From d801cb0223da621d7abb7af8b96a848d8976cc9f Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Sun, 23 Feb 2020 21:45:45 +0100 Subject: Update setup_ubuntu-host_qemu-vm_x86-64-kernel.md --- .../setup_ubuntu-host_qemu-vm_x86-64-kernel.md | 43 ++++++++++++++-------- 1 file changed, 28 insertions(+), 15 deletions(-) (limited to 'docs/linux') diff --git a/docs/linux/setup_ubuntu-host_qemu-vm_x86-64-kernel.md b/docs/linux/setup_ubuntu-host_qemu-vm_x86-64-kernel.md index 4b2cb8b5e..8fb299d9d 100644 --- a/docs/linux/setup_ubuntu-host_qemu-vm_x86-64-kernel.md +++ b/docs/linux/setup_ubuntu-host_qemu-vm_x86-64-kernel.md @@ -1,12 +1,11 @@ # Setup: Ubuntu host, QEMU vm, x86-64 kernel -These are the instructions on how to fuzz the x86-64 kernel in a QEMU with Ubuntu 14.04 on the host machine and Debian Stretch in the QEMU instances. +These are the instructions on how to fuzz the x86-64 kernel in a QEMU with Ubuntu on the host machine and Debian Stretch in the QEMU instances. ## GCC -Use the latest compiler from your distro or get the one from [this](/docs/syzbot.md#crash-does-not-reproduce) list and unpack into `$GCC`. +While you may use GCC that is available from your distro, it's preferable to get the lastest one from [this](/docs/syzbot.md#crash-does-not-reproduce) list. Download and unpack into `$GCC`, and you should have GCC binaries in `$GCC/bin/` -Now you should have GCC binaries in `$GCC/bin/`: ``` bash $ ls $GCC/bin/ cpp gcc-ranlib x86_64-pc-linux-gnu-gcc x86_64-pc-linux-gnu-gcc-ranlib @@ -18,11 +17,13 @@ gcc-nm gcov-tool x86_64-pc-linux-gnu-gcc-nm ## Kernel Checkout Linux kernel source: + ``` bash git clone https://github.com/torvalds/linux.git $KERNEL ``` Generate default configs: + ``` bash cd $KERNEL make CC="$GCC/bin/gcc" defconfig @@ -31,6 +32,7 @@ make CC="$GCC/bin/gcc" kvmconfig Now we need to enable some config options required for syzkaller. Edit `.config` file manually and enable: + ``` CONFIG_KCOV=y CONFIG_DEBUG_INFO=y @@ -39,6 +41,7 @@ CONFIG_KASAN_INLINE=y ``` You may also need the following for a recent linux image: + ``` CONFIG_CONFIGFS_FS=y CONFIG_SECURITYFS=y @@ -46,17 +49,20 @@ CONFIG_SECURITYFS=y You might also want to enable some other kernel configs as described [here](kernel_configs.md). -Since enabling these options results in more sub options being available, we need to regenerate config. Run this and press enter each time when prompted for some config value to leave it as default: +Since enabling these options results in more sub options being available, we need to regenerate config: + ``` bash -make CC="$GCC/bin/gcc" oldconfig +make CC="$GCC/bin/gcc" olddefconfig ``` -Build the kernel with previously built GCC: +Build the kernel: + ``` make CC="$GCC/bin/gcc" -j64 ``` Now you should have `vmlinux` (kernel binary) and `bzImage` (packed kernel image): + ``` bash $ ls $KERNEL/vmlinux $KERNEL/vmlinux @@ -67,11 +73,13 @@ $KERNEL/arch/x86/boot/bzImage ## Image Install debootstrap: + ``` bash sudo apt-get install debootstrap ``` -Create a Debian-stretch Linux image: +To create a Debian Stretch Linux image with the minimal set of required packages do: + ``` cd $IMAGE/ wget https://raw.githubusercontent.com/google/syzkaller/master/tools/create-image.sh -O create-image.sh @@ -79,41 +87,42 @@ chmod +x create-image.sh ./create-image.sh ``` -By default, this script will create a minimal Debian-stretch Linux image. The result should be `$IMAGE/stretch.img` disk image. +The result should be `$IMAGE/stretch.img` disk image. + +If you would like to generate an image with Debian Wheezy, instead of Stretch, do: -If you would like to generate wheezy debian image, instead of stretch, just add one option of the script ``` bash ./create-image.sh --distribution wheezy ``` -Sometimes it's useful to have some additional packages and tools available in the VM even though they are not required to run syzkaller. -The instructions to install some useful tools are below. +Sometimes it's useful to have some additional packages and tools available in the VM even though they are not required to run syzkaller. To install a set of tools we find useful do (feel free to edit the list of tools in the script): -To install other packages, like `make sysbench git vim tmux usbutils` (not required to run syzkaller): ``` bash ./create-image.sh --feature full ``` -To install perf (not required to run syzkaller): +To install perf (not required to run syzkaller; requires `$KERNEL` to point to the kernel sources): + ``` bash ./create-image.sh --add-perf ``` -Note: remember to set `$KERNEL` before installing perf For additional options of `create-image.sh`, please refer to `./create-image.sh -h` ## QEMU Install `QEMU`: + ``` bash sudo apt-get install qemu-system-x86 ``` Make sure the kernel boots and `sshd` starts: + ``` bash qemu-system-x86_64 \ -kernel $KERNEL/arch/x86/boot/bzImage \ - -append "console=ttyS0 root=/dev/sda debug earlyprintk=serial slub_debug=QUZ"\ + -append "console=ttyS0 root=/dev/sda earlyprintk=serial"\ -hda $IMAGE/stretch.img \ -net user,hostfwd=tcp::10021-:22 -net nic \ -enable-kvm \ @@ -144,6 +153,7 @@ Booting the kernel. ``` After that you should be able to ssh to QEMU instance in another terminal: + ``` bash ssh -i $IMAGE/stretch.id_rsa -p 10021 -o "StrictHostKeyChecking no" root@localhost ``` @@ -152,6 +162,7 @@ If this fails with "too many tries", ssh may be passing default keys before the one explicitly passed with `-i`. Append option `-o "IdentitiesOnly yes"`. To kill the running QEMU instance: + ``` bash kill $(cat vm.pid) ``` @@ -161,6 +172,7 @@ kill $(cat vm.pid) Build syzkaller as described [here](/docs/contributing.md). Then create a manager config like the following, replacing the environment variables `$GOPATH`, `$KERNEL` and `$IMAGE` with their actual values. + ``` { "target": "linux/amd64", @@ -182,6 +194,7 @@ variables `$GOPATH`, `$KERNEL` and `$IMAGE` with their actual values. ``` Run syzkaller manager: + ``` bash mkdir workdir ./bin/syz-manager -config=my.cfg -- cgit mrf-deployment