diff options
author | Andrea Fioraldi <andreafioraldi@gmail.com> | 2019-08-30 11:38:33 +0200 |
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committer | Andrea Fioraldi <andreafioraldi@gmail.com> | 2019-08-30 11:38:33 +0200 |
commit | 7b36afd5f16894257c92695d200e59eb51d08e1c (patch) | |
tree | 26fd741ab05512ca079a3bd0ba84039607066f60 /unicorn_mode | |
parent | f677427f681b0297ce7d9ed4967380a09e59e363 (diff) | |
download | AFLplusplus-7b36afd5f16894257c92695d200e59eb51d08e1c.tar.gz |
modernize docs and readme for qemu and unicorn
Diffstat (limited to 'unicorn_mode')
-rw-r--r-- | unicorn_mode/README.md | 130 | ||||
-rwxr-xr-x | unicorn_mode/build_unicorn_support.sh | 12 | ||||
-rw-r--r-- | unicorn_mode/patches/afl-unicorn-common.h | 18 | ||||
-rw-r--r-- | unicorn_mode/patches/afl-unicorn-cpu-inl.h | 18 | ||||
-rw-r--r-- | unicorn_mode/patches/afl-unicorn-cpu-translate-inl.h | 18 | ||||
-rw-r--r-- | unicorn_mode/patches/afl-unicorn-tcg-op-inl.h | 18 | ||||
-rw-r--r-- | unicorn_mode/patches/afl-unicorn-tcg-runtime-inl.h | 18 | ||||
-rw-r--r-- | unicorn_mode/samples/compcov_x64/COMPILE.md | 3 | ||||
-rw-r--r-- | unicorn_mode/samples/compcov_x64/compcov_target.c | 2 | ||||
-rw-r--r-- | unicorn_mode/samples/simple/COMPILE.md | 5 |
10 files changed, 170 insertions, 72 deletions
diff --git a/unicorn_mode/README.md b/unicorn_mode/README.md index 9ee975ef..ea3e3c9b 100644 --- a/unicorn_mode/README.md +++ b/unicorn_mode/README.md @@ -1,23 +1,119 @@ -``` - __ _ _ - __ _ / _| | _ _ _ __ (_) ___ ___ _ __ _ __ - / _` | |_| |___| | | | '_ \| |/ __/ _ \| '__| '_ \ -| (_| | _| |___| |_| | | | | | (_| (_) | | | | | | - \__,_|_| |_| \__,_|_| |_|_|\___\___/|_| |_| |_| - -``` +# Unicorn-based binary-only instrumentation for afl-fuzz -afl-unicorn lets you fuzz any piece of binary that can be emulated by -[Unicorn Engine](http://www.unicorn-engine.org/). +The idea and much of the original implementation comes from Nathan Voss <njvoss299@gmail.com>. -Requirements: Python2 +The port to afl++ if by Dominik Maier <mail@dmnk.co>. -For the full readme please see docs/unicorn_mode.txt +The CompareCoverage and NeverZero counters features by Andrea Fioraldi <andreafioraldi@gmail.com>. -For an in-depth description of what this is, how to install it, and how to use -it check out this [blog post](https://medium.com/@njvoss299/afl-unicorn-fuzzing-arbitrary-binary-code-563ca28936bf). +## 1) Introduction -For general help with AFL, please refer to the documents in the ./docs/ directory. +The code in ./unicorn_mode allows you to build a standalone feature that +leverages the Unicorn Engine and allows callers to obtain instrumentation +output for black-box, closed-source binary code snippets. This mechanism +can be then used by afl-fuzz to stress-test targets that couldn't be built +with afl-gcc or used in QEMU mode, or with other extensions such as +TriforceAFL. -Created by Nathan Voss, originally funded by -[Battelle](https://www.battelle.org/cyber). +There is a significant performance penalty compared to native AFL, +but at least we're able to use AFL on these binaries, right? + +## 2) How to use + +Requirements: you need an installed python2 environment. + +### Building AFL's Unicorn Mode + +First, make afl++ as usual. +Once that completes successfully you need to build and add in the Unicorn Mode +features: + + $ cd unicorn_mode + $ ./build_unicorn_support.sh + +NOTE: This script downloads a Unicorn Engine commit that has been tested +and is stable-ish from the Unicorn github page. If you are offline, you'll need +to hack up this script a little bit and supply your own copy of Unicorn's latest +stable release. It's not very hard, just check out the beginning of the +build_unicorn_support.sh script and adjust as necessary. + +Building Unicorn will take a little bit (~5-10 minutes). Once it completes +it automatically compiles a sample application and verify that it works. + +### Fuzzing with Unicorn Mode + +To really use unicorn-mode effectively you need to prepare the following: + + * Relevant binary code to be fuzzed + * Knowledge of the memory map and good starting state + * Folder containing sample inputs to start fuzzing with + + Same ideas as any other AFL inputs + + Quality/speed of results will depend greatly on quality of starting + samples + + See AFL's guidance on how to create a sample corpus + * Unicorn-based test harness which: + + Adds memory map regions + + Loads binary code into memory + + Emulates at least one instruction* + + Yeah, this is lame. See 'Gotchas' section below for more info + + Loads and verifies data to fuzz from a command-line specified file + + AFL will provide mutated inputs by changing the file passed to + the test harness + + Presumably the data to be fuzzed is at a fixed buffer address + + If input constraints (size, invalid bytes, etc.) are known they + should be checked after the file is loaded. If a constraint + fails, just exit the test harness. AFL will treat the input as + 'uninteresting' and move on. + + Sets up registers and memory state for beginning of test + + Emulates the interested code from beginning to end + + If a crash is detected, the test harness must 'crash' by + throwing a signal (SIGSEGV, SIGKILL, SIGABORT, etc.) + +Once you have all those things ready to go you just need to run afl-fuzz in +'unicorn-mode' by passing in the '-U' flag: + + $ afl-fuzz -U -m none -i /path/to/inputs -o /path/to/results -- ./test_harness @@ + +The normal afl-fuzz command line format applies to everything here. Refer to +AFL's main documentation for more info about how to use afl-fuzz effectively. + +For a much clearer vision of what all of this looks like, please refer to the +sample provided in the 'unicorn_mode/samples' directory. There is also a blog +post that goes over the basics at: + +https://medium.com/@njvoss299/afl-unicorn-fuzzing-arbitrary-binary-code-563ca28936bf + +The 'helper_scripts' directory also contains several helper scripts that allow you +to dump context from a running process, load it, and hook heap allocations. For details +on how to use this check out the follow-up blog post to the one linked above. + +A example use of AFL-Unicorn mode is discussed in the Paper Unicorefuzz: +https://www.usenix.org/conference/woot19/presentation/maier + +## 3) Options + +As for the QEMU-based instrumentation, the afl-unicorn twist of afl++ +comes with a sub-instruction based instrumentation similar in purpose to laf-intel. + +The options that enables Unicorn CompareCoverage are the same used for QEMU. +AFL_COMPCOV_LEVEL=1 is to instrument comparisons with only immediate +values. QEMU_COMPCOV_LEVEL=2 instruments all +comparison instructions. Comparison instructions are currently instrumented only +on the x86 and x86_64 targets. + +## 4) Gotchas, feedback, bugs + +To make sure that AFL's fork server starts up correctly the Unicorn test +harness script must emulate at least one instruction before loading the +data that will be fuzzed from the input file. It doesn't matter what the +instruction is, nor if it is valid. This is an artifact of how the fork-server +is started and could likely be fixed with some clever re-arranging of the +patches applied to Unicorn. + +Running the build script builds Unicorn and its python bindings and installs +them on your system. This installation will supersede any existing Unicorn +installation with the patched afl-unicorn version. + +Refer to the unicorn_mode/samples/arm_example/arm_tester.c for an example +of how to do this properly! If you don't get this right, AFL will not +load any mutated inputs and your fuzzing will be useless! diff --git a/unicorn_mode/build_unicorn_support.sh b/unicorn_mode/build_unicorn_support.sh index 2c0fe4b1..1575f66c 100755 --- a/unicorn_mode/build_unicorn_support.sh +++ b/unicorn_mode/build_unicorn_support.sh @@ -1,16 +1,20 @@ #!/bin/sh # -# american fuzzy lop - Unicorn-Mode build script -# -------------------------------------- +# american fuzzy lop++ - unicorn mode build script +# ------------------------------------------------ # -# Written by Nathan Voss <njvoss99@gmail.com> +# Originally written by Nathan Voss <njvoss99@gmail.com> # # Adapted from code by Andrew Griffiths <agriffiths@google.com> and # Michal Zalewski <lcamtuf@google.com> # -# Adapted for Afl++ by Dominik Maier <mail@dmnk.co> +# Adapted for AFLplusplus by Dominik Maier <mail@dmnk.co> +# +# CompareCoverage and NeverZero counters by Andrea Fioraldi +# <andreafioraldi@gmail.com> # # Copyright 2017 Battelle Memorial Institute. All rights reserved. +# Copyright 2019 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. diff --git a/unicorn_mode/patches/afl-unicorn-common.h b/unicorn_mode/patches/afl-unicorn-common.h index 9a1b2a6c..6798832c 100644 --- a/unicorn_mode/patches/afl-unicorn-common.h +++ b/unicorn_mode/patches/afl-unicorn-common.h @@ -1,17 +1,17 @@ /* - american fuzzy lop - high-performance binary-only instrumentation - ----------------------------------------------------------------- + american fuzzy lop++ - unicorn instrumentation + ---------------------------------------------- - Written by Andrew Griffiths <agriffiths@google.com> and - Michal Zalewski <lcamtuf@google.com> + Originally written by Andrew Griffiths <agriffiths@google.com> and + Michal Zalewski <lcamtuf@google.com> - TCG instrumentation and block chaining support by Andrea Biondo - <andrea.biondo965@gmail.com> Adapted for afl-unicorn by Dominik Maier <mail@dmnk.co> - Idea & design very much by Andrew Griffiths. + CompareCoverage and NeverZero counters by Andrea Fioraldi + <andreafioraldi@gmail.com> - Copyright 2015, 2016 Google Inc. All rights reserved. + Copyright 2015, 2016, 2017 Google Inc. All rights reserved. + Copyright 2019 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. @@ -24,7 +24,7 @@ to implement AFL-style instrumentation and to take care of the remaining parts of the AFL fork server logic. - The resulting QEMU binary is essentially a standalone instrumentation + The resulting libunicorn binary is essentially a standalone instrumentation tool; for an example of how to leverage it for other purposes, you can have a look at afl-showmap.c. diff --git a/unicorn_mode/patches/afl-unicorn-cpu-inl.h b/unicorn_mode/patches/afl-unicorn-cpu-inl.h index 90937a17..a713e4ca 100644 --- a/unicorn_mode/patches/afl-unicorn-cpu-inl.h +++ b/unicorn_mode/patches/afl-unicorn-cpu-inl.h @@ -1,17 +1,17 @@ /* - american fuzzy lop - high-performance binary-only instrumentation - ----------------------------------------------------------------- + american fuzzy lop++ - unicorn instrumentation + ---------------------------------------------- - Written by Andrew Griffiths <agriffiths@google.com> and - Michal Zalewski <lcamtuf@google.com> + Originally written by Andrew Griffiths <agriffiths@google.com> and + Michal Zalewski <lcamtuf@google.com> - TCG instrumentation and block chaining support by Andrea Biondo - <andrea.biondo965@gmail.com> Adapted for afl-unicorn by Dominik Maier <mail@dmnk.co> - Idea & design very much by Andrew Griffiths. + CompareCoverage and NeverZero counters by Andrea Fioraldi + <andreafioraldi@gmail.com> - Copyright 2015, 2016 Google Inc. All rights reserved. + Copyright 2015, 2016, 2017 Google Inc. All rights reserved. + Copyright 2019 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. @@ -24,7 +24,7 @@ to implement AFL-style instrumentation and to take care of the remaining parts of the AFL fork server logic. - The resulting QEMU binary is essentially a standalone instrumentation + The resulting libunicorn binary is essentially a standalone instrumentation tool; for an example of how to leverage it for other purposes, you can have a look at afl-showmap.c. diff --git a/unicorn_mode/patches/afl-unicorn-cpu-translate-inl.h b/unicorn_mode/patches/afl-unicorn-cpu-translate-inl.h index 7e8f47c9..69877c6b 100644 --- a/unicorn_mode/patches/afl-unicorn-cpu-translate-inl.h +++ b/unicorn_mode/patches/afl-unicorn-cpu-translate-inl.h @@ -1,17 +1,17 @@ /* - american fuzzy lop - high-performance binary-only instrumentation - ----------------------------------------------------------------- + american fuzzy lop++ - unicorn instrumentation + ---------------------------------------------- - Written by Andrew Griffiths <agriffiths@google.com> and - Michal Zalewski <lcamtuf@google.com> + Originally written by Andrew Griffiths <agriffiths@google.com> and + Michal Zalewski <lcamtuf@google.com> - TCG instrumentation and block chaining support by Andrea Biondo - <andrea.biondo965@gmail.com> Adapted for afl-unicorn by Dominik Maier <mail@dmnk.co> - Idea & design very much by Andrew Griffiths. + CompareCoverage and NeverZero counters by Andrea Fioraldi + <andreafioraldi@gmail.com> - Copyright 2015, 2016 Google Inc. All rights reserved. + Copyright 2015, 2016, 2017 Google Inc. All rights reserved. + Copyright 2019 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. @@ -24,7 +24,7 @@ to implement AFL-style instrumentation and to take care of the remaining parts of the AFL fork server logic. - The resulting QEMU binary is essentially a standalone instrumentation + The resulting libunicorn binary is essentially a standalone instrumentation tool; for an example of how to leverage it for other purposes, you can have a look at afl-showmap.c. diff --git a/unicorn_mode/patches/afl-unicorn-tcg-op-inl.h b/unicorn_mode/patches/afl-unicorn-tcg-op-inl.h index d5a29cce..fa4974d6 100644 --- a/unicorn_mode/patches/afl-unicorn-tcg-op-inl.h +++ b/unicorn_mode/patches/afl-unicorn-tcg-op-inl.h @@ -1,17 +1,17 @@ /* - american fuzzy lop - high-performance binary-only instrumentation - ----------------------------------------------------------------- + american fuzzy lop++ - unicorn instrumentation + ---------------------------------------------- - Written by Andrew Griffiths <agriffiths@google.com> and - Michal Zalewski <lcamtuf@google.com> + Originally written by Andrew Griffiths <agriffiths@google.com> and + Michal Zalewski <lcamtuf@google.com> - TCG instrumentation and block chaining support by Andrea Biondo - <andrea.biondo965@gmail.com> Adapted for afl-unicorn by Dominik Maier <mail@dmnk.co> - Idea & design very much by Andrew Griffiths. + CompareCoverage and NeverZero counters by Andrea Fioraldi + <andreafioraldi@gmail.com> - Copyright 2015, 2016 Google Inc. All rights reserved. + Copyright 2015, 2016, 2017 Google Inc. All rights reserved. + Copyright 2019 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. @@ -24,7 +24,7 @@ to implement AFL-style instrumentation and to take care of the remaining parts of the AFL fork server logic. - The resulting QEMU binary is essentially a standalone instrumentation + The resulting libunicorn binary is essentially a standalone instrumentation tool; for an example of how to leverage it for other purposes, you can have a look at afl-showmap.c. diff --git a/unicorn_mode/patches/afl-unicorn-tcg-runtime-inl.h b/unicorn_mode/patches/afl-unicorn-tcg-runtime-inl.h index 0019bbfa..1f0667ce 100644 --- a/unicorn_mode/patches/afl-unicorn-tcg-runtime-inl.h +++ b/unicorn_mode/patches/afl-unicorn-tcg-runtime-inl.h @@ -1,17 +1,17 @@ /* - american fuzzy lop - high-performance binary-only instrumentation - ----------------------------------------------------------------- + american fuzzy lop++ - unicorn instrumentation + ---------------------------------------------- - Written by Andrew Griffiths <agriffiths@google.com> and - Michal Zalewski <lcamtuf@google.com> + Originally written by Andrew Griffiths <agriffiths@google.com> and + Michal Zalewski <lcamtuf@google.com> - TCG instrumentation and block chaining support by Andrea Biondo - <andrea.biondo965@gmail.com> Adapted for afl-unicorn by Dominik Maier <mail@dmnk.co> - Idea & design very much by Andrew Griffiths. + CompareCoverage and NeverZero counters by Andrea Fioraldi + <andreafioraldi@gmail.com> - Copyright 2015, 2016 Google Inc. All rights reserved. + Copyright 2015, 2016, 2017 Google Inc. All rights reserved. + Copyright 2019 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. @@ -24,7 +24,7 @@ to implement AFL-style instrumentation and to take care of the remaining parts of the AFL fork server logic. - The resulting QEMU binary is essentially a standalone instrumentation + The resulting libunicorn binary is essentially a standalone instrumentation tool; for an example of how to leverage it for other purposes, you can have a look at afl-showmap.c. diff --git a/unicorn_mode/samples/compcov_x64/COMPILE.md b/unicorn_mode/samples/compcov_x64/COMPILE.md index db488d30..35de7ad8 100644 --- a/unicorn_mode/samples/compcov_x64/COMPILE.md +++ b/unicorn_mode/samples/compcov_x64/COMPILE.md @@ -1,5 +1,4 @@ -Compiling compcov_target.c -========================== +# Compiling compcov_target.c compcov_target.c was compiled without optimization, position-independent, and without standard libraries using the following command line: diff --git a/unicorn_mode/samples/compcov_x64/compcov_target.c b/unicorn_mode/samples/compcov_x64/compcov_target.c index 71b4cb0e..eb1205b1 100644 --- a/unicorn_mode/samples/compcov_x64/compcov_target.c +++ b/unicorn_mode/samples/compcov_x64/compcov_target.c @@ -7,7 +7,7 @@ * (0x00300000), so make sure that your Unicorn emulation of this * puts user data there. * - * Written by Nathan Voss <njvoss99@gmail.com> + * Written by Andrea Fioraldi */ // Magic address where mutated data will be placed diff --git a/unicorn_mode/samples/simple/COMPILE.md b/unicorn_mode/samples/simple/COMPILE.md index bd4a66c6..f7bf5b50 100644 --- a/unicorn_mode/samples/simple/COMPILE.md +++ b/unicorn_mode/samples/simple/COMPILE.md @@ -1,5 +1,4 @@ -Compiling simple_target.c -========================== +# Compiling simple_target.c You shouldn't need to compile simple_target.c since a MIPS binary version is pre-built and shipped with afl-unicorn. This file documents how the binary @@ -38,4 +37,4 @@ mips-linux-gnu-gcc -o simple_target.elf simple_target.c -fPIC -O0 -nostdlib Note that the output of this is padded with nulls for 16-byte alignment. This is important when emulating it, as NOPs will be added after the return of main() -as necessary.
\ No newline at end of file +as necessary. |