cups/auth.c

   1 /*
   2  * Authentication functions for CUPS.
   3  *
   4  * Copyright 2007-2019 by Apple Inc.
   5  * Copyright 1997-2007 by Easy Software Products.
   6  *
   7  * This file contains Kerberos support code, copyright 2006 by
   8  * Jelmer Vernooij.
   9  *
  10  * Licensed under Apache License v2.0.  See the file "LICENSE" for more information.
  11  */
  12
  13 /*
  14  * Include necessary headers...
  15  */
  16
  17 #include "cups-private.h"
  18 #include "debug-internal.h"
  19 #include <fcntl.h>
  20 #include <sys/stat.h>
  21 #if defined(_WIN32) || defined(__EMX__)
  22 #  include <io.h>
  23 #else
  24 #  include <unistd.h>
  25 #endif /* _WIN32 || __EMX__ */
  26
  27 #if HAVE_AUTHORIZATION_H
  28 #  include <Security/Authorization.h>
  29 #endif /* HAVE_AUTHORIZATION_H */
  30
  31 #if defined(SO_PEERCRED) && defined(AF_LOCAL)
  32 #  include <pwd.h>
  33 #endif /* SO_PEERCRED && AF_LOCAL */
  34
  35
  36 /*
  37  * Local functions...
  38  */
  39
  40 static const char       *cups_auth_find(const char *www_authenticate, const char *scheme);
  41 static const char       *cups_auth_param(const char *scheme, const char *name, char *value, size_t valsize);
  42 static const char       *cups_auth_scheme(const char *www_authenticate, char *scheme, size_t schemesize);
  43
  44 #ifdef HAVE_GSSAPI
  45 #  define CUPS_GSS_OK   0               /* Successfully set credentials */
  46 #  define CUPS_GSS_NONE -1              /* No credentials */
  47 #  define CUPS_GSS_FAIL -2              /* Failed credentials/authentication */
  48 #  ifdef HAVE_GSS_ACQUIRE_CRED_EX_F
  49 #    ifdef HAVE_GSS_GSSAPI_SPI_H
  50 #      include <GSS/gssapi_spi.h>
  51 #    else
  52 #      define GSS_AUTH_IDENTITY_TYPE_1 1
  53 #      define gss_acquire_cred_ex_f __ApplePrivate_gss_acquire_cred_ex_f
  54 typedef struct gss_auth_identity /* @private@ */
  55 {
  56   uint32_t type;
  57   uint32_t flags;
  58   char *username;
  59   char *realm;
  60   char *password;
  61   gss_buffer_t *credentialsRef;
  62 } gss_auth_identity_desc;
  63 extern OM_uint32 gss_acquire_cred_ex_f(gss_status_id_t, const gss_name_t,
  64                                        OM_uint32, OM_uint32, const gss_OID,
  65                                        gss_cred_usage_t, gss_auth_identity_t,
  66                                        void *, void (*)(void *, OM_uint32,
  67                                                         gss_status_id_t,
  68                                                         gss_cred_id_t,
  69                                                         gss_OID_set,
  70                                                         OM_uint32));
  71 #    endif /* HAVE_GSS_GSSAPI_SPI_H */
  72 #    include <dispatch/dispatch.h>
  73 typedef struct _cups_gss_acquire_s      /* Acquire callback data */
  74 {
  75   dispatch_semaphore_t  sem;            /* Synchronization semaphore */
  76   OM_uint32             major;          /* Returned status code */
  77   gss_cred_id_t         creds;          /* Returned credentials */
  78 } _cups_gss_acquire_t;
  79
  80 static void     cups_gss_acquire(void *ctx, OM_uint32 major,
  81                                  gss_status_id_t status,
  82                                  gss_cred_id_t creds, gss_OID_set oids,
  83                                  OM_uint32 time_rec);
  84 #  endif /* HAVE_GSS_ACQUIRE_CRED_EX_F */
  85 static gss_name_t cups_gss_getname(http_t *http, const char *service_name);
  86 #  ifdef DEBUG
  87 static void     cups_gss_printf(OM_uint32 major_status, OM_uint32 minor_status,
  88                                 const char *message);
  89 #  else
  90 #    define     cups_gss_printf(major, minor, message)
  91 #  endif /* DEBUG */
  92 #endif /* HAVE_GSSAPI */
  93 static int      cups_local_auth(http_t *http);
  94
  95
  96 /*
  97  * 'cupsDoAuthentication()' - Authenticate a request.
  98  *
  99  * This function should be called in response to a @code HTTP_STATUS_UNAUTHORIZED@
 100  * status, prior to resubmitting your request.
 101  *
 102  * @since CUPS 1.1.20/macOS 10.4@
 103  */
 104
 105 int                                     /* O - 0 on success, -1 on error */
 106 cupsDoAuthentication(
 107     http_t     *http,                   /* I - Connection to server or @code CUPS_HTTP_DEFAULT@ */
 108     const char *method,                 /* I - Request method ("GET", "POST", "PUT") */
 109     const char *resource)               /* I - Resource path */
 110 {
 111   const char    *password,              /* Password string */
 112                 *www_auth,              /* WWW-Authenticate header */
 113                 *schemedata;            /* Scheme-specific data */
 114   char          scheme[256],            /* Scheme name */
 115                 prompt[1024];           /* Prompt for user */
 116   int           localauth;              /* Local authentication result */
 117   _cups_globals_t *cg;                  /* Global data */
 118
 119
 120   DEBUG_printf(("cupsDoAuthentication(http=%p, method=\"%s\", resource=\"%s\")", (void *)http, method, resource));
 121
 122   if (!http)
 123     http = _cupsConnect();
 124
 125   if (!http || !method || !resource)
 126     return (-1);
 127
 128   DEBUG_printf(("2cupsDoAuthentication: digest_tries=%d, userpass=\"%s\"",
 129                 http->digest_tries, http->userpass));
 130   DEBUG_printf(("2cupsDoAuthentication: WWW-Authenticate=\"%s\"",
 131                 httpGetField(http, HTTP_FIELD_WWW_AUTHENTICATE)));
 132
 133  /*
 134   * Clear the current authentication string...
 135   */
 136
 137   httpSetAuthString(http, NULL, NULL);
 138
 139  /*
 140   * See if we can do local authentication...
 141   */
 142
 143   if (http->digest_tries < 3)
 144   {
 145     if ((localauth = cups_local_auth(http)) == 0)
 146     {
 147       DEBUG_printf(("2cupsDoAuthentication: authstring=\"%s\"",
 148                     http->authstring));
 149
 150       if (http->status == HTTP_STATUS_UNAUTHORIZED)
 151         http->digest_tries ++;
 152
 153       return (0);
 154     }
 155     else if (localauth == -1)
 156     {
 157       http->status = HTTP_STATUS_CUPS_AUTHORIZATION_CANCELED;
 158       return (-1);                      /* Error or canceled */
 159     }
 160   }
 161
 162  /*
 163   * Nope, loop through the authentication schemes to find the first we support.
 164   */
 165
 166   www_auth = httpGetField(http, HTTP_FIELD_WWW_AUTHENTICATE);
 167
 168   for (schemedata = cups_auth_scheme(www_auth, scheme, sizeof(scheme)); schemedata; schemedata = cups_auth_scheme(schemedata + strlen(scheme), scheme, sizeof(scheme)))
 169   {
 170    /*
 171     * Check the scheme name...
 172     */
 173
 174     DEBUG_printf(("2cupsDoAuthentication: Trying scheme \"%s\"...", scheme));
 175
 176 #ifdef HAVE_GSSAPI
 177     if (!_cups_strcasecmp(scheme, "Negotiate"))
 178     {
 179      /*
 180       * Kerberos authentication...
 181       */
 182
 183       int gss_status;                   /* Auth status */
 184
 185       if ((gss_status = _cupsSetNegotiateAuthString(http, method, resource)) == CUPS_GSS_FAIL)
 186       {
 187         DEBUG_puts("1cupsDoAuthentication: Negotiate failed.");
 188         http->status = HTTP_STATUS_CUPS_AUTHORIZATION_CANCELED;
 189         return (-1);
 190       }
 191       else if (gss_status == CUPS_GSS_NONE)
 192       {
 193         DEBUG_puts("2cupsDoAuthentication: No credentials for Negotiate.");
 194         continue;
 195       }
 196       else
 197       {
 198         DEBUG_puts("2cupsDoAuthentication: Using Negotiate.");
 199         break;
 200       }
 201     }
 202     else
 203 #endif /* HAVE_GSSAPI */
 204     if (_cups_strcasecmp(scheme, "Basic") && _cups_strcasecmp(scheme, "Digest"))
 205     {
 206      /*
 207       * Other schemes not yet supported...
 208       */
 209
 210       DEBUG_printf(("2cupsDoAuthentication: Scheme \"%s\" not yet supported.", scheme));
 211       continue;
 212     }
 213
 214    /*
 215     * See if we should retry the current username:password...
 216     */
 217
 218     if ((http->digest_tries > 1 || !http->userpass[0]) && (!_cups_strcasecmp(scheme, "Basic") || (!_cups_strcasecmp(scheme, "Digest"))))
 219     {
 220      /*
 221       * Nope - get a new password from the user...
 222       */
 223
 224       char default_username[HTTP_MAX_VALUE];
 225                                         /* Default username */
 226
 227       cg = _cupsGlobals();
 228
 229       if (!cg->lang_default)
 230         cg->lang_default = cupsLangDefault();
 231
 232       if (cups_auth_param(schemedata, "username", default_username, sizeof(default_username)))
 233         cupsSetUser(default_username);
 234
 235       snprintf(prompt, sizeof(prompt), _cupsLangString(cg->lang_default, _("Password for %s on %s? ")), cupsUser(), http->hostname[0] == '/' ? "localhost" : http->hostname);
 236
 237       http->digest_tries  = _cups_strncasecmp(scheme, "Digest", 6) != 0;
 238       http->userpass[0]   = '\0';
 239
 240       if ((password = cupsGetPassword2(prompt, http, method, resource)) == NULL)
 241       {
 242         DEBUG_puts("1cupsDoAuthentication: User canceled password request.");
 243         http->status = HTTP_STATUS_CUPS_AUTHORIZATION_CANCELED;
 244         return (-1);
 245       }
 246
 247       snprintf(http->userpass, sizeof(http->userpass), "%s:%s", cupsUser(), password);
 248     }
 249     else if (http->status == HTTP_STATUS_UNAUTHORIZED)
 250       http->digest_tries ++;
 251
 252     if (http->status == HTTP_STATUS_UNAUTHORIZED && http->digest_tries >= 3)
 253     {
 254       DEBUG_printf(("1cupsDoAuthentication: Too many authentication tries (%d)", http->digest_tries));
 255
 256       http->status = HTTP_STATUS_CUPS_AUTHORIZATION_CANCELED;
 257       return (-1);
 258     }
 259
 260    /*
 261     * Got a password; encode it for the server...
 262     */
 263
 264     if (!_cups_strcasecmp(scheme, "Basic"))
 265     {
 266      /*
 267       * Basic authentication...
 268       */
 269
 270       char      encode[256];            /* Base64 buffer */
 271
 272       DEBUG_puts("2cupsDoAuthentication: Using Basic.");
 273       httpEncode64_2(encode, sizeof(encode), http->userpass, (int)strlen(http->userpass));
 274       httpSetAuthString(http, "Basic", encode);
 275       break;
 276     }
 277     else if (!_cups_strcasecmp(scheme, "Digest"))
 278     {
 279      /*
 280       * Digest authentication...
 281       */
 282
 283       char nonce[HTTP_MAX_VALUE];       /* nonce="xyz" string */
 284
 285       cups_auth_param(schemedata, "algorithm", http->algorithm, sizeof(http->algorithm));
 286       cups_auth_param(schemedata, "opaque", http->opaque, sizeof(http->opaque));
 287       cups_auth_param(schemedata, "nonce", nonce, sizeof(nonce));
 288       cups_auth_param(schemedata, "realm", http->realm, sizeof(http->realm));
 289
 290       if (_httpSetDigestAuthString(http, nonce, method, resource))
 291       {
 292         DEBUG_puts("2cupsDoAuthentication: Using Digest.");
 293         break;
 294       }
 295     }
 296   }
 297
 298   if (http->authstring)
 299   {
 300     DEBUG_printf(("1cupsDoAuthentication: authstring=\"%s\".", http->authstring));
 301
 302     return (0);
 303   }
 304   else
 305   {
 306     DEBUG_puts("1cupsDoAuthentication: No supported schemes.");
 307     http->status = HTTP_STATUS_CUPS_AUTHORIZATION_CANCELED;
 308
 309     return (-1);
 310   }
 311 }
 312
 313
 314 #ifdef HAVE_GSSAPI
 315 /*
 316  * '_cupsSetNegotiateAuthString()' - Set the Kerberos authentication string.
 317  */
 318
 319 int                                     /* O - 0 on success, negative on error */
 320 _cupsSetNegotiateAuthString(
 321     http_t     *http,                   /* I - Connection to server */
 322     const char *method,                 /* I - Request method ("GET", "POST", "PUT") */
 323     const char *resource)               /* I - Resource path */
 324 {
 325   OM_uint32     minor_status,           /* Minor status code */
 326                 major_status;           /* Major status code */
 327   gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER;
 328                                         /* Output token */
 329
 330
 331   (void)method;
 332   (void)resource;
 333
 334 #  ifdef __APPLE__
 335  /*
 336   * If the weak-linked GSSAPI/Kerberos library is not present, don't try
 337   * to use it...
 338   */
 339
 340   if (&gss_init_sec_context == NULL)
 341   {
 342     DEBUG_puts("1_cupsSetNegotiateAuthString: Weak-linked GSSAPI/Kerberos "
 343                "framework is not present");
 344     return (CUPS_GSS_NONE);
 345   }
 346 #  endif /* __APPLE__ */
 347
 348   if (!strcmp(http->hostname, "localhost") || http->hostname[0] == '/' || isdigit(http->hostname[0] & 255) || !strchr(http->hostname, '.'))
 349   {
 350     DEBUG_printf(("1_cupsSetNegotiateAuthString: Kerberos not available for host \"%s\".", http->hostname));
 351     return (CUPS_GSS_NONE);
 352   }
 353
 354   if (http->gssname == GSS_C_NO_NAME)
 355   {
 356     http->gssname = cups_gss_getname(http, _cupsGSSServiceName());
 357   }
 358
 359   if (http->gssctx != GSS_C_NO_CONTEXT)
 360   {
 361     gss_delete_sec_context(&minor_status, &http->gssctx, GSS_C_NO_BUFFER);
 362     http->gssctx = GSS_C_NO_CONTEXT;
 363   }
 364
 365   major_status = gss_init_sec_context(&minor_status, GSS_C_NO_CREDENTIAL,
 366                                       &http->gssctx,
 367                                       http->gssname, http->gssmech,
 368                                       GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG,
 369                                       GSS_C_INDEFINITE,
 370                                       GSS_C_NO_CHANNEL_BINDINGS,
 371                                       GSS_C_NO_BUFFER, &http->gssmech,
 372                                       &output_token, NULL, NULL);
 373
 374 #  ifdef HAVE_GSS_ACQUIRE_CRED_EX_F
 375   if (major_status == GSS_S_NO_CRED)
 376   {
 377    /*
 378     * Ask the user for credentials...
 379     */
 380
 381     char                prompt[1024],   /* Prompt for user */
 382                         userbuf[256];   /* Kerberos username */
 383     const char          *username,      /* Username string */
 384                         *password;      /* Password string */
 385     _cups_gss_acquire_t data;           /* Callback data */
 386     gss_auth_identity_desc identity;    /* Kerberos user identity */
 387     _cups_globals_t     *cg = _cupsGlobals();
 388                                         /* Per-thread global data */
 389
 390     if (!cg->lang_default)
 391       cg->lang_default = cupsLangDefault();
 392
 393     snprintf(prompt, sizeof(prompt),
 394              _cupsLangString(cg->lang_default, _("Password for %s on %s? ")),
 395              cupsUser(), http->gsshost);
 396
 397     if ((password = cupsGetPassword2(prompt, http, method, resource)) == NULL)
 398       return (CUPS_GSS_FAIL);
 399
 400    /*
 401     * Try to acquire credentials...
 402     */
 403
 404     username = cupsUser();
 405     if (!strchr(username, '@'))
 406     {
 407       snprintf(userbuf, sizeof(userbuf), "%s@%s", username, http->gsshost);
 408       username = userbuf;
 409     }
 410
 411     identity.type           = GSS_AUTH_IDENTITY_TYPE_1;
 412     identity.flags          = 0;
 413     identity.username       = (char *)username;
 414     identity.realm          = (char *)"";
 415     identity.password       = (char *)password;
 416     identity.credentialsRef = NULL;
 417
 418     data.sem   = dispatch_semaphore_create(0);
 419     data.major = 0;
 420     data.creds = NULL;
 421
 422     if (data.sem)
 423     {
 424       major_status = gss_acquire_cred_ex_f(NULL, GSS_C_NO_NAME, 0, GSS_C_INDEFINITE, GSS_KRB5_MECHANISM, GSS_C_INITIATE, (gss_auth_identity_t)&identity, &data, cups_gss_acquire);
 425
 426       if (major_status == GSS_S_COMPLETE)
 427       {
 428         dispatch_semaphore_wait(data.sem, DISPATCH_TIME_FOREVER);
 429         major_status = data.major;
 430       }
 431
 432       dispatch_release(data.sem);
 433
 434       if (major_status == GSS_S_COMPLETE)
 435       {
 436         OM_uint32       release_minor;  /* Minor status from releasing creds */
 437
 438         major_status = gss_init_sec_context(&minor_status, data.creds,
 439                                             &http->gssctx,
 440                                             http->gssname, http->gssmech,
 441                                             GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG,
 442                                             GSS_C_INDEFINITE,
 443                                             GSS_C_NO_CHANNEL_BINDINGS,
 444                                             GSS_C_NO_BUFFER, &http->gssmech,
 445                                             &output_token, NULL, NULL);
 446         gss_release_cred(&release_minor, &data.creds);
 447       }
 448     }
 449   }
 450 #  endif /* HAVE_GSS_ACQUIRED_CRED_EX_F */
 451
 452   if (major_status == GSS_S_NO_CRED)
 453   {
 454     cups_gss_printf(major_status, minor_status, "_cupsSetNegotiateAuthString: No credentials");
 455     return (CUPS_GSS_NONE);
 456   }
 457   else if (GSS_ERROR(major_status))
 458   {
 459     cups_gss_printf(major_status, minor_status, "_cupsSetNegotiateAuthString: Unable to initialize security context");
 460     return (CUPS_GSS_FAIL);
 461   }
 462
 463 #  ifdef DEBUG
 464   else if (major_status == GSS_S_CONTINUE_NEEDED)
 465     cups_gss_printf(major_status, minor_status, "_cupsSetNegotiateAuthString: Continuation needed");
 466 #  endif /* DEBUG */
 467
 468   if (output_token.length > 0 && output_token.length <= 65536)
 469   {
 470    /*
 471     * Allocate the authorization string since Windows KDCs can have
 472     * arbitrarily large credentials...
 473     */
 474
 475     int authsize = 10 +                 /* "Negotiate " */
 476                    (((int)output_token.length * 4 / 3 + 3) & ~3) + 1;
 477                                         /* Base64 + nul */
 478
 479     httpSetAuthString(http, NULL, NULL);
 480
 481     if ((http->authstring = malloc((size_t)authsize)) == NULL)
 482     {
 483       http->authstring = http->_authstring;
 484       authsize         = sizeof(http->_authstring);
 485     }
 486
 487     strlcpy(http->authstring, "Negotiate ", (size_t)authsize);
 488     httpEncode64_2(http->authstring + 10, authsize - 10, output_token.value,
 489                    (int)output_token.length);
 490
 491     gss_release_buffer(&minor_status, &output_token);
 492   }
 493   else
 494   {
 495     DEBUG_printf(("1_cupsSetNegotiateAuthString: Kerberos credentials too "
 496                   "large - %d bytes!", (int)output_token.length));
 497     gss_release_buffer(&minor_status, &output_token);
 498
 499     return (CUPS_GSS_FAIL);
 500   }
 501
 502   return (CUPS_GSS_OK);
 503 }
 504 #endif /* HAVE_GSSAPI */
 505
 506
 507 /*
 508  * 'cups_auth_find()' - Find the named WWW-Authenticate scheme.
 509  *
 510  * The "www_authenticate" parameter points to the current position in the header.
 511  *
 512  * Returns @code NULL@ if the auth scheme is not present.
 513  */
 514
 515 static const char *                             /* O - Start of matching scheme or @code NULL@ if not found */
 516 cups_auth_find(const char *www_authenticate,    /* I - Pointer into WWW-Authenticate header */
 517                const char *scheme)              /* I - Authentication scheme */
 518 {
 519   size_t        schemelen = strlen(scheme);     /* Length of scheme */
 520
 521
 522   DEBUG_printf(("8cups_auth_find(www_authenticate=\"%s\", scheme=\"%s\"(%d))", www_authenticate, scheme, (int)schemelen));
 523
 524   while (*www_authenticate)
 525   {
 526    /*
 527     * Skip leading whitespace and commas...
 528     */
 529
 530     DEBUG_printf(("9cups_auth_find: Before whitespace: \"%s\"", www_authenticate));
 531     while (isspace(*www_authenticate & 255) || *www_authenticate == ',')
 532       www_authenticate ++;
 533     DEBUG_printf(("9cups_auth_find: After whitespace: \"%s\"", www_authenticate));
 534
 535    /*
 536     * See if this is "Scheme" followed by whitespace or the end of the string.
 537     */
 538
 539     if (!strncmp(www_authenticate, scheme, schemelen) && (isspace(www_authenticate[schemelen] & 255) || www_authenticate[schemelen] == ',' || !www_authenticate[schemelen]))
 540     {
 541      /*
 542       * Yes, this is the start of the scheme-specific information...
 543       */
 544
 545       DEBUG_printf(("9cups_auth_find: Returning \"%s\".", www_authenticate));
 546
 547       return (www_authenticate);
 548     }
 549
 550    /*
 551     * Skip the scheme name or param="value" string...
 552     */
 553
 554     while (!isspace(*www_authenticate & 255) && *www_authenticate)
 555     {
 556       if (*www_authenticate == '\"')
 557       {
 558        /*
 559         * Skip quoted value...
 560         */
 561
 562         www_authenticate ++;
 563         while (*www_authenticate && *www_authenticate != '\"')
 564           www_authenticate ++;
 565
 566         DEBUG_printf(("9cups_auth_find: After quoted: \"%s\"", www_authenticate));
 567       }
 568
 569       www_authenticate ++;
 570     }
 571
 572     DEBUG_printf(("9cups_auth_find: After skip: \"%s\"", www_authenticate));
 573   }
 574
 575   DEBUG_puts("9cups_auth_find: Returning NULL.");
 576
 577   return (NULL);
 578 }
 579
 580
 581 /*
 582  * 'cups_auth_param()' - Copy the value for the named authentication parameter,
 583  *                       if present.
 584  */
 585
 586 static const char *                             /* O - Parameter value or @code NULL@ if not present */
 587 cups_auth_param(const char *scheme,             /* I - Pointer to auth data */
 588                 const char *name,               /* I - Name of parameter */
 589                 char       *value,              /* I - Value buffer */
 590                 size_t     valsize)             /* I - Size of value buffer */
 591 {
 592   char          *valptr = value,                /* Pointer into value buffer */
 593                 *valend = value + valsize - 1;  /* Pointer to end of buffer */
 594   size_t        namelen = strlen(name);         /* Name length */
 595   int           param;                          /* Is this a parameter? */
 596
 597
 598   DEBUG_printf(("8cups_auth_param(scheme=\"%s\", name=\"%s\", value=%p, valsize=%d)", scheme, name, (void *)value, (int)valsize));
 599
 600   while (!isspace(*scheme & 255) && *scheme)
 601     scheme ++;
 602
 603   while (*scheme)
 604   {
 605     while (isspace(*scheme & 255) || *scheme == ',')
 606       scheme ++;
 607
 608     if (!strncmp(scheme, name, namelen) && scheme[namelen] == '=')
 609     {
 610      /*
 611       * Found the parameter, copy the value...
 612       */
 613
 614       scheme += namelen + 1;
 615       if (*scheme == '\"')
 616       {
 617         scheme ++;
 618
 619         while (*scheme && *scheme != '\"')
 620         {
 621           if (valptr < valend)
 622             *valptr++ = *scheme;
 623
 624           scheme ++;
 625         }
 626       }
 627       else
 628       {
 629         while (*scheme && strchr("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-._~+/=", *scheme))
 630         {
 631           if (valptr < valend)
 632             *valptr++ = *scheme;
 633
 634           scheme ++;
 635         }
 636       }
 637
 638       *valptr = '\0';
 639
 640       DEBUG_printf(("9cups_auth_param: Returning \"%s\".", value));
 641
 642       return (value);
 643     }
 644
 645    /*
 646     * Skip the param=value string...
 647     */
 648
 649     param = 0;
 650
 651     while (!isspace(*scheme & 255) && *scheme)
 652     {
 653       if (*scheme == '=')
 654         param = 1;
 655       else if (*scheme == '\"')
 656       {
 657        /*
 658         * Skip quoted value...
 659         */
 660
 661         scheme ++;
 662         while (*scheme && *scheme != '\"')
 663           scheme ++;
 664       }
 665
 666       scheme ++;
 667     }
 668
 669    /*
 670     * If this wasn't a parameter, we are at the end of this scheme's
 671     * parameters...
 672     */
 673
 674     if (!param)
 675       break;
 676   }
 677
 678   *value = '\0';
 679
 680   DEBUG_puts("9cups_auth_param: Returning NULL.");
 681
 682   return (NULL);
 683 }
 684
 685
 686 /*
 687  * 'cups_auth_scheme()' - Get the (next) WWW-Authenticate scheme.
 688  *
 689  * The "www_authenticate" parameter points to the current position in the header.
 690  *
 691  * Returns @code NULL@ if there are no (more) auth schemes present.
 692  */
 693
 694 static const char *                             /* O - Start of scheme or @code NULL@ if not found */
 695 cups_auth_scheme(const char *www_authenticate,  /* I - Pointer into WWW-Authenticate header */
 696                  char       *scheme,            /* I - Scheme name buffer */
 697                  size_t     schemesize)         /* I - Size of buffer */
 698 {
 699   const char    *start;                         /* Start of scheme data */
 700   char          *sptr = scheme,                 /* Pointer into scheme buffer */
 701                 *send = scheme + schemesize - 1;/* End of scheme buffer */
 702   int           param;                          /* Is this a parameter? */
 703
 704
 705   DEBUG_printf(("8cups_auth_scheme(www_authenticate=\"%s\", scheme=%p, schemesize=%d)", www_authenticate, (void *)scheme, (int)schemesize));
 706
 707   while (*www_authenticate)
 708   {
 709    /*
 710     * Skip leading whitespace and commas...
 711     */
 712
 713     while (isspace(*www_authenticate & 255) || *www_authenticate == ',')
 714       www_authenticate ++;
 715
 716    /*
 717     * Parse the scheme name or param="value" string...
 718     */
 719
 720     for (sptr = scheme, start = www_authenticate, param = 0; *www_authenticate && *www_authenticate != ',' && !isspace(*www_authenticate & 255); www_authenticate ++)
 721     {
 722       if (*www_authenticate == '=')
 723         param = 1;
 724       else if (!param && sptr < send)
 725         *sptr++ = *www_authenticate;
 726       else if (*www_authenticate == '\"')
 727       {
 728        /*
 729         * Skip quoted value...
 730         */
 731
 732         www_authenticate ++;
 733         while (*www_authenticate && *www_authenticate != '\"')
 734           www_authenticate ++;
 735       }
 736     }
 737
 738     if (sptr > scheme && !param)
 739     {
 740       *sptr = '\0';
 741
 742       DEBUG_printf(("9cups_auth_scheme: Returning \"%s\".", start));
 743
 744       return (start);
 745     }
 746   }
 747
 748   *scheme = '\0';
 749
 750   DEBUG_puts("9cups_auth_scheme: Returning NULL.");
 751
 752   return (NULL);
 753 }
 754
 755
 756 #ifdef HAVE_GSSAPI
 757 #  ifdef HAVE_GSS_ACQUIRE_CRED_EX_F
 758 /*
 759  * 'cups_gss_acquire()' - Kerberos credentials callback.
 760  */
 761 static void
 762 cups_gss_acquire(
 763     void            *ctx,               /* I - Caller context */
 764     OM_uint32       major,              /* I - Major error code */
 765     gss_status_id_t status,             /* I - Status (unused) */
 766     gss_cred_id_t   creds,              /* I - Credentials (if any) */
 767     gss_OID_set     oids,               /* I - Mechanism OIDs (unused) */
 768     OM_uint32       time_rec)           /* I - Timestamp (unused) */
 769 {
 770   uint32_t              min;            /* Minor error code */
 771   _cups_gss_acquire_t   *data;          /* Callback data */
 772
 773
 774   (void)status;
 775   (void)time_rec;
 776
 777   data        = (_cups_gss_acquire_t *)ctx;
 778   data->major = major;
 779   data->creds = creds;
 780
 781   gss_release_oid_set(&min, &oids);
 782   dispatch_semaphore_signal(data->sem);
 783 }
 784 #  endif /* HAVE_GSS_ACQUIRE_CRED_EX_F */
 785
 786
 787 /*
 788  * 'cups_gss_getname()' - Get CUPS service credentials for authentication.
 789  */
 790
 791 static gss_name_t                       /* O - Server name */
 792 cups_gss_getname(
 793     http_t     *http,                   /* I - Connection to server */
 794     const char *service_name)           /* I - Service name */
 795 {
 796   gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
 797                                         /* Service token */
 798   OM_uint32       major_status,         /* Major status code */
 799                   minor_status;         /* Minor status code */
 800   gss_name_t      server_name;          /* Server name */
 801   char            buf[1024];            /* Name buffer */
 802
 803
 804   DEBUG_printf(("7cups_gss_getname(http=%p, service_name=\"%s\")", http,
 805                 service_name));
 806
 807
 808  /*
 809   * Get the hostname...
 810   */
 811
 812   if (!http->gsshost[0])
 813   {
 814     httpGetHostname(http, http->gsshost, sizeof(http->gsshost));
 815
 816     if (!strcmp(http->gsshost, "localhost"))
 817     {
 818       if (gethostname(http->gsshost, sizeof(http->gsshost)) < 0)
 819       {
 820         DEBUG_printf(("1cups_gss_getname: gethostname() failed: %s",
 821                       strerror(errno)));
 822         http->gsshost[0] = '\0';
 823         return (NULL);
 824       }
 825
 826       if (!strchr(http->gsshost, '.'))
 827       {
 828        /*
 829         * The hostname is not a FQDN, so look it up...
 830         */
 831
 832         struct hostent  *host;          /* Host entry to get FQDN */
 833
 834         if ((host = gethostbyname(http->gsshost)) != NULL && host->h_name)
 835         {
 836          /*
 837           * Use the resolved hostname...
 838           */
 839
 840           strlcpy(http->gsshost, host->h_name, sizeof(http->gsshost));
 841         }
 842         else
 843         {
 844           DEBUG_printf(("1cups_gss_getname: gethostbyname(\"%s\") failed.",
 845                         http->gsshost));
 846           http->gsshost[0] = '\0';
 847           return (NULL);
 848         }
 849       }
 850     }
 851   }
 852
 853  /*
 854   * Get a service name we can use for authentication purposes...
 855   */
 856
 857   snprintf(buf, sizeof(buf), "%s@%s", service_name, http->gsshost);
 858
 859   DEBUG_printf(("8cups_gss_getname: Looking up \"%s\".", buf));
 860
 861   token.value  = buf;
 862   token.length = strlen(buf);
 863   server_name  = GSS_C_NO_NAME;
 864   major_status = gss_import_name(&minor_status, &token,
 865                                  GSS_C_NT_HOSTBASED_SERVICE,
 866                                  &server_name);
 867
 868   if (GSS_ERROR(major_status))
 869   {
 870     cups_gss_printf(major_status, minor_status,
 871                     "cups_gss_getname: gss_import_name() failed");
 872     return (NULL);
 873   }
 874
 875   return (server_name);
 876 }
 877
 878
 879 #  ifdef DEBUG
 880 /*
 881  * 'cups_gss_printf()' - Show debug error messages from GSSAPI.
 882  */
 883
 884 static void
 885 cups_gss_printf(OM_uint32  major_status,/* I - Major status code */
 886                 OM_uint32  minor_status,/* I - Minor status code */
 887                 const char *message)    /* I - Prefix for error message */
 888 {
 889   OM_uint32     err_major_status,       /* Major status code for display */
 890                 err_minor_status;       /* Minor status code for display */
 891   OM_uint32     msg_ctx;                /* Message context */
 892   gss_buffer_desc major_status_string = GSS_C_EMPTY_BUFFER,
 893                                         /* Major status message */
 894                 minor_status_string = GSS_C_EMPTY_BUFFER;
 895                                         /* Minor status message */
 896
 897
 898   msg_ctx          = 0;
 899   err_major_status = gss_display_status(&err_minor_status,
 900                                         major_status,
 901                                         GSS_C_GSS_CODE,
 902                                         GSS_C_NO_OID,
 903                                         &msg_ctx,
 904                                         &major_status_string);
 905
 906   if (!GSS_ERROR(err_major_status))
 907     gss_display_status(&err_minor_status, minor_status, GSS_C_MECH_CODE,
 908                        GSS_C_NULL_OID, &msg_ctx, &minor_status_string);
 909
 910   DEBUG_printf(("1%s: %s, %s", message, (char *)major_status_string.value,
 911                 (char *)minor_status_string.value));
 912
 913   gss_release_buffer(&err_minor_status, &major_status_string);
 914   gss_release_buffer(&err_minor_status, &minor_status_string);
 915 }
 916 #  endif /* DEBUG */
 917 #endif /* HAVE_GSSAPI */
 918
 919
 920 /*
 921  * 'cups_local_auth()' - Get the local authorization certificate if
 922  *                       available/applicable.
 923  */
 924
 925 static int                              /* O - 0 if available */
 926                                         /*     1 if not available */
 927                                         /*    -1 error */
 928 cups_local_auth(http_t *http)           /* I - HTTP connection to server */
 929 {
 930 #if defined(_WIN32) || defined(__EMX__)
 931  /*
 932   * Currently _WIN32 and OS-2 do not support the CUPS server...
 933   */
 934
 935   return (1);
 936 #else
 937   int                   pid;            /* Current process ID */
 938   FILE                  *fp;            /* Certificate file */
 939   char                  trc[16],        /* Try Root Certificate parameter */
 940                         filename[1024]; /* Certificate filename */
 941   const char            *www_auth,      /* WWW-Authenticate header */
 942                         *schemedata;    /* Data for the named auth scheme */
 943   _cups_globals_t *cg = _cupsGlobals(); /* Global data */
 944 #  if defined(HAVE_AUTHORIZATION_H)
 945   OSStatus              status;         /* Status */
 946   AuthorizationItem     auth_right;     /* Authorization right */
 947   AuthorizationRights   auth_rights;    /* Authorization rights */
 948   AuthorizationFlags    auth_flags;     /* Authorization flags */
 949   AuthorizationExternalForm auth_extrn; /* Authorization ref external */
 950   char                  auth_key[1024]; /* Buffer */
 951   char                  buffer[1024];   /* Buffer */
 952 #  endif /* HAVE_AUTHORIZATION_H */
 953
 954
 955   DEBUG_printf(("7cups_local_auth(http=%p) hostaddr=%s, hostname=\"%s\"", (void *)http, httpAddrString(http->hostaddr, filename, sizeof(filename)), http->hostname));
 956
 957  /*
 958   * See if we are accessing localhost...
 959   */
 960
 961   if (!httpAddrLocalhost(http->hostaddr) && _cups_strcasecmp(http->hostname, "localhost") != 0)
 962   {
 963     DEBUG_puts("8cups_local_auth: Not a local connection!");
 964     return (1);
 965   }
 966
 967   www_auth = httpGetField(http, HTTP_FIELD_WWW_AUTHENTICATE);
 968
 969 #  if defined(HAVE_AUTHORIZATION_H)
 970  /*
 971   * Delete any previous authorization reference...
 972   */
 973
 974   if (http->auth_ref)
 975   {
 976     AuthorizationFree(http->auth_ref, kAuthorizationFlagDefaults);
 977     http->auth_ref = NULL;
 978   }
 979
 980   if (!getenv("GATEWAY_INTERFACE") && (schemedata = cups_auth_find(www_auth, "AuthRef")) != NULL && cups_auth_param(schemedata, "key", auth_key, sizeof(auth_key)))
 981   {
 982     status = AuthorizationCreate(NULL, kAuthorizationEmptyEnvironment, kAuthorizationFlagDefaults, &http->auth_ref);
 983     if (status != errAuthorizationSuccess)
 984     {
 985       DEBUG_printf(("8cups_local_auth: AuthorizationCreate() returned %d",
 986                     (int)status));
 987       return (-1);
 988     }
 989
 990     auth_right.name        = auth_key;
 991     auth_right.valueLength = 0;
 992     auth_right.value       = NULL;
 993     auth_right.flags       = 0;
 994
 995     auth_rights.count = 1;
 996     auth_rights.items = &auth_right;
 997
 998     auth_flags = kAuthorizationFlagDefaults |
 999                  kAuthorizationFlagPreAuthorize |
1000                  kAuthorizationFlagInteractionAllowed |
1001                  kAuthorizationFlagExtendRights;
1002
1003     status = AuthorizationCopyRights(http->auth_ref, &auth_rights,
1004                                      kAuthorizationEmptyEnvironment,
1005                                      auth_flags, NULL);
1006     if (status == errAuthorizationSuccess)
1007       status = AuthorizationMakeExternalForm(http->auth_ref, &auth_extrn);
1008
1009     if (status == errAuthorizationSuccess)
1010     {
1011      /*
1012       * Set the authorization string and return...
1013       */
1014
1015       httpEncode64_2(buffer, sizeof(buffer), (void *)&auth_extrn,
1016                      sizeof(auth_extrn));
1017
1018       httpSetAuthString(http, "AuthRef", buffer);
1019
1020       DEBUG_printf(("8cups_local_auth: Returning authstring=\"%s\"",
1021                     http->authstring));
1022       return (0);
1023     }
1024     else if (status == errAuthorizationCanceled)
1025       return (-1);
1026
1027     DEBUG_printf(("9cups_local_auth: AuthorizationCopyRights() returned %d", (int)status));
1028
1029   /*
1030    * Fall through to try certificates...
1031    */
1032   }
1033 #  endif /* HAVE_AUTHORIZATION_H */
1034
1035 #  ifdef HAVE_GSSAPI
1036   if (cups_auth_find(www_auth, "Negotiate"))
1037     return (1);
1038 #  endif /* HAVE_GSSAPI */
1039
1040 #  if defined(SO_PEERCRED) && defined(AF_LOCAL)
1041  /*
1042   * See if we can authenticate using the peer credentials provided over a
1043   * domain socket; if so, specify "PeerCred username" as the authentication
1044   * information...
1045   */
1046
1047   if (http->hostaddr->addr.sa_family == AF_LOCAL &&
1048       !getenv("GATEWAY_INTERFACE") &&   /* Not via CGI programs... */
1049       cups_auth_find(www_auth, "PeerCred"))
1050   {
1051    /*
1052     * Verify that the current cupsUser() matches the current UID...
1053     */
1054
1055     struct passwd       *pwd;           /* Password information */
1056     const char          *username;      /* Current username */
1057
1058     username = cupsUser();
1059
1060     if ((pwd = getpwnam(username)) != NULL && pwd->pw_uid == getuid())
1061     {
1062       httpSetAuthString(http, "PeerCred", username);
1063
1064       DEBUG_printf(("8cups_local_auth: Returning authstring=\"%s\"",
1065                     http->authstring));
1066
1067       return (0);
1068     }
1069   }
1070 #  endif /* SO_PEERCRED && AF_LOCAL */
1071
1072   if ((schemedata = cups_auth_find(www_auth, "Local")) == NULL)
1073     return (1);
1074
1075  /*
1076   * Try opening a certificate file for this PID.  If that fails,
1077   * try the root certificate...
1078   */
1079
1080   pid = getpid();
1081   snprintf(filename, sizeof(filename), "%s/certs/%d", cg->cups_statedir, pid);
1082   if ((fp = fopen(filename, "r")) == NULL && pid > 0)
1083   {
1084    /*
1085     * No certificate for this PID; see if we can get the root certificate...
1086     */
1087
1088     DEBUG_printf(("9cups_local_auth: Unable to open file \"%s\": %s", filename, strerror(errno)));
1089
1090     if (!cups_auth_param(schemedata, "trc", trc, sizeof(trc)))
1091     {
1092      /*
1093       * Scheduler doesn't want us to use the root certificate...
1094       */
1095
1096       return (1);
1097     }
1098
1099     snprintf(filename, sizeof(filename), "%s/certs/0", cg->cups_statedir);
1100     if ((fp = fopen(filename, "r")) == NULL)
1101       DEBUG_printf(("9cups_local_auth: Unable to open file \"%s\": %s", filename, strerror(errno)));
1102   }
1103
1104   if (fp)
1105   {
1106    /*
1107     * Read the certificate from the file...
1108     */
1109
1110     char        certificate[33],        /* Certificate string */
1111                 *certptr;               /* Pointer to certificate string */
1112
1113     certptr = fgets(certificate, sizeof(certificate), fp);
1114     fclose(fp);
1115
1116     if (certptr)
1117     {
1118      /*
1119       * Set the authorization string and return...
1120       */
1121
1122       httpSetAuthString(http, "Local", certificate);
1123
1124       DEBUG_printf(("8cups_local_auth: Returning authstring=\"%s\"",
1125                     http->authstring));
1126
1127       return (0);
1128     }
1129   }
1130
1131   return (1);
1132 #endif /* _WIN32 || __EMX__ */
1133 }