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