Add support for RKP to credstore

Call out to keystore and request remotely provisioned attestation keys.
This reduces our dependence on factory-provisioned attestation keys.

Test: CtsIdentityTestCases
Bug: 194696876
Change-Id: Ief07750ef6b2a465060c64207063568b9a51af68
diff --git a/identity/CredentialStore.cpp b/identity/CredentialStore.cpp
index 61a9125..c5c429b 100644
--- a/identity/CredentialStore.cpp
+++ b/identity/CredentialStore.cpp
@@ -17,10 +17,15 @@
 #define LOG_TAG "credstore"
 
 #include <algorithm>
+#include <optional>
 
 #include <android-base/logging.h>
-
+#include <android/hardware/security/keymint/IRemotelyProvisionedComponent.h>
+#include <android/hardware/security/keymint/RpcHardwareInfo.h>
+#include <android/security/remoteprovisioning/IRemotelyProvisionedKeyPool.h>
+#include <android/security/remoteprovisioning/RemotelyProvisionedKey.h>
 #include <binder/IPCThreadState.h>
+#include <binder/IServiceManager.h>
 
 #include "Credential.h"
 #include "CredentialData.h"
@@ -32,6 +37,46 @@
 namespace android {
 namespace security {
 namespace identity {
+namespace {
+
+using ::android::hardware::security::keymint::IRemotelyProvisionedComponent;
+using ::android::hardware::security::keymint::RpcHardwareInfo;
+using ::android::security::remoteprovisioning::IRemotelyProvisionedKeyPool;
+using ::android::security::remoteprovisioning::RemotelyProvisionedKey;
+
+std::optional<std::string>
+getRemotelyProvisionedComponentId(const sp<IIdentityCredentialStore>& hal) {
+    auto init = [](const sp<IIdentityCredentialStore>& hal) -> std::optional<std::string> {
+        sp<IRemotelyProvisionedComponent> remotelyProvisionedComponent;
+        Status status = hal->getRemotelyProvisionedComponent(&remotelyProvisionedComponent);
+        if (!status.isOk()) {
+            LOG(ERROR) << "Error getting remotely provisioned component: " << status;
+            return std::nullopt;
+        }
+
+        RpcHardwareInfo rpcHwInfo;
+        status = remotelyProvisionedComponent->getHardwareInfo(&rpcHwInfo);
+        if (!status.isOk()) {
+            LOG(ERROR) << "Error getting remotely provisioned component hardware info: " << status;
+            return std::nullopt;
+        }
+
+        if (!rpcHwInfo.uniqueId) {
+            LOG(ERROR) << "Remotely provisioned component is missing a unique id, which is "
+                       << "required for credential key remotely provisioned attestation keys. "
+                       << "This is a bug in the vendor implementation.";
+            return std::nullopt;
+        }
+
+        // This id is required to later fetch remotely provisioned attestation keys.
+        return *rpcHwInfo.uniqueId;
+    };
+
+    static std::optional<std::string> id = init(hal);
+    return id;
+}
+
+}  // namespace
 
 CredentialStore::CredentialStore(const std::string& dataPath, sp<IIdentityCredentialStore> hal)
     : dataPath_(dataPath), hal_(hal) {}
@@ -44,6 +89,16 @@
     }
     halApiVersion_ = hal_->getInterfaceVersion();
 
+    if (hwInfo_.isRemoteKeyProvisioningSupported) {
+        keyPool_ = android::waitForService<IRemotelyProvisionedKeyPool>(
+            IRemotelyProvisionedKeyPool::descriptor);
+        if (keyPool_.get() == nullptr) {
+            LOG(ERROR) << "Error getting IRemotelyProvisionedKeyPool HAL with service name '"
+                       << IRemotelyProvisionedKeyPool::descriptor << "'";
+            return false;
+        }
+    }
+
     LOG(INFO) << "Connected to Identity Credential HAL with API version " << halApiVersion_
               << " and name '" << hwInfo_.credentialStoreName << "' authored by '"
               << hwInfo_.credentialStoreAuthorName << "' with chunk size " << hwInfo_.dataChunkSize
@@ -90,6 +145,13 @@
         return halStatusToGenericError(status);
     }
 
+    if (hwInfo_.isRemoteKeyProvisioningSupported) {
+        status = setRemotelyProvisionedAttestationKey(halWritableCredential.get());
+        if (!status.isOk()) {
+            return halStatusToGenericError(status);
+        }
+    }
+
     sp<IWritableCredential> writableCredential = new WritableCredential(
         dataPath_, credentialName, docType, false, hwInfo_, halWritableCredential);
     *_aidl_return = writableCredential;
@@ -145,6 +207,33 @@
     return Status::ok();
 }
 
+Status CredentialStore::setRemotelyProvisionedAttestationKey(
+    IWritableIdentityCredential* halWritableCredential) {
+    std::optional<std::string> rpcId = getRemotelyProvisionedComponentId(hal_);
+    if (!rpcId) {
+        return Status::fromServiceSpecificError(ERROR_GENERIC,
+                                                "Error getting remotely provisioned component id");
+    }
+
+    uid_t callingUid = android::IPCThreadState::self()->getCallingUid();
+    RemotelyProvisionedKey key;
+    Status status = keyPool_->getAttestationKey(callingUid, *rpcId, &key);
+    if (!status.isOk()) {
+        LOG(WARNING) << "Unable to fetch remotely provisioned attestation key, falling back "
+                     << "to the factory-provisioned attestation key.";
+        return Status::ok();
+    }
+
+    status = halWritableCredential->setRemotelyProvisionedAttestationKey(key.keyBlob,
+                                                                         key.encodedCertChain);
+    if (!status.isOk()) {
+        LOG(ERROR) << "Error setting remotely provisioned attestation key on credential";
+        return status;
+    }
+
+    return Status::ok();
+}
+
 }  // namespace identity
 }  // namespace security
 }  // namespace android