Decrypt FBE on 9.0 (backwards compatible)
Building in 9.0 may require you to add a flag to your twrp fstab
with the fileencryption details like:
fileencryption=ice:aes-256-heh
Verify this against your device's stock fstab of course.
Change-Id: If9286f5d5787280814daca9fbc8f5191ff26a839
diff --git a/crypto/ext4crypt/Keymaster4.cpp b/crypto/ext4crypt/Keymaster4.cpp
new file mode 100644
index 0000000..e25d0c4
--- /dev/null
+++ b/crypto/ext4crypt/Keymaster4.cpp
@@ -0,0 +1,352 @@
+/*
+ * Copyright (C) 2016 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 "Keymaster4.h"
+
+//#include <android-base/logging.h>
+#include <keymasterV4_0/authorization_set.h>
+#include <keymasterV4_0/keymaster_utils.h>
+
+#include <iostream>
+#define LOG(x) std::cout
+#define PLOG(x) std::cout
+
+namespace android {
+namespace vold {
+
+using ::android::hardware::hidl_string;
+using ::android::hardware::hidl_vec;
+using ::android::hardware::keymaster::V4_0::SecurityLevel;
+
+KeymasterOperation::~KeymasterOperation() {
+ if (mDevice) mDevice->abort(mOpHandle);
+}
+
+bool KeymasterOperation::updateCompletely(const char* input, size_t inputLen,
+ const std::function<void(const char*, size_t)> consumer) {
+ uint32_t inputConsumed = 0;
+
+ km::ErrorCode km_error;
+ auto hidlCB = [&](km::ErrorCode ret, uint32_t inputConsumedDelta,
+ const hidl_vec<km::KeyParameter>& /*ignored*/,
+ const hidl_vec<uint8_t>& _output) {
+ km_error = ret;
+ if (km_error != km::ErrorCode::OK) return;
+ inputConsumed += inputConsumedDelta;
+ consumer(reinterpret_cast<const char*>(&_output[0]), _output.size());
+ };
+
+ while (inputConsumed != inputLen) {
+ size_t toRead = static_cast<size_t>(inputLen - inputConsumed);
+ auto inputBlob = km::support::blob2hidlVec(
+ reinterpret_cast<const uint8_t*>(&input[inputConsumed]), toRead);
+ auto error = mDevice->update(mOpHandle, hidl_vec<km::KeyParameter>(), inputBlob,
+ km::HardwareAuthToken(), km::VerificationToken(), hidlCB);
+ if (!error.isOk()) {
+ LOG(ERROR) << "update failed: " << error.description() << std::endl;
+ mDevice = nullptr;
+ return false;
+ }
+ if (km_error != km::ErrorCode::OK) {
+ LOG(ERROR) << "update failed, code " << int32_t(km_error) << std::endl;
+ mDevice = nullptr;
+ return false;
+ }
+ if (inputConsumed > inputLen) {
+ LOG(ERROR) << "update reported too much input consumed" << std::endl;
+ mDevice = nullptr;
+ return false;
+ }
+ }
+ return true;
+}
+
+bool KeymasterOperation::finish(std::string* output) {
+ km::ErrorCode km_error;
+ auto hidlCb = [&](km::ErrorCode ret, const hidl_vec<km::KeyParameter>& /*ignored*/,
+ const hidl_vec<uint8_t>& _output) {
+ km_error = ret;
+ if (km_error != km::ErrorCode::OK) return;
+ if (output) output->assign(reinterpret_cast<const char*>(&_output[0]), _output.size());
+ };
+ auto error = mDevice->finish(mOpHandle, hidl_vec<km::KeyParameter>(), hidl_vec<uint8_t>(),
+ hidl_vec<uint8_t>(), km::HardwareAuthToken(),
+ km::VerificationToken(), hidlCb);
+ mDevice = nullptr;
+ if (!error.isOk()) {
+ LOG(ERROR) << "finish failed: " << error.description() << std::endl;
+ return false;
+ }
+ if (km_error != km::ErrorCode::OK) {
+ LOG(ERROR) << "finish failed, code " << int32_t(km_error) << std::endl;
+ return false;
+ }
+ return true;
+}
+
+/* static */ bool Keymaster::hmacKeyGenerated = false;
+
+Keymaster::Keymaster() {
+ auto devices = KmDevice::enumerateAvailableDevices();
+ if (!hmacKeyGenerated) {
+ KmDevice::performHmacKeyAgreement(devices);
+ hmacKeyGenerated = true;
+ }
+ for (auto& dev : devices) {
+ // Do not use StrongBox for device encryption / credential encryption. If a security chip
+ // is present it will have Weaver, which already strengthens CE. We get no additional
+ // benefit from using StrongBox here, so skip it.
+ if (dev->halVersion().securityLevel != SecurityLevel::STRONGBOX) {
+ mDevice = std::move(dev);
+ break;
+ }
+ }
+ if (!mDevice) return;
+ auto& version = mDevice->halVersion();
+ LOG(INFO) << "Using " << version.keymasterName << " from " << version.authorName
+ << " for encryption. Security level: " << toString(version.securityLevel)
+ << ", HAL: " << mDevice->descriptor() << "/" << mDevice->instanceName() << std::endl;
+}
+
+bool Keymaster::generateKey(const km::AuthorizationSet& inParams, std::string* key) {
+ km::ErrorCode km_error;
+ auto hidlCb = [&](km::ErrorCode ret, const hidl_vec<uint8_t>& keyBlob,
+ const km::KeyCharacteristics& /*ignored*/) {
+ km_error = ret;
+ if (km_error != km::ErrorCode::OK) return;
+ if (key) key->assign(reinterpret_cast<const char*>(&keyBlob[0]), keyBlob.size());
+ };
+
+ auto error = mDevice->generateKey(inParams.hidl_data(), hidlCb);
+ if (!error.isOk()) {
+ LOG(ERROR) << "generate_key failed: " << error.description() << std::endl;
+ return false;
+ }
+ if (km_error != km::ErrorCode::OK) {
+ LOG(ERROR) << "generate_key failed, code " << int32_t(km_error) << std::endl;
+ return false;
+ }
+ return true;
+}
+
+bool Keymaster::deleteKey(const std::string& key) {
+ LOG(ERROR) << "not actually deleting key\n";
+ return true;
+ auto keyBlob = km::support::blob2hidlVec(key);
+ auto error = mDevice->deleteKey(keyBlob);
+ if (!error.isOk()) {
+ LOG(ERROR) << "delete_key failed: " << error.description();
+ return false;
+ }
+ if (error != km::ErrorCode::OK) {
+ LOG(ERROR) << "delete_key failed, code " << int32_t(km::ErrorCode(error));
+ return false;
+ }
+ return true;
+}
+
+bool Keymaster::upgradeKey(const std::string& oldKey, const km::AuthorizationSet& inParams,
+ std::string* newKey) {
+ auto oldKeyBlob = km::support::blob2hidlVec(oldKey);
+ km::ErrorCode km_error;
+ auto hidlCb = [&](km::ErrorCode ret, const hidl_vec<uint8_t>& upgradedKeyBlob) {
+ km_error = ret;
+ if (km_error != km::ErrorCode::OK) return;
+ if (newKey)
+ newKey->assign(reinterpret_cast<const char*>(&upgradedKeyBlob[0]),
+ upgradedKeyBlob.size());
+ };
+ auto error = mDevice->upgradeKey(oldKeyBlob, inParams.hidl_data(), hidlCb);
+ if (!error.isOk()) {
+ LOG(ERROR) << "upgrade_key failed: " << error.description() << std::endl;
+ return false;
+ }
+ if (km_error != km::ErrorCode::OK) {
+ LOG(ERROR) << "upgrade_key failed, code " << int32_t(km_error) << std::endl;
+ return false;
+ }
+ return true;
+}
+
+KeymasterOperation Keymaster::begin(km::KeyPurpose purpose, const std::string& key,
+ const km::AuthorizationSet& inParams,
+ const km::HardwareAuthToken& authToken,
+ km::AuthorizationSet* outParams) {
+ auto keyBlob = km::support::blob2hidlVec(key);
+ uint64_t mOpHandle;
+ km::ErrorCode km_error;
+
+ auto hidlCb = [&](km::ErrorCode ret, const hidl_vec<km::KeyParameter>& _outParams,
+ uint64_t operationHandle) {
+ km_error = ret;
+ if (km_error != km::ErrorCode::OK) return;
+ if (outParams) *outParams = _outParams;
+ mOpHandle = operationHandle;
+ };
+
+ auto error = mDevice->begin(purpose, keyBlob, inParams.hidl_data(), authToken, hidlCb);
+ if (!error.isOk()) {
+ LOG(ERROR) << "begin failed: " << error.description() << std::endl;
+ return KeymasterOperation(km::ErrorCode::UNKNOWN_ERROR);
+ }
+ if (km_error != km::ErrorCode::OK) {
+ LOG(ERROR) << "begin failed, code " << int32_t(km_error) << std::endl;
+ return KeymasterOperation(km_error);
+ }
+ return KeymasterOperation(mDevice.get(), mOpHandle);
+}
+
+bool Keymaster::isSecure() {
+ return mDevice->halVersion().securityLevel != km::SecurityLevel::SOFTWARE;
+}
+
+} // namespace vold
+} // namespace android
+
+using namespace ::android::vold;
+
+int keymaster_compatibility_cryptfs_scrypt() {
+ Keymaster dev;
+ if (!dev) {
+ LOG(ERROR) << "Failed to initiate keymaster session" << std::endl;
+ return -1;
+ }
+ return dev.isSecure();
+}
+
+static bool write_string_to_buf(const std::string& towrite, uint8_t* buffer, uint32_t buffer_size,
+ uint32_t* out_size) {
+ if (!buffer || !out_size) {
+ LOG(ERROR) << "Missing target pointers" << std::endl;
+ return false;
+ }
+ *out_size = towrite.size();
+ if (buffer_size < towrite.size()) {
+ LOG(ERROR) << "Buffer too small " << buffer_size << " < " << towrite.size() << std::endl;
+ return false;
+ }
+ memset(buffer, '\0', buffer_size);
+ std::copy(towrite.begin(), towrite.end(), buffer);
+ return true;
+}
+
+static km::AuthorizationSet keyParams(uint32_t rsa_key_size, uint64_t rsa_exponent,
+ uint32_t ratelimit) {
+ return km::AuthorizationSetBuilder()
+ .RsaSigningKey(rsa_key_size, rsa_exponent)
+ .NoDigestOrPadding()
+ .Authorization(km::TAG_BLOB_USAGE_REQUIREMENTS, km::KeyBlobUsageRequirements::STANDALONE)
+ .Authorization(km::TAG_NO_AUTH_REQUIRED)
+ .Authorization(km::TAG_MIN_SECONDS_BETWEEN_OPS, ratelimit);
+}
+
+int keymaster_create_key_for_cryptfs_scrypt(uint32_t rsa_key_size, uint64_t rsa_exponent,
+ uint32_t ratelimit, uint8_t* key_buffer,
+ uint32_t key_buffer_size, uint32_t* key_out_size) {
+ if (key_out_size) {
+ *key_out_size = 0;
+ }
+ Keymaster dev;
+ if (!dev) {
+ LOG(ERROR) << "Failed to initiate keymaster session" << std::endl;
+ return -1;
+ }
+ std::string key;
+ if (!dev.generateKey(keyParams(rsa_key_size, rsa_exponent, ratelimit), &key)) return -1;
+ if (!write_string_to_buf(key, key_buffer, key_buffer_size, key_out_size)) return -1;
+ return 0;
+}
+
+int keymaster_upgrade_key_for_cryptfs_scrypt(uint32_t rsa_key_size, uint64_t rsa_exponent,
+ uint32_t ratelimit, const uint8_t* key_blob,
+ size_t key_blob_size, uint8_t* key_buffer,
+ uint32_t key_buffer_size, uint32_t* key_out_size) {
+ if (key_out_size) {
+ *key_out_size = 0;
+ }
+ Keymaster dev;
+ if (!dev) {
+ LOG(ERROR) << "Failed to initiate keymaster session" << std::endl;
+ return -1;
+ }
+ std::string old_key(reinterpret_cast<const char*>(key_blob), key_blob_size);
+ std::string new_key;
+ if (!dev.upgradeKey(old_key, keyParams(rsa_key_size, rsa_exponent, ratelimit), &new_key))
+ return -1;
+ if (!write_string_to_buf(new_key, key_buffer, key_buffer_size, key_out_size)) return -1;
+ return 0;
+}
+
+KeymasterSignResult keymaster_sign_object_for_cryptfs_scrypt(
+ const uint8_t* key_blob, size_t key_blob_size, uint32_t ratelimit, const uint8_t* object,
+ const size_t object_size, uint8_t** signature_buffer, size_t* signature_buffer_size) {
+ Keymaster dev;
+ if (!dev) {
+ LOG(ERROR) << "Failed to initiate keymaster session" << std::endl;
+ return KeymasterSignResult::error;
+ }
+ if (!key_blob || !object || !signature_buffer || !signature_buffer_size) {
+ LOG(ERROR) << __FILE__ << ":" << __LINE__ << ":Invalid argument" << std::endl;
+ return KeymasterSignResult::error;
+ }
+
+ km::AuthorizationSet outParams;
+ std::string key(reinterpret_cast<const char*>(key_blob), key_blob_size);
+ std::string input(reinterpret_cast<const char*>(object), object_size);
+ std::string output;
+ KeymasterOperation op;
+
+ auto paramBuilder = km::AuthorizationSetBuilder().NoDigestOrPadding();
+ while (true) {
+ op = dev.begin(km::KeyPurpose::SIGN, key, paramBuilder, km::HardwareAuthToken(), &outParams);
+ if (op.errorCode() == km::ErrorCode::KEY_RATE_LIMIT_EXCEEDED) {
+ sleep(ratelimit);
+ continue;
+ } else
+ break;
+ }
+
+ if (op.errorCode() == km::ErrorCode::KEY_REQUIRES_UPGRADE) {
+ LOG(ERROR) << "Keymaster key requires upgrade" << std::endl;
+ return KeymasterSignResult::upgrade;
+ }
+
+ if (op.errorCode() != km::ErrorCode::OK) {
+ LOG(ERROR) << "Error starting keymaster signature transaction: " << int32_t(op.errorCode()) << std::endl;
+ return KeymasterSignResult::error;
+ }
+
+ if (!op.updateCompletely(input, &output)) {
+ LOG(ERROR) << "Error sending data to keymaster signature transaction: "
+ << uint32_t(op.errorCode()) << std::endl;
+ return KeymasterSignResult::error;
+ }
+
+ if (!op.finish(&output)) {
+ LOG(ERROR) << "Error finalizing keymaster signature transaction: "
+ << int32_t(op.errorCode()) << std::endl;
+ return KeymasterSignResult::error;
+ }
+
+ *signature_buffer = reinterpret_cast<uint8_t*>(malloc(output.size()));
+ if (*signature_buffer == nullptr) {
+ LOG(ERROR) << "Error allocation buffer for keymaster signature" << std::endl;
+ return KeymasterSignResult::error;
+ }
+ *signature_buffer_size = output.size();
+ std::copy(output.data(), output.data() + output.size(), *signature_buffer);
+ return KeymasterSignResult::ok;
+}