1//===-- dfsan_interface.h -------------------------------------------------===// 2// 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4// See https://llvm.org/LICENSE.txt for license information. 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6// 7//===----------------------------------------------------------------------===// 8// 9// This file is a part of DataFlowSanitizer. 10// 11// Public interface header. 12//===----------------------------------------------------------------------===// 13#ifndef DFSAN_INTERFACE_H 14#define DFSAN_INTERFACE_H 15 16#include <stddef.h> 17#include <stdint.h> 18#include <sanitizer/common_interface_defs.h> 19 20#ifdef __cplusplus 21extern "C" { 22#endif 23 24typedef uint16_t dfsan_label; 25 26/// Stores information associated with a specific label identifier. A label 27/// may be a base label created using dfsan_create_label, with associated 28/// text description and user data, or an automatically created union label, 29/// which represents the union of two label identifiers (which may themselves 30/// be base or union labels). 31struct dfsan_label_info { 32 // Fields for union labels, set to 0 for base labels. 33 dfsan_label l1; 34 dfsan_label l2; 35 36 // Fields for base labels. 37 const char *desc; 38 void *userdata; 39}; 40 41/// Signature of the callback argument to dfsan_set_write_callback(). 42typedef void (*dfsan_write_callback_t)(int fd, const void *buf, size_t count); 43 44/// Computes the union of \c l1 and \c l2, possibly creating a union label in 45/// the process. 46dfsan_label dfsan_union(dfsan_label l1, dfsan_label l2); 47 48/// Creates and returns a base label with the given description and user data. 49dfsan_label dfsan_create_label(const char *desc, void *userdata); 50 51/// Sets the label for each address in [addr,addr+size) to \c label. 52void dfsan_set_label(dfsan_label label, void *addr, size_t size); 53 54/// Sets the label for each address in [addr,addr+size) to the union of the 55/// current label for that address and \c label. 56void dfsan_add_label(dfsan_label label, void *addr, size_t size); 57 58/// Retrieves the label associated with the given data. 59/// 60/// The type of 'data' is arbitrary. The function accepts a value of any type, 61/// which can be truncated or extended (implicitly or explicitly) as necessary. 62/// The truncation/extension operations will preserve the label of the original 63/// value. 64dfsan_label dfsan_get_label(long data); 65 66/// Retrieves the label associated with the data at the given address. 67dfsan_label dfsan_read_label(const void *addr, size_t size); 68 69/// Retrieves a pointer to the dfsan_label_info struct for the given label. 70const struct dfsan_label_info *dfsan_get_label_info(dfsan_label label); 71 72/// Returns whether the given label label contains the label elem. 73int dfsan_has_label(dfsan_label label, dfsan_label elem); 74 75/// If the given label label contains a label with the description desc, returns 76/// that label, else returns 0. 77dfsan_label dfsan_has_label_with_desc(dfsan_label label, const char *desc); 78 79/// Returns the number of labels allocated. 80size_t dfsan_get_label_count(void); 81 82/// Flushes the DFSan shadow, i.e. forgets about all labels currently associated 83/// with the application memory. Will work only if there are no other 84/// threads executing DFSan-instrumented code concurrently. 85/// Use this call to start over the taint tracking within the same procces. 86void dfsan_flush(void); 87 88/// Sets a callback to be invoked on calls to write(). The callback is invoked 89/// before the write is done. The write is not guaranteed to succeed when the 90/// callback executes. Pass in NULL to remove any callback. 91void dfsan_set_write_callback(dfsan_write_callback_t labeled_write_callback); 92 93/// Writes the labels currently used by the program to the given file 94/// descriptor. The lines of the output have the following format: 95/// 96/// <label> <parent label 1> <parent label 2> <label description if any> 97void dfsan_dump_labels(int fd); 98 99/// Interceptor hooks. 100/// Whenever a dfsan's custom function is called the corresponding 101/// hook is called it non-zero. The hooks should be defined by the user. 102/// The primary use case is taint-guided fuzzing, where the fuzzer 103/// needs to see the parameters of the function and the labels. 104/// FIXME: implement more hooks. 105void dfsan_weak_hook_memcmp(void *caller_pc, const void *s1, const void *s2, 106 size_t n, dfsan_label s1_label, 107 dfsan_label s2_label, dfsan_label n_label); 108void dfsan_weak_hook_strncmp(void *caller_pc, const char *s1, const char *s2, 109 size_t n, dfsan_label s1_label, 110 dfsan_label s2_label, dfsan_label n_label); 111#ifdef __cplusplus 112} // extern "C" 113 114template <typename T> 115void dfsan_set_label(dfsan_label label, T &data) { // NOLINT 116 dfsan_set_label(label, (void *)&data, sizeof(T)); 117} 118 119#endif 120 121#endif // DFSAN_INTERFACE_H 122