1 // Copyright 2016 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef BASE_TEST_FUZZED_DATA_PROVIDER_H_ 6 #define BASE_TEST_FUZZED_DATA_PROVIDER_H_ 7 8 #include <stdint.h> 9 10 #include <string> 11 12 #include "base/base_export.h" 13 #include "base/macros.h" 14 #include "base/strings/string_piece.h" 15 16 namespace base { 17 18 // Utility class to break up fuzzer input for multiple consumers. Whenever run 19 // on the same input, provides the same output, as long as its methods are 20 // called in the same order, with the same arguments. 21 class FuzzedDataProvider { 22 public: 23 // |data| is an array of length |size| that the FuzzedDataProvider wraps to 24 // provide more granular access. |data| must outlive the FuzzedDataProvider. 25 FuzzedDataProvider(const uint8_t* data, size_t size); 26 ~FuzzedDataProvider(); 27 28 // Returns a std::string containing |num_bytes| of input data. If fewer than 29 // |num_bytes| of data remain, returns a shorter std::string containing all 30 // of the data that's left. 31 std::string ConsumeBytes(size_t num_bytes); 32 33 // Returns a std::string containing all remaining bytes of the input data. 34 std::string ConsumeRemainingBytes(); 35 36 // Returns a std::string of length from 0 to |max_length|. When it runs out of 37 // input data, returns what remains of the input. Designed to be more stable 38 // with respect to a fuzzer inserting characters than just picking a random 39 // length and then consuming that many bytes with ConsumeBytes(). 40 std::string ConsumeRandomLengthString(size_t max_length); 41 42 // Returns a number in the range [min, max] by consuming bytes from the input 43 // data. The value might not be uniformly distributed in the given range. If 44 // there's no input data left, always returns |min|. |min| must be less than 45 // or equal to |max|. 46 uint32_t ConsumeUint32InRange(uint32_t min, uint32_t max); 47 int ConsumeInt32InRange(int min, int max); 48 49 // Returns a bool, or false when no data remains. 50 bool ConsumeBool(); 51 52 // Returns a uint8_t from the input or 0 if nothing remains. This is 53 // equivalent to ConsumeUint32InRange(0, 0xFF). 54 uint8_t ConsumeUint8(); 55 56 // Returns a uint16_t from the input. If fewer than 2 bytes of data remain 57 // will fill the most significant bytes with 0. This is equivalent to 58 // ConsumeUint32InRange(0, 0xFFFF). 59 uint16_t ConsumeUint16(); 60 61 // Returns a value from |array|, consuming as many bytes as needed to do so. 62 // |array| must be a fixed-size array. Equivalent to 63 // array[ConsumeUint32InRange(sizeof(array)-1)]; 64 template <typename Type, size_t size> 65 Type PickValueInArray(Type (&array)[size]) { 66 return array[ConsumeUint32InRange(0, size - 1)]; 67 } 68 69 // Reports the remaining bytes available for fuzzed input. 70 size_t remaining_bytes() { return remaining_data_.length(); } 71 72 private: 73 StringPiece remaining_data_; 74 75 DISALLOW_COPY_AND_ASSIGN(FuzzedDataProvider); 76 }; 77 78 } // namespace base 79 80 #endif // BASE_TEST_FUZZED_DATA_PROVIDER_H_ 81
