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out-of-tree/docs/introduction.rst
2019-08-21 06:16:25 +00:00

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Introduction
============
*out-of-tree* is written in *Go*, it uses *Docker* for generating
kernel/filesystem images and *Qemu* for virtualization.
Also it possible to generate kernels from the host system and use the
custom one.
*out-of-tree* supports *GNU/Linux* (usually it's tested on NixOS and
latest Ubuntu LTS) and *macOS*. Technically all systems that supported
by Go, Docker, and Qemu must work well. Create the issue if you'll
notice any issue in integration for your operating system.
All *Qemu* interaction is stateless.
*out-of-tree* is allow and require metadata (``.out-of-tree.toml``)
for work. TOML (Tom's Obvious, Minimal Language) is used for kernel
module/exploit description.
``.out-of-tree.toml`` is mandatory, you need to have in the current
directory (usually, it's a project of kernel module/exploit) or use
the ``--path`` flag.
Files
-----
All data is stored in ``~/.out-of-tree/``.
- *db.sqlite* contains logs related to run with ``out-of-tree pew``,
debug mode (``out-of-tree debug``) is not store any data.
- *images* used for filesystem images (rootfs images that used for
``qemu -hda ...``) that can be generated with the
``tools/qemu-*-img/...``.
- *kernels* stores all kernel ``vmlinuz/initrd/config/...`` files that
generated previously with a some *Docker magic*.
- *kernels.toml* contains metadata for generated kernels. It's not
supposed to be edited by hands.
- *kernels.user.toml* is default path for custom kernels definition.
- *Ubuntu* (or *Centos*/*Debian*/...) is the Dockerfiles tree
(DistroName/DistroVersion/Dockerfile). Each Dockerfile contains a
base layer and incrementally updated list of kernels that must be
installed.
Overview
---------
*out-of-tree* creating debugging environment based on **defined** kernels::
$ out-of-tree debug --kernel 'Ubuntu:4.15.0-58-generic'
[*] KASLR SMEP SMAP
[*] gdb is listening on tcp::1234
[*] build result copied to /tmp/exploit
ssh -o StrictHostKeyChecking=no -p 29308 root@127.133.45.236
gdb /usr/lib/debug/boot/vmlinux-4.15.0-58-generic -ex 'target remote tcp::1234'
out-of-tree> help
help : print this help message
log : print qemu log
clog : print qemu log and cleanup buffer
cleanup : cleanup qemu log buffer
ssh : print arguments to ssh command
quit : quit
out-of-tree>
*out-of-tree* uses three stages for automated runs:
- Build
- Inside the docker container (default).
- Binary version (de facto skip stage).
- On host.
- Run
- Insmod for the kernel module.
- This step is skipped for exploits.
- Test
- Run the test.sh script on the target machine.
- Test script is run from *root* for the kernel module.
- Test script is run from *user* for the kernel exploit.
- Test script for the kernel module is fully custom (only return
value is checked).
- Test script for the kernel exploit receives two parameters:
- Path to exploit
- Path to file that must be created with root privileges.
- If there's no test.sh script then default
(``echo touch FILE | exploit``) one is used.
Security
--------
*out-of-tree* is not supposed to be used on multi-user systems or with
an untrusted input.
Meanwhile, all modern hypervisors are supporting nested
virtualization, which means you can use it for isolating *out-of-tree*
if you want to work with an untrusted input (e.g. with a mass-scale
testing public proofs-of-concept).