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/*
* Copyright 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.
*
*/
#ifndef SOFT_GATEKEEPER_H_
#define SOFT_GATEKEEPER_H_
extern "C" {
#include <openssl/rand.h>
#include <crypto_scrypt.h>
}
#include <UniquePtr.h>
#include <gatekeeper/gatekeeper.h>
#include <iostream>
namespace gatekeeper {
/**
* Convenience class for easily switching out a testing implementation
*/
class GateKeeperFileIo {
public:
virtual ~GateKeeperFileIo() {}
virtual void Write(const char *filename, const uint8_t *bytes, uint32_t length) = 0;
virtual uint32_t Read(const char *filename, UniquePtr<uint8_t> *bytes) const = 0;
};
class SoftGateKeeper : public GateKeeper {
public:
static const uint32_t SIGNATURE_LENGTH_BYTES = 32;
// scrypt params
static const uint64_t N = 16384;
static const uint32_t r = 8;
static const uint32_t p = 1;
static const int MAX_UINT_32_CHARS = 11;
SoftGateKeeper(GateKeeperFileIo *file_io) {
file_io_ = file_io;
key_.reset(new uint8_t[SIGNATURE_LENGTH_BYTES]);
memset(key_.get(), 0, SIGNATURE_LENGTH_BYTES);
}
virtual ~SoftGateKeeper() {
delete file_io_;
}
virtual void GetAuthTokenKey(const uint8_t **auth_token_key,
uint32_t *length) const {
if (auth_token_key == NULL || length == NULL) return;
*auth_token_key = const_cast<const uint8_t *>(key_.get());
*length = SIGNATURE_LENGTH_BYTES;
}
virtual void GetPasswordKey(const uint8_t **password_key, uint32_t *length) {
if (password_key == NULL || length == NULL) return;
*password_key = const_cast<const uint8_t *>(key_.get());
*length = SIGNATURE_LENGTH_BYTES;
}
virtual void ComputePasswordSignature(uint8_t *signature, uint32_t signature_length,
const uint8_t *, uint32_t, const uint8_t *password,
uint32_t password_length, salt_t salt) const {
if (signature == NULL) return;
crypto_scrypt(password, password_length, reinterpret_cast<uint8_t *>(&salt),
sizeof(salt), N, r, p, signature, signature_length);
}
virtual void GetRandom(void *random, uint32_t requested_length) const {
if (random == NULL) return;
RAND_pseudo_bytes((uint8_t *) random, requested_length);
}
virtual void ComputeSignature(uint8_t *signature, uint32_t signature_length,
const uint8_t *, uint32_t, const uint8_t *, const uint32_t) const {
if (signature == NULL) return;
memset(signature, 0, signature_length);
}
virtual void ReadPasswordFile(uint32_t uid, SizedBuffer *password_file) const {
char buf[MAX_UINT_32_CHARS];
sprintf(buf, "%u", uid);
UniquePtr<uint8_t> password_buffer;
uint32_t length = file_io_->Read(buf, &password_buffer);
password_file->buffer.reset(password_buffer.release());
password_file->length = length;
}
virtual void WritePasswordFile(uint32_t uid, const SizedBuffer &password_file) const {
char buf[MAX_UINT_32_CHARS];
sprintf(buf, "%u", uid);
file_io_->Write(buf, password_file.buffer.get(), password_file.length);
}
virtual uint64_t GetNanosecondsSinceBoot() const {
struct timespec time;
int res = clock_gettime(CLOCK_MONOTONIC_RAW, &time);
if (res < 0) return 0;
return time.tv_nsec;
}
private:
GateKeeperFileIo *file_io_;
UniquePtr<uint8_t> key_;
};
}
#endif // SOFT_GATEKEEPER_H_
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