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  * Collapse multiple cookies on one line
 167  */
 168 int ReqGetStrBuf(int *sock, StrBuf *Target, StrBuf *buf)
 169 {
 170
 171         return ClientGetLine(sock, Target, buf);
 172 }
 173
 174
 175
 176 /*
 177  * lingering_close() a`la Apache. see
 178  * http://www.apache.org/docs/misc/fin_wait_2.html for rationale
 179  */
 180 int lingering_close(int fd)
 181 {
 182         char buf[SIZ];
 183         int i;
 184         fd_set set;
 185         struct timeval tv, start;
 186
 187         gettimeofday(&start, NULL);
 188         shutdown(fd, 1);
 189         do {
 190                 do {
 191                         gettimeofday(&tv, NULL);
 192                         tv.tv_sec = SLEEPING - (tv.tv_sec - start.tv_sec);
 193                         tv.tv_usec = start.tv_usec - tv.tv_usec;
 194                         if (tv.tv_usec < 0) {
 195                                 tv.tv_sec--;
 196                                 tv.tv_usec += 1000000;
 197                         }
 198                         FD_ZERO(&set);
 199                         FD_SET(fd, &set);
 200                         i = select(fd + 1, &set, NULL, NULL, &tv);
 201                 } while (i == -1 && errno == EINTR);
 202
 203                 if (i <= 0)
 204                         break;
 205
 206                 i = read(fd, buf, sizeof buf);
 207         } while (i != 0 && (i != -1 || errno == EINTR));
 208
 209         return close(fd);
 210 }
 211
 212
 213
 214 /*
 215  * Look for commonly-found probes of malware such as worms, viruses, trojans, and Microsoft Office.
 216  * Short-circuit these requests so we don't have to send them through the full processing loop.
 217  */
 218 int is_bogus(StrBuf *http_cmd) {
 219         const char *url;
 220         int i, max;
 221         const char *bogus_prefixes[] = {
 222                 "/scripts/root.exe",    /* Worms and trojans and viruses, oh my! */
 223                 "/c/winnt",
 224                 "/MSADC/",
 225                 "/_vti",                /* Broken Microsoft DAV implementation */
 226                 "/MSOffice",            /* Stoopid MSOffice thinks everyone is IIS */
 227                 "/nonexistenshit"       /* Exploit found in the wild January 2009 */
 228         };
 229
 230         url = ChrPtr(http_cmd);
 231         if (IsEmptyStr(url)) return(1);
 232         ++url;
 233
 234         max = sizeof(bogus_prefixes) / sizeof(char *);
 235
 236         for (i=0; i<max; ++i) {
 237                 if (!strncasecmp(url, bogus_prefixes[i], strlen(bogus_prefixes[i]))) {
 238                         return(2);
 239                 }
 240         }
 241
 242         return(0);      /* probably ok */
 243 }
 244
 245
 246 const char *nix(void *vptr) {return ChrPtr( (StrBuf*)vptr);}
 247
 248 /*
 249  * handle one request
 250  *
 251  * This loop gets called once for every HTTP connection made to WebCit.  At
 252  * this entry point we have an HTTP socket with a browser allegedly on the
 253  * other end, but we have not yet bound to a WebCit session.
 254  *
 255  * The job of this function is to locate the correct session and bind to it,
 256  * or create a session if necessary and bind to it, then run the WebCit
 257  * transaction loop.  Afterwards, we unbind from the session.  When this
 258  * function returns, the worker thread is then free to handle another
 259  * transaction.
 260  */
 261 void context_loop(int *sock)
 262 {
 263         const char *buf;
 264         int desired_session = 0;
 265         int got_cookie = 0;
 266         int gzip_ok = 0;
 267         wcsession *TheSession, *sptr;
 268         char httpauth_string[1024];
 269         char httpauth_user[1024];
 270         char httpauth_pass[1024];
 271         int session_is_new = 0;
 272         int nLine = 0;
 273         int LineLen;
 274         void *vLine;
 275         StrBuf *Buf, *Line, *LastLine, *HeaderName, *ReqLine, *ReqType, *HTTPVersion;
 276         StrBuf *accept_language = NULL;
 277         const char *pch, *pchs, *pche;
 278         HashList *HTTPHeaders;
 279
 280         strcpy(httpauth_string, "");
 281         strcpy(httpauth_user, DEFAULT_HTTPAUTH_USER);
 282         strcpy(httpauth_pass, DEFAULT_HTTPAUTH_PASS);
 283
 284         /*
 285          * Find out what it is that the web browser is asking for
 286          */
 287         HeaderName = NewStrBuf();
 288         Buf = NewStrBuf();
 289         LastLine = NULL;
 290         HTTPHeaders = NewHash(1, NULL);
 291
 292         /*
 293          * Read in the request
 294          */
 295         do {
 296                 nLine ++;
 297                 Line = NewStrBuf();
 298                 if (ReqGetStrBuf(sock, Line, Buf) < 0) return;
 299
 300                 LineLen = StrLength(Line);
 301
 302                 if (nLine == 1) {
 303                         ReqLine = Line;
 304                         continue;
 305                 }
 306                 if (LineLen == 0) {
 307                         FreeStrBuf(&Line);
 308                         continue;
 309                 }
 310
 311                 /* Do we need to Unfold? */
 312                 if ((LastLine != NULL) &&
 313                     (isspace(*ChrPtr(Line)))) {
 314                         pch = pchs = ChrPtr(Line);
 315                         pche = pchs + StrLength(Line);
 316                         while (isspace(*pch) && (pch < pche))
 317                                 pch ++;
 318                         StrBufCutLeft(Line, pch - pchs);
 319                         StrBufAppendBuf(LastLine, Line, 0);
 320                         FreeStrBuf(&Line);
 321                         continue;
 322                 }
 323
 324                 StrBufSanitizeAscii(Line, '§');
 325                 StrBufExtract_token(HeaderName, Line, 0, ':');
 326
 327                 pchs = ChrPtr(Line);
 328                 pch = pchs + StrLength(HeaderName) + 1;
 329                 pche = pchs + StrLength(Line);
 330                 while (isspace(*pch) && (pch < pche))
 331                         pch ++;
 332                 StrBufCutLeft(Line, pch - pchs);
 333
 334                 StrBufUpCase(HeaderName);
 335                 Put(HTTPHeaders, SKEY(HeaderName), Line, HFreeStrBuf);
 336                 LastLine = Line;
 337         } while (LineLen > 0);
 338         FreeStrBuf(&HeaderName);
 339
 340 /*///   dbg_PrintHash(HTTPHeaders, nix, NULL); */
 341
 342
 343         /*
 344          * Can we compress?
 345          */
 346         if (GetHash(HTTPHeaders, HKEY("ACCEPT-ENCODING"), &vLine) &&
 347             (vLine != NULL)) {
 348                 buf = ChrPtr((StrBuf*)vLine);
 349                 if (strstr(&buf[16], "gzip")) {
 350                         gzip_ok = 1;
 351                 }
 352         }
 353
 354         /*
 355          * Browser-based sessions use cookies for session authentication
 356          */
 357         if (GetHash(HTTPHeaders, HKEY("COOKIE"), &vLine) &&
 358             (vLine != NULL)) {
 359                 cookie_to_stuff(vLine, &desired_session,
 360                                 NULL, NULL, NULL);
 361                 got_cookie = 1;
 362         }
 363
 364         /*
 365          * GroupDAV-based sessions use HTTP authentication
 366          */
 367         if (GetHash(HTTPHeaders, HKEY("AUTHORIZATION"), &vLine) &&
 368             (vLine != NULL)) {
 369                 Line = (StrBuf*)vLine;
 370                 if (strncasecmp(ChrPtr(Line), "Basic", 5) == 0) {
 371                         StrBufCutLeft(Line, 6);
 372                         CtdlDecodeBase64(httpauth_string, ChrPtr(Line), StrLength(Line));
 373                         extract_token(httpauth_user, httpauth_string, 0, ':', sizeof httpauth_user);
 374                         extract_token(httpauth_pass, httpauth_string, 1, ':', sizeof httpauth_pass);
 375                 }
 376                 else
 377                         lprintf(1, "Authentication scheme not supported! [%s]\n", ChrPtr(Line));
 378         }
 379
 380         if (GetHash(HTTPHeaders, HKEY("IF-MODIFIED-SINCE"), &vLine) &&
 381             (vLine != NULL)) {
 382                 if_modified_since = httpdate_to_timestamp((StrBuf*)vLine);
 383         }
 384
 385         if (GetHash(HTTPHeaders, HKEY("ACCEPT-LANGUAGE"), &vLine) &&
 386             (vLine != NULL)) {
 387                 accept_language = (StrBuf*) vLine;
 388         }
 389
 390
 391         ReqType = NewStrBuf();
 392         HTTPVersion = NewStrBuf();
 393         StrBufExtract_token(HTTPVersion, ReqLine, 2, ' ');
 394         StrBufExtract_token(ReqType, ReqLine, 0, ' ');
 395         StrBufCutLeft(ReqLine, StrLength(ReqType) + 1);
 396         StrBufCutRight(ReqLine, StrLength(HTTPVersion) + 1);
 397
 398         /*
 399          * If the request is prefixed by "/webcit" then chop that off.  This
 400          * allows a front end web server to forward all /webcit requests to us
 401          * while still using the same web server port for other things.
 402          */
 403         if ( (StrLength(ReqLine) >= 8) && (strstr(ChrPtr(ReqLine), "/webcit/")) ) {
 404                 StrBufCutLeft(ReqLine, 7);
 405         }
 406
 407         /* Begin parsing the request. */
 408 #ifdef TECH_PREVIEW
 409         if ((strncmp(ChrPtr(ReqLine), "/sslg", 5) != 0) &&
 410             (strncmp(ChrPtr(ReqLine), "/static/", 8) != 0) &&
 411             (strncmp(ChrPtr(ReqLine), "/tiny_mce/", 10) != 0) &&
 412             (strncmp(ChrPtr(ReqLine), "/wholist_section", 16) != 0) &&
 413             (strstr(ChrPtr(ReqLine), "wholist_section") == NULL)) {
 414 #endif
 415                 lprintf(5, "HTTP: %s %s %s\n", ChrPtr(ReqType), ChrPtr(ReqLine), ChrPtr(HTTPVersion));
 416 #ifdef TECH_PREVIEW
 417         }
 418 #endif
 419
 420         /** Check for bogus requests */
 421         if ((StrLength(HTTPVersion) == 0) ||
 422             (StrLength(ReqType) == 0) ||
 423             is_bogus(ReqLine)) {
 424                 StrBufPlain(ReqLine, HKEY("/404 HTTP/1.1"));
 425                 StrBufPlain(ReqType, HKEY("GET"));
 426         }
 427         FreeStrBuf(&HTTPVersion);
 428
 429         /**
 430          * While we're at it, gracefully handle requests for the
 431          * robots.txt and favicon.ico files.
 432          */
 433         if (!strncasecmp(ChrPtr(ReqLine), "/robots.txt", 11)) {
 434                 StrBufPlain(ReqLine,
 435                             HKEY("/static/robots.txt"
 436                                  "?force_close_session=yes HTTP/1.1"));
 437                 StrBufPlain(ReqType, HKEY("GET"));
 438         }
 439         else if (!strncasecmp(ChrPtr(ReqLine), "/favicon.ico", 12)) {
 440                 StrBufPlain(ReqLine, HKEY("/static/favicon.ico"));
 441                 StrBufPlain(ReqType, HKEY("GET"));
 442         }
 443
 444         /**
 445          * These are the URL's which may be executed without a
 446          * session cookie already set.  If it's not one of these,
 447          * force the session to close because cookies are
 448          * probably disabled on the client browser.
 449          */
 450         else if ( (StrLength(ReqLine) > 1 )
 451                 && (strncasecmp(ChrPtr(ReqLine), "/listsub", 8))
 452                 && (strncasecmp(ChrPtr(ReqLine), "/freebusy", 9))
 453                 && (strncasecmp(ChrPtr(ReqLine), "/do_logout", 10))
 454                 && (strncasecmp(ChrPtr(ReqLine), "/groupdav", 9))
 455                 && (strncasecmp(ChrPtr(ReqLine), "/static", 7))
 456                 && (strncasecmp(ChrPtr(ReqLine), "/rss", 4))
 457                 && (strncasecmp(ChrPtr(ReqLine), "/404", 4))
 458                 && (got_cookie == 0)) {
 459                 StrBufPlain(ReqLine,
 460                             HKEY("/static/nocookies.html"
 461                                  "?force_close_session=yes"));
 462         }
 463
 464         /**
 465          * See if there's an existing session open with the desired ID or user/pass
 466          */
 467         TheSession = NULL;
 468
 469         if (TheSession == NULL) {
 470                 pthread_mutex_lock(&SessionListMutex);
 471                 for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
 472
 473                         /** If HTTP-AUTH, look for a session with matching credentials */
 474                         if ( (!IsEmptyStr(httpauth_user))
 475                              &&(!strcasecmp(ChrPtr(sptr->httpauth_user), httpauth_user))
 476                              &&(!strcasecmp(ChrPtr(sptr->httpauth_pass), httpauth_pass)) ) {
 477                                 TheSession = sptr;
 478                         }
 479
 480                         /** If cookie-session, look for a session with matching session ID */
 481                         if ( (desired_session != 0) && (sptr->wc_session == desired_session)) {
 482                                 TheSession = sptr;
 483                         }
 484
 485                 }
 486                 pthread_mutex_unlock(&SessionListMutex);
 487         }
 488
 489         /**
 490          * Create a new session if we have to
 491          */
 492         if (TheSession == NULL) {
 493                 lprintf(3, "Creating a new session\n");
 494                 TheSession = (wcsession *)
 495                         malloc(sizeof(wcsession));
 496                 memset(TheSession, 0, sizeof(wcsession));
 497                 TheSession->serv_sock = (-1);
 498                 TheSession->chat_sock = (-1);
 499
 500                 /* If we're recreating a session that expired, it's best to give it the same
 501                  * session number that it had before.  The client browser ought to pick up
 502                  * the new session number and start using it, but in some rare situations it
 503                  * doesn't, and that's a Bad Thing because it causes lots of spurious sessions
 504                  * to get created.
 505                  */
 506                 if (desired_session == 0) {
 507                         TheSession->wc_session = GenerateSessionID();
 508                 }
 509                 else {
 510                         TheSession->wc_session = desired_session;
 511                 }
 512
 513                 if (TheSession->httpauth_user != NULL){
 514                         FlushStrBuf(TheSession->httpauth_user);
 515                         StrBufAppendBufPlain(TheSession->httpauth_user, httpauth_user, -1, 0);
 516                 }
 517                 else TheSession->httpauth_user = NewStrBufPlain(httpauth_user, -1);
 518                 if (TheSession->httpauth_user != NULL){
 519                         FlushStrBuf(TheSession->httpauth_pass);
 520                         StrBufAppendBufPlain(TheSession->httpauth_pass, httpauth_user, -1, 0);
 521                 }
 522                 else TheSession->httpauth_pass = NewStrBufPlain(httpauth_user, -1);
 523
 524                 TheSession->CLineBuf = NewStrBuf();
 525                 TheSession->hash_prefs = NewHash(1,NULL);       /* Get a hash table for the user preferences */
 526                 pthread_mutex_init(&TheSession->SessionMutex, NULL);
 527                 pthread_mutex_lock(&SessionListMutex);
 528                 TheSession->nonce = rand();
 529                 TheSession->next = SessionList;
 530                 TheSession->is_mobile = -1;
 531                 SessionList = TheSession;
 532                 pthread_mutex_unlock(&SessionListMutex);
 533                 session_is_new = 1;
 534         }
 535
 536         /*
 537          * A future improvement might be to check the session integrity
 538          * at this point before continuing.
 539          */
 540
 541         /*
 542          * Bind to the session and perform the transaction
 543          */
 544         pthread_mutex_lock(&TheSession->SessionMutex);          /* bind */
 545         pthread_setspecific(MyConKey, (void *)TheSession);
 546
 547         TheSession->urlstrings = NewHash(1,NULL);
 548         TheSession->vars = NewHash(1,NULL);
 549         TheSession->http_sock = *sock;
 550         TheSession->lastreq = time(NULL);                       /* log */
 551         TheSession->gzip_ok = gzip_ok;
 552 #ifdef ENABLE_NLS
 553         if (session_is_new) {
 554                 httplang_to_locale(accept_language);
 555         }
 556         go_selected_language();                                 /* set locale */
 557 #endif
 558         session_loop(HTTPHeaders, ReqLine, ReqType, Buf);                               /* do transaction */
 559 #ifdef ENABLE_NLS
 560         stop_selected_language();                               /* unset locale */
 561 #endif
 562         DeleteHash(&TheSession->summ);
 563         DeleteHash(&TheSession->urlstrings);
 564         DeleteHash(&TheSession->vars);
 565         FreeStrBuf(&TheSession->WBuf);
 566         FreeStrBuf(&TheSession->HBuf);
 567
 568
 569         pthread_mutex_unlock(&TheSession->SessionMutex);        /* unbind */
 570
 571         /* Free the request buffer */
 572         DeleteHash(&HTTPHeaders);
 573         FreeStrBuf(&ReqLine);
 574         FreeStrBuf(&ReqType);
 575         FreeStrBuf(&Buf);
 576         /*
 577          * Free up any session-local substitution variables which
 578          * were set during this transaction
 579          */
 580
 581
 582 }
 583
 584 void tmplput_nonce(StrBuf *Target, WCTemplputParams *TP)
 585 {
 586         wcsession *WCC = WC;
 587         StrBufAppendPrintf(Target, "%ld",
 588                            (WCC != NULL)? WCC->nonce:0);
 589 }
 590
 591 void tmplput_current_user(StrBuf *Target, WCTemplputParams *TP)
 592 {
 593         StrBufAppendTemplate(Target, TP, WC->wc_fullname, 0);
 594 }
 595
 596 void tmplput_current_room(StrBuf *Target, WCTemplputParams *TP)
 597 {
 598         StrBufAppendTemplate(Target, TP, WC->wc_roomname, 0);
 599 }
 600
 601
 602
 603 void
 604 InitModule_CONTEXT
 605 (void)
 606 {
 607         RegisterNamespace("CURRENT_USER", 0, 1, tmplput_current_user, CTX_NONE);
 608         RegisterNamespace("CURRENT_ROOM", 0, 1, tmplput_current_room, CTX_NONE);
 609         RegisterNamespace("NONCE", 0, 0, tmplput_nonce, 0);
 610 }