AFLplusplus/src/afl-common.c
2020-03-20 17:10:44 +01:00

396 lines
9.7 KiB
C

/*
american fuzzy lop++ - common routines
--------------------------------------
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
Gather some functions common to multiple executables
- detect_file_args
*/
#include <stdlib.h>
#include <stdio.h>
#include <strings.h>
#include "debug.h"
#include "alloc-inl.h"
#include "envs.h"
/* Detect @@ in args. */
#ifndef __glibc__
#include <unistd.h>
#endif
#include <limits.h>
extern u8 be_quiet;
char * afl_environment_variables[] = {
"AFL_ALIGNED_ALLOC", "AFL_ALLOW_TMP", "AFL_ANALYZE_HEX", "AFL_AS",
"AFL_AUTORESUME", "AFL_AS_FORCE_INSTRUMENT", "AFL_BENCH_JUST_ONE",
"AFL_BENCH_UNTIL_CRASH", "AFL_CAL_FAST", "AFL_CC", "AFL_CMIN_ALLOW_ANY",
"AFL_CMIN_CRASHES_ONLY", "AFL_CODE_END", "AFL_CODE_START",
"AFL_COMPCOV_BINNAME", "AFL_COMPCOV_LEVEL", "AFL_CUSTOM_MUTATOR_LIBRARY",
"AFL_CUSTOM_MUTATOR_ONLY", "AFL_CXX", "AFL_DEBUG", "AFL_DEBUG_CHILD_OUTPUT",
//"AFL_DEFER_FORKSRV", // not implemented anymore, so warn additionally
"AFL_DISABLE_TRIM", "AFL_DONT_OPTIMIZE", "AFL_DUMB_FORKSRV",
"AFL_ENTRYPOINT", "AFL_EXIT_WHEN_DONE", "AFL_FAST_CAL", "AFL_FORCE_UI",
"AFL_GCC_WHITELIST", "AFL_GCJ", "AFL_HANG_TMOUT", "AFL_HARDEN",
"AFL_I_DONT_CARE_ABOUT_MISSING_CRASHES", "AFL_IMPORT_FIRST",
"AFL_INST_LIBS", "AFL_INST_RATIO", "AFL_KEEP_TRACES", "AFL_KEEP_ASSEMBLY",
"AFL_LD_HARD_FAIL", "AFL_LD_LIMIT_MB", "AFL_LD_NO_CALLOC_OVER",
"AFL_LD_PRELOAD", "AFL_LD_VERBOSE", "AFL_LLVM_CMPLOG", "AFL_LLVM_INSTRIM",
"AFL_LLVM_INSTRIM_LOOPHEAD", "AFL_LLVM_INSTRIM_SKIPSINGLEBLOCK",
"AFL_LLVM_LAF_SPLIT_COMPARES", "AFL_LLVM_LAF_SPLIT_COMPARES_BITW",
"AFL_LLVM_LAF_SPLIT_FLOATS", "AFL_LLVM_LAF_SPLIT_SWITCHES",
"AFL_LLVM_LAF_TRANSFORM_COMPARES", "AFL_LLVM_NGRAM_SIZE", "AFL_NGRAM_SIZE",
"AFL_LLVM_NOT_ZERO", "AFL_LLVM_WHITELIST", "AFL_NO_AFFINITY",
"AFL_LLVM_LTO_STARTID", "AFL_LLVM_LTO_DONTWRITEID", "AFL_NO_ARITH",
"AFL_NO_BUILTIN", "AFL_NO_CPU_RED", "AFL_NO_FORKSRV", "AFL_NO_UI",
"AFL_NO_X86", // not really an env but we dont want to warn on it
"AFL_PATH", "AFL_PERFORMANCE_FILE",
//"AFL_PERSISTENT", // not implemented anymore, so warn additionally
"AFL_POST_LIBRARY", "AFL_PRELOAD", "AFL_PYTHON_MODULE", "AFL_QEMU_COMPCOV",
"AFL_QEMU_COMPCOV_DEBUG", "AFL_QEMU_DEBUG_MAPS", "AFL_QEMU_DISABLE_CACHE",
"AFL_QEMU_PERSISTENT_ADDR", "AFL_QEMU_PERSISTENT_CNT",
"AFL_QEMU_PERSISTENT_GPR", "AFL_QEMU_PERSISTENT_HOOK",
"AFL_QEMU_PERSISTENT_RET", "AFL_QEMU_PERSISTENT_RETADDR_OFFSET",
"AFL_QUIET", "AFL_RANDOM_ALLOC_CANARY", "AFL_REAL_PATH",
"AFL_SHUFFLE_QUEUE", "AFL_SKIP_BIN_CHECK", "AFL_SKIP_CPUFREQ",
"AFL_SKIP_CRASHES", "AFL_TMIN_EXACT", "AFL_TMPDIR", "AFL_TOKEN_FILE",
"AFL_TRACE_PC", "AFL_USE_ASAN", "AFL_USE_MSAN", "AFL_USE_TRACE_PC",
"AFL_USE_UBSAN", "AFL_WINE_PATH", NULL};
void detect_file_args(char **argv, u8 *prog_in, u8 *use_stdin) {
u32 i = 0;
u8 cwd[PATH_MAX];
if (getcwd(cwd, (size_t)sizeof(cwd)) == NULL) { PFATAL("getcwd() failed"); }
/* we are working with libc-heap-allocated argvs. So do not mix them with
* other allocation APIs like ck_alloc. That would disturb the free() calls.
*/
while (argv[i]) {
u8 *aa_loc = strstr(argv[i], "@@");
if (aa_loc) {
if (!prog_in) FATAL("@@ syntax is not supported by this tool.");
*use_stdin = 0;
if (prog_in[0] != 0) { // not afl-showmap special case
u8 *n_arg;
/* Be sure that we're always using fully-qualified paths. */
*aa_loc = 0;
/* Construct a replacement argv value. */
if (prog_in[0] == '/') {
n_arg = alloc_printf("%s%s%s", argv[i], prog_in, aa_loc + 2);
} else {
n_arg = alloc_printf("%s%s/%s%s", argv[i], cwd, prog_in, aa_loc + 2);
}
ck_free(argv[i]);
argv[i] = n_arg;
}
}
i++;
}
/* argvs are automatically freed at exit. */
}
/* duplicate the system argv so that
we can edit (and free!) it later */
char **argv_cpy_dup(int argc, char **argv) {
u32 i = 0;
char **ret = ck_alloc((argc + 1) * sizeof(char *));
for (i = 0; i < argc; i++) {
ret[i] = ck_strdup(argv[i]);
}
ret[i] = NULL;
return ret;
}
/* frees all args in the given argv,
previously created by argv_cpy_dup */
void argv_cpy_free(char **argv) {
u32 i = 0;
while (argv[i]) {
ck_free(argv[i]);
i++;
}
ck_free(argv);
}
/* Rewrite argv for QEMU. */
char **get_qemu_argv(u8 *own_loc, u8 **target_path_p, int argc, char **argv) {
char **new_argv = ck_alloc(sizeof(char *) * (argc + 4));
u8 * tmp, *cp = NULL, *rsl, *own_copy;
memcpy(new_argv + 3, argv + 1, (int)(sizeof(char *)) * argc);
new_argv[2] = *target_path_p;
new_argv[1] = "--";
/* Now we need to actually find the QEMU binary to put in argv[0]. */
tmp = getenv("AFL_PATH");
if (tmp) {
cp = alloc_printf("%s/afl-qemu-trace", tmp);
if (access(cp, X_OK)) FATAL("Unable to find '%s'", tmp);
*target_path_p = new_argv[0] = cp;
return new_argv;
}
own_copy = ck_strdup(own_loc);
rsl = strrchr(own_copy, '/');
if (rsl) {
*rsl = 0;
cp = alloc_printf("%s/afl-qemu-trace", own_copy);
ck_free(own_copy);
if (!access(cp, X_OK)) {
*target_path_p = new_argv[0] = cp;
return new_argv;
}
} else
ck_free(own_copy);
if (!access(BIN_PATH "/afl-qemu-trace", X_OK)) {
if (cp) ck_free(cp);
*target_path_p = new_argv[0] = ck_strdup(BIN_PATH "/afl-qemu-trace");
return new_argv;
}
SAYF("\n" cLRD "[-] " cRST
"Oops, unable to find the 'afl-qemu-trace' binary. The binary must be "
"built\n"
" separately by following the instructions in "
"afl->qemu_mode/README.md. "
"If you\n"
" already have the binary installed, you may need to specify "
"AFL_PATH in the\n"
" environment.\n\n"
" Of course, even without QEMU, afl-fuzz can still work with "
"binaries that are\n"
" instrumented at compile time with afl-gcc. It is also possible to "
"use it as a\n"
" traditional \"dumb\" fuzzer by specifying '-n' in the command "
"line.\n");
FATAL("Failed to locate 'afl-qemu-trace'.");
}
/* Rewrite argv for Wine+QEMU. */
char **get_wine_argv(u8 *own_loc, u8 **target_path_p, int argc, char **argv) {
char **new_argv = ck_alloc(sizeof(char *) * (argc + 3));
u8 * tmp, *cp = NULL, *rsl, *own_copy;
memcpy(new_argv + 2, argv + 1, (int)(sizeof(char *)) * argc);
new_argv[1] = *target_path_p;
/* Now we need to actually find the QEMU binary to put in argv[0]. */
tmp = getenv("AFL_PATH");
if (tmp) {
cp = alloc_printf("%s/afl-qemu-trace", tmp);
if (access(cp, X_OK)) FATAL("Unable to find '%s'", tmp);
ck_free(cp);
cp = alloc_printf("%s/afl-wine-trace", tmp);
if (access(cp, X_OK)) FATAL("Unable to find '%s'", tmp);
*target_path_p = new_argv[0] = cp;
return new_argv;
}
own_copy = ck_strdup(own_loc);
rsl = strrchr(own_copy, '/');
if (rsl) {
*rsl = 0;
cp = alloc_printf("%s/afl-qemu-trace", own_copy);
ck_free(own_copy);
if (!access(cp, X_OK)) {
if (cp != NULL) ck_free(cp);
cp = alloc_printf("%s/afl-wine-trace", own_copy);
if (!access(cp, X_OK)) {
*target_path_p = new_argv[0] = cp;
return new_argv;
}
}
} else
ck_free(own_copy);
u8 *ncp = BIN_PATH "/afl-qemu-trace";
if (!access(ncp, X_OK)) {
ncp = BIN_PATH "/afl-wine-trace";
if (!access(ncp, X_OK)) {
*target_path_p = new_argv[0] = ck_strdup(ncp);
return new_argv;
}
}
SAYF("\n" cLRD "[-] " cRST
"Oops, unable to find the '%s' binary. The binary must be "
"built\n"
" separately by following the instructions in "
"afl->qemu_mode/README.md. "
"If you\n"
" already have the binary installed, you may need to specify "
"AFL_PATH in the\n"
" environment.\n\n"
" Of course, even without QEMU, afl-fuzz can still work with "
"binaries that are\n"
" instrumented at compile time with afl-gcc. It is also possible to "
"use it as a\n"
" traditional \"dumb\" fuzzer by specifying '-n' in the command "
"line.\n",
ncp);
FATAL("Failed to locate '%s'.", ncp);
}
void check_environment_vars(char **envp) {
if (be_quiet) return;
int index = 0, found = 0;
char *env;
while ((env = envp[index++]) != NULL) {
if (strncmp(env, "ALF_", 4) == 0) {
WARNF("Potentially mistyped AFL environment variable: %s", env);
found++;
} else if (strncmp(env, "AFL_", 4) == 0) {
int i = 0, match = 0;
while (match == 0 && afl_environment_variables[i] != NULL)
if (strncmp(env, afl_environment_variables[i],
strlen(afl_environment_variables[i])) == 0 &&
env[strlen(afl_environment_variables[i])] == '=')
match = 1;
else
i++;
if (match == 0) {
WARNF("Mistyped AFL environment variable: %s", env);
found++;
}
}
}
if (found) sleep(2);
}
char *get_afl_env(char *env) {
char *val;
if ((val = getenv(env)) != NULL)
if (!be_quiet)
OKF("Loaded environment variable %s with value %s", env, val);
return val;
}