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Read the underlying buffer in SshDataStream (#1638)

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SshDataStream is a MemoryStream, so we can access the buffer directly.
Also simplify some usage in PrivateKeyFile.
This commit is contained in:
Rob Hague
2025-05-04 12:39:01 +02:00
committed by GitHub
parent 6039e121a8
commit 7c07b10e4a
6 changed files with 129 additions and 159 deletions
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src/Renci.SshNet/Common/Extensions.cs
+24
View File
@@ -19,7 +19,9 @@ namespace Renci.SshNet.Common
/// </summary>
internal static class Extensions
{
#pragma warning disable S4136 // Method overloads should be grouped together
internal static byte[] ToArray(this ServiceName serviceName)
#pragma warning restore S4136 // Method overloads should be grouped together
{
switch (serviceName)
{
@@ -382,6 +384,28 @@ namespace Renci.SshNet.Common
value = default;
return false;
}
internal static ArraySegment<T> Slice<T>(this ArraySegment<T> arraySegment, int index)
{
return new ArraySegment<T>(arraySegment.Array, arraySegment.Offset + index, arraySegment.Count - index);
}
internal static ArraySegment<T> Slice<T>(this ArraySegment<T> arraySegment, int index, int count)
{
return new ArraySegment<T>(arraySegment.Array, arraySegment.Offset + index, count);
}
internal static T[] ToArray<T>(this ArraySegment<T> arraySegment)
{
if (arraySegment.Count == 0)
{
return Array.Empty<T>();
}
var array = new T[arraySegment.Count];
Array.Copy(arraySegment.Array, arraySegment.Offset, array, 0, arraySegment.Count);
return array;
}
#endif
}
}
src/Renci.SshNet/Common/SshDataStream.cs
+56 -55
View File
@@ -1,4 +1,6 @@
using System;
using System.Buffers.Binary;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.Numerics;
@@ -27,7 +29,7 @@ namespace Renci.SshNet.Common
/// <param name="buffer">The array of unsigned bytes from which to create the current stream.</param>
/// <exception cref="ArgumentNullException"><paramref name="buffer"/> is <see langword="null"/>.</exception>
public SshDataStream(byte[] buffer)
: base(buffer)
: base(buffer ?? throw new ArgumentNullException(nameof(buffer)), 0, buffer.Length, writable: true, publiclyVisible: true)
{
}
@@ -39,7 +41,7 @@ namespace Renci.SshNet.Common
/// <param name="count">The number of bytes to load.</param>
/// <exception cref="ArgumentNullException"><paramref name="buffer"/> is <see langword="null"/>.</exception>
public SshDataStream(byte[] buffer, int offset, int count)
: base(buffer, offset, count)
: base(buffer, offset, count, writable: true, publiclyVisible: true)
{
}
@@ -58,19 +60,6 @@ namespace Renci.SshNet.Common
}
#if NETFRAMEWORK || NETSTANDARD2_0
private int Read(Span<byte> buffer)
{
var sharedBuffer = System.Buffers.ArrayPool<byte>.Shared.Rent(buffer.Length);
var numRead = Read(sharedBuffer, 0, buffer.Length);
sharedBuffer.AsSpan(0, numRead).CopyTo(buffer);
System.Buffers.ArrayPool<byte>.Shared.Return(sharedBuffer);
return numRead;
}
private void Write(ReadOnlySpan<byte> buffer)
{
var sharedBuffer = System.Buffers.ArrayPool<byte>.Shared.Rent(buffer.Length);
@@ -90,7 +79,7 @@ namespace Renci.SshNet.Common
public void Write(uint value)
{
Span<byte> bytes = stackalloc byte[4];
System.Buffers.Binary.BinaryPrimitives.WriteUInt32BigEndian(bytes, value);
BinaryPrimitives.WriteUInt32BigEndian(bytes, value);
Write(bytes);
}
@@ -101,7 +90,7 @@ namespace Renci.SshNet.Common
public void Write(ulong value)
{
Span<byte> bytes = stackalloc byte[8];
System.Buffers.Binary.BinaryPrimitives.WriteUInt64BigEndian(bytes, value);
BinaryPrimitives.WriteUInt64BigEndian(bytes, value);
Write(bytes);
}
@@ -137,6 +126,7 @@ namespace Renci.SshNet.Common
/// <exception cref="ArgumentNullException"><paramref name="encoding"/> is <see langword="null"/>.</exception>
public void Write(string s, Encoding encoding)
{
ThrowHelper.ThrowIfNull(s);
ThrowHelper.ThrowIfNull(encoding);
#if NETSTANDARD2_1 || NET
@@ -153,12 +143,21 @@ namespace Renci.SshNet.Common
}
/// <summary>
/// Reads a byte array from the SSH data stream.
/// Reads a length-prefixed byte array from the SSH data stream.
/// </summary>
/// <returns>
/// The byte array read from the SSH data stream.
/// </returns>
public byte[] ReadBinary()
{
return ReadBinarySegment().ToArray();
}
/// <summary>
/// Reads a length-prefixed byte array from the SSH data stream,
/// returned as a view over the underlying buffer.
/// </summary>
internal ArraySegment<byte> ReadBinarySegment()
{
var length = ReadUInt32();
@@ -167,7 +166,23 @@ namespace Renci.SshNet.Common
throw new NotSupportedException(string.Format(CultureInfo.CurrentCulture, "Data longer than {0} is not supported.", int.MaxValue));
}
return ReadBytes((int)length);
var buffer = GetRemainingBuffer().Slice(0, (int)length);
Position += length;
return buffer;
}
/// <summary>
/// Gets a view over the remaining data in the underlying buffer.
/// </summary>
private ArraySegment<byte> GetRemainingBuffer()
{
var success = TryGetBuffer(out var buffer);
Debug.Assert(success, "Expected buffer to be publicly visible");
return buffer.Slice((int)Position);
}
/// <summary>
@@ -205,11 +220,11 @@ namespace Renci.SshNet.Common
/// </returns>
public BigInteger ReadBigInt()
{
var data = ReadBinary();
#if NETSTANDARD2_1 || NET
var data = ReadBinarySegment();
return new BigInteger(data, isBigEndian: true);
#else
var data = ReadBinary();
Array.Reverse(data);
return new BigInteger(data);
#endif
@@ -223,9 +238,9 @@ namespace Renci.SshNet.Common
/// </returns>
public ushort ReadUInt16()
{
Span<byte> bytes = stackalloc byte[2];
ReadBytes(bytes);
return System.Buffers.Binary.BinaryPrimitives.ReadUInt16BigEndian(bytes);
var ret = BinaryPrimitives.ReadUInt16BigEndian(GetRemainingBuffer());
Position += sizeof(ushort);
return ret;
}
/// <summary>
@@ -236,9 +251,9 @@ namespace Renci.SshNet.Common
/// </returns>
public uint ReadUInt32()
{
Span<byte> span = stackalloc byte[4];
ReadBytes(span);
return System.Buffers.Binary.BinaryPrimitives.ReadUInt32BigEndian(span);
var ret = BinaryPrimitives.ReadUInt32BigEndian(GetRemainingBuffer());
Position += sizeof(uint);
return ret;
}
/// <summary>
@@ -249,9 +264,9 @@ namespace Renci.SshNet.Common
/// </returns>
public ulong ReadUInt64()
{
Span<byte> span = stackalloc byte[8];
ReadBytes(span);
return System.Buffers.Binary.BinaryPrimitives.ReadUInt64BigEndian(span);
var ret = BinaryPrimitives.ReadUInt64BigEndian(GetRemainingBuffer());
Position += sizeof(ulong);
return ret;
}
/// <summary>
@@ -265,19 +280,13 @@ namespace Renci.SshNet.Common
{
encoding ??= Encoding.UTF8;
var length = ReadUInt32();
var bytes = ReadBinarySegment();
if (length > int.MaxValue)
{
throw new NotSupportedException(string.Format(CultureInfo.CurrentCulture, "Strings longer than {0} is not supported.", int.MaxValue));
}
var bytes = ReadBytes((int)length);
return encoding.GetString(bytes, 0, bytes.Length);
return encoding.GetString(bytes.Array, bytes.Offset, bytes.Count);
}
/// <summary>
/// Writes the stream contents to a byte array, regardless of the <see cref="MemoryStream.Position"/>.
/// Retrieves the stream contents as a byte array, regardless of the <see cref="MemoryStream.Position"/>.
/// </summary>
/// <returns>
/// This method returns the contents of the <see cref="SshDataStream"/> as a byte array.
@@ -288,9 +297,15 @@ namespace Renci.SshNet.Common
/// </remarks>
public override byte[] ToArray()
{
if (Capacity == Length)
var success = TryGetBuffer(out var buffer);
Debug.Assert(success, "Expected buffer to be publicly visible");
if (buffer.Offset == 0 &&
buffer.Count == buffer.Array.Length &&
buffer.Count == Length)
{
return GetBuffer();
return buffer.Array;
}
return base.ToArray();
@@ -315,19 +330,5 @@ namespace Renci.SshNet.Common
return data;
}
/// <summary>
/// Reads data into the specified <paramref name="buffer" />.
/// </summary>
/// <param name="buffer">The buffer to read into.</param>
/// <exception cref="ArgumentOutOfRangeException"><paramref name="buffer"/> is larger than the total of bytes available.</exception>
private void ReadBytes(Span<byte> buffer)
{
var bytesRead = Read(buffer);
if (bytesRead < buffer.Length)
{
throw new ArgumentOutOfRangeException(nameof(buffer), string.Format(CultureInfo.InvariantCulture, "The requested length ({0}) is greater than the actual number of bytes read ({1}).", buffer.Length, bytesRead));
}
}
}
}
src/Renci.SshNet/PrivateKeyFile.OpenSSH.cs
+19 -20
View File
@@ -32,7 +32,7 @@ namespace Renci.SshNet
/// </summary>
public Key Parse()
{
var keyReader = new SshDataReader(_data);
var keyReader = new SshDataStream(_data);
// check magic header
var authMagic = "openssh-key-v1\0"u8;
@@ -171,7 +171,7 @@ namespace Renci.SshNet
// now parse the data we called the private key, it actually contains the public key again
// so we need to parse through it to get the private key bytes, plus there's some
// validation we need to do.
var privateKeyReader = new SshDataReader(privateKeyBytes);
var privateKeyReader = new SshDataStream(privateKeyBytes);
// check ints should match, they wouldn't match for example if the wrong passphrase was supplied
var checkInt1 = (int)privateKeyReader.ReadUInt32();
@@ -196,33 +196,29 @@ namespace Renci.SshNet
// https://datatracker.ietf.org/doc/html/draft-miller-ssh-agent-11#section-3.2.3
// ENC(A)
_ = privateKeyReader.ReadBignum2();
_ = privateKeyReader.ReadBinarySegment();
// k || ENC(A)
unencryptedPrivateKey = privateKeyReader.ReadBignum2();
unencryptedPrivateKey = privateKeyReader.ReadBinary();
parsedKey = new ED25519Key(unencryptedPrivateKey);
break;
case "ecdsa-sha2-nistp256":
case "ecdsa-sha2-nistp384":
case "ecdsa-sha2-nistp521":
// curve
var len = (int)privateKeyReader.ReadUInt32();
var curve = Encoding.ASCII.GetString(privateKeyReader.ReadBytes(len));
var curve = privateKeyReader.ReadString(Encoding.ASCII);
// public key
publicKey = privateKeyReader.ReadBignum2();
publicKey = privateKeyReader.ReadBinary();
// private key
unencryptedPrivateKey = privateKeyReader.ReadBignum2();
unencryptedPrivateKey = privateKeyReader.ReadBinary();
parsedKey = new EcdsaKey(curve, publicKey, unencryptedPrivateKey.TrimLeadingZeros());
break;
case "ssh-rsa":
var modulus = privateKeyReader.ReadBignum(); // n
var exponent = privateKeyReader.ReadBignum(); // e
var d = privateKeyReader.ReadBignum(); // d
var inverseQ = privateKeyReader.ReadBignum(); // iqmp
var p = privateKeyReader.ReadBignum(); // p
var q = privateKeyReader.ReadBignum(); // q
var modulus = privateKeyReader.ReadBigInt();
var exponent = privateKeyReader.ReadBigInt();
var d = privateKeyReader.ReadBigInt();
var inverseQ = privateKeyReader.ReadBigInt();
var p = privateKeyReader.ReadBigInt();
var q = privateKeyReader.ReadBigInt();
parsedKey = new RsaKey(modulus, exponent, d, p, q, inverseQ);
break;
default:
@@ -233,14 +229,17 @@ namespace Renci.SshNet
// The list of privatekey/comment pairs is padded with the bytes 1, 2, 3, ...
// until the total length is a multiple of the cipher block size.
var padding = privateKeyReader.ReadBytes();
for (var i = 0; i < padding.Length; i++)
int b, i = 0;
while ((b = privateKeyReader.ReadByte()) != -1)
{
if ((int)padding[i] != i + 1)
if (b != i + 1)
{
throw new SshException("Padding of openssh key format contained wrong byte at position: " +
i.ToString(CultureInfo.InvariantCulture));
}
i++;
}
return parsedKey;
src/Renci.SshNet/PrivateKeyFile.PuTTY.cs
+11 -11
View File
@@ -163,34 +163,34 @@ namespace Renci.SshNet
throw new SshException("MAC verification failed for PuTTY key file");
}
var publicKeyReader = new SshDataReader(_publicKey);
var publicKeyReader = new SshDataStream(_publicKey);
var keyType = publicKeyReader.ReadString(Encoding.UTF8);
Debug.Assert(keyType == _algorithmName, $"{nameof(keyType)} is not the same as {nameof(_algorithmName)}");
var privateKeyReader = new SshDataReader(privateKey);
var privateKeyReader = new SshDataStream(privateKey);
Key parsedKey;
switch (keyType)
{
case "ssh-ed25519":
parsedKey = new ED25519Key(privateKeyReader.ReadBignum2());
parsedKey = new ED25519Key(privateKeyReader.ReadBinary());
break;
case "ecdsa-sha2-nistp256":
case "ecdsa-sha2-nistp384":
case "ecdsa-sha2-nistp521":
var curve = publicKeyReader.ReadString(Encoding.ASCII);
var pub = publicKeyReader.ReadBignum2();
var prv = privateKeyReader.ReadBignum2();
var pub = publicKeyReader.ReadBinary();
var prv = privateKeyReader.ReadBinary();
parsedKey = new EcdsaKey(curve, pub, prv);
break;
case "ssh-rsa":
var exponent = publicKeyReader.ReadBignum(); // e
var modulus = publicKeyReader.ReadBignum(); // n
var d = privateKeyReader.ReadBignum(); // d
var p = privateKeyReader.ReadBignum(); // p
var q = privateKeyReader.ReadBignum(); // q
var inverseQ = privateKeyReader.ReadBignum(); // iqmp
var exponent = publicKeyReader.ReadBigInt();
var modulus = publicKeyReader.ReadBigInt();
var d = privateKeyReader.ReadBigInt();
var p = privateKeyReader.ReadBigInt();
var q = privateKeyReader.ReadBigInt();
var inverseQ = privateKeyReader.ReadBigInt();
parsedKey = new RsaKey(modulus, exponent, d, p, q, inverseQ);
break;
default:
src/Renci.SshNet/PrivateKeyFile.SSHCOM.cs
+19 -12
View File
@@ -1,6 +1,7 @@
#nullable enable
using System;
using System.Collections.Generic;
using System.Numerics;
using System.Security.Cryptography;
using System.Text;
@@ -27,7 +28,7 @@ namespace Renci.SshNet
public Key Parse()
{
var reader = new SshDataReader(_data);
var reader = new SshDataStream(_data);
var magicNumber = reader.ReadUInt32();
if (magicNumber != 0x3f6ff9eb)
{
@@ -60,11 +61,7 @@ namespace Renci.SshNet
throw new SshException(string.Format("Cipher method '{0}' is not supported.", ssh2CipherName));
}
/*
* TODO: Create two specific data types to avoid using SshDataReader class.
*/
reader = new SshDataReader(keyData);
reader = new SshDataStream(keyData);
var decryptedLength = reader.ReadUInt32();
@@ -75,16 +72,26 @@ namespace Renci.SshNet
if (keyType.Contains("rsa"))
{
var exponent = reader.ReadBigIntWithBits(); // e
var d = reader.ReadBigIntWithBits(); // d
var modulus = reader.ReadBigIntWithBits(); // n
var inverseQ = reader.ReadBigIntWithBits(); // u
var q = reader.ReadBigIntWithBits(); // p
var p = reader.ReadBigIntWithBits(); // q
var exponent = ReadBigIntWithBits(reader);
var d = ReadBigIntWithBits(reader);
var modulus = ReadBigIntWithBits(reader);
var inverseQ = ReadBigIntWithBits(reader);
var q = ReadBigIntWithBits(reader);
var p = ReadBigIntWithBits(reader);
return new RsaKey(modulus, exponent, d, p, q, inverseQ);
}
throw new NotSupportedException(string.Format("Key type '{0}' is not supported.", keyType));
// Reads next mpint where length is specified in bits.
static BigInteger ReadBigIntWithBits(SshDataStream reader)
{
var numBits = (int)reader.ReadUInt32();
var numBytes = (numBits + 7) / 8;
return reader.ReadBytes(numBytes).ToBigInteger2();
}
}
private static byte[] GetCipherKey(string passphrase, int length)
src/Renci.SshNet/PrivateKeyFile.cs
-61
View File
@@ -6,9 +6,7 @@ using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Numerics;
using System.Security.Cryptography;
using System.Text;
using System.Text.RegularExpressions;
using Renci.SshNet.Common;
@@ -470,65 +468,6 @@ namespace Renci.SshNet
}
}
private sealed class SshDataReader : SshData
{
public SshDataReader(byte[] data)
{
Load(data);
}
public new uint ReadUInt32()
{
return base.ReadUInt32();
}
public new string ReadString(Encoding encoding)
{
return base.ReadString(encoding);
}
public new byte[] ReadBytes(int length)
{
return base.ReadBytes(length);
}
public new byte[] ReadBytes()
{
return base.ReadBytes();
}
/// <summary>
/// Reads next mpint data type from internal buffer where length specified in bits.
/// </summary>
/// <returns>mpint read.</returns>
public BigInteger ReadBigIntWithBits()
{
var length = (int)base.ReadUInt32();
length = (length + 7) / 8;
return base.ReadBytes(length).ToBigInteger2();
}
public BigInteger ReadBignum()
{
return DataStream.ReadBigInt();
}
public byte[] ReadBignum2()
{
return ReadBinary();
}
protected override void LoadData()
{
}
protected override void SaveData()
{
}
}
/// <summary>
/// Represents private key parser.
/// </summary>