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authorAndrea Fioraldi <andreafioraldi@gmail.com>2019-08-27 13:31:35 +0200
committerAndrea Fioraldi <andreafioraldi@gmail.com>2019-08-27 13:31:35 +0200
commit0e59a591693901ec6a69c7de2e9de2dcca52c101 (patch)
tree6a0a3be742f26e7cf6cbfcc1779a85e29c6d9db1 /afl-as.c
parentd3d0682310b840b027083133837bcd9be0638281 (diff)
downloadafl++-0e59a591693901ec6a69c7de2e9de2dcca52c101.tar.gz
include and src folders
Diffstat (limited to 'afl-as.c')
-rw-r--r--afl-as.c550
1 files changed, 0 insertions, 550 deletions
diff --git a/afl-as.c b/afl-as.c
deleted file mode 100644
index 94595f24..00000000
--- a/afl-as.c
+++ /dev/null
@@ -1,550 +0,0 @@
-/*
-   american fuzzy lop - wrapper for GNU as
-   ---------------------------------------
-
-   Written and maintained by Michal Zalewski <lcamtuf@google.com>
-
-   Copyright 2013, 2014, 2015 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
-
-   The sole purpose of this wrapper is to preprocess assembly files generated
-   by GCC / clang and inject the instrumentation bits included from afl-as.h. It
-   is automatically invoked by the toolchain when compiling programs using
-   afl-gcc / afl-clang.
-
-   Note that it's an explicit non-goal to instrument hand-written assembly,
-   be it in separate .s files or in __asm__ blocks. The only aspiration this
-   utility has right now is to be able to skip them gracefully and allow the
-   compilation process to continue.
-
-   That said, see experimental/clang_asm_normalize/ for a solution that may
-   allow clang users to make things work even with hand-crafted assembly. Just
-   note that there is no equivalent for GCC.
-
- */
-
-#define AFL_MAIN
-
-#include "config.h"
-#include "types.h"
-#include "debug.h"
-#include "alloc-inl.h"
-
-#include "afl-as.h"
-
-#include <stdio.h>
-#include <unistd.h>
-#include <stdlib.h>
-#include <string.h>
-#include <time.h>
-#include <ctype.h>
-#include <fcntl.h>
-
-#include <sys/wait.h>
-#include <sys/time.h>
-
-static u8** as_params;          /* Parameters passed to the real 'as'   */
-
-static u8*  input_file;         /* Originally specified input file      */
-static u8*  modified_file;      /* Instrumented file for the real 'as'  */
-
-static u8   be_quiet,           /* Quiet mode (no stderr output)        */
-            clang_mode,         /* Running in clang mode?               */
-            pass_thru,          /* Just pass data through?              */
-            just_version,       /* Just show version?                   */
-            sanitizer;          /* Using ASAN / MSAN                    */
-
-static u32  inst_ratio = 100,   /* Instrumentation probability (%)      */
-            as_par_cnt = 1;     /* Number of params to 'as'             */
-
-/* If we don't find --32 or --64 in the command line, default to 
-   instrumentation for whichever mode we were compiled with. This is not
-   perfect, but should do the trick for almost all use cases. */
-
-#ifdef __x86_64__
-
-static u8   use_64bit = 1;
-
-#else
-
-static u8   use_64bit = 0;
-
-#ifdef __APPLE__
-#  error "Sorry, 32-bit Apple platforms are not supported."
-#endif /* __APPLE__ */
-
-#endif /* ^__x86_64__ */
-
-
-/* Examine and modify parameters to pass to 'as'. Note that the file name
-   is always the last parameter passed by GCC, so we exploit this property
-   to keep the code simple. */
-
-static void edit_params(int argc, char** argv) {
-
-  u8 *tmp_dir = getenv("TMPDIR"), *afl_as = getenv("AFL_AS");
-  u32 i;
-
-#ifdef __APPLE__
-
-  u8 use_clang_as = 0;
-
-  /* On MacOS X, the Xcode cctool 'as' driver is a bit stale and does not work
-     with the code generated by newer versions of clang that are hand-built
-     by the user. See the thread here: http://goo.gl/HBWDtn.
-
-     To work around this, when using clang and running without AFL_AS
-     specified, we will actually call 'clang -c' instead of 'as -q' to
-     compile the assembly file.
-
-     The tools aren't cmdline-compatible, but at least for now, we can
-     seemingly get away with this by making only very minor tweaks. Thanks
-     to Nico Weber for the idea. */
-
-  if (clang_mode && !afl_as) {
-
-    use_clang_as = 1;
-
-    afl_as = getenv("AFL_CC");
-    if (!afl_as) afl_as = getenv("AFL_CXX");
-    if (!afl_as) afl_as = "clang";
-
-  }
-
-#endif /* __APPLE__ */
-
-  /* Although this is not documented, GCC also uses TEMP and TMP when TMPDIR
-     is not set. We need to check these non-standard variables to properly
-     handle the pass_thru logic later on. */
-
-  if (!tmp_dir) tmp_dir = getenv("TEMP");
-  if (!tmp_dir) tmp_dir = getenv("TMP");
-  if (!tmp_dir) tmp_dir = "/tmp";
-
-  as_params = ck_alloc((argc + 32) * sizeof(u8*));
-
-  as_params[0] = afl_as ? afl_as : (u8*)"as";
-
-  as_params[argc] = 0;
-
-  for (i = 1; i < argc - 1; i++) {
-
-    if (!strcmp(argv[i], "--64")) use_64bit = 1;
-    else if (!strcmp(argv[i], "--32")) use_64bit = 0;
-
-#ifdef __APPLE__
-
-    /* The Apple case is a bit different... */
-
-    if (!strcmp(argv[i], "-arch") && i + 1 < argc) {
-
-      if (!strcmp(argv[i + 1], "x86_64")) use_64bit = 1;
-      else if (!strcmp(argv[i + 1], "i386"))
-        FATAL("Sorry, 32-bit Apple platforms are not supported.");
-
-    }
-
-    /* Strip options that set the preference for a particular upstream
-       assembler in Xcode. */
-
-    if (clang_mode && (!strcmp(argv[i], "-q") || !strcmp(argv[i], "-Q")))
-      continue;
-
-#endif /* __APPLE__ */
-
-    as_params[as_par_cnt++] = argv[i];
-
-  }
-
-#ifdef __APPLE__
-
-  /* When calling clang as the upstream assembler, append -c -x assembler
-     and hope for the best. */
-
-  if (use_clang_as) {
-
-    as_params[as_par_cnt++] = "-c";
-    as_params[as_par_cnt++] = "-x";
-    as_params[as_par_cnt++] = "assembler";
-
-  }
-
-#endif /* __APPLE__ */
-
-  input_file = argv[argc - 1];
-
-  if (input_file[0] == '-') {
-
-    if (!strcmp(input_file + 1, "-version")) {
-      just_version = 1;
-      modified_file = input_file;
-      goto wrap_things_up;
-    }
-
-    if (input_file[1]) FATAL("Incorrect use (not called through afl-gcc?)");
-      else input_file = NULL;
-
-  } else {
-
-    /* Check if this looks like a standard invocation as a part of an attempt
-       to compile a program, rather than using gcc on an ad-hoc .s file in
-       a format we may not understand. This works around an issue compiling
-       NSS. */
-
-    if (strncmp(input_file, tmp_dir, strlen(tmp_dir)) &&
-        strncmp(input_file, "/var/tmp/", 9) &&
-        strncmp(input_file, "/tmp/", 5)) pass_thru = 1;
-
-  }
-
-  modified_file = alloc_printf("%s/.afl-%u-%u.s", tmp_dir, getpid(),
-                               (u32)time(NULL));
-
-wrap_things_up:
-
-  as_params[as_par_cnt++] = modified_file;
-  as_params[as_par_cnt]   = NULL;
-
-}
-
-
-/* Process input file, generate modified_file. Insert instrumentation in all
-   the appropriate places. */
-
-static void add_instrumentation(void) {
-
-  static u8 line[MAX_LINE];
-
-  FILE* inf;
-  FILE* outf;
-  s32 outfd;
-  u32 ins_lines = 0;
-
-  u8  instr_ok = 0, skip_csect = 0, skip_next_label = 0,
-      skip_intel = 0, skip_app = 0, instrument_next = 0;
-
-#ifdef __APPLE__
-
-  u8* colon_pos;
-
-#endif /* __APPLE__ */
-
-  if (input_file) {
-
-    inf = fopen(input_file, "r");
-    if (!inf) PFATAL("Unable to read '%s'", input_file);
-
-  } else inf = stdin;
-
-  outfd = open(modified_file, O_WRONLY | O_EXCL | O_CREAT, 0600);
-
-  if (outfd < 0) PFATAL("Unable to write to '%s'", modified_file);
-
-  outf = fdopen(outfd, "w");
-
-  if (!outf) PFATAL("fdopen() failed");  
-
-  while (fgets(line, MAX_LINE, inf)) {
-
-    /* In some cases, we want to defer writing the instrumentation trampoline
-       until after all the labels, macros, comments, etc. If we're in this
-       mode, and if the line starts with a tab followed by a character, dump
-       the trampoline now. */
-
-    if (!pass_thru && !skip_intel && !skip_app && !skip_csect && instr_ok &&
-        instrument_next && line[0] == '\t' && isalpha(line[1])) {
-
-      fprintf(outf, use_64bit ? trampoline_fmt_64 : trampoline_fmt_32,
-              R(MAP_SIZE));
-
-      instrument_next = 0;
-      ins_lines++;
-
-    }
-
-    /* Output the actual line, call it a day in pass-thru mode. */
-
-    fputs(line, outf);
-
-    if (pass_thru) continue;
-
-    /* All right, this is where the actual fun begins. For one, we only want to
-       instrument the .text section. So, let's keep track of that in processed
-       files - and let's set instr_ok accordingly. */
-
-    if (line[0] == '\t' && line[1] == '.') {
-
-      /* OpenBSD puts jump tables directly inline with the code, which is
-         a bit annoying. They use a specific format of p2align directives
-         around them, so we use that as a signal. */
-
-      if (!clang_mode && instr_ok && !strncmp(line + 2, "p2align ", 8) &&
-          isdigit(line[10]) && line[11] == '\n') skip_next_label = 1;
-
-      if (!strncmp(line + 2, "text\n", 5) ||
-          !strncmp(line + 2, "section\t.text", 13) ||
-          !strncmp(line + 2, "section\t__TEXT,__text", 21) ||
-          !strncmp(line + 2, "section __TEXT,__text", 21)) {
-        instr_ok = 1;
-        continue; 
-      }
-
-      if (!strncmp(line + 2, "section\t", 8) ||
-          !strncmp(line + 2, "section ", 8) ||
-          !strncmp(line + 2, "bss\n", 4) ||
-          !strncmp(line + 2, "data\n", 5)) {
-        instr_ok = 0;
-        continue;
-      }
-
-    }
-
-    /* Detect off-flavor assembly (rare, happens in gdb). When this is
-       encountered, we set skip_csect until the opposite directive is
-       seen, and we do not instrument. */
-
-    if (strstr(line, ".code")) {
-
-      if (strstr(line, ".code32")) skip_csect = use_64bit;
-      if (strstr(line, ".code64")) skip_csect = !use_64bit;
-
-    }
-
-    /* Detect syntax changes, as could happen with hand-written assembly.
-       Skip Intel blocks, resume instrumentation when back to AT&T. */
-
-    if (strstr(line, ".intel_syntax")) skip_intel = 1;
-    if (strstr(line, ".att_syntax")) skip_intel = 0;
-
-    /* Detect and skip ad-hoc __asm__ blocks, likewise skipping them. */
-
-    if (line[0] == '#' || line[1] == '#') {
-
-      if (strstr(line, "#APP")) skip_app = 1;
-      if (strstr(line, "#NO_APP")) skip_app = 0;
-
-    }
-
-    /* If we're in the right mood for instrumenting, check for function
-       names or conditional labels. This is a bit messy, but in essence,
-       we want to catch:
-
-         ^main:      - function entry point (always instrumented)
-         ^.L0:       - GCC branch label
-         ^.LBB0_0:   - clang branch label (but only in clang mode)
-         ^\tjnz foo  - conditional branches
-
-       ...but not:
-
-         ^# BB#0:    - clang comments
-         ^ # BB#0:   - ditto
-         ^.Ltmp0:    - clang non-branch labels
-         ^.LC0       - GCC non-branch labels
-         ^.LBB0_0:   - ditto (when in GCC mode)
-         ^\tjmp foo  - non-conditional jumps
-
-       Additionally, clang and GCC on MacOS X follow a different convention
-       with no leading dots on labels, hence the weird maze of #ifdefs
-       later on.
-
-     */
-
-    if (skip_intel || skip_app || skip_csect || !instr_ok ||
-        line[0] == '#' || line[0] == ' ') continue;
-
-    /* Conditional branch instruction (jnz, etc). We append the instrumentation
-       right after the branch (to instrument the not-taken path) and at the
-       branch destination label (handled later on). */
-
-    if (line[0] == '\t') {
-
-      if (line[1] == 'j' && line[2] != 'm' && R(100) < inst_ratio) {
-
-        fprintf(outf, use_64bit ? trampoline_fmt_64 : trampoline_fmt_32,
-                R(MAP_SIZE));
-
-        ins_lines++;
-
-      }
-
-      continue;
-
-    }
-
-    /* Label of some sort. This may be a branch destination, but we need to
-       read carefully and account for several different formatting
-       conventions. */
-
-#ifdef __APPLE__
-
-    /* Apple: L<whatever><digit>: */
-
-    if ((colon_pos = strstr(line, ":"))) {
-
-      if (line[0] == 'L' && isdigit(*(colon_pos - 1))) {
-
-#else
-
-    /* Everybody else: .L<whatever>: */
-
-    if (strstr(line, ":")) {
-
-      if (line[0] == '.') {
-
-#endif /* __APPLE__ */
-
-        /* .L0: or LBB0_0: style jump destination */
-
-#ifdef __APPLE__
-
-        /* Apple: L<num> / LBB<num> */
-
-        if ((isdigit(line[1]) || (clang_mode && !strncmp(line, "LBB", 3)))
-            && R(100) < inst_ratio) {
-
-#else
-
-        /* Apple: .L<num> / .LBB<num> */
-
-        if ((isdigit(line[2]) || (clang_mode && !strncmp(line + 1, "LBB", 3)))
-            && R(100) < inst_ratio) {
-
-#endif /* __APPLE__ */
-
-          /* An optimization is possible here by adding the code only if the
-             label is mentioned in the code in contexts other than call / jmp.
-             That said, this complicates the code by requiring two-pass
-             processing (messy with stdin), and results in a speed gain
-             typically under 10%, because compilers are generally pretty good
-             about not generating spurious intra-function jumps.
-
-             We use deferred output chiefly to avoid disrupting
-             .Lfunc_begin0-style exception handling calculations (a problem on
-             MacOS X). */
-
-          if (!skip_next_label) instrument_next = 1; else skip_next_label = 0;
-
-        }
-
-      } else {
-
-        /* Function label (always instrumented, deferred mode). */
-
-        instrument_next = 1;
-    
-      }
-
-    }
-
-  }
-
-  if (ins_lines)
-    fputs(use_64bit ? main_payload_64 : main_payload_32, outf);
-
-  if (input_file) fclose(inf);
-  fclose(outf);
-
-  if (!be_quiet) {
-
-    if (!ins_lines) WARNF("No instrumentation targets found%s.",
-                          pass_thru ? " (pass-thru mode)" : "");
-    else OKF("Instrumented %u locations (%s-bit, %s mode, ratio %u%%).",
-             ins_lines, use_64bit ? "64" : "32",
-             getenv("AFL_HARDEN") ? "hardened" : 
-             (sanitizer ? "ASAN/MSAN" : "non-hardened"),
-             inst_ratio);
- 
-  }
-
-}
-
-
-/* Main entry point */
-
-int main(int argc, char** argv) {
-
-  s32 pid;
-  u32 rand_seed;
-  int status;
-  u8* inst_ratio_str = getenv("AFL_INST_RATIO");
-
-  struct timeval tv;
-  struct timezone tz;
-
-  clang_mode = !!getenv(CLANG_ENV_VAR);
-
-  if (isatty(2) && !getenv("AFL_QUIET")) {
-
-    SAYF(cCYA "afl-as" VERSION cRST " by <lcamtuf@google.com>\n");
- 
-  } else be_quiet = 1;
-
-  if (argc < 2) {
-
-    SAYF("\n"
-         "This is a helper application for afl-fuzz. It is a wrapper around GNU 'as',\n"
-         "executed by the toolchain whenever using afl-gcc or afl-clang. You probably\n"
-         "don't want to run this program directly.\n\n"
-
-         "Rarely, when dealing with extremely complex projects, it may be advisable to\n"
-         "set AFL_INST_RATIO to a value less than 100 in order to reduce the odds of\n"
-         "instrumenting every discovered branch.\n\n");
-
-    exit(1);
-
-  }
-
-  gettimeofday(&tv, &tz);
-
-  rand_seed = tv.tv_sec ^ tv.tv_usec ^ getpid();
-
-  srandom(rand_seed);
-
-  edit_params(argc, argv);
-
-  if (inst_ratio_str) {
-
-    if (sscanf(inst_ratio_str, "%u", &inst_ratio) != 1 || inst_ratio > 100) 
-      FATAL("Bad value of AFL_INST_RATIO (must be between 0 and 100)");
-
-  }
-
-  if (getenv(AS_LOOP_ENV_VAR))
-    FATAL("Endless loop when calling 'as' (remove '.' from your PATH)");
-
-  setenv(AS_LOOP_ENV_VAR, "1", 1);
-
-  /* When compiling with ASAN, we don't have a particularly elegant way to skip
-     ASAN-specific branches. But we can probabilistically compensate for
-     that... */
-
-  if (getenv("AFL_USE_ASAN") || getenv("AFL_USE_MSAN")) {
-    sanitizer = 1;
-    if (!getenv("AFL_INST_RATIO"))
-      inst_ratio /= 3;
-  }
-
-  if (!just_version) add_instrumentation();
-
-  if (!(pid = fork())) {
-
-    execvp(as_params[0], (char**)as_params);
-    FATAL("Oops, failed to execute '%s' - check your PATH", as_params[0]);
-
-  }
-
-  if (pid < 0) PFATAL("fork() failed");
-
-  if (waitpid(pid, &status, 0) <= 0) PFATAL("waitpid() failed");
-
-  if (!getenv("AFL_KEEP_ASSEMBLY")) unlink(modified_file);
-
-  exit(WEXITSTATUS(status));
-
-}
-