/*

* 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 "KeyStorage.h"

#include "Checkpoint.h"

#include "Keystore.h"

#include "RandUtils.h"

#include "Utils.h"

#include <algorithm>

#include <memory>

#include <mutex>

#include <vector>

#include <errno.h>

#include <stdio.h>

#include <sys/stat.h>

#include <sys/types.h>

#include <sys/wait.h>

#include <unistd.h>

#include <openssl/err.h>

#include <openssl/evp.h>

#include <openssl/sha.h>

#include <android-base/file.h>

#include <android-base/logging.h>

#include <android-base/properties.h>

#include <android-base/unique_fd.h>

#include <cutils/properties.h>

namespace android {

namespace vold {

const KeyAuthentication kEmptyAuthentication{""};

static constexpr size_t GCM_NONCE_BYTES = 12;

static constexpr size_t GCM_MAC_BYTES = 16;

static constexpr size_t SECDISCARDABLE_BYTES = 1 << 14;

static const char* kCurrentVersion = "1";

static const char* kRmPath = "/system/bin/rm";

static const char* kSecdiscardPath = "/system/bin/secdiscard";

static const char* kHashPrefix_secdiscardable = "Android secdiscardable SHA512";

static const char* kHashPrefix_keygen = "Android key wrapping key generation SHA512";

static const char* kFn_encrypted_key = "encrypted_key";

static const char* kFn_keymaster_key_blob = "keymaster_key_blob";

static const char* kFn_keymaster_key_blob_upgraded = "keymaster_key_blob_upgraded";

static const char* kFn_secdiscardable = "secdiscardable";

static const char* kFn_version = "version";

// Note: old key directories may contain a file named "stretching".

namespace {

// Storage binding info for ensuring key encryption keys include a

// platform-provided seed in their derivation.

struct StorageBindingInfo {

enum class State {

UNINITIALIZED,

IN_USE, // key storage keys are bound to seed

NOT_USED, // key storage keys are NOT bound to seed

};

// Binding seed mixed into all key storage keys.

std::vector<uint8_t> seed;

// State tracker for the key storage key binding.

State state = State::UNINITIALIZED;

std::mutex guard;

};

// Never freed as the dtor is non-trivial.

StorageBindingInfo& storage_binding_info = *new StorageBindingInfo;

} // namespace

static bool checkSize(const std::string& kind, size_t actual, size_t expected) {

if (actual != expected) {

LOG(ERROR) << "Wrong number of bytes in " << kind << ", expected " << expected << " got "

<< actual;

return false;

}

return true;

}

static void hashWithPrefix(char const* prefix, const std::string& tohash, std::string* res) {

SHA512_CTX c;

SHA512_Init(&c);

// Personalise the hashing by introducing a fixed prefix.

// Hashing applications should use personalization except when there is a

// specific reason not to; see section 4.11 of https://www.schneier.com/skein1.3.pdf

std::string hashingPrefix = prefix;

hashingPrefix.resize(SHA512_CBLOCK);

SHA512_Update(&c, hashingPrefix.data(), hashingPrefix.size());

SHA512_Update(&c, tohash.data(), tohash.size());

res->assign(SHA512_DIGEST_LENGTH, '\0');

SHA512_Final(reinterpret_cast<uint8_t*>(&(*res)[0]), &c);

}

static bool generateKeyStorageKey(Keystore& keystore, const std::string& appId, std::string* key) {

auto paramBuilder = km::AuthorizationSetBuilder()

.AesEncryptionKey(AES_KEY_BYTES * 8)

.GcmModeMinMacLen(GCM_MAC_BYTES * 8)

.Authorization(km::TAG_APPLICATION_ID, appId)

.Authorization(km::TAG_NO_AUTH_REQUIRED);

LOG(DEBUG) << "Generating \"key storage\" key";

auto paramsWithRollback = paramBuilder;

paramsWithRollback.Authorization(km::TAG_ROLLBACK_RESISTANCE);

if (!keystore.generateKey(paramsWithRollback, key)) {

LOG(WARNING) << "Failed to generate rollback-resistant key. This is expected if keystore "

"doesn't support rollback resistance. Falling back to "

"non-rollback-resistant key.";

if (!keystore.generateKey(paramBuilder, key)) return false;

}

return true;

}

static km::AuthorizationSet beginParams(const std::string& appId) {

return km::AuthorizationSetBuilder()

.GcmModeMacLen(GCM_MAC_BYTES * 8)

.Authorization(km::TAG_APPLICATION_ID, appId);

}

static bool readFileToString(const std::string& filename, std::string* result) {

if (!android::base::ReadFileToString(filename, result)) {

PLOG(ERROR) << "Failed to read from " << filename;

return false;

}

return true;

}

static bool readRandomBytesOrLog(size_t count, std::string* out) {

auto status = ReadRandomBytes(count, *out);

if (status != OK) {

LOG(ERROR) << "Random read failed with status: " << status;

return false;

}

return true;

}

bool createSecdiscardable(const std::string& filename, std::string* hash) {

std::string secdiscardable;

if (!readRandomBytesOrLog(SECDISCARDABLE_BYTES, &secdiscardable)) return false;

if (!writeStringToFile(secdiscardable, filename)) return false;

hashWithPrefix(kHashPrefix_secdiscardable, secdiscardable, hash);

return true;

}

bool readSecdiscardable(const std::string& filename, std::string* hash) {

if (pathExists(filename)) {

std::string secdiscardable;

if (!readFileToString(filename, &secdiscardable)) return false;

hashWithPrefix(kHashPrefix_secdiscardable, secdiscardable, hash);

} else {

*hash = "";

}

return true;

}

static std::mutex key_upgrade_lock;

// List of key directories that have had their Keystore key upgraded during

// this boot and written to "keymaster_key_blob_upgraded", but replacing the old

// key was delayed due to an active checkpoint. Protected by key_upgrade_lock.

// A directory can be in this list at most once.

static std::vector<std::string> key_dirs_to_commit;

// Replaces |dir|/keymaster_key_blob with |dir|/keymaster_key_blob_upgraded and

// deletes the old key from Keystore.

static bool CommitUpgradedKey(Keystore& keystore, const std::string& dir) {

auto blob_file = dir + "/" + kFn_keymaster_key_blob;

auto upgraded_blob_file = dir + "/" + kFn_keymaster_key_blob_upgraded;

std::string blob;

if (!readFileToString(blob_file, &blob)) return false;

if (rename(upgraded_blob_file.c_str(), blob_file.c_str()) != 0) {

PLOG(ERROR) << "Failed to rename " << upgraded_blob_file << " to " << blob_file;

return false;

}

// Ensure that the rename is persisted before deleting the Keystore key.

if (!FsyncDirectory(dir)) return false;

if (!keystore || !keystore.deleteKey(blob)) {

LOG(WARNING) << "Failed to delete old key " << blob_file

<< " from Keystore; continuing anyway";

// Continue on, but the space in Keystore used by the old key won't be freed.

}

return true;

}

void DeferredCommitKeystoreKeys() {

LOG(INFO) << "Committing upgraded Keystore keys";

Keystore keystore;

if (!keystore) {

LOG(ERROR) << "Failed to open Keystore; old keys won't be deleted from Keystore";

// Continue on, but the space in Keystore used by the old keys won't be freed.

}

std::lock_guard<std::mutex> lock(key_upgrade_lock);

for (auto& dir : key_dirs_to_commit) {

LOG(INFO) << "Committing upgraded Keystore key for " << dir;

CommitUpgradedKey(keystore, dir);

}

key_dirs_to_commit.clear();

LOG(INFO) << "Done committing upgraded Keystore keys";

}

// Returns true if the Keystore key in |dir| has already been upgraded and is

// pending being committed. Assumes that key_upgrade_lock is held.

static bool IsKeyCommitPending(const std::string& dir) {

for (const auto& dir_to_commit : key_dirs_to_commit) {

if (IsSameFile(dir, dir_to_commit)) return true;

}

return false;

}

// Schedules the upgraded Keystore key in |dir| to be committed later. Assumes

// that key_upgrade_lock is held and that a commit isn't already pending for the

// directory.

static void ScheduleKeyCommit(const std::string& dir) {

key_dirs_to_commit.push_back(dir);

}

static void CancelPendingKeyCommit(const std::string& dir) {

std::lock_guard<std::mutex> lock(key_upgrade_lock);

for (auto it = key_dirs_to_commit.begin(); it != key_dirs_to_commit.end(); it++) {

if (IsSameFile(*it, dir)) {

LOG(DEBUG) << "Cancelling pending commit of upgraded key " << dir

<< " because it is being destroyed";

key_dirs_to_commit.erase(it);

break;

}

}

}

bool RenameKeyDir(const std::string& old_name, const std::string& new_name) {

std::lock_guard<std::mutex> lock(key_upgrade_lock);

// Find the entry in key_dirs_to_commit (if any) for this directory so that

// we can update it if the rename succeeds. We don't allow duplicates in

// this list, so there can be at most one such entry.

auto it = key_dirs_to_commit.begin();

for (; it != key_dirs_to_commit.end(); it++) {

if (IsSameFile(old_name, *it)) break;

}

if (rename(old_name.c_str(), new_name.c_str()) != 0) {

PLOG(ERROR) << "Failed to rename key directory \"" << old_name << "\" to \"" << new_name

<< "\"";

return false;

}

if (it != key_dirs_to_commit.end()) *it = new_name;

return true;

}

// Deletes a leftover upgraded key, if present. An upgraded key can be left

// over if an update failed, or if we rebooted before committing the key in a

// freak accident. Either way, we can re-upgrade the key if we need to.

static void DeleteUpgradedKey(Keystore& keystore, const std::string& path) {

if (pathExists(path)) {

LOG(DEBUG) << "Deleting leftover upgraded key " << path;

std::string blob;

if (!android::base::ReadFileToString(path, &blob)) {

LOG(WARNING) << "Failed to read leftover upgraded key " << path

<< "; continuing anyway";

} else if (!keystore.deleteKey(blob)) {

LOG(WARNING) << "Failed to delete leftover upgraded key " << path

<< " from Keystore; continuing anyway";

}

if (unlink(path.c_str()) != 0) {

LOG(WARNING) << "Failed to unlink leftover upgraded key " << path

<< "; continuing anyway";

}

}

}

// Begins a Keystore operation using the key stored in |dir|.

static KeystoreOperation BeginKeystoreOp(Keystore& keystore, const std::string& dir,

const km::AuthorizationSet& keyParams,

const km::AuthorizationSet& opParams,

km::AuthorizationSet* outParams) {

km::AuthorizationSet inParams(keyParams);

inParams.append(opParams.begin(), opParams.end());

auto blob_file = dir + "/" + kFn_keymaster_key_blob;

auto upgraded_blob_file = dir + "/" + kFn_keymaster_key_blob_upgraded;

std::lock_guard<std::mutex> lock(key_upgrade_lock);

std::string blob;

bool already_upgraded = IsKeyCommitPending(dir);

if (already_upgraded) {

LOG(DEBUG)

<< blob_file

<< " was already upgraded and is waiting to be committed; using the upgraded blob";

if (!readFileToString(upgraded_blob_file, &blob)) return KeystoreOperation();

} else {

DeleteUpgradedKey(keystore, upgraded_blob_file);

if (!readFileToString(blob_file, &blob)) return KeystoreOperation();

}

auto opHandle = keystore.begin(blob, inParams, outParams);

if (!opHandle) return opHandle;

// If key blob wasn't upgraded, nothing left to do.

if (!opHandle.getUpgradedBlob()) return opHandle;

if (already_upgraded) {

LOG(ERROR) << "Unexpected case; already-upgraded key " << upgraded_blob_file

<< " still requires upgrade";

return KeystoreOperation();

}

LOG(INFO) << "Upgrading key: " << blob_file;

if (!writeStringToFile(*opHandle.getUpgradedBlob(), upgraded_blob_file))

return KeystoreOperation();

if (cp_needsCheckpoint()) {

LOG(INFO) << "Wrote upgraded key to " << upgraded_blob_file

<< "; delaying commit due to checkpoint";

ScheduleKeyCommit(dir);

} else {

if (!CommitUpgradedKey(keystore, dir)) return KeystoreOperation();

LOG(INFO) << "Key upgraded: " << blob_file;

}

return opHandle;

}

static bool encryptWithKeystoreKey(Keystore& keystore, const std::string& dir,

const km::AuthorizationSet& keyParams, const KeyBuffer& message,

std::string* ciphertext) {

km::AuthorizationSet opParams =

km::AuthorizationSetBuilder().Authorization(km::TAG_PURPOSE, km::KeyPurpose::ENCRYPT);

km::AuthorizationSet outParams;

auto opHandle = BeginKeystoreOp(keystore, dir, keyParams, opParams, &outParams);

if (!opHandle) return false;

auto nonceBlob = outParams.GetTagValue(km::TAG_NONCE);

if (!nonceBlob) {

LOG(ERROR) << "GCM encryption but no nonce generated";

return false;

}

// nonceBlob here is just a pointer into existing data, must not be freed

std::string nonce(nonceBlob.value().get().begin(), nonceBlob.value().get().end());

if (!checkSize("nonce", nonce.size(), GCM_NONCE_BYTES)) return false;

std::string body;

if (!opHandle.updateCompletely(message, &body)) return false;

std::string mac;

if (!opHandle.finish(&mac)) return false;

if (!checkSize("mac", mac.size(), GCM_MAC_BYTES)) return false;

*ciphertext = nonce + body + mac;

return true;

}

static bool decryptWithKeystoreKey(Keystore& keystore, const std::string& dir,

const km::AuthorizationSet& keyParams,

const std::string& ciphertext, KeyBuffer* message) {

const std::string nonce = ciphertext.substr(0, GCM_NONCE_BYTES);

auto bodyAndMac = ciphertext.substr(GCM_NONCE_BYTES);

auto opParams = km::AuthorizationSetBuilder()

.Authorization(km::TAG_NONCE, nonce)

.Authorization(km::TAG_PURPOSE, km::KeyPurpose::DECRYPT);

auto opHandle = BeginKeystoreOp(keystore, dir, keyParams, opParams, nullptr);

if (!opHandle) return false;

if (!opHandle.updateCompletely(bodyAndMac, message)) return false;

if (!opHandle.finish(nullptr)) return false;

return true;

}

static std::string generateAppId(const KeyAuthentication& auth,

const std::string& secdiscardable_hash) {

std::string appId = secdiscardable_hash + auth.secret;

const std::lock_guard<std::mutex> scope_lock(storage_binding_info.guard);

switch (storage_binding_info.state) {

case StorageBindingInfo::State::UNINITIALIZED:

storage_binding_info.state = StorageBindingInfo::State::NOT_USED;

break;

case StorageBindingInfo::State::IN_USE:

appId.append(storage_binding_info.seed.begin(), storage_binding_info.seed.end());

break;

case StorageBindingInfo::State::NOT_USED:

// noop

break;

}

return appId;

}

static void logOpensslError() {

LOG(ERROR) << "Openssl error: " << ERR_get_error();

}

static bool encryptWithoutKeystore(const std::string& preKey, const KeyBuffer& plaintext,

std::string* ciphertext) {

std::string key;

hashWithPrefix(kHashPrefix_keygen, preKey, &key);

key.resize(AES_KEY_BYTES);

if (!readRandomBytesOrLog(GCM_NONCE_BYTES, ciphertext)) return false;

auto ctx = std::unique_ptr<EVP_CIPHER_CTX, decltype(&::EVP_CIPHER_CTX_free)>(

EVP_CIPHER_CTX_new(), EVP_CIPHER_CTX_free);

if (!ctx) {

logOpensslError();

return false;

}

if (1 != EVP_EncryptInit_ex(ctx.get(), EVP_aes_256_gcm(), NULL,

reinterpret_cast<const uint8_t*>(key.data()),

reinterpret_cast<const uint8_t*>(ciphertext->data()))) {

logOpensslError();

return false;

}

ciphertext->resize(GCM_NONCE_BYTES + plaintext.size() + GCM_MAC_BYTES);

int outlen;

if (1 != EVP_EncryptUpdate(

ctx.get(), reinterpret_cast<uint8_t*>(&(*ciphertext)[0] + GCM_NONCE_BYTES),

&outlen, reinterpret_cast<const uint8_t*>(plaintext.data()), plaintext.size())) {

logOpensslError();

return false;

}

if (outlen != static_cast<int>(plaintext.size())) {

LOG(ERROR) << "GCM ciphertext length should be " << plaintext.size() << " was " << outlen;

return false;

}

if (1 != EVP_EncryptFinal_ex(

ctx.get(),

reinterpret_cast<uint8_t*>(&(*ciphertext)[0] + GCM_NONCE_BYTES + plaintext.size()),

&outlen)) {

logOpensslError();

return false;

}

if (outlen != 0) {

LOG(ERROR) << "GCM EncryptFinal should be 0, was " << outlen;

return false;

}

if (1 != EVP_CIPHER_CTX_ctrl(ctx.get(), EVP_CTRL_GCM_GET_TAG, GCM_MAC_BYTES,

reinterpret_cast<uint8_t*>(&(*ciphertext)[0] + GCM_NONCE_BYTES +

plaintext.size()))) {

logOpensslError();

return false;

}

return true;

}

static bool decryptWithoutKeystore(const std::string& preKey, const std::string& ciphertext,

KeyBuffer* plaintext) {

if (ciphertext.size() < GCM_NONCE_BYTES + GCM_MAC_BYTES) {

LOG(ERROR) << "GCM ciphertext too small: " << ciphertext.size();

return false;

}

std::string key;

hashWithPrefix(kHashPrefix_keygen, preKey, &key);

key.resize(AES_KEY_BYTES);

auto ctx = std::unique_ptr<EVP_CIPHER_CTX, decltype(&::EVP_CIPHER_CTX_free)>(

EVP_CIPHER_CTX_new(), EVP_CIPHER_CTX_free);

if (!ctx) {

logOpensslError();

return false;

}

if (1 != EVP_DecryptInit_ex(ctx.get(), EVP_aes_256_gcm(), NULL,

reinterpret_cast<const uint8_t*>(key.data()),

reinterpret_cast<const uint8_t*>(ciphertext.data()))) {

logOpensslError();

return false;

}

*plaintext = KeyBuffer(ciphertext.size() - GCM_NONCE_BYTES - GCM_MAC_BYTES);

int outlen;

if (1 != EVP_DecryptUpdate(ctx.get(), reinterpret_cast<uint8_t*>(&(*plaintext)[0]), &outlen,

reinterpret_cast<const uint8_t*>(ciphertext.data() + GCM_NONCE_BYTES),

plaintext->size())) {

logOpensslError();

return false;

}

if (outlen != static_cast<int>(plaintext->size())) {

LOG(ERROR) << "GCM plaintext length should be " << plaintext->size() << " was " << outlen;

return false;

}

if (1 != EVP_CIPHER_CTX_ctrl(ctx.get(), EVP_CTRL_GCM_SET_TAG, GCM_MAC_BYTES,

const_cast<void*>(reinterpret_cast<const void*>(

ciphertext.data() + GCM_NONCE_BYTES + plaintext->size())))) {

logOpensslError();

return false;

}

if (1 != EVP_DecryptFinal_ex(ctx.get(),

reinterpret_cast<uint8_t*>(&(*plaintext)[0] + plaintext->size()),

&outlen)) {

logOpensslError();

return false;

}

if (outlen != 0) {

LOG(ERROR) << "GCM EncryptFinal should be 0, was " << outlen;

return false;

}

return true;

}

// Creates a directory at the given path |dir| and stores |key| in it, in such a

// way that it can only be retrieved via Keystore (if no secret is given in

// |auth|) or with the given secret (if a secret is given in |auth|). In the

// former case, an attempt is made to make the key securely deletable. In the

// latter case, secure deletion is expected to be handled at a higher level.

//

// If a storage binding seed has been set, then the storage binding seed will be

// required to retrieve the key as well.

static bool storeKey(const std::string& dir, const KeyAuthentication& auth, const KeyBuffer& key) {

if (TEMP_FAILURE_RETRY(mkdir(dir.c_str(), 0700)) == -1) {

PLOG(ERROR) << "key mkdir " << dir;

return false;

}

if (!writeStringToFile(kCurrentVersion, dir + "/" + kFn_version)) return false;

std::string secdiscardable_hash;

if (auth.usesKeystore() &&

!createSecdiscardable(dir + "/" + kFn_secdiscardable, &secdiscardable_hash))

return false;

std::string appId = generateAppId(auth, secdiscardable_hash);

std::string encryptedKey;

if (auth.usesKeystore()) {

Keystore keystore;

if (!keystore) return false;

std::string ksKey;

if (!generateKeyStorageKey(keystore, appId, &ksKey)) return false;

if (!writeStringToFile(ksKey, dir + "/" + kFn_keymaster_key_blob)) return false;

km::AuthorizationSet keyParams = beginParams(appId);

if (!encryptWithKeystoreKey(keystore, dir, keyParams, key, &encryptedKey)) {

LOG(ERROR) << "encryptWithKeystoreKey failed";

return false;

}

} else {

if (!encryptWithoutKeystore(appId, key, &encryptedKey)) {

LOG(ERROR) << "encryptWithoutKeystore failed";

return false;

}

}

if (!writeStringToFile(encryptedKey, dir + "/" + kFn_encrypted_key)) return false;

if (!FsyncDirectory(dir)) return false;

return true;

}

bool storeKeyAtomically(const std::string& key_path, const std::string& tmp_path,

const KeyAuthentication& auth, const KeyBuffer& key) {

if (pathExists(key_path)) {

LOG(ERROR) << "Already exists, cannot create key at: " << key_path;

return false;

}

if (pathExists(tmp_path)) {

LOG(DEBUG) << "Already exists, destroying: " << tmp_path;

destroyKey(tmp_path); // May be partially created so ignore errors

}

if (!storeKey(tmp_path, auth, key)) return false;

if (!RenameKeyDir(tmp_path, key_path)) return false;

if (!FsyncParentDirectory(key_path)) return false;

LOG(DEBUG) << "Stored key " << key_path;

return true;

}

bool retrieveKey(const std::string& dir, const KeyAuthentication& auth, KeyBuffer* key) {

std::string version;

if (!readFileToString(dir + "/" + kFn_version, &version)) return false;

if (version != kCurrentVersion) {

LOG(ERROR) << "Version mismatch, expected " << kCurrentVersion << " got " << version;

return false;

}

std::string secdiscardable_hash;

if (!readSecdiscardable(dir + "/" + kFn_secdiscardable, &secdiscardable_hash)) return false;

std::string appId = generateAppId(auth, secdiscardable_hash);

std::string encryptedMessage;

if (!readFileToString(dir + "/" + kFn_encrypted_key, &encryptedMessage)) return false;

if (auth.usesKeystore()) {

Keystore keystore;

if (!keystore) return false;

km::AuthorizationSet keyParams = beginParams(appId);

if (!decryptWithKeystoreKey(keystore, dir, keyParams, encryptedMessage, key)) {

LOG(ERROR) << "decryptWithKeystoreKey failed";

return false;

}

} else {

if (!decryptWithoutKeystore(appId, encryptedMessage, key)) {

LOG(ERROR) << "decryptWithoutKeystore failed";

return false;

}

}

return true;

}

static bool DeleteKeystoreKey(const std::string& blob_file) {

std::string blob;

if (!readFileToString(blob_file, &blob)) return false;

Keystore keystore;

if (!keystore) return false;

LOG(DEBUG) << "Deleting key " << blob_file << " from Keystore";

if (!keystore.deleteKey(blob)) return false;

return true;

}

bool runSecdiscardSingle(const std::string& file) {

if (ForkExecvp(std::vector<std::string>{kSecdiscardPath, "--", file}) != 0) {

LOG(ERROR) << "secdiscard failed";

return false;

}

return true;

}

static bool recursiveDeleteKey(const std::string& dir) {

if (ForkExecvp(std::vector<std::string>{kRmPath, "-rf", dir}) != 0) {

LOG(ERROR) << "recursive delete failed";

return false;

}

return true;

}

bool destroyKey(const std::string& dir) {

bool success = true;

CancelPendingKeyCommit(dir);

auto secdiscard_cmd = std::vector<std::string>{

kSecdiscardPath,

"--",

dir + "/" + kFn_encrypted_key,

};

auto secdiscardable = dir + "/" + kFn_secdiscardable;

if (pathExists(secdiscardable)) {

secdiscard_cmd.push_back(secdiscardable);

}

// Try each thing, even if previous things failed.

for (auto& fn : {kFn_keymaster_key_blob, kFn_keymaster_key_blob_upgraded}) {

auto blob_file = dir + "/" + fn;

if (pathExists(blob_file)) {

success &= DeleteKeystoreKey(blob_file);

secdiscard_cmd.push_back(blob_file);

}

}

if (ForkExecvp(secdiscard_cmd) != 0) {

LOG(ERROR) << "secdiscard failed";

success = false;

}

success &= recursiveDeleteKey(dir);

return success;

}

bool setKeyStorageBindingSeed(const std::vector<uint8_t>& seed) {

const std::lock_guard<std::mutex> scope_lock(storage_binding_info.guard);

switch (storage_binding_info.state) {

case StorageBindingInfo::State::UNINITIALIZED:

storage_binding_info.state = StorageBindingInfo::State::IN_USE;

storage_binding_info.seed = seed;

android::base::SetProperty("vold.storage_seed_bound", "1");

return true;

case StorageBindingInfo::State::IN_USE:

LOG(ERROR) << "key storage binding seed already set";

return false;

case StorageBindingInfo::State::NOT_USED:

LOG(ERROR) << "key storage already in use without binding";

return false;

}

return false;

}

} // namespace vold

} // namespace android