Add encryption in incidentd.

+ Sections which require encryption will be encryted on disk.

+ When the sections are requested by clients (e.g., permission controller, report assignee),
  incidentd will decrypte the data.

+ For efficiency, encryption is done ONLY for sections that require encryption.

+ Use Keystore API for key management.

Bug: 131084614
Test: incidentd_test
Change-Id: I84d6b86807ba5bbde1051e847b2df6e79e6b5be5

10 files changed, 466 insertions, 23 deletions

diff --git a/cmds/incidentd/src/Privacy.cpp b/cmds/incidentd/src/Privacy.cpp
index 386303b038e7..91f0dd3a5c35 100644
--- a/cmds/incidentd/src/Privacy.cpp
+++ b/cmds/incidentd/src/Privacy.cpp
@@ -37,6 +37,8 @@ const Privacy* lookup(const Privacy* p, uint32_t fieldId) {
     return NULL;
 }
 
+bool sectionEncryption(int section_id) { return section_id == 3025 /*restricted image section*/; }
+
 static bool isAllowed(const uint8_t policy, const uint8_t check) {
     switch (check) {
         case PRIVACY_POLICY_LOCAL:
diff --git a/cmds/incidentd/src/Privacy.h b/cmds/incidentd/src/Privacy.h
index fc8caae7fc60..b599c1c4e344 100644
--- a/cmds/incidentd/src/Privacy.h
+++ b/cmds/incidentd/src/Privacy.h
@@ -87,6 +87,9 @@ private:
     uint8_t mPolicy;
 };
 
+// TODO: Add privacy flag in incident.proto and auto generate it inside Privacy.
+bool sectionEncryption(int section_id);
+
 }  // namespace incidentd
 }  // namespace os
 }  // namespace android
diff --git a/cmds/incidentd/src/PrivacyFilter.cpp b/cmds/incidentd/src/PrivacyFilter.cpp
index 7126322575d5..e8fa4f4ee58e 100644
--- a/cmds/incidentd/src/PrivacyFilter.cpp
+++ b/cmds/incidentd/src/PrivacyFilter.cpp
@@ -16,15 +16,18 @@
 #define DEBUG false
 #include "Log.h"
 
-#include "incidentd_util.h"
 #include "PrivacyFilter.h"
-#include "proto_util.h"
 
 #include <android-base/file.h>
-#include <android/util/protobuf.h>
 #include <android/util/ProtoFileReader.h>
+#include <android/util/protobuf.h>
 #include <log/log.h>
 
+#include "cipher/IncidentKeyStore.h"
+#include "cipher/ProtoEncryption.h"
+#include "incidentd_util.h"
+#include "proto_util.h"
+
 namespace android {
 namespace os {
 namespace incidentd {
@@ -141,6 +144,8 @@ public:
      */
     status_t writeData(int fd);
 
+    sp<ProtoReader> getData() { return mData; }
+
 private:
     /**
      * The global set of field --> required privacy level mapping.
@@ -247,8 +252,47 @@ void PrivacyFilter::addFd(const sp<FilterFd>& output) {
     mOutputs.push_back(output);
 }
 
-status_t PrivacyFilter::writeData(const FdBuffer& buffer, uint8_t bufferLevel,
-        size_t* maxSize) {
+static void write_section_to_file(int sectionId, FieldStripper& fieldStripper, sp<FilterFd> output,
+                                  bool encryptIfNeeded) {
+    status_t err;
+
+    if (sectionEncryption(sectionId) && encryptIfNeeded) {
+        ProtoEncryptor encryptor(fieldStripper.getData());
+        size_t encryptedSize = encryptor.encrypt();
+
+        if (encryptedSize <= 0) {
+            output->onWriteError(BAD_VALUE);
+            return;
+        }
+        err = write_section_header(output->getFd(), sectionId, encryptedSize);
+        VLOG("Encrypted: write section header size %lu", (unsigned long)encryptedSize);
+
+        encryptor.flush(output->getFd());
+
+        if (err != NO_ERROR) {
+            output->onWriteError(err);
+            return;
+        }
+    } else {
+        err = write_section_header(output->getFd(), sectionId, fieldStripper.dataSize());
+        VLOG("No encryption: write section header size %lu",
+             (unsigned long)fieldStripper.dataSize());
+
+        if (err != NO_ERROR) {
+            output->onWriteError(err);
+            return;
+        }
+
+        err = fieldStripper.writeData(output->getFd());
+        if (err != NO_ERROR) {
+            output->onWriteError(err);
+            return;
+        }
+    }
+}
+
+status_t PrivacyFilter::writeData(const FdBuffer& buffer, uint8_t bufferLevel, size_t* maxSize,
+                                  bool encryptIfNeeded) {
     status_t err;
 
     if (maxSize != NULL) {
@@ -258,9 +302,9 @@ status_t PrivacyFilter::writeData(const FdBuffer& buffer, uint8_t bufferLevel,
     // Order the writes by privacy filter, with increasing levels of filtration,k
     // so we can do the filter once, and then write many times.
     sort(mOutputs.begin(), mOutputs.end(),
-        [](const sp<FilterFd>& a, const sp<FilterFd>& b) -> bool { 
-            return a->getPrivacyPolicy() < b->getPrivacyPolicy();
-        });
+         [](const sp<FilterFd>& a, const sp<FilterFd>& b) -> bool {
+             return a->getPrivacyPolicy() < b->getPrivacyPolicy();
+         });
 
     uint8_t privacyPolicy = PRIVACY_POLICY_LOCAL; // a.k.a. no filtering
     FieldStripper fieldStripper(mRestrictions, buffer.data()->read(), bufferLevel);
@@ -279,17 +323,7 @@ status_t PrivacyFilter::writeData(const FdBuffer& buffer, uint8_t bufferLevel,
         // Write the resultant buffer to the fd, along with the header.
         ssize_t dataSize = fieldStripper.dataSize();
         if (dataSize > 0) {
-            err = write_section_header(output->getFd(), mSectionId, dataSize);
-            if (err != NO_ERROR) {
-                output->onWriteError(err);
-                continue;
-            }
-
-            err = fieldStripper.writeData(output->getFd());
-            if (err != NO_ERROR) {
-                output->onWriteError(err);
-                continue;
-            }
+            write_section_to_file(mSectionId, fieldStripper, output, encryptIfNeeded);
         }
 
         if (maxSize != NULL) {
@@ -334,14 +368,25 @@ status_t filter_and_write_report(int to, int from, uint8_t bufferLevel,
         uint32_t fieldId = read_field_id(fieldTag);
         uint8_t wireType = read_wire_type(fieldTag);
         if (wireType == WIRE_TYPE_LENGTH_DELIMITED && args.containsSection(fieldId)) {
+            VLOG("Read section %d", fieldId);
             // We need this field, but we need to strip it to the level provided in args.
             PrivacyFilter filter(fieldId, get_privacy_of_section(fieldId));
             filter.addFd(new ReadbackFilterFd(args.getPrivacyPolicy(), to));
 
             // Read this section from the reader into an FdBuffer
             size_t sectionSize = reader->readRawVarint();
+
             FdBuffer sectionData;
-            err = sectionData.write(reader, sectionSize);
+
+            // Write data to FdBuffer, if the section was encrypted, decrypt first.
+            if (sectionEncryption(fieldId)) {
+                VLOG("sectionSize %lu", (unsigned long)sectionSize);
+                ProtoDecryptor decryptor(reader, sectionSize);
+                err = decryptor.decryptAndFlush(&sectionData);
+            } else {
+                err = sectionData.write(reader, sectionSize);
+            }
+
             if (err != NO_ERROR) {
                 ALOGW("filter_and_write_report FdBuffer.write failed (this shouldn't happen): %s",
                         strerror(-err));
@@ -349,7 +394,8 @@ status_t filter_and_write_report(int to, int from, uint8_t bufferLevel,
             }
 
             // Do the filter and write.
-            err = filter.writeData(sectionData, bufferLevel, nullptr);
+            err = filter.writeData(sectionData, bufferLevel, nullptr,
+                                   false /* do not encrypt again*/);
             if (err != NO_ERROR) {
                 ALOGW("filter_and_write_report filter.writeData had an error: %s", strerror(-err));
                 return err;
@@ -358,6 +404,7 @@ status_t filter_and_write_report(int to, int from, uint8_t bufferLevel,
             // We don't need this field.  Incident does not have any direct children
             // other than sections.  So just skip them.
             write_field_or_skip(NULL, reader, fieldTag, true);
+            VLOG("Skip this.... section %d", fieldId);
         }
     }
 
diff --git a/cmds/incidentd/src/PrivacyFilter.h b/cmds/incidentd/src/PrivacyFilter.h
index 76b28498a0ac..d426db966a9a 100644
--- a/cmds/incidentd/src/PrivacyFilter.h
+++ b/cmds/incidentd/src/PrivacyFilter.h
@@ -82,8 +82,14 @@ public:
      * was written (i.e. after filtering).
      *
      * The buffer is assumed to have already been filtered to bufferLevel.
+     *
+     * This function can be called when persisting data to disk or when sending
+     * data to client. In the former case, we need to encrypt the data when that
+     * section requires encryption. In the latter case, we shouldn't send the
+     * unencrypted data to client.
      */
-    status_t writeData(const FdBuffer& buffer, uint8_t bufferLevel, size_t* maxSize);
+    status_t writeData(const FdBuffer& buffer, uint8_t bufferLevel, size_t* maxSize,
+                       bool encryptIfNeeded);
 
 private:
     int mSectionId;
diff --git a/cmds/incidentd/src/Reporter.cpp b/cmds/incidentd/src/Reporter.cpp
index 218c1b27fdcc..322b97293a26 100644
--- a/cmds/incidentd/src/Reporter.cpp
+++ b/cmds/incidentd/src/Reporter.cpp
@@ -447,7 +447,8 @@ status_t ReportWriter::writeSection(const FdBuffer& buffer) {
         }
     });
 
-    return filter.writeData(buffer, PRIVACY_POLICY_LOCAL, &mMaxSectionDataFilteredSize);
+    return filter.writeData(buffer, PRIVACY_POLICY_LOCAL, &mMaxSectionDataFilteredSize,
+                            true /*encrypt if needed*/);
 }
 
 
diff --git a/cmds/incidentd/src/cipher/IncidentKeyStore.cpp b/cmds/incidentd/src/cipher/IncidentKeyStore.cpp
new file mode 100644
index 000000000000..ae0a92094d0b
--- /dev/null
+++ b/cmds/incidentd/src/cipher/IncidentKeyStore.cpp
@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2019 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.
+ */
+
+#include "Log.h"
+
+#include "IncidentKeyStore.h"
+
+#include <sys/stat.h>
+
+static constexpr size_t AES_KEY_BYTES = 32;
+static constexpr size_t GCM_MAC_BYTES = 16;
+constexpr char kKeyname[] = "IncidentKey";
+
+namespace android {
+namespace os {
+namespace incidentd {
+
+using namespace keystore;
+using std::string;
+
+IncidentKeyStore& IncidentKeyStore::getInstance() {
+    static IncidentKeyStore sInstance(new keystore::KeystoreClientImpl);
+    return sInstance;
+}
+
+bool IncidentKeyStore::encrypt(const string& data, int32_t flags, string* output) {
+    std::lock_guard<std::mutex> lock(mMutex);
+    if (data.empty()) {
+        ALOGW("IncidentKeyStore: Encrypt empty data?!");
+        return false;
+    }
+    if (!mClient->doesKeyExist(kKeyname)) {
+        auto gen_result = generateKeyLocked(kKeyname, 0);
+        if (!gen_result.isOk()) {
+            ALOGE("IncidentKeyStore: Key generate failed.");
+            return false;
+        }
+    }
+    if (!mClient->encryptWithAuthentication(kKeyname, data, flags, output)) {
+        ALOGE("IncidentKeyStore: Encryption failed.");
+        return false;
+    }
+    return true;
+}
+
+bool IncidentKeyStore::decrypt(const std::string& input, string* output) {
+    std::lock_guard<std::mutex> lock(mMutex);
+    if (input.empty()) {
+        ALOGE("IncidentKeyStore: Decrypt empty input?");
+        return false;
+    }
+    if (!mClient->decryptWithAuthentication(kKeyname, input, output)) {
+        ALOGE("IncidentKeyStore: Decryption failed.");
+        return false;
+    }
+    return true;
+}
+
+KeyStoreNativeReturnCode IncidentKeyStore::generateKeyLocked(const std::string& name,
+                                                             int32_t flags) {
+    auto paramBuilder = AuthorizationSetBuilder()
+                                .AesEncryptionKey(AES_KEY_BYTES * 8)
+                                .GcmModeMinMacLen(GCM_MAC_BYTES * 8)
+                                .Authorization(TAG_NO_AUTH_REQUIRED);
+
+    AuthorizationSet hardware_enforced_characteristics;
+    AuthorizationSet software_enforced_characteristics;
+    return mClient->generateKey(name, paramBuilder, flags, &hardware_enforced_characteristics,
+                                &software_enforced_characteristics);
+}
+
+}  // namespace incidentd
+}  // namespace os
+}  // namespace android
diff --git a/cmds/incidentd/src/cipher/IncidentKeyStore.h b/cmds/incidentd/src/cipher/IncidentKeyStore.h
new file mode 100644
index 000000000000..27611cd7faad
--- /dev/null
+++ b/cmds/incidentd/src/cipher/IncidentKeyStore.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2019 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.
+ */
+#pragma once
+
+#include <keystore/keystore_client_impl.h>
+
+namespace android {
+namespace os {
+namespace incidentd {
+
+class IncidentKeyStore {
+public:
+    static IncidentKeyStore& getInstance();
+
+    IncidentKeyStore(keystore::KeystoreClient* client) : mClient(client) {}
+
+    /**
+     * Encrypt the plainText and output the encrypted message.
+     *
+     * Returns true on success and false otherwise.
+     * If the key has not been created yet, it will generate the key in KeyMaster.
+     */
+    bool encrypt(const std::string& plainText, int32_t flags, std::string* output);
+
+    /**
+     * Decrypt and output the decrypted message.
+     *
+     * Returns true on success and false otherwise.
+     */
+    bool decrypt(const std::string& encryptedData, std::string* output);
+
+private:
+    std::unique_ptr<keystore::KeystoreClient> mClient;
+    std::mutex mMutex;
+    keystore::KeyStoreNativeReturnCode generateKeyLocked(const std::string& name, int32_t flags);
+};
+
+}  // namespace incidentd
+}  // namespace os
+}  // namespace android
diff --git a/cmds/incidentd/src/cipher/ProtoEncryption.cpp b/cmds/incidentd/src/cipher/ProtoEncryption.cpp
new file mode 100644
index 000000000000..493796d2af4d
--- /dev/null
+++ b/cmds/incidentd/src/cipher/ProtoEncryption.cpp
@@ -0,0 +1,139 @@
+/*
+ * Copyright (C) 2019 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.
+ */
+
+#define DEBUG true  // STOPSHIP if true
+#include "Log.h"
+
+#include "ProtoEncryption.h"
+
+#include <android/util/protobuf.h>
+
+#include "IncidentKeyStore.h"
+
+namespace android {
+namespace os {
+namespace incidentd {
+
+using android::util::FIELD_COUNT_REPEATED;
+using android::util::FIELD_TYPE_STRING;
+using android::util::ProtoOutputStream;
+using android::util::ProtoReader;
+using std::string;
+
+static const int FIELD_ID_BLOCK = 1;
+
+size_t ProtoEncryptor::encrypt() {
+    string block;
+    int i = 0;
+    // Read at most sBlockSize at a time and encrypt.
+    while (mReader->readBuffer() != NULL) {
+        size_t readBytes =
+                mReader->currentToRead() > sBlockSize ? sBlockSize : mReader->currentToRead();
+        block.resize(readBytes);
+        std::memcpy(block.data(), mReader->readBuffer(), readBytes);
+
+        string encrypted;
+        if (IncidentKeyStore::getInstance().encrypt(block, 0, &encrypted)) {
+            mOutputStream.write(FIELD_TYPE_STRING | FIELD_ID_BLOCK | FIELD_COUNT_REPEATED,
+                                encrypted);
+            VLOG("Block %d Encryption: original %lld now %lld", i++, (long long)readBytes,
+                 (long long)encrypted.length());
+            mReader->move(readBytes);
+        } else {
+            return 0;
+        }
+    }
+    return mOutputStream.size();
+}
+
+status_t ProtoEncryptor::flush(int fd) {
+    if (!mOutputStream.flush(fd)) {
+        return BAD_VALUE;
+    }
+    return NO_ERROR;
+}
+
+status_t ProtoDecryptor::readOneBlock(string* output) {
+    if (!mReader->hasNext()) {
+        return NO_ERROR;
+    }
+    uint64_t fieldTag = mReader->readRawVarint();
+    uint32_t fieldId = read_field_id(fieldTag);
+    uint8_t wireType = read_wire_type(fieldTag);
+    if (wireType == WIRE_TYPE_LENGTH_DELIMITED) {
+        // Read this section from the reader into an FdBuffer
+        size_t sectionSize = mReader->readRawVarint();
+        output->resize(sectionSize);
+        size_t pos = 0;
+        while (pos < sectionSize && mReader->readBuffer() != NULL) {
+            size_t toRead = (sectionSize - pos) > mReader->currentToRead()
+                                    ? mReader->currentToRead()
+                                    : (sectionSize - pos);
+            std::memcpy(&((output->data())[pos]), mReader->readBuffer(), toRead);
+            pos += toRead;
+            mReader->move(toRead);
+        }
+        if (pos != sectionSize) {
+            return BAD_VALUE;
+            ALOGE("Failed to read one block");
+        }
+    } else {
+        return BAD_VALUE;
+    }
+    return NO_ERROR;
+}
+
+status_t ProtoDecryptor::decryptAndFlush(FdBuffer* out) {
+    size_t mStartBytes = mReader->bytesRead();
+    size_t bytesRead = 0;
+    int i = 0;
+    status_t err = NO_ERROR;
+    // Let's read until we read mTotalSize. If any error occurs before that, make sure to move the
+    // read pointer so the caller can continue to read the following sections.
+    while (bytesRead < mTotalSize) {
+        string block;
+        err = readOneBlock(&block);
+        bytesRead = mReader->bytesRead() - mStartBytes;
+
+        if (err != NO_ERROR) {
+            break;
+        }
+
+        if (block.length() == 0) {
+            VLOG("Done reading all blocks");
+            break;
+        }
+
+        string decryptedBlock;
+        if ((IncidentKeyStore::getInstance()).decrypt(block, &decryptedBlock)) {
+            VLOG("Block %d Original Size %lu Decrypted size %lu", i++,
+                 (unsigned long)block.length(), (unsigned long)decryptedBlock.length());
+            out->write(reinterpret_cast<uint8_t*>(decryptedBlock.data()), decryptedBlock.length());
+        } else {
+            err = BAD_VALUE;
+            break;
+        }
+    }
+
+    if (bytesRead < mTotalSize) {
+        mReader->move(mTotalSize - bytesRead);
+    }
+    return err;
+}
+
+}  // namespace incidentd
+}  // namespace os
+}  // namespace android
diff --git a/cmds/incidentd/src/cipher/ProtoEncryption.h b/cmds/incidentd/src/cipher/ProtoEncryption.h
new file mode 100644
index 000000000000..5b72ca88ec64
--- /dev/null
+++ b/cmds/incidentd/src/cipher/ProtoEncryption.h
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2019 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.
+ */
+#pragma once
+
+#include <android/util/ProtoOutputStream.h>
+#include <android/util/ProtoReader.h>
+#include <frameworks/base/cmds/incidentd/src/cipher/cipher_blocks.pb.h>
+
+#include "FdBuffer.h"
+
+namespace android {
+namespace os {
+namespace incidentd {
+
+// PlainText IncidentReport format
+// [section1_header(id, size, type)][section1_data] ...
+
+// Let's say section1 needs encryption
+// After encryption, it becomes
+// [section1_header(id, encrypted_size, type)][[cipher_block][cipher_block][cipher_block]..]
+
+// When clients read the report, it's decrypted, and written in its original format
+
+/**
+ * Takes a ProtoReader, encrypts its whole content -- which is one section, and flush to
+ * a file descriptor.
+ * The underlying encryption is done using Keystore binder APIs. We encrypt the data
+ * in blocks, and write to the file in android.os.incidentd.CipherBlocks format.
+ */
+class ProtoEncryptor {
+public:
+    ProtoEncryptor(const sp<android::util::ProtoReader>& reader) : mReader(reader){};
+
+    // Encrypt the data from ProtoReader, and store in CipherBlocks format.
+    // return the size of CipherBlocks.
+    size_t encrypt();
+
+    status_t flush(int fd);
+
+private:
+    static const size_t sBlockSize = 8 * 1024;
+    const sp<android::util::ProtoReader> mReader;
+    android::util::ProtoOutputStream mOutputStream;
+};
+
+// Read data from ProtoReader, which is in CipherBlocks proto format. Parse and decrypt
+// block by block.
+class ProtoDecryptor {
+public:
+    ProtoDecryptor(const sp<android::util::ProtoReader>& reader, size_t size)
+        : mReader(reader), mTotalSize(size){};
+    status_t decryptAndFlush(FdBuffer* out);
+
+private:
+    const sp<android::util::ProtoReader> mReader;
+
+    // Total size in bytes we should read from ProtoReader.
+    const size_t mTotalSize;
+
+    // Read one cipher block from ProtoReader, instead of reading the whole content
+    // and parse to CipherBlocks which could be huge.
+    status_t readOneBlock(std::string* output);
+};
+
+}  // namespace incidentd
+}  // namespace os
+}  // namespace android
diff --git a/cmds/incidentd/src/cipher/cipher_blocks.proto b/cmds/incidentd/src/cipher/cipher_blocks.proto
new file mode 100644
index 000000000000..5c7ed242c7a5
--- /dev/null
+++ b/cmds/incidentd/src/cipher/cipher_blocks.proto
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2019 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.
+ */
+
+syntax = "proto2";
+
+package android.os.incidentd;
+
+// This proto is never instantiated anywhere. It only exists to keep a record of the format of the
+// encrypted data on disk.
+message CipherBlocks {
+    repeated string blocks = 1;
+}