/* american fuzzy lop++ - map display utility ------------------------------------------ Originally written by Michal Zalewski Forkserver design by Jann Horn Now maintained by Marc Heuse , Heiko Eißfeldt and Andrea Fioraldi 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 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 #ifdef __ANDROID__ #include "android-ashmem.h" #endif #include "config.h" #include "types.h" #include "debug.h" #include "alloc-inl.h" #include "hash.h" #include "sharedmem.h" #include "forkserver.h" #include "common.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include u8* trace_bits; /* SHM with instrumentation bitmap */ s32 forksrv_pid, /* PID of the fork server */ child_pid; /* PID of the tested program */ s32 fsrv_ctl_fd, /* Fork server control pipe (write) */ fsrv_st_fd; /* Fork server status pipe (read) */ s32 out_fd; /* Persistent fd for stdin_file */ s32 dev_null_fd = -1; /* FD to /dev/null */ s32 out_fd = -1, out_dir_fd = -1, dev_urandom_fd = -1; FILE* plot_file; u8 uses_asan, be_quiet; u8* trace_bits; /* SHM with instrumentation bitmap */ u8 *out_file, /* Trace output file */ *stdin_file, /* stdin file */ *in_dir, /* input folder */ *doc_path, /* Path to docs */ *at_file = NULL; /* Substitution string for @@ */ static u8* in_data; /* Input data */ u32 exec_tmout; /* Exec timeout (ms) */ static u32 total, highest; /* tuple content information */ static u32 in_len, /* Input data length */ arg_offset, total_execs; /* Total number of execs */ u64 mem_limit = MEM_LIMIT; /* Memory limit (MB) */ u8 quiet_mode, /* Hide non-essential messages? */ edges_only, /* Ignore hit counts? */ raw_instr_output, /* Do not apply AFL filters */ cmin_mode, /* Generate output in afl-cmin mode? */ binary_mode, /* Write output as a binary map */ use_stdin = 1, /* use stdin - unused here */ keep_cores; /* Allow coredumps? */ static volatile u8 stop_soon, /* Ctrl-C pressed? */ child_timed_out, /* Child timed out? */ child_crashed; /* Child crashed? */ static u8 qemu_mode; /* 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 if (!raw_instr_output) { while (i--) { *mem = map[*mem]; mem++; } } } /* Get rid of temp files (atexit handler). */ static void at_exit_handler(void) { if (stdin_file) unlink(stdin_file); } /* Write results. */ static u32 write_results_to_file(u8* out_file) { 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++; total += trace_bits[i]; if (highest < trace_bits[i]) highest = trace_bits[i]; 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; } /* Write results. */ static u32 write_results(void) { return write_results_to_file(out_file); } /* Write output file. */ static s32 write_to_file(u8* path, u8* mem, u32 len) { s32 ret; unlink(path); /* Ignore errors */ ret = open(path, O_RDWR | O_CREAT | O_EXCL, 0600); if (ret < 0) PFATAL("Unable to create '%s'", path); ck_write(ret, mem, len, path); lseek(ret, 0, SEEK_SET); return ret; } /* Write modified data to file for testing. If use_stdin is clear, the old file is unlinked and a new one is created. Otherwise, out_fd is rewound and truncated. */ static void write_to_testcase(void* mem, u32 len) { lseek(out_fd, 0, SEEK_SET); ck_write(out_fd, mem, len, out_file); if (ftruncate(out_fd, len)) PFATAL("ftruncate() failed"); lseek(out_fd, 0, SEEK_SET); } /* Execute target application. Returns 0 if the changes are a dud, or 1 if they should be kept. */ static u8 run_target_forkserver(char** argv, u8* mem, u32 len) { static struct itimerval it; static u32 prev_timed_out = 0; int status = 0; memset(trace_bits, 0, MAP_SIZE); MEM_BARRIER(); write_to_testcase(mem, len); s32 res; /* we have the fork server up and running, so simply tell it to have at it, and then read back PID. */ if ((res = write(fsrv_ctl_fd, &prev_timed_out, 4)) != 4) { if (stop_soon) return 0; RPFATAL(res, "Unable to request new process from fork server (OOM?)"); } if ((res = read(fsrv_st_fd, &child_pid, 4)) != 4) { if (stop_soon) return 0; RPFATAL(res, "Unable to request new process from fork server (OOM?)"); } if (child_pid <= 0) FATAL("Fork server is misbehaving (OOM?)"); /* Configure timeout, wait for child, cancel timeout. */ if (exec_tmout) { it.it_value.tv_sec = (exec_tmout / 1000); it.it_value.tv_usec = (exec_tmout % 1000) * 1000; } setitimer(ITIMER_REAL, &it, NULL); if ((res = read(fsrv_st_fd, &status, 4)) != 4) { if (stop_soon) return 0; RPFATAL(res, "Unable to communicate with fork server (OOM?)"); } 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); total_execs++; if (stop_soon) { SAYF(cRST cLRD "\n+++ afl-showmap folder mode aborted by user +++\n" cRST); close(write_to_file(out_file, in_data, in_len)); exit(1); } /* Always discard inputs that time out. */ if (child_timed_out) { return 0; } /* Handle crashing inputs depending on current mode. */ if (WIFSIGNALED(status) || (WIFEXITED(status) && WEXITSTATUS(status) == MSAN_ERROR) || (WIFEXITED(status) && WEXITSTATUS(status))) { return 0; } return 0; } /* Read initial file. */ u32 read_file(u8* in_file) { struct stat st; s32 fd = open(in_file, O_RDONLY); if (fd < 0) WARNF("Unable to open '%s'", in_file); if (fstat(fd, &st) || !st.st_size) WARNF("Zero-sized input file '%s'.", in_file); in_len = st.st_size; in_data = ck_alloc_nozero(in_len); ck_read(fd, in_data, in_len, in_file); close(fd); // OKF("Read %u byte%s from '%s'.", in_len, in_len == 1 ? "" : "s", in_file); return in_len; } /* 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 (get_afl_env("AFL_PRELOAD")) { if (qemu_mode) { u8* qemu_preload = getenv("QEMU_SET_ENV"); u8* afl_preload = getenv("AFL_PRELOAD"); u8* buf; s32 i, afl_preload_size = strlen(afl_preload); for (i = 0; i < afl_preload_size; ++i) { if (afl_preload[i] == ',') PFATAL( "Comma (',') is not allowed in AFL_PRELOAD when -Q is " "specified!"); } if (qemu_preload) buf = alloc_printf("%s,LD_PRELOAD=%s,DYLD_INSERT_LIBRARIES=%s", qemu_preload, afl_preload, afl_preload); else buf = alloc_printf("LD_PRELOAD=%s,DYLD_INSERT_LIBRARIES=%s", afl_preload, afl_preload); setenv("QEMU_SET_ENV", buf, 1); ck_free(buf); } else { 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); } /* Show banner. */ static void show_banner(void) { SAYF(cCYA "afl-showmap" VERSION cRST " by Michal Zalewski\n"); } /* Display usage hints. */ static void usage(u8* argv0) { show_banner(); SAYF( "\n%s [ options ] -- /path/to/target_app [ ... ]\n\n" "Required parameters:\n" " -o file - file to write the trace data to\n\n" "Execution control settings:\n" " -t msec - timeout for each run (none)\n" " -m megs - memory limit for child process (%d MB)\n" " -Q - use binary-only instrumentation (QEMU mode)\n" " -U - use Unicorn-based instrumentation (Unicorn mode)\n" " -W - use qemu-based instrumentation with Wine (Wine mode)\n" " (Not necessary, here for consistency with other afl-* " "tools)\n\n" "Other settings:\n" " -i dir - process all files in this directory, -o must be a " "directory\n" " and each bitmap will be written there individually.\n" " -q - sink program's output and don't show messages\n" " -e - show edge coverage only, ignore hit counts\n" " -r - show real tuple values instead of AFL filter values\n" " -c - allow core dumps\n\n" "This tool displays raw tuple data captured by AFL instrumentation.\n" "For additional help, consult %s/README.md.\n\n" "Environment variables used:\n" "AFL_PRELOAD: LD_PRELOAD / DYLD_INSERT_LIBRARIES settings for target\n" "AFL_DEBUG: enable extra developer output\n" "AFL_QUIET: do not print extra informational output" "AFL_CMIN_CRASHES_ONLY: (cmin_mode) only write tuples for crashing " "inputs\n" "AFL_CMIN_ALLOW_ANY: (cmin_mode) write tuples for crashing inputs also\n" "LD_BIND_LAZY: do not set LD_BIND_NOW env var for target\n", 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); } } /* Main entry point */ int main(int argc, char** argv, char** envp) { s32 opt, i; u8 mem_limit_given = 0, timeout_given = 0, unicorn_mode = 0, use_wine = 0; u32 tcnt = 0; char** use_argv; doc_path = access(DOC_PATH, F_OK) ? "docs" : DOC_PATH; if (getenv("AFL_QUIET") != NULL) be_quiet = 1; while ((opt = getopt(argc, argv, "+i:o:f:m:t:A:eqZQUWbcrh")) > 0) switch (opt) { case 'i': if (in_dir) FATAL("Multiple -i options not supported"); in_dir = optarg; break; 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 'f': // only in here to avoid a compiler warning for use_stdin use_stdin = 0; FATAL("Option -f is not supported in afl-showmap"); 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"); if (raw_instr_output) FATAL("-e and -r are mutually exclusive"); 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 'U': if (unicorn_mode) FATAL("Multiple -U options not supported"); if (!mem_limit_given) mem_limit = MEM_LIMIT_UNICORN; unicorn_mode = 1; break; case 'W': /* Wine+QEMU mode */ if (use_wine) FATAL("Multiple -W options not supported"); qemu_mode = 1; use_wine = 1; if (!mem_limit_given) mem_limit = 0; break; case 'b': /* Secret undocumented mode. Writes output in raw binary format similar to that dumped by afl-fuzz in d_name[0] == '.') continue; // skip anything that starts with '.' #if defined(DT_REG) /* Posix and Solaris do not know d_type and DT_REG */ if (dir_ent->d_type != DT_REG) continue; // only regular files #endif snprintf(infile, sizeof(infile), "%s/%s", in_dir, dir_ent->d_name); #if !defined(DT_REG) /* use stat() */ if (-1 == stat(infile, &statbuf) || !S_ISREG(statbuf.st_mode)) continue; #endif snprintf(outfile, sizeof(outfile), "%s/%s", out_file, dir_ent->d_name); if (read_file(infile)) { run_target_forkserver(use_argv, in_data, in_len); ck_free(in_data); tcnt = write_results_to_file(outfile); } } if (!quiet_mode) OKF("Processed %u input files.", total_execs); } else { run_target(use_argv); tcnt = write_results(); } if (!quiet_mode) { if (!tcnt) FATAL("No instrumentation detected" cRST); OKF("Captured %u tuples (highest value %u, total values %u) in '%s'." cRST, tcnt, highest, total, out_file); } if (stdin_file) { unlink(stdin_file); stdin_file = NULL; } exit(child_crashed * 2 + child_timed_out); }