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
|
// Copyright 2018 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Fuzzer for the TPM2 and vendor specific Cr50 commands.
#include <unistd.h>
#include <cassert>
#include <cstdint>
#include <cstring>
#include <unordered_map>
#include <vector>
#include <src/libfuzzer/libfuzzer_macro.h>
#include <src/mutator.h>
#define HIDE_EC_STDLIB
#include "chip/host/persistence.h"
#include "fuzz/cr50_fuzz.pb.h"
#include "fuzz/fuzz_config.h"
#include "fuzz/pinweaver_model.h"
#include "fuzz/span.h"
#include "include/nvmem.h"
#include "include/nvmem_vars.h"
#include "include/pinweaver.h"
using protobuf_mutator::libfuzzer::LoadProtoInput;
namespace {
constexpr size_t kBufferAlignment = alignof(pw_request_t) >
alignof(pw_response_t)
? alignof(pw_request_t)
: alignof(pw_response_t);
} // namespace
extern "C" uint32_t nvmem_user_sizes[NVMEM_NUM_USERS] = {NVMEM_TPM_SIZE,
NVMEM_CR50_SIZE};
extern "C" void rand_bytes(void* data, size_t len) {
size_t x = 0;
uint8_t* buffer = reinterpret_cast<uint8_t*>(data);
for (; x < len; ++x) {
buffer[x] = rand();
}
}
extern "C" void get_storage_seed(void* buf, size_t* len) {
memset(buf, 0x77, *len);
}
extern "C" uint8_t get_current_pcr_digest(const uint8_t bitmask[2],
uint8_t sha256_of_selected_pcr[32]) {
memset(sha256_of_selected_pcr, 0, 32);
return 0;
}
extern "C" int DCRYPTO_ladder_is_enabled(void) {
return 1;
}
extern "C" void nvmem_wipe_cache(void) {
// Nothing to do since there is no cache in this implementation.
}
// Needed for test targets to build.
extern "C" void run_test(void) {}
void InitializeFuzzerRun() {
memset(__host_flash, 0xff, sizeof(__host_flash));
nvmem_init();
nvmem_enable_commits();
srand(0);
}
// Used to verify the model hasn't become out of sync with the implementation.
// The usefulness of this fuzzer comes from its ability to reach all the code
// paths.
bool SelfTest() {
InitializeFuzzerRun();
PinweaverModel pinweaver_model;
alignas(kBufferAlignment) uint8_t buffer[PW_MAX_MESSAGE_SIZE] = {};
fuzz::span<uint8_t> buffer_view(buffer, sizeof(buffer));
fuzz::pinweaver::Request request;
fuzz::pinweaver::ResetTree* reset_tree = request.mutable_reset_tree();
reset_tree->set_height(2);
reset_tree->set_bits_per_level(2);
assert(pinweaver_model.ApplyRequest(request, buffer_view) == EC_SUCCESS);
fuzz::pinweaver::InsertLeaf* insert_leaf = request.mutable_insert_leaf();
constexpr char delay_schedule[] = "\000\000\000\005\377\377\377\377";
insert_leaf->mutable_delay_schedule()->assign(
delay_schedule, delay_schedule + sizeof(delay_schedule));
assert(pinweaver_model.ApplyRequest(request, buffer_view) == EC_SUCCESS);
request.mutable_try_auth();
assert(pinweaver_model.ApplyRequest(request, buffer_view) == EC_SUCCESS);
request.mutable_get_log();
assert(pinweaver_model.ApplyRequest(request, buffer_view) == EC_SUCCESS);
request.mutable_log_replay();
assert(pinweaver_model.ApplyRequest(request, buffer_view) == EC_SUCCESS);
request.mutable_reset_auth();
assert(pinweaver_model.ApplyRequest(request, buffer_view) == EC_SUCCESS);
request.mutable_remove_leaf();
assert(pinweaver_model.ApplyRequest(request, buffer_view) == EC_SUCCESS);
return true;
}
DEFINE_CUSTOM_PROTO_MUTATOR_IMPL(false, fuzz::Cr50FuzzerInput)
DEFINE_CUSTOM_PROTO_CROSSOVER_IMPL(false, fuzz::Cr50FuzzerInput)
extern "C" int test_fuzz_one_input(const uint8_t* data, unsigned int size) {
static bool initialized = SelfTest();
assert(initialized);
fuzz::Cr50FuzzerInput input;
if (!LoadProtoInput(false, data, size, &input)) {
return 0;
}
InitializeFuzzerRun();
PinweaverModel pinweaver_model;
alignas(kBufferAlignment) uint8_t buffer[PW_MAX_MESSAGE_SIZE] = {};
fuzz::span<uint8_t> buffer_view(buffer, sizeof(buffer));
for (const fuzz::Cr50SubAction& action : input.sub_actions()) {
switch (action.sub_action_case()) {
case fuzz::Cr50SubAction::kRandomBytes:
fuzz::CopyWithPadding(action.random_bytes().value(), buffer_view, 0);
pinweaver_model.SendBuffer(buffer_view);
break;
case fuzz::Cr50SubAction::kPinweaver:
pinweaver_model.ApplyRequest(action.pinweaver(), buffer_view);
break;
case fuzz::Cr50SubAction::SUB_ACTION_NOT_SET:
break;
}
}
return 0;
}
|
