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authorAndrea Fioraldi <andreafioraldi@gmail.com>2020-02-03 13:11:10 +0100
committerAndrea Fioraldi <andreafioraldi@gmail.com>2020-02-03 13:11:10 +0100
commit2fe7889912c9bb340f302a037585b7b1836ac94f (patch)
tree5c3e4e5829f45dce46794ebc2681732738d689fe /experimental/post_library
parente2eedefc65bec1a04605f117a11ca8bdf9d80323 (diff)
downloadafl++-2fe7889912c9bb340f302a037585b7b1836ac94f.tar.gz
move custom and pythoon mutators examples into examples/
Diffstat (limited to 'experimental/post_library')
-rw-r--r--experimental/post_library/post_library.so.c120
-rw-r--r--experimental/post_library/post_library_png.so.c114
2 files changed, 0 insertions, 234 deletions
diff --git a/experimental/post_library/post_library.so.c b/experimental/post_library/post_library.so.c
deleted file mode 100644
index 487b9a6d..00000000
--- a/experimental/post_library/post_library.so.c
+++ /dev/null
@@ -1,120 +0,0 @@
-/*
-   american fuzzy lop++ - postprocessor library example
-   --------------------------------------------------
-
-   Originally written by Michal Zalewski
-
-   Copyright 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
-
-   Postprocessor libraries can be passed to afl-fuzz to perform final cleanup
-   of any mutated test cases - for example, to fix up checksums in PNG files.
-
-   Please heed the following warnings:
-
-   1) In almost all cases, it is more productive to comment out checksum logic
-      in the targeted binary (as shown in ../libpng_no_checksum/). One possible
-      exception is the process of fuzzing binary-only software in QEMU mode.
-
-   2) The use of postprocessors for anything other than checksums is
-   questionable and may cause more harm than good. AFL is normally pretty good
-   about dealing with length fields, magic values, etc.
-
-   3) Postprocessors that do anything non-trivial must be extremely robust to
-      gracefully handle malformed data and other error conditions - otherwise,
-      they will crash and take afl-fuzz down with them. Be wary of reading past
-      *len and of integer overflows when calculating file offsets.
-
-   In other words, THIS IS PROBABLY NOT WHAT YOU WANT - unless you really,
-   honestly know what you're doing =)
-
-   With that out of the way: the postprocessor library is passed to afl-fuzz
-   via AFL_POST_LIBRARY. The library must be compiled with:
-
-     gcc -shared -Wall -O3 post_library.so.c -o post_library.so
-
-   AFL will call the afl_postprocess() function for every mutated output buffer.
-   From there, you have three choices:
-
-   1) If you don't want to modify the test case, simply return the original
-      buffer pointer ('in_buf').
-
-   2) If you want to skip this test case altogether and have AFL generate a
-      new one, return NULL. Use this sparingly - it's faster than running
-      the target program with patently useless inputs, but still wastes CPU
-      time.
-
-   3) If you want to modify the test case, allocate an appropriately-sized
-      buffer, move the data into that buffer, make the necessary changes, and
-      then return the new pointer. You can update *len if necessary, too.
-
-      Note that the buffer will *not* be freed for you. To avoid memory leaks,
-      you need to free it or reuse it on subsequent calls (as shown below).
-
-      *** DO NOT MODIFY THE ORIGINAL 'in_buf' BUFFER. ***
-
-    Aight. The example below shows a simple postprocessor that tries to make
-    sure that all input files start with "GIF89a".
-
-    PS. If you don't like C, you can try out the unix-based wrapper from
-    Ben Nagy instead: https://github.com/bnagy/aflfix
-
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-/* Header that must be present at the beginning of every test case: */
-
-#define HEADER "GIF89a"
-
-/* The actual postprocessor routine called by afl-fuzz: */
-
-const unsigned char* afl_postprocess(const unsigned char* in_buf,
-                                     unsigned int*        len) {
-
-  static unsigned char* saved_buf;
-  unsigned char*        new_buf;
-
-  /* Skip execution altogether for buffers shorter than 6 bytes (just to
-     show how it's done). We can trust *len to be sane. */
-
-  if (*len < strlen(HEADER)) return NULL;
-
-  /* Do nothing for buffers that already start with the expected header. */
-
-  if (!memcmp(in_buf, HEADER, strlen(HEADER))) return in_buf;
-
-  /* Allocate memory for new buffer, reusing previous allocation if
-     possible. */
-
-  new_buf = realloc(saved_buf, *len);
-
-  /* If we're out of memory, the most graceful thing to do is to return the
-     original buffer and give up on modifying it. Let AFL handle OOM on its
-     own later on. */
-
-  if (!new_buf) return in_buf;
-  saved_buf = new_buf;
-
-  /* Copy the original data to the new location. */
-
-  memcpy(new_buf, in_buf, *len);
-
-  /* Insert the new header. */
-
-  memcpy(new_buf, HEADER, strlen(HEADER));
-
-  /* Return modified buffer. No need to update *len in this particular case,
-     as we're not changing it. */
-
-  return new_buf;
-
-}
-
diff --git a/experimental/post_library/post_library_png.so.c b/experimental/post_library/post_library_png.so.c
deleted file mode 100644
index 43cb1101..00000000
--- a/experimental/post_library/post_library_png.so.c
+++ /dev/null
@@ -1,114 +0,0 @@
-/*
-   american fuzzy lop++ - postprocessor for PNG
-   ------------------------------------------
-
-   Originally written by Michal Zalewski
-
-   Copyright 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
-
-   See post_library.so.c for a general discussion of how to implement
-   postprocessors. This specific postprocessor attempts to fix up PNG
-   checksums, providing a slightly more complicated example than found
-   in post_library.so.c.
-
-   Compile with:
-
-     gcc -shared -Wall -O3 post_library_png.so.c -o post_library_png.so -lz
-
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <string.h>
-#include <zlib.h>
-
-#include <arpa/inet.h>
-
-/* A macro to round an integer up to 4 kB. */
-
-#define UP4K(_i) ((((_i) >> 12) + 1) << 12)
-
-const unsigned char* afl_postprocess(const unsigned char* in_buf,
-                                     unsigned int*        len) {
-
-  static unsigned char* saved_buf;
-  static unsigned int   saved_len;
-
-  unsigned char* new_buf = (unsigned char*)in_buf;
-  unsigned int   pos = 8;
-
-  /* Don't do anything if there's not enough room for the PNG header
-     (8 bytes). */
-
-  if (*len < 8) return in_buf;
-
-  /* Minimum size of a zero-length PNG chunk is 12 bytes; if we
-     don't have that, we can bail out. */
-
-  while (pos + 12 <= *len) {
-
-    unsigned int chunk_len, real_cksum, file_cksum;
-
-    /* Chunk length is the first big-endian dword in the chunk. */
-
-    chunk_len = ntohl(*(uint32_t*)(in_buf + pos));
-
-    /* Bail out if chunk size is too big or goes past EOF. */
-
-    if (chunk_len > 1024 * 1024 || pos + 12 + chunk_len > *len) break;
-
-    /* Chunk checksum is calculated for chunk ID (dword) and the actual
-       payload. */
-
-    real_cksum = htonl(crc32(0, in_buf + pos + 4, chunk_len + 4));
-
-    /* The in-file checksum is the last dword past the chunk data. */
-
-    file_cksum = *(uint32_t*)(in_buf + pos + 8 + chunk_len);
-
-    /* If the checksums do not match, we need to fix the file. */
-
-    if (real_cksum != file_cksum) {
-
-      /* First modification? Make a copy of the input buffer. Round size
-         up to 4 kB to minimize the number of reallocs needed. */
-
-      if (new_buf == in_buf) {
-
-        if (*len <= saved_len) {
-
-          new_buf = saved_buf;
-
-        } else {
-
-          new_buf = realloc(saved_buf, UP4K(*len));
-          if (!new_buf) return in_buf;
-          saved_buf = new_buf;
-          saved_len = UP4K(*len);
-          memcpy(new_buf, in_buf, *len);
-
-        }
-
-      }
-
-      *(uint32_t*)(new_buf + pos + 8 + chunk_len) = real_cksum;
-
-    }
-
-    /* Skip the entire chunk and move to the next one. */
-
-    pos += 12 + chunk_len;
-
-  }
-
-  return new_buf;
-
-}
-