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|
/*
* httpd.c - a simple HTTP server
*/
/*
* Copyright (C) 2011-2012 Christian Beier <dontmind@freeshell.org>
* Copyright (C) 2002 RealVNC Ltd.
* Copyright (C) 1999 AT&T Laboratories Cambridge. All Rights Reserved.
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this software; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
* USA.
*/
#ifdef __STRICT_ANSI__
#define _BSD_SOURCE
#define _POSIX_SOURCE
#endif
#include <rfb/rfb.h>
#include <ctype.h>
#ifdef LIBVNCSERVER_HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef LIBVNCSERVER_HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef LIBVNCSERVER_HAVE_FCNTL_H
#include <fcntl.h>
#endif
#include <errno.h>
#ifdef WIN32
#include <io.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#define close closesocket
#if defined(_MSC_VER)
#include <BaseTsd.h> /* For the missing ssize_t */
#define ssize_t SSIZE_T
#define read _read /* Prevent POSIX deprecation warnings */
#endif
#else
#ifdef LIBVNCSERVER_HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#ifdef LIBVNCSERVER_HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef LIBVNCSERVER_HAVE_NETINET_IN_H
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <netdb.h>
#include <arpa/inet.h>
#endif
#include <pwd.h>
#endif
#ifdef USE_LIBWRAP
#include <tcpd.h>
#endif
#define NOT_FOUND_STR "HTTP/1.0 404 Not found\r\nConnection: close\r\n\r\n" \
"<HEAD><TITLE>File Not Found</TITLE></HEAD>\n" \
"<BODY><H1>File Not Found</H1></BODY>\n"
#define INVALID_REQUEST_STR "HTTP/1.0 400 Invalid Request\r\nConnection: close\r\n\r\n" \
"<HEAD><TITLE>Invalid Request</TITLE></HEAD>\n" \
"<BODY><H1>Invalid request</H1></BODY>\n"
#define OK_STR "HTTP/1.0 200 OK\r\nConnection: close\r\n"
static void httpProcessInput(rfbScreenInfoPtr screen);
static rfbBool compareAndSkip(char **ptr, const char *str);
static rfbBool parseParams(const char *request, char *result, int max_bytes);
static rfbBool validateString(char *str);
#define BUF_SIZE 32768
static char buf[BUF_SIZE];
static size_t buf_filled=0;
/*
* httpInitSockets sets up the TCP socket to listen for HTTP connections.
*/
void
rfbHttpInitSockets(rfbScreenInfoPtr rfbScreen)
{
if (rfbScreen->httpInitDone)
return;
rfbScreen->httpInitDone = TRUE;
if (!rfbScreen->httpDir)
return;
if (rfbScreen->httpPort == 0) {
rfbScreen->httpPort = rfbScreen->port-100;
}
if ((rfbScreen->httpListenSock =
rfbListenOnTCPPort(rfbScreen->httpPort, rfbScreen->listenInterface)) < 0) {
rfbLogPerror("ListenOnTCPPort");
return;
}
rfbLog("Listening for HTTP connections on TCP port %d\n", rfbScreen->httpPort);
rfbLog(" URL http://%s:%d\n",rfbScreen->thisHost,rfbScreen->httpPort);
#ifdef LIBVNCSERVER_IPv6
if (rfbScreen->http6Port == 0) {
rfbScreen->http6Port = rfbScreen->ipv6port-100;
}
if ((rfbScreen->httpListen6Sock
= rfbListenOnTCP6Port(rfbScreen->http6Port, rfbScreen->listen6Interface)) < 0) {
/* ListenOnTCP6Port has its own detailed error printout */
return;
}
rfbLog("Listening for HTTP connections on TCP6 port %d\n", rfbScreen->http6Port);
rfbLog(" URL http://%s:%d\n",rfbScreen->thisHost,rfbScreen->http6Port);
#endif
}
void rfbHttpShutdownSockets(rfbScreenInfoPtr rfbScreen) {
if(rfbScreen->httpSock>-1) {
close(rfbScreen->httpSock);
FD_CLR(rfbScreen->httpSock,&rfbScreen->allFds);
rfbScreen->httpSock=-1;
}
if(rfbScreen->httpListenSock>-1) {
close(rfbScreen->httpListenSock);
FD_CLR(rfbScreen->httpListenSock,&rfbScreen->allFds);
rfbScreen->httpListenSock=-1;
}
if(rfbScreen->httpListen6Sock>-1) {
close(rfbScreen->httpListen6Sock);
FD_CLR(rfbScreen->httpListen6Sock,&rfbScreen->allFds);
rfbScreen->httpListen6Sock=-1;
}
}
/*
* httpCheckFds is called from ProcessInputEvents to check for input on the
* HTTP socket(s). If there is input to process, httpProcessInput is called.
*/
void
rfbHttpCheckFds(rfbScreenInfoPtr rfbScreen)
{
int nfds;
fd_set fds;
struct timeval tv;
#ifdef LIBVNCSERVER_IPv6
struct sockaddr_storage addr;
#else
struct sockaddr_in addr;
#endif
socklen_t addrlen = sizeof(addr);
if (!rfbScreen->httpDir)
return;
if (rfbScreen->httpListenSock < 0)
return;
FD_ZERO(&fds);
FD_SET(rfbScreen->httpListenSock, &fds);
if (rfbScreen->httpListen6Sock >= 0) {
FD_SET(rfbScreen->httpListen6Sock, &fds);
}
if (rfbScreen->httpSock >= 0) {
FD_SET(rfbScreen->httpSock, &fds);
}
tv.tv_sec = 0;
tv.tv_usec = 0;
nfds = select(rfbMax(rfbScreen->httpListen6Sock, rfbMax(rfbScreen->httpSock,rfbScreen->httpListenSock)) + 1, &fds, NULL, NULL, &tv);
if (nfds == 0) {
return;
}
if (nfds < 0) {
#ifdef WIN32
errno = WSAGetLastError();
#endif
if (errno != EINTR)
rfbLogPerror("httpCheckFds: select");
return;
}
if ((rfbScreen->httpSock >= 0) && FD_ISSET(rfbScreen->httpSock, &fds)) {
httpProcessInput(rfbScreen);
}
if (FD_ISSET(rfbScreen->httpListenSock, &fds) || FD_ISSET(rfbScreen->httpListen6Sock, &fds)) {
if (rfbScreen->httpSock >= 0) close(rfbScreen->httpSock);
if(FD_ISSET(rfbScreen->httpListenSock, &fds)) {
if ((rfbScreen->httpSock = accept(rfbScreen->httpListenSock, (struct sockaddr *)&addr, &addrlen)) < 0) {
rfbLogPerror("httpCheckFds: accept");
return;
}
}
else if(FD_ISSET(rfbScreen->httpListen6Sock, &fds)) {
if ((rfbScreen->httpSock = accept(rfbScreen->httpListen6Sock, (struct sockaddr *)&addr, &addrlen)) < 0) {
rfbLogPerror("httpCheckFds: accept");
return;
}
}
#ifdef USE_LIBWRAP
char host[1024];
#ifdef LIBVNCSERVER_IPv6
if(getnameinfo((struct sockaddr*)&addr, addrlen, host, sizeof(host), NULL, 0, NI_NUMERICHOST) != 0) {
rfbLogPerror("httpCheckFds: error in getnameinfo");
host[0] = '\0';
}
#else
memcpy(host, inet_ntoa(addr.sin_addr), sizeof(host));
#endif
if(!hosts_ctl("vnc",STRING_UNKNOWN, host,
STRING_UNKNOWN)) {
rfbLog("Rejected HTTP connection from client %s\n",
host);
close(rfbScreen->httpSock);
rfbScreen->httpSock=-1;
return;
}
#endif
if(!rfbSetNonBlocking(rfbScreen->httpSock)) {
close(rfbScreen->httpSock);
rfbScreen->httpSock=-1;
return;
}
/*AddEnabledDevice(httpSock);*/
}
}
static void
httpCloseSock(rfbScreenInfoPtr rfbScreen)
{
close(rfbScreen->httpSock);
rfbScreen->httpSock = -1;
buf_filled = 0;
}
static rfbClientRec cl;
/*
* httpProcessInput is called when input is received on the HTTP socket.
*/
static void
httpProcessInput(rfbScreenInfoPtr rfbScreen)
{
#ifdef LIBVNCSERVER_IPv6
struct sockaddr_storage addr;
#else
struct sockaddr_in addr;
#endif
socklen_t addrlen = sizeof(addr);
char fullFname[512];
char params[1024];
char *ptr;
char *fname;
unsigned int maxFnameLen;
FILE* fd;
rfbBool performSubstitutions = FALSE;
char str[256+32];
#ifndef WIN32
char* user=getenv("USER");
#endif
cl.sock=rfbScreen->httpSock;
if (strlen(rfbScreen->httpDir) > 255) {
rfbErr("-httpd directory too long\n");
httpCloseSock(rfbScreen);
return;
}
strcpy(fullFname, rfbScreen->httpDir);
fname = &fullFname[strlen(fullFname)];
maxFnameLen = 511 - strlen(fullFname);
buf_filled=0;
/* Read data from the HTTP client until we get a complete request. */
while (1) {
ssize_t got;
if (buf_filled > sizeof (buf)) {
rfbErr("httpProcessInput: HTTP request is too long\n");
httpCloseSock(rfbScreen);
return;
}
got = read (rfbScreen->httpSock, buf + buf_filled,
sizeof (buf) - buf_filled - 1);
if (got <= 0) {
if (got == 0) {
rfbErr("httpd: premature connection close\n");
} else {
#ifdef WIN32
errno=WSAGetLastError();
#endif
if (errno == EAGAIN) {
return;
}
rfbLogPerror("httpProcessInput: read");
}
httpCloseSock(rfbScreen);
return;
}
buf_filled += got;
buf[buf_filled] = '\0';
/* Is it complete yet (is there a blank line)? */
if (strstr (buf, "\r\r") || strstr (buf, "\n\n") ||
strstr (buf, "\r\n\r\n") || strstr (buf, "\n\r\n\r"))
break;
}
/* Process the request. */
if(rfbScreen->httpEnableProxyConnect) {
const static char* PROXY_OK_STR = "HTTP/1.0 200 OK\r\nContent-Type: octet-stream\r\nPragma: no-cache\r\n\r\n";
if(!strncmp(buf, "CONNECT ", 8)) {
if(atoi(strchr(buf, ':')+1)!=rfbScreen->port) {
rfbErr("httpd: CONNECT format invalid.\n");
rfbWriteExact(&cl,INVALID_REQUEST_STR, strlen(INVALID_REQUEST_STR));
httpCloseSock(rfbScreen);
return;
}
/* proxy connection */
rfbLog("httpd: client asked for CONNECT\n");
rfbWriteExact(&cl,PROXY_OK_STR,strlen(PROXY_OK_STR));
rfbNewClientConnection(rfbScreen,rfbScreen->httpSock);
rfbScreen->httpSock = -1;
return;
}
if (!strncmp(buf, "GET ",4) && !strncmp(strchr(buf,'/'),"/proxied.connection HTTP/1.", 27)) {
/* proxy connection */
rfbLog("httpd: client asked for /proxied.connection\n");
rfbWriteExact(&cl,PROXY_OK_STR,strlen(PROXY_OK_STR));
rfbNewClientConnection(rfbScreen,rfbScreen->httpSock);
rfbScreen->httpSock = -1;
return;
}
}
if (strncmp(buf, "GET ", 4)) {
rfbErr("httpd: no GET line\n");
httpCloseSock(rfbScreen);
return;
} else {
/* Only use the first line. */
buf[strcspn(buf, "\n\r")] = '\0';
}
if (strlen(buf) > maxFnameLen) {
rfbErr("httpd: GET line too long\n");
httpCloseSock(rfbScreen);
return;
}
if (sscanf(buf, "GET %s HTTP/1.", fname) != 1) {
rfbErr("httpd: couldn't parse GET line\n");
httpCloseSock(rfbScreen);
return;
}
if (fname[0] != '/') {
rfbErr("httpd: filename didn't begin with '/'\n");
rfbWriteExact(&cl, NOT_FOUND_STR, strlen(NOT_FOUND_STR));
httpCloseSock(rfbScreen);
return;
}
getpeername(rfbScreen->httpSock, (struct sockaddr *)&addr, &addrlen);
#ifdef LIBVNCSERVER_IPv6
{
char host[1024];
if(getnameinfo((struct sockaddr*)&addr, addrlen, host, sizeof(host), NULL, 0, NI_NUMERICHOST) != 0) {
rfbLogPerror("httpProcessInput: error in getnameinfo");
}
rfbLog("httpd: get '%s' for %s\n", fname+1, host);
}
#else
rfbLog("httpd: get '%s' for %s\n", fname+1,
inet_ntoa(addr.sin_addr));
#endif
/* Extract parameters from the URL string if necessary */
params[0] = '\0';
ptr = strchr(fname, '?');
if (ptr != NULL) {
*ptr = '\0';
if (!parseParams(&ptr[1], params, 1024)) {
params[0] = '\0';
rfbErr("httpd: bad parameters in the URL\n");
}
}
/* Basic protection against directory traversal outside webroot */
if (strstr(fname, "..")) {
rfbErr("httpd: URL should not contain '..'\n");
rfbWriteExact(&cl, NOT_FOUND_STR, strlen(NOT_FOUND_STR));
httpCloseSock(rfbScreen);
return;
}
/* If we were asked for '/', actually read the file index.vnc */
if (strcmp(fname, "/") == 0) {
strcpy(fname, "/index.vnc");
rfbLog("httpd: defaulting to '%s'\n", fname+1);
}
/* Substitutions are performed on files ending .vnc */
if (strlen(fname) >= 4 && strcmp(&fname[strlen(fname)-4], ".vnc") == 0) {
performSubstitutions = TRUE;
}
/* Open the file */
if ((fd = fopen(fullFname, "r")) == 0) {
rfbLogPerror("httpProcessInput: open");
rfbWriteExact(&cl, NOT_FOUND_STR, strlen(NOT_FOUND_STR));
httpCloseSock(rfbScreen);
return;
}
rfbWriteExact(&cl, OK_STR, strlen(OK_STR));
char *ext = strrchr(fname, '.');
char *contentType = "";
if(ext && strcasecmp(ext, ".vnc") == 0)
contentType = "Content-Type: text/html\r\n";
else if(ext && strcasecmp(ext, ".css") == 0)
contentType = "Content-Type: text/css\r\n";
else if(ext && strcasecmp(ext, ".svg") == 0)
contentType = "Content-Type: image/svg+xml\r\n";
rfbWriteExact(&cl, contentType, strlen(contentType));
/* end the header */
rfbWriteExact(&cl, "\r\n", 4);
while (1) {
int n = fread(buf, 1, BUF_SIZE-1, fd);
if (n < 0) {
rfbLogPerror("httpProcessInput: read");
fclose(fd);
httpCloseSock(rfbScreen);
return;
}
if (n == 0)
break;
if (performSubstitutions) {
/* Substitute $WIDTH, $HEIGHT, etc with the appropriate values.
This won't quite work properly if the .vnc file is longer than
BUF_SIZE, but it's reasonable to assume that .vnc files will
always be short. */
char *ptr = buf;
char *dollar;
buf[n] = 0; /* make sure it's null-terminated */
while ((dollar = strchr(ptr, '$'))!=NULL) {
rfbWriteExact(&cl, ptr, (dollar - ptr));
ptr = dollar;
if (compareAndSkip(&ptr, "$WIDTH")) {
sprintf(str, "%d", rfbScreen->width);
rfbWriteExact(&cl, str, strlen(str));
} else if (compareAndSkip(&ptr, "$HEIGHT")) {
sprintf(str, "%d", rfbScreen->height);
rfbWriteExact(&cl, str, strlen(str));
} else if (compareAndSkip(&ptr, "$APPLETWIDTH")) {
sprintf(str, "%d", rfbScreen->width);
rfbWriteExact(&cl, str, strlen(str));
} else if (compareAndSkip(&ptr, "$APPLETHEIGHT")) {
sprintf(str, "%d", rfbScreen->height + 32);
rfbWriteExact(&cl, str, strlen(str));
} else if (compareAndSkip(&ptr, "$PORT")) {
sprintf(str, "%d", rfbScreen->port);
rfbWriteExact(&cl, str, strlen(str));
} else if (compareAndSkip(&ptr, "$DESKTOP")) {
rfbWriteExact(&cl, rfbScreen->desktopName, strlen(rfbScreen->desktopName));
} else if (compareAndSkip(&ptr, "$DISPLAY")) {
sprintf(str, "%s:%d", rfbScreen->thisHost, rfbScreen->port-5900);
rfbWriteExact(&cl, str, strlen(str));
} else if (compareAndSkip(&ptr, "$USER")) {
#ifndef WIN32
if (user) {
rfbWriteExact(&cl, user,
strlen(user));
} else
#endif
rfbWriteExact(&cl, "?", 1);
} else if (compareAndSkip(&ptr, "$PARAMS")) {
if (params[0] != '\0')
rfbWriteExact(&cl, params, strlen(params));
} else {
if (!compareAndSkip(&ptr, "$$"))
ptr++;
if (rfbWriteExact(&cl, "$", 1) < 0) {
fclose(fd);
httpCloseSock(rfbScreen);
return;
}
}
}
if (rfbWriteExact(&cl, ptr, (&buf[n] - ptr)) < 0)
break;
} else {
/* For files not ending .vnc, just write out the buffer */
if (rfbWriteExact(&cl, buf, n) < 0)
break;
}
}
fclose(fd);
httpCloseSock(rfbScreen);
}
static rfbBool
compareAndSkip(char **ptr, const char *str)
{
if (strncmp(*ptr, str, strlen(str)) == 0) {
*ptr += strlen(str);
return TRUE;
}
return FALSE;
}
/*
* Parse the request tail after the '?' character, and format a sequence
* of <param> tags for inclusion into an HTML page with embedded applet.
*/
static rfbBool
parseParams(const char *request, char *result, int max_bytes)
{
char param_request[128];
char param_formatted[196];
const char *tail;
char *delim_ptr;
char *value_str;
int cur_bytes, len;
result[0] = '\0';
cur_bytes = 0;
tail = request;
for (;;) {
/* Copy individual "name=value" string into a buffer */
delim_ptr = strchr((char *)tail, '&');
if (delim_ptr == NULL) {
if (strlen(tail) >= sizeof(param_request)) {
return FALSE;
}
strcpy(param_request, tail);
} else {
len = delim_ptr - tail;
if (len >= sizeof(param_request)) {
return FALSE;
}
memcpy(param_request, tail, len);
param_request[len] = '\0';
}
/* Split the request into parameter name and value */
value_str = strchr(¶m_request[1], '=');
if (value_str == NULL) {
return FALSE;
}
*value_str++ = '\0';
if (strlen(value_str) == 0) {
return FALSE;
}
/* Validate both parameter name and value */
if (!validateString(param_request) || !validateString(value_str)) {
return FALSE;
}
/* Prepare HTML-formatted representation of the name=value pair */
len = sprintf(param_formatted,
"<PARAM NAME=\"%s\" VALUE=\"%s\">\n",
param_request, value_str);
if (cur_bytes + len + 1 > max_bytes) {
return FALSE;
}
strcat(result, param_formatted);
cur_bytes += len;
/* Go to the next parameter */
if (delim_ptr == NULL) {
break;
}
tail = delim_ptr + 1;
}
return TRUE;
}
/*
* Check if the string consists only of alphanumeric characters, '+'
* signs, underscores, dots, colons and square brackets.
* Replace all '+' signs with spaces.
*/
static rfbBool
validateString(char *str)
{
char *ptr;
for (ptr = str; *ptr != '\0'; ptr++) {
if (!isalnum(*ptr) && *ptr != '_' && *ptr != '.'
&& *ptr != ':' && *ptr != '[' && *ptr != ']' ) {
if (*ptr == '+') {
*ptr = ' ';
} else {
return FALSE;
}
}
}
return TRUE;
}
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