webcit/context_loop.c

   1 /*
   2  * $Id$
   3  *
   4  * This is the other half of the webserver.  It handles the task of hooking
   5  * up HTTP requests with the sessions they belong to, using HTTP cookies to
   6  * keep track of things.  If the HTTP request doesn't belong to any currently
   7  * active session, a new session is started.
   8  *
   9  */
  10
  11 #include "webcit.h"
  12 #include "webserver.h"
  13
  14 /* Only one thread may manipulate SessionList at a time... */
  15 pthread_mutex_t SessionListMutex;
  16
  17 wcsession *SessionList = NULL; /**< our sessions ????*/
  18
  19 pthread_key_t MyConKey;         /**< TSD key for MySession() */
  20
  21
  22
  23 void DestroySession(wcsession **sessions_to_kill)
  24 {
  25         close((*sessions_to_kill)->serv_sock);
  26         close((*sessions_to_kill)->chat_sock);
  27 /*
  28 //              if ((*sessions_to_kill)->preferences != NULL) {
  29 //                      free((*sessions_to_kill)->preferences);
  30 //              }
  31 */
  32         if ((*sessions_to_kill)->cache_fold != NULL) {
  33                 free((*sessions_to_kill)->cache_fold);
  34         }
  35         DeleteHash(&((*sessions_to_kill)->attachments));
  36         free_march_list((*sessions_to_kill));
  37         DeleteHash(&((*sessions_to_kill)->hash_prefs));
  38         DeleteHash(&((*sessions_to_kill)->IconBarSettings));
  39         DeleteHash(&((*sessions_to_kill)->ServCfg));
  40         FreeStrBuf(&((*sessions_to_kill)->UrlFragment1));
  41         FreeStrBuf(&((*sessions_to_kill)->UrlFragment2));
  42         FreeStrBuf(&((*sessions_to_kill)->UrlFragment3));
  43         FreeStrBuf(&((*sessions_to_kill)->WBuf));
  44         FreeStrBuf(&((*sessions_to_kill)->HBuf));
  45         FreeStrBuf(&((*sessions_to_kill)->CLineBuf));
  46         FreeStrBuf(&((*sessions_to_kill)->wc_username));
  47         FreeStrBuf(&((*sessions_to_kill)->wc_fullname));
  48         FreeStrBuf(&((*sessions_to_kill)->wc_password));
  49         FreeStrBuf(&((*sessions_to_kill)->wc_roomname));
  50         FreeStrBuf(&((*sessions_to_kill)->httpauth_user));
  51         FreeStrBuf(&((*sessions_to_kill)->httpauth_pass));
  52         free((*sessions_to_kill));
  53         (*sessions_to_kill) = NULL;
  54 }
  55
  56 void shutdown_sessions(void)
  57 {
  58         wcsession *sptr;
  59
  60         for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
  61                         sptr->killthis = 1;
  62         }
  63 }
  64
  65 void do_housekeeping(void)
  66 {
  67         wcsession *sptr, *ss;
  68         wcsession *sessions_to_kill = NULL;
  69         int num_sessions = 0;
  70         static int num_threads = MIN_WORKER_THREADS;
  71
  72         /**
  73          * Lock the session list, moving any candidates for euthanasia into
  74          * a separate list.
  75          */
  76         pthread_mutex_lock(&SessionListMutex);
  77         num_sessions = 0;
  78         for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
  79                 ++num_sessions;
  80
  81                 /** Kill idle sessions */
  82                 if ((time(NULL) - (sptr->lastreq)) >
  83                    (time_t) WEBCIT_TIMEOUT) {
  84                         sptr->killthis = 1;
  85                 }
  86
  87                 /** Remove sessions flagged for kill */
  88                 if (sptr->killthis) {
  89
  90                         /** remove session from linked list */
  91                         if (sptr == SessionList) {
  92                                 SessionList = SessionList->next;
  93                         }
  94                         else for (ss=SessionList;ss!=NULL;ss=ss->next) {
  95                                 if (ss->next == sptr) {
  96                                         ss->next = ss->next->next;
  97                                 }
  98                         }
  99
 100                         sptr->next = sessions_to_kill;
 101                         sessions_to_kill = sptr;
 102                 }
 103         }
 104         pthread_mutex_unlock(&SessionListMutex);
 105
 106         /**
 107          * Now free up and destroy the culled sessions.
 108          */
 109         while (sessions_to_kill != NULL) {
 110                 lprintf(3, "Destroying session %d\n", sessions_to_kill->wc_session);
 111                 pthread_mutex_lock(&sessions_to_kill->SessionMutex);
 112                 pthread_mutex_unlock(&sessions_to_kill->SessionMutex);
 113                 sptr = sessions_to_kill->next;
 114
 115                 DestroySession(&sessions_to_kill);
 116                 sessions_to_kill = sptr;
 117                 --num_sessions;
 118         }
 119
 120         /**
 121          * If there are more sessions than threads, then we should spawn
 122          * more threads ... up to a predefined maximum.
 123          */
 124         while ( (num_sessions > num_threads)
 125               && (num_threads <= MAX_WORKER_THREADS) ) {
 126                 spawn_another_worker_thread();
 127                 ++num_threads;
 128                 lprintf(3, "There are %d sessions and %d threads active.\n",
 129                         num_sessions, num_threads);
 130         }
 131 }
 132
 133
 134 /*
 135  * Wake up occasionally and clean house
 136  */
 137 void housekeeping_loop(void)
 138 {
 139         while (1) {
 140                 sleeeeeeeeeep(HOUSEKEEPING);
 141                 do_housekeeping();
 142         }
 143 }
 144
 145
 146 /*
 147  * Create a Session id
 148  * Generate a unique WebCit session ID (which is not the same thing as the
 149  * Citadel session ID).
 150  */
 151 int GenerateSessionID(void)
 152 {
 153         static int seq = (-1);
 154
 155         if (seq < 0) {
 156                 seq = (int) time(NULL);
 157         }
 158
 159         return ++seq;
 160 }
 161
 162 /*
 163  * Collapse multiple cookies on one line
 164  */
 165 int ReqGetStrBuf(int *sock, StrBuf *Target, StrBuf *buf)
 166 {
 167
 168         return ClientGetLine(sock, Target, buf);
 169 }
 170
 171
 172
 173 /*
 174  * lingering_close() a`la Apache. see
 175  * http://www.apache.org/docs/misc/fin_wait_2.html for rationale
 176  */
 177 int lingering_close(int fd)
 178 {
 179         char buf[SIZ];
 180         int i;
 181         fd_set set;
 182         struct timeval tv, start;
 183
 184         gettimeofday(&start, NULL);
 185         shutdown(fd, 1);
 186         do {
 187                 do {
 188                         gettimeofday(&tv, NULL);
 189                         tv.tv_sec = SLEEPING - (tv.tv_sec - start.tv_sec);
 190                         tv.tv_usec = start.tv_usec - tv.tv_usec;
 191                         if (tv.tv_usec < 0) {
 192                                 tv.tv_sec--;
 193                                 tv.tv_usec += 1000000;
 194                         }
 195                         FD_ZERO(&set);
 196                         FD_SET(fd, &set);
 197                         i = select(fd + 1, &set, NULL, NULL, &tv);
 198                 } while (i == -1 && errno == EINTR);
 199
 200                 if (i <= 0)
 201                         break;
 202
 203                 i = read(fd, buf, sizeof buf);
 204         } while (i != 0 && (i != -1 || errno == EINTR));
 205
 206         return close(fd);
 207 }
 208
 209
 210
 211 /*
 212  * Look for commonly-found probes of malware such as worms, viruses, trojans, and Microsoft Office.
 213  * Short-circuit these requests so we don't have to send them through the full processing loop.
 214  */
 215 int is_bogus(StrBuf *http_cmd) {
 216         const char *url;
 217         int i, max;
 218         const char *bogus_prefixes[] = {
 219                 "/scripts/root.exe",    /* Worms and trojans and viruses, oh my! */
 220                 "/c/winnt",
 221                 "/MSADC/",
 222                 "/_vti",                /* Broken Microsoft DAV implementation */
 223                 "/MSOffice",            /* Stoopid MSOffice thinks everyone is IIS */
 224                 "/nonexistenshit"       /* Exploit found in the wild January 2009 */
 225         };
 226
 227         url = ChrPtr(http_cmd);
 228         if (IsEmptyStr(url)) return(1);
 229         ++url;
 230
 231         max = sizeof(bogus_prefixes) / sizeof(char *);
 232
 233         for (i=0; i<max; ++i) {
 234                 if (!strncasecmp(url, bogus_prefixes[i], strlen(bogus_prefixes[i]))) {
 235                         return(2);
 236                 }
 237         }
 238
 239         return(0);      /* probably ok */
 240 }
 241
 242
 243 const char *nix(void *vptr) {return ChrPtr( (StrBuf*)vptr);}
 244
 245 /*
 246  * handle one request
 247  *
 248  * This loop gets called once for every HTTP connection made to WebCit.  At
 249  * this entry point we have an HTTP socket with a browser allegedly on the
 250  * other end, but we have not yet bound to a WebCit session.
 251  *
 252  * The job of this function is to locate the correct session and bind to it,
 253  * or create a session if necessary and bind to it, then run the WebCit
 254  * transaction loop.  Afterwards, we unbind from the session.  When this
 255  * function returns, the worker thread is then free to handle another
 256  * transaction.
 257  */
 258 void context_loop(int *sock)
 259 {
 260         const char *buf;
 261         int desired_session = 0;
 262         int got_cookie = 0;
 263         int gzip_ok = 0;
 264         wcsession *TheSession, *sptr;
 265         char httpauth_string[1024];
 266         char httpauth_user[1024];
 267         char httpauth_pass[1024];
 268         int session_is_new = 0;
 269         int nLine = 0;
 270         int LineLen;
 271         void *vLine;
 272         StrBuf *Buf, *Line, *LastLine, *HeaderName, *ReqLine, *ReqType, *HTTPVersion;
 273         StrBuf *accept_language = NULL;
 274         const char *pch, *pchs, *pche;
 275         HashList *HTTPHeaders;
 276
 277         strcpy(httpauth_string, "");
 278         strcpy(httpauth_user, DEFAULT_HTTPAUTH_USER);
 279         strcpy(httpauth_pass, DEFAULT_HTTPAUTH_PASS);
 280
 281         /*
 282          * Find out what it is that the web browser is asking for
 283          */
 284         HeaderName = NewStrBuf();
 285         Buf = NewStrBuf();
 286         LastLine = NULL;
 287         HTTPHeaders = NewHash(1, NULL);
 288
 289         /*
 290          * Read in the request
 291          */
 292         do {
 293                 nLine ++;
 294                 Line = NewStrBuf();
 295                 if (ReqGetStrBuf(sock, Line, Buf) < 0) return;
 296
 297                 LineLen = StrLength(Line);
 298
 299                 if (nLine == 1) {
 300                         ReqLine = Line;
 301                         continue;
 302                 }
 303                 if (LineLen == 0) {
 304                         FreeStrBuf(&Line);
 305                         continue;
 306                 }
 307
 308                 /* Do we need to Unfold? */
 309                 if ((LastLine != NULL) &&
 310                     (isspace(*ChrPtr(Line)))) {
 311                         pch = pchs = ChrPtr(Line);
 312                         pche = pchs + StrLength(Line);
 313                         while (isspace(*pch) && (pch < pche))
 314                                 pch ++;
 315                         StrBufCutLeft(Line, pch - pchs);
 316                         StrBufAppendBuf(LastLine, Line, 0);
 317                         FreeStrBuf(&Line);
 318                         continue;
 319                 }
 320
 321                 StrBufExtract_token(HeaderName, Line, 0, ':');
 322                 /*/// TODO: filter bad chars! */
 323
 324                 pchs = ChrPtr(Line);
 325                 pch = pchs + StrLength(HeaderName) + 1;
 326                 pche = pchs + StrLength(Line);
 327                 while (isspace(*pch) && (pch < pche))
 328                         pch ++;
 329                 StrBufCutLeft(Line, pch - pchs);
 330
 331                 StrBufUpCase(HeaderName);
 332                 Put(HTTPHeaders, SKEY(HeaderName), Line, HFreeStrBuf);
 333                 LastLine = Line;
 334         } while (LineLen > 0);
 335         FreeStrBuf(&HeaderName);
 336
 337 /*///   dbg_PrintHash(HTTPHeaders, nix, NULL); */
 338
 339
 340         /*
 341          * Can we compress?
 342          */
 343         if (GetHash(HTTPHeaders, HKEY("ACCEPT-ENCODING"), &vLine) &&
 344             (vLine != NULL)) {
 345                 buf = ChrPtr((StrBuf*)vLine);
 346                 if (strstr(&buf[16], "gzip")) {
 347                         gzip_ok = 1;
 348                 }
 349         }
 350
 351         /*
 352          * Browser-based sessions use cookies for session authentication
 353          */
 354         if (GetHash(HTTPHeaders, HKEY("COOKIE"), &vLine) &&
 355             (vLine != NULL)) {
 356                 cookie_to_stuff(vLine, &desired_session,
 357                                 NULL, NULL, NULL);
 358                 got_cookie = 1;
 359         }
 360
 361         /*
 362          * GroupDAV-based sessions use HTTP authentication
 363          */
 364         if (GetHash(HTTPHeaders, HKEY("AUTHORIZATION"), &vLine) &&
 365             (vLine != NULL)) {
 366                 Line = (StrBuf*)vLine;
 367                 if (strncasecmp(ChrPtr(Line), "Basic", 5) == 0) {
 368                         StrBufCutLeft(Line, 6);
 369                         CtdlDecodeBase64(httpauth_string, ChrPtr(Line), StrLength(Line));
 370                         extract_token(httpauth_user, httpauth_string, 0, ':', sizeof httpauth_user);
 371                         extract_token(httpauth_pass, httpauth_string, 1, ':', sizeof httpauth_pass);
 372                 }
 373                 else
 374                         lprintf(1, "Authentication scheme not supported! [%s]\n", ChrPtr(Line));
 375         }
 376
 377         if (GetHash(HTTPHeaders, HKEY("IF-MODIFIED-SINCE"), &vLine) &&
 378             (vLine != NULL)) {
 379                 if_modified_since = httpdate_to_timestamp((StrBuf*)vLine);
 380         }
 381
 382         if (GetHash(HTTPHeaders, HKEY("ACCEPT-LANGUAGE"), &vLine) &&
 383             (vLine != NULL)) {
 384                 accept_language = (StrBuf*) vLine;
 385         }
 386
 387
 388         ReqType = NewStrBuf();
 389         HTTPVersion = NewStrBuf();
 390         StrBufExtract_token(HTTPVersion, ReqLine, 2, ' ');
 391         StrBufExtract_token(ReqType, ReqLine, 0, ' ');
 392         StrBufCutLeft(ReqLine, StrLength(ReqType) + 1);
 393         StrBufCutRight(ReqLine, StrLength(HTTPVersion) + 1);
 394
 395         /*
 396          * If the request is prefixed by "/webcit" then chop that off.  This
 397          * allows a front end web server to forward all /webcit requests to us
 398          * while still using the same web server port for other things.
 399          */
 400         if ( (StrLength(ReqLine) >= 8) && (strstr(ChrPtr(ReqLine), "/webcit/")) ) {
 401                 StrBufCutLeft(ReqLine, 7);
 402         }
 403
 404         /* Begin parsing the request. */
 405 #ifdef TECH_PREVIEW
 406         if ((strncmp(ChrPtr(ReqLine), "/sslg", 5) != 0) &&
 407             (strncmp(ChrPtr(ReqLine), "/static/", 8) != 0) &&
 408             (strncmp(ChrPtr(ReqLine), "/tiny_mce/", 10) != 0) &&
 409             (strncmp(ChrPtr(ReqLine), "/wholist_section", 16) != 0) &&
 410             (strstr(ChrPtr(ReqLine), "wholist_section") == NULL)) {
 411 #endif
 412                 lprintf(5, "HTTP: %s %s %s\n", ChrPtr(ReqType), ChrPtr(ReqLine), ChrPtr(HTTPVersion));
 413 #ifdef TECH_PREVIEW
 414         }
 415 #endif
 416
 417         /** Check for bogus requests */
 418         if ((StrLength(HTTPVersion) == 0) ||
 419             (StrLength(ReqType) == 0) ||
 420             is_bogus(ReqLine)) {
 421                 StrBufPlain(ReqLine, HKEY("/404 HTTP/1.1"));
 422                 StrBufPlain(ReqType, HKEY("GET"));
 423         }
 424         FreeStrBuf(&HTTPVersion);
 425
 426         /**
 427          * While we're at it, gracefully handle requests for the
 428          * robots.txt and favicon.ico files.
 429          */
 430         if (!strncasecmp(ChrPtr(ReqLine), "/robots.txt", 11)) {
 431                 StrBufPlain(ReqLine,
 432                             HKEY("/static/robots.txt"
 433                                  "?force_close_session=yes HTTP/1.1"));
 434                 StrBufPlain(ReqType, HKEY("GET"));
 435         }
 436         else if (!strncasecmp(ChrPtr(ReqLine), "/favicon.ico", 12)) {
 437                 StrBufPlain(ReqLine, HKEY("/static/favicon.ico"));
 438                 StrBufPlain(ReqType, HKEY("GET"));
 439         }
 440
 441         /**
 442          * These are the URL's which may be executed without a
 443          * session cookie already set.  If it's not one of these,
 444          * force the session to close because cookies are
 445          * probably disabled on the client browser.
 446          */
 447         else if ( (StrLength(ReqLine) > 1 )
 448                 && (strncasecmp(ChrPtr(ReqLine), "/listsub", 8))
 449                 && (strncasecmp(ChrPtr(ReqLine), "/freebusy", 9))
 450                 && (strncasecmp(ChrPtr(ReqLine), "/do_logout", 10))
 451                 && (strncasecmp(ChrPtr(ReqLine), "/groupdav", 9))
 452                 && (strncasecmp(ChrPtr(ReqLine), "/static", 7))
 453                 && (strncasecmp(ChrPtr(ReqLine), "/rss", 4))
 454                 && (strncasecmp(ChrPtr(ReqLine), "/404", 4))
 455                 && (got_cookie == 0)) {
 456                 StrBufPlain(ReqLine,
 457                             HKEY("/static/nocookies.html"
 458                                  "?force_close_session=yes"));
 459         }
 460
 461         /**
 462          * See if there's an existing session open with the desired ID or user/pass
 463          */
 464         TheSession = NULL;
 465
 466         if (TheSession == NULL) {
 467                 pthread_mutex_lock(&SessionListMutex);
 468                 for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
 469
 470                         /** If HTTP-AUTH, look for a session with matching credentials */
 471                         if ( (!IsEmptyStr(httpauth_user))
 472                              &&(!strcasecmp(ChrPtr(sptr->httpauth_user), httpauth_user))
 473                              &&(!strcasecmp(ChrPtr(sptr->httpauth_pass), httpauth_pass)) ) {
 474                                 TheSession = sptr;
 475                         }
 476
 477                         /** If cookie-session, look for a session with matching session ID */
 478                         if ( (desired_session != 0) && (sptr->wc_session == desired_session)) {
 479                                 TheSession = sptr;
 480                         }
 481
 482                 }
 483                 pthread_mutex_unlock(&SessionListMutex);
 484         }
 485
 486         /**
 487          * Create a new session if we have to
 488          */
 489         if (TheSession == NULL) {
 490                 lprintf(3, "Creating a new session\n");
 491                 TheSession = (wcsession *)
 492                         malloc(sizeof(wcsession));
 493                 memset(TheSession, 0, sizeof(wcsession));
 494                 TheSession->serv_sock = (-1);
 495                 TheSession->chat_sock = (-1);
 496
 497                 /* If we're recreating a session that expired, it's best to give it the same
 498                  * session number that it had before.  The client browser ought to pick up
 499                  * the new session number and start using it, but in some rare situations it
 500                  * doesn't, and that's a Bad Thing because it causes lots of spurious sessions
 501                  * to get created.
 502                  */
 503                 if (desired_session == 0) {
 504                         TheSession->wc_session = GenerateSessionID();
 505                 }
 506                 else {
 507                         TheSession->wc_session = desired_session;
 508                 }
 509
 510                 if (TheSession->httpauth_user != NULL){
 511                         FlushStrBuf(TheSession->httpauth_user);
 512                         StrBufAppendBufPlain(TheSession->httpauth_user, httpauth_user, -1, 0);
 513                 }
 514                 else TheSession->httpauth_user = NewStrBufPlain(httpauth_user, -1);
 515                 if (TheSession->httpauth_user != NULL){
 516                         FlushStrBuf(TheSession->httpauth_pass);
 517                         StrBufAppendBufPlain(TheSession->httpauth_pass, httpauth_user, -1, 0);
 518                 }
 519                 else TheSession->httpauth_pass = NewStrBufPlain(httpauth_user, -1);
 520
 521                 TheSession->CLineBuf = NewStrBuf();
 522                 TheSession->hash_prefs = NewHash(1,NULL);       /* Get a hash table for the user preferences */
 523                 pthread_mutex_init(&TheSession->SessionMutex, NULL);
 524                 pthread_mutex_lock(&SessionListMutex);
 525                 TheSession->nonce = rand();
 526                 TheSession->next = SessionList;
 527                 TheSession->is_mobile = -1;
 528                 SessionList = TheSession;
 529                 pthread_mutex_unlock(&SessionListMutex);
 530                 session_is_new = 1;
 531         }
 532
 533         /*
 534          * A future improvement might be to check the session integrity
 535          * at this point before continuing.
 536          */
 537
 538         /*
 539          * Bind to the session and perform the transaction
 540          */
 541         pthread_mutex_lock(&TheSession->SessionMutex);          /* bind */
 542         pthread_setspecific(MyConKey, (void *)TheSession);
 543
 544         TheSession->urlstrings = NewHash(1,NULL);
 545         TheSession->vars = NewHash(1,NULL);
 546         TheSession->http_sock = *sock;
 547         TheSession->lastreq = time(NULL);                       /* log */
 548         TheSession->gzip_ok = gzip_ok;
 549 #ifdef ENABLE_NLS
 550         if (session_is_new) {
 551                 httplang_to_locale(accept_language);
 552         }
 553         go_selected_language();                                 /* set locale */
 554 #endif
 555         session_loop(HTTPHeaders, ReqLine, ReqType, Buf);                               /* do transaction */
 556 #ifdef ENABLE_NLS
 557         stop_selected_language();                               /* unset locale */
 558 #endif
 559         DeleteHash(&TheSession->summ);
 560         DeleteHash(&TheSession->urlstrings);
 561         DeleteHash(&TheSession->vars);
 562         FreeStrBuf(&TheSession->WBuf);
 563         FreeStrBuf(&TheSession->HBuf);
 564
 565
 566         pthread_mutex_unlock(&TheSession->SessionMutex);        /* unbind */
 567
 568         /* Free the request buffer */
 569         DeleteHash(&HTTPHeaders);
 570         FreeStrBuf(&ReqLine);
 571         FreeStrBuf(&ReqType);
 572         FreeStrBuf(&Buf);
 573         /*
 574          * Free up any session-local substitution variables which
 575          * were set during this transaction
 576          */
 577
 578
 579 }
 580
 581 void tmplput_nonce(StrBuf *Target, WCTemplputParams *TP)
 582 {
 583         wcsession *WCC = WC;
 584         StrBufAppendPrintf(Target, "%ld",
 585                            (WCC != NULL)? WCC->nonce:0);
 586 }
 587
 588 void tmplput_current_user(StrBuf *Target, WCTemplputParams *TP)
 589 {
 590         StrBufAppendTemplate(Target, TP, WC->wc_fullname, 0);
 591 }
 592
 593 void tmplput_current_room(StrBuf *Target, WCTemplputParams *TP)
 594 {
 595         StrBufAppendTemplate(Target, TP, WC->wc_roomname, 0);
 596 }
 597
 598
 599
 600 void
 601 InitModule_CONTEXT
 602 (void)
 603 {
 604         RegisterNamespace("CURRENT_USER", 0, 1, tmplput_current_user, CTX_NONE);
 605         RegisterNamespace("CURRENT_ROOM", 0, 1, tmplput_current_room, CTX_NONE);
 606         RegisterNamespace("NONCE", 0, 0, tmplput_nonce, 0);
 607 }