This repository contains several modified versions of AFL components which we utilize in our experiments on fixed (pre-generated) fuzzing input datasets:

• afl-saveinputs - dumps AFL-generated inputs and their sizes to file (for fixed input dataset experiments).
• afl-testtrace - evaluates any tracer's (e.g., QEMU, Dyninst) execution time on a fixed input dataset.
• afl-cc forkserver-only extension - inserts only a forkserver during AFL's assembly-time instrumentation (useful for benchmarking).

git clone https://github.com/FoRTE-Research/afl-fid
cd afl
make all

sudo apt-get install libtool-bin libglib2.0-dev automake flex bison
cd afl-fid/qemu_mode_v1
sudo ./build_qemu_support.sh
chmod +x ../afl-qemu-trace

Note the following:

• The build may finish with an error even though afl-qemu-trace was built correctly. We recommend checking a few build status messages in the log to determine if the build was successful.
• For running with the optimized QEMU with block chaining enabled, build instead from qemu_mode_v2. When running afl-saveinputs or afl-testtrace, replace -Q with -QQ.

afl-saveinputs is a modified version of afl-fuzz for dumping generated inputs to file. Usage is as follows:

afl-saveinputs -i [/path/to/seed_dir] -o [/path/to/out_dir] -e [time budget (# minutes)] [optional_args] -Q -- [/path/to/target] [target_args]

Input dump and sizes will be stored in out_dir/_INPUT_DUMP and out_dir/_INPUT_SIZES, respectively.

• Note: QEMU mode is recommended, otherwise dumps may be explosively large in size (depending on fuzzing speed).

afl-testtrace is an afl-fuzz modification for logging each fuzzed input's tracing time. Given an input dump and corresponding sizes file (produced by afl-saveinputs), It recreates each input and logs its execution (function run_target() in afl-fuzz) time. Usage is as follows:

afl-testrace -i [/path/to/input/data/dump] -s [/path/to/input/sizes/dump] -o [/path/to/outdir] -f [/path/to/outfile] -c [max execs | skip for full dump] -t [exec timeout | skip for default (100ms)] -- [/path/to/target] [target_args]

• Note: only non-position-independent target binaries are supported. Be sure to compile all target binaries with the -no-pie compiler flag (unnecessary for Clang).

We extend the afl-cc assembly-time instrumentation with a forkserver-only instrumentation mode for use in benchmarking experiments. To invoke this mode, simply append -Wa,-F to your afl-cc (e.g., afl-gcc, afl-clang) compiler flags and compile as usual. Example:

./configure --disable-shared CC=afl-clang CXX=afl-clang++ CFLAGS="-g -O2 -no-pie -Wa,F" CXXFLAGS="-g -O2 -no-pie -Wa,-F"
make all