SP-1023 Java / Spring Boot Kiosk Demo: Add HMAC verification

src/intTest/java/com/bitpay/demo/AbstractUiIntegrationTest.java

@@ -6,6 +6,8 @@
 package com.bitpay.demo;
 
 import java.util.Map;
+import java.util.Objects;
+import javax.annotation.Nullable;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
 import org.springframework.boot.test.context.SpringBootTest;
@@ -46,11 +48,16 @@ protected ResultActions post(
 
     protected ResultActions post(
         final String url,
-        final String requestBody
+        final String requestBody,
+        @Nullable final Map<String, String> headers
     ) throws Exception {
         final var post = MockMvcRequestBuilders.post(url).content(requestBody)
             .contentType(MediaType.APPLICATION_JSON);
 
+        if (!Objects.isNull(headers)) {
+            headers.forEach((key, value) -> post.header(key, value));
+        }
+
         return getResultActions(post);
     }
 

src/intTest/java/com/bitpay/demo/invoice/infrastructure/ui/updateinvoice/UpdateInvoiceIntegrationTest.java

@@ -7,6 +7,8 @@
 
 import com.bitpay.demo.AbstractUiIntegrationTest;
 import com.bitpay.demo.invoice.domain.Invoice;
+import java.util.Map;
+import javax.annotation.Nullable;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -28,7 +30,11 @@ public void shouldUpdateInvoice() throws Exception {
         final var invoice = createInvoice();
 
         // when
-        final var result = getResultActions(invoice.getUuid().value(), getDataFromFile("updateData.json"));
+        final var result = getResultActions(
+            invoice.getUuid().value(),
+            getDataFromFile("updateData.json"),
+            Map.of("x-signature", "dIFy1UloHI6k5rpdVdl3cADtPF01g/xHKt6rqKuo5Ls=")
+        );
 
         result.andExpect(MockMvcResultMatchers.status().isOk());
         Assertions.assertEquals(
@@ -43,7 +49,11 @@ public void shouldNotUpdateInvoiceWhenInvoiceForUuidDoesNotExists() throws Excep
         final var invoice = createInvoice();
 
         // when
-        final var result = getResultActions("12312412", getDataFromFile("updateData.json"));
+        final var result = getResultActions(
+            "12312412",
+            getDataFromFile("updateData.json"),
+            Map.of("x-signature", "dIFy1UloHI6k5rpdVdl3cADtPF01g/xHKt6rqKuo5Ls=")
+        );
 
         result.andExpect(MockMvcResultMatchers.status().isNotFound());
         Assertions.assertEquals(
@@ -60,7 +70,8 @@ public void shouldNotUpdateInvoiceWhenUpdateDataAreInvalid() throws Exception {
         // when
         final var result = getResultActions(
             invoice.getUuid().value(),
-            getDataFromFile("invalidUpdateData.json")
+            getDataFromFile("invalidUpdateData.json"),
+            Map.of("x-signature", "33SW42rFbxKuGj7s4166nOrWuHHHM1EMxgHmgT5tksU=")
         );
 
         // then
@@ -72,11 +83,31 @@ public void shouldNotUpdateInvoiceWhenUpdateDataAreInvalid() throws Exception {
         );
     }
 
+    @Test
+    public void shouldNotUpdateInvoiceWhenWebhookSignatureVerificationFailed() throws Exception {
+        // given
+        final var invoice = createInvoice();
+
+        // when
+        final var result = getResultActions(
+            "12312412",
+            getDataFromFile("updateData.json"),
+            Map.of("x-signature", "randomsignature")
+        );
+
+        result.andExpect(MockMvcResultMatchers.status().isOk());
+        Assertions.assertEquals(
+            "new",
+            this.invoiceRepository.findById(invoice.getInvoiceId()).getStatus().value()
+        );
+    }
+
     private ResultActions getResultActions(
         final String invoiceUuId,
-        final String requestBody
+        final String requestBody,
+        @Nullable final Map<String, String> headers
     ) throws Exception {
-        return post(URL + invoiceUuId, requestBody);
+        return post(URL + invoiceUuId, requestBody, headers);
     }
 
     private Invoice createInvoice() {

src/main/java/com/bitpay/demo/invoice/infrastructure/features/tasks/updateinvoice/WebhookVerifier.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2023 BitPay.
+ * All rights reserved.
+ */
+
+package com.bitpay.demo.invoice.infrastructure.features.tasks.updateinvoice;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import com.bitpay.demo.DependencyInjection;
+import java.io.UnsupportedEncodingException;
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+import java.util.Base64;
+import javax.crypto.Mac;
+import javax.crypto.spec.SecretKeySpec;
+import lombok.NonNull;
+
+@DependencyInjection
+public class WebhookVerifier {
+    public Boolean verify(
+        @NonNull final String signingKey,
+        @NonNull final String sigHeader,
+        @NonNull final String webhookBody
+    ) throws NoSuchAlgorithmException, InvalidKeyException, UnsupportedEncodingException {
+        String algorithm = "HmacSHA256";
+
+        Mac mac = Mac.getInstance(algorithm);
+        SecretKeySpec secretKeySpec = new SecretKeySpec(signingKey.getBytes(UTF_8), algorithm);
+        mac.init(secretKeySpec);
+
+        byte[] signatureBytes = mac.doFinal(webhookBody.getBytes(UTF_8));
+
+        String calculated = Base64.getEncoder().encodeToString(signatureBytes);
+        Boolean match = sigHeader.equals(calculated);
+
+        return match;
+    }
+}

src/main/java/com/bitpay/demo/invoice/infrastructure/ui/updateinvoice/HttpUpdateInvoice.java

@@ -9,35 +9,81 @@
 import com.bitpay.demo.invoice.application.features.tasks.updateinvoice.ValidationInvoiceUpdateDataFailed;
 import com.bitpay.demo.invoice.domain.InvoiceNotFound;
 import com.bitpay.demo.invoice.domain.InvoiceUuid;
+import com.bitpay.demo.invoice.infrastructure.features.tasks.updateinvoice.WebhookVerifier;
+import com.bitpay.demo.shared.bitpayproperties.BitPayProperties;
+import com.bitpay.demo.shared.logger.LogCode;
+import com.bitpay.demo.shared.logger.Logger;
+import com.google.common.reflect.TypeToken;
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.ToNumberPolicy;
+import java.io.UnsupportedEncodingException;
+import java.lang.reflect.Type;
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
 import java.util.Map;
 import lombok.NonNull;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestHeader;
 import org.springframework.web.bind.annotation.RestController;
 
 @RestController
 public class HttpUpdateInvoice {
     private final UpdateInvoice updateInvoice;
+    private final BitPayProperties bitPayProperties;
+    private final WebhookVerifier webhookVerifier;
+    private final Logger logger;
 
-    public HttpUpdateInvoice(@NonNull final UpdateInvoice updateInvoice) {
+    public HttpUpdateInvoice(
+        @NonNull final UpdateInvoice updateInvoice,
+        @NonNull final BitPayProperties bitPayProperties,
+        @NonNull final WebhookVerifier webhookVerifier,
+        @NonNull final Logger logger
+    ) {
         this.updateInvoice = updateInvoice;
+        this.webhookVerifier = webhookVerifier;
+        this.bitPayProperties = bitPayProperties;
+        this.logger = logger;
     }
 
     @PostMapping("/invoices/{uuid}")
     public void execute(
         @NonNull @PathVariable("uuid") final String invoiceUuid,
-        @NonNull @RequestBody final Map<String, Object> updateData
-    ) throws ReflectiveOperationException, ValidationInvoiceUpdateDataFailed, InvoiceNotFound {
-        var data = (Map<String, Object>) updateData.get("data");
-        var event = (Map<String, Object>) updateData.get("event");
-        if (!event.isEmpty() && event.containsKey("name")) {
-            data.put("eventName", event.get("name"));
-        }
+        @NonNull @RequestBody final String requestBody,
+        @NonNull @RequestHeader("x-signature") final String signature
+    ) throws ReflectiveOperationException,
+        ValidationInvoiceUpdateDataFailed,
+        InvoiceNotFound,
+        NoSuchAlgorithmException,
+        InvalidKeyException,
+        UnsupportedEncodingException {
+        if (this.webhookVerifier.verify(this.bitPayProperties.getToken(), signature, requestBody)) {
+            Type mapType = new TypeToken<Map<String, Object>>(){}.getType();
+            Gson gson = new GsonBuilder()
+                .setObjectToNumberStrategy(ToNumberPolicy.LONG_OR_DOUBLE)
+                .create();
+            Map<String, Object> updateData = gson.fromJson(requestBody, mapType);
+
+            Map<String, Object> data = (Map<String, Object>) updateData.get("data");
+            Map<String, Object> event = (Map<String, Object>) updateData.get("event");
+            if (!event.isEmpty() && event.containsKey("name")) {
+                data.put("eventName", event.get("name"));
+            }
 
-        this.updateInvoice.execute(
-            new InvoiceUuid(invoiceUuid),
-            data
-        );
+            this.updateInvoice.execute(
+                new InvoiceUuid(invoiceUuid),
+                data
+            );
+        } else {
+            this.logger.error(
+                LogCode.IPN_SIGNATURE_VERIFICATION_FAIL,
+                "Webhook signature verification failed",
+                Map.of(
+                    "uuid", invoiceUuid
+                )
+            );
+        }
     }
 }

src/main/java/com/bitpay/demo/shared/logger/LogCode.java

@@ -14,5 +14,6 @@ public enum LogCode {
     INVOICE_UPDATE_FAIL,
     IPN_RECEIVED,
     IPN_VALIDATE_SUCCESS,
-    IPN_VALIDATE_FAIL
+    IPN_VALIDATE_FAIL,
+    IPN_SIGNATURE_VERIFICATION_FAIL
 }