1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <algorithm>
18
19#include <gtest/gtest.h>
20
21#include <openssl/engine.h>
22#include <openssl/rand.h>
23
24#include <keymaster/authorization_set.h>
25#include <keymaster/android_keymaster_utils.h>
26#include <keymaster/keymaster_tags.h>
27
28#include "android_keymaster_test_utils.h"
29#include "auth_encrypted_key_blob.h"
30#include "integrity_assured_key_blob.h"
31#include "ocb_utils.h"
32
33namespace keymaster {
34
35namespace test {
36
37const uint8_t master_key_data[16] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
38const uint8_t key_data[5] = {21, 22, 23, 24, 25};
39
40class KeyBlobTest : public testing::Test {
41  protected:
42    KeyBlobTest()
43        : master_key_(master_key_data, array_length(master_key_data)),
44          key_material_(key_data, array_length(key_data)) {
45        hw_enforced_.push_back(TAG_ALGORITHM, KM_ALGORITHM_RSA);
46        hw_enforced_.push_back(TAG_KEY_SIZE, 256);
47        hw_enforced_.push_back(TAG_BLOB_USAGE_REQUIREMENTS, KM_BLOB_STANDALONE);
48        hw_enforced_.push_back(TAG_MIN_SECONDS_BETWEEN_OPS, 10);
49        hw_enforced_.push_back(TAG_ALL_USERS);
50        hw_enforced_.push_back(TAG_NO_AUTH_REQUIRED);
51        hw_enforced_.push_back(TAG_ORIGIN, KM_ORIGIN_GENERATED);
52
53        sw_enforced_.push_back(TAG_ACTIVE_DATETIME, 10);
54        sw_enforced_.push_back(TAG_ORIGINATION_EXPIRE_DATETIME, 100);
55        sw_enforced_.push_back(TAG_CREATION_DATETIME, 10);
56
57        hidden_.push_back(TAG_ROOT_OF_TRUST, "foo", 3);
58        hidden_.push_back(TAG_APPLICATION_ID, "my_app", 6);
59
60        nonce_.reserve(OCB_NONCE_LENGTH);
61        EXPECT_EQ(1, RAND_bytes(nonce_.peek_write(), OCB_NONCE_LENGTH));
62        nonce_.advance_write(OCB_NONCE_LENGTH);
63
64        tag_.reserve(OCB_TAG_LENGTH);
65    }
66
67    keymaster_error_t Encrypt() {
68        return OcbEncryptKey(hw_enforced_, sw_enforced_, hidden_, master_key_, key_material_,
69                             nonce_, &ciphertext_, &tag_);
70    }
71
72    keymaster_error_t Decrypt() {
73        return OcbDecryptKey(hw_enforced_, sw_enforced_, hidden_, master_key_, ciphertext_, nonce_,
74                             tag_, &decrypted_plaintext_);
75    }
76
77    keymaster_error_t Serialize() {
78        return SerializeAuthEncryptedBlob(ciphertext_, hw_enforced_, sw_enforced_, nonce_, tag_,
79                                          &serialized_blob_);
80    }
81
82    keymaster_error_t Deserialize() {
83        return DeserializeAuthEncryptedBlob(serialized_blob_, &ciphertext_, &hw_enforced_,
84                                            &sw_enforced_, &nonce_, &tag_);
85    }
86
87    AuthorizationSet hw_enforced_;
88    AuthorizationSet sw_enforced_;
89    AuthorizationSet hidden_;
90    Buffer nonce_, tag_;
91
92    KeymasterKeyBlob master_key_;
93    KeymasterKeyBlob key_material_;
94    KeymasterKeyBlob ciphertext_;
95    KeymasterKeyBlob decrypted_plaintext_;
96    KeymasterKeyBlob serialized_blob_;
97};
98
99TEST_F(KeyBlobTest, EncryptDecrypt) {
100    ASSERT_EQ(KM_ERROR_OK, Encrypt());
101    ASSERT_EQ(KM_ERROR_OK, Serialize());
102
103    // key_data shouldn't be anywhere in the blob, ciphertext should.
104    EXPECT_EQ(serialized_blob_.end(), std::search(serialized_blob_.begin(), serialized_blob_.end(),
105                                                  key_material_.begin(), key_material_.end()));
106    EXPECT_NE(serialized_blob_.end(), std::search(serialized_blob_.begin(), serialized_blob_.end(),
107                                                  ciphertext_.begin(), ciphertext_.end()));
108
109    ciphertext_.Clear();
110    nonce_.Clear();
111    tag_.Clear();
112    AuthorizationSet hw2;
113    AuthorizationSet sw2;
114
115    ASSERT_EQ(KM_ERROR_OK, DeserializeAuthEncryptedBlob(serialized_blob_, &ciphertext_, &hw2, &sw2,
116                                                        &nonce_, &tag_));
117    KeymasterKeyBlob plaintext;
118    OcbDecryptKey(hw2, sw2, hidden_, master_key_, ciphertext_, nonce_, tag_, &plaintext);
119
120    EXPECT_EQ(hw_enforced_, hw2);
121    EXPECT_EQ(sw_enforced_, sw2);
122
123    ASSERT_EQ(key_material_.key_material_size, plaintext.key_material_size);
124    EXPECT_EQ(0, memcmp(plaintext.begin(), key_material_.begin(), plaintext.key_material_size));
125}
126
127TEST_F(KeyBlobTest, WrongKeyLength) {
128    ASSERT_EQ(KM_ERROR_OK, Encrypt());
129    ASSERT_EQ(KM_ERROR_OK, Serialize());
130
131    // Modify the key length, shouldn't be able to parse.
132    serialized_blob_.writable_data()[1 /* version */ + 4 /* nonce len */ + 12 /* nonce */ + 3]++;
133
134    ASSERT_EQ(KM_ERROR_INVALID_KEY_BLOB, Deserialize());
135}
136
137TEST_F(KeyBlobTest, WrongNonce) {
138    ASSERT_EQ(KM_ERROR_OK, Encrypt());
139    ASSERT_EQ(KM_ERROR_OK, Serialize());
140
141    // Find the nonce, then modify it.
142    auto nonce_ptr =
143        std::search(serialized_blob_.begin(), serialized_blob_.end(), nonce_.begin(), nonce_.end());
144    ASSERT_NE(nonce_ptr, serialized_blob_.end());
145    EXPECT_EQ(serialized_blob_.end(),
146              std::search(nonce_ptr + 1, serialized_blob_.end(), nonce_.begin(), nonce_.end()));
147    (*const_cast<uint8_t*>(nonce_ptr))++;
148
149    // Deserialization shouldn't be affected, but decryption should fail.
150    ASSERT_EQ(KM_ERROR_OK, Deserialize());
151    ASSERT_EQ(KM_ERROR_INVALID_KEY_BLOB, Decrypt());
152}
153
154TEST_F(KeyBlobTest, WrongTag) {
155    ASSERT_EQ(KM_ERROR_OK, Encrypt());
156    ASSERT_EQ(KM_ERROR_OK, Serialize());
157
158    // Find the tag, them modify it.
159    auto tag_ptr =
160        std::search(serialized_blob_.begin(), serialized_blob_.end(), tag_.begin(), tag_.end());
161    ASSERT_NE(tag_ptr, serialized_blob_.end());
162    EXPECT_EQ(serialized_blob_.end(),
163              std::search(tag_ptr + 1, serialized_blob_.end(), tag_.begin(), tag_.end()));
164    (*const_cast<uint8_t*>(tag_ptr))++;
165
166    // Deserialization shouldn't be affected, but decryption should fail.
167    ASSERT_EQ(KM_ERROR_OK, Deserialize());
168    ASSERT_EQ(KM_ERROR_INVALID_KEY_BLOB, Decrypt());
169}
170
171TEST_F(KeyBlobTest, WrongCiphertext) {
172    ASSERT_EQ(KM_ERROR_OK, Encrypt());
173    ASSERT_EQ(KM_ERROR_OK, Serialize());
174
175    // Find the ciphertext, them modify it.
176    auto ciphertext_ptr = std::search(serialized_blob_.begin(), serialized_blob_.end(),
177                                      ciphertext_.begin(), ciphertext_.end());
178    ASSERT_NE(ciphertext_ptr, serialized_blob_.end());
179    EXPECT_EQ(serialized_blob_.end(), std::search(ciphertext_ptr + 1, serialized_blob_.end(),
180                                                  ciphertext_.begin(), ciphertext_.end()));
181    (*const_cast<uint8_t*>(ciphertext_ptr))++;
182
183    // Deserialization shouldn't be affected, but decryption should fail.
184    ASSERT_EQ(KM_ERROR_OK, Deserialize());
185    ASSERT_EQ(KM_ERROR_INVALID_KEY_BLOB, Decrypt());
186}
187
188TEST_F(KeyBlobTest, WrongMasterKey) {
189    ASSERT_EQ(KM_ERROR_OK, Encrypt());
190    ASSERT_EQ(KM_ERROR_OK, Serialize());
191
192    uint8_t wrong_master_data[] = {1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
193    KeymasterKeyBlob wrong_master(wrong_master_data, array_length(wrong_master_data));
194
195    // Decrypting with wrong master key should fail.
196    ASSERT_EQ(KM_ERROR_OK, Deserialize());
197    ASSERT_EQ(KM_ERROR_INVALID_KEY_BLOB,
198              OcbDecryptKey(hw_enforced_, sw_enforced_, hidden_, wrong_master, ciphertext_, nonce_,
199                            tag_, &decrypted_plaintext_));
200}
201
202TEST_F(KeyBlobTest, WrongHwEnforced) {
203    ASSERT_EQ(KM_ERROR_OK, Encrypt());
204    ASSERT_EQ(KM_ERROR_OK, Serialize());
205
206    // Find enforced serialization data and modify it.
207    size_t hw_enforced_size = hw_enforced_.SerializedSize();
208    UniquePtr<uint8_t[]> hw_enforced_data(new uint8_t[hw_enforced_size]);
209    hw_enforced_.Serialize(hw_enforced_data.get(), hw_enforced_data.get() + hw_enforced_size);
210
211    auto hw_enforced_ptr =
212        std::search(serialized_blob_.begin(), serialized_blob_.end(), hw_enforced_data.get(),
213                    hw_enforced_data.get() + hw_enforced_size);
214    ASSERT_NE(serialized_blob_.end(), hw_enforced_ptr);
215    EXPECT_EQ(serialized_blob_.end(),
216              std::search(hw_enforced_ptr + 1, serialized_blob_.end(), hw_enforced_data.get(),
217                          hw_enforced_data.get() + hw_enforced_size));
218    (*(const_cast<uint8_t*>(hw_enforced_ptr) + hw_enforced_size - 1))++;
219
220    // Deserialization shouldn't be affected, but decryption should fail.
221    ASSERT_EQ(KM_ERROR_OK, Deserialize());
222    ASSERT_EQ(KM_ERROR_INVALID_KEY_BLOB, Decrypt());
223}
224
225TEST_F(KeyBlobTest, WrongSwEnforced) {
226    ASSERT_EQ(KM_ERROR_OK, Encrypt());
227    ASSERT_EQ(KM_ERROR_OK, Serialize());
228
229    // Find enforced serialization data and modify it.
230    size_t sw_enforced_size = sw_enforced_.SerializedSize();
231    UniquePtr<uint8_t[]> sw_enforced_data(new uint8_t[sw_enforced_size]);
232    sw_enforced_.Serialize(sw_enforced_data.get(), sw_enforced_data.get() + sw_enforced_size);
233
234    auto sw_enforced_ptr =
235        std::search(serialized_blob_.begin(), serialized_blob_.end(), sw_enforced_data.get(),
236                    sw_enforced_data.get() + sw_enforced_size);
237    ASSERT_NE(serialized_blob_.end(), sw_enforced_ptr);
238    EXPECT_EQ(serialized_blob_.end(),
239              std::search(sw_enforced_ptr + 1, serialized_blob_.end(), sw_enforced_data.get(),
240                          sw_enforced_data.get() + sw_enforced_size));
241    (*(const_cast<uint8_t*>(sw_enforced_ptr) + sw_enforced_size - 1))++;
242
243    // Deserialization shouldn't be affected, but decryption should fail.
244    ASSERT_EQ(KM_ERROR_OK, Deserialize());
245    ASSERT_EQ(KM_ERROR_INVALID_KEY_BLOB, Decrypt());
246}
247
248TEST_F(KeyBlobTest, EmptyHidden) {
249    ASSERT_EQ(KM_ERROR_OK, Encrypt());
250    ASSERT_EQ(KM_ERROR_OK, Serialize());
251
252    AuthorizationSet wrong_hidden;
253
254    // Deserialization shouldn't be affected, but decryption should fail.
255    ASSERT_EQ(KM_ERROR_OK, Deserialize());
256    EXPECT_EQ(KM_ERROR_INVALID_KEY_BLOB,
257              OcbDecryptKey(hw_enforced_, sw_enforced_, wrong_hidden, master_key_, ciphertext_,
258                            nonce_, tag_, &decrypted_plaintext_));
259}
260
261TEST_F(KeyBlobTest, WrongRootOfTrust) {
262    ASSERT_EQ(KM_ERROR_OK, Encrypt());
263    ASSERT_EQ(KM_ERROR_OK, Serialize());
264
265    AuthorizationSet wrong_hidden;
266    wrong_hidden.push_back(TAG_ROOT_OF_TRUST, "bar", 2);
267    wrong_hidden.push_back(TAG_APPLICATION_ID, "my_app", 6);
268
269    // Deserialization shouldn't be affected, but decryption should fail.
270    ASSERT_EQ(KM_ERROR_OK, Deserialize());
271    EXPECT_EQ(KM_ERROR_INVALID_KEY_BLOB,
272              OcbDecryptKey(hw_enforced_, sw_enforced_, wrong_hidden, master_key_, ciphertext_,
273                            nonce_, tag_, &decrypted_plaintext_));
274}
275
276TEST_F(KeyBlobTest, WrongAppId) {
277    ASSERT_EQ(KM_ERROR_OK, Encrypt());
278    ASSERT_EQ(KM_ERROR_OK, Serialize());
279
280    AuthorizationSet wrong_hidden;
281    wrong_hidden.push_back(TAG_ROOT_OF_TRUST, "foo", 3);
282    wrong_hidden.push_back(TAG_APPLICATION_ID, "your_app", 7);
283
284    // Deserialization shouldn't be affected, but decryption should fail.
285    ASSERT_EQ(KM_ERROR_OK, Deserialize());
286    EXPECT_EQ(KM_ERROR_INVALID_KEY_BLOB,
287              OcbDecryptKey(hw_enforced_, sw_enforced_, wrong_hidden, master_key_, ciphertext_,
288                            nonce_, tag_, &decrypted_plaintext_));
289}
290
291// This test is especially useful when compiled for 32-bit mode and run under valgrind.
292TEST_F(KeyBlobTest, FuzzTest) {
293    time_t now = time(NULL);
294    std::cout << "Seeding rand() with " << now << " for fuzz test." << std::endl;
295    srand(now);
296
297    // Fill large buffer with random bytes.
298    const int kBufSize = 10000;
299    UniquePtr<uint8_t[]> buf(new uint8_t[kBufSize]);
300    for (size_t i = 0; i < kBufSize; ++i)
301        buf[i] = static_cast<uint8_t>(rand());
302
303    // Try to deserialize every offset with multiple methods.
304    size_t deserialize_auth_encrypted_success = 0;
305    for (size_t i = 0; i < kBufSize; ++i) {
306        keymaster_key_blob_t blob = {buf.get() + i, kBufSize - i};
307        KeymasterKeyBlob key_blob(blob);
308
309        // Integrity-assured blob.
310        ASSERT_EQ(KM_ERROR_INVALID_KEY_BLOB,
311                  DeserializeIntegrityAssuredBlob(key_blob, hidden_, &key_material_, &hw_enforced_,
312                                                  &sw_enforced_));
313
314        // Auth-encrypted OCB blob.
315        keymaster_error_t error = DeserializeAuthEncryptedBlob(
316            key_blob, &ciphertext_, &hw_enforced_, &sw_enforced_, &nonce_, &tag_);
317        if (error == KM_ERROR_OK) {
318            // It's possible to deserialize successfully.  Decryption should always fail.
319            ++deserialize_auth_encrypted_success;
320            error = OcbDecryptKey(hw_enforced_, sw_enforced_, hidden_, master_key_, ciphertext_,
321                                  nonce_, tag_, &decrypted_plaintext_);
322        }
323        ASSERT_EQ(KM_ERROR_INVALID_KEY_BLOB, error)
324            << "Somehow sucessfully parsed a blob with seed " << now << " at offset " << i;
325    }
326}
327
328TEST_F(KeyBlobTest, UnderflowTest) {
329    uint8_t buf[0];
330    keymaster_key_blob_t blob = {buf, 0};
331    KeymasterKeyBlob key_blob(blob);
332    EXPECT_NE(nullptr, key_blob.key_material);
333    EXPECT_EQ(0U, key_blob.key_material_size);
334
335    EXPECT_EQ(KM_ERROR_INVALID_KEY_BLOB,
336              DeserializeIntegrityAssuredBlob(key_blob, hidden_, &key_material_, &hw_enforced_,
337                                              &sw_enforced_));
338
339    EXPECT_EQ(KM_ERROR_INVALID_KEY_BLOB,
340              DeserializeAuthEncryptedBlob(key_blob, &ciphertext_, &hw_enforced_, &sw_enforced_,
341                                           &nonce_, &tag_));
342}
343
344TEST_F(KeyBlobTest, DupBufferToolarge) {
345    uint8_t buf[0];
346    keymaster_key_blob_t blob = {buf, 0};
347    blob.key_material_size = 16 * 1024 * 1024 + 1;
348    KeymasterKeyBlob key_blob(blob);
349    EXPECT_EQ(nullptr, key_blob.key_material);
350    EXPECT_EQ(0U, key_blob.key_material_size);
351
352    ASSERT_EQ(KM_ERROR_INVALID_KEY_BLOB,
353              DeserializeIntegrityAssuredBlob(key_blob, hidden_, &key_material_, &hw_enforced_,
354                                              &sw_enforced_));
355
356    EXPECT_EQ(KM_ERROR_INVALID_KEY_BLOB,
357              DeserializeAuthEncryptedBlob(key_blob, &ciphertext_, &hw_enforced_, &sw_enforced_,
358                                           &nonce_, &tag_));
359}
360
361}  // namespace test
362}  // namespace keymaster
363