private void InitializeStreamReaders(ref MemoryBlock metadataRoot, StreamHeader[] streamHeaders, out MemoryBlock metadataTableStream)
{
metadataTableStream = default(MemoryBlock);
foreach (StreamHeader streamHeader in streamHeaders)
{
switch (streamHeader.Name)
{
case COR20Constants.StringStreamName:
if (metadataRoot.Length < streamHeader.Offset + streamHeader.Size)
{
throw new BadImageFormatException(MetadataResources.NotEnoughSpaceForStringStream);
}
this.StringStream = new StringStreamReader(metadataRoot.GetMemoryBlockAt((int)streamHeader.Offset, streamHeader.Size), this.metadataKind);
break;
case COR20Constants.BlobStreamName:
if (metadataRoot.Length < streamHeader.Offset + streamHeader.Size)
{
throw new BadImageFormatException(MetadataResources.NotEnoughSpaceForBlobStream);
}
this.BlobStream = new BlobStreamReader(metadataRoot.GetMemoryBlockAt((int)streamHeader.Offset, streamHeader.Size), this.metadataKind);
break;
case COR20Constants.GUIDStreamName:
if (metadataRoot.Length < streamHeader.Offset + streamHeader.Size)
{
throw new BadImageFormatException(MetadataResources.NotEnoughSpaceForGUIDStream);
}
this.GuidStream = new GuidStreamReader(metadataRoot.GetMemoryBlockAt((int)streamHeader.Offset, streamHeader.Size));
break;
case COR20Constants.UserStringStreamName:
if (metadataRoot.Length < streamHeader.Offset + streamHeader.Size)
{
throw new BadImageFormatException(MetadataResources.NotEnoughSpaceForBlobStream);
}
this.UserStringStream = new UserStringStreamReader(metadataRoot.GetMemoryBlockAt((int)streamHeader.Offset, streamHeader.Size));
break;
case COR20Constants.CompressedMetadataTableStreamName:
if (metadataRoot.Length < streamHeader.Offset + streamHeader.Size)
{
throw new BadImageFormatException(MetadataResources.NotEnoughSpaceForMetadataStream);
}
this.metadataStreamKind = MetadataStreamKind.Compressed;
metadataTableStream = metadataRoot.GetMemoryBlockAt((int)streamHeader.Offset, streamHeader.Size);
break;
case COR20Constants.UncompressedMetadataTableStreamName:
if (metadataRoot.Length < streamHeader.Offset + streamHeader.Size)
{
throw new BadImageFormatException(MetadataResources.NotEnoughSpaceForMetadataStream);
}
this.metadataStreamKind = MetadataStreamKind.Uncompressed;
metadataTableStream = metadataRoot.GetMemoryBlockAt((int)streamHeader.Offset, streamHeader.Size);
break;
case COR20Constants.MinimalDeltaMetadataTableStreamName:
if (metadataRoot.Length < streamHeader.Offset + streamHeader.Size)
{
throw new BadImageFormatException(MetadataResources.NotEnoughSpaceForMetadataStream);
}
// the content of the stream is ignored
this.IsMinimalDelta = true;
break;
default:
// Skip unknown streams. Some obfuscators insert invalid streams.
continue;
}
}
if (IsMinimalDelta && metadataStreamKind != MetadataStreamKind.Uncompressed)
{
throw new BadImageFormatException(MetadataResources.InvalidMetadataStreamFormat);
}
}
/// <summary>
/// Reads stream headers described in Ecma-335 24.2.2 Stream header
/// </summary>
private StreamHeader[] ReadStreamHeaders(ref BlobReader memReader)
{
// storage header:
memReader.ReadUInt16();
int streamCount = memReader.ReadInt16();
var streamHeaders = new StreamHeader[streamCount];
for (int i = 0; i < streamHeaders.Length; i++)
{
if (memReader.RemainingBytes < COR20Constants.MinimumSizeofStreamHeader)
{
throw new BadImageFormatException(MetadataResources.StreamHeaderTooSmall);
}
streamHeaders[i].Offset = memReader.ReadUInt32();
streamHeaders[i].Size = memReader.ReadInt32();
streamHeaders[i].Name = memReader.ReadUtf8NullTerminated();
bool aligned = memReader.TryAlign(4);
if (!aligned || memReader.RemainingBytes == 0)
{
throw new BadImageFormatException(MetadataResources.NotEnoughSpaceForStreamHeaderName);
}
}
return streamHeaders;
}
