New OS Primitives Specialized for Fuzzing

Paper

• Designing New Operating Primitives to Improve Fuzzing Performance (ACM CCS 2017)

The snapshot() system call

• The prototype is built on linux-4.8.10.
• Enable CONFIG_SNAPSHOT when compiling the kernel and check snapshot-test/ for its example.

AFL

• afl/ contains the modified afl source code which leverages the snapshot() system call and the in-memory test case log.
• To enable snapshot(), make sure #define MYFORK in config.h and compile with AFL_PERF=1 make.
• We add a new option -u to indicate the afl instance id and the total number of afl instances running in parallel.
• Currently only 64bit fuzzing targets are supported.

Example

• We provide an example of using modified AFL to fuzz libjpeg (afl-test/).
• Compile libjpeg.

cd jpeg-9b
CC=../../afl/afl-gcc ./configure
make
./djpeg -h (This step cannot be skipped in order to get lt-djpeg)

• Launch afl (here 2 instances)

sudo ./prepare.sh
../afl/afl-fuzz -i input -o output -S slave0 -u 0/2 jpeg-9b/.libs/lt-djpeg

In another terminal,

../afl/afl-fuzz -i input -o output -S slave1 -u 1/2 jpeg-9b/.libs/lt-djpeg

Note that both of the AFL instances will start fuzzing only when both of them have been launched.

Contributors

• Wen Xu (wen.xu@gatech.edu)
• Sanidhya Kashyap (sanidhya@gatech.edu)
• Changwoo Min (changwoo@vt.edu)
• Taesoo Kim (taesoo@gatech.edu)