[ECDsa] Falls back to use BouncyCastle if BCL (Mono) doesn't support

appveyor.yml

@@ -32,7 +32,7 @@ for:
     # some coverage until a proper solution for running the .NET Framework integration tests in CI is found.
     # Running all the tests causes problems which are not worth solving in this rare configuration.
     # See https://github.com/sshnet/SSH.NET/pull/1462 and related links
-    - sh: dotnet test -f net48 -c Debug --no-restore --no-build --results-directory artifacts --logger Appveyor --logger "console;verbosity=normal" --logger "liquid.md;LogFileName=linux_integration_test_net_48_report.md" -p:CollectCoverage=true -p:CoverletOutputFormat=cobertura -p:CoverletOutput=../../artifacts/linux_integration_test_net_48_coverage.xml --filter "Name~Ecdh|Name~Zlib|Name~Gcm" test/Renci.SshNet.IntegrationTests/Renci.SshNet.IntegrationTests.csproj
+    - sh: dotnet test -f net48 -c Debug --no-restore --no-build --results-directory artifacts --logger Appveyor --logger "console;verbosity=normal" --logger "liquid.md;LogFileName=linux_integration_test_net_48_report.md" -p:CollectCoverage=true -p:CoverletOutputFormat=cobertura -p:CoverletOutput=../../artifacts/linux_integration_test_net_48_coverage.xml --filter "Name~Ecdh|Name~ECDsa|Name~Zlib|Name~Gcm" test/Renci.SshNet.IntegrationTests/Renci.SshNet.IntegrationTests.csproj
 
 -
   matrix:

src/Renci.SshNet/Common/SshDataStream.cs

@@ -56,7 +56,7 @@ public bool IsEndOfData
             }
         }
 
-#if NET462 || NETSTANDARD2_0
+#if NETFRAMEWORK || NETSTANDARD2_0
         private int Read(Span<byte> buffer)
         {
             var sharedBuffer = System.Buffers.ArrayPool<byte>.Shared.Rent(buffer.Length);

src/Renci.SshNet/Security/Cryptography/DsaKey.cs

@@ -41,12 +41,7 @@ public class DsaKey : Key, IDisposable
         /// </summary>
         public BigInteger X { get; }
 
-        /// <summary>
-        /// Gets the length of the key in bits.
-        /// </summary>
-        /// <value>
-        /// The bit-length of the key.
-        /// </value>
+        /// <inheritdoc/>
         public override int KeyLength
         {
             get

src/Renci.SshNet/Security/Cryptography/ED25519Key.cs

@@ -40,12 +40,7 @@ public override BigInteger[] Public
             }
         }
 
-        /// <summary>
-        /// Gets the length of the key.
-        /// </summary>
-        /// <value>
-        /// The length of the key.
-        /// </value>
+        /// <inheritdoc/>
         public override int KeyLength
         {
             get

src/Renci.SshNet/Security/Cryptography/EcdsaDigitalSignature.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Globalization;
 
 using Renci.SshNet.Common;
 
@@ -11,7 +10,6 @@ namespace Renci.SshNet.Security.Cryptography
     public class EcdsaDigitalSignature : DigitalSignature, IDisposable
     {
         private readonly EcdsaKey _key;
-        private bool _isDisposed;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="EcdsaDigitalSignature" /> class.
@@ -41,13 +39,8 @@ public override bool Verify(byte[] input, byte[] signature)
             // for 521 sig_size is 132
             var sig_size = _key.KeyLength == 521 ? 132 : _key.KeyLength / 4;
             var ssh_data = new SshDataSignature(signature, sig_size);
-#if NETFRAMEWORK
-            var ecdsa = _key.Ecdsa;
-            ecdsa.HashAlgorithm = _key.HashAlgorithm;
-            return ecdsa.VerifyData(input, ssh_data.Signature);
-#else
-            return _key.Ecdsa.VerifyData(input, ssh_data.Signature, _key.HashAlgorithm);
-#endif
+
+            return _key._impl.Verify(input, ssh_data.Signature);
         }
 
         /// <summary>
@@ -59,13 +52,8 @@ public override bool Verify(byte[] input, byte[] signature)
         /// </returns>
         public override byte[] Sign(byte[] input)
         {
-#if NETFRAMEWORK
-            var ecdsa = _key.Ecdsa;
-            ecdsa.HashAlgorithm = _key.HashAlgorithm;
-            var signed = ecdsa.SignData(input);
-#else
-            var signed = _key.Ecdsa.SignData(input, _key.HashAlgorithm);
-#endif
+            var signed = _key._impl.Sign(input);
+
             var ssh_data = new SshDataSignature(signed.Length) { Signature = signed };
             return ssh_data.GetBytes();
         }
@@ -85,23 +73,6 @@ public void Dispose()
         /// <param name="disposing"><see langword="true"/> to release both managed and unmanaged resources; <see langword="false"/> to release only unmanaged resources.</param>
         protected virtual void Dispose(bool disposing)
         {
-            if (_isDisposed)
-            {
-                return;
-            }
-
-            if (disposing)
-            {
-                _isDisposed = true;
-            }
-        }
-
-        /// <summary>
-        /// Finalizes an instance of the <see cref="EcdsaDigitalSignature"/> class.
-        /// </summary>
-        ~EcdsaDigitalSignature()
-        {
-            Dispose(disposing: false);
         }
 
         private sealed class SshDataSignature : SshData
@@ -155,18 +126,6 @@ protected override void SaveData()
                 WriteBinaryString(_signature_s.ToBigInteger2().ToByteArray().Reverse());
             }
 
-            public new byte[] ReadBinary()
-            {
-                var length = ReadUInt32();
-
-                if (length > int.MaxValue)
-                {
-                    throw new NotSupportedException(string.Format(CultureInfo.CurrentCulture, "Strings longer than {0} is not supported.", int.MaxValue));
-                }
-
-                return ReadBytes((int)length);
-            }
-
             protected override int BufferCapacity
             {
                 get

src/Renci.SshNet/Security/Cryptography/EcdsaKey.BclImpl.cs

@@ -0,0 +1,82 @@
+#if !NET462
+#nullable enable
+using System;
+using System.Security.Cryptography;
+
+using Renci.SshNet.Common;
+
+namespace Renci.SshNet.Security
+{
+    public partial class EcdsaKey : Key, IDisposable
+    {
+        private sealed class BclImpl : Impl
+        {
+            private readonly HashAlgorithmName _hashAlgorithmName;
+
+            public BclImpl(string curve_oid, int cord_size, byte[] qx, byte[] qy, byte[]? privatekey)
+            {
+                var curve = ECCurve.CreateFromValue(curve_oid);
+                var parameter = new ECParameters
+                {
+                    Curve = curve
+                };
+
+                parameter.Q.X = qx;
+                parameter.Q.Y = qy;
+
+                if (privatekey != null)
+                {
+                    parameter.D = privatekey.TrimLeadingZeros().Pad(cord_size);
+                    PrivateKey = parameter.D;
+                }
+
+                Ecdsa = ECDsa.Create(parameter);
+
+                _hashAlgorithmName = KeyLength switch
+                {
+                    <= 256 => HashAlgorithmName.SHA256,
+                    <= 384 => HashAlgorithmName.SHA384,
+                    _ => HashAlgorithmName.SHA512,
+                };
+            }
+
+            public override byte[]? PrivateKey { get; }
+
+            public override ECDsa Ecdsa { get; }
+
+            public override int KeyLength
+            {
+                get
+                {
+                    return Ecdsa.KeySize;
+                }
+            }
+
+            public override byte[] Sign(byte[] input)
+            {
+                return Ecdsa.SignData(input, _hashAlgorithmName);
+            }
+
+            public override bool Verify(byte[] input, byte[] signature)
+            {
+                return Ecdsa.VerifyData(input, signature, _hashAlgorithmName);
+            }
+
+            public override void Export(out byte[] qx, out byte[] qy)
+            {
+                var parameter = Ecdsa.ExportParameters(includePrivateParameters: false);
+                qx = parameter.Q.X!;
+                qy = parameter.Q.Y!;
+            }
+
+            protected override void Dispose(bool disposing)
+            {
+                if (disposing)
+                {
+                    Ecdsa.Dispose();
+                }
+            }
+        }
+    }
+}
+#endif

src/Renci.SshNet/Security/Cryptography/EcdsaKey.BouncyCastleImpl.cs

@@ -0,0 +1,108 @@
+#if !NET
+#nullable enable
+using System.Security.Cryptography;
+
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1.Sec;
+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Crypto.Digests;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Crypto.Signers;
+
+using Renci.SshNet.Common;
+
+namespace Renci.SshNet.Security
+{
+    public partial class EcdsaKey
+    {
+        private sealed class BouncyCastleImpl : Impl
+        {
+            private readonly ECPublicKeyParameters _publicKeyParameters;
+            private readonly ECPrivateKeyParameters? _privateKeyParameters;
+            private readonly DsaDigestSigner _signer;
+
+            public BouncyCastleImpl(string curve_oid, byte[] qx, byte[] qy, byte[]? privatekey)
+            {
+                DerObjectIdentifier oid;
+                IDigest digest;
+                switch (curve_oid)
+                {
+                    case ECDSA_P256_OID_VALUE:
+                        oid = SecObjectIdentifiers.SecP256r1;
+                        digest = new Sha256Digest();
+                        KeyLength = 256;
+                        break;
+                    case ECDSA_P384_OID_VALUE:
+                        oid = SecObjectIdentifiers.SecP384r1;
+                        digest = new Sha384Digest();
+                        KeyLength = 384;
+                        break;
+                    case ECDSA_P521_OID_VALUE:
+                        oid = SecObjectIdentifiers.SecP521r1;
+                        digest = new Sha512Digest();
+                        KeyLength = 521;
+                        break;
+                    default:
+                        throw new SshException("Unexpected OID: " + curve_oid);
+                }
+
+                _signer = new DsaDigestSigner(new ECDsaSigner(), digest, PlainDsaEncoding.Instance);
+
+                var x9ECParameters = SecNamedCurves.GetByOid(oid);
+                var domainParameter = new ECNamedDomainParameters(oid, x9ECParameters);
+
+                if (privatekey != null)
+                {
+                    _privateKeyParameters = new ECPrivateKeyParameters(
+                        new Org.BouncyCastle.Math.BigInteger(1, privatekey),
+                        domainParameter);
+
+                    _publicKeyParameters = new ECPublicKeyParameters(
+                        domainParameter.G.Multiply(_privateKeyParameters.D).Normalize(),
+                        domainParameter);
+                }
+                else
+                {
+                    _publicKeyParameters = new ECPublicKeyParameters(
+                        x9ECParameters.Curve.CreatePoint(
+                            new Org.BouncyCastle.Math.BigInteger(1, qx),
+                            new Org.BouncyCastle.Math.BigInteger(1, qy)),
+                        domainParameter);
+                }
+            }
+
+            public override byte[]? PrivateKey { get; }
+
+            public override ECDsa? Ecdsa { get; }
+
+            public override int KeyLength { get; }
+
+            public override byte[] Sign(byte[] input)
+            {
+                _signer.Init(forSigning: true, _privateKeyParameters);
+                _signer.BlockUpdate(input, 0, input.Length);
+
+                return _signer.GenerateSignature();
+            }
+
+            public override bool Verify(byte[] input, byte[] signature)
+            {
+                _signer.Init(forSigning: false, _publicKeyParameters);
+                _signer.BlockUpdate(input, 0, input.Length);
+
+                return _signer.VerifySignature(signature);
+            }
+
+            public override void Export(out byte[] qx, out byte[] qy)
+            {
+                qx = _publicKeyParameters.Q.XCoord.GetEncoded();
+                qy = _publicKeyParameters.Q.YCoord.GetEncoded();
+            }
+
+            protected override void Dispose(bool disposing)
+            {
+            }
+        }
+    }
+}
+#endif