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Remove some #ifdefs with System.Memory
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@Rob-Hague
Rob-Hague committed Jul 4, 2024
1 parent c552d0d commit 8537eec
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Showing 3 changed files with 4 additions and 173 deletions.
60 changes: 0 additions & 60 deletions src/Renci.SshNet/Common/Extensions.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -235,29 +235,7 @@ public static bool IsEqualTo(this byte[] left, byte[] right)
throw new ArgumentNullException(nameof(right));
}

if (left == right)
{
return true;
}

#if NETSTANDARD2_1_OR_GREATER || NET6_0_OR_GREATER
return left.AsSpan().SequenceEqual(right);
#else
if (left.Length != right.Length)
{
return false;
}

for (var i = 0; i < left.Length; i++)
{
if (left[i] != right[i])
{
return false;
}
}

return true;
#endif
}

/// <summary>
Expand Down Expand Up @@ -297,44 +275,6 @@ public static byte[] TrimLeadingZeros(this byte[] value)
return value;
}

#if NETFRAMEWORK || NETSTANDARD2_0
public static int IndexOf(this byte[] array, byte[] value, int startIndex, int count)
{
if (value.Length > count)
{
return -1;
}

if (value.Length == 0)
{
return 0;
}

for (var i = startIndex; i < startIndex + count - value.Length + 1; i++)
{
if (MatchesAtIndex(i))
{
return i - startIndex;
}
}

return -1;

bool MatchesAtIndex(int i)
{
for (var j = 0; j < value.Length; j++)
{
if (array[i + j] != value[j])
{
return false;
}
}

return true;
}
}
#endif

/// <summary>
/// Pads with leading zeros if needed.
/// </summary>
Expand Down
94 changes: 0 additions & 94 deletions src/Renci.SshNet/Security/Cryptography/Ciphers/AesCipher.CtrImpl.cs
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Original file line number Diff line number Diff line change
@@ -1,8 +1,6 @@
using System;
#if NETSTANDARD2_1_OR_GREATER || NET6_0_OR_GREATER
using System.Buffers.Binary;
using System.Numerics;
#endif
using System.Security.Cryptography;

namespace Renci.SshNet.Security.Cryptography.Ciphers
Expand All @@ -15,13 +13,8 @@ private sealed class CtrImpl : BlockCipher, IDisposable

private readonly ICryptoTransform _encryptor;

#if NETSTANDARD2_1_OR_GREATER || NET6_0_OR_GREATER
private ulong _ivUpper; // The upper 64 bits of the IV
private ulong _ivLower; // The lower 64 bits of the IV
#else
// The same on netfx
private readonly uint[] _packedIV;
#endif

public CtrImpl(
byte[] key,
Expand All @@ -35,12 +28,8 @@ public CtrImpl(
_aes = aes;
_encryptor = aes.CreateEncryptor();

#if NETSTANDARD2_1_OR_GREATER || NET6_0_OR_GREATER
_ivLower = BinaryPrimitives.ReadUInt64BigEndian(iv.AsSpan(8));
_ivUpper = BinaryPrimitives.ReadUInt64BigEndian(iv);
#else
_packedIV = GetPackedIV(iv);
#endif
}

public override byte[] Encrypt(byte[] input, int offset, int length)
Expand Down Expand Up @@ -85,8 +74,6 @@ private byte[] CTREncryptDecrypt(byte[] data, int offset, int length)
return buffer;
}

#if NETSTANDARD2_1_OR_GREATER || NET6_0_OR_GREATER

// creates the Counter array filled with incrementing copies of IV
private void CTRCreateCounterArray(byte[] buffer)
{
Expand Down Expand Up @@ -118,87 +105,6 @@ private static void ArrayXOR(byte[] buffer, byte[] data, int offset, int length)
}
}

#else
// creates the Counter array filled with incrementing copies of IV
private void CTRCreateCounterArray(byte[] buffer)
{
// fill array with IV, increment by 1 for each copy
var words = buffer.Length / 4;
var counter = new uint[words];
for (var i = 0; i < words; i += 4)
{
// write IV to buffer (big endian)
counter[i] = _packedIV[0];
counter[i + 1] = _packedIV[1];
counter[i + 2] = _packedIV[2];
counter[i + 3] = _packedIV[3];

// increment IV (little endian)
if (_packedIV[3] < 0xFF000000u)
{
_packedIV[3] += 0x01000000u;
}
else
{
var j = 3;
do
{
_packedIV[j] = SwapEndianness(SwapEndianness(_packedIV[j]) + 1);
}
while (_packedIV[j] == 0 && --j >= 0);
}
}

// copy uint[] to byte[]
Buffer.BlockCopy(counter, 0, buffer, 0, buffer.Length);
}

// XOR 2 arrays using Uint[] and blockcopy
private static void ArrayXOR(byte[] buffer, byte[] data, int offset, int length)
{
var words = length / 4;
if (length % 4 != 0)
{
words++;
}

// convert original data to words
var datawords = new uint[words];
Buffer.BlockCopy(data, offset, datawords, 0, length);

// convert encrypted IV counter to words
var bufferwords = new uint[words];
Buffer.BlockCopy(buffer, 0, bufferwords, 0, length);

// XOR encrypted Counter with input data
for (var i = 0; i < words; i++)
{
bufferwords[i] = bufferwords[i] ^ datawords[i];
}

// copy uint[] to byte[]
Buffer.BlockCopy(bufferwords, 0, buffer, 0, length);
}

// pack the IV into an array of uint[4]
private static uint[] GetPackedIV(byte[] iv)
{
var packedIV = new uint[4];
packedIV[0] = BitConverter.ToUInt32(iv, 0);
packedIV[1] = BitConverter.ToUInt32(iv, 4);
packedIV[2] = BitConverter.ToUInt32(iv, 8);
packedIV[3] = BitConverter.ToUInt32(iv, 12);

return packedIV;
}

private static uint SwapEndianness(uint x)
{
x = (x >> 16) | (x << 16);
return ((x & 0xFF00FF00) >> 8) | ((x & 0x00FF00FF) << 8);
}
#endif

private void Dispose(bool disposing)
{
if (disposing)
Expand Down
23 changes: 4 additions & 19 deletions src/Renci.SshNet/ShellStream.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -393,11 +393,7 @@ public void Expect(TimeSpan timeout, int lookback, params ExpectAction[] expectA

Debug.Assert(_readHead <= searchHead && searchHead <= _readTail);

#if NETFRAMEWORK || NETSTANDARD2_0
var indexOfMatch = _readBuffer.IndexOf(expectBytes, searchHead, _readTail - searchHead);
#else
var indexOfMatch = _readBuffer.AsSpan(searchHead, _readTail - searchHead).IndexOf(expectBytes);
#endif

if (indexOfMatch >= 0)
{
Expand All @@ -417,7 +413,7 @@ public void Expect(TimeSpan timeout, int lookback, params ExpectAction[] expectA

if (timeout == Timeout.InfiniteTimeSpan)
{
Monitor.Wait(_sync);
_ = Monitor.Wait(_sync);
}
else
{
Expand Down Expand Up @@ -665,24 +661,16 @@ public IAsyncResult BeginExpect(TimeSpan timeout, int lookback, AsyncCallback? c
{
AssertValid();

#if NETFRAMEWORK || NETSTANDARD2_0
var indexOfCr = _readBuffer.IndexOf(_carriageReturnBytes, _readHead, _readTail - _readHead);
#else
var indexOfCr = _readBuffer.AsSpan(_readHead, _readTail - _readHead).IndexOf(_carriageReturnBytes);
#endif

if (indexOfCr >= 0)
{
// We have found \r. We only need to search for \n up to and just after the \r
// (in order to consume \r\n if we can).
#if NETFRAMEWORK || NETSTANDARD2_0
var indexOfLf = indexOfCr + _carriageReturnBytes.Length + _lineFeedBytes.Length <= _readTail - _readHead
? _readBuffer.IndexOf(_lineFeedBytes, _readHead, indexOfCr + _carriageReturnBytes.Length + _lineFeedBytes.Length)
: _readBuffer.IndexOf(_lineFeedBytes, _readHead, indexOfCr);
#else
var indexOfLf = indexOfCr + _carriageReturnBytes.Length + _lineFeedBytes.Length <= _readTail - _readHead
? _readBuffer.AsSpan(_readHead, indexOfCr + _carriageReturnBytes.Length + _lineFeedBytes.Length).IndexOf(_lineFeedBytes)
: _readBuffer.AsSpan(_readHead, indexOfCr).IndexOf(_lineFeedBytes);
#endif

if (indexOfLf >= 0 && indexOfLf < indexOfCr)
{
// If there is \n before the \r, then return up to the \n
Expand Down Expand Up @@ -720,11 +708,8 @@ public IAsyncResult BeginExpect(TimeSpan timeout, int lookback, AsyncCallback? c
else
{
// There is no \r. What about \n?
#if NETFRAMEWORK || NETSTANDARD2_0
var indexOfLf = _readBuffer.IndexOf(_lineFeedBytes, _readHead, _readTail - _readHead);
#else
var indexOfLf = _readBuffer.AsSpan(_readHead, _readTail - _readHead).IndexOf(_lineFeedBytes);
#endif

if (indexOfLf >= 0)
{
var returnText = _encoding.GetString(_readBuffer, _readHead, indexOfLf);
Expand Down

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