private KrbKdcDHKeyInfo ValidateDHReply(KrbPaPkAsRep pkRep) { var signed = new SignedCms(); signed.Decode(pkRep.DHInfo.DHSignedData.ToArray()); VerifyKdcSignature(signed); return(KrbKdcDHKeyInfo.Decode(signed.ContentInfo.Content)); }
public void ParsePaPkAsRep_SignedDHRep() { KrbPaPkAsRep asrep = KrbPaPkAsRep.Decode(signedPkAsRep); Assert.IsNotNull(asrep); SignedCms signed = new SignedCms(); signed.Decode(asrep.DHInfo.DHSignedData.ToArray()); signed.CheckSignature(verifySignatureOnly: true); }
public void ParsePaPkAsRep_SignedDHRep_KDCDHKeyInfo() { KrbPaPkAsRep asrep = KrbPaPkAsRep.Decode(signedPkAsRep); Assert.IsNotNull(asrep); SignedCms signed = new SignedCms(); signed.Decode(asrep.DHInfo.DHSignedData.ToArray()); signed.CheckSignature(verifySignatureOnly: true); KrbKdcDHKeyInfo keyInfo = KrbKdcDHKeyInfo.Decode(signed.ContentInfo.Content); Assert.IsNotNull(keyInfo); }
private ReadOnlyMemory <byte> DeriveDHKeyAgreement(KrbKdcRep kdcRep, KrbPaPkAsRep pkRep) { var dhKeyInfo = ValidateDHReply(pkRep); var kdcPublicKey = DiffieHellmanKey.ParsePublicKey(dhKeyInfo.SubjectPublicKey, agreement.PublicKey.KeyLength); agreement.ImportPartnerKey(kdcPublicKey); var derivedKey = agreement.GenerateAgreement(); ReadOnlySpan <byte> serverDHNonce = default; if (pkRep.DHInfo.ServerDHNonce.HasValue) { serverDHNonce = pkRep.DHInfo.ServerDHNonce.Value.Span; } var transform = CryptoService.CreateTransform(kdcRep.EncPart.EType); return(PKInitString2Key.String2Key(derivedKey.Span, transform.KeySize, clientDHNonce.Span, serverDHNonce)); }
/// <summary> /// Decrypts the response from the KDC using credential-supplied secrets. /// </summary> /// <typeparam name="T">The return type</typeparam> /// <param name="kdcRep">The response from the KDC to decrypt</param> /// <param name="keyUsage">The KeyUsage salt used to decrypt the response</param> /// <param name="func">The parsing function to process the decrypted response</param> /// <returns>Returns <typeparamref name="T"/> after decryption</returns> public override T DecryptKdcRep <T>(KrbKdcRep kdcRep, KeyUsage keyUsage, Func <ReadOnlyMemory <byte>, T> func) { var paPkRep = kdcRep?.PaData?.FirstOrDefault(a => a.Type == PaDataType.PA_PK_AS_REP); if (paPkRep == null) { throw new KerberosProtocolException("PA-Data doesn't contain PA-PK-AS-REP"); } var pkRep = KrbPaPkAsRep.Decode(paPkRep.Value); if (pkRep.DHInfo != null) { sharedSecret = DeriveDHKeyAgreement(kdcRep, pkRep); } else { throw OnlyKeyAgreementSupportedException(); } return(base.DecryptKdcRep(kdcRep, keyUsage, func)); }
public override async Task <KrbPaData> Validate(KrbKdcReq asReq, PreAuthenticationContext preauth) { var paPk = asReq.PaData.FirstOrDefault(p => p.Type == PaDataType.PA_PK_AS_REQ); if (paPk == null) { return(null); } var pkreq = KrbPaPkAsReq.Decode(paPk.Value); var authPack = await ValidateAuthPack(preauth.Principal, pkreq); ValidateAuthenticator(authPack.PKAuthenticator, asReq.Body); var requestAlg = authPack.ClientPublicValue?.Algorithm?.Algorithm; IKeyAgreement agreement; if (requestAlg?.Value == EllipticCurveDiffieHellman.Value) { agreement = FromEllipticCurveDomainParameters(authPack.ClientPublicValue); } else if (requestAlg?.Value == DiffieHellman.Value) { agreement = await FromDiffieHellmanDomainParametersAsync(authPack.ClientPublicValue); } else { throw OnlyKeyAgreementSupportedException(); } var derivedKey = agreement.GenerateAgreement(); var etype = asReq.Body.EType.First(); var transform = CryptoService.CreateTransform(etype); ReadOnlyMemory <byte> clientDHNonce = authPack.ClientDHNonce.GetValueOrDefault(); ReadOnlyMemory <byte> serverDHNonce = default; if (clientDHNonce.Length > 0) { serverDHNonce = transform.GenerateRandomBytes(agreement.PublicKey.KeyLength); await Service.Principals.CacheKey(agreement.PrivateKey); } var keyInfo = new KrbKdcDHKeyInfo { SubjectPublicKey = agreement.PublicKey.EncodePublicKey() }; if (agreement.PublicKey.CacheExpiry.HasValue) { keyInfo.DHKeyExpiration = agreement.PublicKey.CacheExpiry; keyInfo.Nonce = authPack.PKAuthenticator.Nonce; } var sessionKey = PKInitString2Key.String2Key( derivedKey.Span, transform.KeySize, clientDHNonce.Span, serverDHNonce.Span ); var paPkRep = new KrbPaPkAsRep { DHInfo = new KrbDHReplyInfo { DHSignedData = await SignDHResponseAsync(keyInfo), ServerDHNonce = serverDHNonce } }; preauth.PaData = new[] { new KrbPaData { Type = PaDataType.PA_PK_AS_REP, Value = paPkRep.Encode() } }; preauth.EncryptedPartKey = new KerberosKey(key: sessionKey.ToArray(), etype: etype); return(null); }
public override KrbPaData Validate(KrbKdcReq asReq, PreAuthenticationContext preauth) { if (asReq == null) { throw new ArgumentNullException(nameof(asReq)); } if (preauth == null) { throw new ArgumentNullException(nameof(preauth)); } if (!preauth.PreAuthenticationState.TryGetValue(PaDataType.PA_PK_AS_REQ, out PaDataState paState) || !(paState is PkInitState state)) { return(null); } var authPack = ValidateAuthPack(preauth, state); this.ValidateAuthenticator(authPack.PKAuthenticator, asReq.Body); var requestAlg = authPack.ClientPublicValue?.Algorithm?.Algorithm; IKeyAgreement agreement; if (requestAlg?.Value == EllipticCurveDiffieHellman.Value) { agreement = this.FromEllipticCurveDomainParameters(authPack.ClientPublicValue); } else if (requestAlg?.Value == DiffieHellman.Value) { agreement = this.FromDiffieHellmanDomainParameters(authPack.ClientPublicValue); } else { throw OnlyKeyAgreementSupportedException(); } var derivedKey = agreement.GenerateAgreement(); var preferredEType = GetPreferredEType( asReq.Body.EType, this.Service.Configuration.Defaults.PermittedEncryptionTypes, this.Service.Configuration.Defaults.AllowWeakCrypto ); if (preferredEType is null) { throw new InvalidOperationException("Cannot find a common EType"); } var etype = preferredEType.Value; var transform = CryptoService.CreateTransform(etype); ReadOnlyMemory <byte> clientDHNonce = authPack.ClientDHNonce.GetValueOrDefault(); ReadOnlyMemory <byte> serverDHNonce = default; if (clientDHNonce.Length > 0) { serverDHNonce = transform.GenerateRandomBytes(agreement.PublicKey.KeyLength); this.Service.Principals.CacheKey(agreement.PrivateKey); } var keyInfo = new KrbKdcDHKeyInfo { SubjectPublicKey = agreement.PublicKey.EncodePublicKey() }; if (agreement.PublicKey.CacheExpiry.HasValue) { keyInfo.DHKeyExpiration = agreement.PublicKey.CacheExpiry; keyInfo.Nonce = authPack.PKAuthenticator.Nonce; } var sessionKey = PKInitString2Key.String2Key( derivedKey.Span, transform.KeySize, clientDHNonce.Span, serverDHNonce.Span ); var paPkRep = new KrbPaPkAsRep { DHInfo = new KrbDHReplyInfo { DHSignedData = this.SignDHResponse(keyInfo), ServerDHNonce = serverDHNonce } }; preauth.PaData = new[] { new KrbPaData { Type = PaDataType.PA_PK_AS_REP, Value = paPkRep.Encode() } }; preauth.EncryptedPartKey = new KerberosKey(key: sessionKey.ToArray(), etype: etype); preauth.ClientAuthority = PaDataType.PA_PK_AS_REQ; return(null); }
public void ParsePaPkAsRep() { KrbPaPkAsRep asrep = KrbPaPkAsRep.Decode(signedPkAsRep); Assert.IsNotNull(asrep); }