1 /* 2 * fuzzing driver 3 * 4 * Copyright Red Hat Inc., 2019 5 * 6 * Authors: 7 * Alexander Bulekov <alxndr@bu.edu> 8 * 9 * This work is licensed under the terms of the GNU GPL, version 2 or later. 10 * See the COPYING file in the top-level directory. 11 * 12 */ 13 14 #ifndef QTEST_FUZZ_H 15 #define QTEST_FUZZ_H 16 17 #include "qemu/units.h" 18 #include "qapi/error.h" 19 20 #include "tests/qtest/libqtest.h" 21 22 /** 23 * A libfuzzer fuzzing target 24 * 25 * The QEMU fuzzing binary is built with all available targets, each 26 * with a unique @name that can be specified on the command-line to 27 * select which target should run. 28 * 29 * A target must implement ->fuzz() to process a random input. If QEMU 30 * crashes in ->fuzz() then libfuzzer will record a failure. 31 * 32 * Fuzzing targets are registered with fuzz_add_target(): 33 * 34 * static const FuzzTarget fuzz_target = { 35 * .name = "my-device-fifo", 36 * .description = "Fuzz the FIFO buffer registers of my-device", 37 * ... 38 * }; 39 * 40 * static void register_fuzz_target(void) 41 * { 42 * fuzz_add_target(&fuzz_target); 43 * } 44 * fuzz_target_init(register_fuzz_target); 45 */ 46 typedef struct FuzzTarget { 47 const char *name; /* target identifier (passed to --fuzz-target=)*/ 48 const char *description; /* help text */ 49 50 51 /* 52 * Returns the arguments that are passed to qemu/softmmu init(). Freed by 53 * the caller. 54 */ 55 GString *(*get_init_cmdline)(struct FuzzTarget *); 56 57 /* 58 * will run once, prior to running qemu/softmmu init. 59 * eg: set up shared-memory for communication with the child-process 60 * Can be NULL 61 */ 62 void(*pre_vm_init)(void); 63 64 /* 65 * will run once, after QEMU has been initialized, prior to the fuzz-loop. 66 * eg: detect the memory map 67 * Can be NULL 68 */ 69 void(*pre_fuzz)(QTestState *); 70 71 /* 72 * accepts and executes an input from libfuzzer. this is repeatedly 73 * executed during the fuzzing loop. Its should handle setup, input 74 * execution and cleanup. 75 * Cannot be NULL 76 */ 77 void(*fuzz)(QTestState *, const unsigned char *, size_t); 78 79 /* 80 * The fuzzer can specify a "Custom Crossover" function for combining two 81 * inputs from the corpus. This function is sometimes called by libfuzzer 82 * when mutating inputs. 83 * 84 * data1: location of first input 85 * size1: length of first input 86 * data1: location of second input 87 * size1: length of second input 88 * out: where to place the resulting, mutated input 89 * max_out_size: the maximum length of the input that can be placed in out 90 * seed: the seed that should be used to make mutations deterministic, when 91 * needed 92 * 93 * See libfuzzer's LLVMFuzzerCustomCrossOver API for more info. 94 * 95 * Can be NULL 96 */ 97 size_t(*crossover)(const uint8_t *data1, size_t size1, 98 const uint8_t *data2, size_t size2, 99 uint8_t *out, size_t max_out_size, 100 unsigned int seed); 101 102 void *opaque; 103 } FuzzTarget; 104 105 void flush_events(QTestState *); 106 void fuzz_reset(QTestState *); 107 108 /* Use the QTest ASCII protocol or call address_space API directly?*/ 109 void fuzz_qtest_set_serialize(bool option); 110 111 /* 112 * makes a copy of *target and adds it to the target-list. 113 * i.e. fine to set up target on the caller's stack 114 */ 115 void fuzz_add_target(const FuzzTarget *target); 116 117 size_t LLVMFuzzerCustomCrossOver(const uint8_t *data1, size_t size1, 118 const uint8_t *data2, size_t size2, 119 uint8_t *out, size_t max_out_size, 120 unsigned int seed); 121 int LLVMFuzzerTestOneInput(const unsigned char *Data, size_t Size); 122 int LLVMFuzzerInitialize(int *argc, char ***argv, char ***envp); 123 124 #endif 125