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         DeleteServInfo(&((*sessions_to_kill)->serv_info));
  36         DeleteHash(&((*sessions_to_kill)->attachments));
  37         free_march_list((*sessions_to_kill));
  38         DeleteHash(&((*sessions_to_kill)->hash_prefs));
  39         DeleteHash(&((*sessions_to_kill)->IconBarSettings));
  40         DeleteHash(&((*sessions_to_kill)->ServCfg));
  41         FreeStrBuf(&((*sessions_to_kill)->ReadBuf));
  42         FreeStrBuf(&((*sessions_to_kill)->UrlFragment1));
  43         FreeStrBuf(&((*sessions_to_kill)->UrlFragment2));
  44         FreeStrBuf(&((*sessions_to_kill)->UrlFragment3));
  45         FreeStrBuf(&((*sessions_to_kill)->WBuf));
  46         FreeStrBuf(&((*sessions_to_kill)->HBuf));
  47         FreeStrBuf(&((*sessions_to_kill)->CLineBuf));
  48         FreeStrBuf(&((*sessions_to_kill)->wc_username));
  49         FreeStrBuf(&((*sessions_to_kill)->wc_fullname));
  50         FreeStrBuf(&((*sessions_to_kill)->wc_password));
  51         FreeStrBuf(&((*sessions_to_kill)->wc_roomname));
  52         FreeStrBuf(&((*sessions_to_kill)->httpauth_user));
  53         FreeStrBuf(&((*sessions_to_kill)->httpauth_pass));
  54         free((*sessions_to_kill));
  55         (*sessions_to_kill) = NULL;
  56 }
  57
  58 void shutdown_sessions(void)
  59 {
  60         wcsession *sptr;
  61
  62         for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
  63                         sptr->killthis = 1;
  64         }
  65 }
  66
  67 void do_housekeeping(void)
  68 {
  69         wcsession *sptr, *ss;
  70         wcsession *sessions_to_kill = NULL;
  71         int num_sessions = 0;
  72         static int num_threads = MIN_WORKER_THREADS;
  73
  74         /**
  75          * Lock the session list, moving any candidates for euthanasia into
  76          * a separate list.
  77          */
  78         pthread_mutex_lock(&SessionListMutex);
  79         num_sessions = 0;
  80         for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
  81                 ++num_sessions;
  82
  83                 /** Kill idle sessions */
  84                 if ((time(NULL) - (sptr->lastreq)) >
  85                    (time_t) WEBCIT_TIMEOUT) {
  86                         sptr->killthis = 1;
  87                 }
  88
  89                 /** Remove sessions flagged for kill */
  90                 if (sptr->killthis) {
  91
  92                         /** remove session from linked list */
  93                         if (sptr == SessionList) {
  94                                 SessionList = SessionList->next;
  95                         }
  96                         else for (ss=SessionList;ss!=NULL;ss=ss->next) {
  97                                 if (ss->next == sptr) {
  98                                         ss->next = ss->next->next;
  99                                 }
 100                         }
 101
 102                         sptr->next = sessions_to_kill;
 103                         sessions_to_kill = sptr;
 104                 }
 105         }
 106         pthread_mutex_unlock(&SessionListMutex);
 107
 108         /**
 109          * Now free up and destroy the culled sessions.
 110          */
 111         while (sessions_to_kill != NULL) {
 112                 lprintf(3, "Destroying session %d\n", sessions_to_kill->wc_session);
 113                 pthread_mutex_lock(&sessions_to_kill->SessionMutex);
 114                 pthread_mutex_unlock(&sessions_to_kill->SessionMutex);
 115                 sptr = sessions_to_kill->next;
 116
 117                 DestroySession(&sessions_to_kill);
 118                 sessions_to_kill = sptr;
 119                 --num_sessions;
 120         }
 121
 122         /**
 123          * If there are more sessions than threads, then we should spawn
 124          * more threads ... up to a predefined maximum.
 125          */
 126         while ( (num_sessions > num_threads)
 127               && (num_threads <= MAX_WORKER_THREADS) ) {
 128                 spawn_another_worker_thread();
 129                 ++num_threads;
 130                 lprintf(3, "There are %d sessions and %d threads active.\n",
 131                         num_sessions, num_threads);
 132         }
 133 }
 134
 135
 136 /*
 137  * Wake up occasionally and clean house
 138  */
 139 void housekeeping_loop(void)
 140 {
 141         while (1) {
 142                 sleeeeeeeeeep(HOUSEKEEPING);
 143                 do_housekeeping();
 144         }
 145 }
 146
 147
 148 /*
 149  * Create a Session id
 150  * Generate a unique WebCit session ID (which is not the same thing as the
 151  * Citadel session ID).
 152  */
 153 int GenerateSessionID(void)
 154 {
 155         static int seq = (-1);
 156
 157         if (seq < 0) {
 158                 seq = (int) time(NULL);
 159         }
 160
 161         return ++seq;
 162 }
 163
 164 /*
 165  * Collapse multiple cookies on one line
 166  */
 167 int ReqGetStrBuf(int *sock, StrBuf *Target, StrBuf *buf)
 168 {
 169
 170         return ClientGetLine(sock, Target, buf);
 171 }
 172
 173
 174
 175 /*
 176  * lingering_close() a`la Apache. see
 177  * http://www.apache.org/docs/misc/fin_wait_2.html for rationale
 178  */
 179 int lingering_close(int fd)
 180 {
 181         char buf[SIZ];
 182         int i;
 183         fd_set set;
 184         struct timeval tv, start;
 185
 186         gettimeofday(&start, NULL);
 187         shutdown(fd, 1);
 188         do {
 189                 do {
 190                         gettimeofday(&tv, NULL);
 191                         tv.tv_sec = SLEEPING - (tv.tv_sec - start.tv_sec);
 192                         tv.tv_usec = start.tv_usec - tv.tv_usec;
 193                         if (tv.tv_usec < 0) {
 194                                 tv.tv_sec--;
 195                                 tv.tv_usec += 1000000;
 196                         }
 197                         FD_ZERO(&set);
 198                         FD_SET(fd, &set);
 199                         i = select(fd + 1, &set, NULL, NULL, &tv);
 200                 } while (i == -1 && errno == EINTR);
 201
 202                 if (i <= 0)
 203                         break;
 204
 205                 i = read(fd, buf, sizeof buf);
 206         } while (i != 0 && (i != -1 || errno == EINTR));
 207
 208         return close(fd);
 209 }
 210
 211
 212
 213 /*
 214  * Look for commonly-found probes of malware such as worms, viruses, trojans, and Microsoft Office.
 215  * Short-circuit these requests so we don't have to send them through the full processing loop.
 216  */
 217 int is_bogus(StrBuf *http_cmd) {
 218         const char *url;
 219         int i, max;
 220         const char *bogus_prefixes[] = {
 221                 "/scripts/root.exe",    /* Worms and trojans and viruses, oh my! */
 222                 "/c/winnt",
 223                 "/MSADC/",
 224                 "/_vti",                /* Broken Microsoft DAV implementation */
 225                 "/MSOffice",            /* Stoopid MSOffice thinks everyone is IIS */
 226                 "/nonexistenshit"       /* Exploit found in the wild January 2009 */
 227         };
 228
 229         url = ChrPtr(http_cmd);
 230         if (IsEmptyStr(url)) return(1);
 231         ++url;
 232
 233         max = sizeof(bogus_prefixes) / sizeof(char *);
 234
 235         for (i=0; i<max; ++i) {
 236                 if (!strncasecmp(url, bogus_prefixes[i], strlen(bogus_prefixes[i]))) {
 237                         return(2);
 238                 }
 239         }
 240
 241         return(0);      /* probably ok */
 242 }
 243
 244
 245 const char *nix(void *vptr) {return ChrPtr( (StrBuf*)vptr);}
 246
 247 /*
 248  * handle one request
 249  *
 250  * This loop gets called once for every HTTP connection made to WebCit.  At
 251  * this entry point we have an HTTP socket with a browser allegedly on the
 252  * other end, but we have not yet bound to a WebCit session.
 253  *
 254  * The job of this function is to locate the correct session and bind to it,
 255  * or create a session if necessary and bind to it, then run the WebCit
 256  * transaction loop.  Afterwards, we unbind from the session.  When this
 257  * function returns, the worker thread is then free to handle another
 258  * transaction.
 259  */
 260 void context_loop(int *sock)
 261 {
 262         const char *buf;
 263         int desired_session = 0;
 264         int got_cookie = 0;
 265         int gzip_ok = 0;
 266         wcsession *TheSession, *sptr;
 267         char httpauth_string[1024];
 268         char httpauth_user[1024];
 269         char httpauth_pass[1024];
 270         int session_is_new = 0;
 271         int nLine = 0;
 272         int LineLen;
 273         void *vLine;
 274         StrBuf *Buf, *Line, *LastLine, *HeaderName, *ReqLine, *ReqType, *HTTPVersion;
 275         StrBuf *accept_language = NULL;
 276         const char *pch, *pchs, *pche;
 277         HashList *HTTPHeaders;
 278
 279         strcpy(httpauth_string, "");
 280         strcpy(httpauth_user, DEFAULT_HTTPAUTH_USER);
 281         strcpy(httpauth_pass, DEFAULT_HTTPAUTH_PASS);
 282
 283         /*
 284          * Find out what it is that the web browser is asking for
 285          */
 286         HeaderName = NewStrBuf();
 287         Buf = NewStrBuf();
 288         LastLine = NULL;
 289         HTTPHeaders = NewHash(1, NULL);
 290
 291         /*
 292          * Read in the request
 293          */
 294         do {
 295                 nLine ++;
 296                 Line = NewStrBuf();
 297                 if (ReqGetStrBuf(sock, Line, Buf) < 0) return;
 298
 299                 LineLen = StrLength(Line);
 300
 301                 if (nLine == 1) {
 302                         ReqLine = Line;
 303                         continue;
 304                 }
 305                 if (LineLen == 0) {
 306                         FreeStrBuf(&Line);
 307                         continue;
 308                 }
 309
 310                 /* Do we need to Unfold? */
 311                 if ((LastLine != NULL) &&
 312                     (isspace(*ChrPtr(Line)))) {
 313                         pch = pchs = ChrPtr(Line);
 314                         pche = pchs + StrLength(Line);
 315                         while (isspace(*pch) && (pch < pche))
 316                                 pch ++;
 317                         StrBufCutLeft(Line, pch - pchs);
 318                         StrBufAppendBuf(LastLine, Line, 0);
 319                         FreeStrBuf(&Line);
 320                         continue;
 321                 }
 322
 323                 StrBufSanitizeAscii(Line, '§');
 324                 StrBufExtract_token(HeaderName, Line, 0, ':');
 325
 326                 pchs = ChrPtr(Line);
 327                 pch = pchs + StrLength(HeaderName) + 1;
 328                 pche = pchs + StrLength(Line);
 329                 while (isspace(*pch) && (pch < pche))
 330                         pch ++;
 331                 StrBufCutLeft(Line, pch - pchs);
 332
 333                 StrBufUpCase(HeaderName);
 334                 Put(HTTPHeaders, SKEY(HeaderName), Line, HFreeStrBuf);
 335                 LastLine = Line;
 336         } while (LineLen > 0);
 337         FreeStrBuf(&HeaderName);
 338
 339 /*///   dbg_PrintHash(HTTPHeaders, nix, NULL); */
 340
 341
 342         /*
 343          * Can we compress?
 344          */
 345         if (GetHash(HTTPHeaders, HKEY("ACCEPT-ENCODING"), &vLine) &&
 346             (vLine != NULL)) {
 347                 buf = ChrPtr((StrBuf*)vLine);
 348                 if (strstr(&buf[16], "gzip")) {
 349                         gzip_ok = 1;
 350                 }
 351         }
 352
 353         /*
 354          * Browser-based sessions use cookies for session authentication
 355          */
 356         if (GetHash(HTTPHeaders, HKEY("COOKIE"), &vLine) &&
 357             (vLine != NULL)) {
 358                 cookie_to_stuff(vLine, &desired_session,
 359                                 NULL, NULL, NULL);
 360                 got_cookie = 1;
 361         }
 362
 363         /*
 364          * GroupDAV-based sessions use HTTP authentication
 365          */
 366         if (GetHash(HTTPHeaders, HKEY("AUTHORIZATION"), &vLine) &&
 367             (vLine != NULL)) {
 368                 Line = (StrBuf*)vLine;
 369                 if (strncasecmp(ChrPtr(Line), "Basic", 5) == 0) {
 370                         StrBufCutLeft(Line, 6);
 371                         CtdlDecodeBase64(httpauth_string, ChrPtr(Line), StrLength(Line));
 372                         extract_token(httpauth_user, httpauth_string, 0, ':', sizeof httpauth_user);
 373                         extract_token(httpauth_pass, httpauth_string, 1, ':', sizeof httpauth_pass);
 374                 }
 375                 else
 376                         lprintf(1, "Authentication scheme not supported! [%s]\n", ChrPtr(Line));
 377         }
 378
 379         if (GetHash(HTTPHeaders, HKEY("IF-MODIFIED-SINCE"), &vLine) &&
 380             (vLine != NULL)) {
 381                 if_modified_since = httpdate_to_timestamp((StrBuf*)vLine);
 382         }
 383
 384         if (GetHash(HTTPHeaders, HKEY("ACCEPT-LANGUAGE"), &vLine) &&
 385             (vLine != NULL)) {
 386                 accept_language = (StrBuf*) vLine;
 387         }
 388
 389
 390         ReqType = NewStrBuf();
 391         HTTPVersion = NewStrBuf();
 392         StrBufExtract_token(HTTPVersion, ReqLine, 2, ' ');
 393         StrBufExtract_token(ReqType, ReqLine, 0, ' ');
 394         StrBufCutLeft(ReqLine, StrLength(ReqType) + 1);
 395         StrBufCutRight(ReqLine, StrLength(HTTPVersion) + 1);
 396
 397         /*
 398          * If the request is prefixed by "/webcit" then chop that off.  This
 399          * allows a front end web server to forward all /webcit requests to us
 400          * while still using the same web server port for other things.
 401          */
 402         if ( (StrLength(ReqLine) >= 8) && (strstr(ChrPtr(ReqLine), "/webcit/")) ) {
 403                 StrBufCutLeft(ReqLine, 7);
 404         }
 405
 406         /* Begin parsing the request. */
 407 #ifdef TECH_PREVIEW
 408         if ((strncmp(ChrPtr(ReqLine), "/sslg", 5) != 0) &&
 409             (strncmp(ChrPtr(ReqLine), "/static/", 8) != 0) &&
 410             (strncmp(ChrPtr(ReqLine), "/tiny_mce/", 10) != 0) &&
 411             (strncmp(ChrPtr(ReqLine), "/wholist_section", 16) != 0) &&
 412             (strstr(ChrPtr(ReqLine), "wholist_section") == NULL)) {
 413 #endif
 414                 lprintf(5, "HTTP: %s %s %s\n", ChrPtr(ReqType), ChrPtr(ReqLine), ChrPtr(HTTPVersion));
 415 #ifdef TECH_PREVIEW
 416         }
 417 #endif
 418
 419         /** Check for bogus requests */
 420         if ((StrLength(HTTPVersion) == 0) ||
 421             (StrLength(ReqType) == 0) ||
 422             is_bogus(ReqLine)) {
 423                 StrBufPlain(ReqLine, HKEY("/404 HTTP/1.1"));
 424                 StrBufPlain(ReqType, HKEY("GET"));
 425         }
 426         FreeStrBuf(&HTTPVersion);
 427
 428         /**
 429          * While we're at it, gracefully handle requests for the
 430          * robots.txt and favicon.ico files.
 431          */
 432         if (!strncasecmp(ChrPtr(ReqLine), "/robots.txt", 11)) {
 433                 StrBufPlain(ReqLine,
 434                             HKEY("/static/robots.txt"
 435                                  "?force_close_session=yes HTTP/1.1"));
 436                 StrBufPlain(ReqType, HKEY("GET"));
 437         }
 438         else if (!strncasecmp(ChrPtr(ReqLine), "/favicon.ico", 12)) {
 439                 StrBufPlain(ReqLine, HKEY("/static/favicon.ico"));
 440                 StrBufPlain(ReqType, HKEY("GET"));
 441         }
 442
 443         /**
 444          * These are the URL's which may be executed without a
 445          * session cookie already set.  If it's not one of these,
 446          * force the session to close because cookies are
 447          * probably disabled on the client browser.
 448          */
 449         else if ( (StrLength(ReqLine) > 1 )
 450                 && (strncasecmp(ChrPtr(ReqLine), "/listsub", 8))
 451                 && (strncasecmp(ChrPtr(ReqLine), "/freebusy", 9))
 452                 && (strncasecmp(ChrPtr(ReqLine), "/do_logout", 10))
 453                 && (strncasecmp(ChrPtr(ReqLine), "/groupdav", 9))
 454                 && (strncasecmp(ChrPtr(ReqLine), "/static", 7))
 455                 && (strncasecmp(ChrPtr(ReqLine), "/rss", 4))
 456                 && (strncasecmp(ChrPtr(ReqLine), "/404", 4))
 457                 && (got_cookie == 0)) {
 458                 StrBufPlain(ReqLine,
 459                             HKEY("/static/nocookies.html"
 460                                  "?force_close_session=yes"));
 461         }
 462
 463         /**
 464          * See if there's an existing session open with the desired ID or user/pass
 465          */
 466         TheSession = NULL;
 467
 468         if (TheSession == NULL) {
 469                 pthread_mutex_lock(&SessionListMutex);
 470                 for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
 471
 472                         /** If HTTP-AUTH, look for a session with matching credentials */
 473                         if ( (!IsEmptyStr(httpauth_user))
 474                              &&(!strcasecmp(ChrPtr(sptr->httpauth_user), httpauth_user))
 475                              &&(!strcasecmp(ChrPtr(sptr->httpauth_pass), httpauth_pass)) ) {
 476                                 TheSession = sptr;
 477                         }
 478
 479                         /** If cookie-session, look for a session with matching session ID */
 480                         if ( (desired_session != 0) && (sptr->wc_session == desired_session)) {
 481                                 TheSession = sptr;
 482                         }
 483
 484                 }
 485                 pthread_mutex_unlock(&SessionListMutex);
 486         }
 487
 488         /**
 489          * Create a new session if we have to
 490          */
 491         if (TheSession == NULL) {
 492                 lprintf(3, "Creating a new session\n");
 493                 TheSession = (wcsession *)
 494                         malloc(sizeof(wcsession));
 495                 memset(TheSession, 0, sizeof(wcsession));
 496                 TheSession->serv_sock = (-1);
 497                 TheSession->chat_sock = (-1);
 498
 499                 /* If we're recreating a session that expired, it's best to give it the same
 500                  * session number that it had before.  The client browser ought to pick up
 501                  * the new session number and start using it, but in some rare situations it
 502                  * doesn't, and that's a Bad Thing because it causes lots of spurious sessions
 503                  * to get created.
 504                  */
 505                 if (desired_session == 0) {
 506                         TheSession->wc_session = GenerateSessionID();
 507                 }
 508                 else {
 509                         TheSession->wc_session = desired_session;
 510                 }
 511
 512                 if (TheSession->httpauth_user != NULL){
 513                         FlushStrBuf(TheSession->httpauth_user);
 514                         StrBufAppendBufPlain(TheSession->httpauth_user, httpauth_user, -1, 0);
 515                 }
 516                 else TheSession->httpauth_user = NewStrBufPlain(httpauth_user, -1);
 517                 if (TheSession->httpauth_user != NULL){
 518                         FlushStrBuf(TheSession->httpauth_pass);
 519                         StrBufAppendBufPlain(TheSession->httpauth_pass, httpauth_user, -1, 0);
 520                 }
 521                 else TheSession->httpauth_pass = NewStrBufPlain(httpauth_user, -1);
 522
 523                 TheSession->CLineBuf = NewStrBuf();
 524                 TheSession->hash_prefs = NewHash(1,NULL);       /* Get a hash table for the user preferences */
 525                 pthread_mutex_init(&TheSession->SessionMutex, NULL);
 526                 pthread_mutex_lock(&SessionListMutex);
 527                 TheSession->nonce = rand();
 528                 TheSession->next = SessionList;
 529                 TheSession->is_mobile = -1;
 530                 SessionList = TheSession;
 531                 pthread_mutex_unlock(&SessionListMutex);
 532                 session_is_new = 1;
 533         }
 534
 535         /*
 536          * A future improvement might be to check the session integrity
 537          * at this point before continuing.
 538          */
 539
 540         /*
 541          * Bind to the session and perform the transaction
 542          */
 543         pthread_mutex_lock(&TheSession->SessionMutex);          /* bind */
 544         pthread_setspecific(MyConKey, (void *)TheSession);
 545
 546         TheSession->urlstrings = NewHash(1,NULL);
 547         TheSession->vars = NewHash(1,NULL);
 548         TheSession->http_sock = *sock;
 549         TheSession->lastreq = time(NULL);                       /* log */
 550         TheSession->gzip_ok = gzip_ok;
 551 #ifdef ENABLE_NLS
 552         if (session_is_new) {
 553                 httplang_to_locale(accept_language);
 554         }
 555         go_selected_language();                                 /* set locale */
 556 #endif
 557         session_loop(HTTPHeaders, ReqLine, ReqType, Buf);                               /* do transaction */
 558 #ifdef ENABLE_NLS
 559         stop_selected_language();                               /* unset locale */
 560 #endif
 561         DeleteHash(&TheSession->summ);
 562         DeleteHash(&TheSession->urlstrings);
 563         DeleteHash(&TheSession->vars);
 564         FreeStrBuf(&TheSession->WBuf);
 565         FreeStrBuf(&TheSession->HBuf);
 566
 567
 568         pthread_mutex_unlock(&TheSession->SessionMutex);        /* unbind */
 569
 570         /* Free the request buffer */
 571         DeleteHash(&HTTPHeaders);
 572         FreeStrBuf(&ReqLine);
 573         FreeStrBuf(&ReqType);
 574         FreeStrBuf(&Buf);
 575         /*
 576          * Free up any session-local substitution variables which
 577          * were set during this transaction
 578          */
 579
 580
 581 }
 582
 583 void tmplput_nonce(StrBuf *Target, WCTemplputParams *TP)
 584 {
 585         wcsession *WCC = WC;
 586         StrBufAppendPrintf(Target, "%ld",
 587                            (WCC != NULL)? WCC->nonce:0);
 588 }
 589
 590 void tmplput_current_user(StrBuf *Target, WCTemplputParams *TP)
 591 {
 592         StrBufAppendTemplate(Target, TP, WC->wc_fullname, 0);
 593 }
 594
 595 void tmplput_current_room(StrBuf *Target, WCTemplputParams *TP)
 596 {
 597         StrBufAppendTemplate(Target, TP, WC->wc_roomname, 0);
 598 }
 599
 600
 601
 602 void
 603 InitModule_CONTEXT
 604 (void)
 605 {
 606         RegisterNamespace("CURRENT_USER", 0, 1, tmplput_current_user, CTX_NONE);
 607         RegisterNamespace("CURRENT_ROOM", 0, 1, tmplput_current_room, CTX_NONE);
 608         RegisterNamespace("NONCE", 0, 0, tmplput_nonce, 0);
 609 }