Instructions to set up syzkaller for a Linux Host and an amd64 NetBSD kernel.
Get the NetBSD kernel source (preferably HEAD).
$ mdkir $HOME/netbsd $ cd $HOME/netbsd $ git clone https://github.com/NetBSD/src.git
Build the tools (You will have the toolchain in $HOME/netbsd/tools)
$ cd src $ ./build.sh -m amd64 -U -T ../tools tools
Build the Distribution (This might take a while)
$ ./build.sh -m amd64 -U -T ../tools -D ../dest distribution
At this point you should have a NetBSD distribution at $HOME/netbsd/dest.
Install all the dependencies for Syzkaller (Go distribution can be downloaded from https://golang.org/dl/)
Clone the Syzkaller Repository
$ go get -u -d github.com/google/syzkaller/.. $ cd ~/go/src/github.com/google/syzkaller
Compile Syzkaller for NetBSD
$ make TARGETOS=netbsd SOURCEDIR=$HOME/netbsd/src
The above steps should have built the Syzkaller binaries for NetBSD.
You can see the compiled binaries in bin/netbsd_amd64.
You can use the script given here to create a disk image with NetBSD installed. The script would also automatically give you a ssh key to ssh into the VM.
Alternatively, You can follow the tutorial given here to setup a basic NetBSD VM with qemu.
After installing and running the NetBSD VM on qemu please follow the steps below to configure ssh.
Create a ssh-keypair on the host and save it as netbsdkey.
$ ssh-keygen -f netbsdkey -t rsa -N ""
Append the following lines to /etc/rc.conf on the guest. (use vi editor)
sshd=YES dhcpcd=YES ifconfig_wm0="inet 10.0.2.15 netmask 255.255.255.0"
Append this to /etc/ssh/sshd_config on the guest.
Port 22 ListenAddress 10.0.2.15 PermitRootLogin yes PermitRootLogin without-password
Now you should be able to ssh into the netbsd VM.
$ ssh -p 10022 root@127.0.0.1
Copy and paste your public key to /root/.ssh/authorized_keys on the guest and reboot the VM.
After reboot make sure that the ssh is working properly. Replace the port with what you have configured.
$ ssh -i path/to/netbsdkey -p 10022 root@127.0.0.1
If the last command returns a proper shell it means the VM has been configured.
You can compile a kernel with KASAN to increase the chances of finding bugs.
Make a copy of the config file
$ cd $HOME/netbsd/src $ cp sys/arch/amd64/conf/GENERIC sys/arch/amd64/conf/SYZKALLER
Uncomment the following lines in sys/arch/amd64/conf/SYZKALLER to enable KASAN
#makeoptions KASAN=1 # Kernel Address Sanitizer #options KASAN #no options SVS
Compile the kernel with KASAN (Assuming you have followed the inital steps to build tools)
$ cd $HOME/netbsd/src $ ./build.sh -m amd64 -U -T ../tools -j4 kernel=SYZKALLER
At this point you should have the new compiled kernel image which can be found in $HOME/netbsd/src/sys/arch/amd64/compile/SYZKALLER and should have the name netbsd. You need to copy it to the installed VM and reboot the VM.
poweroff the VM and create netbsd.cfg config file with the following contents (alter paths as necessary): {
"name": "netbsd",
"target": "netbsd/amd64",
"http": ":10000",
"workdir": "work",
"syzkaller": "$GOPATH/src/github.com/google/syzkaller",
"image": "path/to/netbsd.img",
"sshkey": "/path/to/netbsdkey",
"sandbox": "none",
"procs": 2,
"cover": false,
"type": "qemu",
"vm": {
"qemu": "qemu-system-x86_64",
"count": 2,
"cpu": 2,
"mem": 2048
}
}
(Above directories have to be specified to the exact locations and the ssh keys must be in a separate directory with chmod 700 permissions set to that directory and chmod 600 permissions to the files in both the guest and the host.)
syz-manager with: (Inside the syzkaller folder where the netbsd.cfg file also exists)$ bin/syz-manager -config netbsd.cfg
(You can add a -debug flag to the above command to view the log if any issues arise.)
booting test machines... wait for the connection from test machine... machine check: 253 calls enabled, kcov=true, kleakcheck=false, faultinjection=false, comps=false executed 3622, cover 1219, crashes 0, repro 0 executed 7921, cover 1239, crashes 0, repro 0 executed 32807, cover 1244, crashes 0, repro 0 executed 35803, cover 1248, crashes 0, repro 0
syzbot tests NetBSD and reports bugs to syzkaller-netbsd-bugs mailing list (also can be seen on dashboard).
The image syzbot uses can be downloaded from here (2GB) and root ssh key from here.
The image can be used with qemu as follows:
qemu-system-x86_64 -m 1024 -smp 2 -nographic -enable-kvm \ -netdev user,id=mynet0,hostfwd=tcp:127.0.0.1:10022-:22 \ -device e1000,netdev=mynet0 -hda netbsd-image.raw
And then you can ssh/scp into the VM using:
ssh -i netbsd-image.key -p 10022 -o IdentitiesOnly=yes root@localhost scp -i netbsd-image.key -P 10022 -o IdentitiesOnly=yes FILE root@localhost:/root/
Note: the image contains a stock kernel, so if you are reproducing a bug most likely you want to update kernel as the first step:
scp -i netbsd-image.key -P 10022 -o IdentitiesOnly=yes \ src/sys/arch/amd64/compile/obj/GENERIC_SYZKALLER/netbsd root@localhost:/netbsd ssh -i netbsd-image.key -p 10022 -o IdentitiesOnly=yes root@localhost /sbin/reboot
anita using just a single command.sys/netbsd/*.txt is a dirty copy from sys/linux/*.txt with everything that does not compile dropped. We need to go through syscalls and verify/fix/extend them, including devices/ioctls/etc.amd64 arch is supported. Supporting 386 would be useful, because it should cover compat paths. Also, we could do testing of the linux-compatibility subsystem.pkg/host needs to be taught how to detect supported syscalls/devices.