1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
/*
* 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 <openssl/sha.h>
#include <crypto_scrypt.h>
}
#include <android-base/memory.h>
#include <gatekeeper/gatekeeper.h>
#include <iostream>
#include <unordered_map>
#include <memory>
namespace gatekeeper {
struct fast_hash_t {
uint64_t salt;
uint8_t digest[SHA256_DIGEST_LENGTH];
};
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() {
key_.reset(new uint8_t[SIGNATURE_LENGTH_BYTES]);
memset(key_.get(), 0, SIGNATURE_LENGTH_BYTES);
}
virtual ~SoftGateKeeper() {
}
virtual bool GetAuthTokenKey(const uint8_t **auth_token_key,
uint32_t *length) const {
if (auth_token_key == NULL || length == NULL) return false;
uint8_t *auth_token_key_copy = new uint8_t[SIGNATURE_LENGTH_BYTES];
memcpy(auth_token_key_copy, key_.get(), SIGNATURE_LENGTH_BYTES);
*auth_token_key = auth_token_key_copy;
*length = SIGNATURE_LENGTH_BYTES;
return true;
}
virtual void GetPasswordKey(const uint8_t **password_key, uint32_t *length) {
if (password_key == NULL || length == NULL) return;
uint8_t *password_key_copy = new uint8_t[SIGNATURE_LENGTH_BYTES];
memcpy(password_key_copy, key_.get(), SIGNATURE_LENGTH_BYTES);
*password_key = password_key_copy;
*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 uint64_t GetMillisecondsSinceBoot() const {
struct timespec time;
int res = clock_gettime(CLOCK_BOOTTIME, &time);
if (res < 0) return 0;
return (time.tv_sec * 1000) + (time.tv_nsec / 1000 / 1000);
}
virtual bool IsHardwareBacked() const {
return false;
}
virtual bool GetFailureRecord(uint32_t uid, secure_id_t user_id, failure_record_t *record,
bool /* secure */) {
failure_record_t *stored = &failure_map_[uid];
if (user_id != stored->secure_user_id) {
stored->secure_user_id = user_id;
stored->last_checked_timestamp = 0;
stored->failure_counter = 0;
}
memcpy(record, stored, sizeof(*record));
return true;
}
virtual bool ClearFailureRecord(uint32_t uid, secure_id_t user_id, bool /* secure */) {
failure_record_t *stored = &failure_map_[uid];
stored->secure_user_id = user_id;
stored->last_checked_timestamp = 0;
stored->failure_counter = 0;
return true;
}
virtual bool WriteFailureRecord(uint32_t uid, failure_record_t *record, bool /* secure */) {
failure_map_[uid] = *record;
return true;
}
fast_hash_t ComputeFastHash(const SizedBuffer &password, uint64_t salt) {
fast_hash_t fast_hash;
size_t digest_size = password.length + sizeof(salt);
std::unique_ptr<uint8_t[]> digest(new uint8_t[digest_size]);
memcpy(digest.get(), &salt, sizeof(salt));
memcpy(digest.get() + sizeof(salt), password.buffer.get(), password.length);
SHA256(digest.get(), digest_size, (uint8_t *) &fast_hash.digest);
fast_hash.salt = salt;
return fast_hash;
}
bool VerifyFast(const fast_hash_t &fast_hash, const SizedBuffer &password) {
fast_hash_t computed = ComputeFastHash(password, fast_hash.salt);
return memcmp(computed.digest, fast_hash.digest, SHA256_DIGEST_LENGTH) == 0;
}
bool DoVerify(const password_handle_t *expected_handle, const SizedBuffer &password) {
uint64_t user_id = android::base::get_unaligned<secure_id_t>(&expected_handle->user_id);
FastHashMap::const_iterator it = fast_hash_map_.find(user_id);
if (it != fast_hash_map_.end() && VerifyFast(it->second, password)) {
return true;
} else {
if (GateKeeper::DoVerify(expected_handle, password)) {
uint64_t salt;
GetRandom(&salt, sizeof(salt));
fast_hash_map_[user_id] = ComputeFastHash(password, salt);
return true;
}
}
return false;
}
private:
typedef std::unordered_map<uint32_t, failure_record_t> FailureRecordMap;
typedef std::unordered_map<uint64_t, fast_hash_t> FastHashMap;
std::unique_ptr<uint8_t[]> key_;
FailureRecordMap failure_map_;
FastHashMap fast_hash_map_;
};
}
#endif // SOFT_GATEKEEPER_H_
|
