cups/auth.c

   1 /*
   2  * "$Id$"
   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
  56 /*
  57  * Local functions...
  58  */
  59
  60 #ifdef HAVE_GSSAPI
  61 #  ifdef DEBUG
  62 static void     DEBUG_gss_printf(OM_uint32 major_status, OM_uint32 minor_status,
  63                                  const char *message);
  64 #  endif /* DEBUG  */
  65 static gss_name_t cups_get_gss_creds(http_t *http, const char *service_name);
  66 #endif /* HAVE_GSSAPI */
  67 static int      cups_local_auth(http_t *http);
  68
  69
  70 /*
  71  * 'cupsDoAuthentication()' - Authenticate a request.
  72  *
  73  * This function should be called in response to a HTTP_UNAUTHORIZED
  74  * status, prior to resubmitting your request.
  75  *
  76  * @since CUPS 1.1.20@
  77  */
  78
  79 int                                     /* O - 0 on success, -1 on error */
  80 cupsDoAuthentication(http_t     *http,  /* I - HTTP connection to server */
  81                      const char *method,/* I - Request method (GET, POST, PUT) */
  82                      const char *resource)
  83                                         /* I - Resource path */
  84 {
  85   const char    *password;              /* Password string */
  86   char          prompt[1024],           /* Prompt for user */
  87                 realm[HTTP_MAX_VALUE],  /* realm="xyz" string */
  88                 nonce[HTTP_MAX_VALUE],  /* nonce="xyz" string */
  89                 encode[2048];           /* Encoded username:password */
  90   _cups_globals_t *cg;                  /* Global data */
  91
  92
  93   DEBUG_printf(("cupsDoAuthentication(http=%p, method=\"%s\", resource=\"%s\")\n",
  94                 http, method, resource));
  95   DEBUG_printf(("cupsDoAuthentication: digest_tries=%d, userpass=\"%s\"\n",
  96                 http->digest_tries, http->userpass));
  97   DEBUG_printf(("cupsDoAuthentication: WWW-Authenticate=\"%s\"\n",
  98                 httpGetField(http, HTTP_FIELD_WWW_AUTHENTICATE)));
  99
 100  /*
 101   * Clear the current authentication string...
 102   */
 103
 104   http->_authstring[0] = '\0';
 105
 106   if (http->authstring && http->authstring != http->_authstring)
 107     free(http->authstring);
 108
 109   http->authstring = http->_authstring;
 110
 111  /*
 112   * See if we can do local authentication...
 113   */
 114
 115   if (http->digest_tries < 3 && !cups_local_auth(http))
 116   {
 117     DEBUG_printf(("cupsDoAuthentication: authstring=\"%s\"\n", http->authstring));
 118
 119     if (http->status == HTTP_UNAUTHORIZED)
 120       http->digest_tries ++;
 121
 122     return (0);
 123   }
 124
 125  /*
 126   * Nope, see if we should retry the current username:password...
 127   */
 128
 129   if ((http->digest_tries > 1 || !http->userpass[0]) &&
 130       strncmp(http->fields[HTTP_FIELD_WWW_AUTHENTICATE], "Negotiate", 9))
 131   {
 132    /*
 133     * Nope - get a new password from the user...
 134     */
 135
 136     cg = _cupsGlobals();
 137
 138     if (!cg->lang_default)
 139       cg->lang_default = cupsLangDefault();
 140
 141     snprintf(prompt, sizeof(prompt),
 142              _cupsLangString(cg->lang_default, _("Password for %s on %s? ")),
 143              cupsUser(),
 144              http->hostname[0] == '/' ? "localhost" : http->hostname);
 145
 146     http->digest_tries  = strncasecmp(http->fields[HTTP_FIELD_WWW_AUTHENTICATE],
 147                                       "Digest", 5) != 0;
 148     http->userpass[0]   = '\0';
 149
 150     if ((password = cupsGetPassword(prompt)) == NULL)
 151       return (-1);
 152
 153     if (!password[0])
 154       return (-1);
 155
 156     snprintf(http->userpass, sizeof(http->userpass), "%s:%s", cupsUser(),
 157              password);
 158   }
 159   else if (http->status == HTTP_UNAUTHORIZED)
 160     http->digest_tries ++;
 161
 162  /*
 163   * Got a password; encode it for the server...
 164   */
 165
 166   if (!strncmp(http->fields[HTTP_FIELD_WWW_AUTHENTICATE], "Negotiate", 9))
 167   {
 168 #ifdef HAVE_GSSAPI
 169    /*
 170     * Kerberos authentication...
 171     */
 172
 173     OM_uint32           minor_status,   /* Minor status code */
 174                         major_status;   /* Major status code */
 175     gss_buffer_desc     output_token = GSS_C_EMPTY_BUFFER,
 176                                         /* Output token */
 177                         input_token = GSS_C_EMPTY_BUFFER;
 178                                         /* Input token */
 179     char                *gss_service_name;
 180                                         /* GSS service name */
 181     const char          *authorization;
 182                                         /* Pointer into Authorization string */
 183
 184
 185     if (http->gssname == GSS_C_NO_NAME)
 186     {
 187       if ((gss_service_name = getenv("CUPS_GSSSERVICENAME")) == NULL)
 188         gss_service_name = CUPS_DEFAULT_GSSSERVICENAME;
 189       else
 190         DEBUG_puts("cupsDoAuthentication: GSS service name set via environment");
 191
 192       http->gssname = cups_get_gss_creds(http, gss_service_name);
 193     }
 194
 195    /*
 196     * Find the start of the Kerberos input token...
 197     */
 198
 199     authorization = httpGetField(http, HTTP_FIELD_WWW_AUTHENTICATE);
 200
 201     authorization += 9;
 202     while (*authorization && isspace(*authorization & 255))
 203       authorization ++;
 204
 205     if (*authorization)
 206     {
 207      /*
 208       * For SPNEGO, this is where we'll feed the server's authorization data
 209       * back into gss via input_token...
 210       */
 211     }
 212     else
 213     {
 214       if (http->gssctx != GSS_C_NO_CONTEXT)
 215       {
 216         major_status = gss_delete_sec_context(&minor_status, &http->gssctx,
 217                                               GSS_C_NO_BUFFER);
 218         http->gssctx = GSS_C_NO_CONTEXT;
 219       }
 220     }
 221
 222     major_status  = gss_init_sec_context(&minor_status, GSS_C_NO_CREDENTIAL,
 223                                          &http->gssctx,
 224                                          http->gssname, http->gssmech,
 225                                          GSS_C_MUTUAL_FLAG, GSS_C_INDEFINITE,
 226                                          GSS_C_NO_CHANNEL_BINDINGS,
 227                                          &input_token, &http->gssmech,
 228                                          &output_token, NULL, NULL);
 229
 230     if (input_token.value)
 231       free(input_token.value);
 232
 233     if (GSS_ERROR(major_status))
 234     {
 235 #  ifdef DEBUG
 236       DEBUG_gss_printf(major_status, minor_status,
 237                        "Unable to initialise security context");
 238 #  endif /* DEBUG */
 239       return (-1);
 240     }
 241
 242 #  ifdef DEBUG
 243     if (major_status == GSS_S_CONTINUE_NEEDED)
 244       DEBUG_gss_printf(major_status, minor_status, "Continuation needed!");
 245 #  endif /* DEBUG */
 246
 247     if (output_token.length)
 248     {
 249       httpEncode64_2(encode, sizeof(encode), output_token.value,
 250                      output_token.length);
 251
 252       http->authstring = malloc(strlen(encode) + 11);
 253       sprintf(http->authstring, "Negotiate %s", encode); /* Safe because allocated */
 254
 255       major_status = gss_release_buffer(&minor_status, &output_token);
 256     }
 257
 258    /*
 259     * Copy back what we can to _authstring for backwards compatibility...
 260     */
 261
 262     strlcpy(http->_authstring, http->authstring, sizeof(http->_authstring));
 263 #endif /* HAVE_GSSAPI */
 264   }
 265   else if (strncmp(http->fields[HTTP_FIELD_WWW_AUTHENTICATE], "Digest", 6))
 266   {
 267    /*
 268     * Basic authentication...
 269     */
 270
 271     httpEncode64_2(encode, sizeof(encode), http->userpass,
 272                    (int)strlen(http->userpass));
 273     snprintf(http->_authstring, sizeof(http->_authstring), "Basic %s", encode);
 274   }
 275   else
 276   {
 277    /*
 278     * Digest authentication...
 279     */
 280
 281     httpGetSubField(http, HTTP_FIELD_WWW_AUTHENTICATE, "realm", realm);
 282     httpGetSubField(http, HTTP_FIELD_WWW_AUTHENTICATE, "nonce", nonce);
 283
 284     httpMD5(cupsUser(), realm, strchr(http->userpass, ':') + 1, encode);
 285     httpMD5Final(nonce, method, resource, encode);
 286     snprintf(http->_authstring, sizeof(http->_authstring),
 287              "Digest username=\"%s\", realm=\"%s\", nonce=\"%s\", "
 288              "uri=\"%s\", response=\"%s\"", cupsUser(), realm, nonce,
 289              resource, encode);
 290   }
 291
 292   DEBUG_printf(("cupsDoAuthentication: authstring=\"%s\"\n", http->authstring));
 293
 294   return (0);
 295 }
 296
 297
 298 #ifdef HAVE_GSSAPI
 299 #  ifdef DEBUG
 300 /*
 301  * 'DEBUG_gss_printf()' - Show debug error messages from GSSAPI...
 302  */
 303
 304 static void
 305 DEBUG_gss_printf(OM_uint32 major_status,/* I - Major status code */
 306                  OM_uint32 minor_status,/* I - Minor status code */
 307                  const char *message)   /* I - Prefix for error message */
 308 {
 309   OM_uint32     err_major_status,       /* Major status code for display */
 310                 err_minor_status;       /* Minor status code for display */
 311   OM_uint32     msg_ctx;                /* Message context */
 312   gss_buffer_desc major_status_string = GSS_C_EMPTY_BUFFER,
 313                                         /* Major status message */
 314                 minor_status_string = GSS_C_EMPTY_BUFFER;
 315                                         /* Minor status message */
 316
 317
 318   msg_ctx          = 0;
 319   err_major_status = gss_display_status(&err_minor_status,
 320                                         major_status,
 321                                         GSS_C_GSS_CODE,
 322                                         GSS_C_NO_OID,
 323                                         &msg_ctx,
 324                                         &major_status_string);
 325
 326   if (!GSS_ERROR(err_major_status))
 327     err_major_status = gss_display_status(&err_minor_status,
 328                                           minor_status,
 329                                           GSS_C_MECH_CODE,
 330                                           GSS_C_NULL_OID,
 331                                           &msg_ctx,
 332                                           &minor_status_string);
 333
 334   printf("%s: %s, %s\n", message, (char *)major_status_string.value,
 335          (char *)minor_status_string.value);
 336
 337   gss_release_buffer(&err_minor_status, &major_status_string);
 338   gss_release_buffer(&err_minor_status, &minor_status_string);
 339 }
 340 #  endif /* DEBUG */
 341
 342
 343 /*
 344  * 'cups_get_gss_creds()' - Get CUPS service credentials for authentication.
 345  */
 346
 347 static gss_name_t                       /* O - Server name */
 348 cups_get_gss_creds(
 349     http_t     *http,                   /* I - Connection to server */
 350     const char *service_name)           /* I - Service name */
 351 {
 352   gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
 353                                         /* Service token */
 354   OM_uint32     major_status,           /* Major status code */
 355                 minor_status;           /* Minor status code */
 356   gss_name_t    server_name;            /* Server name */
 357   char          buf[1024],              /* Name buffer */
 358                 fqdn[HTTP_MAX_URI];     /* Server name buffer */
 359
 360
 361  /*
 362   * Get a server name we can use for authentication purposes...
 363   */
 364
 365   snprintf(buf, sizeof(buf), "%s@%s", service_name,
 366            httpGetHostname(http, fqdn, sizeof(fqdn)));
 367
 368   token.value  = buf;
 369   token.length = strlen(buf);
 370   server_name  = GSS_C_NO_NAME;
 371   major_status = gss_import_name(&minor_status, &token,
 372                                  GSS_C_NT_HOSTBASED_SERVICE,
 373                                  &server_name);
 374
 375   if (GSS_ERROR(major_status))
 376   {
 377 #  ifdef DEBUG
 378     DEBUG_gss_printf(major_status, minor_status, "gss_import_name() failed");
 379 #  endif /* DEBUG */
 380
 381     return (NULL);
 382   }
 383
 384   return (server_name);
 385 }
 386 #endif /* HAVE_GSSAPI */
 387
 388
 389 /*
 390  * 'cups_local_auth()' - Get the local authorization certificate if
 391  *                       available/applicable...
 392  */
 393
 394 static int                              /* O - 0 if available, -1 if not */
 395 cups_local_auth(http_t *http)           /* I - HTTP connection to server */
 396 {
 397 #if defined(WIN32) || defined(__EMX__)
 398  /*
 399   * Currently WIN32 and OS-2 do not support the CUPS server...
 400   */
 401
 402   return (-1);
 403 #else
 404   int           pid;                    /* Current process ID */
 405   FILE          *fp;                    /* Certificate file */
 406   char          filename[1024],         /* Certificate filename */
 407                 certificate[33];        /* Certificate string */
 408   _cups_globals_t *cg = _cupsGlobals(); /* Global data */
 409
 410
 411   DEBUG_printf(("cups_local_auth(http=%p) hostaddr=%s, hostname=\"%s\"\n",
 412                 http, httpAddrString(http->hostaddr, filename, sizeof(filename)), http->hostname));
 413
 414  /*
 415   * See if we are accessing localhost...
 416   */
 417
 418   if (!httpAddrLocalhost(http->hostaddr) &&
 419       strcasecmp(http->hostname, "localhost") != 0)
 420   {
 421     DEBUG_puts("cups_local_auth: Not a local connection!");
 422     return (-1);
 423   }
 424
 425  /*
 426   * Try opening a certificate file for this PID.  If that fails,
 427   * try the root certificate...
 428   */
 429
 430   pid = getpid();
 431   snprintf(filename, sizeof(filename), "%s/certs/%d", cg->cups_statedir, pid);
 432   if ((fp = fopen(filename, "r")) == NULL && pid > 0)
 433   {
 434     DEBUG_printf(("cups_local_auth: Unable to open file %s: %s\n",
 435                   filename, strerror(errno)));
 436
 437     snprintf(filename, sizeof(filename), "%s/certs/0", cg->cups_statedir);
 438     fp = fopen(filename, "r");
 439   }
 440
 441   if (fp == NULL)
 442   {
 443     DEBUG_printf(("cups_local_auth: Unable to open file %s: %s\n",
 444                   filename, strerror(errno)));
 445     return (-1);
 446   }
 447
 448  /*
 449   * Read the certificate from the file...
 450   */
 451
 452   fgets(certificate, sizeof(certificate), fp);
 453   fclose(fp);
 454
 455  /*
 456   * Set the authorization string and return...
 457   */
 458
 459   http->authstring = malloc(strlen(certificate) + 10);
 460   sprintf(http->authstring, "Local %s", certificate);
 461
 462   /* Copy back to _authstring for backwards compatibility */
 463   strlcpy(http->_authstring, http->authstring, sizeof(http->_authstring));
 464
 465   DEBUG_printf(("cups_local_auth: Returning authstring = \"%s\"\n",
 466                 http->authstring));
 467
 468   return (0);
 469 #endif /* WIN32 || __EMX__ */
 470 }
 471
 472
 473 /*
 474  * End of "$Id$".
 475  */