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diff --git a/docs/setup.md b/docs/setup.md index 7205b356d..cadc4ca26 100644 --- a/docs/setup.md +++ b/docs/setup.md @@ -1,116 +1,28 @@ -# Setup - -## Install - -The following components are needed to use syzkaller: - - - C compiler with coverage support - - Linux kernel with coverage additions - - Virtual machine or a physical device - - syzkaller itself - -Generic steps to set up syzkaller are described below. -More specific information (like the exact steps for a particular host system, VM type and a kernel architecture) can be found on the following pages: - -- [Setup: Ubuntu host, QEMU vm, x86-64 kernel](docs/setup_ubuntu-host_qemu-vm_x86-64-kernel.md) -- [Setup: Ubuntu host, Odroid C2 board, arm64 kernel](docs/setup_ubuntu-host_odroid-c2-board_arm64-kernel.md) -- [Setup: Linux host, QEMU vm, arm64 kernel](docs/setup_linux-host_qemu-vm_arm64-kernel.md) -- [Setup: Linux host, Android device, arm64 kernel](docs/setup_linux-host_android-device_arm64-kernel.md) - -If you encounter any troubles, check the [troubleshooting](troubleshooting.md) page. - -### C Compiler - -Syzkaller is a coverage-guided fuzzer and therefore it needs the kernel to be built with coverage support, which requires a recent GCC version. -Coverage support was submitted to GCC in revision `231296`, released in GCC v6.0. - -### Linux Kernel - -Besides coverage support in GCC, you also need support for it on the kernel side. -KCOV was committed upstream in Linux kernel version 4.6 and can be enabled by configuring the kernel with `CONFIG_KCOV=y`. -For older kernels you need to backport commit [kernel: add kcov code coverage](https://github.com/torvalds/linux/commit/5c9a8750a6409c63a0f01d51a9024861022f6593). - -To enable more syzkaller features and improve bug detection abilities, it's recommended to use additional config options. -See [this page](linux_kernel_configs.md) for details. - -### VM Setup - -Syzkaller performs kernel fuzzing on slave virtual machines or physical devices. -These slave enviroments are referred to as VMs. -Out-of-the-box syzkaller supports QEMU, kvmtool and GCE virtual machines, Android devices and Odroid C2 boards. - -These are the generic requirements for a syzkaller VM: - - - The fuzzing processes communicate with the outside world, so the VM image needs to include - networking support. - - The program files for the fuzzer processes are transmitted into the VM using SSH, so the VM image - needs a running SSH server. - - The VM's SSH configuration should be set up to allow root access for the identity that is - included in the `syz-manager`'s configuration. In other words, you should be able to do `ssh -i - $SSHID -p $PORT root@localhost` without being prompted for a password (where `SSHID` is the SSH - identification file and `PORT` is the port that are specified in the `syz-manager` configuration - file). - - The kernel exports coverage information via a debugfs entry, so the VM image needs to mount - the debugfs filesystem at `/sys/kernel/debug`. - -To use QEMU syzkaller VMs you have to install QEMU on your host system, see [QEMU docs](http://wiki.qemu.org/Manual) for details. -The [create-image.sh](tools/create-image.sh) script can be used to create a suitable Linux image. -Detailed steps for setting up syzkaller with QEMU on a Linux host are avaialble for [x86-64](setup_ubuntu-host_qemu-vm_x86-64-kernel.md) and [arm64](setup_linux-host_qemu-vm_arm64-kernel.md) kernels. - -For some details on fuzzing the kernel on an Android device check out [this page](setup_linux-host_android-device_arm64-kernel.md) and the explicit instructions for an Odroid C2 board are available [here](setup_ubuntu-host_odroid-c2-board_arm64-kernel.md). - -### Syzkaller - -The syzkaller tools are written in [Go](https://golang.org), so a Go compiler (>= 1.8) is needed -to build them. - -Go distribution can be downloaded from https://golang.org/dl/. -Unpack Go into a directory, say, `$HOME/go`. -Then, set `GOROOT=$HOME/go` env var. -Then, add Go binaries to `PATH`, `PATH=$HOME/go/bin:$PATH`. -Then, set `GOPATH` env var to some empty dir, say `GOPATH=$HOME/gopath`. -Then, run `go get -u -d github.com/google/syzkaller/...` to checkout syzkaller sources with all dependencies. -Then, `cd $GOPATH/src/github.com/google/syzkaller` and -build with `make`, which generates compiled binaries in the `bin/` folder. - -To build additional syzkaller tools run `make all-tools`. - -## Configuration - -The operation of the syzkaller `syz-manager` process is governed by a configuration file, passed at -invocation time with the `-config` option. This configuration can be based on the -[example](syz-manager/config/testdata/qemu.cfg); the file is in JSON format with the -following keys in its top-level object: - - - `http`: URL that will display information about the running `syz-manager` process. - - `workdir`: Location of a working directory for the `syz-manager` process. Outputs here include: - - `<workdir>/crashes/*`: crash output files (see [Crash Reports](#crash-reports)) - - `<workdir>/corpus.db`: corpus with interesting programs - - `<workdir>/instance-x`: per VM instance temporary files - - `syzkaller`: Location of the `syzkaller` checkout. - - `vmlinux`: Location of the `vmlinux` file that corresponds to the kernel being tested. - - `procs`: Number of parallel test processes in each VM (4 or 8 would be a reasonable number). - - `leak`: Detect memory leaks with kmemleak. - - `image`: Location of the disk image file for the QEMU instance; a copy of this file is passed as the - `-hda` option to `qemu-system-x86_64`. - - `sandbox` : Sandboxing mode, the following modes are supported: - - "none": don't do anything special (has false positives, e.g. due to killing init) - - "setuid": impersonate into user nobody (65534), default - - "namespace": use namespaces to drop privileges - (requires a kernel built with `CONFIG_NAMESPACES`, `CONFIG_UTS_NS`, - `CONFIG_USER_NS`, `CONFIG_PID_NS` and `CONFIG_NET_NS`) - - `enable_syscalls`: List of syscalls to test (optional). - - `disable_syscalls`: List of system calls that should be treated as disabled (optional). - - `suppressions`: List of regexps for known bugs. - - `type`: Type of virtual machine to use, e.g. `qemu` or `adb`. - - `vm`: object with VM-type-specific parameters; for example, for `qemu` type paramters include: - - `count`: Number of VMs to run in parallel. - - `kernel`: Location of the `bzImage` file for the kernel to be tested; - this is passed as the `-kernel` option to `qemu-system-x86_64`. - - `cmdline`: Additional command line options for the booting kernel, for example `root=/dev/sda1`. - - `sshkey`: Location (on the host machine) of an SSH identity to use for communicating with - the virtual machine. - - `cpu`: Number of CPUs to simulate in the VM (*not currently used*). - - `mem`: Amount of memory (in MiB) for the VM; this is passed as the `-m` option to `qemu-system-x86_64`. - -See also [config.go](syz-manager/config/config.go) for all config parameters. +# How to install syzkaller + +Generic setup instructions are outlined [here](setup_generic.md). +Instructions for a particular VM or kernel arch can be found on these pages: + +- [Setup: Ubuntu host, QEMU vm, x86-64 kernel](setup_ubuntu-host_qemu-vm_x86-64-kernel.md) +- [Setup: Ubuntu host, Odroid C2 board, arm64 kernel](setup_ubuntu-host_odroid-c2-board_arm64-kernel.md) +- [Setup: Linux host, QEMU vm, arm64 kernel](setup_linux-host_qemu-vm_arm64-kernel.md) +- [Setup: Linux host, Android device, arm64 kernel](setup_linux-host_android-device_arm64-kernel.md) + +After following these instructions you should be able to run `syz-manager`, see it executing programs and be able to access statistics exposed at `http://127.0.0.1:56741`: + +``` +$ ./bin/syz-manager -config=my.cfg +2017/06/14 16:39:05 loading corpus... +2017/06/14 16:39:05 loaded 0 programs (0 total, 0 deleted) +2017/06/14 16:39:05 serving http on http://127.0.0.1:56741 +2017/06/14 16:39:05 serving rpc on tcp://127.0.0.1:34918 +2017/06/14 16:39:05 booting test machines... +2017/06/14 16:39:05 wait for the connection from test machine... +2017/06/14 16:39:59 received first connection from test machine vm-9 +2017/06/14 16:40:05 executed programs: 9, crashes: 0 +2017/06/14 16:40:15 executed programs: 13, crashes: 0 +2017/06/14 16:40:25 executed programs: 15042, crashes: 0 +2017/06/14 16:40:35 executed programs: 24391, crashes: 0 +``` + +More information on the configuration file format is available [here](configuration.md). |