mirror of
https://github.com/kasmtech/KasmVNC.git
synced 2024-12-25 16:18:53 +01:00
3282836baf
Move the checks around to avoid missing cases where we might access memory that is no longer valid. Also avoid touching the underlying stream implicitly (e.g. via the destructor) as it might also no longer be valid. A malicious server could theoretically use this for remote code execution in the client. Issue found by Pavel Cheremushkin from Kaspersky Lab
458 lines
10 KiB
C++
458 lines
10 KiB
C++
/* Copyright (C) 2000-2003 Constantin Kaplinsky. All Rights Reserved.
|
|
* Copyright 2004-2005 Cendio AB.
|
|
* Copyright 2009-2015 Pierre Ossman for Cendio AB
|
|
* Copyright (C) 2011 D. R. Commander. 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.
|
|
*/
|
|
|
|
#include <assert.h>
|
|
|
|
#include <rdr/InStream.h>
|
|
#include <rdr/MemInStream.h>
|
|
#include <rdr/OutStream.h>
|
|
|
|
#include <rfb/ConnParams.h>
|
|
#include <rfb/Exception.h>
|
|
#include <rfb/PixelBuffer.h>
|
|
#include <rfb/TightConstants.h>
|
|
#include <rfb/TightDecoder.h>
|
|
|
|
using namespace rfb;
|
|
|
|
static const int TIGHT_MAX_WIDTH = 2048;
|
|
static const int TIGHT_MIN_TO_COMPRESS = 12;
|
|
|
|
#define BPP 8
|
|
#include <rfb/tightDecode.h>
|
|
#undef BPP
|
|
#define BPP 16
|
|
#include <rfb/tightDecode.h>
|
|
#undef BPP
|
|
#define BPP 32
|
|
#include <rfb/tightDecode.h>
|
|
#undef BPP
|
|
|
|
TightDecoder::TightDecoder() : Decoder(DecoderPartiallyOrdered)
|
|
{
|
|
}
|
|
|
|
TightDecoder::~TightDecoder()
|
|
{
|
|
}
|
|
|
|
void TightDecoder::readRect(const Rect& r, rdr::InStream* is,
|
|
const ConnParams& cp, rdr::OutStream* os)
|
|
{
|
|
rdr::U8 comp_ctl;
|
|
|
|
comp_ctl = is->readU8();
|
|
os->writeU8(comp_ctl);
|
|
|
|
comp_ctl >>= 4;
|
|
|
|
// "Fill" compression type.
|
|
if (comp_ctl == tightFill) {
|
|
if (cp.pf().is888())
|
|
os->copyBytes(is, 3);
|
|
else
|
|
os->copyBytes(is, cp.pf().bpp/8);
|
|
return;
|
|
}
|
|
|
|
// "JPEG" compression type.
|
|
if (comp_ctl == tightJpeg) {
|
|
rdr::U32 len;
|
|
|
|
len = readCompact(is);
|
|
os->writeOpaque32(len);
|
|
os->copyBytes(is, len);
|
|
return;
|
|
}
|
|
|
|
// Quit on unsupported compression type.
|
|
if (comp_ctl > tightMaxSubencoding)
|
|
throw Exception("TightDecoder: bad subencoding value received");
|
|
|
|
// "Basic" compression type.
|
|
|
|
int palSize = 0;
|
|
|
|
if (r.width() > TIGHT_MAX_WIDTH)
|
|
throw Exception("TightDecoder: too large rectangle (%d pixels)", r.width());
|
|
|
|
// Possible palette
|
|
if ((comp_ctl & tightExplicitFilter) != 0) {
|
|
rdr::U8 filterId;
|
|
|
|
filterId = is->readU8();
|
|
os->writeU8(filterId);
|
|
|
|
switch (filterId) {
|
|
case tightFilterPalette:
|
|
palSize = is->readU8() + 1;
|
|
os->writeU8(palSize - 1);
|
|
|
|
if (cp.pf().is888())
|
|
os->copyBytes(is, palSize * 3);
|
|
else
|
|
os->copyBytes(is, palSize * cp.pf().bpp/8);
|
|
break;
|
|
case tightFilterGradient:
|
|
if (cp.pf().bpp == 8)
|
|
throw Exception("TightDecoder: invalid BPP for gradient filter");
|
|
break;
|
|
case tightFilterCopy:
|
|
break;
|
|
default:
|
|
throw Exception("TightDecoder: unknown filter code received");
|
|
}
|
|
}
|
|
|
|
size_t rowSize, dataSize;
|
|
|
|
if (palSize != 0) {
|
|
if (palSize <= 2)
|
|
rowSize = (r.width() + 7) / 8;
|
|
else
|
|
rowSize = r.width();
|
|
} else if (cp.pf().is888()) {
|
|
rowSize = r.width() * 3;
|
|
} else {
|
|
rowSize = r.width() * cp.pf().bpp/8;
|
|
}
|
|
|
|
dataSize = r.height() * rowSize;
|
|
|
|
if (dataSize < TIGHT_MIN_TO_COMPRESS)
|
|
os->copyBytes(is, dataSize);
|
|
else {
|
|
rdr::U32 len;
|
|
|
|
len = readCompact(is);
|
|
os->writeOpaque32(len);
|
|
os->copyBytes(is, len);
|
|
}
|
|
}
|
|
|
|
bool TightDecoder::doRectsConflict(const Rect& rectA,
|
|
const void* bufferA,
|
|
size_t buflenA,
|
|
const Rect& rectB,
|
|
const void* bufferB,
|
|
size_t buflenB,
|
|
const ConnParams& cp)
|
|
{
|
|
rdr::U8 comp_ctl_a, comp_ctl_b;
|
|
|
|
assert(buflenA >= 1);
|
|
assert(buflenB >= 1);
|
|
|
|
comp_ctl_a = *(const rdr::U8*)bufferA;
|
|
comp_ctl_b = *(const rdr::U8*)bufferB;
|
|
|
|
// Resets or use of zlib pose the same problem, so merge them
|
|
if ((comp_ctl_a & 0x80) == 0x00)
|
|
comp_ctl_a |= 1 << ((comp_ctl_a >> 4) & 0x03);
|
|
if ((comp_ctl_b & 0x80) == 0x00)
|
|
comp_ctl_b |= 1 << ((comp_ctl_b >> 4) & 0x03);
|
|
|
|
if (((comp_ctl_a & 0x0f) & (comp_ctl_b & 0x0f)) != 0)
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
void TightDecoder::decodeRect(const Rect& r, const void* buffer,
|
|
size_t buflen, const ConnParams& cp,
|
|
ModifiablePixelBuffer* pb)
|
|
{
|
|
const rdr::U8* bufptr;
|
|
const PixelFormat& pf = cp.pf();
|
|
|
|
rdr::U8 comp_ctl;
|
|
|
|
bufptr = (const rdr::U8*)buffer;
|
|
|
|
assert(buflen >= 1);
|
|
|
|
comp_ctl = *bufptr;
|
|
bufptr += 1;
|
|
buflen -= 1;
|
|
|
|
// Reset zlib streams if we are told by the server to do so.
|
|
for (int i = 0; i < 4; i++) {
|
|
if (comp_ctl & 1) {
|
|
zis[i].reset();
|
|
}
|
|
comp_ctl >>= 1;
|
|
}
|
|
|
|
// "Fill" compression type.
|
|
if (comp_ctl == tightFill) {
|
|
if (pf.is888()) {
|
|
rdr::U8 pix[4];
|
|
|
|
assert(buflen >= 3);
|
|
|
|
pf.bufferFromRGB(pix, bufptr, 1);
|
|
pb->fillRect(pf, r, pix);
|
|
} else {
|
|
assert(buflen >= (size_t)pf.bpp/8);
|
|
pb->fillRect(pf, r, bufptr);
|
|
}
|
|
return;
|
|
}
|
|
|
|
// "JPEG" compression type.
|
|
if (comp_ctl == tightJpeg) {
|
|
rdr::U32 len;
|
|
|
|
int stride;
|
|
rdr::U8 *buf;
|
|
|
|
JpegDecompressor jd;
|
|
|
|
assert(buflen >= 4);
|
|
|
|
memcpy(&len, bufptr, 4);
|
|
bufptr += 4;
|
|
buflen -= 4;
|
|
|
|
// We always use direct decoding with JPEG images
|
|
buf = pb->getBufferRW(r, &stride);
|
|
jd.decompress(bufptr, len, buf, stride, r, pb->getPF());
|
|
pb->commitBufferRW(r);
|
|
return;
|
|
}
|
|
|
|
// Quit on unsupported compression type.
|
|
assert(comp_ctl <= tightMaxSubencoding);
|
|
|
|
// "Basic" compression type.
|
|
|
|
int palSize = 0;
|
|
rdr::U8 palette[256 * 4];
|
|
bool useGradient = false;
|
|
|
|
if ((comp_ctl & tightExplicitFilter) != 0) {
|
|
rdr::U8 filterId;
|
|
|
|
assert(buflen >= 1);
|
|
|
|
filterId = *bufptr;
|
|
bufptr += 1;
|
|
buflen -= 1;
|
|
|
|
switch (filterId) {
|
|
case tightFilterPalette:
|
|
assert(buflen >= 1);
|
|
|
|
palSize = *bufptr + 1;
|
|
bufptr += 1;
|
|
buflen -= 1;
|
|
|
|
if (pf.is888()) {
|
|
rdr::U8 tightPalette[palSize * 3];
|
|
|
|
assert(buflen >= sizeof(tightPalette));
|
|
|
|
memcpy(tightPalette, bufptr, sizeof(tightPalette));
|
|
bufptr += sizeof(tightPalette);
|
|
buflen -= sizeof(tightPalette);
|
|
|
|
pf.bufferFromRGB(palette, tightPalette, palSize);
|
|
} else {
|
|
size_t len;
|
|
|
|
len = palSize * pf.bpp/8;
|
|
|
|
assert(buflen >= len);
|
|
|
|
memcpy(palette, bufptr, len);
|
|
bufptr += len;
|
|
buflen -= len;
|
|
}
|
|
break;
|
|
case tightFilterGradient:
|
|
useGradient = true;
|
|
break;
|
|
case tightFilterCopy:
|
|
break;
|
|
default:
|
|
assert(false);
|
|
}
|
|
}
|
|
|
|
// Determine if the data should be decompressed or just copied.
|
|
size_t rowSize, dataSize;
|
|
rdr::U8* netbuf;
|
|
|
|
netbuf = NULL;
|
|
|
|
if (palSize != 0) {
|
|
if (palSize <= 2)
|
|
rowSize = (r.width() + 7) / 8;
|
|
else
|
|
rowSize = r.width();
|
|
} else if (pf.is888()) {
|
|
rowSize = r.width() * 3;
|
|
} else {
|
|
rowSize = r.width() * pf.bpp/8;
|
|
}
|
|
|
|
dataSize = r.height() * rowSize;
|
|
|
|
if (dataSize < TIGHT_MIN_TO_COMPRESS)
|
|
assert(buflen >= dataSize);
|
|
else {
|
|
rdr::U32 len;
|
|
int streamId;
|
|
rdr::MemInStream* ms;
|
|
|
|
assert(buflen >= 4);
|
|
|
|
memcpy(&len, bufptr, 4);
|
|
bufptr += 4;
|
|
buflen -= 4;
|
|
|
|
assert(buflen >= len);
|
|
|
|
streamId = comp_ctl & 0x03;
|
|
ms = new rdr::MemInStream(bufptr, len);
|
|
zis[streamId].setUnderlying(ms, len);
|
|
|
|
// Allocate buffer and decompress the data
|
|
netbuf = new rdr::U8[dataSize];
|
|
|
|
zis[streamId].readBytes(netbuf, dataSize);
|
|
|
|
zis[streamId].flushUnderlying();
|
|
zis[streamId].setUnderlying(NULL, 0);
|
|
delete ms;
|
|
|
|
bufptr = netbuf;
|
|
buflen = dataSize;
|
|
}
|
|
|
|
// Time to decode the actual data
|
|
bool directDecode;
|
|
|
|
rdr::U8* outbuf;
|
|
int stride;
|
|
|
|
if (pb->getPF().equal(pf)) {
|
|
// Decode directly into the framebuffer (fast path)
|
|
directDecode = true;
|
|
} else {
|
|
// Decode into an intermediate buffer and use pixel translation
|
|
directDecode = false;
|
|
}
|
|
|
|
if (directDecode)
|
|
outbuf = pb->getBufferRW(r, &stride);
|
|
else {
|
|
outbuf = new rdr::U8[r.area() * (pf.bpp/8)];
|
|
stride = r.width();
|
|
}
|
|
|
|
if (palSize == 0) {
|
|
// Truecolor data
|
|
if (useGradient) {
|
|
if (pf.is888())
|
|
FilterGradient24(bufptr, pf, (rdr::U32*)outbuf, stride, r);
|
|
else {
|
|
switch (pf.bpp) {
|
|
case 8:
|
|
assert(false);
|
|
break;
|
|
case 16:
|
|
FilterGradient(bufptr, pf, (rdr::U16*)outbuf, stride, r);
|
|
break;
|
|
case 32:
|
|
FilterGradient(bufptr, pf, (rdr::U32*)outbuf, stride, r);
|
|
break;
|
|
}
|
|
}
|
|
} else {
|
|
// Copy
|
|
rdr::U8* ptr = outbuf;
|
|
const rdr::U8* srcPtr = bufptr;
|
|
int w = r.width();
|
|
int h = r.height();
|
|
if (pf.is888()) {
|
|
while (h > 0) {
|
|
pf.bufferFromRGB(ptr, srcPtr, w);
|
|
ptr += stride * pf.bpp/8;
|
|
srcPtr += w * 3;
|
|
h--;
|
|
}
|
|
} else {
|
|
while (h > 0) {
|
|
memcpy(ptr, srcPtr, w * pf.bpp/8);
|
|
ptr += stride * pf.bpp/8;
|
|
srcPtr += w * pf.bpp/8;
|
|
h--;
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
// Indexed color
|
|
switch (pf.bpp) {
|
|
case 8:
|
|
FilterPalette((const rdr::U8*)palette, palSize,
|
|
bufptr, (rdr::U8*)outbuf, stride, r);
|
|
break;
|
|
case 16:
|
|
FilterPalette((const rdr::U16*)palette, palSize,
|
|
bufptr, (rdr::U16*)outbuf, stride, r);
|
|
break;
|
|
case 32:
|
|
FilterPalette((const rdr::U32*)palette, palSize,
|
|
bufptr, (rdr::U32*)outbuf, stride, r);
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (directDecode)
|
|
pb->commitBufferRW(r);
|
|
else {
|
|
pb->imageRect(pf, r, outbuf);
|
|
delete [] outbuf;
|
|
}
|
|
|
|
delete [] netbuf;
|
|
}
|
|
|
|
rdr::U32 TightDecoder::readCompact(rdr::InStream* is)
|
|
{
|
|
rdr::U8 b;
|
|
rdr::U32 result;
|
|
|
|
b = is->readU8();
|
|
result = (int)b & 0x7F;
|
|
if (b & 0x80) {
|
|
b = is->readU8();
|
|
result |= ((int)b & 0x7F) << 7;
|
|
if (b & 0x80) {
|
|
b = is->readU8();
|
|
result |= ((int)b & 0xFF) << 14;
|
|
}
|
|
}
|
|
|
|
return result;
|
|
}
|