1 /*
2 * httpd.c - a simple HTTP server
3 */
4
5 /*
6 * Copyright (C) 2011-2012 Christian Beier <dontmind@freeshell.org>
7 * Copyright (C) 2002 RealVNC Ltd.
8 * Copyright (C) 1999 AT&T Laboratories Cambridge. All Rights Reserved.
9 *
10 * This is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This software is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this software; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
23 * USA.
24 */
25
26 #ifdef __STRICT_ANSI__
27 #define _BSD_SOURCE
28 #define _POSIX_SOURCE
29 #endif
30
31 #include <rfb/rfb.h>
32
33 #include <ctype.h>
34 #ifdef LIBVNCSERVER_HAVE_UNISTD_H
35 #include <unistd.h>
36 #endif
37 #ifdef LIBVNCSERVER_HAVE_SYS_TYPES_H
38 #include <sys/types.h>
39 #endif
40 #ifdef LIBVNCSERVER_HAVE_FCNTL_H
41 #include <fcntl.h>
42 #endif
43 #include <errno.h>
44
45 #ifdef WIN32
46 #include <io.h>
47 #include <winsock2.h>
48 #include <ws2tcpip.h>
49 #define close closesocket
50 #if defined(_MSC_VER)
51 #include <BaseTsd.h> /* For the missing ssize_t */
52 #define ssize_t SSIZE_T
53 #define read _read /* Prevent POSIX deprecation warnings */
54 #endif
55 #else
56 #ifdef LIBVNCSERVER_HAVE_SYS_TIME_H
57 #include <sys/time.h>
58 #endif
59 #ifdef LIBVNCSERVER_HAVE_SYS_SOCKET_H
60 #include <sys/socket.h>
61 #endif
62 #ifdef LIBVNCSERVER_HAVE_NETINET_IN_H
63 #include <netinet/in.h>
64 #include <netinet/tcp.h>
65 #include <netdb.h>
66 #include <arpa/inet.h>
67 #endif
68 #include <pwd.h>
69 #endif
70
71 #ifdef USE_LIBWRAP
72 #include <tcpd.h>
73 #endif
74
75
76 #define NOT_FOUND_STR "HTTP/1.0 404 Not found\r\nConnection: close\r\n\r\n" \
77 "<HEAD><TITLE>File Not Found</TITLE></HEAD>\n" \
78 "<BODY><H1>File Not Found</H1></BODY>\n"
79
80 #define INVALID_REQUEST_STR "HTTP/1.0 400 Invalid Request\r\nConnection: close\r\n\r\n" \
81 "<HEAD><TITLE>Invalid Request</TITLE></HEAD>\n" \
82 "<BODY><H1>Invalid request</H1></BODY>\n"
83
84 #define OK_STR "HTTP/1.0 200 OK\r\nConnection: close\r\n\r\n"
85 #define OK_STR_HTML "HTTP/1.0 200 OK\r\nConnection: close\r\nContent-Type: text/html\r\n\r\n"
86
87
88
89 static void httpProcessInput(rfbScreenInfoPtr screen);
90 static rfbBool compareAndSkip(char **ptr, const char *str);
91 static rfbBool parseParams(const char *request, char *result, int max_bytes);
92 static rfbBool validateString(char *str);
93
94 #define BUF_SIZE 32768
95
96 static char buf[BUF_SIZE];
97 static size_t buf_filled=0;
98
99 /*
100 * httpInitSockets sets up the TCP socket to listen for HTTP connections.
101 */
102
103 void
rfbHttpInitSockets(rfbScreenInfoPtr rfbScreen)104 rfbHttpInitSockets(rfbScreenInfoPtr rfbScreen)
105 {
106 if (rfbScreen->httpInitDone)
107 return;
108
109 rfbScreen->httpInitDone = TRUE;
110
111 if (!rfbScreen->httpDir)
112 return;
113
114 if (rfbScreen->httpPort == 0) {
115 rfbScreen->httpPort = rfbScreen->port-100;
116 }
117
118 if ((rfbScreen->httpListenSock =
119 rfbListenOnTCPPort(rfbScreen->httpPort, rfbScreen->listenInterface)) < 0) {
120 rfbLogPerror("ListenOnTCPPort");
121 return;
122 }
123 rfbLog("Listening for HTTP connections on TCP port %d\n", rfbScreen->httpPort);
124 rfbLog(" URL http://%s:%d\n",rfbScreen->thisHost,rfbScreen->httpPort);
125
126 #ifdef LIBVNCSERVER_IPv6
127 if (rfbScreen->http6Port == 0) {
128 rfbScreen->http6Port = rfbScreen->ipv6port-100;
129 }
130
131 if ((rfbScreen->httpListen6Sock
132 = rfbListenOnTCP6Port(rfbScreen->http6Port, rfbScreen->listen6Interface)) < 0) {
133 /* ListenOnTCP6Port has its own detailed error printout */
134 return;
135 }
136 rfbLog("Listening for HTTP connections on TCP6 port %d\n", rfbScreen->http6Port);
137 rfbLog(" URL http://%s:%d\n",rfbScreen->thisHost,rfbScreen->http6Port);
138 #endif
139 }
140
rfbHttpShutdownSockets(rfbScreenInfoPtr rfbScreen)141 void rfbHttpShutdownSockets(rfbScreenInfoPtr rfbScreen) {
142 if(rfbScreen->httpSock>-1) {
143 close(rfbScreen->httpSock);
144 FD_CLR(rfbScreen->httpSock,&rfbScreen->allFds);
145 rfbScreen->httpSock=-1;
146 }
147
148 if(rfbScreen->httpListenSock>-1) {
149 close(rfbScreen->httpListenSock);
150 FD_CLR(rfbScreen->httpListenSock,&rfbScreen->allFds);
151 rfbScreen->httpListenSock=-1;
152 }
153
154 if(rfbScreen->httpListen6Sock>-1) {
155 close(rfbScreen->httpListen6Sock);
156 FD_CLR(rfbScreen->httpListen6Sock,&rfbScreen->allFds);
157 rfbScreen->httpListen6Sock=-1;
158 }
159 }
160
161 /*
162 * httpCheckFds is called from ProcessInputEvents to check for input on the
163 * HTTP socket(s). If there is input to process, httpProcessInput is called.
164 */
165
166 void
rfbHttpCheckFds(rfbScreenInfoPtr rfbScreen)167 rfbHttpCheckFds(rfbScreenInfoPtr rfbScreen)
168 {
169 int nfds;
170 fd_set fds;
171 struct timeval tv;
172 #ifdef LIBVNCSERVER_IPv6
173 struct sockaddr_storage addr;
174 #else
175 struct sockaddr_in addr;
176 #endif
177 socklen_t addrlen = sizeof(addr);
178
179 if (!rfbScreen->httpDir)
180 return;
181
182 if (rfbScreen->httpListenSock < 0)
183 return;
184
185 FD_ZERO(&fds);
186 FD_SET(rfbScreen->httpListenSock, &fds);
187 if (rfbScreen->httpListen6Sock >= 0) {
188 FD_SET(rfbScreen->httpListen6Sock, &fds);
189 }
190 if (rfbScreen->httpSock >= 0) {
191 FD_SET(rfbScreen->httpSock, &fds);
192 }
193 tv.tv_sec = 0;
194 tv.tv_usec = 0;
195 nfds = select(max(rfbScreen->httpListen6Sock, max(rfbScreen->httpSock,rfbScreen->httpListenSock)) + 1, &fds, NULL, NULL, &tv);
196 if (nfds == 0) {
197 return;
198 }
199 if (nfds < 0) {
200 #ifdef WIN32
201 errno = WSAGetLastError();
202 #endif
203 if (errno != EINTR)
204 rfbLogPerror("httpCheckFds: select");
205 return;
206 }
207
208 if ((rfbScreen->httpSock >= 0) && FD_ISSET(rfbScreen->httpSock, &fds)) {
209 httpProcessInput(rfbScreen);
210 }
211
212 if (FD_ISSET(rfbScreen->httpListenSock, &fds) || FD_ISSET(rfbScreen->httpListen6Sock, &fds)) {
213 if (rfbScreen->httpSock >= 0) close(rfbScreen->httpSock);
214
215 if(FD_ISSET(rfbScreen->httpListenSock, &fds)) {
216 if ((rfbScreen->httpSock = accept(rfbScreen->httpListenSock, (struct sockaddr *)&addr, &addrlen)) < 0) {
217 rfbLogPerror("httpCheckFds: accept");
218 return;
219 }
220 }
221 else if(FD_ISSET(rfbScreen->httpListen6Sock, &fds)) {
222 if ((rfbScreen->httpSock = accept(rfbScreen->httpListen6Sock, (struct sockaddr *)&addr, &addrlen)) < 0) {
223 rfbLogPerror("httpCheckFds: accept");
224 return;
225 }
226 }
227
228 #ifdef USE_LIBWRAP
229 char host[1024];
230 #ifdef LIBVNCSERVER_IPv6
231 if(getnameinfo((struct sockaddr*)&addr, addrlen, host, sizeof(host), NULL, 0, NI_NUMERICHOST) != 0) {
232 rfbLogPerror("httpCheckFds: error in getnameinfo");
233 host[0] = '\0';
234 }
235 #else
236 memcpy(host, inet_ntoa(addr.sin_addr), sizeof(host));
237 #endif
238 if(!hosts_ctl("vnc",STRING_UNKNOWN, host,
239 STRING_UNKNOWN)) {
240 rfbLog("Rejected HTTP connection from client %s\n",
241 host);
242 close(rfbScreen->httpSock);
243 rfbScreen->httpSock=-1;
244 return;
245 }
246 #endif
247 if(!rfbSetNonBlocking(rfbScreen->httpSock)) {
248 close(rfbScreen->httpSock);
249 rfbScreen->httpSock=-1;
250 return;
251 }
252 /*AddEnabledDevice(httpSock);*/
253 }
254 }
255
256
257 static void
httpCloseSock(rfbScreenInfoPtr rfbScreen)258 httpCloseSock(rfbScreenInfoPtr rfbScreen)
259 {
260 close(rfbScreen->httpSock);
261 rfbScreen->httpSock = -1;
262 buf_filled = 0;
263 }
264
265 static rfbClientRec cl;
266
267 /*
268 * httpProcessInput is called when input is received on the HTTP socket.
269 */
270
271 static void
httpProcessInput(rfbScreenInfoPtr rfbScreen)272 httpProcessInput(rfbScreenInfoPtr rfbScreen)
273 {
274 #ifdef LIBVNCSERVER_IPv6
275 struct sockaddr_storage addr;
276 #else
277 struct sockaddr_in addr;
278 #endif
279 socklen_t addrlen = sizeof(addr);
280 char fullFname[512];
281 char params[1024];
282 char *ptr;
283 char *fname;
284 unsigned int maxFnameLen;
285 FILE* fd;
286 rfbBool performSubstitutions = FALSE;
287 char str[256+32];
288 #ifndef WIN32
289 char* user=getenv("USER");
290 #endif
291
292 cl.sock=rfbScreen->httpSock;
293
294 if (strlen(rfbScreen->httpDir) > 255) {
295 rfbErr("-httpd directory too long\n");
296 httpCloseSock(rfbScreen);
297 return;
298 }
299 strcpy(fullFname, rfbScreen->httpDir);
300 fname = &fullFname[strlen(fullFname)];
301 maxFnameLen = 511 - strlen(fullFname);
302
303 buf_filled=0;
304
305 /* Read data from the HTTP client until we get a complete request. */
306 while (1) {
307 ssize_t got;
308
309 if (buf_filled > sizeof (buf)) {
310 rfbErr("httpProcessInput: HTTP request is too long\n");
311 httpCloseSock(rfbScreen);
312 return;
313 }
314
315 got = read (rfbScreen->httpSock, buf + buf_filled,
316 sizeof (buf) - buf_filled - 1);
317
318 if (got <= 0) {
319 if (got == 0) {
320 rfbErr("httpd: premature connection close\n");
321 } else {
322 #ifdef WIN32
323 errno=WSAGetLastError();
324 #endif
325 if (errno == EAGAIN) {
326 return;
327 }
328 rfbLogPerror("httpProcessInput: read");
329 }
330 httpCloseSock(rfbScreen);
331 return;
332 }
333
334 buf_filled += got;
335 buf[buf_filled] = '\0';
336
337 /* Is it complete yet (is there a blank line)? */
338 if (strstr (buf, "\r\r") || strstr (buf, "\n\n") ||
339 strstr (buf, "\r\n\r\n") || strstr (buf, "\n\r\n\r"))
340 break;
341 }
342
343
344 /* Process the request. */
345 if(rfbScreen->httpEnableProxyConnect) {
346 const static char* PROXY_OK_STR = "HTTP/1.0 200 OK\r\nContent-Type: octet-stream\r\nPragma: no-cache\r\n\r\n";
347 if(!strncmp(buf, "CONNECT ", 8)) {
348 if(atoi(strchr(buf, ':')+1)!=rfbScreen->port) {
349 rfbErr("httpd: CONNECT format invalid.\n");
350 rfbWriteExact(&cl,INVALID_REQUEST_STR, strlen(INVALID_REQUEST_STR));
351 httpCloseSock(rfbScreen);
352 return;
353 }
354 /* proxy connection */
355 rfbLog("httpd: client asked for CONNECT\n");
356 rfbWriteExact(&cl,PROXY_OK_STR,strlen(PROXY_OK_STR));
357 rfbNewClientConnection(rfbScreen,rfbScreen->httpSock);
358 rfbScreen->httpSock = -1;
359 return;
360 }
361 if (!strncmp(buf, "GET ",4) && !strncmp(strchr(buf,'/'),"/proxied.connection HTTP/1.", 27)) {
362 /* proxy connection */
363 rfbLog("httpd: client asked for /proxied.connection\n");
364 rfbWriteExact(&cl,PROXY_OK_STR,strlen(PROXY_OK_STR));
365 rfbNewClientConnection(rfbScreen,rfbScreen->httpSock);
366 rfbScreen->httpSock = -1;
367 return;
368 }
369 }
370
371 if (strncmp(buf, "GET ", 4)) {
372 rfbErr("httpd: no GET line\n");
373 httpCloseSock(rfbScreen);
374 return;
375 } else {
376 /* Only use the first line. */
377 buf[strcspn(buf, "\n\r")] = '\0';
378 }
379
380 if (strlen(buf) > maxFnameLen) {
381 rfbErr("httpd: GET line too long\n");
382 httpCloseSock(rfbScreen);
383 return;
384 }
385
386 if (sscanf(buf, "GET %s HTTP/1.", fname) != 1) {
387 rfbErr("httpd: couldn't parse GET line\n");
388 httpCloseSock(rfbScreen);
389 return;
390 }
391
392 if (fname[0] != '/') {
393 rfbErr("httpd: filename didn't begin with '/'\n");
394 rfbWriteExact(&cl, NOT_FOUND_STR, strlen(NOT_FOUND_STR));
395 httpCloseSock(rfbScreen);
396 return;
397 }
398
399
400 getpeername(rfbScreen->httpSock, (struct sockaddr *)&addr, &addrlen);
401 #ifdef LIBVNCSERVER_IPv6
402 {
403 char host[1024];
404 if(getnameinfo((struct sockaddr*)&addr, addrlen, host, sizeof(host), NULL, 0, NI_NUMERICHOST) != 0) {
405 rfbLogPerror("httpProcessInput: error in getnameinfo");
406 }
407 rfbLog("httpd: get '%s' for %s\n", fname+1, host);
408 }
409 #else
410 rfbLog("httpd: get '%s' for %s\n", fname+1,
411 inet_ntoa(addr.sin_addr));
412 #endif
413
414 /* Extract parameters from the URL string if necessary */
415
416 params[0] = '\0';
417 ptr = strchr(fname, '?');
418 if (ptr != NULL) {
419 *ptr = '\0';
420 if (!parseParams(&ptr[1], params, 1024)) {
421 params[0] = '\0';
422 rfbErr("httpd: bad parameters in the URL\n");
423 }
424 }
425
426
427 /* If we were asked for '/', actually read the file index.vnc */
428
429 if (strcmp(fname, "/") == 0) {
430 strcpy(fname, "/index.vnc");
431 rfbLog("httpd: defaulting to '%s'\n", fname+1);
432 }
433
434 /* Substitutions are performed on files ending .vnc */
435
436 if (strlen(fname) >= 4 && strcmp(&fname[strlen(fname)-4], ".vnc") == 0) {
437 performSubstitutions = TRUE;
438 }
439
440 /* Open the file */
441
442 if ((fd = fopen(fullFname, "r")) == 0) {
443 rfbLogPerror("httpProcessInput: open");
444 rfbWriteExact(&cl, NOT_FOUND_STR, strlen(NOT_FOUND_STR));
445 httpCloseSock(rfbScreen);
446 return;
447 }
448
449 if(performSubstitutions) /* is the 'index.vnc' file */
450 rfbWriteExact(&cl, OK_STR_HTML, strlen(OK_STR_HTML));
451 else
452 rfbWriteExact(&cl, OK_STR, strlen(OK_STR));
453
454 while (1) {
455 int n = fread(buf, 1, BUF_SIZE-1, fd);
456 if (n < 0) {
457 rfbLogPerror("httpProcessInput: read");
458 fclose(fd);
459 httpCloseSock(rfbScreen);
460 return;
461 }
462
463 if (n == 0)
464 break;
465
466 if (performSubstitutions) {
467
468 /* Substitute $WIDTH, $HEIGHT, etc with the appropriate values.
469 This won't quite work properly if the .vnc file is longer than
470 BUF_SIZE, but it's reasonable to assume that .vnc files will
471 always be short. */
472
473 char *ptr = buf;
474 char *dollar;
475 buf[n] = 0; /* make sure it's null-terminated */
476
477 while ((dollar = strchr(ptr, '$'))!=NULL) {
478 rfbWriteExact(&cl, ptr, (dollar - ptr));
479
480 ptr = dollar;
481
482 if (compareAndSkip(&ptr, "$WIDTH")) {
483
484 sprintf(str, "%d", rfbScreen->width);
485 rfbWriteExact(&cl, str, strlen(str));
486
487 } else if (compareAndSkip(&ptr, "$HEIGHT")) {
488
489 sprintf(str, "%d", rfbScreen->height);
490 rfbWriteExact(&cl, str, strlen(str));
491
492 } else if (compareAndSkip(&ptr, "$APPLETWIDTH")) {
493
494 sprintf(str, "%d", rfbScreen->width);
495 rfbWriteExact(&cl, str, strlen(str));
496
497 } else if (compareAndSkip(&ptr, "$APPLETHEIGHT")) {
498
499 sprintf(str, "%d", rfbScreen->height + 32);
500 rfbWriteExact(&cl, str, strlen(str));
501
502 } else if (compareAndSkip(&ptr, "$PORT")) {
503
504 sprintf(str, "%d", rfbScreen->port);
505 rfbWriteExact(&cl, str, strlen(str));
506
507 } else if (compareAndSkip(&ptr, "$DESKTOP")) {
508
509 rfbWriteExact(&cl, rfbScreen->desktopName, strlen(rfbScreen->desktopName));
510
511 } else if (compareAndSkip(&ptr, "$DISPLAY")) {
512
513 sprintf(str, "%s:%d", rfbScreen->thisHost, rfbScreen->port-5900);
514 rfbWriteExact(&cl, str, strlen(str));
515
516 } else if (compareAndSkip(&ptr, "$USER")) {
517 #ifndef WIN32
518 if (user) {
519 rfbWriteExact(&cl, user,
520 strlen(user));
521 } else
522 #endif
523 rfbWriteExact(&cl, "?", 1);
524 } else if (compareAndSkip(&ptr, "$PARAMS")) {
525 if (params[0] != '\0')
526 rfbWriteExact(&cl, params, strlen(params));
527 } else {
528 if (!compareAndSkip(&ptr, "$$"))
529 ptr++;
530
531 if (rfbWriteExact(&cl, "$", 1) < 0) {
532 fclose(fd);
533 httpCloseSock(rfbScreen);
534 return;
535 }
536 }
537 }
538 if (rfbWriteExact(&cl, ptr, (&buf[n] - ptr)) < 0)
539 break;
540
541 } else {
542
543 /* For files not ending .vnc, just write out the buffer */
544
545 if (rfbWriteExact(&cl, buf, n) < 0)
546 break;
547 }
548 }
549
550 fclose(fd);
551 httpCloseSock(rfbScreen);
552 }
553
554
555 static rfbBool
compareAndSkip(char ** ptr,const char * str)556 compareAndSkip(char **ptr, const char *str)
557 {
558 if (strncmp(*ptr, str, strlen(str)) == 0) {
559 *ptr += strlen(str);
560 return TRUE;
561 }
562
563 return FALSE;
564 }
565
566 /*
567 * Parse the request tail after the '?' character, and format a sequence
568 * of <param> tags for inclusion into an HTML page with embedded applet.
569 */
570
571 static rfbBool
parseParams(const char * request,char * result,int max_bytes)572 parseParams(const char *request, char *result, int max_bytes)
573 {
574 char param_request[128];
575 char param_formatted[196];
576 const char *tail;
577 char *delim_ptr;
578 char *value_str;
579 int cur_bytes, len;
580
581 result[0] = '\0';
582 cur_bytes = 0;
583
584 tail = request;
585 for (;;) {
586 /* Copy individual "name=value" string into a buffer */
587 delim_ptr = strchr((char *)tail, '&');
588 if (delim_ptr == NULL) {
589 if (strlen(tail) >= sizeof(param_request)) {
590 return FALSE;
591 }
592 strcpy(param_request, tail);
593 } else {
594 len = delim_ptr - tail;
595 if (len >= sizeof(param_request)) {
596 return FALSE;
597 }
598 memcpy(param_request, tail, len);
599 param_request[len] = '\0';
600 }
601
602 /* Split the request into parameter name and value */
603 value_str = strchr(¶m_request[1], '=');
604 if (value_str == NULL) {
605 return FALSE;
606 }
607 *value_str++ = '\0';
608 if (strlen(value_str) == 0) {
609 return FALSE;
610 }
611
612 /* Validate both parameter name and value */
613 if (!validateString(param_request) || !validateString(value_str)) {
614 return FALSE;
615 }
616
617 /* Prepare HTML-formatted representation of the name=value pair */
618 len = sprintf(param_formatted,
619 "<PARAM NAME=\"%s\" VALUE=\"%s\">\n",
620 param_request, value_str);
621 if (cur_bytes + len + 1 > max_bytes) {
622 return FALSE;
623 }
624 strcat(result, param_formatted);
625 cur_bytes += len;
626
627 /* Go to the next parameter */
628 if (delim_ptr == NULL) {
629 break;
630 }
631 tail = delim_ptr + 1;
632 }
633 return TRUE;
634 }
635
636 /*
637 * Check if the string consists only of alphanumeric characters, '+'
638 * signs, underscores, dots, colons and square brackets.
639 * Replace all '+' signs with spaces.
640 */
641
642 static rfbBool
validateString(char * str)643 validateString(char *str)
644 {
645 char *ptr;
646
647 for (ptr = str; *ptr != '\0'; ptr++) {
648 if (!isalnum(*ptr) && *ptr != '_' && *ptr != '.'
649 && *ptr != ':' && *ptr != '[' && *ptr != ']' ) {
650 if (*ptr == '+') {
651 *ptr = ' ';
652 } else {
653 return FALSE;
654 }
655 }
656 }
657 return TRUE;
658 }
659
660