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Make keys immutable (#1264)
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This makes it easier to reason about Key instances in e.g.
DigitalSignature implementations, because we know that the
Key is initialised with its data and will not change.

Co-authored-by: Wojciech Nagórski <[email protected]>
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@Rob-Hague @WojciechNagorski
Rob-Hague and WojciechNagorski authored Dec 21, 2023
1 parent e998d87 commit 24838e6
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Showing 15 changed files with 295 additions and 516 deletions.
2 changes: 1 addition & 1 deletion src/Renci.SshNet/Common/SshData.cs
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Expand Up @@ -231,7 +231,7 @@ protected ulong ReadUInt64()
/// <returns>
/// The <see cref="string"/> that was read.
/// </returns>
protected string ReadString(Encoding encoding)
protected string ReadString(Encoding encoding = null)
{
return _stream.ReadString(encoding);
}
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6 changes: 4 additions & 2 deletions src/Renci.SshNet/Common/SshDataStream.cs
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Expand Up @@ -249,12 +249,14 @@ public ulong ReadUInt64()
/// <summary>
/// Reads the next <see cref="string"/> data type from the SSH data stream.
/// </summary>
/// <param name="encoding">The character encoding to use.</param>
/// <param name="encoding">The character encoding to use. Defaults to <see cref="Encoding.UTF8"/>.</param>
/// <returns>
/// The <see cref="string"/> read from the SSH data stream.
/// </returns>
public string ReadString(Encoding encoding)
public string ReadString(Encoding encoding = null)
{
encoding ??= Encoding.UTF8;

var length = ReadUInt32();

if (length > int.MaxValue)
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16 changes: 8 additions & 8 deletions src/Renci.SshNet/ConnectionInfo.cs
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Expand Up @@ -396,16 +396,16 @@ public ConnectionInfo(string host, int port, string username, ProxyTypes proxyTy

HostKeyAlgorithms = new Dictionary<string, Func<byte[], KeyHostAlgorithm>>
{
{ "ssh-ed25519", data => new KeyHostAlgorithm("ssh-ed25519", new ED25519Key(), data) },
{ "ecdsa-sha2-nistp256", data => new KeyHostAlgorithm("ecdsa-sha2-nistp256", new EcdsaKey(), data) },
{ "ecdsa-sha2-nistp384", data => new KeyHostAlgorithm("ecdsa-sha2-nistp384", new EcdsaKey(), data) },
{ "ecdsa-sha2-nistp521", data => new KeyHostAlgorithm("ecdsa-sha2-nistp521", new EcdsaKey(), data) },
{ "ssh-ed25519", data => new KeyHostAlgorithm("ssh-ed25519", new ED25519Key(new SshKeyData(data))) },
{ "ecdsa-sha2-nistp256", data => new KeyHostAlgorithm("ecdsa-sha2-nistp256", new EcdsaKey(new SshKeyData(data))) },
{ "ecdsa-sha2-nistp384", data => new KeyHostAlgorithm("ecdsa-sha2-nistp384", new EcdsaKey(new SshKeyData(data))) },
{ "ecdsa-sha2-nistp521", data => new KeyHostAlgorithm("ecdsa-sha2-nistp521", new EcdsaKey(new SshKeyData(data))) },
#pragma warning disable SA1107 // Code should not contain multiple statements on one line
{ "rsa-sha2-512", data => { var key = new RsaKey(); return new KeyHostAlgorithm("rsa-sha2-512", key, data, new RsaDigitalSignature(key, HashAlgorithmName.SHA512)); } },
{ "rsa-sha2-256", data => { var key = new RsaKey(); return new KeyHostAlgorithm("rsa-sha2-256", key, data, new RsaDigitalSignature(key, HashAlgorithmName.SHA256)); } },
{ "rsa-sha2-512", data => { var key = new RsaKey(new SshKeyData(data)); return new KeyHostAlgorithm("rsa-sha2-512", key, new RsaDigitalSignature(key, HashAlgorithmName.SHA512)); } },
{ "rsa-sha2-256", data => { var key = new RsaKey(new SshKeyData(data)); return new KeyHostAlgorithm("rsa-sha2-256", key, new RsaDigitalSignature(key, HashAlgorithmName.SHA256)); } },
#pragma warning restore SA1107 // Code should not contain multiple statements on one line
{ "ssh-rsa", data => new KeyHostAlgorithm("ssh-rsa", new RsaKey(), data) },
{ "ssh-dss", data => new KeyHostAlgorithm("ssh-dss", new DsaKey(), data) },
{ "ssh-rsa", data => new KeyHostAlgorithm("ssh-rsa", new RsaKey(new SshKeyData(data))) },
{ "ssh-dss", data => new KeyHostAlgorithm("ssh-dss", new DsaKey(new SshKeyData(data))) },
};

CompressionAlgorithms = new Dictionary<string, Type>
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10 changes: 6 additions & 4 deletions src/Renci.SshNet/PrivateKeyFile.cs
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Expand Up @@ -573,12 +573,14 @@ private static Key ParseOpenSshV1Key(byte[] keyFileData, string passPhrase)
switch (keyType)
{
case "ssh-ed25519":
// public key
publicKey = privateKeyReader.ReadBignum2();
// https://datatracker.ietf.org/doc/html/draft-miller-ssh-agent-11#section-3.2.3

// private key
// ENC(A)
_ = privateKeyReader.ReadBignum2();

// k || ENC(A)
unencryptedPrivateKey = privateKeyReader.ReadBignum2();
parsedKey = new ED25519Key(publicKey.Reverse(), unencryptedPrivateKey);
parsedKey = new ED25519Key(unencryptedPrivateKey);
break;
case "ecdsa-sha2-nistp256":
case "ecdsa-sha2-nistp384":
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107 changes: 53 additions & 54 deletions src/Renci.SshNet/Security/Cryptography/DsaKey.cs
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@@ -1,4 +1,5 @@
using System;

using Renci.SshNet.Common;
using Renci.SshNet.Security.Cryptography;

Expand All @@ -15,57 +16,27 @@ public class DsaKey : Key, IDisposable
/// <summary>
/// Gets the P.
/// </summary>
public BigInteger P
{
get
{
return _privateKey[0];
}
}
public BigInteger P { get; }

/// <summary>
/// Gets the Q.
/// </summary>
public BigInteger Q
{
get
{
return _privateKey[1];
}
}
public BigInteger Q { get; }

/// <summary>
/// Gets the G.
/// </summary>
public BigInteger G
{
get
{
return _privateKey[2];
}
}
public BigInteger G { get; }

/// <summary>
/// Gets public key Y.
/// </summary>
public BigInteger Y
{
get
{
return _privateKey[3];
}
}
public BigInteger Y { get; }

/// <summary>
/// Gets private key X.
/// </summary>
public BigInteger X
{
get
{
return _privateKey[4];
}
}
public BigInteger X { get; }

/// <summary>
/// Gets the length of the key.
Expand Down Expand Up @@ -94,46 +65,70 @@ protected internal override DigitalSignature DigitalSignature
}

/// <summary>
/// Gets or sets the public.
/// Gets the DSA public key.
/// </summary>
/// <value>
/// The public.
/// An array whose values are:
/// <list>
/// <item><term>0</term><description><see cref="P"/></description></item>
/// <item><term>1</term><description><see cref="Q"/></description></item>
/// <item><term>2</term><description><see cref="G"/></description></item>
/// <item><term>3</term><description><see cref="Y"/></description></item>
/// </list>
/// </value>
public override BigInteger[] Public
{
get
{
return new[] { P, Q, G, Y };
}
set
{
if (value.Length != 4)
{
throw new InvalidOperationException("Invalid public key.");
}

_privateKey = value;
}
}

/// <summary>
/// Initializes a new instance of the <see cref="DsaKey"/> class.
/// </summary>
public DsaKey()
/// <param name="publicKeyData">The encoded public key data.</param>
public DsaKey(SshKeyData publicKeyData)
{
_privateKey = new BigInteger[5];
if (publicKeyData is null)
{
throw new ArgumentNullException(nameof(publicKeyData));
}

if (publicKeyData.Name != "ssh-dss" || publicKeyData.Keys.Length != 4)
{
throw new ArgumentException($"Invalid DSA public key data. ({publicKeyData.Name}, {publicKeyData.Keys.Length}).", nameof(publicKeyData));
}

P = publicKeyData.Keys[0];
Q = publicKeyData.Keys[1];
G = publicKeyData.Keys[2];
Y = publicKeyData.Keys[3];
}

/// <summary>
/// Initializes a new instance of the <see cref="DsaKey"/> class.
/// </summary>
/// <param name="data">DER encoded private key data.</param>
public DsaKey(byte[] data)
: base(data)
/// <param name="privateKeyData">DER encoded private key data.</param>
public DsaKey(byte[] privateKeyData)
{
if (_privateKey.Length != 5)
if (privateKeyData is null)
{
throw new ArgumentNullException(nameof(privateKeyData));
}

var der = new DerData(privateKeyData);
_ = der.ReadBigInteger(); // skip version

P = der.ReadBigInteger();
Q = der.ReadBigInteger();
G = der.ReadBigInteger();
Y = der.ReadBigInteger();
X = der.ReadBigInteger();

if (!der.IsEndOfData)
{
throw new InvalidOperationException("Invalid private key.");
throw new InvalidOperationException("Invalid private key (expected EOF).");
}
}

Expand All @@ -147,7 +142,11 @@ public DsaKey(byte[] data)
/// <param name="x">The x.</param>
public DsaKey(BigInteger p, BigInteger q, BigInteger g, BigInteger y, BigInteger x)
{
_privateKey = new BigInteger[5] { p, q, g, y, x };
P = p;
Q = q;
G = g;
Y = y;
X = x;
}

/// <summary>
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68 changes: 26 additions & 42 deletions src/Renci.SshNet/Security/Cryptography/ED25519Key.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -11,13 +11,7 @@ namespace Renci.SshNet.Security
/// </summary>
public class ED25519Key : Key, IDisposable
{
#pragma warning disable IDE1006 // Naming Styles
#pragma warning disable SX1309 // Field names should begin with underscore
private readonly byte[] privateKey = new byte[Ed25519.ExpandedPrivateKeySizeInBytes];
#pragma warning restore SX1309 // Field names should begin with underscore
#pragma warning restore IDE1006 // Naming Styles
private ED25519DigitalSignature _digitalSignature;
private byte[] _publicKey = new byte[Ed25519.PublicKeySizeInBytes];
private bool _isDisposed;

/// <summary>
Expand All @@ -32,20 +26,16 @@ public override string ToString()
}

/// <summary>
/// Gets or sets the public.
/// Gets the Ed25519 public key.
/// </summary>
/// <value>
/// The public.
/// An array with <see cref="PublicKey"/> encoded at index 0.
/// </value>
public override BigInteger[] Public
{
get
{
return new BigInteger[] { _publicKey.ToBigInteger2() };
}
set
{
_publicKey = value[0].ToByteArray().Reverse().TrimLeadingZeros().Pad(Ed25519.PublicKeySizeInBytes);
return new BigInteger[] { PublicKey.ToBigInteger2() };
}
}

Expand Down Expand Up @@ -78,52 +68,46 @@ protected internal override DigitalSignature DigitalSignature
/// <summary>
/// Gets the PublicKey Bytes.
/// </summary>
public byte[] PublicKey
{
get
{
return _publicKey;
}
}
public byte[] PublicKey { get; }

/// <summary>
/// Gets the PrivateKey Bytes.
/// </summary>
public byte[] PrivateKey
{
get
{
return privateKey;
}
}
public byte[] PrivateKey { get; }

/// <summary>
/// Initializes a new instance of the <see cref="ED25519Key"/> class.
/// </summary>
public ED25519Key()
/// <param name="publicKeyData">The encoded public key data.</param>
public ED25519Key(SshKeyData publicKeyData)
{
}
if (publicKeyData is null)
{
throw new ArgumentNullException(nameof(publicKeyData));
}

/// <summary>
/// Initializes a new instance of the <see cref="ED25519Key"/> class.
/// </summary>
/// <param name="pk">pk data.</param>
public ED25519Key(byte[] pk)
{
_publicKey = pk.TrimLeadingZeros().Pad(Ed25519.PublicKeySizeInBytes);
if (publicKeyData.Name != "ssh-ed25519" || publicKeyData.Keys.Length != 1)
{
throw new ArgumentException($"Invalid Ed25519 public key data ({publicKeyData.Name}, {publicKeyData.Keys.Length}).", nameof(publicKeyData));
}

PublicKey = publicKeyData.Keys[0].ToByteArray().Reverse().TrimLeadingZeros().Pad(Ed25519.PublicKeySizeInBytes);
PrivateKey = new byte[Ed25519.ExpandedPrivateKeySizeInBytes];
}

/// <summary>
/// Initializes a new instance of the <see cref="ED25519Key"/> class.
/// </summary>
/// <param name="pk">pk data.</param>
/// <param name="sk">sk data.</param>
public ED25519Key(byte[] pk, byte[] sk)
/// <param name="privateKeyData">
/// The private key data <c>k || ENC(A)</c> as described in RFC 8032.
/// </param>
public ED25519Key(byte[] privateKeyData)
{
_publicKey = pk.TrimLeadingZeros().Pad(Ed25519.PublicKeySizeInBytes);
var seed = new byte[Ed25519.PrivateKeySeedSizeInBytes];
Buffer.BlockCopy(sk, 0, seed, 0, seed.Length);
Ed25519.KeyPairFromSeed(out _publicKey, out privateKey, seed);
Buffer.BlockCopy(privateKeyData, 0, seed, 0, seed.Length);
Ed25519.KeyPairFromSeed(out var publicKey, out var privateKey, seed);
PublicKey = publicKey;
PrivateKey = privateKey;
}

/// <summary>
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