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PL286/system/security/keystore/key_store_service.cpp

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/*
* 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.
*/
#define LOG_TAG "keystore"
#include "key_store_service.h"
#include <fcntl.h>
#include <sys/stat.h>
#include <algorithm>
#include <sstream>
#include <binder/IInterface.h>
#include <binder/IPCThreadState.h>
#include <binder/IPermissionController.h>
#include <binder/IServiceManager.h>
#include <private/android_filesystem_config.h>
#include <android/hardware/keymaster/3.0/IHwKeymasterDevice.h>
#include "defaults.h"
#include "keystore_attestation_id.h"
#include "keystore_keymaster_enforcement.h"
#include "keystore_utils.h"
#include <keystore/keystore_hidl_support.h>
namespace keystore {
using namespace android;
namespace {
constexpr size_t kMaxOperations = 15;
constexpr double kIdRotationPeriod = 30 * 24 * 60 * 60; /* Thirty days, in seconds */
const char* kTimestampFilePath = "timestamp";
struct BIGNUM_Delete {
void operator()(BIGNUM* p) const { BN_free(p); }
};
typedef std::unique_ptr<BIGNUM, BIGNUM_Delete> Unique_BIGNUM;
bool containsTag(const hidl_vec<KeyParameter>& params, Tag tag) {
return params.end() != std::find_if(params.begin(), params.end(),
[&](auto& param) { return param.tag == tag; });
}
bool isAuthenticationBound(const hidl_vec<KeyParameter>& params) {
return !containsTag(params, Tag::NO_AUTH_REQUIRED);
}
std::pair<KeyStoreServiceReturnCode, bool> hadFactoryResetSinceIdRotation() {
struct stat sbuf;
if (stat(kTimestampFilePath, &sbuf) == 0) {
double diff_secs = difftime(time(NULL), sbuf.st_ctime);
return {ResponseCode::NO_ERROR, diff_secs < kIdRotationPeriod};
}
if (errno != ENOENT) {
ALOGE("Failed to stat \"timestamp\" file, with error %d", errno);
return {ResponseCode::SYSTEM_ERROR, false /* don't care */};
}
int fd = creat(kTimestampFilePath, 0600);
if (fd < 0) {
ALOGE("Couldn't create \"timestamp\" file, with error %d", errno);
return {ResponseCode::SYSTEM_ERROR, false /* don't care */};
}
if (close(fd)) {
ALOGE("Couldn't close \"timestamp\" file, with error %d", errno);
return {ResponseCode::SYSTEM_ERROR, false /* don't care */};
}
return {ResponseCode::NO_ERROR, true};
}
constexpr size_t KEY_ATTESTATION_APPLICATION_ID_MAX_SIZE = 1024;
KeyStoreServiceReturnCode updateParamsForAttestation(uid_t callingUid, AuthorizationSet* params) {
KeyStoreServiceReturnCode responseCode;
bool factoryResetSinceIdRotation;
std::tie(responseCode, factoryResetSinceIdRotation) = hadFactoryResetSinceIdRotation();
if (!responseCode.isOk()) return responseCode;
if (factoryResetSinceIdRotation) params->push_back(TAG_RESET_SINCE_ID_ROTATION);
auto asn1_attestation_id_result = security::gather_attestation_application_id(callingUid);
if (!asn1_attestation_id_result.isOk()) {
ALOGE("failed to gather attestation_id");
return ErrorCode::ATTESTATION_APPLICATION_ID_MISSING;
}
std::vector<uint8_t>& asn1_attestation_id = asn1_attestation_id_result;
/*
* The attestation application ID cannot be longer than
* KEY_ATTESTATION_APPLICATION_ID_MAX_SIZE, so we truncate if too long.
*/
if (asn1_attestation_id.size() > KEY_ATTESTATION_APPLICATION_ID_MAX_SIZE) {
asn1_attestation_id.resize(KEY_ATTESTATION_APPLICATION_ID_MAX_SIZE);
}
params->push_back(TAG_ATTESTATION_APPLICATION_ID, asn1_attestation_id);
return ResponseCode::NO_ERROR;
}
} // anonymous namespace
void KeyStoreService::binderDied(const wp<IBinder>& who) {
auto operations = mOperationMap.getOperationsForToken(who.unsafe_get());
for (const auto& token : operations) {
abort(token);
}
}
KeyStoreServiceReturnCode KeyStoreService::getState(int32_t userId) {
if (!checkBinderPermission(P_GET_STATE)) {
return ResponseCode::PERMISSION_DENIED;
}
return ResponseCode(mKeyStore->getState(userId));
}
KeyStoreServiceReturnCode KeyStoreService::get(const String16& name, int32_t uid,
hidl_vec<uint8_t>* item) {
uid_t targetUid = getEffectiveUid(uid);
if (!checkBinderPermission(P_GET, targetUid)) {
return ResponseCode::PERMISSION_DENIED;
}
String8 name8(name);
Blob keyBlob;
KeyStoreServiceReturnCode rc =
mKeyStore->getKeyForName(&keyBlob, name8, targetUid, TYPE_GENERIC);
if (!rc.isOk()) {
if (item) *item = hidl_vec<uint8_t>();
return rc;
}
// Do not replace this with "if (item) *item = blob2hidlVec(keyBlob)"!
// blob2hidlVec creates a hidl_vec<uint8_t> that references, but not owns, the data in keyBlob
// the subsequent assignment (*item = resultBlob) makes a deep copy, so that *item will own the
// corresponding resources.
auto resultBlob = blob2hidlVec(keyBlob);
if (item) {
*item = resultBlob;
}
return ResponseCode::NO_ERROR;
}
KeyStoreServiceReturnCode KeyStoreService::insert(const String16& name,
const hidl_vec<uint8_t>& item, int targetUid,
int32_t flags) {
targetUid = getEffectiveUid(targetUid);
auto result =
checkBinderPermissionAndKeystoreState(P_INSERT, targetUid, flags & KEYSTORE_FLAG_ENCRYPTED);
if (!result.isOk()) {
return result;
}
String8 name8(name);
String8 filename(mKeyStore->getKeyNameForUidWithDir(name8, targetUid, ::TYPE_GENERIC));
Blob keyBlob(&item[0], item.size(), NULL, 0, ::TYPE_GENERIC);
keyBlob.setEncrypted(flags & KEYSTORE_FLAG_ENCRYPTED);
return mKeyStore->put(filename.string(), &keyBlob, get_user_id(targetUid));
}
KeyStoreServiceReturnCode KeyStoreService::del(const String16& name, int targetUid) {
targetUid = getEffectiveUid(targetUid);
if (!checkBinderPermission(P_DELETE, targetUid)) {
return ResponseCode::PERMISSION_DENIED;
}
String8 name8(name);
ALOGI("del %s %d", name8.string(), targetUid);
auto filename = mKeyStore->getBlobFileNameIfExists(name8, targetUid, ::TYPE_ANY);
if (!filename.isOk()) return ResponseCode::KEY_NOT_FOUND;
ResponseCode result = mKeyStore->del(filename.value().string(), ::TYPE_ANY,
get_user_id(targetUid));
if (result != ResponseCode::NO_ERROR) {
return result;
}
filename = mKeyStore->getBlobFileNameIfExists(name8, targetUid, ::TYPE_KEY_CHARACTERISTICS);
if (filename.isOk()) {
return mKeyStore->del(filename.value().string(), ::TYPE_KEY_CHARACTERISTICS,
get_user_id(targetUid));
}
return ResponseCode::NO_ERROR;
}
KeyStoreServiceReturnCode KeyStoreService::exist(const String16& name, int targetUid) {
targetUid = getEffectiveUid(targetUid);
if (!checkBinderPermission(P_EXIST, targetUid)) {
return ResponseCode::PERMISSION_DENIED;
}
auto filename = mKeyStore->getBlobFileNameIfExists(String8(name), targetUid, ::TYPE_ANY);
return filename.isOk() ? ResponseCode::NO_ERROR : ResponseCode::KEY_NOT_FOUND;
}
KeyStoreServiceReturnCode KeyStoreService::list(const String16& prefix, int targetUid,
Vector<String16>* matches) {
targetUid = getEffectiveUid(targetUid);
if (!checkBinderPermission(P_LIST, targetUid)) {
return ResponseCode::PERMISSION_DENIED;
}
const String8 prefix8(prefix);
String8 filename(mKeyStore->getKeyNameForUid(prefix8, targetUid, TYPE_ANY));
if (mKeyStore->list(filename, matches, get_user_id(targetUid)) != ResponseCode::NO_ERROR) {
return ResponseCode::SYSTEM_ERROR;
}
return ResponseCode::NO_ERROR;
}
KeyStoreServiceReturnCode KeyStoreService::reset() {
if (!checkBinderPermission(P_RESET)) {
return ResponseCode::PERMISSION_DENIED;
}
uid_t callingUid = IPCThreadState::self()->getCallingUid();
mKeyStore->resetUser(get_user_id(callingUid), false);
return ResponseCode::NO_ERROR;
}
KeyStoreServiceReturnCode KeyStoreService::onUserPasswordChanged(int32_t userId,
const String16& password) {
if (!checkBinderPermission(P_PASSWORD)) {
return ResponseCode::PERMISSION_DENIED;
}
const String8 password8(password);
// Flush the auth token table to prevent stale tokens from sticking
// around.
mAuthTokenTable.Clear();
if (password.size() == 0) {
ALOGI("Secure lockscreen for user %d removed, deleting encrypted entries", userId);
mKeyStore->resetUser(userId, true);
return ResponseCode::NO_ERROR;
} else {
switch (mKeyStore->getState(userId)) {
case ::STATE_UNINITIALIZED: {
// generate master key, encrypt with password, write to file,
// initialize mMasterKey*.
return mKeyStore->initializeUser(password8, userId);
}
case ::STATE_NO_ERROR: {
// rewrite master key with new password.
return mKeyStore->writeMasterKey(password8, userId);
}
case ::STATE_LOCKED: {
ALOGE("Changing user %d's password while locked, clearing old encryption", userId);
mKeyStore->resetUser(userId, true);
return mKeyStore->initializeUser(password8, userId);
}
}
return ResponseCode::SYSTEM_ERROR;
}
}
KeyStoreServiceReturnCode KeyStoreService::onUserAdded(int32_t userId, int32_t parentId) {
if (!checkBinderPermission(P_USER_CHANGED)) {
return ResponseCode::PERMISSION_DENIED;
}
// Sanity check that the new user has an empty keystore.
if (!mKeyStore->isEmpty(userId)) {
ALOGW("New user %d's keystore not empty. Clearing old entries.", userId);
}
// Unconditionally clear the keystore, just to be safe.
mKeyStore->resetUser(userId, false);
if (parentId != -1) {
// This profile must share the same master key password as the parent profile. Because the
// password of the parent profile is not known here, the best we can do is copy the parent's
// master key and master key file. This makes this profile use the same master key as the
// parent profile, forever.
return mKeyStore->copyMasterKey(parentId, userId);
} else {
return ResponseCode::NO_ERROR;
}
}
KeyStoreServiceReturnCode KeyStoreService::onUserRemoved(int32_t userId) {
if (!checkBinderPermission(P_USER_CHANGED)) {
return ResponseCode::PERMISSION_DENIED;
}
mKeyStore->resetUser(userId, false);
return ResponseCode::NO_ERROR;
}
KeyStoreServiceReturnCode KeyStoreService::lock(int32_t userId) {
if (!checkBinderPermission(P_LOCK)) {
return ResponseCode::PERMISSION_DENIED;
}
State state = mKeyStore->getState(userId);
if (state != ::STATE_NO_ERROR) {
ALOGD("calling lock in state: %d", state);
return ResponseCode(state);
}
mKeyStore->lock(userId);
return ResponseCode::NO_ERROR;
}
KeyStoreServiceReturnCode KeyStoreService::unlock(int32_t userId, const String16& pw) {
if (!checkBinderPermission(P_UNLOCK)) {
return ResponseCode::PERMISSION_DENIED;
}
State state = mKeyStore->getState(userId);
if (state != ::STATE_LOCKED) {
switch (state) {
case ::STATE_NO_ERROR:
ALOGI("calling unlock when already unlocked, ignoring.");
break;
case ::STATE_UNINITIALIZED:
ALOGE("unlock called on uninitialized keystore.");
break;
default:
ALOGE("unlock called on keystore in unknown state: %d", state);
break;
}
return ResponseCode(state);
}
const String8 password8(pw);
// read master key, decrypt with password, initialize mMasterKey*.
return mKeyStore->readMasterKey(password8, userId);
}
bool KeyStoreService::isEmpty(int32_t userId) {
if (!checkBinderPermission(P_IS_EMPTY)) {
return false;
}
return mKeyStore->isEmpty(userId);
}
KeyStoreServiceReturnCode KeyStoreService::generate(const String16& name, int32_t targetUid,
int32_t keyType, int32_t keySize, int32_t flags,
Vector<sp<KeystoreArg>>* args) {
targetUid = getEffectiveUid(targetUid);
auto result =
checkBinderPermissionAndKeystoreState(P_INSERT, targetUid, flags & KEYSTORE_FLAG_ENCRYPTED);
if (!result.isOk()) {
return result;
}
keystore::AuthorizationSet params;
add_legacy_key_authorizations(keyType, &params);
switch (keyType) {
case EVP_PKEY_EC: {
params.push_back(TAG_ALGORITHM, Algorithm::EC);
if (keySize == -1) {
keySize = EC_DEFAULT_KEY_SIZE;
} else if (keySize < EC_MIN_KEY_SIZE || keySize > EC_MAX_KEY_SIZE) {
ALOGI("invalid key size %d", keySize);
return ResponseCode::SYSTEM_ERROR;
}
params.push_back(TAG_KEY_SIZE, keySize);
break;
}
case EVP_PKEY_RSA: {
params.push_back(TAG_ALGORITHM, Algorithm::RSA);
if (keySize == -1) {
keySize = RSA_DEFAULT_KEY_SIZE;
} else if (keySize < RSA_MIN_KEY_SIZE || keySize > RSA_MAX_KEY_SIZE) {
ALOGI("invalid key size %d", keySize);
return ResponseCode::SYSTEM_ERROR;
}
params.push_back(TAG_KEY_SIZE, keySize);
unsigned long exponent = RSA_DEFAULT_EXPONENT;
if (args->size() > 1) {
ALOGI("invalid number of arguments: %zu", args->size());
return ResponseCode::SYSTEM_ERROR;
} else if (args->size() == 1) {
const sp<KeystoreArg>& expArg = args->itemAt(0);
if (expArg != NULL) {
Unique_BIGNUM pubExpBn(BN_bin2bn(
reinterpret_cast<const unsigned char*>(expArg->data()), expArg->size(), NULL));
if (pubExpBn.get() == NULL) {
ALOGI("Could not convert public exponent to BN");
return ResponseCode::SYSTEM_ERROR;
}
exponent = BN_get_word(pubExpBn.get());
if (exponent == 0xFFFFFFFFL) {
ALOGW("cannot represent public exponent as a long value");
return ResponseCode::SYSTEM_ERROR;
}
} else {
ALOGW("public exponent not read");
return ResponseCode::SYSTEM_ERROR;
}
}
params.push_back(TAG_RSA_PUBLIC_EXPONENT, exponent);
break;
}
default: {
ALOGW("Unsupported key type %d", keyType);
return ResponseCode::SYSTEM_ERROR;
}
}
auto rc = generateKey(name, params.hidl_data(), hidl_vec<uint8_t>(), targetUid, flags,
/*outCharacteristics*/ NULL);
if (!rc.isOk()) {
ALOGW("generate failed: %d", int32_t(rc));
}
return translateResultToLegacyResult(rc);
}
KeyStoreServiceReturnCode KeyStoreService::import(const String16& name,
const hidl_vec<uint8_t>& data, int targetUid,
int32_t flags) {
const uint8_t* ptr = &data[0];
Unique_PKCS8_PRIV_KEY_INFO pkcs8(d2i_PKCS8_PRIV_KEY_INFO(NULL, &ptr, data.size()));
if (!pkcs8.get()) {
return ResponseCode::SYSTEM_ERROR;
}
Unique_EVP_PKEY pkey(EVP_PKCS82PKEY(pkcs8.get()));
if (!pkey.get()) {
return ResponseCode::SYSTEM_ERROR;
}
int type = EVP_PKEY_type(pkey->type);
AuthorizationSet params;
add_legacy_key_authorizations(type, &params);
switch (type) {
case EVP_PKEY_RSA:
params.push_back(TAG_ALGORITHM, Algorithm::RSA);
break;
case EVP_PKEY_EC:
params.push_back(TAG_ALGORITHM, Algorithm::EC);
break;
default:
ALOGW("Unsupported key type %d", type);
return ResponseCode::SYSTEM_ERROR;
}
auto rc = importKey(name, params.hidl_data(), KeyFormat::PKCS8, data, targetUid, flags,
/*outCharacteristics*/ NULL);
if (!rc.isOk()) {
ALOGW("importKey failed: %d", int32_t(rc));
}
return translateResultToLegacyResult(rc);
}
KeyStoreServiceReturnCode KeyStoreService::sign(const String16& name, const hidl_vec<uint8_t>& data,
hidl_vec<uint8_t>* out) {
if (!checkBinderPermission(P_SIGN)) {
return ResponseCode::PERMISSION_DENIED;
}
return doLegacySignVerify(name, data, out, hidl_vec<uint8_t>(), KeyPurpose::SIGN);
}
KeyStoreServiceReturnCode KeyStoreService::verify(const String16& name,
const hidl_vec<uint8_t>& data,
const hidl_vec<uint8_t>& signature) {
if (!checkBinderPermission(P_VERIFY)) {
return ResponseCode::PERMISSION_DENIED;
}
return doLegacySignVerify(name, data, nullptr, signature, KeyPurpose::VERIFY);
}
/*
* TODO: The abstraction between things stored in hardware and regular blobs
* of data stored on the filesystem should be moved down to keystore itself.
* Unfortunately the Java code that calls this has naming conventions that it
* knows about. Ideally keystore shouldn't be used to store random blobs of
* data.
*
* Until that happens, it's necessary to have a separate "get_pubkey" and
* "del_key" since the Java code doesn't really communicate what it's
* intentions are.
*/
KeyStoreServiceReturnCode KeyStoreService::get_pubkey(const String16& name,
hidl_vec<uint8_t>* pubKey) {
ExportResult result;
exportKey(name, KeyFormat::X509, hidl_vec<uint8_t>(), hidl_vec<uint8_t>(), UID_SELF, &result);
if (!result.resultCode.isOk()) {
ALOGW("export failed: %d", int32_t(result.resultCode));
return translateResultToLegacyResult(result.resultCode);
}
if (pubKey) *pubKey = std::move(result.exportData);
return ResponseCode::NO_ERROR;
}
String16 KeyStoreService::grant(const String16& name, int32_t granteeUid) {
uid_t callingUid = IPCThreadState::self()->getCallingUid();
auto result = checkBinderPermissionAndKeystoreState(P_GRANT);
if (!result.isOk()) {
return String16();
}
String8 name8(name);
String8 filename(mKeyStore->getKeyNameForUidWithDir(name8, callingUid, ::TYPE_ANY));
if (access(filename.string(), R_OK) == -1) {
return String16();
}
return String16(mKeyStore->addGrant(String8(name).string(), callingUid, granteeUid).c_str());
}
KeyStoreServiceReturnCode KeyStoreService::ungrant(const String16& name, int32_t granteeUid) {
uid_t callingUid = IPCThreadState::self()->getCallingUid();
auto result = checkBinderPermissionAndKeystoreState(P_GRANT);
if (!result.isOk()) {
return result;
}
String8 name8(name);
String8 filename(mKeyStore->getKeyNameForUidWithDir(name8, callingUid, ::TYPE_ANY));
if (access(filename.string(), R_OK) == -1) {
return (errno != ENOENT) ? ResponseCode::SYSTEM_ERROR : ResponseCode::KEY_NOT_FOUND;
}
return mKeyStore->removeGrant(name8, callingUid, granteeUid) ? ResponseCode::NO_ERROR
: ResponseCode::KEY_NOT_FOUND;
}
int64_t KeyStoreService::getmtime(const String16& name, int32_t uid) {
uid_t targetUid = getEffectiveUid(uid);
if (!checkBinderPermission(P_GET, targetUid)) {
ALOGW("permission denied for %d: getmtime", targetUid);
return -1L;
}
auto filename = mKeyStore->getBlobFileNameIfExists(String8(name), targetUid, ::TYPE_ANY);
if (!filename.isOk()) {
ALOGW("could not access %s for getmtime", filename.value().string());
return -1L;
}
int fd = TEMP_FAILURE_RETRY(open(filename.value().string(), O_NOFOLLOW, O_RDONLY));
if (fd < 0) {
ALOGW("could not open %s for getmtime", filename.value().string());
return -1L;
}
struct stat s;
int ret = fstat(fd, &s);
close(fd);
if (ret == -1) {
ALOGW("could not stat %s for getmtime", filename.value().string());
return -1L;
}
return static_cast<int64_t>(s.st_mtime);
}
// TODO(tuckeris): This is dead code, remove it. Don't bother copying over key characteristics here
KeyStoreServiceReturnCode KeyStoreService::duplicate(const String16& srcKey, int32_t srcUid,
const String16& destKey, int32_t destUid) {
uid_t callingUid = IPCThreadState::self()->getCallingUid();
pid_t spid = IPCThreadState::self()->getCallingPid();
if (!has_permission(callingUid, P_DUPLICATE, spid)) {
ALOGW("permission denied for %d: duplicate", callingUid);
return ResponseCode::PERMISSION_DENIED;
}
State state = mKeyStore->getState(get_user_id(callingUid));
if (!isKeystoreUnlocked(state)) {
ALOGD("calling duplicate in state: %d", state);
return ResponseCode(state);
}
if (srcUid == -1 || static_cast<uid_t>(srcUid) == callingUid) {
srcUid = callingUid;
} else if (!is_granted_to(callingUid, srcUid)) {
ALOGD("migrate not granted from source: %d -> %d", callingUid, srcUid);
return ResponseCode::PERMISSION_DENIED;
}
if (destUid == -1) {
destUid = callingUid;
}
if (srcUid != destUid) {
if (static_cast<uid_t>(srcUid) != callingUid) {
ALOGD("can only duplicate from caller to other or to same uid: "
"calling=%d, srcUid=%d, destUid=%d",
callingUid, srcUid, destUid);
return ResponseCode::PERMISSION_DENIED;
}
if (!is_granted_to(callingUid, destUid)) {
ALOGD("duplicate not granted to dest: %d -> %d", callingUid, destUid);
return ResponseCode::PERMISSION_DENIED;
}
}
String8 source8(srcKey);
String8 sourceFile(mKeyStore->getKeyNameForUidWithDir(source8, srcUid, ::TYPE_ANY));
String8 target8(destKey);
String8 targetFile(mKeyStore->getKeyNameForUidWithDir(target8, destUid, ::TYPE_ANY));
if (access(targetFile.string(), W_OK) != -1 || errno != ENOENT) {
ALOGD("destination already exists: %s", targetFile.string());
return ResponseCode::SYSTEM_ERROR;
}
Blob keyBlob;
ResponseCode responseCode =
mKeyStore->get(sourceFile.string(), &keyBlob, TYPE_ANY, get_user_id(srcUid));
if (responseCode != ResponseCode::NO_ERROR) {
return responseCode;
}
return mKeyStore->put(targetFile.string(), &keyBlob, get_user_id(destUid));
}
int32_t KeyStoreService::is_hardware_backed(const String16& keyType) {
return mKeyStore->isHardwareBacked(keyType) ? 1 : 0;
}
KeyStoreServiceReturnCode KeyStoreService::clear_uid(int64_t targetUid64) {
uid_t targetUid = getEffectiveUid(targetUid64);
if (!checkBinderPermissionSelfOrSystem(P_CLEAR_UID, targetUid)) {
return ResponseCode::PERMISSION_DENIED;
}
ALOGI("clear_uid %" PRId64, targetUid64);
mKeyStore->removeAllGrantsToUid(targetUid);
String8 prefix = String8::format("%u_", targetUid);
Vector<String16> aliases;
if (mKeyStore->list(prefix, &aliases, get_user_id(targetUid)) != ResponseCode::NO_ERROR) {
return ResponseCode::SYSTEM_ERROR;
}
for (uint32_t i = 0; i < aliases.size(); i++) {
String8 name8(aliases[i]);
String8 filename(mKeyStore->getKeyNameForUidWithDir(name8, targetUid, ::TYPE_ANY));
if (get_app_id(targetUid) == AID_SYSTEM) {
Blob keyBlob;
ResponseCode responseCode =
mKeyStore->get(filename.string(), &keyBlob, ::TYPE_ANY, get_user_id(targetUid));
if (responseCode == ResponseCode::NO_ERROR && keyBlob.isCriticalToDeviceEncryption()) {
// Do not clear keys critical to device encryption under system uid.
continue;
}
}
mKeyStore->del(filename.string(), ::TYPE_ANY, get_user_id(targetUid));
// del() will fail silently if no cached characteristics are present for this alias.
String8 chr_filename(
mKeyStore->getKeyNameForUidWithDir(name8, targetUid, ::TYPE_KEY_CHARACTERISTICS));
mKeyStore->del(chr_filename.string(), ::TYPE_KEY_CHARACTERISTICS, get_user_id(targetUid));
}
return ResponseCode::NO_ERROR;
}
KeyStoreServiceReturnCode KeyStoreService::addRngEntropy(const hidl_vec<uint8_t>& entropy) {
const auto& device = mKeyStore->getDevice();
return KS_HANDLE_HIDL_ERROR(device->addRngEntropy(entropy));
}
KeyStoreServiceReturnCode KeyStoreService::generateKey(const String16& name,
const hidl_vec<KeyParameter>& params,
const hidl_vec<uint8_t>& entropy, int uid,
int flags,
KeyCharacteristics* outCharacteristics) {
// TODO(jbires): remove this getCallingUid call upon implementation of b/25646100
uid_t originalUid = IPCThreadState::self()->getCallingUid();
uid = getEffectiveUid(uid);
KeyStoreServiceReturnCode rc =
checkBinderPermissionAndKeystoreState(P_INSERT, uid, flags & KEYSTORE_FLAG_ENCRYPTED);
if (!rc.isOk()) {
return rc;
}
if ((flags & KEYSTORE_FLAG_CRITICAL_TO_DEVICE_ENCRYPTION) && get_app_id(uid) != AID_SYSTEM) {
ALOGE("Non-system uid %d cannot set FLAG_CRITICAL_TO_DEVICE_ENCRYPTION", uid);
return ResponseCode::PERMISSION_DENIED;
}
if (containsTag(params, Tag::INCLUDE_UNIQUE_ID)) {
if (!checkBinderPermission(P_GEN_UNIQUE_ID) ||
originalUid != IPCThreadState::self()->getCallingUid()) {
return ResponseCode::PERMISSION_DENIED;
}
}
bool usingFallback = false;
auto& dev = mKeyStore->getDevice();
AuthorizationSet keyCharacteristics = params;
// TODO: Seed from Linux RNG before this.
rc = addRngEntropy(entropy);
if (!rc.isOk()) {
return rc;
}
KeyStoreServiceReturnCode error;
auto hidl_cb = [&](ErrorCode ret, const hidl_vec<uint8_t>& hidlKeyBlob,
const KeyCharacteristics& keyCharacteristics) {
error = ret;
if (!error.isOk()) {
return;
}
if (outCharacteristics) *outCharacteristics = keyCharacteristics;
// Write the key
String8 name8(name);
String8 filename(mKeyStore->getKeyNameForUidWithDir(name8, uid, ::TYPE_KEYMASTER_10));
Blob keyBlob(&hidlKeyBlob[0], hidlKeyBlob.size(), NULL, 0, ::TYPE_KEYMASTER_10);
keyBlob.setFallback(usingFallback);
keyBlob.setCriticalToDeviceEncryption(flags & KEYSTORE_FLAG_CRITICAL_TO_DEVICE_ENCRYPTION);
if (isAuthenticationBound(params) && !keyBlob.isCriticalToDeviceEncryption()) {
keyBlob.setSuperEncrypted(true);
}
keyBlob.setEncrypted(flags & KEYSTORE_FLAG_ENCRYPTED);
error = mKeyStore->put(filename.string(), &keyBlob, get_user_id(uid));
};
rc = KS_HANDLE_HIDL_ERROR(dev->generateKey(params, hidl_cb));
if (!rc.isOk()) {
return rc;
}
if (!error.isOk()) {
ALOGE("Failed to generate key -> falling back to software keymaster");
usingFallback = true;
auto fallback = mKeyStore->getFallbackDevice();
if (!fallback.isOk()) {
return error;
}
rc = KS_HANDLE_HIDL_ERROR(fallback.value()->generateKey(params, hidl_cb));
if (!rc.isOk()) {
return rc;
}
if (!error.isOk()) {
return error;
}
}
// Write the characteristics:
String8 name8(name);
String8 cFilename(mKeyStore->getKeyNameForUidWithDir(name8, uid, ::TYPE_KEY_CHARACTERISTICS));
std::stringstream kc_stream;
keyCharacteristics.Serialize(&kc_stream);
if (kc_stream.bad()) {
return ResponseCode::SYSTEM_ERROR;
}
auto kc_buf = kc_stream.str();
Blob charBlob(reinterpret_cast<const uint8_t*>(kc_buf.data()), kc_buf.size(), NULL, 0,
::TYPE_KEY_CHARACTERISTICS);
charBlob.setFallback(usingFallback);
charBlob.setEncrypted(flags & KEYSTORE_FLAG_ENCRYPTED);
return mKeyStore->put(cFilename.string(), &charBlob, get_user_id(uid));
}
KeyStoreServiceReturnCode
KeyStoreService::getKeyCharacteristics(const String16& name, const hidl_vec<uint8_t>& clientId,
const hidl_vec<uint8_t>& appData, int32_t uid,
KeyCharacteristics* outCharacteristics) {
if (!outCharacteristics) {
return ErrorCode::UNEXPECTED_NULL_POINTER;
}
uid_t targetUid = getEffectiveUid(uid);
uid_t callingUid = IPCThreadState::self()->getCallingUid();
if (!is_granted_to(callingUid, targetUid)) {
ALOGW("uid %d not permitted to act for uid %d in getKeyCharacteristics", callingUid,
targetUid);
return ResponseCode::PERMISSION_DENIED;
}
Blob keyBlob;
String8 name8(name);
KeyStoreServiceReturnCode rc =
mKeyStore->getKeyForName(&keyBlob, name8, targetUid, TYPE_KEYMASTER_10);
if (rc == ResponseCode::UNINITIALIZED) {
/*
* If we fail reading the blob because the master key is missing we try to retrieve the
* key characteristics from the characteristics file. This happens when auth-bound
* keys are used after a screen lock has been removed by the user.
*/
rc = mKeyStore->getKeyForName(&keyBlob, name8, targetUid, TYPE_KEY_CHARACTERISTICS);
if (!rc.isOk()) {
return rc;
}
AuthorizationSet keyCharacteristics;
// TODO write one shot stream buffer to avoid copying (twice here)
std::string charBuffer(reinterpret_cast<const char*>(keyBlob.getValue()),
keyBlob.getLength());
std::stringstream charStream(charBuffer);
keyCharacteristics.Deserialize(&charStream);
outCharacteristics->softwareEnforced = keyCharacteristics.hidl_data();
return rc;
} else if (!rc.isOk()) {
return rc;
}
auto hidlKeyBlob = blob2hidlVec(keyBlob);
auto& dev = mKeyStore->getDevice(keyBlob);
KeyStoreServiceReturnCode error;
auto hidlCb = [&](ErrorCode ret, const KeyCharacteristics& keyCharacteristics) {
error = ret;
if (!error.isOk()) {
return;
}
*outCharacteristics = keyCharacteristics;
};
rc = KS_HANDLE_HIDL_ERROR(dev->getKeyCharacteristics(hidlKeyBlob, clientId, appData, hidlCb));
if (!rc.isOk()) {
return rc;
}
if (error == ErrorCode::KEY_REQUIRES_UPGRADE) {
AuthorizationSet upgradeParams;
if (clientId.size()) {
upgradeParams.push_back(TAG_APPLICATION_ID, clientId);
}
if (appData.size()) {
upgradeParams.push_back(TAG_APPLICATION_DATA, appData);
}
rc = upgradeKeyBlob(name, targetUid, upgradeParams, &keyBlob);
if (!rc.isOk()) {
return rc;
}
auto upgradedHidlKeyBlob = blob2hidlVec(keyBlob);
rc = KS_HANDLE_HIDL_ERROR(
dev->getKeyCharacteristics(upgradedHidlKeyBlob, clientId, appData, hidlCb));
if (!rc.isOk()) {
return rc;
}
// Note that, on success, "error" will have been updated by the hidlCB callback.
// So it is fine to return "error" below.
}
return error;
}
KeyStoreServiceReturnCode
KeyStoreService::importKey(const String16& name, const hidl_vec<KeyParameter>& params,
KeyFormat format, const hidl_vec<uint8_t>& keyData, int uid, int flags,
KeyCharacteristics* outCharacteristics) {
uid = getEffectiveUid(uid);
KeyStoreServiceReturnCode rc =
checkBinderPermissionAndKeystoreState(P_INSERT, uid, flags & KEYSTORE_FLAG_ENCRYPTED);
if (!rc.isOk()) {
return rc;
}
if ((flags & KEYSTORE_FLAG_CRITICAL_TO_DEVICE_ENCRYPTION) && get_app_id(uid) != AID_SYSTEM) {
ALOGE("Non-system uid %d cannot set FLAG_CRITICAL_TO_DEVICE_ENCRYPTION", uid);
return ResponseCode::PERMISSION_DENIED;
}
bool usingFallback = false;
auto& dev = mKeyStore->getDevice();
String8 name8(name);
KeyStoreServiceReturnCode error;
auto hidlCb = [&](ErrorCode ret, const hidl_vec<uint8_t>& keyBlob,
const KeyCharacteristics& keyCharacteristics) {
error = ret;
if (!error.isOk()) {
return;
}
if (outCharacteristics) *outCharacteristics = keyCharacteristics;
// Write the key:
String8 filename(mKeyStore->getKeyNameForUidWithDir(name8, uid, ::TYPE_KEYMASTER_10));
Blob ksBlob(&keyBlob[0], keyBlob.size(), NULL, 0, ::TYPE_KEYMASTER_10);
ksBlob.setFallback(usingFallback);
ksBlob.setCriticalToDeviceEncryption(flags & KEYSTORE_FLAG_CRITICAL_TO_DEVICE_ENCRYPTION);
if (isAuthenticationBound(params) && !ksBlob.isCriticalToDeviceEncryption()) {
ksBlob.setSuperEncrypted(true);
}
ksBlob.setEncrypted(flags & KEYSTORE_FLAG_ENCRYPTED);
error = mKeyStore->put(filename.string(), &ksBlob, get_user_id(uid));
};
rc = KS_HANDLE_HIDL_ERROR(dev->importKey(params, format, keyData, hidlCb));
// possible hidl error
if (!rc.isOk()) {
return rc;
}
// now check error from callback
if (!error.isOk()) {
ALOGE("Failed to import key -> falling back to software keymaster");
usingFallback = true;
auto fallback = mKeyStore->getFallbackDevice();
if (!fallback.isOk()) {
return error;
}
rc = KS_HANDLE_HIDL_ERROR(fallback.value()->importKey(params, format, keyData, hidlCb));
// possible hidl error
if (!rc.isOk()) {
return rc;
}
// now check error from callback
if (!error.isOk()) {
return error;
}
}
// Write the characteristics:
String8 cFilename(mKeyStore->getKeyNameForUidWithDir(name8, uid, ::TYPE_KEY_CHARACTERISTICS));
AuthorizationSet opParams = params;
std::stringstream kcStream;
opParams.Serialize(&kcStream);
if (kcStream.bad()) return ResponseCode::SYSTEM_ERROR;
auto kcBuf = kcStream.str();
Blob charBlob(reinterpret_cast<const uint8_t*>(kcBuf.data()), kcBuf.size(), NULL, 0,
::TYPE_KEY_CHARACTERISTICS);
charBlob.setFallback(usingFallback);
charBlob.setEncrypted(flags & KEYSTORE_FLAG_ENCRYPTED);
return mKeyStore->put(cFilename.string(), &charBlob, get_user_id(uid));
}
void KeyStoreService::exportKey(const String16& name, KeyFormat format,
const hidl_vec<uint8_t>& clientId, const hidl_vec<uint8_t>& appData,
int32_t uid, ExportResult* result) {
uid_t targetUid = getEffectiveUid(uid);
uid_t callingUid = IPCThreadState::self()->getCallingUid();
if (!is_granted_to(callingUid, targetUid)) {
ALOGW("uid %d not permitted to act for uid %d in exportKey", callingUid, targetUid);
result->resultCode = ResponseCode::PERMISSION_DENIED;
return;
}
Blob keyBlob;
String8 name8(name);
result->resultCode = mKeyStore->getKeyForName(&keyBlob, name8, targetUid, TYPE_KEYMASTER_10);
if (!result->resultCode.isOk()) {
return;
}
auto key = blob2hidlVec(keyBlob);
auto& dev = mKeyStore->getDevice(keyBlob);
auto hidlCb = [&](ErrorCode ret, const ::android::hardware::hidl_vec<uint8_t>& keyMaterial) {
result->resultCode = ret;
if (!result->resultCode.isOk()) {
return;
}
result->exportData = keyMaterial;
};
KeyStoreServiceReturnCode rc =
KS_HANDLE_HIDL_ERROR(dev->exportKey(format, key, clientId, appData, hidlCb));
// Overwrite result->resultCode only on HIDL error. Otherwise we want the result set in the
// callback hidlCb.
if (!rc.isOk()) {
result->resultCode = rc;
}
if (result->resultCode == ErrorCode::KEY_REQUIRES_UPGRADE) {
AuthorizationSet upgradeParams;
if (clientId.size()) {
upgradeParams.push_back(TAG_APPLICATION_ID, clientId);
}
if (appData.size()) {
upgradeParams.push_back(TAG_APPLICATION_DATA, appData);
}
result->resultCode = upgradeKeyBlob(name, targetUid, upgradeParams, &keyBlob);
if (!result->resultCode.isOk()) {
return;
}
auto upgradedHidlKeyBlob = blob2hidlVec(keyBlob);
result->resultCode = KS_HANDLE_HIDL_ERROR(
dev->exportKey(format, upgradedHidlKeyBlob, clientId, appData, hidlCb));
if (!result->resultCode.isOk()) {
return;
}
}
}
static inline void addAuthTokenToParams(AuthorizationSet* params, const HardwareAuthToken* token) {
if (token) {
params->push_back(TAG_AUTH_TOKEN, authToken2HidlVec(*token));
}
}
void KeyStoreService::begin(const sp<IBinder>& appToken, const String16& name, KeyPurpose purpose,
bool pruneable, const hidl_vec<KeyParameter>& params,
const hidl_vec<uint8_t>& entropy, int32_t uid,
OperationResult* result) {
uid_t callingUid = IPCThreadState::self()->getCallingUid();
uid_t targetUid = getEffectiveUid(uid);
if (!is_granted_to(callingUid, targetUid)) {
ALOGW("uid %d not permitted to act for uid %d in begin", callingUid, targetUid);
result->resultCode = ResponseCode::PERMISSION_DENIED;
return;
}
if (!pruneable && get_app_id(callingUid) != AID_SYSTEM) {
ALOGE("Non-system uid %d trying to start non-pruneable operation", callingUid);
result->resultCode = ResponseCode::PERMISSION_DENIED;
return;
}
if (!checkAllowedOperationParams(params)) {
result->resultCode = ErrorCode::INVALID_ARGUMENT;
return;
}
Blob keyBlob;
String8 name8(name);
result->resultCode = mKeyStore->getKeyForName(&keyBlob, name8, targetUid, TYPE_KEYMASTER_10);
if (result->resultCode == ResponseCode::LOCKED && keyBlob.isSuperEncrypted()) {
result->resultCode = ErrorCode::KEY_USER_NOT_AUTHENTICATED;
}
if (!result->resultCode.isOk()) {
return;
}
auto key = blob2hidlVec(keyBlob);
auto& dev = mKeyStore->getDevice(keyBlob);
AuthorizationSet opParams = params;
KeyCharacteristics characteristics;
result->resultCode = getOperationCharacteristics(key, &dev, opParams, &characteristics);
if (result->resultCode == ErrorCode::KEY_REQUIRES_UPGRADE) {
result->resultCode = upgradeKeyBlob(name, targetUid, opParams, &keyBlob);
if (!result->resultCode.isOk()) {
return;
}
key = blob2hidlVec(keyBlob);
result->resultCode = getOperationCharacteristics(key, &dev, opParams, &characteristics);
}
if (!result->resultCode.isOk()) {
return;
}
const HardwareAuthToken* authToken = NULL;
// Merge these characteristics with the ones cached when the key was generated or imported
Blob charBlob;
AuthorizationSet persistedCharacteristics;
result->resultCode =
mKeyStore->getKeyForName(&charBlob, name8, targetUid, TYPE_KEY_CHARACTERISTICS);
if (result->resultCode.isOk()) {
// TODO write one shot stream buffer to avoid copying (twice here)
std::string charBuffer(reinterpret_cast<const char*>(charBlob.getValue()),
charBlob.getLength());
std::stringstream charStream(charBuffer);
persistedCharacteristics.Deserialize(&charStream);
} else {
ALOGD("Unable to read cached characteristics for key");
}
// Replace the sw_enforced set with those persisted to disk, minus hw_enforced
AuthorizationSet softwareEnforced = characteristics.softwareEnforced;
AuthorizationSet teeEnforced = characteristics.teeEnforced;
persistedCharacteristics.Union(softwareEnforced);
persistedCharacteristics.Subtract(teeEnforced);
characteristics.softwareEnforced = persistedCharacteristics.hidl_data();
auto authResult = getAuthToken(characteristics, 0, purpose, &authToken,
/*failOnTokenMissing*/ false);
// If per-operation auth is needed we need to begin the operation and
// the client will need to authorize that operation before calling
// update. Any other auth issues stop here.
if (!authResult.isOk() && authResult != ResponseCode::OP_AUTH_NEEDED) {
result->resultCode = authResult;
return;
}
addAuthTokenToParams(&opParams, authToken);
// Add entropy to the device first.
if (entropy.size()) {
result->resultCode = addRngEntropy(entropy);
if (!result->resultCode.isOk()) {
return;
}
}
// Create a keyid for this key.
km_id_t keyid;
if (!enforcement_policy.CreateKeyId(key, &keyid)) {
ALOGE("Failed to create a key ID for authorization checking.");
result->resultCode = ErrorCode::UNKNOWN_ERROR;
return;
}
// Check that all key authorization policy requirements are met.
AuthorizationSet key_auths = characteristics.teeEnforced;
key_auths.append(&characteristics.softwareEnforced[0],
&characteristics.softwareEnforced[characteristics.softwareEnforced.size()]);
result->resultCode = enforcement_policy.AuthorizeOperation(
purpose, keyid, key_auths, opParams, 0 /* op_handle */, true /* is_begin_operation */);
if (!result->resultCode.isOk()) {
return;
}
// If there are more than kMaxOperations, abort the oldest operation that was started as
// pruneable.
while (mOperationMap.getOperationCount() >= kMaxOperations) {
ALOGD("Reached or exceeded concurrent operations limit");
if (!pruneOperation()) {
break;
}
}
auto hidlCb = [&](ErrorCode ret, const hidl_vec<KeyParameter>& outParams,
uint64_t operationHandle) {
result->resultCode = ret;
if (!result->resultCode.isOk()) {
return;
}
result->handle = operationHandle;
result->outParams = outParams;
};
ErrorCode rc = KS_HANDLE_HIDL_ERROR(dev->begin(purpose, key, opParams.hidl_data(), hidlCb));
if (rc != ErrorCode::OK) {
ALOGW("Got error %d from begin()", rc);
}
// If there are too many operations abort the oldest operation that was
// started as pruneable and try again.
while (rc == ErrorCode::TOO_MANY_OPERATIONS && mOperationMap.hasPruneableOperation()) {
ALOGW("Ran out of operation handles");
if (!pruneOperation()) {
break;
}
rc = KS_HANDLE_HIDL_ERROR(dev->begin(purpose, key, opParams.hidl_data(), hidlCb));
}
if (rc != ErrorCode::OK) {
result->resultCode = rc;
return;
}
// Note: The operation map takes possession of the contents of "characteristics".
// It is safe to use characteristics after the following line but it will be empty.
sp<IBinder> operationToken = mOperationMap.addOperation(
result->handle, keyid, purpose, dev, appToken, std::move(characteristics), pruneable);
assert(characteristics.teeEnforced.size() == 0);
assert(characteristics.softwareEnforced.size() == 0);
result->token = operationToken;
if (authToken) {
mOperationMap.setOperationAuthToken(operationToken, authToken);
}
// Return the authentication lookup result. If this is a per operation
// auth'd key then the resultCode will be ::OP_AUTH_NEEDED and the
// application should get an auth token using the handle before the
// first call to update, which will fail if keystore hasn't received the
// auth token.
if (result->resultCode == ErrorCode::OK) {
result->resultCode = authResult;
}
// Other result fields were set in the begin operation's callback.
}
void KeyStoreService::update(const sp<IBinder>& token, const hidl_vec<KeyParameter>& params,
const hidl_vec<uint8_t>& data, OperationResult* result) {
if (!checkAllowedOperationParams(params)) {
result->resultCode = ErrorCode::INVALID_ARGUMENT;
return;
}
km_device_t dev;
uint64_t handle;
KeyPurpose purpose;
km_id_t keyid;
const KeyCharacteristics* characteristics;
if (!mOperationMap.getOperation(token, &handle, &keyid, &purpose, &dev, &characteristics)) {
result->resultCode = ErrorCode::INVALID_OPERATION_HANDLE;
return;
}
AuthorizationSet opParams = params;
result->resultCode = addOperationAuthTokenIfNeeded(token, &opParams);
if (!result->resultCode.isOk()) {
return;
}
// Check that all key authorization policy requirements are met.
AuthorizationSet key_auths(characteristics->teeEnforced);
key_auths.append(&characteristics->softwareEnforced[0],
&characteristics->softwareEnforced[characteristics->softwareEnforced.size()]);
result->resultCode = enforcement_policy.AuthorizeOperation(
purpose, keyid, key_auths, opParams, handle, false /* is_begin_operation */);
if (!result->resultCode.isOk()) {
return;
}
auto hidlCb = [&](ErrorCode ret, uint32_t inputConsumed,
const hidl_vec<KeyParameter>& outParams, const hidl_vec<uint8_t>& output) {
result->resultCode = ret;
if (!result->resultCode.isOk()) {
return;
}
result->inputConsumed = inputConsumed;
result->outParams = outParams;
result->data = output;
};
KeyStoreServiceReturnCode rc = KS_HANDLE_HIDL_ERROR(dev->update(handle, opParams.hidl_data(),
data, hidlCb));
// just a reminder: on success result->resultCode was set in the callback. So we only overwrite
// it if there was a communication error indicated by the ErrorCode.
if (!rc.isOk()) {
result->resultCode = rc;
}
}
void KeyStoreService::finish(const sp<IBinder>& token, const hidl_vec<KeyParameter>& params,
const hidl_vec<uint8_t>& signature, const hidl_vec<uint8_t>& entropy,
OperationResult* result) {
if (!checkAllowedOperationParams(params)) {
result->resultCode = ErrorCode::INVALID_ARGUMENT;
return;
}
km_device_t dev;
uint64_t handle;
KeyPurpose purpose;
km_id_t keyid;
const KeyCharacteristics* characteristics;
if (!mOperationMap.getOperation(token, &handle, &keyid, &purpose, &dev, &characteristics)) {
result->resultCode = ErrorCode::INVALID_OPERATION_HANDLE;
return;
}
AuthorizationSet opParams = params;
result->resultCode = addOperationAuthTokenIfNeeded(token, &opParams);
if (!result->resultCode.isOk()) {
return;
}
if (entropy.size()) {
result->resultCode = addRngEntropy(entropy);
if (!result->resultCode.isOk()) {
return;
}
}
// Check that all key authorization policy requirements are met.
AuthorizationSet key_auths(characteristics->teeEnforced);
key_auths.append(&characteristics->softwareEnforced[0],
&characteristics->softwareEnforced[characteristics->softwareEnforced.size()]);
result->resultCode = enforcement_policy.AuthorizeOperation(
purpose, keyid, key_auths, opParams, handle, false /* is_begin_operation */);
if (!result->resultCode.isOk()) return;
auto hidlCb = [&](ErrorCode ret, const hidl_vec<KeyParameter>& outParams,
const hidl_vec<uint8_t>& output) {
result->resultCode = ret;
if (!result->resultCode.isOk()) {
return;
}
result->outParams = outParams;
result->data = output;
};
KeyStoreServiceReturnCode rc = KS_HANDLE_HIDL_ERROR(dev->finish(
handle, opParams.hidl_data(),
hidl_vec<uint8_t>() /* TODO(swillden): wire up input to finish() */, signature, hidlCb));
// Remove the operation regardless of the result
mOperationMap.removeOperation(token);
mAuthTokenTable.MarkCompleted(handle);
// just a reminder: on success result->resultCode was set in the callback. So we only overwrite
// it if there was a communication error indicated by the ErrorCode.
if (!rc.isOk()) {
result->resultCode = rc;
}
}
KeyStoreServiceReturnCode KeyStoreService::abort(const sp<IBinder>& token) {
km_device_t dev;
uint64_t handle;
KeyPurpose purpose;
km_id_t keyid;
if (!mOperationMap.getOperation(token, &handle, &keyid, &purpose, &dev, NULL)) {
return ErrorCode::INVALID_OPERATION_HANDLE;
}
mOperationMap.removeOperation(token);
ErrorCode rc = KS_HANDLE_HIDL_ERROR(dev->abort(handle));
mAuthTokenTable.MarkCompleted(handle);
return rc;
}
bool KeyStoreService::isOperationAuthorized(const sp<IBinder>& token) {
km_device_t dev;
uint64_t handle;
const KeyCharacteristics* characteristics;
KeyPurpose purpose;
km_id_t keyid;
if (!mOperationMap.getOperation(token, &handle, &keyid, &purpose, &dev, &characteristics)) {
return false;
}
const HardwareAuthToken* authToken = NULL;
mOperationMap.getOperationAuthToken(token, &authToken);
AuthorizationSet ignored;
auto authResult = addOperationAuthTokenIfNeeded(token, &ignored);
return authResult.isOk();
}
KeyStoreServiceReturnCode KeyStoreService::addAuthToken(const uint8_t* token, size_t length) {
// TODO(swillden): When gatekeeper and fingerprint are ready, this should be updated to
// receive a HardwareAuthToken, rather than an opaque byte array.
if (!checkBinderPermission(P_ADD_AUTH)) {
ALOGW("addAuthToken: permission denied for %d", IPCThreadState::self()->getCallingUid());
return ResponseCode::PERMISSION_DENIED;
}
if (length != sizeof(hw_auth_token_t)) {
return ErrorCode::INVALID_ARGUMENT;
}
hw_auth_token_t authToken;
memcpy(reinterpret_cast<void*>(&authToken), token, sizeof(hw_auth_token_t));
if (authToken.version != 0) {
return ErrorCode::INVALID_ARGUMENT;
}
std::unique_ptr<HardwareAuthToken> hidlAuthToken(new HardwareAuthToken);
hidlAuthToken->challenge = authToken.challenge;
hidlAuthToken->userId = authToken.user_id;
hidlAuthToken->authenticatorId = authToken.authenticator_id;
hidlAuthToken->authenticatorType = authToken.authenticator_type;
hidlAuthToken->timestamp = authToken.timestamp;
static_assert(
std::is_same<decltype(hidlAuthToken->hmac),
::android::hardware::hidl_array<uint8_t, sizeof(authToken.hmac)>>::value,
"This function assumes token HMAC is 32 bytes, but it might not be.");
std::copy(authToken.hmac, authToken.hmac + sizeof(authToken.hmac), hidlAuthToken->hmac.data());
// The table takes ownership of authToken.
mAuthTokenTable.AddAuthenticationToken(hidlAuthToken.release());
return ResponseCode::NO_ERROR;
}
bool isDeviceIdAttestationRequested(const hidl_vec<KeyParameter>& params) {
for (size_t i = 0; i < params.size(); ++i) {
switch (params[i].tag) {
case Tag::ATTESTATION_ID_BRAND:
case Tag::ATTESTATION_ID_DEVICE:
case Tag::ATTESTATION_ID_IMEI:
case Tag::ATTESTATION_ID_MANUFACTURER:
case Tag::ATTESTATION_ID_MEID:
case Tag::ATTESTATION_ID_MODEL:
case Tag::ATTESTATION_ID_PRODUCT:
case Tag::ATTESTATION_ID_SERIAL:
return true;
default:
break;
}
}
return false;
}
KeyStoreServiceReturnCode KeyStoreService::attestKey(const String16& name,
const hidl_vec<KeyParameter>& params,
hidl_vec<hidl_vec<uint8_t>>* outChain) {
if (!outChain) {
return ErrorCode::OUTPUT_PARAMETER_NULL;
}
if (!checkAllowedOperationParams(params)) {
return ErrorCode::INVALID_ARGUMENT;
}
if (isDeviceIdAttestationRequested(params)) {
// There is a dedicated attestDeviceIds() method for device ID attestation.
return ErrorCode::INVALID_ARGUMENT;
}
uid_t callingUid = IPCThreadState::self()->getCallingUid();
AuthorizationSet mutableParams = params;
KeyStoreServiceReturnCode rc = updateParamsForAttestation(callingUid, &mutableParams);
if (!rc.isOk()) {
return rc;
}
Blob keyBlob;
String8 name8(name);
rc = mKeyStore->getKeyForName(&keyBlob, name8, callingUid, TYPE_KEYMASTER_10);
if (!rc.isOk()) {
return rc;
}
KeyStoreServiceReturnCode error;
auto hidlCb = [&](ErrorCode ret, const hidl_vec<hidl_vec<uint8_t>>& certChain) {
error = ret;
if (!error.isOk()) {
return;
}
if (outChain) *outChain = certChain;
};
auto hidlKey = blob2hidlVec(keyBlob);
auto& dev = mKeyStore->getDevice(keyBlob);
rc = KS_HANDLE_HIDL_ERROR(dev->attestKey(hidlKey, mutableParams.hidl_data(), hidlCb));
if (!rc.isOk()) {
return rc;
}
return error;
}
KeyStoreServiceReturnCode KeyStoreService::attestDeviceIds(const hidl_vec<KeyParameter>& params,
hidl_vec<hidl_vec<uint8_t>>* outChain) {
if (!outChain) {
return ErrorCode::OUTPUT_PARAMETER_NULL;
}
if (!checkAllowedOperationParams(params)) {
return ErrorCode::INVALID_ARGUMENT;
}
if (!isDeviceIdAttestationRequested(params)) {
// There is an attestKey() method for attesting keys without device ID attestation.
return ErrorCode::INVALID_ARGUMENT;
}
uid_t callingUid = IPCThreadState::self()->getCallingUid();
sp<IBinder> binder = defaultServiceManager()->getService(String16("permission"));
if (binder == 0) {
return ErrorCode::CANNOT_ATTEST_IDS;
}
if (!interface_cast<IPermissionController>(binder)->checkPermission(
String16("android.permission.READ_PRIVILEGED_PHONE_STATE"),
IPCThreadState::self()->getCallingPid(), callingUid)) {
return ErrorCode::CANNOT_ATTEST_IDS;
}
AuthorizationSet mutableParams = params;
KeyStoreServiceReturnCode rc = updateParamsForAttestation(callingUid, &mutableParams);
if (!rc.isOk()) {
return rc;
}
// Generate temporary key.
auto& dev = mKeyStore->getDevice();
KeyStoreServiceReturnCode error;
hidl_vec<uint8_t> hidlKey;
AuthorizationSet keyCharacteristics;
keyCharacteristics.push_back(TAG_PURPOSE, KeyPurpose::VERIFY);
keyCharacteristics.push_back(TAG_ALGORITHM, Algorithm::EC);
keyCharacteristics.push_back(TAG_DIGEST, Digest::SHA_2_256);
keyCharacteristics.push_back(TAG_NO_AUTH_REQUIRED);
keyCharacteristics.push_back(TAG_EC_CURVE, EcCurve::P_256);
auto generateHidlCb = [&](ErrorCode ret, const hidl_vec<uint8_t>& hidlKeyBlob,
const KeyCharacteristics&) {
error = ret;
if (!error.isOk()) {
return;
}
hidlKey = hidlKeyBlob;
};
rc = KS_HANDLE_HIDL_ERROR(dev->generateKey(keyCharacteristics.hidl_data(), generateHidlCb));
if (!rc.isOk()) {
return rc;
}
if (!error.isOk()) {
return error;
}
// Attest key and device IDs.
auto attestHidlCb = [&](ErrorCode ret, const hidl_vec<hidl_vec<uint8_t>>& certChain) {
error = ret;
if (!error.isOk()) {
return;
}
*outChain = certChain;
};
KeyStoreServiceReturnCode attestationRc =
KS_HANDLE_HIDL_ERROR(dev->attestKey(hidlKey, mutableParams.hidl_data(), attestHidlCb));
// Delete temporary key.
KeyStoreServiceReturnCode deletionRc = KS_HANDLE_HIDL_ERROR(dev->deleteKey(hidlKey));
if (!attestationRc.isOk()) {
return attestationRc;
}
if (!error.isOk()) {
return error;
}
return deletionRc;
}
KeyStoreServiceReturnCode KeyStoreService::onDeviceOffBody() {
// TODO(tuckeris): add permission check. This should be callable from ClockworkHome only.
mAuthTokenTable.onDeviceOffBody();
return ResponseCode::NO_ERROR;
}
/**
* Prune the oldest pruneable operation.
*/
bool KeyStoreService::pruneOperation() {
sp<IBinder> oldest = mOperationMap.getOldestPruneableOperation();
ALOGD("Trying to prune operation %p", oldest.get());
size_t op_count_before_abort = mOperationMap.getOperationCount();
// We mostly ignore errors from abort() because all we care about is whether at least
// one operation has been removed.
int abort_error = abort(oldest);
if (mOperationMap.getOperationCount() >= op_count_before_abort) {
ALOGE("Failed to abort pruneable operation %p, error: %d", oldest.get(), abort_error);
return false;
}
return true;
}
/**
* Get the effective target uid for a binder operation that takes an
* optional uid as the target.
*/
uid_t KeyStoreService::getEffectiveUid(int32_t targetUid) {
if (targetUid == UID_SELF) {
return IPCThreadState::self()->getCallingUid();
}
return static_cast<uid_t>(targetUid);
}
/**
* Check if the caller of the current binder method has the required
* permission and if acting on other uids the grants to do so.
*/
bool KeyStoreService::checkBinderPermission(perm_t permission, int32_t targetUid) {
uid_t callingUid = IPCThreadState::self()->getCallingUid();
pid_t spid = IPCThreadState::self()->getCallingPid();
if (!has_permission(callingUid, permission, spid)) {
ALOGW("permission %s denied for %d", get_perm_label(permission), callingUid);
return false;
}
if (!is_granted_to(callingUid, getEffectiveUid(targetUid))) {
ALOGW("uid %d not granted to act for %d", callingUid, targetUid);
return false;
}
return true;
}
/**
* Check if the caller of the current binder method has the required
* permission and the target uid is the caller or the caller is system.
*/
bool KeyStoreService::checkBinderPermissionSelfOrSystem(perm_t permission, int32_t targetUid) {
uid_t callingUid = IPCThreadState::self()->getCallingUid();
pid_t spid = IPCThreadState::self()->getCallingPid();
if (!has_permission(callingUid, permission, spid)) {
ALOGW("permission %s denied for %d", get_perm_label(permission), callingUid);
return false;
}
return getEffectiveUid(targetUid) == callingUid || callingUid == AID_SYSTEM;
}
/**
* Check if the caller of the current binder method has the required
* permission or the target of the operation is the caller's uid. This is
* for operation where the permission is only for cross-uid activity and all
* uids are allowed to act on their own (ie: clearing all entries for a
* given uid).
*/
bool KeyStoreService::checkBinderPermissionOrSelfTarget(perm_t permission, int32_t targetUid) {
uid_t callingUid = IPCThreadState::self()->getCallingUid();
if (getEffectiveUid(targetUid) == callingUid) {
return true;
} else {
return checkBinderPermission(permission, targetUid);
}
}
/**
* Helper method to check that the caller has the required permission as
* well as the keystore is in the unlocked state if checkUnlocked is true.
*
* Returns NO_ERROR on success, PERMISSION_DENIED on a permission error and
* otherwise the state of keystore when not unlocked and checkUnlocked is
* true.
*/
KeyStoreServiceReturnCode
KeyStoreService::checkBinderPermissionAndKeystoreState(perm_t permission, int32_t targetUid,
bool checkUnlocked) {
if (!checkBinderPermission(permission, targetUid)) {
return ResponseCode::PERMISSION_DENIED;
}
State state = mKeyStore->getState(get_user_id(getEffectiveUid(targetUid)));
if (checkUnlocked && !isKeystoreUnlocked(state)) {
// All State values coincide with ResponseCodes
return static_cast<ResponseCode>(state);
}
return ResponseCode::NO_ERROR;
}
bool KeyStoreService::isKeystoreUnlocked(State state) {
switch (state) {
case ::STATE_NO_ERROR:
return true;
case ::STATE_UNINITIALIZED:
case ::STATE_LOCKED:
return false;
}
return false;
}
/**
* Check that all KeyParameter's provided by the application are
* allowed. Any parameter that keystore adds itself should be disallowed here.
*/
bool KeyStoreService::checkAllowedOperationParams(const hidl_vec<KeyParameter>& params) {
for (size_t i = 0; i < params.size(); ++i) {
switch (params[i].tag) {
case Tag::ATTESTATION_APPLICATION_ID:
case Tag::AUTH_TOKEN:
case Tag::RESET_SINCE_ID_ROTATION:
return false;
default:
break;
}
}
return true;
}
ErrorCode KeyStoreService::getOperationCharacteristics(const hidl_vec<uint8_t>& key,
km_device_t* dev,
const AuthorizationSet& params,
KeyCharacteristics* out) {
hidl_vec<uint8_t> appId;
hidl_vec<uint8_t> appData;
for (auto param : params) {
if (param.tag == Tag::APPLICATION_ID) {
appId = authorizationValue(TAG_APPLICATION_ID, param).value();
} else if (param.tag == Tag::APPLICATION_DATA) {
appData = authorizationValue(TAG_APPLICATION_DATA, param).value();
}
}
ErrorCode error = ErrorCode::OK;
auto hidlCb = [&](ErrorCode ret, const KeyCharacteristics& keyCharacteristics) {
error = ret;
if (error != ErrorCode::OK) {
return;
}
if (out) *out = keyCharacteristics;
};
ErrorCode rc = KS_HANDLE_HIDL_ERROR((*dev)->getKeyCharacteristics(key, appId, appData, hidlCb));
if (rc != ErrorCode::OK) {
return rc;
}
return error;
}
/**
* Get the auth token for this operation from the auth token table.
*
* Returns ResponseCode::NO_ERROR if the auth token was set or none was required.
* ::OP_AUTH_NEEDED if it is a per op authorization, no
* authorization token exists for that operation and
* failOnTokenMissing is false.
* KM_ERROR_KEY_USER_NOT_AUTHENTICATED if there is no valid auth
* token for the operation
*/
KeyStoreServiceReturnCode KeyStoreService::getAuthToken(const KeyCharacteristics& characteristics,
uint64_t handle, KeyPurpose purpose,
const HardwareAuthToken** authToken,
bool failOnTokenMissing) {
AuthorizationSet allCharacteristics;
for (size_t i = 0; i < characteristics.softwareEnforced.size(); i++) {
allCharacteristics.push_back(characteristics.softwareEnforced[i]);
}
for (size_t i = 0; i < characteristics.teeEnforced.size(); i++) {
allCharacteristics.push_back(characteristics.teeEnforced[i]);
}
AuthTokenTable::Error err =
mAuthTokenTable.FindAuthorization(allCharacteristics, purpose, handle, authToken);
switch (err) {
case AuthTokenTable::OK:
case AuthTokenTable::AUTH_NOT_REQUIRED:
return ResponseCode::NO_ERROR;
case AuthTokenTable::AUTH_TOKEN_NOT_FOUND:
case AuthTokenTable::AUTH_TOKEN_EXPIRED:
case AuthTokenTable::AUTH_TOKEN_WRONG_SID:
ALOGE("getAuthToken failed: %d", err); //STOPSHIP: debug only, to be removed
return ErrorCode::KEY_USER_NOT_AUTHENTICATED;
case AuthTokenTable::OP_HANDLE_REQUIRED:
return failOnTokenMissing ? KeyStoreServiceReturnCode(ErrorCode::KEY_USER_NOT_AUTHENTICATED)
: KeyStoreServiceReturnCode(ResponseCode::OP_AUTH_NEEDED);
default:
ALOGE("Unexpected FindAuthorization return value %d", err);
return ErrorCode::INVALID_ARGUMENT;
}
}
/**
* Add the auth token for the operation to the param list if the operation
* requires authorization. Uses the cached result in the OperationMap if available
* otherwise gets the token from the AuthTokenTable and caches the result.
*
* Returns ResponseCode::NO_ERROR if the auth token was added or not needed.
* KM_ERROR_KEY_USER_NOT_AUTHENTICATED if the operation is not
* authenticated.
* KM_ERROR_INVALID_OPERATION_HANDLE if token is not a valid
* operation token.
*/
KeyStoreServiceReturnCode KeyStoreService::addOperationAuthTokenIfNeeded(const sp<IBinder>& token,
AuthorizationSet* params) {
const HardwareAuthToken* authToken = nullptr;
mOperationMap.getOperationAuthToken(token, &authToken);
if (!authToken) {
km_device_t dev;
uint64_t handle;
const KeyCharacteristics* characteristics = nullptr;
KeyPurpose purpose;
km_id_t keyid;
if (!mOperationMap.getOperation(token, &handle, &keyid, &purpose, &dev, &characteristics)) {
return ErrorCode::INVALID_OPERATION_HANDLE;
}
auto result = getAuthToken(*characteristics, handle, purpose, &authToken);
if (!result.isOk()) {
return result;
}
if (authToken) {
mOperationMap.setOperationAuthToken(token, authToken);
}
}
addAuthTokenToParams(params, authToken);
return ResponseCode::NO_ERROR;
}
/**
* Translate a result value to a legacy return value. All keystore errors are
* preserved and keymaster errors become SYSTEM_ERRORs
*/
KeyStoreServiceReturnCode KeyStoreService::translateResultToLegacyResult(int32_t result) {
if (result > 0) {
return static_cast<ResponseCode>(result);
}
return ResponseCode::SYSTEM_ERROR;
}
static NullOr<const Algorithm&>
getKeyAlgoritmFromKeyCharacteristics(const KeyCharacteristics& characteristics) {
for (size_t i = 0; i < characteristics.teeEnforced.size(); ++i) {
auto algo = authorizationValue(TAG_ALGORITHM, characteristics.teeEnforced[i]);
if (algo.isOk()) return algo.value();
}
for (size_t i = 0; i < characteristics.softwareEnforced.size(); ++i) {
auto algo = authorizationValue(TAG_ALGORITHM, characteristics.softwareEnforced[i]);
if (algo.isOk()) return algo.value();
}
return {};
}
void KeyStoreService::addLegacyBeginParams(const String16& name, AuthorizationSet* params) {
// All legacy keys are DIGEST_NONE/PAD_NONE.
params->push_back(TAG_DIGEST, Digest::NONE);
params->push_back(TAG_PADDING, PaddingMode::NONE);
// Look up the algorithm of the key.
KeyCharacteristics characteristics;
auto rc = getKeyCharacteristics(name, hidl_vec<uint8_t>(), hidl_vec<uint8_t>(), UID_SELF,
&characteristics);
if (!rc.isOk()) {
ALOGE("Failed to get key characteristics");
return;
}
auto algorithm = getKeyAlgoritmFromKeyCharacteristics(characteristics);
if (!algorithm.isOk()) {
ALOGE("getKeyCharacteristics did not include KM_TAG_ALGORITHM");
return;
}
params->push_back(TAG_ALGORITHM, algorithm.value());
}
KeyStoreServiceReturnCode KeyStoreService::doLegacySignVerify(const String16& name,
const hidl_vec<uint8_t>& data,
hidl_vec<uint8_t>* out,
const hidl_vec<uint8_t>& signature,
KeyPurpose purpose) {
std::basic_stringstream<uint8_t> outBuffer;
OperationResult result;
AuthorizationSet inArgs;
addLegacyBeginParams(name, &inArgs);
sp<IBinder> appToken(new BBinder);
sp<IBinder> token;
begin(appToken, name, purpose, true, inArgs.hidl_data(), hidl_vec<uint8_t>(), UID_SELF,
&result);
if (!result.resultCode.isOk()) {
if (result.resultCode == ResponseCode::KEY_NOT_FOUND) {
ALOGW("Key not found");
} else {
ALOGW("Error in begin: %d", int32_t(result.resultCode));
}
return translateResultToLegacyResult(result.resultCode);
}
inArgs.Clear();
token = result.token;
size_t consumed = 0;
size_t lastConsumed = 0;
hidl_vec<uint8_t> data_view;
do {
data_view.setToExternal(const_cast<uint8_t*>(&data[consumed]), data.size() - consumed);
update(token, inArgs.hidl_data(), data_view, &result);
if (result.resultCode != ResponseCode::NO_ERROR) {
ALOGW("Error in update: %d", int32_t(result.resultCode));
return translateResultToLegacyResult(result.resultCode);
}
if (out) {
outBuffer.write(&result.data[0], result.data.size());
}
lastConsumed = result.inputConsumed;
consumed += lastConsumed;
} while (consumed < data.size() && lastConsumed > 0);
if (consumed != data.size()) {
ALOGW("Not all data consumed. Consumed %zu of %zu", consumed, data.size());
return ResponseCode::SYSTEM_ERROR;
}
finish(token, inArgs.hidl_data(), signature, hidl_vec<uint8_t>(), &result);
if (result.resultCode != ResponseCode::NO_ERROR) {
ALOGW("Error in finish: %d", int32_t(result.resultCode));
return translateResultToLegacyResult(result.resultCode);
}
if (out) {
outBuffer.write(&result.data[0], result.data.size());
}
if (out) {
auto buf = outBuffer.str();
out->resize(buf.size());
memcpy(&(*out)[0], buf.data(), out->size());
}
return ResponseCode::NO_ERROR;
}
KeyStoreServiceReturnCode KeyStoreService::upgradeKeyBlob(const String16& name, uid_t uid,
const AuthorizationSet& params,
Blob* blob) {
// Read the blob rather than assuming the caller provided the right name/uid/blob triplet.
String8 name8(name);
ResponseCode responseCode = mKeyStore->getKeyForName(blob, name8, uid, TYPE_KEYMASTER_10);
if (responseCode != ResponseCode::NO_ERROR) {
return responseCode;
}
ALOGI("upgradeKeyBlob %s %d", name8.string(), uid);
auto hidlKey = blob2hidlVec(*blob);
auto& dev = mKeyStore->getDevice(*blob);
KeyStoreServiceReturnCode error;
auto hidlCb = [&](ErrorCode ret, const hidl_vec<uint8_t>& upgradedKeyBlob) {
error = ret;
if (!error.isOk()) {
return;
}
auto filename = mKeyStore->getBlobFileNameIfExists(name8, uid, ::TYPE_KEYMASTER_10);
if (!filename.isOk()) {
ALOGI("trying to upgrade a non existing blob");
return;
}
error = mKeyStore->del(filename.value().string(), ::TYPE_ANY, get_user_id(uid));
if (!error.isOk()) {
ALOGI("upgradeKeyBlob keystore->del failed %d", (int)error);
return;
}
Blob newBlob(&upgradedKeyBlob[0], upgradedKeyBlob.size(), nullptr /* info */,
0 /* infoLength */, ::TYPE_KEYMASTER_10);
newBlob.setFallback(blob->isFallback());
newBlob.setEncrypted(blob->isEncrypted());
newBlob.setSuperEncrypted(blob->isSuperEncrypted());
newBlob.setCriticalToDeviceEncryption(blob->isCriticalToDeviceEncryption());
error = mKeyStore->put(filename.value().string(), &newBlob, get_user_id(uid));
if (!error.isOk()) {
ALOGI("upgradeKeyBlob keystore->put failed %d", (int)error);
return;
}
// Re-read blob for caller. We can't use newBlob because writing it modified it.
error = mKeyStore->getKeyForName(blob, name8, uid, TYPE_KEYMASTER_10);
};
KeyStoreServiceReturnCode rc =
KS_HANDLE_HIDL_ERROR(dev->upgradeKey(hidlKey, params.hidl_data(), hidlCb));
if (!rc.isOk()) {
return rc;
}
return error;
}
} // namespace keystore