Exemplo n.º 1
0
        public void Register(IAppHost appHost)
        {
            if (PrivateKey == null)
            {
                PrivateKey = RsaUtils.CreatePrivateKeyParams();
            }

            appHost.RegisterService(typeof(EncryptedMessagesService), PublicKeyPath);

            PrivateKeyModulusMap = new Dictionary <string, RSAParameters>
            {
                { Convert.ToBase64String(PrivateKey.Value.Modulus), PrivateKey.Value },
            };
            foreach (var fallbackKey in FallbackPrivateKeys)
            {
                PrivateKeyModulusMap[Convert.ToBase64String(fallbackKey.Modulus)] = fallbackKey;
            }

            appHost.RequestConverters.Add((req, requestDto) =>
            {
                var encRequest = requestDto as EncryptedMessage;
                if (encRequest == null)
                {
                    return(null);
                }

                var cryptKey        = new byte[AesUtils.KeySizeBytes];
                var authKey         = new byte[AesUtils.KeySizeBytes];
                var iv              = new byte[AesUtils.BlockSizeBytes];
                const int tagLength = HmacUtils.KeySizeBytes;
                try
                {
                    var privateKey = GetPrivateKey(encRequest.KeyId);
                    if (Equals(privateKey, default(RSAParameters)))
                    {
                        WriteUnencryptedError(req, HttpError.NotFound(ErrorKeyNotFound.Fmt(encRequest.KeyId, PublicKeyPath)), "KeyNotFoundException");
                        return(null);
                    }

                    var authRsaEncCryptKey = Convert.FromBase64String(encRequest.EncryptedSymmetricKey);

                    var rsaEncCryptAuthKeys = new byte[authRsaEncCryptKey.Length - iv.Length - tagLength];

                    Buffer.BlockCopy(authRsaEncCryptKey, 0, iv, 0, iv.Length);
                    Buffer.BlockCopy(authRsaEncCryptKey, iv.Length, rsaEncCryptAuthKeys, 0, rsaEncCryptAuthKeys.Length);

                    var cryptAuthKeys = RsaUtils.Decrypt(rsaEncCryptAuthKeys, privateKey);

                    Buffer.BlockCopy(cryptAuthKeys, 0, cryptKey, 0, cryptKey.Length);
                    Buffer.BlockCopy(cryptAuthKeys, cryptKey.Length, authKey, 0, authKey.Length);

                    //Needs to be after cryptKey,authKey populated
                    if (nonceCache.ContainsKey(iv))
                    {
                        throw HttpError.Forbidden(ErrorNonceSeen);
                    }

                    var now = DateTime.UtcNow;
                    nonceCache.TryAdd(iv, now.Add(MaxRequestAge));

                    if (!HmacUtils.Verify(authRsaEncCryptKey, authKey))
                    {
                        throw new Exception("EncryptedSymmetricKey is Invalid");
                    }

                    var authEncryptedBytes = Convert.FromBase64String(encRequest.EncryptedBody);

                    if (!HmacUtils.Verify(authEncryptedBytes, authKey))
                    {
                        throw new Exception("EncryptedBody is Invalid");
                    }

                    var requestBodyBytes = HmacUtils.DecryptAuthenticated(authEncryptedBytes, cryptKey);
                    var requestBody      = requestBodyBytes.FromUtf8Bytes();

                    if (string.IsNullOrEmpty(requestBody))
                    {
                        throw new ArgumentNullException("EncryptedBody");
                    }

                    var parts    = requestBody.SplitOnFirst(' ');
                    var unixTime = int.Parse(parts[0]);

                    var minRequestDate = now.Subtract(MaxRequestAge);
                    if (unixTime.FromUnixTime() < minRequestDate)
                    {
                        throw HttpError.Forbidden(ErrorRequestTooOld);
                    }

                    DateTime expiredEntry;
                    nonceCache.Where(x => now > x.Value).ToList()
                    .Each(entry => nonceCache.TryRemove(entry.Key, out expiredEntry));

                    parts = parts[1].SplitOnFirst(' ');
                    req.Items[Keywords.InvokeVerb] = parts[0];

                    parts             = parts[1].SplitOnFirst(' ');
                    var operationName = parts[0];
                    var requestJson   = parts[1];

                    var requestType = appHost.Metadata.GetOperationType(operationName);
                    var request     = JsonSerializer.DeserializeFromString(requestJson, requestType);

                    req.Items[RequestItemsCryptKey] = cryptKey;
                    req.Items[RequestItemsAuthKey]  = authKey;
                    req.Items[RequestItemsIv]       = iv;

                    return(request);
                }
                catch (Exception ex)
                {
                    WriteEncryptedError(req, cryptKey, authKey, iv, ex, ErrorInvalidMessage);
                    return(null);
                }
            });

            appHost.ResponseConverters.Add((req, response) =>
            {
                object oCryptKey, oAuthKey, oIv;
                if (!req.Items.TryGetValue(RequestItemsCryptKey, out oCryptKey) ||
                    !req.Items.TryGetValue(RequestItemsAuthKey, out oAuthKey) ||
                    !req.Items.TryGetValue(RequestItemsIv, out oIv))
                {
                    return(null);
                }

                req.Response.ClearCookies();

                var ex = response as Exception;
                if (ex != null)
                {
                    WriteEncryptedError(req, (byte[])oCryptKey, (byte[])oAuthKey, (byte[])oIv, ex);
                    return(null);
                }

                if (response == null)
                {
                    return(new EncryptedMessageResponse());
                }

                var responseBodyBytes  = response.ToJson().ToUtf8Bytes();
                var encryptedBytes     = AesUtils.Encrypt(responseBodyBytes, (byte[])oCryptKey, (byte[])oIv);
                var authEncryptedBytes = HmacUtils.Authenticate(encryptedBytes, (byte[])oAuthKey, (byte[])oIv);
                var encResponse        = new EncryptedMessageResponse
                {
                    EncryptedBody = Convert.ToBase64String(authEncryptedBytes)
                };
                return(encResponse);
            });
        }