+++ /dev/null
-//===-- FuzzerInterceptors.cpp --------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-// Intercept certain libc functions to aid fuzzing.
-// Linked only when other RTs that define their own interceptors are not linked.
-//===----------------------------------------------------------------------===//
-
-#include "FuzzerPlatform.h"
-
-#if LIBFUZZER_LINUX
-
-#define GET_CALLER_PC() __builtin_return_address(0)
-
-#define PTR_TO_REAL(x) real_##x
-#define REAL(x) __interception::PTR_TO_REAL(x)
-#define FUNC_TYPE(x) x##_type
-#define DEFINE_REAL(ret_type, func, ...) \
- typedef ret_type (*FUNC_TYPE(func))(__VA_ARGS__); \
- namespace __interception { \
- FUNC_TYPE(func) PTR_TO_REAL(func); \
- }
-
-#include <cassert>
-#include <cstdint>
-#include <dlfcn.h> // for dlsym()
-#include <sanitizer/common_interface_defs.h>
-
-static void *getFuncAddr(const char *name, uintptr_t wrapper_addr) {
- void *addr = dlsym(RTLD_NEXT, name);
- if (!addr) {
- // If the lookup using RTLD_NEXT failed, the sanitizer runtime library is
- // later in the library search order than the DSO that we are trying to
- // intercept, which means that we cannot intercept this function. We still
- // want the address of the real definition, though, so look it up using
- // RTLD_DEFAULT.
- addr = dlsym(RTLD_DEFAULT, name);
-
- // In case `name' is not loaded, dlsym ends up finding the actual wrapper.
- // We don't want to intercept the wrapper and have it point to itself.
- if (reinterpret_cast<uintptr_t>(addr) == wrapper_addr)
- addr = nullptr;
- }
- return addr;
-}
-
-static int FuzzerInited = 0;
-static bool FuzzerInitIsRunning;
-
-static void fuzzerInit();
-
-static void ensureFuzzerInited() {
- assert(!FuzzerInitIsRunning);
- if (!FuzzerInited) {
- fuzzerInit();
- }
-}
-
-extern "C" {
-
-DEFINE_REAL(int, memcmp, const void *, const void *, size_t)
-DEFINE_REAL(int, strncmp, const char *, const char *, size_t)
-DEFINE_REAL(int, strcmp, const char *, const char *)
-DEFINE_REAL(int, strncasecmp, const char *, const char *, size_t)
-DEFINE_REAL(int, strcasecmp, const char *, const char *)
-DEFINE_REAL(char *, strstr, const char *, const char *)
-DEFINE_REAL(char *, strcasestr, const char *, const char *)
-DEFINE_REAL(void *, memmem, const void *, size_t, const void *, size_t)
-
-ATTRIBUTE_INTERFACE int memcmp(const void *s1, const void *s2, size_t n) {
- ensureFuzzerInited();
- int result = REAL(memcmp)(s1, s2, n);
- __sanitizer_weak_hook_memcmp(GET_CALLER_PC(), s1, s2, n, result);
-
- return result;
-}
-
-ATTRIBUTE_INTERFACE int strncmp(const char *s1, const char *s2, size_t n) {
- ensureFuzzerInited();
- int result = REAL(strncmp)(s1, s2, n);
- __sanitizer_weak_hook_strncmp(GET_CALLER_PC(), s1, s2, n, result);
-
- return result;
-}
-
-ATTRIBUTE_INTERFACE int strcmp(const char *s1, const char *s2) {
- ensureFuzzerInited();
- int result = REAL(strcmp)(s1, s2);
- __sanitizer_weak_hook_strcmp(GET_CALLER_PC(), s1, s2, result);
-
- return result;
-}
-
-ATTRIBUTE_INTERFACE int strncasecmp(const char *s1, const char *s2, size_t n) {
- ensureFuzzerInited();
- int result = REAL(strncasecmp)(s1, s2, n);
- __sanitizer_weak_hook_strncasecmp(GET_CALLER_PC(), s1, s2, n, result);
-
- return result;
-}
-
-ATTRIBUTE_INTERFACE int strcasecmp(const char *s1, const char *s2) {
- ensureFuzzerInited();
- int result = REAL(strcasecmp)(s1, s2);
- __sanitizer_weak_hook_strcasecmp(GET_CALLER_PC(), s1, s2, result);
-
- return result;
-}
-
-ATTRIBUTE_INTERFACE char *strstr(const char *s1, const char *s2) {
- ensureFuzzerInited();
- char *result = REAL(strstr)(s1, s2);
- __sanitizer_weak_hook_strstr(GET_CALLER_PC(), s1, s2, result);
-
- return result;
-}
-
-ATTRIBUTE_INTERFACE char *strcasestr(const char *s1, const char *s2) {
- ensureFuzzerInited();
- char *result = REAL(strcasestr)(s1, s2);
- __sanitizer_weak_hook_strcasestr(GET_CALLER_PC(), s1, s2, result);
-
- return result;
-}
-
-ATTRIBUTE_INTERFACE
-void *memmem(const void *s1, size_t len1, const void *s2, size_t len2) {
- ensureFuzzerInited();
- void *result = REAL(memmem)(s1, len1, s2, len2);
- __sanitizer_weak_hook_memmem(GET_CALLER_PC(), s1, len1, s2, len2, result);
-
- return result;
-}
-
-__attribute__((section(".preinit_array"),
- used)) static void (*__local_fuzzer_preinit)(void) = fuzzerInit;
-
-} // extern "C"
-
-static void fuzzerInit() {
- assert(!FuzzerInitIsRunning);
- if (FuzzerInited)
- return;
- FuzzerInitIsRunning = true;
-
- REAL(memcmp) = reinterpret_cast<memcmp_type>(
- getFuncAddr("memcmp", reinterpret_cast<uintptr_t>(&memcmp)));
- REAL(strncmp) = reinterpret_cast<strncmp_type>(
- getFuncAddr("strncmp", reinterpret_cast<uintptr_t>(&strncmp)));
- REAL(strcmp) = reinterpret_cast<strcmp_type>(
- getFuncAddr("strcmp", reinterpret_cast<uintptr_t>(&strcmp)));
- REAL(strncasecmp) = reinterpret_cast<strncasecmp_type>(
- getFuncAddr("strncasecmp", reinterpret_cast<uintptr_t>(&strncasecmp)));
- REAL(strcasecmp) = reinterpret_cast<strcasecmp_type>(
- getFuncAddr("strcasecmp", reinterpret_cast<uintptr_t>(&strcasecmp)));
- REAL(strstr) = reinterpret_cast<strstr_type>(
- getFuncAddr("strstr", reinterpret_cast<uintptr_t>(&strstr)));
- REAL(strcasestr) = reinterpret_cast<strcasestr_type>(
- getFuncAddr("strcasestr", reinterpret_cast<uintptr_t>(&strcasestr)));
- REAL(memmem) = reinterpret_cast<memmem_type>(
- getFuncAddr("memmem", reinterpret_cast<uintptr_t>(&memmem)));
-
- FuzzerInitIsRunning = false;
- FuzzerInited = 1;
-}
-
-#endif
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