src/auth/digest/auth_digest.cc

   1 /*
   2  * $Id$
   3  *
   4  * DEBUG: section 29    Authenticator
   5  * AUTHOR: Robert Collins
   6  *
   7  * SQUID Internet Object Cache  http://squid.nlanr.net/Squid/
   8  * ----------------------------------------------------------
   9  *
  10  *  Squid is the result of efforts by numerous individuals from the
  11  *  Internet community.  Development is led by Duane Wessels of the
  12  *  National Laboratory for Applied Network Research and funded by the
  13  *  National Science Foundation.  Squid is Copyrighted (C) 1998 by
  14  *  the Regents of the University of California.  Please see the
  15  *  COPYRIGHT file for full details.  Squid incorporates software
  16  *  developed and/or copyrighted by other sources.  Please see the
  17  *  CREDITS file for full details.
  18  *
  19  *  This program is free software; you can redistribute it and/or modify
  20  *  it under the terms of the GNU General Public License as published by
  21  *  the Free Software Foundation; either version 2 of the License, or
  22  *  (at your option) any later version.
  23  *
  24  *  This program is distributed in the hope that it will be useful,
  25  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  26  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  27  *  GNU General Public License for more details.
  28  *
  29  *  You should have received a copy of the GNU General Public License
  30  *  along with this program; if not, write to the Free Software
  31  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  32  *
  33  */
  34
  35 /* The functions in this file handle authentication.
  36  * They DO NOT perform access control or auditing.
  37  * See acl.c for access control and client_side.c for auditing */
  38
  39
  40 #include "squid.h"
  41 #include "rfc2617.h"
  42 #include "auth/digest/auth_digest.h"
  43 #include "auth/Gadgets.h"
  44 #include "event.h"
  45 #include "CacheManager.h"
  46 #include "Store.h"
  47 #include "HttpRequest.h"
  48 #include "HttpReply.h"
  49 #include "wordlist.h"
  50 #include "SquidTime.h"
  51 /* TODO don't include this */
  52 #include "auth/digest/digestScheme.h"
  53 #include "auth/digest/digestUserRequest.h"
  54
  55 /* Digest Scheme */
  56
  57 static AUTHSSTATS authenticateDigestStats;
  58
  59 helper *digestauthenticators = NULL;
  60
  61 static hash_table *digest_nonce_cache;
  62
  63 static int authdigest_initialised = 0;
  64 static MemAllocator *digest_nonce_pool = NULL;
  65
  66 // CBDATA_TYPE(DigestAuthenticateStateData);
  67
  68 enum http_digest_attr_type {
  69     DIGEST_USERNAME,
  70     DIGEST_REALM,
  71     DIGEST_QOP,
  72     DIGEST_ALGORITHM,
  73     DIGEST_URI,
  74     DIGEST_NONCE,
  75     DIGEST_NC,
  76     DIGEST_CNONCE,
  77     DIGEST_RESPONSE,
  78     DIGEST_ENUM_END
  79 };
  80
  81 static const HttpHeaderFieldAttrs DigestAttrs[DIGEST_ENUM_END] = {
  82     {"username",  (http_hdr_type)DIGEST_USERNAME},
  83     {"realm", (http_hdr_type)DIGEST_REALM},
  84     {"qop", (http_hdr_type)DIGEST_QOP},
  85     {"algorithm", (http_hdr_type)DIGEST_ALGORITHM},
  86     {"uri", (http_hdr_type)DIGEST_URI},
  87     {"nonce", (http_hdr_type)DIGEST_NONCE},
  88     {"nc", (http_hdr_type)DIGEST_NC},
  89     {"cnonce", (http_hdr_type)DIGEST_CNONCE},
  90     {"response", (http_hdr_type)DIGEST_RESPONSE},
  91 };
  92
  93 static HttpHeaderFieldInfo *DigestFieldsInfo = NULL;
  94
  95 /*
  96  *
  97  * Nonce Functions
  98  *
  99  */
 100
 101 static void authenticateDigestNonceCacheCleanup(void *data);
 102 static digest_nonce_h *authenticateDigestNonceFindNonce(const char *nonceb64);
 103 static digest_nonce_h *authenticateDigestNonceNew(void);
 104 static void authenticateDigestNonceDelete(digest_nonce_h * nonce);
 105 static void authenticateDigestNonceSetup(void);
 106 static void authenticateDigestNonceShutdown(void);
 107 static void authenticateDigestNonceReconfigure(void);
 108 static int authDigestNonceIsStale(digest_nonce_h * nonce);
 109 static void authDigestNonceEncode(digest_nonce_h * nonce);
 110 static void authDigestNonceLink(digest_nonce_h * nonce);
 111 #if NOT_USED
 112 static int authDigestNonceLinks(digest_nonce_h * nonce);
 113 #endif
 114 static void authDigestNonceUserUnlink(digest_nonce_h * nonce);
 115 static void authDigestNoncePurge(digest_nonce_h * nonce);
 116
 117 static void
 118 authDigestNonceEncode(digest_nonce_h * nonce)
 119 {
 120     if (!nonce)
 121         return;
 122
 123     if (nonce->key)
 124         xfree(nonce->key);
 125
 126     nonce->key = xstrdup(base64_encode_bin((char *) &(nonce->noncedata), sizeof(digest_nonce_data)));
 127 }
 128
 129 static digest_nonce_h *
 130 authenticateDigestNonceNew(void)
 131 {
 132     digest_nonce_h *newnonce = static_cast < digest_nonce_h * >(digest_nonce_pool->alloc());
 133     digest_nonce_h *temp;
 134
 135     /* NONCE CREATION - NOTES AND REASONING. RBC 20010108
 136      * === EXCERPT FROM RFC 2617 ===
 137      * The contents of the nonce are implementation dependent. The quality
 138      * of the implementation depends on a good choice. A nonce might, for
 139      * example, be constructed as the base 64 encoding of
 140      *
 141      * time-stamp H(time-stamp ":" ETag ":" private-key)
 142      *
 143      * where time-stamp is a server-generated time or other non-repeating
 144      * value, ETag is the value of the HTTP ETag header associated with
 145      * the requested entity, and private-key is data known only to the
 146      * server.  With a nonce of this form a server would recalculate the
 147      * hash portion after receiving the client authentication header and
 148      * reject the request if it did not match the nonce from that header
 149      * or if the time-stamp value is not recent enough. In this way the
 150      * server can limit the time of the nonce's validity. The inclusion of
 151      * the ETag prevents a replay request for an updated version of the
 152      * resource.  (Note: including the IP address of the client in the
 153      * nonce would appear to offer the server the ability to limit the
 154      * reuse of the nonce to the same client that originally got it.
 155      * However, that would break proxy farms, where requests from a single
 156      * user often go through different proxies in the farm. Also, IP
 157      * address spoofing is not that hard.)
 158      * ====
 159      *
 160      * Now for my reasoning:
 161      * We will not accept a unrecognised nonce->we have all recognisable
 162      * nonces stored. If we send out unique base64 encodings we guarantee
 163      * that a given nonce applies to only one user (barring attacks or
 164      * really bad timing with expiry and creation).  Using a random
 165      * component in the nonce allows us to loop to find a unique nonce.
 166      * We use H(nonce_data) so the nonce is meaningless to the reciever.
 167      * So our nonce looks like base64(H(timestamp,pointertohash,randomdata))
 168      * And even if our randomness is not very random (probably due to
 169      * bad coding on my part) we don't really care - the timestamp and
 170      * memory pointer also guarantee local uniqueness in the input to the hash
 171      * function.
 172      */
 173
 174     /* create a new nonce */
 175     newnonce->nc = 0;
 176     newnonce->flags.valid = 1;
 177     newnonce->noncedata.self = newnonce;
 178     newnonce->noncedata.creationtime = current_time.tv_sec;
 179     newnonce->noncedata.randomdata = squid_random();
 180
 181     authDigestNonceEncode(newnonce);
 182     /*
 183      * loop until we get a unique nonce. The nonce creation must
 184      * have a random factor
 185      */
 186
 187     while ((temp = authenticateDigestNonceFindNonce((char const *) (newnonce->key)))) {
 188         /* create a new nonce */
 189         newnonce->noncedata.randomdata = squid_random();
 190         authDigestNonceEncode(newnonce);
 191     }
 192
 193     hash_join(digest_nonce_cache, newnonce);
 194     /* the cache's link */
 195     authDigestNonceLink(newnonce);
 196     newnonce->flags.incache = 1;
 197     debugs(29, 5, "authenticateDigestNonceNew: created nonce " << newnonce << " at " << newnonce->noncedata.creationtime);
 198     return newnonce;
 199 }
 200
 201 static void
 202 authenticateDigestNonceDelete(digest_nonce_h * nonce)
 203 {
 204     if (nonce) {
 205         assert(nonce->references == 0);
 206 #if UNREACHABLECODE
 207
 208         if (nonce->flags.incache)
 209             hash_remove_link(digest_nonce_cache, nonce);
 210
 211 #endif
 212
 213         assert(nonce->flags.incache == 0);
 214
 215         safe_free(nonce->key);
 216
 217         digest_nonce_pool->free(nonce);
 218     }
 219 }
 220
 221 static void
 222 authenticateDigestNonceSetup(void)
 223 {
 224     if (!digest_nonce_pool)
 225         digest_nonce_pool = memPoolCreate("Digest Scheme nonce's", sizeof(digest_nonce_h));
 226
 227     if (!digest_nonce_cache) {
 228         digest_nonce_cache = hash_create((HASHCMP *) strcmp, 7921, hash_string);
 229         assert(digest_nonce_cache);
 230         eventAdd("Digest none cache maintenance", authenticateDigestNonceCacheCleanup, NULL, static_cast<AuthDigestConfig*>(AuthConfig::Find("digest"))->nonceGCInterval, 1);
 231     }
 232 }
 233
 234 static void
 235 authenticateDigestNonceShutdown(void)
 236 {
 237     /*
 238      * We empty the cache of any nonces left in there.
 239      */
 240     digest_nonce_h *nonce;
 241
 242     if (digest_nonce_cache) {
 243         debugs(29, 2, "authenticateDigestNonceShutdown: Shutting down nonce cache ");
 244         hash_first(digest_nonce_cache);
 245
 246         while ((nonce = ((digest_nonce_h *) hash_next(digest_nonce_cache)))) {
 247             assert(nonce->flags.incache);
 248             authDigestNoncePurge(nonce);
 249         }
 250     }
 251
 252 #if DEBUGSHUTDOWN
 253     if (digest_nonce_pool) {
 254         delete digest_nonce_pool;
 255         digest_nonce_pool = NULL;
 256     }
 257
 258 #endif
 259     debugs(29, 2, "authenticateDigestNonceShutdown: Nonce cache shutdown");
 260 }
 261
 262 static void
 263 authenticateDigestNonceReconfigure(void)
 264 {}
 265
 266 static void
 267 authenticateDigestNonceCacheCleanup(void *data)
 268 {
 269     /*
 270      * We walk the hash by nonceb64 as that is the unique key we
 271      * use.  For big hash tables we could consider stepping through
 272      * the cache, 100/200 entries at a time. Lets see how it flies
 273      * first.
 274      */
 275     digest_nonce_h *nonce;
 276     debugs(29, 3, "authenticateDigestNonceCacheCleanup: Cleaning the nonce cache now");
 277     debugs(29, 3, "authenticateDigestNonceCacheCleanup: Current time: " << current_time.tv_sec);
 278     hash_first(digest_nonce_cache);
 279
 280     while ((nonce = ((digest_nonce_h *) hash_next(digest_nonce_cache)))) {
 281         debugs(29, 3, "authenticateDigestNonceCacheCleanup: nonce entry  : " << nonce << " '" << (char *) nonce->key << "'");
 282         debugs(29, 4, "authenticateDigestNonceCacheCleanup: Creation time: " << nonce->noncedata.creationtime);
 283
 284         if (authDigestNonceIsStale(nonce)) {
 285             debugs(29, 4, "authenticateDigestNonceCacheCleanup: Removing nonce " << (char *) nonce->key << " from cache due to timeout.");
 286             assert(nonce->flags.incache);
 287             /* invalidate nonce so future requests fail */
 288             nonce->flags.valid = 0;
 289             /* if it is tied to a auth_user, remove the tie */
 290             authDigestNonceUserUnlink(nonce);
 291             authDigestNoncePurge(nonce);
 292         }
 293     }
 294
 295     debugs(29, 3, "authenticateDigestNonceCacheCleanup: Finished cleaning the nonce cache.");
 296
 297     if (static_cast<AuthDigestConfig*>(AuthConfig::Find("digest"))->active())
 298         eventAdd("Digest none cache maintenance", authenticateDigestNonceCacheCleanup, NULL, static_cast<AuthDigestConfig*>(AuthConfig::Find("digest"))->nonceGCInterval, 1);
 299 }
 300
 301 static void
 302 authDigestNonceLink(digest_nonce_h * nonce)
 303 {
 304     assert(nonce != NULL);
 305     nonce->references++;
 306     debugs(29, 9, "authDigestNonceLink: nonce '" << nonce << "' now at '" << nonce->references << "'.");
 307 }
 308
 309 #if NOT_USED
 310 static int
 311 authDigestNonceLinks(digest_nonce_h * nonce)
 312 {
 313     if (!nonce)
 314         return -1;
 315
 316     return nonce->references;
 317 }
 318
 319 #endif
 320
 321 void
 322 authDigestNonceUnlink(digest_nonce_h * nonce)
 323 {
 324     assert(nonce != NULL);
 325
 326     if (nonce->references > 0) {
 327         nonce->references--;
 328     } else {
 329         debugs(29, 1, "authDigestNonceUnlink; Attempt to lower nonce " << nonce << " refcount below 0!");
 330     }
 331
 332     debugs(29, 9, "authDigestNonceUnlink: nonce '" << nonce << "' now at '" << nonce->references << "'.");
 333
 334     if (nonce->references == 0)
 335         authenticateDigestNonceDelete(nonce);
 336 }
 337
 338 const char *
 339 authenticateDigestNonceNonceb64(const digest_nonce_h * nonce)
 340 {
 341     if (!nonce)
 342         return NULL;
 343
 344     return (char const *) nonce->key;
 345 }
 346
 347 static digest_nonce_h *
 348 authenticateDigestNonceFindNonce(const char *nonceb64)
 349 {
 350     digest_nonce_h *nonce = NULL;
 351
 352     if (nonceb64 == NULL)
 353         return NULL;
 354
 355     debugs(29, 9, "authDigestNonceFindNonce:looking for nonceb64 '" << nonceb64 << "' in the nonce cache.");
 356
 357     nonce = static_cast < digest_nonce_h * >(hash_lookup(digest_nonce_cache, nonceb64));
 358
 359     if ((nonce == NULL) || (strcmp(authenticateDigestNonceNonceb64(nonce), nonceb64)))
 360         return NULL;
 361
 362     debugs(29, 9, "authDigestNonceFindNonce: Found nonce '" << nonce << "'");
 363
 364     return nonce;
 365 }
 366
 367 int
 368 authDigestNonceIsValid(digest_nonce_h * nonce, char nc[9])
 369 {
 370     unsigned long intnc;
 371     /* do we have a nonce ? */
 372
 373     if (!nonce)
 374         return 0;
 375
 376     intnc = strtol(nc, NULL, 16);
 377
 378     /* has it already been invalidated ? */
 379     if (!nonce->flags.valid) {
 380         debugs(29, 4, "authDigestNonceIsValid: Nonce already invalidated");
 381         return 0;
 382     }
 383
 384     /* is the nonce-count ok ? */
 385     if (!static_cast<AuthDigestConfig*>(AuthConfig::Find("digest"))->CheckNonceCount) {
 386         nonce->nc++;
 387         return -1;              /* forced OK by configuration */
 388     }
 389
 390     if ((static_cast<AuthDigestConfig*>(AuthConfig::Find("digest"))->NonceStrictness && intnc != nonce->nc + 1) ||
 391             intnc < nonce->nc + 1) {
 392         debugs(29, 4, "authDigestNonceIsValid: Nonce count doesn't match");
 393         nonce->flags.valid = 0;
 394         return 0;
 395     }
 396
 397     /* seems ok */
 398     /* increment the nonce count - we've already checked that intnc is a
 399      *  valid representation for us, so we don't need the test here.
 400      */
 401     nonce->nc = intnc;
 402
 403     return -1;
 404 }
 405
 406 static int
 407 authDigestNonceIsStale(digest_nonce_h * nonce)
 408 {
 409     /* do we have a nonce ? */
 410
 411     if (!nonce)
 412         return -1;
 413
 414     /* has it's max duration expired? */
 415     if (nonce->noncedata.creationtime + static_cast<AuthDigestConfig*>(AuthConfig::Find("digest"))->noncemaxduration < current_time.tv_sec) {
 416         debugs(29, 4, "authDigestNonceIsStale: Nonce is too old. " <<
 417                nonce->noncedata.creationtime << " " <<
 418                static_cast<AuthDigestConfig*>(AuthConfig::Find("digest"))->noncemaxduration << " " <<
 419                current_time.tv_sec);
 420
 421         nonce->flags.valid = 0;
 422         return -1;
 423     }
 424
 425     if (nonce->nc > 99999998) {
 426         debugs(29, 4, "authDigestNonceIsStale: Nonce count overflow");
 427         nonce->flags.valid = 0;
 428         return -1;
 429     }
 430
 431     if (nonce->nc > static_cast<AuthDigestConfig*>(AuthConfig::Find("digest"))->noncemaxuses) {
 432         debugs(29, 4, "authDigestNoncelastRequest: Nonce count over user limit");
 433         nonce->flags.valid = 0;
 434         return -1;
 435     }
 436
 437     /* seems ok */
 438     return 0;
 439 }
 440
 441 /**
 442  * \retval  0    the digest is not stale yet
 443  * \retval -1    the digest will be stale on the next request
 444  */
 445 const int
 446 authDigestNonceLastRequest(digest_nonce_h * nonce)
 447 {
 448     if (!nonce)
 449         return -1;
 450
 451     if (nonce->nc == 99999997) {
 452         debugs(29, 4, "authDigestNoncelastRequest: Nonce count about to overflow");
 453         return -1;
 454     }
 455
 456     if (nonce->nc >= static_cast<AuthDigestConfig*>(AuthConfig::Find("digest"))->noncemaxuses - 1) {
 457         debugs(29, 4, "authDigestNoncelastRequest: Nonce count about to hit user limit");
 458         return -1;
 459     }
 460
 461     /* and other tests are possible. */
 462     return 0;
 463 }
 464
 465 static void
 466 authDigestNoncePurge(digest_nonce_h * nonce)
 467 {
 468     if (!nonce)
 469         return;
 470
 471     if (!nonce->flags.incache)
 472         return;
 473
 474     hash_remove_link(digest_nonce_cache, nonce);
 475
 476     nonce->flags.incache = 0;
 477
 478     /* the cache's link */
 479     authDigestNonceUnlink(nonce);
 480 }
 481
 482 /* USER related functions */
 483 static AuthUser *
 484 authDigestUserFindUsername(const char *username)
 485 {
 486     AuthUserHashPointer *usernamehash;
 487     AuthUser *auth_user;
 488     debugs(29, 9, HERE << "Looking for user '" << username << "'");
 489
 490     if (username && (usernamehash = static_cast < auth_user_hash_pointer * >(hash_lookup(proxy_auth_username_cache, username)))) {
 491         while ((usernamehash->user()->auth_type != AUTH_DIGEST) &&
 492                 (usernamehash->next))
 493             usernamehash = static_cast < auth_user_hash_pointer * >(usernamehash->next);
 494
 495         auth_user = NULL;
 496
 497         if (usernamehash->user()->auth_type == AUTH_DIGEST) {
 498             auth_user = usernamehash->user();
 499         }
 500
 501         return auth_user;
 502     }
 503
 504     return NULL;
 505 }
 506
 507 static void
 508 authDigestUserShutdown(void)
 509 {
 510     /** \todo Future work: the auth framework could flush it's cache */
 511     AuthUserHashPointer *usernamehash;
 512     AuthUser *auth_user;
 513     hash_first(proxy_auth_username_cache);
 514
 515     while ((usernamehash = ((auth_user_hash_pointer *) hash_next(proxy_auth_username_cache)))) {
 516         auth_user = usernamehash->user();
 517
 518         if (strcmp(auth_user->config->type(), "digest") == 0)
 519             auth_user->unlock();
 520     }
 521 }
 522
 523 /** delete the digest request structure. Does NOT delete related structures */
 524 void
 525 digestScheme::done()
 526 {
 527     /** \todo this should be a Config call. */
 528
 529     if (digestauthenticators)
 530         helperShutdown(digestauthenticators);
 531
 532     httpHeaderDestroyFieldsInfo(DigestFieldsInfo, DIGEST_ENUM_END);
 533     DigestFieldsInfo = NULL;
 534
 535     authdigest_initialised = 0;
 536
 537     if (!shutting_down) {
 538         authenticateDigestNonceReconfigure();
 539         return;
 540     }
 541
 542     delete digestauthenticators;
 543     digestauthenticators = NULL;
 544
 545     authDigestUserShutdown();
 546     authenticateDigestNonceShutdown();
 547     debugs(29, 2, "authenticateDigestDone: Digest authentication shut down.");
 548
 549     /* clear the global handle to this scheme. */
 550     _instance = NULL;
 551 }
 552
 553 void
 554 AuthDigestConfig::dump(StoreEntry * entry, const char *name, AuthConfig * scheme)
 555 {
 556     wordlist *list = authenticate;
 557     debugs(29, 9, "authDigestCfgDump: Dumping configuration");
 558     storeAppendPrintf(entry, "%s %s", name, "digest");
 559
 560     while (list != NULL) {
 561         storeAppendPrintf(entry, " %s", list->key);
 562         list = list->next;
 563     }
 564
 565     storeAppendPrintf(entry, "\n%s %s realm %s\n%s %s children %d startup=%d idle=%d concurrency=%d\n%s %s nonce_max_count %d\n%s %s nonce_max_duration %d seconds\n%s %s nonce_garbage_interval %d seconds\n",
 566                       name, "digest", digestAuthRealm,
 567                       name, "digest", authenticateChildren.n_max, authenticateChildren.n_startup, authenticateChildren.n_idle, authenticateChildren.concurrency,
 568                       name, "digest", noncemaxuses,
 569                       name, "digest", (int) noncemaxduration,
 570                       name, "digest", (int) nonceGCInterval);
 571 }
 572
 573 bool
 574 AuthDigestConfig::active() const
 575 {
 576     return authdigest_initialised == 1;
 577 }
 578
 579 bool
 580 AuthDigestConfig::configured() const
 581 {
 582     if ((authenticate != NULL) &&
 583             (authenticateChildren.n_max != 0) &&
 584             (digestAuthRealm != NULL) && (noncemaxduration > -1))
 585         return true;
 586
 587     return false;
 588 }
 589
 590 /* add the [www-|Proxy-]authenticate header on a 407 or 401 reply */
 591 void
 592 AuthDigestConfig::fixHeader(AuthUserRequest::Pointer auth_user_request, HttpReply *rep, http_hdr_type hdrType, HttpRequest * request)
 593 {
 594     if (!authenticate)
 595         return;
 596
 597     int stale = 0;
 598
 599     if (auth_user_request != NULL) {
 600         AuthDigestUserRequest *digest_request;
 601         digest_request = dynamic_cast<AuthDigestUserRequest*>(auth_user_request.getRaw());
 602         assert (digest_request != NULL);
 603
 604         stale = !digest_request->flags.invalid_password;
 605     }
 606
 607     /* on a 407 or 401 we always use a new nonce */
 608     digest_nonce_h *nonce = authenticateDigestNonceNew();
 609
 610     debugs(29, 9, "authenticateFixHeader: Sending type:" << hdrType <<
 611            " header: 'Digest realm=\"" << digestAuthRealm << "\", nonce=\"" <<
 612            authenticateDigestNonceNonceb64(nonce) << "\", qop=\"" << QOP_AUTH <<
 613            "\", stale=" << (stale ? "true" : "false"));
 614
 615     /* in the future, for WWW auth we may want to support the domain entry */
 616     httpHeaderPutStrf(&rep->header, hdrType, "Digest realm=\"%s\", nonce=\"%s\", qop=\"%s\", stale=%s", digestAuthRealm, authenticateDigestNonceNonceb64(nonce), QOP_AUTH, stale ? "true" : "false");
 617 }
 618
 619 DigestUser::~DigestUser()
 620 {
 621
 622     dlink_node *link, *tmplink;
 623     link = nonces.head;
 624
 625     while (link) {
 626         tmplink = link;
 627         link = link->next;
 628         dlinkDelete(tmplink, &nonces);
 629         authDigestNoncePurge(static_cast < digest_nonce_h * >(tmplink->data));
 630         authDigestNonceUnlink(static_cast < digest_nonce_h * >(tmplink->data));
 631         dlinkNodeDelete(tmplink);
 632     }
 633 }
 634
 635 /* Initialize helpers and the like for this auth scheme. Called AFTER parsing the
 636  * config file */
 637 void
 638 AuthDigestConfig::init(AuthConfig * scheme)
 639 {
 640     if (authenticate) {
 641         DigestFieldsInfo = httpHeaderBuildFieldsInfo(DigestAttrs, DIGEST_ENUM_END);
 642         authenticateDigestNonceSetup();
 643         authdigest_initialised = 1;
 644
 645         if (digestauthenticators == NULL)
 646             digestauthenticators = new helper("digestauthenticator");
 647
 648         digestauthenticators->cmdline = authenticate;
 649
 650         digestauthenticators->childs = authenticateChildren;
 651
 652         digestauthenticators->ipc_type = IPC_STREAM;
 653
 654         helperOpenServers(digestauthenticators);
 655
 656         CBDATA_INIT_TYPE(authenticateStateData);
 657     }
 658 }
 659
 660 void
 661 AuthDigestConfig::registerWithCacheManager(void)
 662 {
 663     CacheManager::GetInstance()->
 664     registerAction("digestauthenticator",
 665                    "Digest User Authenticator Stats",
 666                    authenticateDigestStats, 0, 1);
 667 }
 668
 669 /* free any allocated configuration details */
 670 void
 671 AuthDigestConfig::done()
 672 {
 673     if (authenticate)
 674         wordlistDestroy(&authenticate);
 675
 676     safe_free(digestAuthRealm);
 677 }
 678
 679 AuthDigestConfig::AuthDigestConfig()
 680 {
 681     /* TODO: move into initialisation list */
 682     /* 5 minutes */
 683     nonceGCInterval = 5 * 60;
 684     /* 30 minutes */
 685     noncemaxduration = 30 * 60;
 686     /* 50 requests */
 687     noncemaxuses = 50;
 688     /* Not strict nonce count behaviour */
 689     NonceStrictness = 0;
 690     /* Verify nonce count */
 691     CheckNonceCount = 1;
 692 }
 693
 694 void
 695 AuthDigestConfig::parse(AuthConfig * scheme, int n_configured, char *param_str)
 696 {
 697     if (strcasecmp(param_str, "program") == 0) {
 698         if (authenticate)
 699             wordlistDestroy(&authenticate);
 700
 701         parse_wordlist(&authenticate);
 702
 703         requirePathnameExists("auth_param digest program", authenticate->key);
 704     } else if (strcasecmp(param_str, "children") == 0) {
 705         authenticateChildren.parseConfig();
 706     } else if (strcasecmp(param_str, "realm") == 0) {
 707         parse_eol(&digestAuthRealm);
 708     } else if (strcasecmp(param_str, "nonce_garbage_interval") == 0) {
 709         parse_time_t(&nonceGCInterval);
 710     } else if (strcasecmp(param_str, "nonce_max_duration") == 0) {
 711         parse_time_t(&noncemaxduration);
 712     } else if (strcasecmp(param_str, "nonce_max_count") == 0) {
 713         parse_int((int *) &noncemaxuses);
 714     } else if (strcasecmp(param_str, "nonce_strictness") == 0) {
 715         parse_onoff(&NonceStrictness);
 716     } else if (strcasecmp(param_str, "check_nonce_count") == 0) {
 717         parse_onoff(&CheckNonceCount);
 718     } else if (strcasecmp(param_str, "post_workaround") == 0) {
 719         parse_onoff(&PostWorkaround);
 720     } else if (strcasecmp(param_str, "utf8") == 0) {
 721         parse_onoff(&utf8);
 722     } else {
 723         debugs(29, 0, "unrecognised digest auth scheme parameter '" << param_str << "'");
 724     }
 725 }
 726
 727 const char *
 728 AuthDigestConfig::type() const
 729 {
 730     return digestScheme::GetInstance()->type();
 731 }
 732
 733
 734 static void
 735 authenticateDigestStats(StoreEntry * sentry)
 736 {
 737     helperStats(sentry, digestauthenticators, "Digest Authenticator Statistics");
 738 }
 739
 740 /* NonceUserUnlink: remove the reference to auth_user and unlink the node from the list */
 741
 742 static void
 743 authDigestNonceUserUnlink(digest_nonce_h * nonce)
 744 {
 745     digest_user_h *digest_user;
 746     dlink_node *link, *tmplink;
 747
 748     if (!nonce)
 749         return;
 750
 751     if (!nonce->user)
 752         return;
 753
 754     digest_user = nonce->user;
 755
 756     /* unlink from the user list. Yes we're crossing structures but this is the only
 757      * time this code is needed
 758      */
 759     link = digest_user->nonces.head;
 760
 761     while (link) {
 762         tmplink = link;
 763         link = link->next;
 764
 765         if (tmplink->data == nonce) {
 766             dlinkDelete(tmplink, &digest_user->nonces);
 767             authDigestNonceUnlink(static_cast < digest_nonce_h * >(tmplink->data));
 768             dlinkNodeDelete(tmplink);
 769             link = NULL;
 770         }
 771     }
 772
 773     /* this reference to user was not locked because freeeing the user frees
 774      * the nonce too.
 775      */
 776     nonce->user = NULL;
 777 }
 778
 779 /* authDigestUserLinkNonce: add a nonce to a given user's struct */
 780
 781 static void
 782 authDigestUserLinkNonce(DigestUser * user, digest_nonce_h * nonce)
 783 {
 784     dlink_node *node;
 785     digest_user_h *digest_user;
 786
 787     if (!user || !nonce)
 788         return;
 789
 790     digest_user = user;
 791
 792     node = digest_user->nonces.head;
 793
 794     while (node && (node->data != nonce))
 795         node = node->next;
 796
 797     if (node)
 798         return;
 799
 800     node = dlinkNodeNew();
 801
 802     dlinkAddTail(nonce, node, &digest_user->nonces);
 803
 804     authDigestNonceLink(nonce);
 805
 806     /* ping this nonce to this auth user */
 807     assert((nonce->user == NULL) || (nonce->user == user));
 808
 809     /* we don't lock this reference because removing the user removes the
 810      * hash too. Of course if that changes we're stuffed so read the code huh?
 811      */
 812     nonce->user = user;
 813 }
 814
 815 /* setup the necessary info to log the username */
 816 static AuthUserRequest::Pointer
 817 authDigestLogUsername(char *username, AuthUserRequest::Pointer auth_user_request)
 818 {
 819     assert(auth_user_request != NULL);
 820
 821     /* log the username */
 822     debugs(29, 9, "authDigestLogUsername: Creating new user for logging '" << username << "'");
 823     digest_user_h *digest_user = new DigestUser(static_cast<AuthDigestConfig*>(AuthConfig::Find("digest")));
 824     /* save the credentials */
 825     digest_user->username(username);
 826     /* set the auth_user type */
 827     digest_user->auth_type = AUTH_BROKEN;
 828     /* link the request to the user */
 829     auth_user_request->user(digest_user);
 830     digest_user->lock();
 831 #if USER_REQUEST_LOOP_DEAD
 832     digest_user->addRequest(auth_user_request);
 833 #endif
 834     return auth_user_request;
 835 }
 836
 837 /*
 838  * Decode a Digest [Proxy-]Auth string, placing the results in the passed
 839  * Auth_user structure.
 840  */
 841 AuthUserRequest::Pointer
 842 AuthDigestConfig::decode(char const *proxy_auth)
 843 {
 844     const char *item;
 845     const char *p;
 846     const char *pos = NULL;
 847     char *username = NULL;
 848     digest_nonce_h *nonce;
 849     int ilen;
 850
 851     debugs(29, 9, "authenticateDigestDecodeAuth: beginning");
 852
 853     AuthDigestUserRequest *digest_request = new AuthDigestUserRequest();
 854
 855     /* trim DIGEST from string */
 856
 857     while (xisgraph(*proxy_auth))
 858         proxy_auth++;
 859
 860     /* Trim leading whitespace before decoding */
 861     while (xisspace(*proxy_auth))
 862         proxy_auth++;
 863
 864     String temp(proxy_auth);
 865
 866     while (strListGetItem(&temp, ',', &item, &ilen, &pos)) {
 867         String value;
 868         size_t nlen;
 869         /* isolate directive name */
 870         if ((p = (const char *)memchr(item, '=', ilen)) && (p - item < ilen)) {
 871             nlen = p++ - item;
 872             if (!httpHeaderParseQuotedString(p, &value))
 873                 value.limitInit(p, ilen - (p - item));
 874         } else
 875             nlen = ilen;
 876
 877         if (!value.defined()) {
 878             debugs(29, 9, "authDigestDecodeAuth: Failed to parse attribute '" << temp << "' in '" << proxy_auth << "'");
 879             continue;
 880         }
 881
 882         /* find type */
 883         http_digest_attr_type type = (http_digest_attr_type)httpHeaderIdByName(item, nlen, DigestFieldsInfo, DIGEST_ENUM_END);
 884
 885         switch (type) {
 886         case DIGEST_USERNAME:
 887             safe_free(username);
 888             username = xstrndup(value.rawBuf(), value.size() + 1);
 889             debugs(29, 9, "authDigestDecodeAuth: Found Username '" << username << "'");
 890             break;
 891
 892         case DIGEST_REALM:
 893             safe_free(digest_request->realm);
 894             digest_request->realm = xstrndup(value.rawBuf(), value.size() + 1);
 895             debugs(29, 9, "authDigestDecodeAuth: Found realm '" << digest_request->realm << "'");
 896             break;
 897
 898         case DIGEST_QOP:
 899             safe_free(digest_request->qop);
 900             digest_request->qop = xstrndup(value.rawBuf(), value.size() + 1);
 901             debugs(29, 9, "authDigestDecodeAuth: Found qop '" << digest_request->qop << "'");
 902             break;
 903
 904         case DIGEST_ALGORITHM:
 905             safe_free(digest_request->algorithm);
 906             digest_request->algorithm = xstrndup(value.rawBuf(), value.size() + 1);
 907             debugs(29, 9, "authDigestDecodeAuth: Found algorithm '" << digest_request->algorithm << "'");
 908             break;
 909
 910         case DIGEST_URI:
 911             safe_free(digest_request->uri);
 912             digest_request->uri = xstrndup(value.rawBuf(), value.size() + 1);
 913             debugs(29, 9, "authDigestDecodeAuth: Found uri '" << digest_request->uri << "'");
 914             break;
 915
 916         case DIGEST_NONCE:
 917             safe_free(digest_request->nonceb64);
 918             digest_request->nonceb64 = xstrndup(value.rawBuf(), value.size() + 1);
 919             debugs(29, 9, "authDigestDecodeAuth: Found nonce '" << digest_request->nonceb64 << "'");
 920             break;
 921
 922         case DIGEST_NC:
 923             if (value.size() != 8) {
 924                 debugs(29, 9, "authDigestDecodeAuth: Invalid nc '" << value << "' in '" << temp << "'");
 925             }
 926             xstrncpy(digest_request->nc, value.rawBuf(), value.size() + 1);
 927             debugs(29, 9, "authDigestDecodeAuth: Found noncecount '" << digest_request->nc << "'");
 928             break;
 929
 930         case DIGEST_CNONCE:
 931             safe_free(digest_request->cnonce);
 932             digest_request->cnonce = xstrndup(value.rawBuf(), value.size() + 1);
 933             debugs(29, 9, "authDigestDecodeAuth: Found cnonce '" << digest_request->cnonce << "'");
 934             break;
 935
 936         case DIGEST_RESPONSE:
 937             safe_free(digest_request->response);
 938             digest_request->response = xstrndup(value.rawBuf(), value.size() + 1);
 939             debugs(29, 9, "authDigestDecodeAuth: Found response '" << digest_request->response << "'");
 940             break;
 941
 942         default:
 943             debugs(29, 3, "authDigestDecodeAuth: Unknown attribute '" << item << "' in '" << temp << "'");
 944
 945         }
 946     }
 947
 948     temp.clean();
 949
 950
 951     /* now we validate the data given to us */
 952
 953     /*
 954      * TODO: on invalid parameters we should return 400, not 407.
 955      * Find some clean way of doing this. perhaps return a valid
 956      * struct, and set the direction to clientwards combined with
 957      * a change to the clientwards handling code (ie let the
 958      * clientwards call set the error type (but limited to known
 959      * correct values - 400/401/407
 960      */
 961
 962     /* 2069 requirements */
 963
 964     /* do we have a username ? */
 965     if (!username || username[0] == '\0') {
 966         debugs(29, 2, "authenticateDigestDecode: Empty or not present username");
 967         return authDigestLogUsername(username, digest_request);
 968     }
 969
 970     /* do we have a realm ? */
 971     if (!digest_request->realm || digest_request->realm[0] == '\0') {
 972         debugs(29, 2, "authenticateDigestDecode: Empty or not present realm");
 973         return authDigestLogUsername(username, digest_request);
 974     }
 975
 976     /* and a nonce? */
 977     if (!digest_request->nonceb64 || digest_request->nonceb64[0] == '\0') {
 978         debugs(29, 2, "authenticateDigestDecode: Empty or not present nonce");
 979         return authDigestLogUsername(username, digest_request);
 980     }
 981
 982     /* we can't check the URI just yet. We'll check it in the
 983      * authenticate phase, but needs to be given */
 984     if (!digest_request->uri || digest_request->uri[0] == '\0') {
 985         debugs(29, 2, "authenticateDigestDecode: Missing URI field");
 986         return authDigestLogUsername(username, digest_request);
 987     }
 988
 989     /* is the response the correct length? */
 990     if (!digest_request->response || strlen(digest_request->response) != 32) {
 991         debugs(29, 2, "authenticateDigestDecode: Response length invalid");
 992         return authDigestLogUsername(username, digest_request);
 993     }
 994
 995     /* check the algorithm is present and supported */
 996     if (!digest_request->algorithm)
 997         digest_request->algorithm = xstrndup("MD5", 4);
 998     else if (strcmp(digest_request->algorithm, "MD5")
 999              && strcmp(digest_request->algorithm, "MD5-sess")) {
1000         debugs(29, 2, "authenticateDigestDecode: invalid algorithm specified!");
1001         return authDigestLogUsername(username, digest_request);
1002     }
1003
1004     /* 2617 requirements, indicated by qop */
1005     if (digest_request->qop) {
1006
1007         /* check the qop is what we expected. */
1008         if (strcmp(digest_request->qop, QOP_AUTH) != 0) {
1009             /* we received a qop option we didn't send */
1010             debugs(29, 2, "authenticateDigestDecode: Invalid qop option received");
1011             return authDigestLogUsername(username, digest_request);
1012         }
1013
1014         /* check cnonce */
1015         if (!digest_request->cnonce || digest_request->cnonce[0] == '\0') {
1016             debugs(29, 2, "authenticateDigestDecode: Missing cnonce field");
1017             return authDigestLogUsername(username, digest_request);
1018         }
1019
1020         /* check nc */
1021         if (strlen(digest_request->nc) != 8 || strspn(digest_request->nc, "0123456789abcdefABCDEF") != 8) {
1022             debugs(29, 2, "authenticateDigestDecode: invalid nonce count");
1023             return authDigestLogUsername(username, digest_request);
1024         }
1025     } else {
1026         /* cnonce and nc both require qop */
1027         if (digest_request->cnonce || digest_request->nc) {
1028             debugs(29, 2, "authenticateDigestDecode: missing qop!");
1029             return authDigestLogUsername(username, digest_request);
1030         }
1031     }
1032
1033     /** below nonce state dependent **/
1034
1035     /* now the nonce */
1036     nonce = authenticateDigestNonceFindNonce(digest_request->nonceb64);
1037     if (!nonce) {
1038         /* we couldn't find a matching nonce! */
1039         debugs(29, 2, "authenticateDigestDecode: Unexpected or invalid nonce received");
1040         digest_request->credentials(AuthDigestUserRequest::Failed);
1041         return authDigestLogUsername(username, digest_request);
1042     }
1043
1044     digest_request->nonce = nonce;
1045     authDigestNonceLink(nonce);
1046
1047     /* check that we're not being hacked / the username hasn't changed */
1048     if (nonce->user && strcmp(username, nonce->user->username())) {
1049         debugs(29, 2, "authenticateDigestDecode: Username for the nonce does not equal the username for the request");
1050         return authDigestLogUsername(username, digest_request);
1051     }
1052
1053     /* the method we'll check at the authenticate step as well */
1054
1055
1056     /* we don't send or parse opaques. Ok so we're flexable ... */
1057
1058     /* find the user */
1059     digest_user_h *digest_user;
1060
1061     AuthUser *auth_user;
1062
1063     if ((auth_user = authDigestUserFindUsername(username)) == NULL) {
1064         /* the user doesn't exist in the username cache yet */
1065         debugs(29, 9, "authDigestDecodeAuth: Creating new digest user '" << username << "'");
1066         digest_user = new DigestUser(this);
1067         /* auth_user is a parent */
1068         auth_user = digest_user;
1069         /* save the username */
1070         digest_user->username(username);
1071         /* set the user type */
1072         digest_user->auth_type = AUTH_DIGEST;
1073         /* this auth_user struct is the one to get added to the
1074          * username cache */
1075         /* store user in hash's */
1076         digest_user->addToNameCache();
1077
1078         /*
1079          * Add the digest to the user so we can tell if a hacking
1080          * or spoofing attack is taking place. We do this by assuming
1081          * the user agent won't change user name without warning.
1082          */
1083         authDigestUserLinkNonce(digest_user, nonce);
1084     } else {
1085         debugs(29, 9, "authDigestDecodeAuth: Found user '" << username << "' in the user cache as '" << auth_user << "'");
1086         digest_user = static_cast < digest_user_h * >(auth_user);
1087         xfree(username);
1088     }
1089
1090     /*link the request and the user */
1091     assert(digest_request != NULL);
1092
1093     digest_user->lock();
1094     digest_request->user(digest_user);
1095 #if USER_REQUEST_LOOP_DEAD
1096     digest_user->addRequest(digest_request);
1097 #endif
1098
1099     debugs(29, 9, "username = '" << digest_user->username() << "'\nrealm = '" <<
1100            digest_request->realm << "'\nqop = '" << digest_request->qop <<
1101            "'\nalgorithm = '" << digest_request->algorithm << "'\nuri = '" <<
1102            digest_request->uri << "'\nnonce = '" << digest_request->nonceb64 <<
1103            "'\nnc = '" << digest_request->nc << "'\ncnonce = '" <<
1104            digest_request->cnonce << "'\nresponse = '" <<
1105            digest_request->response << "'\ndigestnonce = '" << nonce << "'");
1106
1107     return digest_request;
1108 }
1109
1110 DigestUser::DigestUser (AuthConfig *aConfig) : AuthUser (aConfig), HA1created (0)
1111 {}