Code repository for "Retrowrite: Statically Instrumenting COTS Binaries for Fuzzing and Sanitization" (in IEEE S&P'20). Please refer to the paper for technical details. There's also a 36c3 presentation and 36c3 video to get you started.
This project contains 2 different version of retrowrite :
- Retrowrite to rewrite classic userspace binaries, and
- KRetrowrite to rewrite and fuzz kernel modules.
The two versions can be used independently of each other or at the same time. In case you want to use both please follow the instructions for KRetrowrite.
Retrowrite is implemented in python3 (3.6). Make sure python3 and python3-venv is installed on system. Retrowrite depends on capstone. The version available from the Ubuntu 18.04 repositories is not compatible with this version. The setup script pulls the latest version of capstone from the repository and builds it. Make sure that your system meets the requirements to build capstone.
The target binary
- must be compiled as position independent code (PIC/PIE)
- must be x86_64 (32 bit at your own risk)
- must contain symbols (i.e., not stripped; if stripped, please recover symbols first)
- must not contain C++ exceptions (i.e., C++ exception tables are not recovered and simply stripped during lifting)
The individual tools also have command line help which describes all the
options, and may be accessed with -h.
To start with use retrowrite command:
(retro) $ retrowrite --help
usage: retrowrite [-h] [-a] [-s] [-k] [--kcov] [-c] bin outfile
positional arguments:
bin Input binary to load
outfile Symbolized ASM output
optional arguments:
-h, --help show this help message and exit
-a, --asan Add binary address sanitizer instrumentation
-s, --assembly Generate Symbolized Assembly
-k, --kernel Instrument a kernel module
--kcov Instrument the kernel module with kcov
-c, --cache Save/load register analysis cache (only used with --asan)
--ignore-no-pie Ignore position-independent-executable check (use with
caution)
--ignore-stripped Ignore stripped executable check (use with caution)
In case you load a non position independent code you will get the following message:
(retro) $ retrowrite stack stack.c
***** RetroWrite requires a position-independent executable. *****
It looks like stack is not position independent
If you really want to continue, because you think retrowrite has made a mistake, pass --ignore-no-pie.
In the case you think retrowrite is mistaking you can use the argument --ignore-no-pie.
This section highlights the steps to get you up to speed to use userspace retrowrite for rewriting PIC binaries.
Retrowrite ships with an utility with the following features:
- Generate symbolized assembly files from binaries without source code
- BASan: Instrument binary with binary-only Address Sanitizer
- Support for symbolizing (linux) kernel modules
- KCovariance instrumentation support
Run setup.sh:
./setup.sh user
Activate the virtualenv (from root of the repository):
source retro/bin/activate
(Bonus) To exit virtualenv when you're done with retrowrite:
deactivate
retrowrite --asan </path/to/binary/> </path/to/output/binary>
Note: Make sure that the binary is position-independent and is not stripped.
This can be checked using file command (the output should say ELF shared object).
Example, create an instrumented version of /bin/ls:
retrowrite --asan /bin/ls ls-basan-instrumented
This will generate an assembly (.s) file that can be assembled and linked
using any compiler, example:
gcc ls-basan-instrumented.s -lasan -o ls-basan-instrumented
debug in case you get the error undefined reference to `__asan_init_v4' ,
replace "asan_init_v4" by "asan_init" in the assembly file, the following command can help you do that:
sed -i 's/asan_init_v4/asan_init/g' ls-basan-instrumented.s
To generate symbolized assembly that may be modified by hand or post-processed by existing tools:
retrowrite </path/to/binary> <path/to/output/asm/files>
Post-modification, the asm files may be assembled to working binaries as described above.
While retrowrite is interoperable with other tools, we strongly encourage researchers to use the retrowrite API for their binary instrumentation / modification needs! This saves the additional effort of having to load and parse binaries or assembly files. Check the developer sections for more details on getting started.
To generate an AFL instrumented binary, first generate the symbolized assembly
as described above. Then, recompile the symbolized assembly with afl-gcc from
afl++ like this:
$ AFL_AS_FORCE_INSTRUMENT=1 afl-gcc foo.s -o foo
or afl-clang.
See fuzzing/docker for more information on building a docker image for fuzzing and reproducing results.
Run setup.sh:
./setup.sh kernel
Activate the virtualenv (from root of the repository):
source retro/bin/activate
(Bonus) To exit virtualenv when you're done with retrowrite:
deactivate
- Instrument Binary with Binary-Address Sanitizer (BASan) :
retrowrite --asan --kernel </path/to/module.ko> </path/to/output/module_asan.ko> - Generate Symbolized Assembly that may be modified by hand or post-processed by existing tools:
retrowrite </path/to/module.ko> <path/to/output/asm/files>
For fuzzing campaign please see fuzzing/ folder.
In general, librw/ contains the code for loading, disassembly, and
symbolization of binaries and forms the core of all transformations.
Individual transformation passes that build on top this rewriting framework,
such as our binary-only Address Sanitizer (BASan) is contained as individual
tools in rwtools/.
The files and folder starting with k are linked with the kernel retrowrite version.
In the demos/ folder, you will find examples for userspace and kernel retrowrite (demos/user_demo and demos/kernel_demo respectively).
The following publications cover different parts of the RetroWrite project:
-
RetroWrite: Statically Instrumenting COTS Binaries for Fuzzing and Sanitization Sushant Dinesh, Nathan Burow, Dongyan Xu, and Mathias Payer. In Oakland'20: IEEE International Symposium on Security and Privacy, 2020
-
No source, no problem! High speed binary fuzzing Matteo Rizzo, and Mathias Payer. In 36c3'19: Chaos Communication Congress, 2019
The MIT License
Copyright (c) 2019 HexHive Group, Sushant Dinesh sushant.dinesh94@gmail.com, Matteo Rizzo matteorizzo.personal@gmail.com, Mathias Payer mathias.payer@nebelwelt.net
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
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