dotnet/wpf · error · ArgumentException

ISF size if greater then maximum stream size

Error message

ISF size if greater then maximum stream size

What it means

For variable-size attribute payloads, DecodeAsISF reads a length prefix (adds one via cbInSize++), then checks that the resulting payload size still fits within the remaining maximumStreamSize. If cbInSize exceeds it, ArgumentException with 'ISF size if greater then maximum stream size' is thrown, protecting against oversized/corrupt size fields.

Solutions

  1. Pass the true full stream length as maximumStreamSize
  2. Validate stream integrity/length before decoding
  3. Try-catch the decode and treat failure as corrupt input
  4. Regenerate the ISF from the original ink source

Example fix

// before
uint budget = 1024; // arbitrary
DrawingAttributeSerializer.DecodeAsISF(stream, guidList, budget);
// after
uint budget = (uint)stream.Length; // real stream size
DrawingAttributeSerializer.DecodeAsISF(stream, guidList, budget);
Defensive patterns

Strategy: try-catch

Validate before calling

// pre-check budget
if (!stream.CanSeek || stream.Length == 0) throw new InvalidDataException("empty or non-seekable ISF stream");

Try / catch

try { DrawingAttributeSerializer.DecodeAsISF(stream, guidList, maxSize); }
catch (ArgumentException) { /* treat stream as corrupt; reject or quarantine */ }

Prevention

When it happens

Trigger: Decoding ISF where a size prefix (plus one byte) exceeds the remaining maximumStreamSize — truncated files, malicious streams with inflated lengths, or a caller-supplied maximumStreamSize smaller than the real data.

Common situations: Untrusted ISF input (fuzzing/malware analysis); files damaged in transfer; incorrectly computed stream budgets in calling code.

Understand the failure class

Background: "File too large" / "file size exceeds limit" errors: why libraries cap file sizes and how to fix them — this error's family across 46 libraries.

Related errors

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/4ab0a5ed22620b9a. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationCore/MS/internal/Ink/InkSerializedFormat/DrawingAttributeSerializer.cs:218

                    cb = SerializationHelper.Decode (stream, out dw);
                    _size = (double)dw;
                    maximumStreamSize -= cb;
                    if (maximumStreamSize > 0)
                    {
                        cb = SerializationHelper.Decode (stream, out dw);
                        maximumStreamSize -= cb;
                        if (KnownTagCache.KnownTagIndex.Mantissa == (KnownTagCache.KnownTagIndex)dw)
                        {
                            uint cbInSize;
                            // First thing that is in there is maximumStreamSize of the data
                            cb = SerializationHelper.Decode (stream, out cbInSize);
                            maximumStreamSize -= cb;

                            // in maximumStreamSize is one more than the decoded no
                            cbInSize++;
                            if (cbInSize > maximumStreamSize)
                            {
                                throw new ArgumentException(StrokeCollectionSerializer.ISFDebugMessage("ISF size if greater then maximum stream size"));
                            }
                            byte[] in_data = new byte[cbInSize];
							
                            uint bytesRead = (uint) stream.Read (in_data, 0, (int)cbInSize);
                            if (cbInSize != bytesRead)
                            {
                                throw new ArgumentException(StrokeCollectionSerializer.ISFDebugMessage("Read different size from stream then expected"));
                            }

                            byte[] out_buffer = Compressor.DecompressPropertyData (in_data);
                            using (MemoryStream localStream = new MemoryStream(out_buffer))
                            using (BinaryReader rdr = new BinaryReader(localStream))
                            {
                                short sFraction = rdr.ReadInt16();
                                _size += (double)(sFraction / DrawingAttributes.StylusPrecision);

                                maximumStreamSize -= cbInSize;
			                }

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