|
static private TruncatedMessage ( ) : |
||
| return | ||
/// <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>
internal 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>
/// Abstraction of skipping to cope with streams which can't really skip.
/// </summary>
private void SkipImpl(int amountToSkip)
{
if (input.CanSeek)
{
long previousPosition = input.Position;
input.Position += amountToSkip;
if (input.Position != previousPosition + amountToSkip)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
}
else
{
byte[] skipBuffer = new byte[Math.Min(1024, amountToSkip)];
while (amountToSkip > 0)
{
int bytesRead = input.Read(skipBuffer, 0, Math.Min(skipBuffer.Length, amountToSkip));
if (bytesRead <= 0)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
amountToSkip -= bytesRead;
}
}
}
private void SkipGroup(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...
recursionDepth++;
if (recursionDepth >= recursionLimit)
{
throw InvalidProtocolBufferException.RecursionLimitExceeded();
}
uint tag;
while (true)
{
tag = ReadTag();
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();
}
int startField = WireFormat.GetTagFieldNumber(startGroupTag);
int endField = WireFormat.GetTagFieldNumber(tag);
if (startField != endField)
{
throw new InvalidProtocolBufferException("Mismatched end-group tag. Started with fiel ended with field ");
}
recursionDepth--;
}
/// <summary>
/// Reads an embedded message field value from the stream.
/// </summary>
public void ReadMessage(Action <CodedInputStream> decoder)
{
int length = ReadLength();
if (length == 0)
{
return;
}
if (recursionDepth >= recursionLimit)
{
throw InvalidProtocolBufferException.RecursionLimitExceeded();
}
int oldLimit = PushLimit(length);
++recursionDepth;
decoder.Invoke(this);
CheckReadEndOfStreamTag();
// Check that we've read exactly as much data as expected.
if (!ReachedLimit)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
--recursionDepth;
PopLimit(oldLimit);
}
/// <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);
}
}
/// <summary>
/// Called when buffer is empty to read more bytes from the
/// input. If <paramref name="mustSucceed"/> is true, RefillBuffer() gurantees that
/// either there will be at least one byte in the buffer when it returns
/// or it will throw an exception. If <paramref name="mustSucceed"/> is false,
/// RefillBuffer() returns false if no more bytes were available.
/// </summary>
/// <param name="mustSucceed"></param>
/// <returns></returns>
private bool RefillBuffer(bool mustSucceed)
{
if (bufferPos < bufferSize)
{
throw new InvalidOperationException("RefillBuffer() called when buffer wasn't empty.");
}
if (totalBytesRetired + bufferSize == currentLimit)
{
// Oops, we hit a limit.
if (mustSucceed)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
else
{
return(false);
}
}
totalBytesRetired += bufferSize;
bufferPos = 0;
bufferSize = (input == null) ? 0 : input.Read(buffer, 0, buffer.Length);
if (bufferSize < 0)
{
throw new InvalidOperationException("Stream.Read returned a negative count");
}
if (bufferSize == 0)
{
if (mustSucceed)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
else
{
return(false);
}
}
else
{
RecomputeBufferSizeAfterLimit();
int totalBytesRead =
totalBytesRetired + bufferSize + bufferSizeAfterLimit;
if (totalBytesRead > sizeLimit || totalBytesRead < 0)
{
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>
/// Reads and discards <paramref name="size"/> bytes.
/// </summary>
/// <exception cref="InvalidProtocolBufferException">the end of the stream
/// or the current limit was reached</exception>
private void SkipRawBytes(int size)
{
if (size < 0)
{
throw InvalidProtocolBufferException.NegativeSize();
}
if (totalBytesRetired + bufferPos + size > currentLimit)
{
// Read to the end of the stream anyway.
SkipRawBytes(currentLimit - totalBytesRetired - bufferPos);
// Then fail.
throw InvalidProtocolBufferException.TruncatedMessage();
}
if (size <= bufferSize - bufferPos)
{
// We have all the bytes we need already.
bufferPos += size;
}
else
{
// Skipping more bytes than are in the buffer. First skip what we have.
int pos = bufferSize - bufferPos;
// ROK 5/7/2013 Issue #54: should retire all bytes in buffer (bufferSize)
// totalBytesRetired += pos;
totalBytesRetired += bufferSize;
bufferPos = 0;
bufferSize = 0;
// Then skip directly from the InputStream for the rest.
if (pos < size)
{
if (input == null)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
SkipImpl(size - pos);
totalBytesRetired += size - pos;
}
}
}
/// <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);
}
/// <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>
internal int PushLimit(int byteLimit)
{
if (byteLimit < 0)
{
throw InvalidProtocolBufferException.NegativeSize();
}
byteLimit += totalBytesRetired + bufferPos;
int oldLimit = currentLimit;
if (byteLimit > oldLimit)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
currentLimit = byteLimit;
RecomputeBufferSizeAfterLimit();
return(oldLimit);
}
/// <summary>
/// Reads and discards <paramref name="size"/> bytes.
/// </summary>
/// <exception cref="InvalidProtocolBufferException">the end of the stream
/// or the current limit was reached</exception>
public static void SkipRawBytes(ref ReadOnlySpan <byte> buffer, ref ParserInternalState state, int size)
{
if (size < 0)
{
throw InvalidProtocolBufferException.NegativeSize();
}
if (state.totalBytesRetired + state.bufferPos + size > state.currentLimit)
{
// Read to the end of the stream anyway.
SkipRawBytes(ref buffer, ref state, state.currentLimit - state.totalBytesRetired - state.bufferPos);
// Then fail.
throw InvalidProtocolBufferException.TruncatedMessage();
}
if (size <= state.bufferSize - state.bufferPos)
{
// We have all the bytes we need already.
state.bufferPos += size;
}
else
{
// Skipping more bytes than are in the buffer. First skip what we have.
int pos = state.bufferSize - state.bufferPos;
state.bufferPos = state.bufferSize;
// TODO: If our segmented buffer is backed by a Stream that is seekable, we could skip the bytes more efficiently
// by simply updating stream's Position property. This used to be supported in the past, but the support was dropped
// because it would make the segmentedBufferHelper more complex. Support can be reintroduced if needed.
state.segmentedBufferHelper.RefillBuffer(ref buffer, ref state, true);
while (size - pos > state.bufferSize)
{
pos += state.bufferSize;
state.bufferPos = state.bufferSize;
state.segmentedBufferHelper.RefillBuffer(ref buffer, ref state, true);
}
state.bufferPos = size - pos;
}
}
/// <summary>
/// Reads an embedded message field value from the stream.
/// </summary>
public void ReadMessage(IMessage builder)
{
int length = ReadLength();
if (recursionDepth >= recursionLimit)
{
throw InvalidProtocolBufferException.RecursionLimitExceeded();
}
int oldLimit = PushLimit(length);
++recursionDepth;
builder.MergeFrom(this);
CheckReadEndOfStreamTag();
// Check that we've read exactly as much data as expected.
if (!ReachedLimit)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
--recursionDepth;
PopLimit(oldLimit);
}
private void SkipGroup()
{
// 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...
recursionDepth++;
if (recursionDepth >= recursionLimit)
{
throw InvalidProtocolBufferException.RecursionLimitExceeded();
}
uint tag;
do
{
tag = ReadTag();
if (tag == 0)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
// This recursion will allow us to handle nested groups.
SkipLastField();
} while (WireFormat.GetTagWireType(tag) != WireFormat.WireType.EndGroup);
recursionDepth--;
}
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);
}
public void ReadVarint()
{
AssertReadVarint(Bytes(0x00), 0);
AssertReadVarint(Bytes(0x01), 1);
AssertReadVarint(Bytes(0x7f), 127);
// 14882
AssertReadVarint(Bytes(0xa2, 0x74), (0x22 << 0) | (0x74 << 7));
// 2961488830
AssertReadVarint(Bytes(0xbe, 0xf7, 0x92, 0x84, 0x0b),
(0x3e << 0) | (0x77 << 7) | (0x12 << 14) | (0x04 << 21) |
(0x0bL << 28));
// 64-bit
// 7256456126
AssertReadVarint(Bytes(0xbe, 0xf7, 0x92, 0x84, 0x1b),
(0x3e << 0) | (0x77 << 7) | (0x12 << 14) | (0x04 << 21) |
(0x1bL << 28));
// 41256202580718336
AssertReadVarint(Bytes(0x80, 0xe6, 0xeb, 0x9c, 0xc3, 0xc9, 0xa4, 0x49),
(0x00 << 0) | (0x66 << 7) | (0x6b << 14) | (0x1c << 21) |
(0x43L << 28) | (0x49L << 35) | (0x24L << 42) | (0x49L << 49));
// 11964378330978735131
AssertReadVarint(Bytes(0x9b, 0xa8, 0xf9, 0xc2, 0xbb, 0xd6, 0x80, 0x85, 0xa6, 0x01),
(0x1b << 0) | (0x28 << 7) | (0x79 << 14) | (0x42 << 21) |
(0x3bUL << 28) | (0x56UL << 35) | (0x00UL << 42) |
(0x05UL << 49) | (0x26UL << 56) | (0x01UL << 63));
// Failures
AssertReadVarintFailure(
InvalidProtocolBufferException.MalformedVarint(),
Bytes(0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x00));
AssertReadVarintFailure(
InvalidProtocolBufferException.TruncatedMessage(),
Bytes(0x80));
}
/// <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--;
}
/// <summary>
/// Reads a fixed size of bytes from the input.
/// </summary>
/// <exception cref="InvalidProtocolBufferException">
/// the end of the stream or the current limit was reached
/// </exception>
internal byte[] ReadRawBytes(int size)
{
if (size < 0)
{
throw InvalidProtocolBufferException.NegativeSize();
}
if (totalBytesRetired + bufferPos + size > currentLimit)
{
// Read to the end of the stream (up to the current limit) anyway.
SkipRawBytes(currentLimit - totalBytesRetired - bufferPos);
// Then fail.
throw InvalidProtocolBufferException.TruncatedMessage();
}
if (size <= bufferSize - bufferPos)
{
// We have all the bytes we need already.
byte[] bytes = new byte[size];
ByteArray.Copy(buffer, bufferPos, bytes, 0, size);
bufferPos += size;
return(bytes);
}
else if (size < buffer.Length)
{
// Reading more bytes than are in the buffer, but not an excessive number
// of bytes. We can safely allocate the resulting array ahead of time.
// First copy what we have.
byte[] bytes = new byte[size];
int pos = bufferSize - bufferPos;
ByteArray.Copy(buffer, bufferPos, bytes, 0, pos);
bufferPos = bufferSize;
// We want to use RefillBuffer() and then copy from the buffer into our
// byte array rather than reading directly into our byte array because
// the input may be unbuffered.
RefillBuffer(true);
while (size - pos > bufferSize)
{
Buffer.BlockCopy(buffer, 0, bytes, pos, bufferSize);
pos += bufferSize;
bufferPos = bufferSize;
RefillBuffer(true);
}
ByteArray.Copy(buffer, 0, bytes, pos, size - pos);
bufferPos = size - pos;
return(bytes);
}
else
{
// The size is very large. For security reasons, we can't allocate the
// entire byte array yet. The size comes directly from the input, so a
// maliciously-crafted message could provide a bogus very large size in
// order to trick the app into allocating a lot of memory. We avoid this
// by allocating and reading only a small chunk at a time, so that the
// malicious message must actually *be* extremely large to cause
// problems. Meanwhile, we limit the allowed size of a message elsewhere.
// Remember the buffer markers since we'll have to copy the bytes out of
// it later.
int originalBufferPos = bufferPos;
int originalBufferSize = bufferSize;
// Mark the current buffer consumed.
totalBytesRetired += bufferSize;
bufferPos = 0;
bufferSize = 0;
// Read all the rest of the bytes we need.
int sizeLeft = size - (originalBufferSize - originalBufferPos);
List <byte[]> chunks = new List <byte[]>();
while (sizeLeft > 0)
{
byte[] chunk = new byte[Math.Min(sizeLeft, buffer.Length)];
int pos = 0;
while (pos < chunk.Length)
{
int n = (input == null) ? -1 : input.Read(chunk, pos, chunk.Length - pos);
if (n <= 0)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
totalBytesRetired += n;
pos += n;
}
sizeLeft -= chunk.Length;
chunks.Add(chunk);
}
// OK, got everything. Now concatenate it all into one buffer.
byte[] bytes = new byte[size];
// Start by copying the leftover bytes from this.buffer.
int newPos = originalBufferSize - originalBufferPos;
ByteArray.Copy(buffer, originalBufferPos, bytes, 0, newPos);
// And now all the chunks.
foreach (byte[] chunk in chunks)
{
Buffer.BlockCopy(chunk, 0, bytes, newPos, chunk.Length);
newPos += chunk.Length;
}
// Done.
return(bytes);
}
}
public static KeyValuePair <TKey, TValue> ReadMapEntry <TKey, TValue>(ref ParseContext ctx, MapField <TKey, TValue> .Codec codec)
{
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;
TKey key = codec.KeyCodec.DefaultValue;
TValue value = codec.ValueCodec.DefaultValue;
uint tag;
while ((tag = ctx.ReadTag()) != 0)
{
if (tag == codec.KeyCodec.Tag)
{
key = codec.KeyCodec.Read(ref ctx);
}
else if (tag == codec.ValueCodec.Tag)
{
value = codec.ValueCodec.Read(ref ctx);
}
else
{
SkipLastField(ref ctx.buffer, ref ctx.state);
}
}
// Corner case: a map entry with a key but no value, where the value type is a message.
// Read it as if we'd seen input with no data (i.e. create a "default" message).
if (value == null)
{
if (ctx.state.CodedInputStream != null)
{
// the decoded message might not support parsing from ParseContext, so
// we need to allow fallback to the legacy MergeFrom(CodedInputStream) parsing.
value = codec.ValueCodec.Read(new CodedInputStream(ZeroLengthMessageStreamData));
}
else
{
ParseContext.Initialize(new ReadOnlySequence <byte>(ZeroLengthMessageStreamData), out ParseContext zeroLengthCtx);
value = codec.ValueCodec.Read(ref zeroLengthCtx);
}
}
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);
return(new KeyValuePair <TKey, TValue>(key, value));
}
/// <summary>
/// Reads a fixed size of bytes from the input.
/// </summary>
/// <exception cref="InvalidProtocolBufferException">
/// the end of the stream or the current limit was reached
/// </exception>
public static byte[] ReadRawBytes(ref ReadOnlySpan <byte> buffer, ref ParserInternalState state, int size)
{
if (size < 0)
{
throw InvalidProtocolBufferException.NegativeSize();
}
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();
}
if (size <= state.bufferSize - state.bufferPos)
{
// We have all the bytes we need already.
byte[] bytes = new byte[size];
buffer.Slice(state.bufferPos, size).CopyTo(bytes);
state.bufferPos += size;
return(bytes);
}
else if (size < buffer.Length || size < state.segmentedBufferHelper.TotalLength)
{
// Reading more bytes than are in the buffer, but not an excessive number
// of bytes. We can safely allocate the resulting array ahead of time.
// First copy what we have.
byte[] bytes = new byte[size];
var bytesSpan = new Span <byte>(bytes);
int pos = state.bufferSize - state.bufferPos;
buffer.Slice(state.bufferPos, pos).CopyTo(bytesSpan.Slice(0, pos));
state.bufferPos = state.bufferSize;
// We want to use RefillBuffer() and then copy from the buffer into our
// byte array rather than reading directly into our byte array because
// the input may be unbuffered.
state.segmentedBufferHelper.RefillBuffer(ref buffer, ref state, true);
while (size - pos > state.bufferSize)
{
buffer.Slice(0, state.bufferSize)
.CopyTo(bytesSpan.Slice(pos, state.bufferSize));
pos += state.bufferSize;
state.bufferPos = state.bufferSize;
state.segmentedBufferHelper.RefillBuffer(ref buffer, ref state, true);
}
buffer.Slice(0, size - pos)
.CopyTo(bytesSpan.Slice(pos, size - pos));
state.bufferPos = size - pos;
return(bytes);
}
else
{
// The size is very large. For security reasons, we can't allocate the
// entire byte array yet. The size comes directly from the input, so a
// maliciously-crafted message could provide a bogus very large size in
// order to trick the app into allocating a lot of memory. We avoid this
// by allocating and reading only a small chunk at a time, so that the
// malicious message must actually *be* extremely large to cause
// problems. Meanwhile, we limit the allowed size of a message elsewhere.
List <byte[]> chunks = new List <byte[]>();
int pos = state.bufferSize - state.bufferPos;
byte[] firstChunk = new byte[pos];
buffer.Slice(state.bufferPos, pos).CopyTo(firstChunk);
chunks.Add(firstChunk);
state.bufferPos = state.bufferSize;
// Read all the rest of the bytes we need.
int sizeLeft = size - pos;
while (sizeLeft > 0)
{
state.segmentedBufferHelper.RefillBuffer(ref buffer, ref state, true);
byte[] chunk = new byte[Math.Min(sizeLeft, state.bufferSize)];
buffer.Slice(0, chunk.Length)
.CopyTo(chunk);
state.bufferPos += chunk.Length;
sizeLeft -= chunk.Length;
chunks.Add(chunk);
}
// OK, got everything. Now concatenate it all into one buffer.
byte[] bytes = new byte[size];
int newPos = 0;
foreach (byte[] chunk in chunks)
{
Buffer.BlockCopy(chunk, 0, bytes, newPos, chunk.Length);
newPos += chunk.Length;
}
// Done.
return(bytes);
}
}