/*
* Copyright (C) 2015 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 "gatekeeperd"
#include "IGateKeeperService.h"
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <stdint.h>
#include <unistd.h>
#include <binder/IPCThreadState.h>
#include <binder/IServiceManager.h>
#include <binder/PermissionCache.h>
#include <gatekeeper/password_handle.h> // for password_handle_t
#include <hardware/gatekeeper.h>
#include <hardware/hw_auth_token.h>
#include <keystore/IKeystoreService.h>
#include <keystore/keystore.h> // For error code
#include <log/log.h>
#include <utils/Log.h>
#include <utils/String16.h>
#include "SoftGateKeeperDevice.h"
#include "IUserManager.h"
#include <hidl/HidlSupport.h>
#include <android/hardware/gatekeeper/1.0/IGatekeeper.h>
using android::sp;
using android::hardware::gatekeeper::V1_0::IGatekeeper;
using android::hardware::gatekeeper::V1_0::GatekeeperStatusCode;
using android::hardware::gatekeeper::V1_0::GatekeeperResponse;
using android::hardware::Return;
namespace android {
static const String16 KEYGUARD_PERMISSION("android.permission.ACCESS_KEYGUARD_SECURE_STORAGE");
static const String16 DUMP_PERMISSION("android.permission.DUMP");
class GateKeeperProxy : public BnGateKeeperService {
public:
GateKeeperProxy() {
hw_device = IGatekeeper::getService();
if (hw_device == nullptr) {
ALOGW("falling back to software GateKeeper");
soft_device.reset(new SoftGateKeeperDevice());
}
if (mark_cold_boot()) {
ALOGI("cold boot: clearing state");
if (hw_device != nullptr) {
hw_device->deleteAllUsers([](const GatekeeperResponse &){});
}
}
}
virtual ~GateKeeperProxy() {
}
void store_sid(uint32_t uid, uint64_t sid) {
char filename[21];
snprintf(filename, sizeof(filename), "%u", uid);
int fd = open(filename, O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IWUSR);
if (fd < 0) {
ALOGE("could not open file: %s: %s", filename, strerror(errno));
return;
}
write(fd, &sid, sizeof(sid));
close(fd);
}
bool mark_cold_boot() {
const char *filename = ".coldboot";
if (access(filename, F_OK) == -1) {
int fd = open(filename, O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IWUSR);
if (fd < 0) {
ALOGE("could not open file: %s : %s", filename, strerror(errno));
return false;
}
close(fd);
return true;
}
return false;
}
void maybe_store_sid(uint32_t uid, uint64_t sid) {
char filename[21];
snprintf(filename, sizeof(filename), "%u", uid);
if (access(filename, F_OK) == -1) {
store_sid(uid, sid);
}
}
uint64_t read_sid(uint32_t uid) {
char filename[21];
uint64_t sid;
snprintf(filename, sizeof(filename), "%u", uid);
int fd = open(filename, O_RDONLY);
if (fd < 0) return 0;
read(fd, &sid, sizeof(sid));
close(fd);
return sid;
}
void clear_sid(uint32_t uid) {
char filename[21];
snprintf(filename, sizeof(filename), "%u", uid);
if (remove(filename) < 0) {
ALOGE("%s: could not remove file [%s], attempting 0 write", __func__, strerror(errno));
store_sid(uid, 0);
}
}
virtual int enroll(uint32_t uid,
const uint8_t *current_password_handle, uint32_t current_password_handle_length,
const uint8_t *current_password, uint32_t current_password_length,
const uint8_t *desired_password, uint32_t desired_password_length,
uint8_t **enrolled_password_handle, uint32_t *enrolled_password_handle_length) {
IPCThreadState* ipc = IPCThreadState::self();
const int calling_pid = ipc->getCallingPid();
const int calling_uid = ipc->getCallingUid();
if (!PermissionCache::checkPermission(KEYGUARD_PERMISSION, calling_pid, calling_uid)) {
return PERMISSION_DENIED;
}
// need a desired password to enroll
if (desired_password_length == 0) return -EINVAL;
int ret;
if (hw_device != nullptr) {
const gatekeeper::password_handle_t *handle =
reinterpret_cast<const gatekeeper::password_handle_t *>(current_password_handle);
if (handle != NULL && handle->version != 0 && !handle->hardware_backed) {
// handle is being re-enrolled from a software version. HAL probably won't accept
// the handle as valid, so we nullify it and enroll from scratch
current_password_handle = NULL;
current_password_handle_length = 0;
current_password = NULL;
current_password_length = 0;
}
android::hardware::hidl_vec<uint8_t> curPwdHandle;
curPwdHandle.setToExternal(const_cast<uint8_t*>(current_password_handle),
current_password_handle_length);
android::hardware::hidl_vec<uint8_t> curPwd;
curPwd.setToExternal(const_cast<uint8_t*>(current_password),
current_password_length);
android::hardware::hidl_vec<uint8_t> newPwd;
newPwd.setToExternal(const_cast<uint8_t*>(desired_password),
desired_password_length);
Return<void> hwRes = hw_device->enroll(uid, curPwdHandle, curPwd, newPwd,
[&ret, enrolled_password_handle, enrolled_password_handle_length]
(const GatekeeperResponse &rsp) {
ret = static_cast<int>(rsp.code); // propagate errors
if (rsp.code >= GatekeeperStatusCode::STATUS_OK) {
if (enrolled_password_handle != nullptr &&
enrolled_password_handle_length != nullptr) {
*enrolled_password_handle = new uint8_t[rsp.data.size()];
*enrolled_password_handle_length = rsp.data.size();
memcpy(*enrolled_password_handle, rsp.data.data(),
*enrolled_password_handle_length);
}
ret = 0; // all success states are reported as 0
} else if (rsp.code == GatekeeperStatusCode::ERROR_RETRY_TIMEOUT && rsp.timeout > 0) {
ret = rsp.timeout;
}
});
if (!hwRes.isOk()) {
ALOGE("enroll transaction failed\n");
ret = -1;
}
} else {
ret = soft_device->enroll(uid,
current_password_handle, current_password_handle_length,
current_password, current_password_length,
desired_password, desired_password_length,
enrolled_password_handle, enrolled_password_handle_length);
}
if (ret == GATEKEEPER_RESPONSE_OK && (*enrolled_password_handle == nullptr ||
*enrolled_password_handle_length != sizeof(password_handle_t))) {
ret = GATEKEEPER_RESPONSE_ERROR;
ALOGE("HAL: password_handle=%p size_of_handle=%" PRIu32 "\n",
*enrolled_password_handle, *enrolled_password_handle_length);
}
if (ret == GATEKEEPER_RESPONSE_OK) {
gatekeeper::password_handle_t *handle =
reinterpret_cast<gatekeeper::password_handle_t *>(*enrolled_password_handle);
store_sid(uid, handle->user_id);
bool rr;
// immediately verify this password so we don't ask the user to enter it again
// if they just created it.
verify(uid, *enrolled_password_handle, sizeof(password_handle_t), desired_password,
desired_password_length, &rr);
}
return ret;
}
virtual int verify(uint32_t uid,
const uint8_t *enrolled_password_handle, uint32_t enrolled_password_handle_length,
const uint8_t *provided_password, uint32_t provided_password_length, bool *request_reenroll) {
uint8_t *auth_token;
uint32_t auth_token_length;
return verifyChallenge(uid, 0, enrolled_password_handle, enrolled_password_handle_length,
provided_password, provided_password_length,
&auth_token, &auth_token_length, request_reenroll);
}
virtual int verifyChallenge(uint32_t uid, uint64_t challenge,
const uint8_t *enrolled_password_handle, uint32_t enrolled_password_handle_length,
const uint8_t *provided_password, uint32_t provided_password_length,
uint8_t **auth_token, uint32_t *auth_token_length, bool *request_reenroll) {
IPCThreadState* ipc = IPCThreadState::self();
const int calling_pid = ipc->getCallingPid();
const int calling_uid = ipc->getCallingUid();
if (!PermissionCache::checkPermission(KEYGUARD_PERMISSION, calling_pid, calling_uid)) {
return PERMISSION_DENIED;
}
// can't verify if we're missing either param
if ((enrolled_password_handle_length | provided_password_length) == 0)
return -EINVAL;
int ret;
if (hw_device != nullptr) {
const gatekeeper::password_handle_t *handle =
reinterpret_cast<const gatekeeper::password_handle_t *>(enrolled_password_handle);
// handle version 0 does not have hardware backed flag, and thus cannot be upgraded to
// a HAL if there was none before
if (handle->version == 0 || handle->hardware_backed) {
android::hardware::hidl_vec<uint8_t> curPwdHandle;
curPwdHandle.setToExternal(const_cast<uint8_t*>(enrolled_password_handle),
enrolled_password_handle_length);
android::hardware::hidl_vec<uint8_t> enteredPwd;
enteredPwd.setToExternal(const_cast<uint8_t*>(provided_password),
provided_password_length);
Return<void> hwRes = hw_device->verify(uid, challenge, curPwdHandle, enteredPwd,
[&ret, request_reenroll, auth_token, auth_token_length]
(const GatekeeperResponse &rsp) {
ret = static_cast<int>(rsp.code); // propagate errors
if (auth_token != nullptr && auth_token_length != nullptr &&
rsp.code >= GatekeeperStatusCode::STATUS_OK) {
*auth_token = new uint8_t[rsp.data.size()];
*auth_token_length = rsp.data.size();
memcpy(*auth_token, rsp.data.data(), *auth_token_length);
if (request_reenroll != nullptr) {
*request_reenroll = (rsp.code == GatekeeperStatusCode::STATUS_REENROLL);
}
ret = 0; // all success states are reported as 0
} else if (rsp.code == GatekeeperStatusCode::ERROR_RETRY_TIMEOUT &&
rsp.timeout > 0) {
ret = rsp.timeout;
}
});
if (!hwRes.isOk()) {
ALOGE("verify transaction failed\n");
ret = -1;
}
} else {
// upgrade scenario, a HAL has been added to this device where there was none before
SoftGateKeeperDevice soft_dev;
ret = soft_dev.verify(uid, challenge,
enrolled_password_handle, enrolled_password_handle_length,
provided_password, provided_password_length, auth_token, auth_token_length,
request_reenroll);
if (ret == 0) {
// success! re-enroll with HAL
*request_reenroll = true;
}
}
} else {
ret = soft_device->verify(uid, challenge,
enrolled_password_handle, enrolled_password_handle_length,
provided_password, provided_password_length, auth_token, auth_token_length,
request_reenroll);
}
if (ret == 0 && *auth_token != NULL && *auth_token_length > 0) {
// TODO: cache service?
sp<IServiceManager> sm = defaultServiceManager();
sp<IBinder> binder = sm->getService(String16("android.security.keystore"));
sp<IKeystoreService> service = interface_cast<IKeystoreService>(binder);
if (service != NULL) {
auto ret = service->addAuthToken(*auth_token, *auth_token_length);
if (!ret.isOk()) {
ALOGE("Failure sending auth token to KeyStore: %" PRId32, int32_t(ret));
}
} else {
ALOGE("Unable to communicate with KeyStore");
}
}
if (ret == 0) {
maybe_store_sid(uid, reinterpret_cast<const gatekeeper::password_handle_t *>(
enrolled_password_handle)->user_id);
}
return ret;
}
virtual uint64_t getSecureUserId(uint32_t uid) {
uint64_t sid = read_sid(uid);
if (sid == 0) {
// might be a work profile, look up the parent
sp<IServiceManager> sm = defaultServiceManager();
sp<IBinder> binder = sm->getService(String16("user"));
sp<IUserManager> um = interface_cast<IUserManager>(binder);
int32_t parent = um->getCredentialOwnerProfile(uid);
if (parent < 0) {
return 0;
} else if (parent != (int32_t) uid) {
return read_sid(parent);
}
}
return sid;
}
virtual void clearSecureUserId(uint32_t uid) {
IPCThreadState* ipc = IPCThreadState::self();
const int calling_pid = ipc->getCallingPid();
const int calling_uid = ipc->getCallingUid();
if (!PermissionCache::checkPermission(KEYGUARD_PERMISSION, calling_pid, calling_uid)) {
ALOGE("%s: permission denied for [%d:%d]", __func__, calling_pid, calling_uid);
return;
}
clear_sid(uid);
if (hw_device != nullptr) {
hw_device->deleteUser(uid, [] (const GatekeeperResponse &){});
}
}
virtual status_t dump(int fd, const Vector<String16> &) {
IPCThreadState* ipc = IPCThreadState::self();
const int pid = ipc->getCallingPid();
const int uid = ipc->getCallingUid();
if (!PermissionCache::checkPermission(DUMP_PERMISSION, pid, uid)) {
return PERMISSION_DENIED;
}
if (hw_device == NULL) {
const char *result = "Device not available";
write(fd, result, strlen(result) + 1);
} else {
const char *result = "OK";
write(fd, result, strlen(result) + 1);
}
return NO_ERROR;
}
private:
sp<IGatekeeper> hw_device;
UniquePtr<SoftGateKeeperDevice> soft_device;
};
}// namespace android
int main(int argc, char* argv[]) {
ALOGI("Starting gatekeeperd...");
if (argc < 2) {
ALOGE("A directory must be specified!");
return 1;
}
if (chdir(argv[1]) == -1) {
ALOGE("chdir: %s: %s", argv[1], strerror(errno));
return 1;
}
android::sp<android::IServiceManager> sm = android::defaultServiceManager();
android::sp<android::GateKeeperProxy> proxy = new android::GateKeeperProxy();
android::status_t ret = sm->addService(
android::String16("android.service.gatekeeper.IGateKeeperService"), proxy);
if (ret != android::OK) {
ALOGE("Couldn't register binder service!");
return -1;
}
/*
* We're the only thread in existence, so we're just going to process
* Binder transaction as a single-threaded program.
*/
android::IPCThreadState::self()->joinThreadPool();
return 0;
}