README.md

starnix support

Prerequisites

To run syzkaller for fuzzing starnix, you will need a checkout of the Fuchsia source repository.

The rest of this document will use the environment variable SOURCEDIR to identify the path to your Fuchsia checkout (e.g. /home/you/fuchsia). The commands below assume you have set SOURCEDIR, like so:

export SOURCEDIR=/home/you/fuchsia

To build Fuchsia for qemu-x64, run:

fx --dir "out/qemu-x64" set workstation_eng.qemu-x64 \
  --with "//bundles/tools" \
  --with "//src/proc/bin/starnix"
fx build

You will also need to follow the instructions in the sections GCC and Kernel of the setup_ubuntu-host_qemu-vm_x86-64-kernel.md file.

syzkaller

Building binaries for starnix

First, you need to build all the binaries required for running syzkaller in starnix. For that, you only need to run this from inside your syzkaller checkout (assuming you built Fuchsia for x64):

SYZ_STARNIX_HACK=1 make TARGETOS=linux TARGETARCH=amd64

Configuration file

Create a manager config like the following, replacing the environment variables $SYZKALLER, $KERNEL and $IMAGE with their actual values.

NOTE: ffx is still under development, for that reason VM count of 1 is recommended until fxbug.dev/118926 is solved.

{
    "target": "linux/amd64",
    "http": "127.0.0.1:56741",
    "workdir": "$SYZKALLER/workdir",
    "kernel_obj": "$KERNEL",
    "kernel_src": "$SOURCEDIR",
    "syzkaller": "$SYZKALLER",
    "procs": 8,
    "type": "starnix",
    "vm": {
        "count": 1
    },
    "cover": false
}

Running

Lastly, just run the command below to start fuzzing.

SYZ_STARNIX_HACK=1 bin/syz-manager -config=./starnix.cfg