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)->UrlFragment4));
  46         FreeStrBuf(&((*sessions_to_kill)->WBuf));
  47         FreeStrBuf(&((*sessions_to_kill)->HBuf));
  48         FreeStrBuf(&((*sessions_to_kill)->CLineBuf));
  49         FreeStrBuf(&((*sessions_to_kill)->wc_username));
  50         FreeStrBuf(&((*sessions_to_kill)->wc_fullname));
  51         FreeStrBuf(&((*sessions_to_kill)->wc_password));
  52         FreeStrBuf(&((*sessions_to_kill)->wc_roomname));
  53         FreeStrBuf(&((*sessions_to_kill)->httpauth_user));
  54         FreeStrBuf(&((*sessions_to_kill)->httpauth_pass));
  55         free((*sessions_to_kill));
  56         (*sessions_to_kill) = NULL;
  57 }
  58
  59 void shutdown_sessions(void)
  60 {
  61         wcsession *sptr;
  62
  63         for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
  64                         sptr->killthis = 1;
  65         }
  66 }
  67
  68 void do_housekeeping(void)
  69 {
  70         wcsession *sptr, *ss;
  71         wcsession *sessions_to_kill = NULL;
  72         int num_sessions = 0;
  73         static int num_threads = MIN_WORKER_THREADS;
  74
  75         /**
  76          * Lock the session list, moving any candidates for euthanasia into
  77          * a separate list.
  78          */
  79         pthread_mutex_lock(&SessionListMutex);
  80         num_sessions = 0;
  81         for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
  82                 ++num_sessions;
  83
  84                 /** Kill idle sessions */
  85                 if ((time(NULL) - (sptr->lastreq)) >
  86                    (time_t) WEBCIT_TIMEOUT) {
  87                         sptr->killthis = 1;
  88                 }
  89
  90                 /** Remove sessions flagged for kill */
  91                 if (sptr->killthis) {
  92
  93                         /** remove session from linked list */
  94                         if (sptr == SessionList) {
  95                                 SessionList = SessionList->next;
  96                         }
  97                         else for (ss=SessionList;ss!=NULL;ss=ss->next) {
  98                                 if (ss->next == sptr) {
  99                                         ss->next = ss->next->next;
 100                                 }
 101                         }
 102
 103                         sptr->next = sessions_to_kill;
 104                         sessions_to_kill = sptr;
 105                 }
 106         }
 107         pthread_mutex_unlock(&SessionListMutex);
 108
 109         /**
 110          * Now free up and destroy the culled sessions.
 111          */
 112         while (sessions_to_kill != NULL) {
 113                 lprintf(3, "Destroying session %d\n", sessions_to_kill->wc_session);
 114                 pthread_mutex_lock(&sessions_to_kill->SessionMutex);
 115                 pthread_mutex_unlock(&sessions_to_kill->SessionMutex);
 116                 sptr = sessions_to_kill->next;
 117
 118                 DestroySession(&sessions_to_kill);
 119                 sessions_to_kill = sptr;
 120                 --num_sessions;
 121         }
 122
 123         /**
 124          * If there are more sessions than threads, then we should spawn
 125          * more threads ... up to a predefined maximum.
 126          */
 127         while ( (num_sessions > num_threads)
 128               && (num_threads <= MAX_WORKER_THREADS) ) {
 129                 spawn_another_worker_thread();
 130                 ++num_threads;
 131                 lprintf(3, "There are %d sessions and %d threads active.\n",
 132                         num_sessions, num_threads);
 133         }
 134 }
 135
 136
 137 /*
 138  * Wake up occasionally and clean house
 139  */
 140 void housekeeping_loop(void)
 141 {
 142         while (1) {
 143                 sleeeeeeeeeep(HOUSEKEEPING);
 144                 do_housekeeping();
 145         }
 146 }
 147
 148
 149 /*
 150  * Create a Session id
 151  * Generate a unique WebCit session ID (which is not the same thing as the
 152  * Citadel session ID).
 153  */
 154 int GenerateSessionID(void)
 155 {
 156         static int seq = (-1);
 157
 158         if (seq < 0) {
 159                 seq = (int) time(NULL);
 160         }
 161
 162         return ++seq;
 163 }
 164
 165
 166 /*
 167  * lingering_close() a`la Apache. see
 168  * http://www.apache.org/docs/misc/fin_wait_2.html for rationale
 169  */
 170 int lingering_close(int fd)
 171 {
 172         char buf[SIZ];
 173         int i;
 174         fd_set set;
 175         struct timeval tv, start;
 176
 177         gettimeofday(&start, NULL);
 178         shutdown(fd, 1);
 179         do {
 180                 do {
 181                         gettimeofday(&tv, NULL);
 182                         tv.tv_sec = SLEEPING - (tv.tv_sec - start.tv_sec);
 183                         tv.tv_usec = start.tv_usec - tv.tv_usec;
 184                         if (tv.tv_usec < 0) {
 185                                 tv.tv_sec--;
 186                                 tv.tv_usec += 1000000;
 187                         }
 188                         FD_ZERO(&set);
 189                         FD_SET(fd, &set);
 190                         i = select(fd + 1, &set, NULL, NULL, &tv);
 191                 } while (i == -1 && errno == EINTR);
 192
 193                 if (i <= 0)
 194                         break;
 195
 196                 i = read(fd, buf, sizeof buf);
 197         } while (i != 0 && (i != -1 || errno == EINTR));
 198
 199         return close(fd);
 200 }
 201
 202
 203
 204 /*
 205  * Look for commonly-found probes of malware such as worms, viruses, trojans, and Microsoft Office.
 206  * Short-circuit these requests so we don't have to send them through the full processing loop.
 207  */
 208 int is_bogus(StrBuf *http_cmd) {
 209         const char *url;
 210         int i, max;
 211         const char *bogus_prefixes[] = {
 212                 "/scripts/root.exe",    /* Worms and trojans and viruses, oh my! */
 213                 "/c/winnt",
 214                 "/MSADC/",
 215                 "/_vti",                /* Broken Microsoft DAV implementation */
 216                 "/MSOffice",            /* Stoopid MSOffice thinks everyone is IIS */
 217                 "/nonexistenshit"       /* Exploit found in the wild January 2009 */
 218         };
 219
 220         url = ChrPtr(http_cmd);
 221         if (IsEmptyStr(url)) return(1);
 222         ++url;
 223
 224         max = sizeof(bogus_prefixes) / sizeof(char *);
 225
 226         for (i=0; i<max; ++i) {
 227                 if (!strncasecmp(url, bogus_prefixes[i], strlen(bogus_prefixes[i]))) {
 228                         return(2);
 229                 }
 230         }
 231
 232         return(0);      /* probably ok */
 233 }
 234
 235
 236 const char *nix(void *vptr) {return ChrPtr( (StrBuf*)vptr);}
 237
 238 /*
 239  * handle one request
 240  *
 241  * This loop gets called once for every HTTP connection made to WebCit.  At
 242  * this entry point we have an HTTP socket with a browser allegedly on the
 243  * other end, but we have not yet bound to a WebCit session.
 244  *
 245  * The job of this function is to locate the correct session and bind to it,
 246  * or create a session if necessary and bind to it, then run the WebCit
 247  * transaction loop.  Afterwards, we unbind from the session.  When this
 248  * function returns, the worker thread is then free to handle another
 249  * transaction.
 250  */
 251 void context_loop(int *sock)
 252 {
 253         const char *Pos = NULL;
 254         const char *buf;
 255         int desired_session = 0;
 256         int got_cookie = 0;
 257         int gzip_ok = 0;
 258         wcsession *TheSession, *sptr;
 259         char httpauth_string[1024];
 260         char httpauth_user[1024];
 261         char httpauth_pass[1024];
 262         int session_is_new = 0;
 263         int nLine = 0;
 264         int LineLen;
 265         void *vLine;
 266         StrBuf *Buf, *Line, *LastLine, *HeaderName, *ReqLine, *ReqType, *HTTPVersion;
 267         StrBuf *accept_language = NULL;
 268         const char *pch, *pchs, *pche;
 269         HashList *HTTPHeaders;
 270
 271         strcpy(httpauth_string, "");
 272         strcpy(httpauth_user, DEFAULT_HTTPAUTH_USER);
 273         strcpy(httpauth_pass, DEFAULT_HTTPAUTH_PASS);
 274
 275         /*
 276          * Find out what it is that the web browser is asking for
 277          */
 278         HeaderName = NewStrBuf();
 279         Buf = NewStrBuf();
 280         LastLine = NULL;
 281         HTTPHeaders = NewHash(1, NULL);
 282
 283         /*
 284          * Read in the request
 285          */
 286         do {
 287                 nLine ++;
 288                 Line = NewStrBuf();
 289
 290
 291                 if (ClientGetLine(sock, Line, Buf, &Pos) < 0) return;
 292
 293                 LineLen = StrLength(Line);
 294
 295                 if (nLine == 1) {
 296                         ReqLine = Line;
 297                         continue;
 298                 }
 299                 if (LineLen == 0) {
 300                         FreeStrBuf(&Line);
 301                         continue;
 302                 }
 303
 304                 /* Do we need to Unfold? */
 305                 if ((LastLine != NULL) &&
 306                     (isspace(*ChrPtr(Line)))) {
 307                         pch = pchs = ChrPtr(Line);
 308                         pche = pchs + StrLength(Line);
 309                         while (isspace(*pch) && (pch < pche))
 310                                 pch ++;
 311                         StrBufCutLeft(Line, pch - pchs);
 312                         StrBufAppendBuf(LastLine, Line, 0);
 313                         FreeStrBuf(&Line);
 314                         continue;
 315                 }
 316
 317                 StrBufSanitizeAscii(Line, '§');
 318                 StrBufExtract_token(HeaderName, Line, 0, ':');
 319
 320                 pchs = ChrPtr(Line);
 321                 pch = pchs + StrLength(HeaderName) + 1;
 322                 pche = pchs + StrLength(Line);
 323                 while (isspace(*pch) && (pch < pche))
 324                         pch ++;
 325                 StrBufCutLeft(Line, pch - pchs);
 326
 327                 StrBufUpCase(HeaderName);
 328                 Put(HTTPHeaders, SKEY(HeaderName), Line, HFreeStrBuf);
 329                 LastLine = Line;
 330         } while (LineLen > 0);
 331         FreeStrBuf(&HeaderName);
 332         /* finish linebuffered fast reading, cut the read part: */
 333         StrBufCutLeft(Buf, Pos - ChrPtr(Buf));
 334
 335         dbg_PrintHash(HTTPHeaders, nix, NULL);
 336
 337
 338         /*
 339          * Can we compress?
 340          */
 341         if (GetHash(HTTPHeaders, HKEY("ACCEPT-ENCODING"), &vLine) &&
 342             (vLine != NULL)) {
 343                 buf = ChrPtr((StrBuf*)vLine);
 344                 if (strstr(&buf[16], "gzip")) {
 345                         gzip_ok = 1;
 346                 }
 347         }
 348
 349         /*
 350          * Browser-based sessions use cookies for session authentication
 351          */
 352         if (GetHash(HTTPHeaders, HKEY("COOKIE"), &vLine) &&
 353             (vLine != NULL)) {
 354                 cookie_to_stuff(vLine, &desired_session,
 355                                 NULL, NULL, NULL);
 356                 got_cookie = 1;
 357         }
 358
 359         /*
 360          * GroupDAV-based sessions use HTTP authentication
 361          */
 362         if (GetHash(HTTPHeaders, HKEY("AUTHORIZATION"), &vLine) &&
 363             (vLine != NULL)) {
 364                 Line = (StrBuf*)vLine;
 365                 if (strncasecmp(ChrPtr(Line), "Basic", 5) == 0) {
 366                         StrBufCutLeft(Line, 6);
 367                         CtdlDecodeBase64(httpauth_string, ChrPtr(Line), StrLength(Line));
 368                         extract_token(httpauth_user, httpauth_string, 0, ':', sizeof httpauth_user);
 369                         extract_token(httpauth_pass, httpauth_string, 1, ':', sizeof httpauth_pass);
 370                 }
 371                 else
 372                         lprintf(1, "Authentication scheme not supported! [%s]\n", ChrPtr(Line));
 373         }
 374
 375         if (GetHash(HTTPHeaders, HKEY("IF-MODIFIED-SINCE"), &vLine) &&
 376             (vLine != NULL)) {
 377                 if_modified_since = httpdate_to_timestamp((StrBuf*)vLine);
 378         }
 379
 380         if (GetHash(HTTPHeaders, HKEY("ACCEPT-LANGUAGE"), &vLine) &&
 381             (vLine != NULL)) {
 382                 accept_language = (StrBuf*) vLine;
 383         }
 384
 385
 386         ReqType = NewStrBuf();
 387         HTTPVersion = NewStrBuf();
 388         StrBufExtract_token(HTTPVersion, ReqLine, 2, ' ');
 389         StrBufExtract_token(ReqType, ReqLine, 0, ' ');
 390         StrBufCutLeft(ReqLine, StrLength(ReqType) + 1);
 391         StrBufCutRight(ReqLine, StrLength(HTTPVersion) + 1);
 392
 393         /*
 394          * If the request is prefixed by "/webcit" then chop that off.  This
 395          * allows a front end web server to forward all /webcit requests to us
 396          * while still using the same web server port for other things.
 397          */
 398         if ( (StrLength(ReqLine) >= 8) && (strstr(ChrPtr(ReqLine), "/webcit/")) ) {
 399                 StrBufCutLeft(ReqLine, 7);
 400         }
 401
 402         /* Begin parsing the request. */
 403 #ifdef TECH_PREVIEW
 404         if ((strncmp(ChrPtr(ReqLine), "/sslg", 5) != 0) &&
 405             (strncmp(ChrPtr(ReqLine), "/static/", 8) != 0) &&
 406             (strncmp(ChrPtr(ReqLine), "/tiny_mce/", 10) != 0) &&
 407             (strncmp(ChrPtr(ReqLine), "/wholist_section", 16) != 0) &&
 408             (strstr(ChrPtr(ReqLine), "wholist_section") == NULL)) {
 409 #endif
 410                 lprintf(5, "HTTP: %s %s %s\n", ChrPtr(ReqType), ChrPtr(ReqLine), ChrPtr(HTTPVersion));
 411 #ifdef TECH_PREVIEW
 412         }
 413 #endif
 414
 415         /** Check for bogus requests */
 416         if ((StrLength(HTTPVersion) == 0) ||
 417             (StrLength(ReqType) == 0) ||
 418             is_bogus(ReqLine)) {
 419                 StrBufPlain(ReqLine, HKEY("/404 HTTP/1.1"));
 420                 StrBufPlain(ReqType, HKEY("GET"));
 421         }
 422         FreeStrBuf(&HTTPVersion);
 423
 424         /**
 425          * While we're at it, gracefully handle requests for the
 426          * robots.txt and favicon.ico files.
 427          */
 428         if (!strncasecmp(ChrPtr(ReqLine), "/robots.txt", 11)) {
 429                 StrBufPlain(ReqLine,
 430                             HKEY("/static/robots.txt"
 431                                  "?force_close_session=yes HTTP/1.1"));
 432                 StrBufPlain(ReqType, HKEY("GET"));
 433         }
 434         else if (!strncasecmp(ChrPtr(ReqLine), "/favicon.ico", 12)) {
 435                 StrBufPlain(ReqLine, HKEY("/static/favicon.ico"));
 436                 StrBufPlain(ReqType, HKEY("GET"));
 437         }
 438
 439         /**
 440          * These are the URL's which may be executed without a
 441          * session cookie already set.  If it's not one of these,
 442          * force the session to close because cookies are
 443          * probably disabled on the client browser.
 444          */
 445         else if ( (StrLength(ReqLine) > 1 )
 446                 && (strncasecmp(ChrPtr(ReqLine), "/listsub", 8))
 447                 && (strncasecmp(ChrPtr(ReqLine), "/freebusy", 9))
 448                 && (strncasecmp(ChrPtr(ReqLine), "/do_logout", 10))
 449                 && (strncasecmp(ChrPtr(ReqLine), "/groupdav", 9))
 450                 && (strncasecmp(ChrPtr(ReqLine), "/static", 7))
 451                 && (strncasecmp(ChrPtr(ReqLine), "/rss", 4))
 452                 && (strncasecmp(ChrPtr(ReqLine), "/404", 4))
 453                 && (got_cookie == 0)) {
 454                 StrBufPlain(ReqLine,
 455                             HKEY("/static/nocookies.html"
 456                                  "?force_close_session=yes"));
 457         }
 458
 459         /**
 460          * See if there's an existing session open with the desired ID or user/pass
 461          */
 462         TheSession = NULL;
 463
 464         if (TheSession == NULL) {
 465                 pthread_mutex_lock(&SessionListMutex);
 466                 for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
 467
 468                         /** If HTTP-AUTH, look for a session with matching credentials */
 469                         if ( (!IsEmptyStr(httpauth_user))
 470                              &&(!strcasecmp(ChrPtr(sptr->httpauth_user), httpauth_user))
 471                              &&(!strcasecmp(ChrPtr(sptr->httpauth_pass), httpauth_pass)) ) {
 472                                 TheSession = sptr;
 473                         }
 474
 475                         /** If cookie-session, look for a session with matching session ID */
 476                         if ( (desired_session != 0) && (sptr->wc_session == desired_session)) {
 477                                 TheSession = sptr;
 478                         }
 479
 480                 }
 481                 pthread_mutex_unlock(&SessionListMutex);
 482         }
 483
 484         /**
 485          * Create a new session if we have to
 486          */
 487         if (TheSession == NULL) {
 488                 lprintf(3, "Creating a new session\n");
 489                 TheSession = (wcsession *)
 490                         malloc(sizeof(wcsession));
 491                 memset(TheSession, 0, sizeof(wcsession));
 492                 TheSession->serv_sock = (-1);
 493                 TheSession->chat_sock = (-1);
 494
 495                 /* If we're recreating a session that expired, it's best to give it the same
 496                  * session number that it had before.  The client browser ought to pick up
 497                  * the new session number and start using it, but in some rare situations it
 498                  * doesn't, and that's a Bad Thing because it causes lots of spurious sessions
 499                  * to get created.
 500                  */
 501                 if (desired_session == 0) {
 502                         TheSession->wc_session = GenerateSessionID();
 503                 }
 504                 else {
 505                         TheSession->wc_session = desired_session;
 506                 }
 507
 508                 if (TheSession->httpauth_user != NULL){
 509                         FlushStrBuf(TheSession->httpauth_user);
 510                         StrBufAppendBufPlain(TheSession->httpauth_user, httpauth_user, -1, 0);
 511                 }
 512                 else TheSession->httpauth_user = NewStrBufPlain(httpauth_user, -1);
 513                 if (TheSession->httpauth_user != NULL){
 514                         FlushStrBuf(TheSession->httpauth_pass);
 515                         StrBufAppendBufPlain(TheSession->httpauth_pass, httpauth_user, -1, 0);
 516                 }
 517                 else TheSession->httpauth_pass = NewStrBufPlain(httpauth_user, -1);
 518
 519                 TheSession->CLineBuf = NewStrBuf();
 520                 TheSession->hash_prefs = NewHash(1,NULL);       /* Get a hash table for the user preferences */
 521                 pthread_mutex_init(&TheSession->SessionMutex, NULL);
 522                 pthread_mutex_lock(&SessionListMutex);
 523                 TheSession->nonce = rand();
 524                 TheSession->next = SessionList;
 525                 TheSession->is_mobile = -1;
 526                 SessionList = TheSession;
 527                 pthread_mutex_unlock(&SessionListMutex);
 528                 session_is_new = 1;
 529         }
 530
 531         /*
 532          * A future improvement might be to check the session integrity
 533          * at this point before continuing.
 534          */
 535
 536         /*
 537          * Bind to the session and perform the transaction
 538          */
 539         pthread_mutex_lock(&TheSession->SessionMutex);          /* bind */
 540         pthread_setspecific(MyConKey, (void *)TheSession);
 541
 542         TheSession->urlstrings = NewHash(1,NULL);
 543         TheSession->vars = NewHash(1,NULL);
 544         TheSession->http_sock = *sock;
 545         TheSession->lastreq = time(NULL);                       /* log */
 546         TheSession->gzip_ok = gzip_ok;
 547 #ifdef ENABLE_NLS
 548         if (session_is_new) {
 549                 httplang_to_locale(accept_language);
 550         }
 551         go_selected_language();                                 /* set locale */
 552 #endif
 553         session_loop(HTTPHeaders, ReqLine, ReqType, Buf);                               /* do transaction */
 554 #ifdef ENABLE_NLS
 555         stop_selected_language();                               /* unset locale */
 556 #endif
 557         DeleteHash(&TheSession->summ);
 558         DeleteHash(&TheSession->urlstrings);
 559         DeleteHash(&TheSession->vars);
 560         FreeStrBuf(&TheSession->WBuf);
 561         FreeStrBuf(&TheSession->HBuf);
 562
 563
 564         pthread_mutex_unlock(&TheSession->SessionMutex);        /* unbind */
 565
 566         /* Free the request buffer */
 567         DeleteHash(&HTTPHeaders);
 568         FreeStrBuf(&ReqLine);
 569         FreeStrBuf(&ReqType);
 570         FreeStrBuf(&Buf);
 571         /*
 572          * Free up any session-local substitution variables which
 573          * were set during this transaction
 574          */
 575
 576
 577 }
 578
 579 void tmplput_nonce(StrBuf *Target, WCTemplputParams *TP)
 580 {
 581         wcsession *WCC = WC;
 582         StrBufAppendPrintf(Target, "%ld",
 583                            (WCC != NULL)? WCC->nonce:0);
 584 }
 585
 586 void tmplput_current_user(StrBuf *Target, WCTemplputParams *TP)
 587 {
 588         StrBufAppendTemplate(Target, TP, WC->wc_fullname, 0);
 589 }
 590
 591 void tmplput_current_room(StrBuf *Target, WCTemplputParams *TP)
 592 {
 593         StrBufAppendTemplate(Target, TP, WC->wc_roomname, 0);
 594 }
 595
 596
 597
 598 void
 599 InitModule_CONTEXT
 600 (void)
 601 {
 602         RegisterNamespace("CURRENT_USER", 0, 1, tmplput_current_user, CTX_NONE);
 603         RegisterNamespace("CURRENT_ROOM", 0, 1, tmplput_current_room, CTX_NONE);
 604         RegisterNamespace("NONCE", 0, 0, tmplput_nonce, 0);
 605 }