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 <FuzzerDefs.h>
20 
21 #include <trusty/fuzz/counters.h>
22 
23 #include <android-base/logging.h>
24 #include <log/log.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 = 0x8000;
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     assert(fuzzer::ExtraCountersBegin());
49     assert(fuzzer::ExtraCountersEnd());
50 
51     volatile uint8_t* begin = NULL;
52     volatile uint8_t* end = NULL;
53     record_->GetRawCounts(&begin, &end);
54     assert(end - begin <= sizeof(counters));
55 }
56 
~ExtraCounters()57 ExtraCounters::~ExtraCounters() {
58     if (!record_->IsOpen()) {
59         return;
60     }
61 
62     Flush();
63 }
64 
Reset()65 void ExtraCounters::Reset() {
66     if (!record_->IsOpen()) {
67         return;
68     }
69 
70     record_->ResetCounts();
71     fuzzer::ClearExtraCounters();
72 }
73 
Flush()74 void ExtraCounters::Flush() {
75     volatile uint8_t* begin = NULL;
76     volatile uint8_t* end = NULL;
77 
78     record_->GetRawCounts(&begin, &end);
79     if (!begin || !end) {
80         ALOGE("Could not get raw counts from coverage record\n");
81         return;
82     }
83 
84     size_t num_counters = end - begin;
85     if (num_counters > kMaxNumCounters) {
86         ALOGE("Too many counters (%zu) to fit in the extra counters section!\n", num_counters);
87         num_counters = kMaxNumCounters;
88     }
89     for (size_t i = 0; i < num_counters; i++) {
90         *(counters + i) = *(begin + i);
91     }
92 }
93 
94 }  // namespace fuzz
95 }  // namespace trusty
96 }  // namespace android
97