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Fix heap-buffer-overflow write in PICT UnpackBits #47

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Fix heap-buffer-overflow write in PICT UnpackBits #47

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24 changes: 21 additions & 3 deletions Source/FreeImage/PluginPICT.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -756,7 +756,13 @@ UnpackBits( FreeImageIO *io, fi_handle handle, FIBITMAP* dib, MacRect* bounds, W
}
}
else {
for ( int i = 0; i < height; i++ ) {
// CWE-787: bound every PackBits write to the allocated raster.
// The RLE run length is attacker-controlled and the loop below
// advances dst without checking it against the bitmap bounds.
BYTE* const rasterStart = FreeImage_GetBits( dib );
BYTE* const rasterEnd = rasterStart +
(size_t)FreeImage_GetPitch( dib ) * FreeImage_GetHeight( dib );
for ( int i = 0; i < height; i++ ) {
// For each line do...
int linelen; // length of source line in bytes.
if (rowBytes > 250) {
Expand Down Expand Up @@ -784,16 +790,22 @@ UnpackBits( FreeImageIO *io, fi_handle handle, FIBITMAP* dib, MacRect* bounds, W

// This is slow for some formats...
if (pixelSize == 16) {
if (dst < rasterStart ||
(size_t)(rasterEnd - dst) < (size_t)len*4*PixelPerRLEUnit)
break;
expandBuf( io, handle, 1, pixelSize, dst );
for ( int k = 1; k < len; k++ ) {
for ( int k = 1; k < len; k++ ) {
// Repeat the pixel len times.
memcpy( dst+(k*4*PixelPerRLEUnit), dst, 4*PixelPerRLEUnit);
}
dst += len*4*PixelPerRLEUnit;
}
else {
if (dst < rasterStart ||
(size_t)(rasterEnd - dst) < (size_t)len*PixelPerRLEUnit)
break;
expandBuf8( io, handle, 1, pixelSize, dst );
for ( int k = 1; k < len; k++ ) {
for ( int k = 1; k < len; k++ ) {
// Repeat the expanded byte len times.
memcpy( dst+(k*PixelPerRLEUnit), dst, PixelPerRLEUnit);
}
Expand All @@ -806,10 +818,16 @@ UnpackBits( FreeImageIO *io, fi_handle handle, FIBITMAP* dib, MacRect* bounds, W
// Unpacked data
int len = (FlagCounter & 255) + 1;
if (pixelSize == 16) {
if (dst < rasterStart ||
(size_t)(rasterEnd - dst) < (size_t)len*4*PixelPerRLEUnit)
break;
expandBuf( io, handle, len, pixelSize, dst );
dst += len*4*PixelPerRLEUnit;
}
else {
if (dst < rasterStart ||
(size_t)(rasterEnd - dst) < (size_t)len*PixelPerRLEUnit)
break;
expandBuf8( io, handle, len, pixelSize, dst );
dst += len*PixelPerRLEUnit;
}
Expand Down