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