# sshpiper 🖇
[](https://github.com/tg123/sshpiper/actions/workflows/e2e.yml)
[](https://goreportcard.com/report/github.com/tg123/sshpiper)
[](https://hub.docker.com/r/farmer1992/sshpiperd)
`sshpiper` is the reverse proxy for sshd. all protocols, including ssh, scp, port forwarding, running on top of ssh are supported.
*Note:* this is `v1` version, checkout legacy `v0` [here](https://github.com/tg123/sshpiper/tree/v0)
### Overview and Terminology
* `downstream`: the client side, typically an ssh client.
* `upstream`: the server side, typically an ssh server.
* `plugin`: handles the routing from `downstream` to `upstream`. The `plugin` is also responsible for mapping authentication methods to the upstream server. For example, the downstream may use password authentication, but the upstream server may receive public key authentication mapped by `sshpiper`.
* `additional challenge`: some `plugins` will not only perform routing but also add additional challenges to SSH authentication for the `upstream` server. For example, the `downstream` may be asked for two-factor authentication provided by the `plugin`.
```
+---------+ +------------------+ +-----------------+
| | | | | |
| Bob +----ssh -l bob----+ | sshpiper +-------------> Bob' machine |
| | | | | | | |
+---------+ | | | | +-----------------+
+---> pipe-by-name--+ |
+---------+ | | | | +-----------------+
| | | | | | | |
| Alice +----ssh -l alice--+ | +-------------> Alice' machine |
| | | | | |
+---------+ +------------------+ +-----------------+
downstream sshpiper upstream
```
## Quick start
### Build
```
git clone https://github.com/tg123/sshpiper
cd sshpiper
git submodule update --init --recursive
mkdir out
go build -tags full -o out ./...
```
## Run simple demo
### start dummy sshd server
```
docker run -d -e USER_NAME=user -e USER_PASSWORD=pass -e PASSWORD_ACCESS=true -p 127.0.0.1:5522:2222 lscr.io/linuxserver/openssh-server
```
### start `sshpiperd` with `fixed` plugin targeting the dummy sshd server
```
./out/sshpiperd -i /tmp/sshpiperkey --server-key-generate-mode notexist --log-level=trace ./out/fixed --target 127.0.0.1:5522
```
### test ssh connection (password: `pass`)
```
ssh 127.0.0.1 -l user -p 2222
```
### âž• math before login?
Here illustrates the example of `addional challenge` before the `fixed` plugin.
```
./out/sshpiperd -i /tmp/sshpiperkey --server-key-generate-mode notexist --log-level=trace ./out/simplemath -- ./out/fixed --target 127.0.0.1:5522
```
## Plugins
### icons
* 🔀: routing plugin
* 🔒: addtional challenge plugin
Plugin list
* [workingdir](plugin/workingdir/) 🔀: `/home`-like directory to managed upstreams routing by sshpiped.
* [yaml](plugin/yaml/) 🔀: config routing with a single yaml file.
* [docker](plugin/docker/) 🔀: pipe into docker containers.
* [kubernetes](plugin/kubernetes/) 🔀: manage pipes via Kubernetes CRD.
* [totp](plugin/totp/) 🔒: TOTP 2FA plugin. compatible with all [RFC6238](https://datatracker.ietf.org/doc/html/rfc6238) authenticator, for example: `google authenticator`, `azure authenticator`.
* [azdevicecode](https://github.com/tg123/sshpiper-plugins/tree/main/azdevicecode) 🔒: ask user to enter [azure device code](https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-device-code) before login
* [fixed](plugin/fixed/) 🔀: fixed targeting the dummy sshd server
* [simplemath](plugin/simplemath/) 🔒: ask for very simple math question before login, demo purpose
* [githubapp](https://github.com/tg123/sshpiper-gh) 🔀: login ssh with your github account
* [restful](https://github.com/11notes/docker-sshpiper) by [@11notes](https://github.com/11notes) 🔀🔒: The rest plugin for sshpiperd is a simple plugin that allows you to use a restful backend for authentication and challenge.
* [failtoban](plugin/failtoban/) 🔒: ban ip after failed login attempts
* [openpubkey](https://github.com/tg123/sshpiper-openpubkey)🔀🔒: integrate with [openpubkey](https://github.com/openpubkey/openpubkey)
## Screening recording
### asciicast
recording the screen in `asciicast` format
To use it, start sshpiperd with `--screen-recording-format asciicast` and `--screen-recording-dir /path/to/recordingdir`
Example:
```
ssh user_name@
... do some commands
exit
asciinema play /path/to/recordingdir//shell-channel-0.cast
```
### typescript
recording the screen in `typescript` format (not the lang). The format is compatible with [scriptreplay(1)](https://linux.die.net/man/1/scriptreplay)
To use it, start sshpiperd with `--screen-recording-format typescript` and `--screen-recording-dir /path/to/recordingdir`
Example:
```
ssh user_name@127.0.0.1 -p 2222
... do some commands
exit
$ cd /path/to/recordingdir/
$ ls *.timing *.typescript
1472847798.timing 1472847798.typescript
$ scriptreplay -t 1472847798.timing 1472847798.typescript # will replay the ssh session
```
## Public key authentication when using sshpiper (Private key remapping)
During SSH publickey auth, [RFC 4252 Section 7](http://tools.ietf.org/html/rfc4252#section-7),
ssh client sign `session_id` and some other data using private key into a signature `sig`.
This is for server to verify that the connection is from the client not `the man in the middle`.
However, sshpiper actually holds two ssh connection, and it is doing what `the man in the middle` does.
the two ssh connections' `session_id` will never be the same, because they are hash of the shared secret. [RFC 4253 Section 7.2](http://tools.ietf.org/html/rfc4253#section-7).
To support publickey auth, `sshpiper` routing plugin must provide a new private key for the `upstream` to sign the `session_id`. This new private key is called `mapping key`.
How this work
```
+------------+ +------------------------+
| | | |
| client | | sshpiper |
| PK_X +--------> | |
| | | v |
| | | Check Permission |
+------------+ | | |
| | |
| | | +----------------+
| v | | |
| sign again | | server |
| using PK_Y +--------------> check PK_Y |
| | | |
| | | |
+------------------------+ +----------------+
```
## Ports to other platforms
* [sshpiper on OpenWrt](https://github.com/ihidchaos/sshpiper-openwrt) by [@ihidchaos](https://github.com/ihidchaos)
## Migrating from `v0`
### What's the major change in `v1`
* low level sshpiper api is fully redesigned to support more routing protocols.
* plugins system totally redesigned to be more flexible and extensible.
* plugins are now sperated from main process and no longer a single big binary, this allow user to write their own plugins without touching `sshpiperd` code.
* `grpc` is first class now, the plugins are built on top of it
For plugins already in `v1`, you need change params to new params. However, not all plugins are migrated to `v1` yet, they are being migrated gradually. you can still use the old plugins in [`v0` branch](https://github.com/tg123/sshpiper/tree/v0)
## Contributing
see [CONTRIBUTING.md](CONTRIBUTING.md)
## License
MIT