| // Copyright 2016 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "net/base/fuzzed_data_provider.h" |
| |
| #include <algorithm> |
| #include <limits> |
| |
| #include "base/logging.h" |
| |
| namespace net { |
| |
| FuzzedDataProvider::FuzzedDataProvider(const uint8_t* data, size_t size) |
| : remaining_data_(reinterpret_cast<const char*>(data), size) {} |
| |
| FuzzedDataProvider::~FuzzedDataProvider() {} |
| |
| base::StringPiece FuzzedDataProvider::ConsumeBytes(size_t num_bytes) { |
| num_bytes = std::min(num_bytes, remaining_data_.length()); |
| base::StringPiece result(remaining_data_.data(), num_bytes); |
| remaining_data_ = remaining_data_.substr(num_bytes); |
| return result; |
| } |
| |
| base::StringPiece FuzzedDataProvider::ConsumeRemainingBytes() { |
| return ConsumeBytes(remaining_data_.length()); |
| } |
| |
| uint32_t FuzzedDataProvider::ConsumeUint32InRange(uint32_t min, uint32_t max) { |
| CHECK_LE(min, max); |
| |
| uint32_t range = max - min; |
| uint32_t offset = 0; |
| uint32_t result = 0; |
| |
| while ((range >> offset) > 0 && !remaining_data_.empty()) { |
| // Pull bytes off the end of the seed data. Experimentally, this seems to |
| // allow the fuzzer to more easily explore the input space. This makes |
| // sense, since it works by modifying inputs that caused new code to run, |
| // and this data is often used to encode length of data read by |
| // ConsumeBytes. Separating out read lengths makes it easier modify the |
| // contents of the data that is actually read. |
| uint8_t next_byte = remaining_data_.back(); |
| remaining_data_.remove_suffix(1); |
| result = (result << 8) | next_byte; |
| offset += 8; |
| } |
| |
| // Avoid division by 0, in the case |range + 1| results in overflow. |
| if (range == std::numeric_limits<uint32_t>::max()) |
| return result; |
| |
| return min + result % (range + 1); |
| } |
| |
| int FuzzedDataProvider::ConsumeInt32InRange(int min, int max) { |
| CHECK_LE(min, max); |
| |
| uint32_t range = max - min; |
| return min + ConsumeUint32InRange(0, range); |
| } |
| |
| bool FuzzedDataProvider::ConsumeBool() { |
| return (ConsumeUint8() & 0x01) == 0x01; |
| } |
| |
| uint8_t FuzzedDataProvider::ConsumeUint8() { |
| return ConsumeUint32InRange(0, 0xFF); |
| } |
| |
| uint16_t FuzzedDataProvider::ConsumeUint16() { |
| return ConsumeUint32InRange(0, 0xFFFF); |
| } |
| |
| } // namespace net |