identity: Add multi-document presentation support.

This new IPresentationSession interface enables an application to do a
multi-document presentation, something which isn't possible with the
existing API. As a practical example of this consider presenting both
your Mobile Driving License and your Vaccination Certificate in a single
transaction.

Bug: 197965513
Test: New CTS tests and new screen in CtsVerifier
Change-Id: I11712dca35df7f1224debf454731bc17ea9bfb37
diff --git a/identity/aidl/default/common/PresentationSession.h b/identity/aidl/default/common/PresentationSession.h
new file mode 100644
index 0000000..76ca67b
--- /dev/null
+++ b/identity/aidl/default/common/PresentationSession.h
@@ -0,0 +1,83 @@
+/*
+ * Copyright 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.
+ */
+
+#ifndef ANDROID_HARDWARE_IDENTITY_PRESENTATIONSESSION_H
+#define ANDROID_HARDWARE_IDENTITY_PRESENTATIONSESSION_H
+
+#include <aidl/android/hardware/identity/BnPresentationSession.h>
+#include <android/hardware/identity/support/IdentityCredentialSupport.h>
+
+#include <vector>
+
+#include <cppbor.h>
+
+#include "IdentityCredentialStore.h"
+#include "SecureHardwareProxy.h"
+
+namespace aidl::android::hardware::identity {
+
+using ::aidl::android::hardware::keymaster::HardwareAuthToken;
+using ::aidl::android::hardware::keymaster::VerificationToken;
+using ::android::sp;
+using ::android::hardware::identity::SecureHardwareSessionProxy;
+using ::std::vector;
+
+class PresentationSession : public BnPresentationSession {
+  public:
+    PresentationSession(sp<SecureHardwareProxyFactory> hwProxyFactory,
+                        sp<SecureHardwareSessionProxy> hwProxy)
+        : hwProxyFactory_(std::move(hwProxyFactory)), hwProxy_(std::move(hwProxy)) {}
+
+    virtual ~PresentationSession();
+
+    // Creates ephemeral key and auth-challenge in TA. Returns a status code from
+    // IIdentityCredentialStore. Must be called right after construction.
+    int initialize();
+
+    uint64_t getSessionId();
+
+    vector<uint8_t> getSessionTranscript();
+    vector<uint8_t> getReaderEphemeralPublicKey();
+
+    // Methods from IPresentationSession follow.
+    ndk::ScopedAStatus getEphemeralKeyPair(vector<uint8_t>* outKeyPair) override;
+    ndk::ScopedAStatus getAuthChallenge(int64_t* outChallenge) override;
+    ndk::ScopedAStatus setReaderEphemeralPublicKey(const vector<uint8_t>& publicKey) override;
+    ndk::ScopedAStatus setSessionTranscript(const vector<uint8_t>& sessionTranscript) override;
+
+    ndk::ScopedAStatus getCredential(const vector<uint8_t>& credentialData,
+                                     shared_ptr<IIdentityCredential>* outCredential) override;
+
+  private:
+    // Set by constructor
+    sp<SecureHardwareProxyFactory> hwProxyFactory_;
+    sp<SecureHardwareSessionProxy> hwProxy_;
+
+    // Set by initialize()
+    uint64_t id_;
+    vector<uint8_t> ephemeralKeyPair_;
+    uint64_t authChallenge_;
+
+    // Set by setReaderEphemeralPublicKey()
+    vector<uint8_t> readerPublicKey_;
+
+    // Set by setSessionTranscript()
+    vector<uint8_t> sessionTranscript_;
+};
+
+}  // namespace aidl::android::hardware::identity
+
+#endif  // ANDROID_HARDWARE_IDENTITY_PRESENTATIONSESSION_H