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 "mgr/Registration.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->freeOne(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::Pointer
 484 authDigestUserFindUsername(const char *username)
 485 {
 486     AuthUserHashPointer *usernamehash;
 487     debugs(29, 9, HERE << "Looking for user '" << username << "'");
 488
 489     if (username && (usernamehash = static_cast < auth_user_hash_pointer * >(hash_lookup(proxy_auth_username_cache, username)))) {
 490         while ((usernamehash->user()->auth_type != AUTH_DIGEST) && (usernamehash->next))
 491             usernamehash = static_cast<AuthUserHashPointer *>(usernamehash->next);
 492
 493         if (usernamehash->user()->auth_type == AUTH_DIGEST) {
 494             return usernamehash->user();
 495         }
 496     }
 497
 498     return NULL;
 499 }
 500
 501 void
 502 AuthDigestConfig::rotateHelpers()
 503 {
 504     /* schedule closure of existing helpers */
 505     if (digestauthenticators) {
 506         helperShutdown(digestauthenticators);
 507     }
 508
 509     /* NP: dynamic helper restart will ensure they start up again as needed. */
 510 }
 511
 512 /** delete the digest request structure. Does NOT delete related structures */
 513 void
 514 digestScheme::done()
 515 {
 516     /** \todo this should be a Config call. */
 517
 518     if (digestauthenticators)
 519         helperShutdown(digestauthenticators);
 520
 521     if (DigestFieldsInfo) {
 522         httpHeaderDestroyFieldsInfo(DigestFieldsInfo, DIGEST_ENUM_END);
 523         DigestFieldsInfo = NULL;
 524     }
 525
 526     authdigest_initialised = 0;
 527
 528     if (!shutting_down) {
 529         authenticateDigestNonceReconfigure();
 530         return;
 531     }
 532
 533     delete digestauthenticators;
 534     digestauthenticators = NULL;
 535
 536     PurgeCredentialsCache();
 537     authenticateDigestNonceShutdown();
 538     debugs(29, 2, "authenticateDigestDone: Digest authentication shut down.");
 539
 540     /* clear the global handle to this scheme. */
 541     _instance = NULL;
 542 }
 543
 544 void
 545 AuthDigestConfig::dump(StoreEntry * entry, const char *name, AuthConfig * scheme)
 546 {
 547     wordlist *list = authenticate;
 548     debugs(29, 9, "authDigestCfgDump: Dumping configuration");
 549     storeAppendPrintf(entry, "%s %s", name, "digest");
 550
 551     while (list != NULL) {
 552         storeAppendPrintf(entry, " %s", list->key);
 553         list = list->next;
 554     }
 555
 556     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",
 557                       name, "digest", digestAuthRealm,
 558                       name, "digest", authenticateChildren.n_max, authenticateChildren.n_startup, authenticateChildren.n_idle, authenticateChildren.concurrency,
 559                       name, "digest", noncemaxuses,
 560                       name, "digest", (int) noncemaxduration,
 561                       name, "digest", (int) nonceGCInterval);
 562 }
 563
 564 bool
 565 AuthDigestConfig::active() const
 566 {
 567     return authdigest_initialised == 1;
 568 }
 569
 570 bool
 571 AuthDigestConfig::configured() const
 572 {
 573     if ((authenticate != NULL) &&
 574             (authenticateChildren.n_max != 0) &&
 575             (digestAuthRealm != NULL) && (noncemaxduration > -1))
 576         return true;
 577
 578     return false;
 579 }
 580
 581 /* add the [www-|Proxy-]authenticate header on a 407 or 401 reply */
 582 void
 583 AuthDigestConfig::fixHeader(AuthUserRequest::Pointer auth_user_request, HttpReply *rep, http_hdr_type hdrType, HttpRequest * request)
 584 {
 585     if (!authenticate)
 586         return;
 587
 588     int stale = 0;
 589
 590     if (auth_user_request != NULL) {
 591         AuthDigestUserRequest *digest_request;
 592         digest_request = dynamic_cast<AuthDigestUserRequest*>(auth_user_request.getRaw());
 593         assert (digest_request != NULL);
 594
 595         stale = !digest_request->flags.invalid_password;
 596     }
 597
 598     /* on a 407 or 401 we always use a new nonce */
 599     digest_nonce_h *nonce = authenticateDigestNonceNew();
 600
 601     debugs(29, 9, "authenticateFixHeader: Sending type:" << hdrType <<
 602            " header: 'Digest realm=\"" << digestAuthRealm << "\", nonce=\"" <<
 603            authenticateDigestNonceNonceb64(nonce) << "\", qop=\"" << QOP_AUTH <<
 604            "\", stale=" << (stale ? "true" : "false"));
 605
 606     /* in the future, for WWW auth we may want to support the domain entry */
 607     httpHeaderPutStrf(&rep->header, hdrType, "Digest realm=\"%s\", nonce=\"%s\", qop=\"%s\", stale=%s", digestAuthRealm, authenticateDigestNonceNonceb64(nonce), QOP_AUTH, stale ? "true" : "false");
 608 }
 609
 610 DigestUser::~DigestUser()
 611 {
 612     dlink_node *link, *tmplink;
 613     link = nonces.head;
 614
 615     while (link) {
 616         tmplink = link;
 617         link = link->next;
 618         dlinkDelete(tmplink, &nonces);
 619         authDigestNoncePurge(static_cast < digest_nonce_h * >(tmplink->data));
 620         authDigestNonceUnlink(static_cast < digest_nonce_h * >(tmplink->data));
 621         dlinkNodeDelete(tmplink);
 622     }
 623 }
 624
 625 int32_t
 626 DigestUser::ttl() const
 627 {
 628     int32_t global_ttl = static_cast<int32_t>(expiretime - squid_curtime + Config.authenticateTTL);
 629
 630     /* find the longest lasting nonce. */
 631     int32_t latest_nonce = -1;
 632     dlink_node *link = nonces.head;
 633     while (link) {
 634         digest_nonce_h *nonce = static_cast<digest_nonce_h *>(link->data);
 635         if (nonce->flags.valid && nonce->noncedata.creationtime > latest_nonce)
 636             latest_nonce = nonce->noncedata.creationtime;
 637
 638         link = link->next;
 639     }
 640     if (latest_nonce == -1)
 641         return min(-1, global_ttl);
 642
 643     int32_t nonce_ttl = latest_nonce - current_time.tv_sec + static_cast<AuthDigestConfig*>(AuthConfig::Find("digest"))->noncemaxduration;
 644
 645     return min(nonce_ttl, global_ttl);
 646 }
 647
 648 /* Initialize helpers and the like for this auth scheme. Called AFTER parsing the
 649  * config file */
 650 void
 651 AuthDigestConfig::init(AuthConfig * scheme)
 652 {
 653     if (authenticate) {
 654         DigestFieldsInfo = httpHeaderBuildFieldsInfo(DigestAttrs, DIGEST_ENUM_END);
 655         authenticateDigestNonceSetup();
 656         authdigest_initialised = 1;
 657
 658         if (digestauthenticators == NULL)
 659             digestauthenticators = new helper("digestauthenticator");
 660
 661         digestauthenticators->cmdline = authenticate;
 662
 663         digestauthenticators->childs = authenticateChildren;
 664
 665         digestauthenticators->ipc_type = IPC_STREAM;
 666
 667         helperOpenServers(digestauthenticators);
 668
 669         CBDATA_INIT_TYPE(authenticateStateData);
 670     }
 671 }
 672
 673 void
 674 AuthDigestConfig::registerWithCacheManager(void)
 675 {
 676     Mgr::RegisterAction("digestauthenticator",
 677                         "Digest User Authenticator Stats",
 678                         authenticateDigestStats, 0, 1);
 679 }
 680
 681 /* free any allocated configuration details */
 682 void
 683 AuthDigestConfig::done()
 684 {
 685     if (authenticate)
 686         wordlistDestroy(&authenticate);
 687
 688     safe_free(digestAuthRealm);
 689 }
 690
 691 AuthDigestConfig::AuthDigestConfig()
 692 {
 693     /* TODO: move into initialisation list */
 694     /* 5 minutes */
 695     nonceGCInterval = 5 * 60;
 696     /* 30 minutes */
 697     noncemaxduration = 30 * 60;
 698     /* 50 requests */
 699     noncemaxuses = 50;
 700     /* Not strict nonce count behaviour */
 701     NonceStrictness = 0;
 702     /* Verify nonce count */
 703     CheckNonceCount = 1;
 704 }
 705
 706 void
 707 AuthDigestConfig::parse(AuthConfig * scheme, int n_configured, char *param_str)
 708 {
 709     if (strcasecmp(param_str, "program") == 0) {
 710         if (authenticate)
 711             wordlistDestroy(&authenticate);
 712
 713         parse_wordlist(&authenticate);
 714
 715         requirePathnameExists("auth_param digest program", authenticate->key);
 716     } else if (strcasecmp(param_str, "children") == 0) {
 717         authenticateChildren.parseConfig();
 718     } else if (strcasecmp(param_str, "realm") == 0) {
 719         parse_eol(&digestAuthRealm);
 720     } else if (strcasecmp(param_str, "nonce_garbage_interval") == 0) {
 721         parse_time_t(&nonceGCInterval);
 722     } else if (strcasecmp(param_str, "nonce_max_duration") == 0) {
 723         parse_time_t(&noncemaxduration);
 724     } else if (strcasecmp(param_str, "nonce_max_count") == 0) {
 725         parse_int((int *) &noncemaxuses);
 726     } else if (strcasecmp(param_str, "nonce_strictness") == 0) {
 727         parse_onoff(&NonceStrictness);
 728     } else if (strcasecmp(param_str, "check_nonce_count") == 0) {
 729         parse_onoff(&CheckNonceCount);
 730     } else if (strcasecmp(param_str, "post_workaround") == 0) {
 731         parse_onoff(&PostWorkaround);
 732     } else if (strcasecmp(param_str, "utf8") == 0) {
 733         parse_onoff(&utf8);
 734     } else {
 735         debugs(29, 0, "unrecognised digest auth scheme parameter '" << param_str << "'");
 736     }
 737 }
 738
 739 const char *
 740 AuthDigestConfig::type() const
 741 {
 742     return digestScheme::GetInstance()->type();
 743 }
 744
 745
 746 static void
 747 authenticateDigestStats(StoreEntry * sentry)
 748 {
 749     helperStats(sentry, digestauthenticators, "Digest Authenticator Statistics");
 750 }
 751
 752 /* NonceUserUnlink: remove the reference to auth_user and unlink the node from the list */
 753
 754 static void
 755 authDigestNonceUserUnlink(digest_nonce_h * nonce)
 756 {
 757     DigestUser *digest_user;
 758     dlink_node *link, *tmplink;
 759
 760     if (!nonce)
 761         return;
 762
 763     if (!nonce->user)
 764         return;
 765
 766     digest_user = nonce->user;
 767
 768     /* unlink from the user list. Yes we're crossing structures but this is the only
 769      * time this code is needed
 770      */
 771     link = digest_user->nonces.head;
 772
 773     while (link) {
 774         tmplink = link;
 775         link = link->next;
 776
 777         if (tmplink->data == nonce) {
 778             dlinkDelete(tmplink, &digest_user->nonces);
 779             authDigestNonceUnlink(static_cast < digest_nonce_h * >(tmplink->data));
 780             dlinkNodeDelete(tmplink);
 781             link = NULL;
 782         }
 783     }
 784
 785     /* this reference to user was not locked because freeeing the user frees
 786      * the nonce too.
 787      */
 788     nonce->user = NULL;
 789 }
 790
 791 /* authDigestUserLinkNonce: add a nonce to a given user's struct */
 792
 793 static void
 794 authDigestUserLinkNonce(DigestUser * user, digest_nonce_h * nonce)
 795 {
 796     dlink_node *node;
 797     DigestUser *digest_user;
 798
 799     if (!user || !nonce)
 800         return;
 801
 802     digest_user = user;
 803
 804     node = digest_user->nonces.head;
 805
 806     while (node && (node->data != nonce))
 807         node = node->next;
 808
 809     if (node)
 810         return;
 811
 812     node = dlinkNodeNew();
 813
 814     dlinkAddTail(nonce, node, &digest_user->nonces);
 815
 816     authDigestNonceLink(nonce);
 817
 818     /* ping this nonce to this auth user */
 819     assert((nonce->user == NULL) || (nonce->user == user));
 820
 821     /* we don't lock this reference because removing the user removes the
 822      * hash too. Of course if that changes we're stuffed so read the code huh?
 823      */
 824     nonce->user = user;
 825 }
 826
 827 /* setup the necessary info to log the username */
 828 static AuthUserRequest::Pointer
 829 authDigestLogUsername(char *username, AuthUserRequest::Pointer auth_user_request)
 830 {
 831     assert(auth_user_request != NULL);
 832
 833     /* log the username */
 834     debugs(29, 9, "authDigestLogUsername: Creating new user for logging '" << username << "'");
 835     AuthUser::Pointer digest_user = new DigestUser(static_cast<AuthDigestConfig*>(AuthConfig::Find("digest")));
 836     /* save the credentials */
 837     digest_user->username(username);
 838     /* set the auth_user type */
 839     digest_user->auth_type = AUTH_BROKEN;
 840     /* link the request to the user */
 841     auth_user_request->user(digest_user);
 842     return auth_user_request;
 843 }
 844
 845 /*
 846  * Decode a Digest [Proxy-]Auth string, placing the results in the passed
 847  * Auth_user structure.
 848  */
 849 AuthUserRequest::Pointer
 850 AuthDigestConfig::decode(char const *proxy_auth)
 851 {
 852     const char *item;
 853     const char *p;
 854     const char *pos = NULL;
 855     char *username = NULL;
 856     digest_nonce_h *nonce;
 857     int ilen;
 858
 859     debugs(29, 9, "authenticateDigestDecodeAuth: beginning");
 860
 861     AuthDigestUserRequest *digest_request = new AuthDigestUserRequest();
 862
 863     /* trim DIGEST from string */
 864
 865     while (xisgraph(*proxy_auth))
 866         proxy_auth++;
 867
 868     /* Trim leading whitespace before decoding */
 869     while (xisspace(*proxy_auth))
 870         proxy_auth++;
 871
 872     String temp(proxy_auth);
 873
 874     while (strListGetItem(&temp, ',', &item, &ilen, &pos)) {
 875         /* isolate directive name & value */
 876         size_t nlen;
 877         size_t vlen;
 878         if ((p = (const char *)memchr(item, '=', ilen)) && (p - item < ilen)) {
 879             nlen = p++ - item;
 880             vlen = ilen - (p - item);
 881         } else {
 882             nlen = ilen;
 883             vlen = 0;
 884         }
 885
 886         /* parse value. auth-param     = token "=" ( token | quoted-string ) */
 887         String value;
 888         if (vlen > 0) {
 889             if (*p == '"') {
 890                 if (!httpHeaderParseQuotedString(p, vlen, &value)) {
 891                     debugs(29, 9, "authDigestDecodeAuth: Failed to parse attribute '" << item << "' in '" << temp << "'");
 892                     continue;
 893                 }
 894             } else {
 895                 value.limitInit(p, vlen);
 896             }
 897         } else {
 898             debugs(29, 9, "authDigestDecodeAuth: Failed to parse attribute '" << item << "' in '" << temp << "'");
 899             continue;
 900         }
 901
 902         /* find type */
 903         http_digest_attr_type type = (http_digest_attr_type)httpHeaderIdByName(item, nlen, DigestFieldsInfo, DIGEST_ENUM_END);
 904
 905         switch (type) {
 906         case DIGEST_USERNAME:
 907             safe_free(username);
 908             username = xstrndup(value.rawBuf(), value.size() + 1);
 909             debugs(29, 9, "authDigestDecodeAuth: Found Username '" << username << "'");
 910             break;
 911
 912         case DIGEST_REALM:
 913             safe_free(digest_request->realm);
 914             digest_request->realm = xstrndup(value.rawBuf(), value.size() + 1);
 915             debugs(29, 9, "authDigestDecodeAuth: Found realm '" << digest_request->realm << "'");
 916             break;
 917
 918         case DIGEST_QOP:
 919             safe_free(digest_request->qop);
 920             digest_request->qop = xstrndup(value.rawBuf(), value.size() + 1);
 921             debugs(29, 9, "authDigestDecodeAuth: Found qop '" << digest_request->qop << "'");
 922             break;
 923
 924         case DIGEST_ALGORITHM:
 925             safe_free(digest_request->algorithm);
 926             digest_request->algorithm = xstrndup(value.rawBuf(), value.size() + 1);
 927             debugs(29, 9, "authDigestDecodeAuth: Found algorithm '" << digest_request->algorithm << "'");
 928             break;
 929
 930         case DIGEST_URI:
 931             safe_free(digest_request->uri);
 932             digest_request->uri = xstrndup(value.rawBuf(), value.size() + 1);
 933             debugs(29, 9, "authDigestDecodeAuth: Found uri '" << digest_request->uri << "'");
 934             break;
 935
 936         case DIGEST_NONCE:
 937             safe_free(digest_request->nonceb64);
 938             digest_request->nonceb64 = xstrndup(value.rawBuf(), value.size() + 1);
 939             debugs(29, 9, "authDigestDecodeAuth: Found nonce '" << digest_request->nonceb64 << "'");
 940             break;
 941
 942         case DIGEST_NC:
 943             if (value.size() != 8) {
 944                 debugs(29, 9, "authDigestDecodeAuth: Invalid nc '" << value << "' in '" << temp << "'");
 945             }
 946             xstrncpy(digest_request->nc, value.rawBuf(), value.size() + 1);
 947             debugs(29, 9, "authDigestDecodeAuth: Found noncecount '" << digest_request->nc << "'");
 948             break;
 949
 950         case DIGEST_CNONCE:
 951             safe_free(digest_request->cnonce);
 952             digest_request->cnonce = xstrndup(value.rawBuf(), value.size() + 1);
 953             debugs(29, 9, "authDigestDecodeAuth: Found cnonce '" << digest_request->cnonce << "'");
 954             break;
 955
 956         case DIGEST_RESPONSE:
 957             safe_free(digest_request->response);
 958             digest_request->response = xstrndup(value.rawBuf(), value.size() + 1);
 959             debugs(29, 9, "authDigestDecodeAuth: Found response '" << digest_request->response << "'");
 960             break;
 961
 962         default:
 963             debugs(29, 3, "authDigestDecodeAuth: Unknown attribute '" << item << "' in '" << temp << "'");
 964             break;
 965         }
 966     }
 967
 968     temp.clean();
 969
 970
 971     /* now we validate the data given to us */
 972
 973     /*
 974      * TODO: on invalid parameters we should return 400, not 407.
 975      * Find some clean way of doing this. perhaps return a valid
 976      * struct, and set the direction to clientwards combined with
 977      * a change to the clientwards handling code (ie let the
 978      * clientwards call set the error type (but limited to known
 979      * correct values - 400/401/407
 980      */
 981
 982     /* 2069 requirements */
 983
 984     /* do we have a username ? */
 985     if (!username || username[0] == '\0') {
 986         debugs(29, 2, "authenticateDigestDecode: Empty or not present username");
 987         return authDigestLogUsername(username, digest_request);
 988     }
 989
 990     /* Sanity check of the username.
 991      * " can not be allowed in usernames until * the digest helper protocol
 992      * have been redone
 993      */
 994     if (strchr(username, '"')) {
 995         debugs(29, 2, "authenticateDigestDecode: Unacceptable username '" << username << "'");
 996         return authDigestLogUsername(username, digest_request);
 997     }
 998
 999     /* do we have a realm ? */
1000     if (!digest_request->realm || digest_request->realm[0] == '\0') {
1001         debugs(29, 2, "authenticateDigestDecode: Empty or not present realm");
1002         return authDigestLogUsername(username, digest_request);
1003     }
1004
1005     /* and a nonce? */
1006     if (!digest_request->nonceb64 || digest_request->nonceb64[0] == '\0') {
1007         debugs(29, 2, "authenticateDigestDecode: Empty or not present nonce");
1008         return authDigestLogUsername(username, digest_request);
1009     }
1010
1011     /* we can't check the URI just yet. We'll check it in the
1012      * authenticate phase, but needs to be given */
1013     if (!digest_request->uri || digest_request->uri[0] == '\0') {
1014         debugs(29, 2, "authenticateDigestDecode: Missing URI field");
1015         return authDigestLogUsername(username, digest_request);
1016     }
1017
1018     /* is the response the correct length? */
1019     if (!digest_request->response || strlen(digest_request->response) != 32) {
1020         debugs(29, 2, "authenticateDigestDecode: Response length invalid");
1021         return authDigestLogUsername(username, digest_request);
1022     }
1023
1024     /* check the algorithm is present and supported */
1025     if (!digest_request->algorithm)
1026         digest_request->algorithm = xstrndup("MD5", 4);
1027     else if (strcmp(digest_request->algorithm, "MD5")
1028              && strcmp(digest_request->algorithm, "MD5-sess")) {
1029         debugs(29, 2, "authenticateDigestDecode: invalid algorithm specified!");
1030         return authDigestLogUsername(username, digest_request);
1031     }
1032
1033     /* 2617 requirements, indicated by qop */
1034     if (digest_request->qop) {
1035
1036         /* check the qop is what we expected. */
1037         if (strcmp(digest_request->qop, QOP_AUTH) != 0) {
1038             /* we received a qop option we didn't send */
1039             debugs(29, 2, "authenticateDigestDecode: Invalid qop option received");
1040             return authDigestLogUsername(username, digest_request);
1041         }
1042
1043         /* check cnonce */
1044         if (!digest_request->cnonce || digest_request->cnonce[0] == '\0') {
1045             debugs(29, 2, "authenticateDigestDecode: Missing cnonce field");
1046             return authDigestLogUsername(username, digest_request);
1047         }
1048
1049         /* check nc */
1050         if (strlen(digest_request->nc) != 8 || strspn(digest_request->nc, "0123456789abcdefABCDEF") != 8) {
1051             debugs(29, 2, "authenticateDigestDecode: invalid nonce count");
1052             return authDigestLogUsername(username, digest_request);
1053         }
1054     } else {
1055         /* cnonce and nc both require qop */
1056         if (digest_request->cnonce || digest_request->nc) {
1057             debugs(29, 2, "authenticateDigestDecode: missing qop!");
1058             return authDigestLogUsername(username, digest_request);
1059         }
1060     }
1061
1062     /** below nonce state dependent **/
1063
1064     /* now the nonce */
1065     nonce = authenticateDigestNonceFindNonce(digest_request->nonceb64);
1066     if (!nonce) {
1067         /* we couldn't find a matching nonce! */
1068         debugs(29, 2, "authenticateDigestDecode: Unexpected or invalid nonce received");
1069         digest_request->user()->credentials(AuthUser::Failed);
1070         return authDigestLogUsername(username, digest_request);
1071     }
1072
1073     digest_request->nonce = nonce;
1074     authDigestNonceLink(nonce);
1075
1076     /* check that we're not being hacked / the username hasn't changed */
1077     if (nonce->user && strcmp(username, nonce->user->username())) {
1078         debugs(29, 2, "authenticateDigestDecode: Username for the nonce does not equal the username for the request");
1079         return authDigestLogUsername(username, digest_request);
1080     }
1081
1082     /* the method we'll check at the authenticate step as well */
1083
1084
1085     /* we don't send or parse opaques. Ok so we're flexable ... */
1086
1087     /* find the user */
1088     DigestUser *digest_user;
1089
1090     AuthUser::Pointer auth_user;
1091
1092     if ((auth_user = authDigestUserFindUsername(username)) == NULL) {
1093         /* the user doesn't exist in the username cache yet */
1094         debugs(29, 9, "authDigestDecodeAuth: Creating new digest user '" << username << "'");
1095         digest_user = new DigestUser(this);
1096         /* auth_user is a parent */
1097         auth_user = digest_user;
1098         /* save the username */
1099         digest_user->username(username);
1100         /* set the user type */
1101         digest_user->auth_type = AUTH_DIGEST;
1102         /* this auth_user struct is the one to get added to the
1103          * username cache */
1104         /* store user in hash's */
1105         digest_user->addToNameCache();
1106
1107         /*
1108          * Add the digest to the user so we can tell if a hacking
1109          * or spoofing attack is taking place. We do this by assuming
1110          * the user agent won't change user name without warning.
1111          */
1112         authDigestUserLinkNonce(digest_user, nonce);
1113     } else {
1114         debugs(29, 9, "authDigestDecodeAuth: Found user '" << username << "' in the user cache as '" << auth_user << "'");
1115         digest_user = static_cast<DigestUser *>(auth_user.getRaw());
1116         xfree(username);
1117     }
1118
1119     /*link the request and the user */
1120     assert(digest_request != NULL);
1121
1122     digest_request->user(digest_user);
1123     debugs(29, 9, "username = '" << digest_user->username() << "'\nrealm = '" <<
1124            digest_request->realm << "'\nqop = '" << digest_request->qop <<
1125            "'\nalgorithm = '" << digest_request->algorithm << "'\nuri = '" <<
1126            digest_request->uri << "'\nnonce = '" << digest_request->nonceb64 <<
1127            "'\nnc = '" << digest_request->nc << "'\ncnonce = '" <<
1128            digest_request->cnonce << "'\nresponse = '" <<
1129            digest_request->response << "'\ndigestnonce = '" << nonce << "'");
1130
1131     return digest_request;
1132 }
1133
1134 DigestUser::DigestUser(AuthConfig *aConfig) : AuthUser(aConfig), HA1created (0)
1135 {}