Revert "[libFuzzer] Link libFuzzer's own interceptors when other compiler runtimes are not linked."
This causes binaries linked with this runtime to crash on startup if
dlsym uses any of the intercepted functions. (For example, that happens
when using tcmalloc as the allocator: dlsym attempts to allocate memory
with malloc, and tcmalloc uses strncmp within its implementation.)
Also revert dependent commit "[libFuzzer] Disable implicit builtin knowledge about memcmp-like functions when -fsanitize=fuzzer-no-link is given."
This reverts commit f78d9fceea736d431e9e3cbca291e3909e3aa46d and 12d1124c49beec0fb79d36944960e5bf0f236d4c.
GitOrigin-RevId: 8ef9e2bf355d05bc81d8b0fe1e5333eec59a0a91
diff --git a/FuzzerInterceptors.cpp b/FuzzerInterceptors.cpp
deleted file mode 100644
index cb55b4a..0000000
--- a/FuzzerInterceptors.cpp
+++ /dev/null
@@ -1,170 +0,0 @@
-//===-- 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
