diff options
Diffstat (limited to 'Crypto/src/crypto/tls/TlsRsaKeyExchange.cs')
| -rw-r--r-- | Crypto/src/crypto/tls/TlsRsaKeyExchange.cs | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/Crypto/src/crypto/tls/TlsRsaKeyExchange.cs b/Crypto/src/crypto/tls/TlsRsaKeyExchange.cs new file mode 100644 index 000000000..4538a2a81 --- /dev/null +++ b/Crypto/src/crypto/tls/TlsRsaKeyExchange.cs @@ -0,0 +1,165 @@ +using System; +using System.IO; + +using Org.BouncyCastle.Asn1; +using Org.BouncyCastle.Asn1.X509; +using Org.BouncyCastle.Crypto; +using Org.BouncyCastle.Crypto.Encodings; +using Org.BouncyCastle.Crypto.Engines; +using Org.BouncyCastle.Crypto.Parameters; +using Org.BouncyCastle.Security; + +namespace Org.BouncyCastle.Crypto.Tls +{ + /// <summary> + /// TLS 1.0 RSA key exchange. + /// </summary> + internal class TlsRsaKeyExchange + : TlsKeyExchange + { + protected TlsClientContext context; + + protected AsymmetricKeyParameter serverPublicKey = null; + + protected RsaKeyParameters rsaServerPublicKey = null; + + protected byte[] premasterSecret; + + internal TlsRsaKeyExchange(TlsClientContext context) + { + this.context = context; + } + + public virtual void SkipServerCertificate() + { + throw new TlsFatalAlert(AlertDescription.unexpected_message); + } + + public virtual void ProcessServerCertificate(Certificate serverCertificate) + { + X509CertificateStructure x509Cert = serverCertificate.certs[0]; + SubjectPublicKeyInfo keyInfo = x509Cert.SubjectPublicKeyInfo; + + try + { + this.serverPublicKey = PublicKeyFactory.CreateKey(keyInfo); + } +// catch (RuntimeException) + catch (Exception) + { + throw new TlsFatalAlert(AlertDescription.unsupported_certificate); + } + + // Sanity check the PublicKeyFactory + if (this.serverPublicKey.IsPrivate) + { + throw new TlsFatalAlert(AlertDescription.internal_error); + } + + this.rsaServerPublicKey = ValidateRsaPublicKey((RsaKeyParameters)this.serverPublicKey); + + TlsUtilities.ValidateKeyUsage(x509Cert, KeyUsage.KeyEncipherment); + + // TODO + /* + * Perform various checks per RFC2246 7.4.2: "Unless otherwise specified, the + * signing algorithm for the certificate must be the same as the algorithm for the + * certificate key." + */ + } + + public virtual void SkipServerKeyExchange() + { + // OK + } + + public virtual void ProcessServerKeyExchange(Stream input) + { + throw new TlsFatalAlert(AlertDescription.unexpected_message); + } + + public virtual void ValidateCertificateRequest(CertificateRequest certificateRequest) + { + ClientCertificateType[] types = certificateRequest.CertificateTypes; + foreach (ClientCertificateType type in types) + { + switch (type) + { + case ClientCertificateType.rsa_sign: + case ClientCertificateType.dss_sign: + case ClientCertificateType.ecdsa_sign: + break; + default: + throw new TlsFatalAlert(AlertDescription.illegal_parameter); + } + } + } + + public virtual void SkipClientCredentials() + { + // OK + } + + public virtual void ProcessClientCredentials(TlsCredentials clientCredentials) + { + if (!(clientCredentials is TlsSignerCredentials)) + { + throw new TlsFatalAlert(AlertDescription.internal_error); + } + } + + public virtual void GenerateClientKeyExchange(Stream output) + { + this.premasterSecret = TlsRsaUtilities.GenerateEncryptedPreMasterSecret( + context.SecureRandom, this.rsaServerPublicKey, output); + } + + public virtual byte[] GeneratePremasterSecret() + { + byte[] tmp = this.premasterSecret; + this.premasterSecret = null; + return tmp; + } + + // Would be needed to process RSA_EXPORT server key exchange +// protected virtual void ProcessRsaServerKeyExchange(Stream input, ISigner signer) +// { +// Stream sigIn = input; +// if (signer != null) +// { +// sigIn = new SignerStream(input, signer, null); +// } +// +// byte[] modulusBytes = TlsUtilities.ReadOpaque16(sigIn); +// byte[] exponentBytes = TlsUtilities.ReadOpaque16(sigIn); +// +// if (signer != null) +// { +// byte[] sigByte = TlsUtilities.ReadOpaque16(input); +// +// if (!signer.VerifySignature(sigByte)) +// { +// handler.FailWithError(AlertLevel.fatal, AlertDescription.bad_certificate); +// } +// } +// +// BigInteger modulus = new BigInteger(1, modulusBytes); +// BigInteger exponent = new BigInteger(1, exponentBytes); +// +// this.rsaServerPublicKey = ValidateRSAPublicKey(new RsaKeyParameters(false, modulus, exponent)); +// } + + protected virtual RsaKeyParameters ValidateRsaPublicKey(RsaKeyParameters key) + { + // TODO What is the minimum bit length required? +// key.Modulus.BitLength; + + if (!key.Exponent.IsProbablePrime(2)) + { + throw new TlsFatalAlert(AlertDescription.illegal_parameter); + } + + return key; + } + } +} |