GRR is an x86 to amd64 binary translator. GRR was created to emulate and fuzz DECREE challenge binaries.
- Code cache persistence (avoids translation overheads across separate runs).
- Optimization of the code cache, including the persisted cache.
- Multi-processing support (allows multiple communicating, 32-bit processes to be emulated within a single 64-bit address space).
- Built-in fuzzing engine, which includes Radamsa.
- Support for self-modifying code (e.g. JIT compilers). Self-modified code can also be persisted.
- Orchestration. GRR does not manage a fuzzing campaign. An external orchestration system can direct GRR to fuzz a program, and identify a minimal set of maximal coverage-producing inputs.
Install System dependcies
sudo apt-get install -y git build-essential sudo apt-get install -y clang llvm-dev libc++1 libc++-dev
Then we can build GRR. This script will create
grr-build in the current
working directory, and download remaining dependencies.
There are two steps to running GRR: snapshotting, and record/replaying. Snapshotting creates an initial image of the binary after
execve. Record/replaying takes an input testcase and attempts to replay that testcase. The replay can be recorded or mutated as well.
You can run
grrshot on a CGC challenge binary, or on a statically linked 32-bit ELF version of a CGC challenge binary.
./bin/debug_linux_user/grrshot --num_exe=1 --exe_dir=/path --exe_prefix=CADET_000 --snapshot_dir=/tmp/snapshot
This will create a snapshot of
/path/CADET_00001 and store the snapshot into the
./bin/debug_linux_user/grrplay --num_exe=1 --snapshot_dir=/tmp/snapshot --persist_dir=/tmp/persist --input=/path/to/testcase
Replay + Recording
./bin/debug_linux_user/grrplay --num_exe=1 --snapshot_dir=/tmp/snapshot --persist_dir=/tmp/persist --input=/path/to/testcase --output_dir=/tmp/out
Replay + Recording + Mutating
./bin/debug_linux_user/grrplay --num_exe=1 --snapshot_dir=/tmp/snapshot --persist_dir=/tmp/persist --input=/path/to/testcase --output_dir=/tmp/out --input_mutator=inf_radamsa_spliced
There are many mutators. Some of the mutators are deterministic, and therefore run for a period of time that is proportional to the number of
receive system calls in the input testcase. Other mutators are non-deterministic and can run forever. These mutators are prefixed with
GRR depends on gflags.
GRR depends on Frank Thilo's C++ port of the the RSA Data Security, Inc. MD5 Message-Digest Algorithm.
GRR uses Yann Collet's xxHash as part of its code cache index hash table.
GRR was created for the DARPA Cyber Grand Challenge. It was an essential component of Trail of Bit's CRS. The version of GRR in this repository differs from the CRS version in some important ways.