/// <summary> /// Reads a varint from the input one byte at a time, so that it does not /// read any bytes after the end of the varint. If you simply wrapped the /// stream in a CodedInputStream and used ReadRawVarint32(Stream) /// then you would probably end up reading past the end of the varint since /// CodedInputStream buffers its input. /// </summary> /// <param name="input"></param> /// <returns></returns> public static uint ReadRawVarint32(Stream input) { int result = 0; int offset = 0; for (; offset < 32; offset += 7) { int b = input.ReadByte(); if (b == -1) { throw InvalidProtocolBufferException.TruncatedMessage(); } result |= (b & 0x7f) << offset; if ((b & 0x80) == 0) { return((uint)result); } } // Keep reading up to 64 bits. for (; offset < 64; offset += 7) { int b = input.ReadByte(); if (b == -1) { throw InvalidProtocolBufferException.TruncatedMessage(); } if ((b & 0x80) == 0) { return((uint)result); } } throw InvalidProtocolBufferException.MalformedVarint(); }
/// <summary> /// Validates that the specified size doesn't exceed the current limit. If it does then remaining bytes /// are skipped and an error is thrown. /// </summary> private static void ValidateCurrentLimit(ref ReadOnlySpan <byte> buffer, ref ParserInternalState state, int size) { if (state.totalBytesRetired + state.bufferPos + size > state.currentLimit) { // Read to the end of the stream (up to the current limit) anyway. SkipRawBytes(ref buffer, ref state, state.currentLimit - state.totalBytesRetired - state.bufferPos); // Then fail. throw InvalidProtocolBufferException.TruncatedMessage(); } }
private bool RefillFromReadOnlySequence(ref ReadOnlySpan <byte> buffer, ref ParserInternalState state, bool mustSucceed) { CheckCurrentBufferIsEmpty(ref state); if (state.totalBytesRetired + state.bufferSize == state.currentLimit) { // Oops, we hit a limit. if (mustSucceed) { throw InvalidProtocolBufferException.TruncatedMessage(); } else { return(false); } } state.totalBytesRetired += state.bufferSize; state.bufferPos = 0; state.bufferSize = 0; while (readOnlySequenceEnumerator.MoveNext()) { buffer = readOnlySequenceEnumerator.Current.Span; state.bufferSize = buffer.Length; if (buffer.Length != 0) { break; } } if (state.bufferSize == 0) { if (mustSucceed) { throw InvalidProtocolBufferException.TruncatedMessage(); } else { return(false); } } else { RecomputeBufferSizeAfterLimit(ref state); int totalBytesRead = state.totalBytesRetired + state.bufferSize + state.bufferSizeAfterLimit; if (totalBytesRead < 0 || totalBytesRead > state.sizeLimit) { throw InvalidProtocolBufferException.SizeLimitExceeded(); } return(true); } }
private bool RefillFromCodedInputStream(ref ReadOnlySpan <byte> buffer, ref ParserInternalState state, bool mustSucceed) { CheckCurrentBufferIsEmpty(ref state); if (state.totalBytesRetired + state.bufferSize == state.currentLimit) { // Oops, we hit a limit. if (mustSucceed) { throw InvalidProtocolBufferException.TruncatedMessage(); } else { return(false); } } Stream input = codedInputStream.InternalInputStream; state.totalBytesRetired += state.bufferSize; state.bufferPos = 0; state.bufferSize = (input == null) ? 0 : input.Read(codedInputStream.InternalBuffer, 0, buffer.Length); if (state.bufferSize < 0) { throw new InvalidOperationException("Stream.Read returned a negative count"); } if (state.bufferSize == 0) { if (mustSucceed) { throw InvalidProtocolBufferException.TruncatedMessage(); } else { return(false); } } else { RecomputeBufferSizeAfterLimit(ref state); int totalBytesRead = state.totalBytesRetired + state.bufferSize + state.bufferSizeAfterLimit; if (totalBytesRead < 0 || totalBytesRead > state.sizeLimit) { throw InvalidProtocolBufferException.SizeLimitExceeded(); } return(true); } }
/// <summary> /// Sets currentLimit to (current position) + byteLimit. This is called /// when descending into a length-delimited embedded message. The previous /// limit is returned. /// </summary> /// <returns>The old limit.</returns> public static int PushLimit(ref ParserInternalState state, int byteLimit) { if (byteLimit < 0) { throw InvalidProtocolBufferException.NegativeSize(); } byteLimit += state.totalBytesRetired + state.bufferPos; int oldLimit = state.currentLimit; if (byteLimit > oldLimit) { throw InvalidProtocolBufferException.TruncatedMessage(); } state.currentLimit = byteLimit; RecomputeBufferSizeAfterLimit(ref state); return(oldLimit); }
public static void ReadMessage(ref ParseContext ctx, IMessage message) { int length = ParsingPrimitives.ParseLength(ref ctx.buffer, ref ctx.state); if (ctx.state.recursionDepth >= ctx.state.recursionLimit) { throw InvalidProtocolBufferException.RecursionLimitExceeded(); } int oldLimit = SegmentedBufferHelper.PushLimit(ref ctx.state, length); ++ctx.state.recursionDepth; ReadRawMessage(ref ctx, message); CheckReadEndOfStreamTag(ref ctx.state); // Check that we've read exactly as much data as expected. if (!SegmentedBufferHelper.IsReachedLimit(ref ctx.state)) { throw InvalidProtocolBufferException.TruncatedMessage(); } --ctx.state.recursionDepth; SegmentedBufferHelper.PopLimit(ref ctx.state, oldLimit); }
/// <summary> /// Skip a group. /// </summary> public static void SkipGroup(ref ReadOnlySpan <byte> buffer, ref ParserInternalState state, uint startGroupTag) { // Note: Currently we expect this to be the way that groups are read. We could put the recursion // depth changes into the ReadTag method instead, potentially... state.recursionDepth++; if (state.recursionDepth >= state.recursionLimit) { throw InvalidProtocolBufferException.RecursionLimitExceeded(); } uint tag; while (true) { tag = ParsingPrimitives.ParseTag(ref buffer, ref state); if (tag == 0) { throw InvalidProtocolBufferException.TruncatedMessage(); } // Can't call SkipLastField for this case- that would throw. if (WireFormat.GetTagWireType(tag) == WireFormat.WireType.EndGroup) { break; } // This recursion will allow us to handle nested groups. SkipLastField(ref buffer, ref state); } int startField = WireFormat.GetTagFieldNumber(startGroupTag); int endField = WireFormat.GetTagFieldNumber(tag); if (startField != endField) { throw new InvalidProtocolBufferException( $"Mismatched end-group tag. Started with field {startField}; ended with field {endField}"); } state.recursionDepth--; }