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TightDecoder: bound rectangle area to prevent OOM from a malicious server #2132

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TightDecoder: bound rectangle area to prevent OOM from a malicious server #2132

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8 changes: 7 additions & 1 deletion common/rfb/TightDecoder.cxx
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Original file line number Diff line number Diff line change
Expand Up @@ -46,6 +46,10 @@ using namespace rfb;
static const int TIGHT_MAX_WIDTH = 2048;
static const int TIGHT_MIN_TO_COMPRESS = 12;

// Keep temporary decompression and pixel translation buffers bounded.
// This matches the size limit used by BufferedOutStream.
static const uint64_t TIGHT_MAX_DATA_SIZE = 32 * 1024 * 1024;

TightDecoder::TightDecoder()
: Decoder(DecoderPartiallyOrdered), readState(IDLE)
{
Expand Down Expand Up @@ -104,7 +108,9 @@ bool TightDecoder::readRect(const core::Rect& r, rdr::InStream* is,
// FIXME: This check should be for all Tight types, but TigerVNC
// servers until 1.16.0 were buggy and sent larger rects for
// fill type rectangles.
if (r.width() > TIGHT_MAX_WIDTH)
if ((r.width() > TIGHT_MAX_WIDTH) ||
((uint64_t)r.width() * r.height() >
TIGHT_MAX_DATA_SIZE / (server.pf().bpp / 8)))
throw protocol_error(_("Too large Tight rectangle"));

// "JPEG" compression type.
Expand Down