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)->IconBarSetttings));
  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         free((*sessions_to_kill));
  47         (*sessions_to_kill) = NULL;
  48 }
  49
  50 void shutdown_sessions(void)
  51 {
  52         wcsession *sptr;
  53
  54         for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
  55                         sptr->killthis = 1;
  56         }
  57 }
  58
  59 void do_housekeeping(void)
  60 {
  61         wcsession *sptr, *ss;
  62         wcsession *sessions_to_kill = NULL;
  63         int num_sessions = 0;
  64         static int num_threads = MIN_WORKER_THREADS;
  65
  66         /**
  67          * Lock the session list, moving any candidates for euthanasia into
  68          * a separate list.
  69          */
  70         pthread_mutex_lock(&SessionListMutex);
  71         num_sessions = 0;
  72         for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
  73                 ++num_sessions;
  74
  75                 /** Kill idle sessions */
  76                 if ((time(NULL) - (sptr->lastreq)) >
  77                    (time_t) WEBCIT_TIMEOUT) {
  78                         sptr->killthis = 1;
  79                 }
  80
  81                 /** Remove sessions flagged for kill */
  82                 if (sptr->killthis) {
  83
  84                         /** remove session from linked list */
  85                         if (sptr == SessionList) {
  86                                 SessionList = SessionList->next;
  87                         }
  88                         else for (ss=SessionList;ss!=NULL;ss=ss->next) {
  89                                 if (ss->next == sptr) {
  90                                         ss->next = ss->next->next;
  91                                 }
  92                         }
  93
  94                         sptr->next = sessions_to_kill;
  95                         sessions_to_kill = sptr;
  96                 }
  97         }
  98         pthread_mutex_unlock(&SessionListMutex);
  99
 100         /**
 101          * Now free up and destroy the culled sessions.
 102          */
 103         while (sessions_to_kill != NULL) {
 104                 lprintf(3, "Destroying session %d\n", sessions_to_kill->wc_session);
 105                 pthread_mutex_lock(&sessions_to_kill->SessionMutex);
 106                 pthread_mutex_unlock(&sessions_to_kill->SessionMutex);
 107                 sptr = sessions_to_kill->next;
 108
 109                 DestroySession(&sessions_to_kill);
 110                 sessions_to_kill = sptr;
 111                 --num_sessions;
 112         }
 113
 114         /**
 115          * If there are more sessions than threads, then we should spawn
 116          * more threads ... up to a predefined maximum.
 117          */
 118         while ( (num_sessions > num_threads)
 119               && (num_threads <= MAX_WORKER_THREADS) ) {
 120                 spawn_another_worker_thread();
 121                 ++num_threads;
 122                 lprintf(3, "There are %d sessions and %d threads active.\n",
 123                         num_sessions, num_threads);
 124         }
 125 }
 126
 127
 128 /**
 129  * \brief Wake up occasionally and clean house
 130  */
 131 void housekeeping_loop(void)
 132 {
 133         while (1) {
 134                 sleeeeeeeeeep(HOUSEKEEPING);
 135                 do_housekeeping();
 136         }
 137 }
 138
 139
 140 /**
 141  * \brief Create a Session id
 142  * Generate a unique WebCit session ID (which is not the same thing as the
 143  * Citadel session ID).
 144  *
 145  * \todo FIXME ... ensure that session number is truly unique
 146  *
 147  */
 148 int GenerateSessionID(void)
 149 {
 150         static int seq = (-1);
 151
 152         if (seq < 0) {
 153                 seq = (int) time(NULL);
 154         }
 155
 156         return ++seq;
 157 }
 158
 159 /*
 160  * Collapse multiple cookies on one line
 161  */
 162 int ReqGetStrBuf(int *sock, StrBuf *Target, StrBuf *buf)
 163 {
 164
 165         return ClientGetLine(sock, Target, buf);
 166 }
 167
 168
 169
 170 /*
 171  * lingering_close() a`la Apache. see
 172  * http://www.apache.org/docs/misc/fin_wait_2.html for rationale
 173  */
 174 int lingering_close(int fd)
 175 {
 176         char buf[SIZ];
 177         int i;
 178         fd_set set;
 179         struct timeval tv, start;
 180
 181         gettimeofday(&start, NULL);
 182         shutdown(fd, 1);
 183         do {
 184                 do {
 185                         gettimeofday(&tv, NULL);
 186                         tv.tv_sec = SLEEPING - (tv.tv_sec - start.tv_sec);
 187                         tv.tv_usec = start.tv_usec - tv.tv_usec;
 188                         if (tv.tv_usec < 0) {
 189                                 tv.tv_sec--;
 190                                 tv.tv_usec += 1000000;
 191                         }
 192                         FD_ZERO(&set);
 193                         FD_SET(fd, &set);
 194                         i = select(fd + 1, &set, NULL, NULL, &tv);
 195                 } while (i == -1 && errno == EINTR);
 196
 197                 if (i <= 0)
 198                         break;
 199
 200                 i = read(fd, buf, sizeof buf);
 201         } while (i != 0 && (i != -1 || errno == EINTR));
 202
 203         return close(fd);
 204 }
 205
 206
 207
 208 /*
 209  * Look for commonly-found probes of malware such as worms, viruses, trojans, and Microsoft Office.
 210  * Short-circuit these requests so we don't have to send them through the full processing loop.
 211  */
 212 int is_bogus(StrBuf *http_cmd) {
 213         const char *url;
 214         int i, max;
 215         const char *bogus_prefixes[] = {
 216                 "/scripts/root.exe",    /* Worms and trojans and viruses, oh my! */
 217                 "/c/winnt",
 218                 "/MSADC/",
 219                 "/_vti",                /* Broken Microsoft DAV implementation */
 220                 "/MSOffice",            /* Stoopid MSOffice thinks everyone is IIS */
 221                 "/nonexistenshit"       /* Exploit found in the wild January 2009 */
 222         };
 223
 224         url = ChrPtr(http_cmd);
 225         if (IsEmptyStr(url)) return(1);
 226         ++url;
 227
 228         max = sizeof(bogus_prefixes) / sizeof(char *);
 229
 230         for (i=0; i<max; ++i) {
 231                 if (!strncasecmp(url, bogus_prefixes[i], strlen(bogus_prefixes[i]))) {
 232                         return(2);
 233                 }
 234         }
 235
 236         return(0);      /* probably ok */
 237 }
 238
 239
 240 const char *nix(void *vptr) {return ChrPtr( (StrBuf*)vptr);}
 241
 242 /**
 243  * \brief handle one request
 244  * This loop gets called once for every HTTP connection made to WebCit.  At
 245  * this entry point we have an HTTP socket with a browser allegedly on the
 246  * other end, but we have not yet bound to a WebCit session.
 247  *
 248  * The job of this function is to locate the correct session and bind to it,
 249  * or create a session if necessary and bind to it, then run the WebCit
 250  * transaction loop.  Afterwards, we unbind from the session.  When this
 251  * function returns, the worker thread is then free to handle another
 252  * transaction.
 253  * \param sock the socket we will put our answer to
 254  */
 255 void context_loop(int *sock)
 256 {
 257         const char *buf;
 258         int desired_session = 0;
 259         int got_cookie = 0;
 260         int gzip_ok = 0;
 261         wcsession *TheSession, *sptr;
 262         char httpauth_string[1024];
 263         char httpauth_user[1024];
 264         char httpauth_pass[1024];
 265         char *ptr = NULL;
 266         int session_is_new = 0;
 267         int nLine = 0;
 268         int LineLen;
 269         void *vLine;
 270         StrBuf *Buf, *Line, *LastLine, *HeaderName, *ReqLine, *ReqType, *HTTPVersion;
 271         StrBuf *accept_language = NULL;
 272         const char *pch, *pchs, *pche;
 273         HashList *HTTPHeaders;
 274
 275         strcpy(httpauth_string, "");
 276         strcpy(httpauth_user, DEFAULT_HTTPAUTH_USER);
 277         strcpy(httpauth_pass, DEFAULT_HTTPAUTH_PASS);
 278
 279         /**
 280          * Find out what it is that the web browser is asking for
 281          */
 282         HeaderName = NewStrBuf();
 283         Buf = NewStrBuf();
 284         LastLine = NULL;
 285         HTTPHeaders = NewHash(1, NULL);
 286         /**
 287          * Read in the request
 288          */
 289         do {
 290                 nLine ++;
 291                 Line = NewStrBuf();
 292                 if (ReqGetStrBuf(sock, Line, Buf) < 0) return;
 293
 294                 LineLen = StrLength(Line);
 295
 296                 if (nLine == 1) {
 297                         ReqLine = Line;
 298                         continue;
 299                 }
 300                 if (LineLen == 0) {
 301                         FreeStrBuf(&Line);
 302                         continue;
 303                 }
 304
 305                 /** Do we need to Unfold? */
 306                 if ((LastLine != NULL) &&
 307                     (isspace(*ChrPtr(Line)))) {
 308                         pch = pchs = ChrPtr(Line);
 309                         pche = pchs + StrLength(Line);
 310                         while (isspace(*pch) && (pch < pche))
 311                                 pch ++;
 312                         StrBufCutLeft(Line, pch - pchs);
 313                         StrBufAppendBuf(LastLine, Line, 0);
 314                         FreeStrBuf(&Line);
 315                         continue;
 316                 }
 317
 318                 StrBufExtract_token(HeaderName, Line, 0, ':');
 319                 /*/// TODO: filter bad chars! */
 320
 321                 pchs = ChrPtr(Line);
 322                 pch = pchs + StrLength(HeaderName) + 1;
 323                 pche = pchs + StrLength(Line);
 324                 while (isspace(*pch) && (pch < pche))
 325                         pch ++;
 326                 StrBufCutLeft(Line, pch - pchs);
 327
 328                 StrBufUpCase(HeaderName);
 329                 Put(HTTPHeaders, SKEY(HeaderName), Line, HFreeStrBuf);
 330                 LastLine = Line;
 331         } while (LineLen > 0);
 332         FreeStrBuf(&HeaderName);
 333
 334 /*///   dbg_PrintHash(HTTPHeaders, nix, NULL); */
 335
 336
 337         /**
 338          * Can we compress?
 339          */
 340         if (GetHash(HTTPHeaders, HKEY("ACCEPT-ENCODING"), &vLine) &&
 341             (vLine != NULL)) {
 342                 buf = ChrPtr((StrBuf*)vLine);
 343                 if (strstr(&buf[16], "gzip")) {
 344                         gzip_ok = 1;
 345                 }
 346         }
 347
 348         /**
 349          * Browser-based sessions use cookies for session
 350
 351 authentication
 352          */
 353         if (GetHash(HTTPHeaders, HKEY("COOKIE"), &vLine) &&
 354             (vLine != NULL)) {
 355                 cookie_to_stuff(vLine, &desired_session,
 356                                 NULL, 0, NULL, 0, NULL, 0);
 357                 got_cookie = 1;
 358         }
 359
 360         /**
 361          * GroupDAV-based sessions use HTTP authentication
 362          */
 363         if (GetHash(HTTPHeaders, HKEY("AUTHORIZATION"), &vLine) &&
 364             (vLine != NULL)) {
 365                 Line = (StrBuf*)vLine;
 366                 if (strncasecmp(ChrPtr(Line), "Basic", 5) == 0) {
 367                         StrBufCutLeft(Line, 6);
 368                         CtdlDecodeBase64(httpauth_string, ChrPtr(Line), StrLength(Line));
 369                         extract_token(httpauth_user, httpauth_string, 0, ':', sizeof httpauth_user);
 370                         extract_token(httpauth_pass, httpauth_string, 1, ':', sizeof httpauth_pass);
 371                 }
 372                 else
 373                         lprintf(1, "Authentication scheme not supported! [%s]\n", ChrPtr(Line));
 374         }
 375
 376         if (GetHash(HTTPHeaders, HKEY("IF-MODIFIED-SINCE"), &vLine) &&
 377             (vLine != NULL)) {
 378                 if_modified_since = httpdate_to_timestamp((StrBuf*)vLine);
 379         }
 380
 381         if (GetHash(HTTPHeaders, HKEY("ACCEPT-LANGUAGE"), &vLine) &&
 382             (vLine != NULL)) {
 383                 accept_language = (StrBuf*) vLine;
 384         }
 385
 386
 387         /**
 388          * If the request is prefixed by "/webcit" then chop that off.  This
 389          * allows a front end web server to forward all /webcit requests to us
 390          * while still using the same web server port for other things.
 391          */
 392
 393         ReqType = NewStrBuf();
 394         HTTPVersion = NewStrBuf();
 395         StrBufExtract_token(HTTPVersion, ReqLine, 2, ' ');
 396         StrBufExtract_token(ReqType, ReqLine, 0, ' ');
 397         StrBufCutLeft(ReqLine, StrLength(ReqType) + 1);
 398         StrBufCutRight(ReqLine, StrLength(HTTPVersion) + 1);
 399
 400         if ((follow_xff == 1) && (StrLength(ReqLine) >= 8) &&
 401             (ptr = strstr(ChrPtr(ReqLine), "/webcit/"), /*< Handle "/webcit/" */
 402              (ptr != NULL))) {
 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(sptr->httpauth_user, httpauth_user))
 475                            &&(!strcasecmp(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                 strcpy(TheSession->httpauth_user, httpauth_user);
 513                 strcpy(TheSession->httpauth_pass, httpauth_pass);
 514                 TheSession->hash_prefs = NewHash(1,NULL);       /* Get a hash table for the user preferences */
 515                 pthread_mutex_init(&TheSession->SessionMutex, NULL);
 516                 pthread_mutex_lock(&SessionListMutex);
 517                 TheSession->urlstrings = NULL;
 518                 TheSession->vars = NULL;
 519                 TheSession->nonce = rand();
 520                 TheSession->WBuf = NULL;
 521                 TheSession->CLineBuf = NewStrBuf();
 522                 TheSession->next = SessionList;
 523                 TheSession->is_mobile = -1;
 524                 SessionList = TheSession;
 525                 pthread_mutex_unlock(&SessionListMutex);
 526                 session_is_new = 1;
 527         }
 528
 529         /*
 530          * A future improvement might be to check the session integrity
 531          * at this point before continuing.
 532          */
 533
 534         /*
 535          * Bind to the session and perform the transaction
 536          */
 537         pthread_mutex_lock(&TheSession->SessionMutex);          /* bind */
 538         pthread_setspecific(MyConKey, (void *)TheSession);
 539
 540         TheSession->urlstrings = NewHash(1,NULL);
 541         TheSession->vars = NewHash(1,NULL);
 542         TheSession->http_sock = *sock;
 543         TheSession->lastreq = time(NULL);                       /* log */
 544         TheSession->gzip_ok = gzip_ok;
 545 #ifdef ENABLE_NLS
 546         if (session_is_new) {
 547                 httplang_to_locale(accept_language);
 548         }
 549         go_selected_language();                                 /* set locale */
 550 #endif
 551         session_loop(HTTPHeaders, ReqLine, ReqType, Buf);                               /* do transaction */
 552 #ifdef ENABLE_NLS
 553         stop_selected_language();                               /* unset locale */
 554 #endif
 555         DeleteHash(&TheSession->summ);
 556         DeleteHash(&TheSession->urlstrings);
 557         DeleteHash(&TheSession->vars);
 558         FreeStrBuf(&TheSession->WBuf);
 559         FreeStrBuf(&TheSession->HBuf);
 560
 561
 562         pthread_mutex_unlock(&TheSession->SessionMutex);        /* unbind */
 563
 564         /* Free the request buffer */
 565         DeleteHash(&HTTPHeaders);
 566         FreeStrBuf(&ReqLine);
 567         FreeStrBuf(&ReqType);
 568         FreeStrBuf(&Buf);
 569         /*
 570          * Free up any session-local substitution variables which
 571          * were set during this transaction
 572          */
 573
 574
 575 }
 576
 577 void tmpl_nonce(StrBuf *Target, int nArgs, WCTemplateToken *Tokens, void *Context, int ContextType)
 578 {
 579         wcsession *WCC = WC;
 580         StrBufAppendPrintf(Target, "%ld",
 581                            (WCC != NULL)? WCC->nonce:0);
 582 }
 583
 584 void
 585 InitModule_CONTEXT
 586 (void)
 587 {
 588         RegisterNamespace("NONCE", 0, 0, tmpl_nonce, 0);
 589 }