1 /*
2 * Copyright (C) 2020 The Android Open Sourete 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 #define LOG_TAG "trusty-fuzz-counters"
18
19 #include <trusty/fuzz/counters.h>
20
21 #include <android-base/logging.h>
22 #include <assert.h>
23 #include <log/log.h>
24 #include <string.h>
25 #include <trusty/coverage/coverage.h>
26 #include <trusty/coverage/tipc.h>
27
28 using android::base::ErrnoError;
29 using android::base::Error;
30 using android::base::Result;
31
32 /*
33 * We don't know how many counters the coverage record will contain. So, eyeball
34 * the size of this section.
35 */
36 static const size_t kMaxNumCounters = 0x10000;
37 __attribute__((section("__libfuzzer_extra_counters"))) volatile uint8_t counters[kMaxNumCounters];
38
39 namespace android {
40 namespace trusty {
41 namespace fuzz {
42
ExtraCounters(coverage::CoverageRecord * record)43 ExtraCounters::ExtraCounters(coverage::CoverageRecord* record) : record_(record) {
44 if (!record_->IsOpen()) {
45 return;
46 }
47
48 volatile uint8_t* begin = NULL;
49 volatile uint8_t* end = NULL;
50 record_->GetRawCounts(&begin, &end);
51 assert(end - begin <= sizeof(counters));
52 }
53
~ExtraCounters()54 ExtraCounters::~ExtraCounters() {
55 if (!record_->IsOpen()) {
56 return;
57 }
58
59 Flush();
60 }
61
Reset()62 void ExtraCounters::Reset() {
63 if (!record_->IsOpen()) {
64 return;
65 }
66 record_->ResetCounts();
67 memset_explicit(const_cast<uint8_t*>(counters), 0, sizeof(counters));
68 }
69
Flush()70 void ExtraCounters::Flush() {
71 volatile uint8_t* begin = NULL;
72 volatile uint8_t* end = NULL;
73
74 record_->GetRawCounts(&begin, &end);
75 if (!begin || !end) {
76 ALOGE("Could not get raw counts from coverage record\n");
77 return;
78 }
79
80 size_t num_counters = end - begin;
81 if (num_counters > kMaxNumCounters) {
82 ALOGE("Too many counters (%zu) to fit in the extra counters section!\n", num_counters);
83 num_counters = kMaxNumCounters;
84 }
85 for (size_t i = 0; i < num_counters; i++) {
86 *(counters + i) = *(begin + i);
87 }
88 }
89
90 } // namespace fuzz
91 } // namespace trusty
92 } // namespace android
93