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libtdevnc/libvncserver/websockets.c

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/*
* 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>
#ifndef _MSC_VER
#include <resolv.h> /* __b64_ntop */
#endif
#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"
#if defined(__APPLE__)
#include <libkern/OSByteOrder.h>
#define WS_NTOH64(n) OSSwapBigToHostInt64(n)
#define WS_NTOH32(n) OSSwapBigToHostInt32(n)
#define WS_NTOH16(n) OSSwapBigToHostInt16(n)
#define WS_HTON64(n) OSSwapHostToBigInt64(n)
#define WS_HTON16(n) OSSwapHostToBigInt16(n)
#else
#define WS_NTOH64(n) htobe64(n)
#define WS_NTOH32(n) htobe32(n)
#define WS_NTOH16(n) htobe16(n)
#define WS_HTON64(n) htobe64(n)
#define WS_HTON16(n) htobe16(n)
#endif
#define B64LEN(__x) (((__x + 2) / 3) * 12 / 3)
#define WSHLENMAX 14 /* 2 + sizeof(uint64_t) + sizeof(uint32_t) */
#define WS_HYBI_MASK_LEN 4
#define ARRAYSIZE(a) ((sizeof(a) / sizeof((a[0]))) / (size_t)(!(sizeof(a) % sizeof((a[0])))))
enum {
WEBSOCKETS_VERSION_HIXIE,
WEBSOCKETS_VERSION_HYBI
};
#if 0
#include <sys/syscall.h>
static int gettid() {
return (int)syscall(SYS_gettid);
}
#endif
typedef int (*wsEncodeFunc)(rfbClientPtr cl, const char *src, int len, char **dst);
typedef int (*wsDecodeFunc)(rfbClientPtr cl, char *dst, int len);
enum {
/* header not yet received completely */
WS_HYBI_STATE_HEADER_PENDING,
/* data available */
WS_HYBI_STATE_DATA_AVAILABLE,
WS_HYBI_STATE_DATA_NEEDED,
/* received a complete frame */
WS_HYBI_STATE_FRAME_COMPLETE,
/* received part of a 'close' frame */
WS_HYBI_STATE_CLOSE_REASON_PENDING,
/* */
WS_HYBI_STATE_ERR
};
typedef union ws_mask_s {
char c[4];
uint32_t u;
} ws_mask_t;
/* XXX: The union and the structs do not need to be named.
* We are working around a bug present in GCC < 4.6 which prevented
* it from recognizing anonymous structs and unions.
* See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=4784
*/
typedef struct
#if __GNUC__
__attribute__ ((__packed__))
#endif
ws_header_s {
unsigned char b0;
unsigned char b1;
union {
struct
#if __GNUC__
__attribute__ ((__packed__))
#endif
{
uint16_t l16;
ws_mask_t m16;
} s16;
struct
#if __GNUC__
__attribute__ ((__packed__))
#endif
{
uint64_t l64;
ws_mask_t m64;
} s64;
ws_mask_t m;
} u;
} ws_header_t;
typedef struct ws_header_data_s {
ws_header_t *data;
/** bytes read */
int nRead;
/** mask value */
ws_mask_t mask;
/** length of frame header including payload len, but without mask */
int headerLen;
/** length of the payload data */
int payloadLen;
/** opcode */
unsigned char opcode;
} ws_header_data_t;
typedef struct ws_ctx_s {
char codeBufDecode[B64LEN(UPDATE_BUF_SIZE) + WSHLENMAX]; /* base64 + maximum frame header length */
char codeBufEncode[B64LEN(UPDATE_BUF_SIZE) + WSHLENMAX]; /* base64 + maximum frame header length */
char *writePos;
unsigned char *readPos;
int readlen;
int hybiDecodeState;
char carryBuf[3]; /* For base64 carry-over */
int carrylen;
int version;
int base64;
ws_header_data_t header;
int nReadRaw;
int nToRead;
wsEncodeFunc encode;
wsDecodeFunc decode;
} ws_ctx_t;
enum
{
WS_OPCODE_CONTINUATION = 0x0,
WS_OPCODE_TEXT_FRAME,
WS_OPCODE_BINARY_FRAME,
WS_OPCODE_CLOSE = 0x8,
WS_OPCODE_PING,
WS_OPCODE_PONG
};
#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_HIXIE "HTTP/1.1 101 Web Socket Protocol Handshake\r\n\
Upgrade: WebSocket\r\n\
Connection: Upgrade\r\n\
%sWebSocket-Origin: %s\r\n\
%sWebSocket-Location: %s://%s%s\r\n\
%sWebSocket-Protocol: %s\r\n\
\r\n%s"
#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);
void webSocketsGenMd5(char * target, char *key1, char *key2, char *key3);
static int webSocketsEncodeHybi(rfbClientPtr cl, const char *src, int len, char **dst);
static int webSocketsEncodeHixie(rfbClientPtr cl, const char *src, int len, char **dst);
static int webSocketsDecodeHybi(rfbClientPtr cl, char *dst, int len);
static int webSocketsDecodeHixie(rfbClientPtr cl, char *dst, int len);
static void hybiDecodeCleanup(ws_ctx_t *wsctx);
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;
}
}
if (!(path && host && (origin || sec_ws_origin))) {
rfbErr("webSocketsHandshake: incomplete client handshake\n");
free(response);
free(buf);
return FALSE;
}
if ((protocol) && (strstr(protocol, "binary"))) {
if (! sec_ws_version) {
rfbErr("webSocketsHandshake: 'binary' protocol not supported with Hixie\n");
free(response);
free(buf);
return FALSE;
}
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.
*/
if (sec_ws_version) {
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);
} else {
/* older hixie handshake, this could be removed if
* a final standard is established */
if (!(key1 && key2 && key3)) {
rfbLog(" - WebSockets client version hixie-75\n");
prefix[0] = '\0';
trailer[0] = '\0';
} else {
rfbLog(" - WebSockets client version hixie-76\n");
snprintf(prefix, 5, "Sec-");
webSocketsGenMd5(trailer, key1, key2, key3);
}
len = snprintf(response, WEBSOCKETS_MAX_HANDSHAKE_LEN,
SERVER_HANDSHAKE_HIXIE, prefix, origin, prefix, scheme,
host, path, prefix, protocol, trailer);
}
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));
if (sec_ws_version) {
wsctx->version = WEBSOCKETS_VERSION_HYBI;
wsctx->encode = webSocketsEncodeHybi;
wsctx->decode = webSocketsDecodeHybi;
} else {
wsctx->version = WEBSOCKETS_VERSION_HIXIE;
wsctx->encode = webSocketsEncodeHixie;
wsctx->decode = webSocketsDecodeHixie;
}
wsctx->base64 = base64;
hybiDecodeCleanup(wsctx);
cl->wsctx = (wsCtx *)wsctx;
return TRUE;
}
void
webSocketsGenMd5(char * target, char *key1, char *key2, char *key3)
{
unsigned int i, spaces1 = 0, spaces2 = 0;
unsigned long num1 = 0, num2 = 0;
unsigned char buf[17];
struct iovec iov[1];
for (i=0; i < strlen(key1); i++) {
if (key1[i] == ' ') {
spaces1 += 1;
}
if ((key1[i] >= 48) && (key1[i] <= 57)) {
num1 = num1 * 10 + (key1[i] - 48);
}
}
num1 = num1 / spaces1;
for (i=0; i < strlen(key2); i++) {
if (key2[i] == ' ') {
spaces2 += 1;
}
if ((key2[i] >= 48) && (key2[i] <= 57)) {
num2 = num2 * 10 + (key2[i] - 48);
}
}
num2 = num2 / spaces2;
/* Pack it big-endian */
buf[0] = (num1 & 0xff000000) >> 24;
buf[1] = (num1 & 0xff0000) >> 16;
buf[2] = (num1 & 0xff00) >> 8;
buf[3] = num1 & 0xff;
buf[4] = (num2 & 0xff000000) >> 24;
buf[5] = (num2 & 0xff0000) >> 16;
buf[6] = (num2 & 0xff00) >> 8;
buf[7] = num2 & 0xff;
strncpy((char *)buf+8, key3, 8);
buf[16] = '\0';
iov[0].iov_base = buf;
iov[0].iov_len = 16;
digestmd5(iov, 1, target);
target[16] = '\0';
return;
}
static int
webSocketsEncodeHixie(rfbClientPtr cl, const char *src, int len, char **dst)
{
int sz = 0;
ws_ctx_t *wsctx = (ws_ctx_t *)cl->wsctx;
wsctx->codeBufEncode[sz++] = '\x00';
len = b64_ntop((unsigned char *)src, len, wsctx->codeBufEncode+sz, sizeof(wsctx->codeBufEncode) - (sz + 1));
if (len < 0) {
return len;
}
sz += len;
wsctx->codeBufEncode[sz++] = '\xff';
*dst = wsctx->codeBufEncode;
return sz;
}
static int
ws_read(rfbClientPtr cl, char *buf, int len)
{
int n;
if (cl->sslctx) {
n = rfbssl_read(cl, buf, len);
} else {
n = read(cl->sock, buf, len);
}
return n;
}
static int
ws_peek(rfbClientPtr cl, char *buf, int len)
{
int n;
if (cl->sslctx) {
n = rfbssl_peek(cl, buf, len);
} else {
while (-1 == (n = recv(cl->sock, buf, len, MSG_PEEK))) {
if (errno != EAGAIN)
break;
}
}
return n;
}
static int
webSocketsDecodeHixie(rfbClientPtr cl, char *dst, int len)
{
int retlen = 0, n, i, avail, modlen, needlen;
char *buf, *end = NULL;
ws_ctx_t *wsctx = (ws_ctx_t *)cl->wsctx;
buf = wsctx->codeBufDecode;
n = ws_peek(cl, buf, len*2+2);
if (n <= 0) {
/* save errno because rfbErr() will tamper it */
int olderrno = errno;
rfbErr("%s: peek (%d) %m\n", __func__, errno);
errno = olderrno;
return n;
}
/* Base64 encoded WebSockets stream */
if (buf[0] == '\xff') {
i = ws_read(cl, buf, 1); /* Consume marker */
buf++;
n--;
}
if (n == 0) {
errno = EAGAIN;
return -1;
}
if (buf[0] == '\x00') {
i = ws_read(cl, buf, 1); /* Consume marker */
buf++;
n--;
}
if (n == 0) {
errno = EAGAIN;
return -1;
}
/* end = memchr(buf, '\xff', len*2+2); */
end = memchr(buf, '\xff', n);
if (!end) {
end = buf + n;
}
avail = end - buf;
len -= wsctx->carrylen;
/* Determine how much base64 data we need */
modlen = len + (len+2)/3;
needlen = modlen;
if (needlen % 4) {
needlen += 4 - (needlen % 4);
}
if (needlen > avail) {
/* rfbLog("Waiting for more base64 data\n"); */
errno = EAGAIN;
return -1;
}
/* Any carryover from previous decode */
for (i=0; i < wsctx->carrylen; i++) {
/* rfbLog("Adding carryover %d\n", wsctx->carryBuf[i]); */
dst[i] = wsctx->carryBuf[i];
retlen += 1;
}
/* Decode the rest of what we need */
buf[needlen] = '\x00'; /* Replace end marker with end of string */
/* rfbLog("buf: %s\n", buf); */
n = b64_pton(buf, (unsigned char *)dst+retlen, 2+len);
if (n < len) {
rfbErr("Base64 decode error\n");
errno = EIO;
return -1;
}
retlen += n;
/* Consume the data from socket */
i = ws_read(cl, buf, needlen);
wsctx->carrylen = n - len;
retlen -= wsctx->carrylen;
for (i=0; i < wsctx->carrylen; i++) {
/* rfbLog("Saving carryover %d\n", dst[retlen + i]); */
wsctx->carryBuf[i] = dst[retlen + i];
}
/* rfbLog("<< webSocketsDecode, retlen: %d\n", retlen); */
return retlen;
}
static int
hybiRemaining(ws_ctx_t *wsctx)
{
return wsctx->nToRead - wsctx->nReadRaw;
}
static void
hybiDecodeCleanup(ws_ctx_t *wsctx)
{
wsctx->header.payloadLen = 0;
wsctx->header.mask.u = 0;
wsctx->nReadRaw = 0;
wsctx->nToRead= 0;
wsctx->carrylen = 0;
wsctx->readPos = (unsigned char *)wsctx->codeBufDecode;
wsctx->readlen = 0;
wsctx->hybiDecodeState = WS_HYBI_STATE_HEADER_PENDING;
wsctx->writePos = NULL;
rfbLog("cleaned up wsctx\n");
}
/**
* Return payload data that has been decoded/unmasked from
* a websocket frame.
*
* @param[out] dst destination buffer
* @param[in] len bytes to copy to destination buffer
* @param[in,out] wsctx internal state of decoding procedure
* @param[out] number of bytes actually written to dst buffer
* @return next hybi decoding state
*/
static int
hybiReturnData(char *dst, int len, ws_ctx_t *wsctx, int *nWritten)
{
int nextState = WS_HYBI_STATE_ERR;
/* if we have something already decoded copy and return */
if (wsctx->readlen > 0) {
/* simply return what we have */
if (wsctx->readlen > len) {
rfbLog("copy to %d bytes to dst buffer; readPos=%p, readLen=%d\n", len, wsctx->readPos, wsctx->readlen);
memcpy(dst, wsctx->readPos, len);
*nWritten = len;
wsctx->readlen -= len;
wsctx->readPos += len;
nextState = WS_HYBI_STATE_DATA_AVAILABLE;
} else {
rfbLog("copy to %d bytes to dst buffer; readPos=%p, readLen=%d\n", wsctx->readlen, wsctx->readPos, wsctx->readlen);
memcpy(dst, wsctx->readPos, wsctx->readlen);
*nWritten = wsctx->readlen;
wsctx->readlen = 0;
wsctx->readPos = NULL;
if (hybiRemaining(wsctx) == 0) {
nextState = WS_HYBI_STATE_FRAME_COMPLETE;
} else {
nextState = WS_HYBI_STATE_DATA_NEEDED;
}
}
rfbLog("after copy: readPos=%p, readLen=%d\n", wsctx->readPos, wsctx->readlen);
} else if (wsctx->hybiDecodeState == WS_HYBI_STATE_CLOSE_REASON_PENDING) {
nextState = WS_HYBI_STATE_CLOSE_REASON_PENDING;
}
return nextState;
}
/**
* Read an RFC 6455 websocket frame (IETF hybi working group).
*
* Internal state is updated according to bytes received and the
* decoding of header information.
*
* @param[in] cl client ptr with ptr to raw socket and ws_ctx_t ptr
* @param[out] sockRet emulated recv return value
* @return next hybi decoding state; WS_HYBI_STATE_HEADER_PENDING indicates
* that the header was not received completely.
*/
static int
hybiReadHeader(rfbClientPtr cl, int *sockRet)
{
int ret;
ws_ctx_t *wsctx = (ws_ctx_t *)cl->wsctx;
char *headerDst = wsctx->codeBufDecode + wsctx->nReadRaw;
int n = WSHLENMAX - wsctx->nReadRaw;
rfbLog("header_read to %p with len=%d\n", headerDst, n);
ret = ws_read(cl, headerDst, n);
rfbLog("read %d bytes from socket\n", ret);
if (ret <= 0) {
if (-1 == ret) {
/* save errno because rfbErr() will tamper it */
int olderrno = errno;
rfbErr("%s: peek; %m\n", __func__);
errno = olderrno;
*sockRet = -1;
} else {
*sockRet = 0;
}
return WS_HYBI_STATE_ERR;
}
wsctx->nReadRaw += ret;
if (wsctx->nReadRaw < 2) {
/* cannot decode header with less than two bytes */
errno = EAGAIN;
*sockRet = -1;
return WS_HYBI_STATE_HEADER_PENDING;
}
/* first two header bytes received; interpret header data and get rest */
wsctx->header.data = (ws_header_t *)wsctx->codeBufDecode;
wsctx->header.opcode = wsctx->header.data->b0 & 0x0f;
/* fin = (header->b0 & 0x80) >> 7; */ /* not used atm */
wsctx->header.payloadLen = wsctx->header.data->b1 & 0x7f;
rfbLog("first header bytes received; opcode=%d lenbyte=%d\n", wsctx->header.opcode, wsctx->header.payloadLen);
/*
* 4.3. Client-to-Server Masking
*
* The client MUST mask all frames sent to the server. A server MUST
* close the connection upon receiving a frame with the MASK bit set to 0.
**/
if (!(wsctx->header.data->b1 & 0x80)) {
rfbErr("%s: got frame without mask ret=%d\n", __func__, ret);
errno = EIO;
*sockRet = -1;
return WS_HYBI_STATE_ERR;
}
if (wsctx->header.payloadLen < 126 && wsctx->nReadRaw >= 6) {
wsctx->header.headerLen = 2 + WS_HYBI_MASK_LEN;
wsctx->header.mask = wsctx->header.data->u.m;
} else if (wsctx->header.payloadLen == 126 && 8 <= wsctx->nReadRaw) {
wsctx->header.headerLen = 4 + WS_HYBI_MASK_LEN;
wsctx->header.payloadLen = WS_NTOH16(wsctx->header.data->u.s16.l16);
wsctx->header.mask = wsctx->header.data->u.s16.m16;
} else if (wsctx->header.payloadLen == 127 && 14 <= wsctx->nReadRaw) {
wsctx->header.headerLen = 10 + WS_HYBI_MASK_LEN;
wsctx->header.payloadLen = WS_NTOH64(wsctx->header.data->u.s64.l64);
wsctx->header.mask = wsctx->header.data->u.s64.m64;
} else {
/* Incomplete frame header, try again */
rfbErr("%s: incomplete frame header; ret=%d\n", __func__, ret);
errno = EAGAIN;
*sockRet = -1;
return WS_HYBI_STATE_HEADER_PENDING;
}
/* absolute length of frame */
wsctx->nToRead = wsctx->header.headerLen + wsctx->header.payloadLen;
/* set payload pointer just after header */
wsctx->writePos = wsctx->codeBufDecode + wsctx->nReadRaw;
wsctx->readPos = (unsigned char *)(wsctx->codeBufDecode + wsctx->header.headerLen);
rfbLog("header complete: state=%d flen=%d writeTo=%p\n", wsctx->hybiDecodeState, wsctx->nToRead, wsctx->writePos);
return WS_HYBI_STATE_DATA_NEEDED;
}
static int
hybiWsFrameComplete(ws_ctx_t *wsctx)
{
return wsctx != NULL && hybiRemaining(wsctx) == 0;
}
static char *
hybiPayloadStart(ws_ctx_t *wsctx)
{
return wsctx->codeBufDecode + wsctx->header.headerLen;
}
/**
* Read the remaining payload bytes from associated raw socket.
*
* - try to read remaining bytes from socket
* - unmask all multiples of 4
* - if frame incomplete but some bytes are left, these are copied to
* the carry buffer
* - if opcode is TEXT: Base64-decode all unmasked received bytes
* - set state for reading decoded data
* - reset write position to begin of buffer (+ header)
* --> before we retrieve more data we let the caller clear all bytes
* from the reception buffer
* - execute return data routine
*
* Sets errno corresponding to what it gets from the underlying
* socket or EIO if some internal sanity check fails.
*
* @param[in] cl client ptr with raw socket reference
* @param[out] dst destination buffer
* @param[in] len size of destination buffer
* @param[out] sockRet emulated recv return value
* @return next hybi decode state
*/
static int
hybiReadAndDecode(rfbClientPtr cl, char *dst, int len, int *sockRet)
{
int n;
int i;
int toReturn;
int toDecode;
int bufsize;
int nextRead;
unsigned char *data;
uint32_t *data32;
ws_ctx_t *wsctx = (ws_ctx_t *)cl->wsctx;
/* if data was carried over, copy to start of buffer */
memcpy(wsctx->writePos, wsctx->carryBuf, wsctx->carrylen);
wsctx->writePos += wsctx->carrylen;
/* -1 accounts for potential '\0' terminator for base64 decoding */
bufsize = wsctx->codeBufDecode + ARRAYSIZE(wsctx->codeBufDecode) - wsctx->writePos - 1;
if (hybiRemaining(wsctx) > bufsize) {
nextRead = bufsize;
} else {
nextRead = hybiRemaining(wsctx);
}
rfbLog("calling read with buf=%p and len=%d (decodebuf=%p headerLen=%d\n)", wsctx->writePos, nextRead, wsctx->codeBufDecode, wsctx->header.headerLen);
if (wsctx->nReadRaw < wsctx->nToRead) {
/* decode more data */
if (-1 == (n = ws_read(cl, wsctx->writePos, nextRead))) {
int olderrno = errno;
rfbErr("%s: read; %m", __func__);
errno = olderrno;
*sockRet = -1;
return WS_HYBI_STATE_ERR;
} else if (n == 0) {
*sockRet = 0;
return WS_HYBI_STATE_ERR;
}
wsctx->nReadRaw += n;
rfbLog("read %d bytes from socket; nRead=%d\n", n, wsctx->nReadRaw);
} else {
n = 0;
}
wsctx->writePos += n;
if (wsctx->nReadRaw >= wsctx->nToRead) {
if (wsctx->nReadRaw > wsctx->nToRead) {
rfbErr("%s: internal error, read past websocket frame", __func__);
errno=EIO;
*sockRet = -1;
return WS_HYBI_STATE_ERR;
}
}
toDecode = wsctx->writePos - hybiPayloadStart(wsctx);
rfbLog("toDecode=%d from n=%d carrylen=%d headerLen=%d\n", toDecode, n, wsctx->carrylen, wsctx->header.headerLen);
if (toDecode < 0) {
rfbErr("%s: internal error; negative number of bytes to decode: %d", __func__, toDecode);
errno=EIO;
*sockRet = -1;
return WS_HYBI_STATE_ERR;
}
/* for a possible base64 decoding, we decode multiples of 4 bytes until
* the whole frame is received and carry over any remaining bytes in the carry buf*/
data = (unsigned char *)hybiPayloadStart(wsctx);
data32= (uint32_t *)data;
for (i = 0; i < (toDecode >> 2); i++) {
data32[i] ^= wsctx->header.mask.u;
}
rfbLog("mask decoding; i=%d toDecode=%d\n", i, toDecode);
if (wsctx->hybiDecodeState == WS_HYBI_STATE_FRAME_COMPLETE) {
/* process the remaining bytes (if any) */
for (i*=4; i < toDecode; i++) {
data[i] ^= wsctx->header.mask.c[i % 4];
}
/* all data is here, no carrying */
wsctx->carrylen = 0;
} else {
/* carry over remaining, non-multiple-of-four bytes */
wsctx->carrylen = toDecode - (i * 4);
if (wsctx->carrylen < 0 || wsctx->carrylen > ARRAYSIZE(wsctx->carryBuf)) {
rfbErr("%s: internal error, invalid carry over size: carrylen=%d, toDecode=%d, i=%d", __func__, wsctx->carrylen, toDecode, i);
*sockRet = -1;
errno = EIO;
return WS_HYBI_STATE_ERR;
}
rfbLog("carrying over %d bytes from %p to %p\n", wsctx->carrylen, wsctx->writePos + (i * 4), wsctx->carryBuf);
memcpy(wsctx->carryBuf, data + (i * 4), wsctx->carrylen);
}
toReturn = toDecode - wsctx->carrylen;
switch (wsctx->header.opcode) {
case WS_OPCODE_CLOSE:
/* this data is not returned as payload data */
if (hybiWsFrameComplete(wsctx)) {
rfbLog("got closure, reason %d\n", WS_NTOH16(((uint16_t *)data)[0]));
errno = ECONNRESET;
*sockRet = -1;
return WS_HYBI_STATE_FRAME_COMPLETE;
} else {
rfbErr("%s: close reason with long frame not supported", __func__);
errno = EIO;
*sockRet = -1;
return WS_HYBI_STATE_ERR;
}
break;
case WS_OPCODE_TEXT_FRAME:
data[toReturn] = '\0';
rfbLog("Initiate Base64 decoding in %p with max size %d and '\\0' at %p\n", data, bufsize, data + toReturn);
if (-1 == (wsctx->readlen = b64_pton((char *)data, data, bufsize))) {
rfbErr("Base64 decode error in %s; data=%p bufsize=%d", __func__, data, bufsize);
rfbErr("%s: Base64 decode error; %m\n", __func__);
}
wsctx->writePos = hybiPayloadStart(wsctx);
break;
case WS_OPCODE_BINARY_FRAME:
wsctx->readlen = toReturn;
wsctx->writePos = hybiPayloadStart(wsctx);
break;
default:
rfbErr("%s: unhandled opcode %d, b0: %02x, b1: %02x\n", __func__, (int)wsctx->header.opcode, wsctx->header.data->b0, wsctx->header.data->b1);
}
wsctx->readPos = data;
return hybiReturnData(dst, len, wsctx, sockRet);
}
/**
* Read function for websocket-socket emulation.
*
* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-------+-+-------------+-------------------------------+
* |F|R|R|R| opcode|M| Payload len | Extended payload length |
* |I|S|S|S| (4) |A| (7) | (16/64) |
* |N|V|V|V| |S| | (if payload len==126/127) |
* | |1|2|3| |K| | |
* +-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
* | Extended payload length continued, if payload len == 127 |
* + - - - - - - - - - - - - - - - +-------------------------------+
* | |Masking-key, if MASK set to 1 |
* +-------------------------------+-------------------------------+
* | Masking-key (continued) | Payload Data |
* +-------------------------------- - - - - - - - - - - - - - - - +
* : Payload Data continued ... :
* + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
* | Payload Data continued ... |
* +---------------------------------------------------------------+
*
* Using the decode buffer, this function:
* - reads the complete header from the underlying socket
* - reads any remaining data bytes
* - unmasks the payload data using the provided mask
* - decodes Base64 encoded text data
* - copies len bytes of decoded payload data into dst
*
* Emulates a read call on a socket.
*/
static int
webSocketsDecodeHybi(rfbClientPtr cl, char *dst, int len)
{
int result = -1;
ws_ctx_t *wsctx = (ws_ctx_t *)cl->wsctx;
/* int fin; */ /* not used atm */
/* rfbLog(" <== %s[%d]: %d cl: %p, wsctx: %p-%p (%d)\n", __func__, gettid(), len, cl, wsctx, (char *)wsctx + sizeof(ws_ctx_t), sizeof(ws_ctx_t)); */
rfbLog("%s_enter: len=%d; "
"CTX: readlen=%d readPos=%p "
"writeTo=%p "
"state=%d toRead=%d remaining=%d "
" nReadRaw=%d carrylen=%d carryBuf=%p\n",
__func__, len,
wsctx->readlen, wsctx->readPos,
wsctx->writePos,
wsctx->hybiDecodeState, wsctx->nToRead, hybiRemaining(wsctx),
wsctx->nReadRaw, wsctx->carrylen, wsctx->carryBuf);
switch (wsctx->hybiDecodeState){
case WS_HYBI_STATE_HEADER_PENDING:
wsctx->hybiDecodeState = hybiReadHeader(cl, &result);
if (wsctx->hybiDecodeState == WS_HYBI_STATE_ERR) {
goto spor;
}
if (wsctx->hybiDecodeState != WS_HYBI_STATE_HEADER_PENDING) {
/* when header is complete, try to read some more data */
wsctx->hybiDecodeState = hybiReadAndDecode(cl, dst, len, &result);
}
break;
case WS_HYBI_STATE_DATA_AVAILABLE:
wsctx->hybiDecodeState = hybiReturnData(dst, len, wsctx, &result);
break;
case WS_HYBI_STATE_DATA_NEEDED:
wsctx->hybiDecodeState = hybiReadAndDecode(cl, dst, len, &result);
break;
case WS_HYBI_STATE_CLOSE_REASON_PENDING:
wsctx->hybiDecodeState = hybiReadAndDecode(cl, dst, len, &result);
break;
default:
/* invalid state */
rfbErr("%s: called with invalid state %d\n", wsctx->hybiDecodeState);
result = -1;
errno = EIO;
wsctx->hybiDecodeState = WS_HYBI_STATE_ERR;
}
/* single point of return, if someone has questions :-) */
spor:
/* rfbLog("%s: ret: %d/%d\n", __func__, result, len); */
if (wsctx->hybiDecodeState == WS_HYBI_STATE_FRAME_COMPLETE) {
rfbLog("frame received successfully, cleaning up: read=%d hlen=%d plen=%d\n", wsctx->header.nRead, wsctx->header.headerLen, wsctx->header.payloadLen);
/* frame finished, cleanup state */
hybiDecodeCleanup(wsctx);
} else if (wsctx->hybiDecodeState == WS_HYBI_STATE_ERR) {
hybiDecodeCleanup(wsctx);
}
rfbLog("%s_exit: len=%d; "
"CTX: readlen=%d readPos=%p "
"writePos=%p "
"state=%d toRead=%d remaining=%d "
"nRead=%d carrylen=%d carryBuf=%p "
"result=%d\n",
__func__, len,
wsctx->readlen, wsctx->readPos,
wsctx->writePos,
wsctx->hybiDecodeState, wsctx->nToRead, hybiRemaining(wsctx),
wsctx->nReadRaw, wsctx->carrylen, wsctx->carryBuf,
result);
return result;
}
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 ((ws_ctx_t *)cl->wsctx)->encode(cl, src, len, dst);
}
int
webSocketsDecode(rfbClientPtr cl, char *dst, int len)
{
return ((ws_ctx_t *)cl->wsctx)->decode(cl, dst, len);
}
/* returns TRUE if client sent a close frame or a single 'end of frame'
* marker was received, FALSE otherwise
*
* Note: This is a Hixie-only hack!
**/
rfbBool
webSocketCheckDisconnect(rfbClientPtr cl)
{
ws_ctx_t *wsctx = (ws_ctx_t *)cl->wsctx;
/* With Base64 encoding we need at least 4 bytes */
char peekbuf[4];
int n;
if (wsctx->version == WEBSOCKETS_VERSION_HYBI)
return FALSE;
if (cl->sslctx)
n = rfbssl_peek(cl, peekbuf, 4);
else
n = recv(cl->sock, peekbuf, 4, MSG_PEEK);
if (n <= 0) {
if (n != 0)
rfbErr("%s: peek; %m", __func__);
rfbCloseClient(cl);
return TRUE;
}
if (peekbuf[0] == '\xff') {
int doclose = 0;
/* Make sure we don't miss a client disconnect on an end frame
* marker. Because we use a peek buffer in some cases it is not
* applicable to wait for more data per select(). */
switch (n) {
case 3:
if (peekbuf[1] == '\xff' && peekbuf[2] == '\x00')
doclose = 1;
break;
case 2:
if (peekbuf[1] == '\x00')
doclose = 1;
break;
default:
return FALSE;
}
if (cl->sslctx)
n = rfbssl_read(cl, peekbuf, n);
else
n = read(cl->sock, peekbuf, n);
if (doclose) {
rfbErr("%s: websocket close frame received\n", __func__);
rfbCloseClient(cl);
}
return TRUE;
}
return FALSE;
}
/* 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);
}
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