| /* |
| american fuzzy lop++ - wrapper for GCC and clang |
| ------------------------------------------------ |
| |
| Originally written by Michal Zalewski |
| |
| Now maintained by Marc Heuse <mh@mh-sec.de>, |
| Heiko Eißfeldt <heiko.eissfeldt@hexco.de> and |
| Andrea Fioraldi <andreafioraldi@gmail.com> |
| |
| Copyright 2016, 2017 Google Inc. All rights reserved. |
| Copyright 2019-2020 AFLplusplus Project. All rights reserved. |
| |
| Licensed under the Apache License, Version 2.0 (the "License"); |
| you may not use this file except in compliance with the License. |
| You may obtain a copy of the License at: |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| This program is a drop-in replacement for GCC or clang. The most common way |
| of using it is to pass the path to afl-gcc or afl-clang via CC when invoking |
| ./configure. |
| |
| (Of course, use CXX and point it to afl-g++ / afl-clang++ for C++ code.) |
| |
| The wrapper needs to know the path to afl-as (renamed to 'as'). The default |
| is /usr/local/lib/afl/. A convenient way to specify alternative directories |
| would be to set AFL_PATH. |
| |
| If AFL_HARDEN is set, the wrapper will compile the target app with various |
| hardening options that may help detect memory management issues more |
| reliably. You can also specify AFL_USE_ASAN to enable ASAN. |
| |
| If you want to call a non-default compiler as a next step of the chain, |
| specify its location via AFL_CC or AFL_CXX. |
| |
| */ |
| |
| #define AFL_MAIN |
| |
| #include "config.h" |
| #include "types.h" |
| #include "debug.h" |
| #include "alloc-inl.h" |
| |
| #include <stdio.h> |
| #include <unistd.h> |
| #include <stdlib.h> |
| #include <string.h> |
| |
| static u8 * as_path; /* Path to the AFL 'as' wrapper */ |
| static u8 **cc_params; /* Parameters passed to the real CC */ |
| static u32 cc_par_cnt = 1; /* Param count, including argv0 */ |
| static u8 be_quiet, /* Quiet mode */ |
| clang_mode; /* Invoked as afl-clang*? */ |
| |
| /* Try to find our "fake" GNU assembler in AFL_PATH or at the location derived |
| from argv[0]. If that fails, abort. */ |
| |
| static void find_as(u8 *argv0) { |
| |
| u8 *afl_path = getenv("AFL_PATH"); |
| u8 *slash, *tmp; |
| |
| if (afl_path) { |
| |
| tmp = alloc_printf("%s/as", afl_path); |
| |
| if (!access(tmp, X_OK)) { |
| |
| as_path = afl_path; |
| ck_free(tmp); |
| return; |
| |
| } |
| |
| ck_free(tmp); |
| |
| } |
| |
| slash = strrchr(argv0, '/'); |
| |
| if (slash) { |
| |
| u8 *dir; |
| |
| *slash = 0; |
| dir = ck_strdup(argv0); |
| *slash = '/'; |
| |
| tmp = alloc_printf("%s/afl-as", dir); |
| |
| if (!access(tmp, X_OK)) { |
| |
| as_path = dir; |
| ck_free(tmp); |
| return; |
| |
| } |
| |
| ck_free(tmp); |
| ck_free(dir); |
| |
| } |
| |
| if (!access(AFL_PATH "/as", X_OK)) { |
| |
| as_path = AFL_PATH; |
| return; |
| |
| } |
| |
| FATAL("Unable to find AFL wrapper binary for 'as'. Please set AFL_PATH"); |
| |
| } |
| |
| /* Copy argv to cc_params, making the necessary edits. */ |
| |
| static void edit_params(u32 argc, char **argv) { |
| |
| u8 fortify_set = 0, asan_set = 0; |
| u8 *name; |
| |
| #if defined(__FreeBSD__) && defined(WORD_SIZE_64) |
| u8 m32_set = 0; |
| #endif |
| |
| cc_params = ck_alloc((argc + 128) * sizeof(u8 *)); |
| |
| name = strrchr(argv[0], '/'); |
| if (!name) { |
| |
| name = argv[0]; |
| |
| /* This should never happen but fixes a scan-build warning */ |
| if (!name) { FATAL("Empty argv set"); } |
| |
| } else { |
| |
| ++name; |
| |
| } |
| |
| if (!strncmp(name, "afl-clang", 9)) { |
| |
| clang_mode = 1; |
| |
| setenv(CLANG_ENV_VAR, "1", 1); |
| |
| if (!strcmp(name, "afl-clang++")) { |
| |
| u8 *alt_cxx = getenv("AFL_CXX"); |
| cc_params[0] = alt_cxx && *alt_cxx ? alt_cxx : (u8 *)"clang++"; |
| |
| } else if (!strcmp(name, "afl-clang")) { |
| |
| u8 *alt_cc = getenv("AFL_CC"); |
| cc_params[0] = alt_cc && *alt_cc ? alt_cc : (u8 *)"clang"; |
| |
| } else { |
| |
| fprintf(stderr, "Name of the binary: %s\n", argv[0]); |
| FATAL("Name of the binary is not a known name, expected afl-clang(++)"); |
| |
| } |
| |
| } else { |
| |
| /* With GCJ and Eclipse installed, you can actually compile Java! The |
| instrumentation will work (amazingly). Alas, unhandled exceptions do |
| not call abort(), so afl-fuzz would need to be modified to equate |
| non-zero exit codes with crash conditions when working with Java |
| binaries. Meh. */ |
| |
| #ifdef __APPLE__ |
| |
| if (!strcmp(name, "afl-g++")) { |
| |
| cc_params[0] = getenv("AFL_CXX"); |
| |
| } else if (!strcmp(name, "afl-gcj")) { |
| |
| cc_params[0] = getenv("AFL_GCJ"); |
| |
| } else if (!strcmp(name, "afl-gcc")) { |
| |
| cc_params[0] = getenv("AFL_CC"); |
| |
| } else { |
| |
| fprintf(stderr, "Name of the binary: %s\n", argv[0]); |
| FATAL("Name of the binary is not a known name, expected afl-gcc/g++/gcj"); |
| |
| } |
| |
| if (!cc_params[0]) { |
| |
| SAYF("\n" cLRD "[-] " cRST |
| "On Apple systems, 'gcc' is usually just a wrapper for clang. " |
| "Please use the\n" |
| " 'afl-clang' utility instead of 'afl-gcc'. If you really have " |
| "GCC installed,\n" |
| " set AFL_CC or AFL_CXX to specify the correct path to that " |
| "compiler.\n"); |
| |
| FATAL("AFL_CC or AFL_CXX required on MacOS X"); |
| |
| } |
| |
| #else |
| |
| if (!strcmp(name, "afl-g++")) { |
| |
| u8 *alt_cxx = getenv("AFL_CXX"); |
| cc_params[0] = alt_cxx && *alt_cxx ? alt_cxx : (u8 *)"g++"; |
| |
| } else if (!strcmp(name, "afl-gcj")) { |
| |
| u8 *alt_cc = getenv("AFL_GCJ"); |
| cc_params[0] = alt_cc && *alt_cc ? alt_cc : (u8 *)"gcj"; |
| |
| } else if (!strcmp(name, "afl-gcc")) { |
| |
| u8 *alt_cc = getenv("AFL_CC"); |
| cc_params[0] = alt_cc && *alt_cc ? alt_cc : (u8 *)"gcc"; |
| |
| } else { |
| |
| fprintf(stderr, "Name of the binary: %s\n", argv[0]); |
| FATAL("Name of the binary is not a known name, expected afl-gcc/g++/gcj"); |
| |
| } |
| |
| #endif /* __APPLE__ */ |
| |
| } |
| |
| while (--argc) { |
| |
| u8 *cur = *(++argv); |
| |
| if (!strncmp(cur, "-B", 2)) { |
| |
| if (!be_quiet) { WARNF("-B is already set, overriding"); } |
| |
| if (!cur[2] && argc > 1) { |
| |
| argc--; |
| argv++; |
| |
| } |
| |
| continue; |
| |
| } |
| |
| if (!strcmp(cur, "-integrated-as")) { continue; } |
| |
| if (!strcmp(cur, "-pipe")) { continue; } |
| |
| #if defined(__FreeBSD__) && defined(WORD_SIZE_64) |
| if (!strcmp(cur, "-m32")) m32_set = 1; |
| #endif |
| |
| if (!strcmp(cur, "-fsanitize=address") || |
| !strcmp(cur, "-fsanitize=memory")) { |
| |
| asan_set = 1; |
| |
| } |
| |
| if (strstr(cur, "FORTIFY_SOURCE")) { fortify_set = 1; } |
| |
| cc_params[cc_par_cnt++] = cur; |
| |
| } |
| |
| cc_params[cc_par_cnt++] = "-B"; |
| cc_params[cc_par_cnt++] = as_path; |
| |
| if (clang_mode) { cc_params[cc_par_cnt++] = "-no-integrated-as"; } |
| |
| if (getenv("AFL_HARDEN")) { |
| |
| cc_params[cc_par_cnt++] = "-fstack-protector-all"; |
| |
| if (!fortify_set) { cc_params[cc_par_cnt++] = "-D_FORTIFY_SOURCE=2"; } |
| |
| } |
| |
| if (asan_set) { |
| |
| /* Pass this on to afl-as to adjust map density. */ |
| |
| setenv("AFL_USE_ASAN", "1", 1); |
| |
| } else if (getenv("AFL_USE_ASAN")) { |
| |
| if (getenv("AFL_USE_MSAN")) { |
| |
| FATAL("ASAN and MSAN are mutually exclusive"); |
| |
| } |
| |
| if (getenv("AFL_HARDEN")) { |
| |
| FATAL("ASAN and AFL_HARDEN are mutually exclusive"); |
| |
| } |
| |
| cc_params[cc_par_cnt++] = "-U_FORTIFY_SOURCE"; |
| cc_params[cc_par_cnt++] = "-fsanitize=address"; |
| |
| } else if (getenv("AFL_USE_MSAN")) { |
| |
| if (getenv("AFL_USE_ASAN")) { |
| |
| FATAL("ASAN and MSAN are mutually exclusive"); |
| |
| } |
| |
| if (getenv("AFL_HARDEN")) { |
| |
| FATAL("MSAN and AFL_HARDEN are mutually exclusive"); |
| |
| } |
| |
| cc_params[cc_par_cnt++] = "-U_FORTIFY_SOURCE"; |
| cc_params[cc_par_cnt++] = "-fsanitize=memory"; |
| |
| } |
| |
| if (getenv("AFL_USE_UBSAN")) { |
| |
| cc_params[cc_par_cnt++] = "-fsanitize=undefined"; |
| cc_params[cc_par_cnt++] = "-fsanitize-undefined-trap-on-error"; |
| cc_params[cc_par_cnt++] = "-fno-sanitize-recover=all"; |
| |
| } |
| |
| #if defined(USEMMAP) && !defined(__HAIKU__) |
| cc_params[cc_par_cnt++] = "-lrt"; |
| #endif |
| |
| if (!getenv("AFL_DONT_OPTIMIZE")) { |
| |
| #if defined(__FreeBSD__) && defined(WORD_SIZE_64) |
| |
| /* On 64-bit FreeBSD systems, clang -g -m32 is broken, but -m32 itself |
| works OK. This has nothing to do with us, but let's avoid triggering |
| that bug. */ |
| |
| if (!clang_mode || !m32_set) cc_params[cc_par_cnt++] = "-g"; |
| |
| #else |
| |
| cc_params[cc_par_cnt++] = "-g"; |
| |
| #endif |
| |
| cc_params[cc_par_cnt++] = "-O3"; |
| cc_params[cc_par_cnt++] = "-funroll-loops"; |
| |
| /* Two indicators that you're building for fuzzing; one of them is |
| AFL-specific, the other is shared with libfuzzer. */ |
| |
| cc_params[cc_par_cnt++] = "-D__AFL_COMPILER=1"; |
| cc_params[cc_par_cnt++] = "-DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION=1"; |
| |
| } |
| |
| if (getenv("AFL_NO_BUILTIN")) { |
| |
| cc_params[cc_par_cnt++] = "-fno-builtin-strcmp"; |
| cc_params[cc_par_cnt++] = "-fno-builtin-strncmp"; |
| cc_params[cc_par_cnt++] = "-fno-builtin-strcasecmp"; |
| cc_params[cc_par_cnt++] = "-fno-builtin-strncasecmp"; |
| cc_params[cc_par_cnt++] = "-fno-builtin-memcmp"; |
| cc_params[cc_par_cnt++] = "-fno-builtin-bcmp"; |
| cc_params[cc_par_cnt++] = "-fno-builtin-strstr"; |
| cc_params[cc_par_cnt++] = "-fno-builtin-strcasestr"; |
| |
| } |
| |
| cc_params[cc_par_cnt] = NULL; |
| |
| } |
| |
| /* Main entry point */ |
| |
| int main(int argc, char **argv) { |
| |
| char *env_info = |
| "Environment variables used by afl-gcc:\n" |
| "AFL_CC: path to the C compiler to use\n" |
| "AFL_CXX: path to the C++ compiler to use\n" |
| "AFL_GCJ: path to the java compiler to use\n" |
| "AFL_PATH: path to the instrumenting assembler\n" |
| "AFL_DONT_OPTIMIZE: disable optimization instead of -O3\n" |
| "AFL_NO_BUILTIN: compile for use with libtokencap.so\n" |
| "AFL_QUIET: suppress verbose output\n" |
| "AFL_CAL_FAST: speed up the initial calibration\n" |
| "AFL_HARDEN: adds code hardening to catch memory bugs\n" |
| "AFL_USE_ASAN: activate address sanitizer\n" |
| "AFL_USE_MSAN: activate memory sanitizer\n" |
| "AFL_USE_UBSAN: activate undefined behaviour sanitizer\n" |
| |
| "\nEnvironment variables used by afl-as (called by afl-gcc):\n" |
| "AFL_AS: path to the assembler to use\n" |
| "TMPDIR: set the directory for temporary files of afl-as\n" |
| "TEMP: fall back path to directory for temporary files\n" |
| "TMP: fall back path to directory for temporary files\n" |
| "AFL_INST_RATIO: percentage of branches to instrument\n" |
| "AFL_QUIET: suppress verbose output\n" |
| "AFL_KEEP_ASSEMBLY: leave instrumented assembly files\n" |
| "AFL_AS_FORCE_INSTRUMENT: force instrumentation for asm sources\n"; |
| |
| if (argc == 2 && strcmp(argv[1], "-h") == 0) { |
| |
| printf("afl-cc" VERSION " by Michal Zalewski\n\n"); |
| printf("%s \n\n", argv[0]); |
| printf("afl-gcc has no command line options\n\n%s\n", env_info); |
| printf( |
| "NOTE: afl-gcc is deprecated, llvm_mode is much faster and has more " |
| "options\n"); |
| return -1; |
| |
| } |
| |
| if ((isatty(2) && !getenv("AFL_QUIET")) || getenv("AFL_DEBUG") != NULL) { |
| |
| SAYF(cCYA "afl-cc" VERSION cRST " by Michal Zalewski\n"); |
| SAYF(cYEL "[!] " cBRI "NOTE: " cRST |
| "afl-gcc is deprecated, llvm_mode is much faster and has more " |
| "options\n"); |
| |
| } else { |
| |
| be_quiet = 1; |
| |
| } |
| |
| if (argc < 2) { |
| |
| SAYF( |
| "\n" |
| "This is a helper application for afl-fuzz. It serves as a drop-in " |
| "replacement\n" |
| "for gcc or clang, letting you recompile third-party code with the " |
| "required\n" |
| "runtime instrumentation. A common use pattern would be one of the " |
| "following:\n\n" |
| |
| " CC=%s/afl-gcc ./configure\n" |
| " CXX=%s/afl-g++ ./configure\n\n%s" |
| |
| , |
| BIN_PATH, BIN_PATH, env_info); |
| |
| exit(1); |
| |
| } |
| |
| u8 *ptr; |
| if (!be_quiet && |
| ((ptr = getenv("AFL_MAP_SIZE")) || (ptr = getenv("AFL_MAPSIZE")))) { |
| |
| u32 map_size = atoi(ptr); |
| if (map_size != MAP_SIZE) { |
| |
| WARNF("AFL_MAP_SIZE is not supported by afl-gcc"); |
| |
| } |
| |
| } |
| |
| find_as(argv[0]); |
| |
| edit_params(argc, argv); |
| |
| execvp(cc_params[0], (char **)cc_params); |
| |
| FATAL("Oops, failed to execute '%s' - check your PATH", cc_params[0]); |
| |
| return 0; |
| |
| } |
| |
