Case Study -- Binutils

The GNU Binutils are a collection of binary tools widely used in GNU/Linux. We use this to demonstrate how to use Hakweye to fuzz with binaries with a given build script. In this case, we deal with the CVE-2016-4487 case, where the target site is according to the bug report page.

Get Binutils-2.26 source code

mkdir 4487

export INFO_DIR=$PWD/4487

wget https://ftp.gnu.org/gnu/binutils/binutils-2.26.tar.gz && tar xf binutils-2.26.tar.gz

export SRC_DIR=$PWD/binutils-2.26

Prepare "llvm.toml" and "tgt_lines.in" in $INFO_DIR:

# llvm.toml

[tgt]

infile = "tgt_lines.in"

out_dir = "."

[ins]

proj_name = "binutils-4487"

dist_file = "bb.dist"

# tgt_lines.in

/home/fot/test-ccs/binutils-2.26/libiberty/cplus-dem.c:4300

Preprocessing with fot-pp

cd $SRC_DIR

export CFLAGS="-Wno-error -g $HE_FLAGS"

export CXXFLAGS="-Wno-error -g $HE_FLAGS"

export LDFLAGS="-ldl"

../configure --disable-shared --disable-werror --prefix=$PWD/install

make -j

There will be an LLVM Bitcode file "cxxfilt.0.0.preopt.bc".

Analyze the bitcode with "libfot-tgt.so"

cp cxxfilt.0.0.preopt.bc $INFO_DIR

cd $INFO_DIR

opt-6.0 -mem2reg -load /usr/local/lib/fot/libfot-tgt.so -fot-conf ./llvm.toml -fot-analyze ./cxxfilt.0.0.preopt.bc -o /dev/null

Generate distances:

fot-dists -b ./cxxfilt.0.0.preopt.bc -i $PWD

Compile and Instrument

export HE_FLAGS="-fot-conf=$INFO_DIR/llvm.toml"

cd $SRC_DIR

make clean

export CFLAGS="-Wno-error -g $HE_FLAGS"

export CXXFLAGS="-Wno-error -g $HE_FLAGS"

export LDFLAGS="-ldl"

../configure --disable-shared --disable-werror --prefix=$PWD/install

make

Map function traces:

cd $INFO_DIR

fot-funcs extract -p binutils-4487

fot-funcs score -d funcs.dist -m funcs.txt -p proj_trace_funcs.json -o trace_funcs.json

Specify configuration for fuzzing:

[io]

in_folder = "in"

out_folder = "out"

[exec]

use_forkserver = true

mem_limit = 200

timeout = 50

qemu_mode = false

[exec.sa]

trace_func_file = "trace_funcs.json"

callgraph_file = "callgraph.yaml"

tgt_func_file = "tgt_funcs.txt"

[record]

proj_name = "binutils-4487"

interval = 2000

url = "redis://127.0.0.1/"

log_entry_info = false

[calibration]

# for simple regular case calibration

normal_cycles = 7

# for variable behaviors calibration

var_behavior_cycles = 37

[minimize]

ck_redundant_file = false

[mutation]

# ops = ["det", "dict", "havoc", "splice"]

# ops = ["havoc", "splice", "sem"]

max_file_length = 128

#dict_folder = "dicts_test"

dict_level = 0

# max_token_length: 64

# min_token_length: 2

# max_dict_size: 256

# in minutes

havoc_adjust_duration = 12

[fz]

workers = 1

bind_cpu = false

# "normal"/"crash"

keep_mode = "normal"

# "simple"/...

scorer = "simple"

exit_nonzero_as_crash = false

ignored_signals = []

[fz.conductor]

# in minutes

report_duration = 3

[fz.sync]

duration = 200

execs = 5

Run the fuzzer:

mkdir in

echo "" > in/file

fot-fuzz -c ./Config.toml -- $SRC_DIR/binutils/cxxfilt

# cxxfilt accepts input from stdin

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