAuthentication: WWW-Authenticate=\"%s\"\n",
 108                 httpGetField(http, HTTP_FIELD_WWW_AUTHENTICATE)));
 109
 110  /*
 111   * Clear the current authentication string...
 112   */
 113
 114   http->_authstring[0] = '\0';
 115
 116   if (http->authstring && http->authstring != http->_authstring)
 117     free(http->authstring);
 118
 119   http->authstring = http->_authstring;
 120
 121  /*
 122   * See if we can do local authentication...
 123   */
 124
 125   if (http->digest_tries < 3)
 126   {
 127     if ((localauth = cups_local_auth(http)) == 0)
 128     {
 129       DEBUG_printf(("cupsDoAuthentication: authstring=\"%s\"\n",
 130                     http->authstring));
 131
 132       if (http->status == HTTP_UNAUTHORIZED)
 133         http->digest_tries ++;
 134
 135       return (0);
 136     }
 137     else if (localauth == -1)
 138       return (-1);                      /* Error or canceled */
 139   }
 140
 141  /*
 142   * Nope, see if we should retry the current username:password...
 143   */
 144
 145   if ((http->digest_tries > 1 || !http->userpass[0]) &&
 146       strncmp(http->fields[HTTP_FIELD_WWW_AUTHENTICATE], "Negotiate", 9))
 147   {
 148    /*
 149     * Nope - get a new password from the user...
 150     */
 151
 152     cg = _cupsGlobals();
 153
 154     if (!cg->lang_default)
 155       cg->lang_default = cupsLangDefault();
 156
 157     snprintf(prompt, sizeof(prompt),
 158              _cupsLangString(cg->lang_default, _("Password for %s on %s? ")),
 159              cupsUser(),
 160              http->hostname[0] == '/' ? "localhost" : http->hostname);
 161
 162     http->digest_tries  = strncasecmp(http->fields[HTTP_FIELD_WWW_AUTHENTICATE],
 163                                       "Digest", 5) != 0;
 164     http->userpass[0]   = '\0';
 165
 166     if ((password = cupsGetPassword(prompt)) == NULL)
 167       return (-1);
 168
 169     if (!password[0])
 170       return (-1);
 171
 172     snprintf(http->userpass, sizeof(http->userpass), "%s:%s", cupsUser(),
 173              password);
 174   }
 175   else if (http->status == HTTP_UNAUTHORIZED)
 176     http->digest_tries ++;
 177
 178  /*
 179   * Got a password; encode it for the server...
 180   */
 181
 182   if (!strncmp(http->fields[HTTP_FIELD_WWW_AUTHENTICATE], "Negotiate", 9))
 183   {
 184 #ifdef HAVE_GSSAPI
 185    /*
 186     * Kerberos authentication...
 187     */
 188
 189     OM_uint32           minor_status,   /* Minor status code */
 190                         major_status;   /* Major status code */
 191     gss_buffer_desc     output_token = GSS_C_EMPTY_BUFFER,
 192                                         /* Output token */
 193                         input_token = GSS_C_EMPTY_BUFFER;
 194                                         /* Input token */
 195     char                *gss_service_name;
 196                                         /* GSS service name */
 197     const char          *authorization;
 198                                         /* Pointer into Authorization string */
 199
 200
 201 #  ifdef __APPLE__
 202    /*
 203     * If the weak-linked GSSAPI/Kerberos library is not present, don't try
 204     * to use it...
 205     */
 206
 207     if (gss_init_sec_context == NULL)
 208     {
 209       DEBUG_puts("cupsDoAuthentication: Weak-linked GSSAPI/Kerberos framework "
 210                  "is not present");
 211       return (-1);
 212     }
 213 #  endif /* __APPLE__ */
 214
 215     if (http->gssname == GSS_C_NO_NAME)
 216     {
 217       if ((gss_service_name = getenv("CUPS_GSSSERVICENAME")) == NULL)
 218         gss_service_name = CUPS_DEFAULT_GSSSERVICENAME;
 219       else
 220         DEBUG_puts("cupsDoAuthentication: GSS service name set via environment");
 221
 222       http->gssname = cups_get_gss_creds(http, gss_service_name);
 223     }
 224
 225    /*
 226     * Find the start of the Kerberos input token...
 227     */
 228
 229     authorization = httpGetField(http, HTTP_FIELD_WWW_AUTHENTICATE);
 230
 231     authorization += 9;
 232     while (*authorization && isspace(*authorization & 255))
 233       authorization ++;
 234
 235     if (*authorization)
 236     {
 237      /*
 238       * For SPNEGO, this is where we'll feed the server's authorization data
 239       * back into gss via input_token...
 240       */
 241     }
 242     else
 243     {
 244       if (http->gssctx != GSS_C_NO_CONTEXT)
 245       {
 246         major_status = gss_delete_sec_context(&minor_status, &http->gssctx,
 247                                               GSS_C_NO_BUFFER);
 248         http->gssctx = GSS_C_NO_CONTEXT;
 249       }
 250     }
 251
 252     major_status  = gss_init_sec_context(&minor_status, GSS_C_NO_CREDENTIAL,
 253                                          &http->gssctx,
 254                                          http->gssname, http->gssmech,
 255                                          GSS_C_MUTUAL_FLAG, GSS_C_INDEFINITE,
 256                                          GSS_C_NO_CHANNEL_BINDINGS,
 257                                          &input_token, &http->gssmech,
 258                                          &output_token, NULL, NULL);
 259
 260     if (input_token.value)
 261       free(input_token.value);
 262
 263     if (GSS_ERROR(major_status))
 264     {
 265 #  ifdef DEBUG
 266       DEBUG_gss_printf(major_status, minor_status,
 267                        "Unable to initialise security context");
 268 #  endif /* DEBUG */
 269       return (-1);
 270     }
 271
 272 #  ifdef DEBUG
 273     if (major_status == GSS_S_CONTINUE_NEEDED)
 274       DEBUG_gss_printf(major_status, minor_status, "Continuation needed!");
 275 #  endif /* DEBUG */
 276
 277     if (output_token.length)
 278     {
 279       httpEncode64_2(encode, sizeof(encode), output_token.value,
 280                      output_token.length);
 281
 282       http->authstring = malloc(strlen(encode) + 11);
 283       sprintf(http->authstring, "Negotiate %s", encode); /* Safe because allocated */
 284
 285       major_status = gss_release_buffer(&minor_status, &output_token);
 286     }
 287
 288    /*
 289     * Copy back what we can to _authstring for backwards compatibility...
 290     */
 291
 292     strlcpy(http->_authstring, http->authstring, sizeof(http->_authstring));
 293 #endif /* HAVE_GSSAPI */
 294   }
 295   else if (strncmp(http->fields[HTTP_FIELD_WWW_AUTHENTICATE], "Digest", 6))
 296   {
 297    /*
 298     * Basic authentication...
 299     */
 300
 301     httpEncode64_2(encode, sizeof(encode), http->userpass,
 302                    (int)strlen(http->userpass));
 303     snprintf(http->_authstring, sizeof(http->_authstring), "Basic %s", encode);
 304   }
 305   else
 306   {
 307    /*
 308     * Digest authentication...
 309     */
 310
 311     httpGetSubField(http, HTTP_FIELD_WWW_AUTHENTICATE, "realm", realm);
 312     httpGetSubField(http, HTTP_FIELD_WWW_AUTHENTICATE, "nonce", nonce);
 313
 314     httpMD5(cupsUser(), realm, strchr(http->userpass, ':') + 1, encode);
 315     httpMD5Final(nonce, method, resource, encode);
 316     snprintf(http->_authstring, sizeof(http->_authstring),
 317              "Digest username=\"%s\", realm=\"%s\", nonce=\"%s\", "
 318              "uri=\"%s\", response=\"%s\"", cupsUser(), realm, nonce,
 319              resource, encode);
 320   }
 321
 322   DEBUG_printf(("cupsDoAuthentication: authstring=\"%s\"\n", http->authstring));
 323
 324   return (0);
 325 }
 326
 327
 328 #ifdef HAVE_GSSAPI
 329 #  ifdef DEBUG
 330 /*
 331  * 'DEBUG_gss_printf()' - Show debug error messages from GSSAPI...
 332  */
 333
 334 static void
 335 DEBUG_gss_printf(OM_uint32 major_status,/* I - Major status code */
 336                  OM_uint32 minor_status,/* I - Minor status code */
 337                  const char *message)   /* I - Prefix for error message */
 338 {
 339   OM_uint32     err_major_status,       /* Major status code for display */
 340                 err_minor_status;       /* Minor status code for display */
 341   OM_uint32     msg_ctx;                /* Message context */
 342   gss_buffer_desc major_status_string = GSS_C_EMPTY_BUFFER,
 343                                         /* Major status message */
 344                 minor_status_string = GSS_C_EMPTY_BUFFER;
 345                                         /* Minor status message */
 346
 347
 348   msg_ctx          = 0;
 349   err_major_status = gss_display_status(&err_minor_status,
 350                                         major_status,
 351                                         GSS_C_GSS_CODE,
 352                                         GSS_C_NO_OID,
 353                                         &msg_ctx,
 354                                         &major_status_string);
 355
 356   if (!GSS_ERROR(err_major_status))
 357     err_major_status = gss_display_status(&err_minor_status,
 358                                           minor_status,
 359                                           GSS_C_MECH_CODE,
 360                                           GSS_C_NULL_OID,
 361                                           &msg_ctx,
 362                                           &minor_status_string);
 363
 364   printf("%s: %s, %s\n", message, (char *)major_status_string.value,
 365          (char *)minor_status_string.value);
 366
 367   gss_release_buffer(&err_minor_status, &major_status_string);
 368   gss_release_buffer(&err_minor_status, &minor_status_string);
 369 }
 370 #  endif /* DEBUG */
 371
 372
 373 /*
 374  * 'cups_get_gss_creds()' - Get CUPS service credentials for authentication.
 375  */
 376
 377 static gss_name_t                       /* O - Server name */
 378 cups_get_gss_creds(
 379     http_t     *http,                   /* I - Connection to server */
 380     const char *service_name)           /* I - Service name */
 381 {
 382   gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
 383                                         /* Service token */
 384   OM_uint32     major_status,           /* Major status code */
 385                 minor_status;           /* Minor status code */
 386   gss_name_t    server_name;            /* Server name */
 387   char          buf[1024],              /* Name buffer */
 388                 fqdn[HTTP_MAX_URI];     /* Server name buffer */
 389
 390
 391  /*
 392   * Get a server name we can use for authentication purposes...
 393   */
 394
 395   snprintf(buf, sizeof(buf), "%s@%s", service_name,
 396            httpGetHostname(http, fqdn, sizeof(fqdn)));
 397
 398   token.value  = buf;
 399   token.length = strlen(buf);
 400   server_name  = GSS_C_NO_NAME;
 401   major_status = gss_import_name(&minor_status, &token,
 402                                  GSS_C_NT_HOSTBASED_SERVICE,
 403                                  &server_name);
 404
 405   if (GSS_ERROR(major_status))
 406   {
 407 #  ifdef DEBUG
 408     DEBUG_gss_printf(major_status, minor_status, "gss_import_name() failed");
 409 #  endif /* DEBUG */
 410
 411     return (NULL);
 412   }
 413
 414   return (server_name);
 415 }
 416 #endif /* HAVE_GSSAPI */
 417
 418
 419 /*
 420  * 'cups_local_auth()' - Get the local authorization certificate if
 421  *                       available/applicable...
 422  */
 423
 424 static int                              /* O - 0 if available */
 425                                         /*     1 if not  available */
 426                                         /*    -1 error */
 427 cups_local_auth(http_t *http)           /* I - HTTP connection to server */
 428 {
 429 #if defined(WIN32) || defined(__EMX__)
 430  /*
 431   * Currently WIN32 and OS-2 do not support the CUPS server...
 432   */
 433
 434   return (-1);
 435 #else
 436   int                   pid;            /* Current process ID */
 437   FILE                  *fp;            /* Certificate file */
 438   char                  filename[1024], /* Certificate filename */
 439                         certificate[33];/* Certificate string */
 440   _cups_globals_t *cg = _cupsGlobals(); /* Global data */
 441 #if defined(HAVE_AUTHORIZATION_H)
 442   OSStatus              status;         /* Status */
 443   AuthorizationItem     auth_right;     /* Authorization right */
 444   AuthorizationRights   auth_rights;    /* Authorization rights */
 445   AuthorizationFlags    auth_flags;     /* Authorization flags */
 446   AuthorizationExternalForm auth_extrn; /* Authorization ref external */
 447   char                  auth_key[1024]; /* Buffer */
 448   char                  buffer[1024];   /* Buffer */
 449 #endif /* HAVE_AUTHORIZATION_H */
 450
 451
 452   DEBUG_printf(("cups_local_auth(http=%p) hostaddr=%s, hostname=\"%s\"\n",
 453                 http, httpAddrString(http->hostaddr, filename, sizeof(filename)), http->hostname));
 454
 455  /*
 456   * See if we are accessing localhost...
 457   */
 458
 459   if (!httpAddrLocalhost(http->hostaddr) &&
 460       strcasecmp(http->hostname, "localhost") != 0)
 461   {
 462     DEBUG_puts("cups_local_auth: Not a local connection!");
 463     return (-1);
 464   }
 465
 466 #if defined(HAVE_AUTHORIZATION_H)
 467  /*
 468   * Delete any previous authorization reference...
 469   */
 470
 471   if (cg->auth_ref)
 472   {
 473     AuthorizationFree(cg->auth_ref, kAuthorizationFlagDefaults);
 474     cg->auth_ref = NULL;
 475   }
 476
 477   if (httpGetSubField2(http, HTTP_FIELD_WWW_AUTHENTICATE, "authkey",
 478                        auth_key, sizeof(auth_key)))
 479   {
 480     status = AuthorizationCreate(NULL, kAuthorizationEmptyEnvironment,
 481                                  kAuthorizationFlagDefaults, &cg->auth_ref);
 482     if (status != errAuthorizationSuccess)
 483     {
 484       DEBUG_printf(("cups_local_auth: AuthorizationCreate() returned %d (%s)\n",
 485                     (int)status, cssmErrorString(status)));
 486       return (-1);
 487     }
 488
 489     auth_right.name        = auth_key;
 490     auth_right.valueLength = 0;
 491     auth_right.value       = NULL;
 492     auth_right.flags       = 0;
 493
 494     auth_rights.count = 1;
 495     auth_rights.items = &auth_right;
 496
 497     auth_flags = kAuthorizationFlagDefaults |
 498                  kAuthorizationFlagPreAuthorize |
 499                  kAuthorizationFlagInteractionAllowed |
 500                  kAuthorizationFlagExtendRights;
 501
 502     status = AuthorizationCopyRights(cg->auth_ref, &auth_rights,
 503                                      kAuthorizationEmptyEnvironment,
 504                                      auth_flags, NULL);
 505     if (status == errAuthorizationSuccess)
 506       status = AuthorizationMakeExternalForm(cg->auth_ref, &auth_extrn);
 507
 508     if (status == errAuthorizationSuccess)
 509     {
 510      /*
 511       * Set the authorization string and return...
 512       */
 513
 514       httpEncode64_2(buffer, sizeof(buffer), (void *)&auth_extrn,
 515                      sizeof(auth_extrn));
 516
 517       http->authstring = malloc(strlen(buffer) + 9);
 518       sprintf(http->authstring, "AuthRef %s", buffer);
 519
 520       /* Copy back to _authstring for backwards compatibility */
 521       strlcpy(http->_authstring, http->authstring, sizeof(http->_authstring));
 522
 523       DEBUG_printf(("cups_local_auth: Returning authstring = \"%s\"\n",
 524                     http->authstring));
 525       return (0);
 526     }
 527     else if (status == errAuthorizationCanceled)
 528       return (-1);
 529
 530     DEBUG_printf(("cups_local_auth: AuthorizationCopyRights() returned %d (%s)\n",
 531                   (int)status, cssmErrorString(status)));
 532
 533   /*
 534    * Fall through to try certificates...
 535    */
 536   }
 537 #endif /* HAVE_AUTHORIZATION_H */
 538
 539  /*
 540   * Try opening a certificate file for this PID.  If that fails,
 541   * try the root certificate...
 542   */
 543
 544   pid = getpid();
 545   snprintf(filename, sizeof(filename), "%s/certs/%d", cg->cups_statedir, pid);
 546   if ((fp = fopen(filename, "r")) == NULL && pid > 0)
 547   {
 548     DEBUG_printf(("cups_local_auth: Unable to open file %s: %s\n",
 549                   filename, strerror(errno)));
 550
 551     snprintf(filename, sizeof(filename), "%s/certs/0", cg->cups_statedir);
 552     fp = fopen(filename, "r");
 553   }
 554
 555   if (fp)
 556   {
 557    /*
 558     * Read the certificate from the file...
 559     */
 560
 561     fgets(certificate, sizeof(certificate), fp);
 562     fclose(fp);
 563
 564    /*
 565     * Set the authorization string and return...
 566     */
 567
 568     http->authstring = malloc(strlen(certificate) + 10);
 569     sprintf(http->authstring, "Local %s", certificate);
 570
 571     /* Copy back to _authstring for backwards compatibility */
 572     strlcpy(http->_authstring, http->authstring, sizeof(http->_authstring));
 573
 574     DEBUG_printf(("cups_local_auth: Returning authstring = \"%s\"\n",
 575                   http->authstring));
 576
 577     return (0);
 578   }
 579
 580   return (1);
 581 #endif /* WIN32 || __EMX__ */
 582 }
 583
 584
 585 /*
 586  * End of "$Id: auth.c 6397 2007-03-25 23:33:32Z mike $".
 587  */