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- /*
- american fuzzy lop - map display utility
- ----------------------------------------
- Written and maintained by Michal Zalewski <lcamtuf@google.com>
- Copyright 2013, 2014, 2015, 2016, 2017 Google Inc. 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
- A very simple tool that runs the targeted binary and displays
- the contents of the trace bitmap in a human-readable form. Useful in
- scripts to eliminate redundant inputs and perform other checks.
- Exit code is 2 if the target program crashes; 1 if it times out or
- there is a problem executing it; or 0 if execution is successful.
- */
- #define AFL_MAIN
- #include "config.h"
- #include "types.h"
- #include "debug.h"
- #include "alloc-inl.h"
- #include "hash.h"
- #include <stdio.h>
- #include <unistd.h>
- #include <stdlib.h>
- #include <string.h>
- #include <time.h>
- #include <errno.h>
- #include <signal.h>
- #include <dirent.h>
- #include <fcntl.h>
- #include <sys/wait.h>
- #include <sys/time.h>
- #include <sys/shm.h>
- #include <sys/stat.h>
- #include <sys/types.h>
- #include <sys/resource.h>
- static s32 child_pid; /* PID of the tested program */
- static u8* trace_bits; /* SHM with instrumentation bitmap */
- static u8 *out_file, /* Trace output file */
- *doc_path, /* Path to docs */
- *target_path, /* Path to target binary */
- *at_file; /* Substitution string for @@ */
- static u32 exec_tmout; /* Exec timeout (ms) */
- static u64 mem_limit = MEM_LIMIT; /* Memory limit (MB) */
- static s32 shm_id; /* ID of the SHM region */
- static u8 quiet_mode, /* Hide non-essential messages? */
- edges_only, /* Ignore hit counts? */
- cmin_mode, /* Generate output in afl-cmin mode? */
- binary_mode, /* Write output as a binary map */
- keep_cores; /* Allow coredumps? */
- static volatile u8
- stop_soon, /* Ctrl-C pressed? */
- child_timed_out, /* Child timed out? */
- child_crashed; /* Child crashed? */
- /* Classify tuple counts. Instead of mapping to individual bits, as in
- afl-fuzz.c, we map to more user-friendly numbers between 1 and 8. */
- static const u8 count_class_human[256] = {
- [0] = 0,
- [1] = 1,
- [2] = 2,
- [3] = 3,
- [4 ... 7] = 4,
- [8 ... 15] = 5,
- [16 ... 31] = 6,
- [32 ... 127] = 7,
- [128 ... 255] = 8
- };
- static const u8 count_class_binary[256] = {
- [0] = 0,
- [1] = 1,
- [2] = 2,
- [3] = 4,
- [4 ... 7] = 8,
- [8 ... 15] = 16,
- [16 ... 31] = 32,
- [32 ... 127] = 64,
- [128 ... 255] = 128
- };
- static void classify_counts(u8* mem, const u8* map) {
- u32 i = MAP_SIZE;
- if (edges_only) {
- while (i--) {
- if (*mem) *mem = 1;
- mem++;
- }
- } else {
- while (i--) {
- *mem = map[*mem];
- mem++;
- }
- }
- }
- /* Get rid of shared memory (atexit handler). */
- static void remove_shm(void) {
- shmctl(shm_id, IPC_RMID, NULL);
- }
- /* Configure shared memory. */
- static void setup_shm(void) {
- u8* shm_str;
- shm_id = shmget(IPC_PRIVATE, MAP_SIZE, IPC_CREAT | IPC_EXCL | 0600);
- if (shm_id < 0) PFATAL("shmget() failed");
- atexit(remove_shm);
- shm_str = alloc_printf("%d", shm_id);
- setenv(SHM_ENV_VAR, shm_str, 1);
- ck_free(shm_str);
- trace_bits = shmat(shm_id, NULL, 0);
-
- if (!trace_bits) PFATAL("shmat() failed");
- }
- /* Write results. */
- static u32 write_results(void) {
- s32 fd;
- u32 i, ret = 0;
- u8 cco = !!getenv("AFL_CMIN_CRASHES_ONLY"),
- caa = !!getenv("AFL_CMIN_ALLOW_ANY");
- if (!strncmp(out_file, "/dev/", 5)) {
- fd = open(out_file, O_WRONLY, 0600);
- if (fd < 0) PFATAL("Unable to open '%s'", out_file);
- } else if (!strcmp(out_file, "-")) {
- fd = dup(1);
- if (fd < 0) PFATAL("Unable to open stdout");
- } else {
- unlink(out_file); /* Ignore errors */
- fd = open(out_file, O_WRONLY | O_CREAT | O_EXCL, 0600);
- if (fd < 0) PFATAL("Unable to create '%s'", out_file);
- }
- if (binary_mode) {
- for (i = 0; i < MAP_SIZE; i++)
- if (trace_bits[i]) ret++;
-
- ck_write(fd, trace_bits, MAP_SIZE, out_file);
- close(fd);
- } else {
- FILE* f = fdopen(fd, "w");
- if (!f) PFATAL("fdopen() failed");
- for (i = 0; i < MAP_SIZE; i++) {
- if (!trace_bits[i]) continue;
- ret++;
- if (cmin_mode) {
- if (child_timed_out) break;
- if (!caa && child_crashed != cco) break;
- fprintf(f, "%u%u\n", trace_bits[i], i);
- } else fprintf(f, "%06u:%u\n", i, trace_bits[i]);
- }
-
- fclose(f);
- }
- return ret;
- }
- /* Handle timeout signal. */
- static void handle_timeout(int sig) {
- child_timed_out = 1;
- if (child_pid > 0) kill(child_pid, SIGKILL);
- }
- /* Execute target application. */
- static void run_target(char** argv) {
- static struct itimerval it;
- int status = 0;
- if (!quiet_mode)
- SAYF("-- Program output begins --\n" cRST);
- MEM_BARRIER();
- child_pid = fork();
- if (child_pid < 0) PFATAL("fork() failed");
- if (!child_pid) {
- struct rlimit r;
- if (quiet_mode) {
- s32 fd = open("/dev/null", O_RDWR);
- if (fd < 0 || dup2(fd, 1) < 0 || dup2(fd, 2) < 0) {
- *(u32*)trace_bits = EXEC_FAIL_SIG;
- PFATAL("Descriptor initialization failed");
- }
- close(fd);
- }
- if (mem_limit) {
- r.rlim_max = r.rlim_cur = ((rlim_t)mem_limit) << 20;
- #ifdef RLIMIT_AS
- setrlimit(RLIMIT_AS, &r); /* Ignore errors */
- #else
- setrlimit(RLIMIT_DATA, &r); /* Ignore errors */
- #endif /* ^RLIMIT_AS */
- }
- if (!keep_cores) r.rlim_max = r.rlim_cur = 0;
- else r.rlim_max = r.rlim_cur = RLIM_INFINITY;
- setrlimit(RLIMIT_CORE, &r); /* Ignore errors */
- if (!getenv("LD_BIND_LAZY")) setenv("LD_BIND_NOW", "1", 0);
- setsid();
- execv(target_path, argv);
- *(u32*)trace_bits = EXEC_FAIL_SIG;
- exit(0);
- }
- /* Configure timeout, wait for child, cancel timeout. */
- if (exec_tmout) {
- child_timed_out = 0;
- it.it_value.tv_sec = (exec_tmout / 1000);
- it.it_value.tv_usec = (exec_tmout % 1000) * 1000;
- }
- setitimer(ITIMER_REAL, &it, NULL);
- if (waitpid(child_pid, &status, 0) <= 0) FATAL("waitpid() failed");
- child_pid = 0;
- it.it_value.tv_sec = 0;
- it.it_value.tv_usec = 0;
- setitimer(ITIMER_REAL, &it, NULL);
- MEM_BARRIER();
- /* Clean up bitmap, analyze exit condition, etc. */
- if (*(u32*)trace_bits == EXEC_FAIL_SIG)
- FATAL("Unable to execute '%s'", argv[0]);
- classify_counts(trace_bits, binary_mode ?
- count_class_binary : count_class_human);
- if (!quiet_mode)
- SAYF(cRST "-- Program output ends --\n");
- if (!child_timed_out && !stop_soon && WIFSIGNALED(status))
- child_crashed = 1;
- if (!quiet_mode) {
- if (child_timed_out)
- SAYF(cLRD "\n+++ Program timed off +++\n" cRST);
- else if (stop_soon)
- SAYF(cLRD "\n+++ Program aborted by user +++\n" cRST);
- else if (child_crashed)
- SAYF(cLRD "\n+++ Program killed by signal %u +++\n" cRST, WTERMSIG(status));
- }
- }
- /* Handle Ctrl-C and the like. */
- static void handle_stop_sig(int sig) {
- stop_soon = 1;
- if (child_pid > 0) kill(child_pid, SIGKILL);
- }
- /* Do basic preparations - persistent fds, filenames, etc. */
- static void set_up_environment(void) {
- setenv("ASAN_OPTIONS", "abort_on_error=1:"
- "detect_leaks=0:"
- "symbolize=0:"
- "allocator_may_return_null=1", 0);
- setenv("MSAN_OPTIONS", "exit_code=" STRINGIFY(MSAN_ERROR) ":"
- "symbolize=0:"
- "abort_on_error=1:"
- "allocator_may_return_null=1:"
- "msan_track_origins=0", 0);
- if (getenv("AFL_PRELOAD")) {
- setenv("LD_PRELOAD", getenv("AFL_PRELOAD"), 1);
- setenv("DYLD_INSERT_LIBRARIES", getenv("AFL_PRELOAD"), 1);
- }
- }
- /* Setup signal handlers, duh. */
- static void setup_signal_handlers(void) {
- struct sigaction sa;
- sa.sa_handler = NULL;
- sa.sa_flags = SA_RESTART;
- sa.sa_sigaction = NULL;
- sigemptyset(&sa.sa_mask);
- /* Various ways of saying "stop". */
- sa.sa_handler = handle_stop_sig;
- sigaction(SIGHUP, &sa, NULL);
- sigaction(SIGINT, &sa, NULL);
- sigaction(SIGTERM, &sa, NULL);
- /* Exec timeout notifications. */
- sa.sa_handler = handle_timeout;
- sigaction(SIGALRM, &sa, NULL);
- }
- /* Detect @@ in args. */
- static void detect_file_args(char** argv) {
- u32 i = 0;
- u8* cwd = getcwd(NULL, 0);
- if (!cwd) PFATAL("getcwd() failed");
- while (argv[i]) {
- u8* aa_loc = strstr(argv[i], "@@");
- if (aa_loc) {
- u8 *aa_subst, *n_arg;
- if (!at_file) FATAL("@@ syntax is not supported by this tool.");
- /* Be sure that we're always using fully-qualified paths. */
- if (at_file[0] == '/') aa_subst = at_file;
- else aa_subst = alloc_printf("%s/%s", cwd, at_file);
- /* Construct a replacement argv value. */
- *aa_loc = 0;
- n_arg = alloc_printf("%s%s%s", argv[i], aa_subst, aa_loc + 2);
- argv[i] = n_arg;
- *aa_loc = '@';
- if (at_file[0] != '/') ck_free(aa_subst);
- }
- i++;
- }
- free(cwd); /* not tracked */
- }
- /* Show banner. */
- static void show_banner(void) {
- SAYF(cCYA "afl-showmap " cBRI VERSION cRST " by <lcamtuf@google.com>\n");
- }
- /* Display usage hints. */
- static void usage(u8* argv0) {
- show_banner();
- SAYF("\n%s [ options ] -- /path/to/target_app [ ... ]\n\n"
- "Required parameters:\n\n"
- " -o file - file to write the trace data to\n\n"
- "Execution control settings:\n\n"
- " -t msec - timeout for each run (none)\n"
- " -m megs - memory limit for child process (%u MB)\n"
- " -Q - use binary-only instrumentation (QEMU mode)\n\n"
- "Other settings:\n\n"
- " -q - sink program's output and don't show messages\n"
- " -e - show edge coverage only, ignore hit counts\n"
- " -c - allow core dumps\n\n"
- "This tool displays raw tuple data captured by AFL instrumentation.\n"
- "For additional help, consult %s/README.\n\n" cRST,
- argv0, MEM_LIMIT, doc_path);
- exit(1);
- }
- /* Find binary. */
- static void find_binary(u8* fname) {
- u8* env_path = 0;
- struct stat st;
- if (strchr(fname, '/') || !(env_path = getenv("PATH"))) {
- target_path = ck_strdup(fname);
- if (stat(target_path, &st) || !S_ISREG(st.st_mode) ||
- !(st.st_mode & 0111) || st.st_size < 4)
- FATAL("Program '%s' not found or not executable", fname);
- } else {
- while (env_path) {
- u8 *cur_elem, *delim = strchr(env_path, ':');
- if (delim) {
- cur_elem = ck_alloc(delim - env_path + 1);
- memcpy(cur_elem, env_path, delim - env_path);
- delim++;
- } else cur_elem = ck_strdup(env_path);
- env_path = delim;
- if (cur_elem[0])
- target_path = alloc_printf("%s/%s", cur_elem, fname);
- else
- target_path = ck_strdup(fname);
- ck_free(cur_elem);
- if (!stat(target_path, &st) && S_ISREG(st.st_mode) &&
- (st.st_mode & 0111) && st.st_size >= 4) break;
- ck_free(target_path);
- target_path = 0;
- }
- if (!target_path) FATAL("Program '%s' not found or not executable", fname);
- }
- }
- /* Fix up argv for QEMU. */
- static char** get_qemu_argv(u8* own_loc, char** argv, int argc) {
- char** new_argv = ck_alloc(sizeof(char*) * (argc + 4));
- u8 *tmp, *cp, *rsl, *own_copy;
- /* Workaround for a QEMU stability glitch. */
- setenv("QEMU_LOG", "nochain", 1);
- memcpy(new_argv + 3, argv + 1, sizeof(char*) * argc);
- new_argv[2] = target_path;
- new_argv[1] = "--";
- /* Now we need to actually find qemu for 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 = 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 = new_argv[0] = cp;
- return new_argv;
- }
- } else ck_free(own_copy);
- if (!access(BIN_PATH "/afl-qemu-trace", X_OK)) {
- target_path = new_argv[0] = BIN_PATH "/afl-qemu-trace";
- return new_argv;
- }
- FATAL("Unable to find 'afl-qemu-trace'.");
- }
- /* Main entry point */
- int main(int argc, char** argv) {
- s32 opt;
- u8 mem_limit_given = 0, timeout_given = 0, qemu_mode = 0;
- u32 tcnt;
- char** use_argv;
- doc_path = access(DOC_PATH, F_OK) ? "docs" : DOC_PATH;
- while ((opt = getopt(argc,argv,"+o:m:t:A:eqZQbc")) > 0)
- switch (opt) {
- case 'o':
- if (out_file) FATAL("Multiple -o options not supported");
- out_file = optarg;
- break;
- case 'm': {
- u8 suffix = 'M';
- if (mem_limit_given) FATAL("Multiple -m options not supported");
- mem_limit_given = 1;
- if (!strcmp(optarg, "none")) {
- mem_limit = 0;
- break;
- }
- if (sscanf(optarg, "%llu%c", &mem_limit, &suffix) < 1 ||
- optarg[0] == '-') FATAL("Bad syntax used for -m");
- switch (suffix) {
- case 'T': mem_limit *= 1024 * 1024; break;
- case 'G': mem_limit *= 1024; break;
- case 'k': mem_limit /= 1024; break;
- case 'M': break;
- default: FATAL("Unsupported suffix or bad syntax for -m");
- }
- if (mem_limit < 5) FATAL("Dangerously low value of -m");
- if (sizeof(rlim_t) == 4 && mem_limit > 2000)
- FATAL("Value of -m out of range on 32-bit systems");
- }
- break;
- case 't':
- if (timeout_given) FATAL("Multiple -t options not supported");
- timeout_given = 1;
- if (strcmp(optarg, "none")) {
- exec_tmout = atoi(optarg);
- if (exec_tmout < 20 || optarg[0] == '-')
- FATAL("Dangerously low value of -t");
- }
- break;
- case 'e':
- if (edges_only) FATAL("Multiple -e options not supported");
- edges_only = 1;
- break;
- case 'q':
- if (quiet_mode) FATAL("Multiple -q options not supported");
- quiet_mode = 1;
- break;
- case 'Z':
- /* This is an undocumented option to write data in the syntax expected
- by afl-cmin. Nobody else should have any use for this. */
- cmin_mode = 1;
- quiet_mode = 1;
- break;
- case 'A':
- /* Another afl-cmin specific feature. */
- at_file = optarg;
- break;
- case 'Q':
- if (qemu_mode) FATAL("Multiple -Q options not supported");
- if (!mem_limit_given) mem_limit = MEM_LIMIT_QEMU;
- qemu_mode = 1;
- break;
- case 'b':
- /* Secret undocumented mode. Writes output in raw binary format
- similar to that dumped by afl-fuzz in <out_dir/queue/fuzz_bitmap. */
- binary_mode = 1;
- break;
- case 'c':
- if (keep_cores) FATAL("Multiple -c options not supported");
- keep_cores = 1;
- break;
- default:
- usage(argv[0]);
- }
- if (optind == argc || !out_file) usage(argv[0]);
- setup_shm();
- setup_signal_handlers();
- set_up_environment();
- find_binary(argv[optind]);
- if (!quiet_mode) {
- show_banner();
- ACTF("Executing '%s'...\n", target_path);
- }
- detect_file_args(argv + optind);
- if (qemu_mode)
- use_argv = get_qemu_argv(argv[0], argv + optind, argc - optind);
- else
- use_argv = argv + optind;
- run_target(use_argv);
- tcnt = write_results();
- if (!quiet_mode) {
- if (!tcnt) FATAL("No instrumentation detected" cRST);
- OKF("Captured %u tuples in '%s'." cRST, tcnt, out_file);
- }
- exit(child_crashed * 2 + child_timed_out);
- }
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