IRemotelyProvisionedComponent returns DeviceInfo

This alters the AIDL interface and underlying functionality to have the
component return the DeviceInfo CBOR blob that is used as AAD in
verification of a signature over a MAC key. Trying to reconstruct this
from userspace is very likely to lead to pain and subtle errors in the
future as adoption of this HAL increases, and multiple instances of this
HAL may exist on device simultaneously.

Test: atest VtsRemotelyProvisionedComponentTests
Change-Id: I44bd588586652630ed31a87cfda7e9c01cbf0a2f

security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/DeviceInfo.aidl

@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+///////////////////////////////////////////////////////////////////////////////
+// THIS FILE IS IMMUTABLE. DO NOT EDIT IN ANY CASE.                          //
+///////////////////////////////////////////////////////////////////////////////
+
+// This file is a snapshot of an AIDL file. Do not edit it manually. There are
+// two cases:
+// 1). this is a frozen version file - do not edit this in any case.
+// 2). this is a 'current' file. If you make a backwards compatible change to
+//     the interface (from the latest frozen version), the build system will
+//     prompt you to update this file with `m <name>-update-api`.
+//
+// You must not make a backward incompatible change to any AIDL file built
+// with the aidl_interface module type with versions property set. The module
+// type is used to build AIDL files in a way that they can be used across
+// independently updatable components of the system. If a device is shipped
+// with such a backward incompatible change, it has a high risk of breaking
+// later when a module using the interface is updated, e.g., Mainline modules.
+
+package android.hardware.security.keymint;
+/* @hide */
+@VintfStability
+parcelable DeviceInfo {
+  byte[] deviceInfo;
+}

security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/IRemotelyProvisionedComponent.aidl

@@ -35,7 +35,7 @@ package android.hardware.security.keymint;
 @VintfStability
 interface IRemotelyProvisionedComponent {
   byte[] generateEcdsaP256KeyPair(in boolean testMode, out android.hardware.security.keymint.MacedPublicKey macedPublicKey);
-  void generateCertificateRequest(in boolean testMode, in android.hardware.security.keymint.MacedPublicKey[] keysToSign, in byte[] endpointEncryptionCertChain, in byte[] challenge, out byte[] keysToSignMac, out android.hardware.security.keymint.ProtectedData protectedData);
+  byte[] generateCertificateRequest(in boolean testMode, in android.hardware.security.keymint.MacedPublicKey[] keysToSign, in byte[] endpointEncryptionCertChain, in byte[] challenge, out android.hardware.security.keymint.DeviceInfo deviceInfo, out android.hardware.security.keymint.ProtectedData protectedData);
   const int STATUS_FAILED = 1;
   const int STATUS_INVALID_MAC = 2;
   const int STATUS_PRODUCTION_KEY_IN_TEST_REQUEST = 3;

security/keymint/aidl/android/hardware/security/keymint/DeviceInfo.aidl

@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.hardware.security.keymint;
+
+/**
+ * DeviceInfo contains information about the device that's fed in as AAD in the signature of the
+ * device private key over the MAC key used for the bundle of public keys. These values are intended
+ * to be checked by the server to verify that the certificate signing request crafted by
+ * an IRemotelyProvisionedComponent HAL instance is coming from the expected device based
+ * on values initially uploaded during device manufacture in the factory.
+ * @hide
+ */
+@VintfStability
+parcelable DeviceInfo {
+    /**
+     * DeviceInfo is a CBOR Map structure described by the following CDDL.
+     *
+     *     DeviceInfo = {
+     *         ? "brand" : tstr,
+     *         ? "manufacturer" : tstr,
+     *         ? "product" : tstr,
+     *         ? "model" : tstr,
+     *         ? "board" : tstr,
+     *         ? "vb_state" : "green" / "yellow" / "orange",    // Taken from the AVB values
+     *         ? "bootloader_state" : "locked" / "unlocked",    // Taken from the AVB values
+     *         ? "os_version" : tstr,                    // Same as android.os.Build.VERSION.release
+     *         ? "system_patch_level" : uint,                   // YYYYMMDD
+     *         ? "boot_patch_level" : uint,                     // YYYYMMDD
+     *         ? "vendor_patch_level" : uint,                   // YYYYMMDD
+     *     }
+     */
+    byte[] deviceInfo;
+}

security/keymint/aidl/android/hardware/security/keymint/IRemotelyProvisionedComponent.aidl

@@ -16,6 +16,7 @@
 
 package android.hardware.security.keymint;
 
+import android.hardware.security.keymint.DeviceInfo;
 import android.hardware.security.keymint.MacedPublicKey;
 import android.hardware.security.keymint.ProtectedData;
 
@@ -256,7 +257,7 @@ interface IRemotelyProvisionedComponent {
      * @param out ProtectedData contains the encrypted BCC and the ephemeral MAC key used to
      *        authenticate the keysToSign (see keysToSignMac output argument).
      */
-    void generateCertificateRequest(in boolean testMode, in MacedPublicKey[] keysToSign,
-            in byte[] endpointEncryptionCertChain, in byte[] challenge, out byte[] keysToSignMac,
+    byte[] generateCertificateRequest(in boolean testMode, in MacedPublicKey[] keysToSign,
+            in byte[] endpointEncryptionCertChain, in byte[] challenge, out DeviceInfo deviceInfo,
             out ProtectedData protectedData);
 }

security/keymint/aidl/default/RemotelyProvisionedComponent.cpp

@@ -322,8 +322,8 @@ ScopedAStatus RemotelyProvisionedComponent::generateEcdsaP256KeyPair(bool testMo
 
 ScopedAStatus RemotelyProvisionedComponent::generateCertificateRequest(
         bool testMode, const vector<MacedPublicKey>& keysToSign,
-        const bytevec& endpointEncCertChain, const bytevec& challenge, bytevec* keysToSignMac,
-        ProtectedData* protectedData) {
+        const bytevec& endpointEncCertChain, const bytevec& challenge, DeviceInfo* deviceInfo,
+        ProtectedData* protectedData, bytevec* keysToSignMac) {
     auto pubKeysToSign = validateAndExtractPubkeys(testMode, keysToSign,
                                                    testMode ? remote_prov::kTestMacKey : macKey_);
     if (!pubKeysToSign.isOk()) return pubKeysToSign.moveError();
@@ -343,11 +343,12 @@ ScopedAStatus RemotelyProvisionedComponent::generateCertificateRequest(
         bcc = bcc_.clone();
     }
 
+    deviceInfo->deviceInfo = createDeviceInfo();
     auto signedMac = constructCoseSign1(devicePrivKey /* Signing key */,  //
                                         ephemeralMacKey /* Payload */,
                                         cppbor::Array() /* AAD */
                                                 .add(challenge)
-                                                .add(createDeviceInfo())
+                                                .add(deviceInfo->deviceInfo)
                                                 .encode());
     if (!signedMac) return Status(signedMac.moveMessage());
 

security/keymint/aidl/default/RemotelyProvisionedComponent.h

@@ -39,8 +39,8 @@ class RemotelyProvisionedComponent : public BnRemotelyProvisionedComponent {
                                              const std::vector<MacedPublicKey>& keysToSign,
                                              const std::vector<uint8_t>& endpointEncCertChain,
                                              const std::vector<uint8_t>& challenge,
-                                             std::vector<uint8_t>* keysToSignMac,
-                                             ProtectedData* protectedData) override;
+                                             DeviceInfo* deviceInfo, ProtectedData* protectedData,
+                                             std::vector<uint8_t>* keysToSignMac) override;
 
   private:
     // TODO(swillden): Move these into an appropriate Context class.

security/keymint/aidl/vts/functional/VtsRemotelyProvisionedComponentTests.cpp

@@ -227,11 +227,12 @@ class CertificateRequestTest : public VtsRemotelyProvisionedComponentTests {
 TEST_P(CertificateRequestTest, EmptyRequest_testMode) {
     bool testMode = true;
     bytevec keysToSignMac;
+    DeviceInfo deviceInfo;
     ProtectedData protectedData;
     auto challenge = randomBytes(32);
-    auto status = provisionable_->generateCertificateRequest(testMode, {} /* keysToSign */,
-                                                             eekChain_.chain, challenge,
-                                                             &keysToSignMac, &protectedData);
+    auto status = provisionable_->generateCertificateRequest(
+            testMode, {} /* keysToSign */, eekChain_.chain, challenge, &deviceInfo, &protectedData,
+            &keysToSignMac);
     ASSERT_TRUE(status.isOk()) << status.getMessage();
 
     auto [parsedProtectedData, _, protDataErrMsg] = cppbor::parse(protectedData.protectedData);
@@ -297,11 +298,12 @@ TEST_P(CertificateRequestTest, EmptyRequest_testMode) {
 TEST_P(CertificateRequestTest, EmptyRequest_prodMode) {
     bool testMode = false;
     bytevec keysToSignMac;
+    DeviceInfo deviceInfo;
     ProtectedData protectedData;
     auto challenge = randomBytes(32);
-    auto status = provisionable_->generateCertificateRequest(testMode, {} /* keysToSign */,
-                                                             eekChain_.chain, challenge,
-                                                             &keysToSignMac, &protectedData);
+    auto status = provisionable_->generateCertificateRequest(
+            testMode, {} /* keysToSign */, eekChain_.chain, challenge, &deviceInfo, &protectedData,
+            &keysToSignMac);
     ASSERT_FALSE(status.isOk());
     ASSERT_EQ(status.getServiceSpecificError(), BnRemotelyProvisionedComponent::STATUS_INVALID_EEK);
 }
@@ -314,10 +316,12 @@ TEST_P(CertificateRequestTest, NonEmptyRequest_testMode) {
     generateKeys(testMode, 4 /* numKeys */);
 
     bytevec keysToSignMac;
+    DeviceInfo deviceInfo;
     ProtectedData protectedData;
     auto challenge = randomBytes(32);
-    auto status = provisionable_->generateCertificateRequest(
-            testMode, keysToSign_, eekChain_.chain, challenge, &keysToSignMac, &protectedData);
+    auto status = provisionable_->generateCertificateRequest(testMode, keysToSign_, eekChain_.chain,
+                                                             challenge, &deviceInfo, &protectedData,
+                                                             &keysToSignMac);
     ASSERT_TRUE(status.isOk()) << status.getMessage();
 
     auto [parsedProtectedData, _, protDataErrMsg] = cppbor::parse(protectedData.protectedData);
@@ -384,10 +388,12 @@ TEST_P(CertificateRequestTest, NonEmptyRequest_prodMode) {
     generateKeys(testMode, 4 /* numKeys */);
 
     bytevec keysToSignMac;
+    DeviceInfo deviceInfo;
     ProtectedData protectedData;
     auto challenge = randomBytes(32);
-    auto status = provisionable_->generateCertificateRequest(
-            testMode, keysToSign_, eekChain_.chain, challenge, &keysToSignMac, &protectedData);
+    auto status = provisionable_->generateCertificateRequest(testMode, keysToSign_, eekChain_.chain,
+                                                             challenge, &deviceInfo, &protectedData,
+                                                             &keysToSignMac);
     ASSERT_FALSE(status.isOk());
     ASSERT_EQ(status.getServiceSpecificError(), BnRemotelyProvisionedComponent::STATUS_INVALID_EEK);
 }
@@ -400,11 +406,12 @@ TEST_P(CertificateRequestTest, NonEmptyRequest_prodKeyInTestCert) {
     generateKeys(false /* testMode */, 2 /* numKeys */);
 
     bytevec keysToSignMac;
+    DeviceInfo deviceInfo;
     ProtectedData protectedData;
     auto challenge = randomBytes(32);
-    auto status = provisionable_->generateCertificateRequest(true /* testMode */, keysToSign_,
-                                                             eekChain_.chain, challenge,
-                                                             &keysToSignMac, &protectedData);
+    auto status = provisionable_->generateCertificateRequest(
+            true /* testMode */, keysToSign_, eekChain_.chain, challenge, &deviceInfo,
+            &protectedData, &keysToSignMac);
     ASSERT_FALSE(status.isOk());
     ASSERT_EQ(status.getServiceSpecificError(),
               BnRemotelyProvisionedComponent::STATUS_PRODUCTION_KEY_IN_TEST_REQUEST);
@@ -418,10 +425,11 @@ TEST_P(CertificateRequestTest, NonEmptyRequest_testKeyInProdCert) {
     generateKeys(true /* testMode */, 2 /* numKeys */);
 
     bytevec keysToSignMac;
+    DeviceInfo deviceInfo;
     ProtectedData protectedData;
     auto status = provisionable_->generateCertificateRequest(
             false /* testMode */, keysToSign_, eekChain_.chain, randomBytes(32) /* challenge */,
-            &keysToSignMac, &protectedData);
+            &deviceInfo, &protectedData, &keysToSignMac);
     ASSERT_FALSE(status.isOk());
     ASSERT_EQ(status.getServiceSpecificError(),
               BnRemotelyProvisionedComponent::STATUS_TEST_KEY_IN_PRODUCTION_REQUEST);