Shared TDE VNC library sources
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libtdevnc/libvncserver/websockets.c

455 lines
13 KiB

/*
* websockets.c - deal with WebSockets clients.
*
* This code should be independent of any changes in the RFB protocol. It is
* an additional handshake and framing of normal sockets:
* http://www.whatwg.org/specs/web-socket-protocol/
*
*/
/*
* Copyright (C) 2010 Joel Martin
*
* 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
#endif
#include <rfb/rfb.h>
/* errno */
#include <errno.h>
#ifdef LIBVNCSERVER_HAVE_ENDIAN_H
#include <endian.h>
#elif LIBVNCSERVER_HAVE_SYS_ENDIAN_H
#include <sys/endian.h>
#endif
#ifdef LIBVNCSERVER_HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#include <string.h>
#if LIBVNCSERVER_UNISTD_H
#include <unistd.h>
#endif
#include "rfb/rfbconfig.h"
#include "rfbssl.h"
#include "rfbcrypto.h"
#include "ws_decode.h"
#if 0
#include <sys/syscall.h>
static int gettid() {
return (int)syscall(SYS_gettid);
}
#endif
#define FLASH_POLICY_RESPONSE "<cross-domain-policy><allow-access-from domain=\"*\" to-ports=\"*\" /></cross-domain-policy>\n"
#define SZ_FLASH_POLICY_RESPONSE 93
/*
* draft-ietf-hybi-thewebsocketprotocol-10
* 5.2.2. Sending the Server's Opening Handshake
*/
#define GUID "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
#define SERVER_HANDSHAKE_HYBI "HTTP/1.1 101 Switching Protocols\r\n\
Upgrade: websocket\r\n\
Connection: Upgrade\r\n\
Sec-WebSocket-Accept: %s\r\n\
Sec-WebSocket-Protocol: %s\r\n\
\r\n"
#define SERVER_HANDSHAKE_HYBI_NO_PROTOCOL "HTTP/1.1 101 Switching Protocols\r\n\
Upgrade: websocket\r\n\
Connection: Upgrade\r\n\
Sec-WebSocket-Accept: %s\r\n\
\r\n"
#define WEBSOCKETS_CLIENT_CONNECT_WAIT_MS 100
#define WEBSOCKETS_CLIENT_SEND_WAIT_MS 100
#define WEBSOCKETS_MAX_HANDSHAKE_LEN 4096
#if defined(__linux__) && defined(NEED_TIMEVAL)
struct timeval
{
long int tv_sec,tv_usec;
}
;
#endif
static rfbBool webSocketsHandshake(rfbClientPtr cl, char *scheme);
static int webSocketsEncodeHybi(rfbClientPtr cl, const char *src, int len, char **dst);
static int ws_read(void *cl, char *buf, size_t len);
static int
min (int a, int b) {
return a < b ? a : b;
}
static void webSocketsGenSha1Key(char *target, int size, char *key)
{
struct iovec iov[2];
unsigned char hash[20];
iov[0].iov_base = key;
iov[0].iov_len = strlen(key);
iov[1].iov_base = GUID;
iov[1].iov_len = sizeof(GUID) - 1;
digestsha1(iov, 2, hash);
if (-1 == b64_ntop(hash, sizeof(hash), target, size))
rfbErr("b64_ntop failed\n");
}
/*
* rfbWebSocketsHandshake is called to handle new WebSockets connections
*/
rfbBool
webSocketsCheck (rfbClientPtr cl)
{
char bbuf[4], *scheme;
int ret;
ret = rfbPeekExactTimeout(cl, bbuf, 4,
WEBSOCKETS_CLIENT_CONNECT_WAIT_MS);
if ((ret < 0) && (errno == ETIMEDOUT)) {
rfbLog("Normal socket connection\n");
return TRUE;
} else if (ret <= 0) {
rfbErr("webSocketsHandshake: unknown connection error\n");
return FALSE;
}
if (strncmp(bbuf, "<", 1) == 0) {
rfbLog("Got Flash policy request, sending response\n");
if (rfbWriteExact(cl, FLASH_POLICY_RESPONSE,
SZ_FLASH_POLICY_RESPONSE) < 0) {
rfbErr("webSocketsHandshake: failed sending Flash policy response");
}
return FALSE;
} else if (strncmp(bbuf, "\x16", 1) == 0 || strncmp(bbuf, "\x80", 1) == 0) {
rfbLog("Got TLS/SSL WebSockets connection\n");
if (-1 == rfbssl_init(cl)) {
rfbErr("webSocketsHandshake: rfbssl_init failed\n");
return FALSE;
}
ret = rfbPeekExactTimeout(cl, bbuf, 4, WEBSOCKETS_CLIENT_CONNECT_WAIT_MS);
scheme = "wss";
} else {
scheme = "ws";
}
if (strncmp(bbuf, "GET ", 4) != 0) {
rfbErr("webSocketsHandshake: invalid client header\n");
return FALSE;
}
rfbLog("Got '%s' WebSockets handshake\n", scheme);
if (!webSocketsHandshake(cl, scheme)) {
return FALSE;
}
/* Start WebSockets framing */
return TRUE;
}
static rfbBool
webSocketsHandshake(rfbClientPtr cl, char *scheme)
{
char *buf, *response, *line;
int n, linestart = 0, len = 0, llen, base64 = TRUE;
char prefix[5], trailer[17];
char *path = NULL, *host = NULL, *origin = NULL, *protocol = NULL;
char *key1 = NULL, *key2 = NULL, *key3 = NULL;
char *sec_ws_origin = NULL;
char *sec_ws_key = NULL;
char sec_ws_version = 0;
ws_ctx_t *wsctx = NULL;
buf = (char *) malloc(WEBSOCKETS_MAX_HANDSHAKE_LEN);
if (!buf) {
rfbLogPerror("webSocketsHandshake: malloc");
return FALSE;
}
response = (char *) malloc(WEBSOCKETS_MAX_HANDSHAKE_LEN);
if (!response) {
free(buf);
rfbLogPerror("webSocketsHandshake: malloc");
return FALSE;
}
while (len < WEBSOCKETS_MAX_HANDSHAKE_LEN-1) {
if ((n = rfbReadExactTimeout(cl, buf+len, 1,
WEBSOCKETS_CLIENT_SEND_WAIT_MS)) <= 0) {
if ((n < 0) && (errno == ETIMEDOUT)) {
break;
}
if (n == 0)
rfbLog("webSocketsHandshake: client gone\n");
else
rfbLogPerror("webSocketsHandshake: read");
free(response);
free(buf);
return FALSE;
}
len += 1;
llen = len - linestart;
if (((llen >= 2)) && (buf[len-1] == '\n')) {
line = buf+linestart;
if ((llen == 2) && (strncmp("\r\n", line, 2) == 0)) {
if (key1 && key2) {
if ((n = rfbReadExact(cl, buf+len, 8)) <= 0) {
if ((n < 0) && (errno == ETIMEDOUT)) {
break;
}
if (n == 0)
rfbLog("webSocketsHandshake: client gone\n");
else
rfbLogPerror("webSocketsHandshake: read");
free(response);
free(buf);
return FALSE;
}
rfbLog("Got key3\n");
key3 = buf+len;
len += 8;
} else {
buf[len] = '\0';
}
break;
} else if ((llen >= 16) && ((strncmp("GET ", line, min(llen,4))) == 0)) {
/* 16 = 4 ("GET ") + 1 ("/.*") + 11 (" HTTP/1.1\r\n") */
path = line+4;
buf[len-11] = '\0'; /* Trim trailing " HTTP/1.1\r\n" */
cl->wspath = strdup(path);
/* rfbLog("Got path: %s\n", path); */
} else if ((strncasecmp("host: ", line, min(llen,6))) == 0) {
host = line+6;
buf[len-2] = '\0';
/* rfbLog("Got host: %s\n", host); */
} else if ((strncasecmp("origin: ", line, min(llen,8))) == 0) {
origin = line+8;
buf[len-2] = '\0';
/* rfbLog("Got origin: %s\n", origin); */
} else if ((strncasecmp("sec-websocket-key1: ", line, min(llen,20))) == 0) {
key1 = line+20;
buf[len-2] = '\0';
/* rfbLog("Got key1: %s\n", key1); */
} else if ((strncasecmp("sec-websocket-key2: ", line, min(llen,20))) == 0) {
key2 = line+20;
buf[len-2] = '\0';
/* rfbLog("Got key2: %s\n", key2); */
/* HyBI */
} else if ((strncasecmp("sec-websocket-protocol: ", line, min(llen,24))) == 0) {
protocol = line+24;
buf[len-2] = '\0';
rfbLog("Got protocol: %s\n", protocol);
} else if ((strncasecmp("sec-websocket-origin: ", line, min(llen,22))) == 0) {
sec_ws_origin = line+22;
buf[len-2] = '\0';
} else if ((strncasecmp("sec-websocket-key: ", line, min(llen,19))) == 0) {
sec_ws_key = line+19;
buf[len-2] = '\0';
} else if ((strncasecmp("sec-websocket-version: ", line, min(llen,23))) == 0) {
sec_ws_version = strtol(line+23, NULL, 10);
buf[len-2] = '\0';
}
linestart = len;
}
}
/* older hixie handshake, this could be removed if
* a final standard is established -- removed now */
if (!sec_ws_version) {
rfbErr("Hixie no longer supported\n");
free(response);
free(buf);
return FALSE;
}
if (!(path && host && (origin || sec_ws_origin))) {
rfbErr("webSocketsHandshake: incomplete client handshake\n");
free(response);
free(buf);
return FALSE;
}
if ((protocol) && (strstr(protocol, "binary"))) {
rfbLog(" - webSocketsHandshake: using binary/raw encoding\n");
base64 = FALSE;
protocol = "binary";
} else {
rfbLog(" - webSocketsHandshake: using base64 encoding\n");
base64 = TRUE;
if ((protocol) && (strstr(protocol, "base64"))) {
protocol = "base64";
} else {
protocol = "";
}
}
/*
* Generate the WebSockets server response based on the the headers sent
* by the client.
*/
char accept[B64LEN(SHA1_HASH_SIZE) + 1];
rfbLog(" - WebSockets client version hybi-%02d\n", sec_ws_version);
webSocketsGenSha1Key(accept, sizeof(accept), sec_ws_key);
if(strlen(protocol) > 0) {
len = snprintf(response, WEBSOCKETS_MAX_HANDSHAKE_LEN,
SERVER_HANDSHAKE_HYBI, accept, protocol);
} else {
len = snprintf(response, WEBSOCKETS_MAX_HANDSHAKE_LEN,
SERVER_HANDSHAKE_HYBI_NO_PROTOCOL, accept);
}
if (rfbWriteExact(cl, response, len) < 0) {
rfbErr("webSocketsHandshake: failed sending WebSockets response\n");
free(response);
free(buf);
return FALSE;
}
/* rfbLog("webSocketsHandshake: %s\n", response); */
free(response);
free(buf);
wsctx = calloc(1, sizeof(ws_ctx_t));
wsctx->encode = webSocketsEncodeHybi;
wsctx->decode = webSocketsDecodeHybi;
wsctx->ctxInfo.readFunc = ws_read;
wsctx->base64 = base64;
hybiDecodeCleanupComplete(wsctx);
cl->wsctx = (wsCtx *)wsctx;
return TRUE;
}
static int
ws_read(void *ctxPtr, char *buf, size_t len)
{
int n;
rfbClientPtr cl = ctxPtr;
if (cl->sslctx) {
n = rfbssl_read(cl, buf, len);
} else {
n = read(cl->sock, buf, len);
}
return n;
}
static int
webSocketsEncodeHybi(rfbClientPtr cl, const char *src, int len, char **dst)
{
int blen, ret = -1, sz = 0;
unsigned char opcode = '\0'; /* TODO: option! */
ws_header_t *header;
ws_ctx_t *wsctx = (ws_ctx_t *)cl->wsctx;
/* Optional opcode:
* 0x0 - continuation
* 0x1 - text frame (base64 encode buf)
* 0x2 - binary frame (use raw buf)
* 0x8 - connection close
* 0x9 - ping
* 0xA - pong
**/
if (!len) {
/* nothing to encode */
return 0;
}
header = (ws_header_t *)wsctx->codeBufEncode;
if (wsctx->base64) {
opcode = WS_OPCODE_TEXT_FRAME;
/* calculate the resulting size */
blen = B64LEN(len);
} else {
opcode = WS_OPCODE_BINARY_FRAME;
blen = len;
}
header->b0 = 0x80 | (opcode & 0x0f);
if (blen <= 125) {
header->b1 = (uint8_t)blen;
sz = 2;
} else if (blen <= 65536) {
header->b1 = 0x7e;
header->u.s16.l16 = WS_HTON16((uint16_t)blen);
sz = 4;
} else {
header->b1 = 0x7f;
header->u.s64.l64 = WS_HTON64(blen);
sz = 10;
}
if (wsctx->base64) {
if (-1 == (ret = b64_ntop((unsigned char *)src, len, wsctx->codeBufEncode + sz, sizeof(wsctx->codeBufEncode) - sz))) {
rfbErr("%s: Base 64 encode failed\n", __func__);
} else {
if (ret != blen)
rfbErr("%s: Base 64 encode; something weird happened\n", __func__);
ret += sz;
}
} else {
memcpy(wsctx->codeBufEncode + sz, src, len);
ret = sz + len;
}
*dst = wsctx->codeBufEncode;
return ret;
}
int
webSocketsEncode(rfbClientPtr cl, const char *src, int len, char **dst)
{
return webSocketsEncodeHybi(cl, src, len, dst);
}
int
webSocketsDecode(rfbClientPtr cl, char *dst, int len)
{
ws_ctx_t *wsctx = (ws_ctx_t *)cl->wsctx;
wsctx->ctxInfo.ctxPtr = cl;
return webSocketsDecodeHybi(wsctx, dst, len);
}
/* returns TRUE if there is data waiting to be read in our internal buffer
* or if is there any pending data in the buffer of the SSL implementation
*/
rfbBool
webSocketsHasDataInBuffer(rfbClientPtr cl)
{
ws_ctx_t *wsctx = (ws_ctx_t *)cl->wsctx;
if (wsctx && wsctx->readlen)
return TRUE;
return (cl->sslctx && rfbssl_pending(cl) > 0);
}