158 lines
No EOL
6.7 KiB
Markdown
158 lines
No EOL
6.7 KiB
Markdown
# sshpiper 🖇
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[](https://goreportcard.com/report/github.com/tg123/sshpiper)
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[](https://hub.docker.com/r/farmer1992/sshpiperd)
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`sshpiper` is the reverse proxy for sshd. all protocols, including ssh, scp, port forwarding, running on top of ssh are supported.
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*Note:* this is `v1` version, checkout legacy `v0` [here](https://github.com/tg123/sshpiper/tree/v0)
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### Overview and Terminology
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* `downstream`: the client side, typicall ssh client
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* `upstream`: the server side, typicall sshd server
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* `plugin`: handles the routing from `downstream` to `upstream`. the `plugin` are also repsonsible for the mapping authentication methods to upstream. for exmaple, the downstream may use password as authentication method, but the upstream may receive public key authentication mapped by `sshpiper`.
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* `addtional chanllenge`: some `plugin` will not do routing but add an additional challenges to ssh authentication to `upstream`. for example, the `downstream` may be asked for two factor authentication provided by the `plugin`.
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```
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+---------+ +------------------+ +-----------------+
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| Bob +----ssh -l bob----+ | sshpiper +-------------> Bob' machine |
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+---------+ | | | | +-----------------+
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+---> pipe-by-name--+ |
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+---------+ | | | | +-----------------+
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| Alice +----ssh -l alice--+ | +-------------> Alice' machine |
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+---------+ +------------------+ +-----------------+
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downstream sshpiper upstream
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```
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## Quick start
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### Build
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```
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git clone https://github.com/tg123/sshpiper
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cd sshpiper
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git submodule update --init --recursive
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mkdir out
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go build -o out ./...
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```
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## Run simple demo
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### start dummy sshd server
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```
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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
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```
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### start `sshpiperd` with `fixed` plugin targetting the dummy sshd server
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```
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sudo ./out/sshpiperd ./out/fixed --target 127.0.0.1:5522
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```
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### test ssh connection (password: `pass`)
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```
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ssh 127.0.0.1 -l user -p 2222
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```
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### ➕ math before login?
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Here illustrates the example of `addional challenge` before the `fixed` plugin.
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```
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sudo ./out/sshpiperd --log-level=trace ./out/simplemath -- ./out/fixed --target 127.0.0.1:5522
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```
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## Plugins
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### icons
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* 🔀: routing plugin
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* 🔒: addtional challenge plugin
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Plugin list
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* [workingdir](plugin/workingdir/) 🔀: `/home`-like directory to managed upstreams routing by sshpiped.
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* [azdevicecode](plugin/azdevicecode/) 🔒: ask user to enter [azure device code](https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-device-code) before login
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* [fixed](plugin/fixed/) 🔀: fixed targetting the dummy sshd server
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* [simplemath](plugin/simplemath/) 🔒: ask for very simple math question before login, demo purpose
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## Screening recording
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`sshpiperd` support recording the screen in `typescript` format (not the lang). The format is compatible with [scriptreplay(1)](https://linux.die.net/man/1/scriptreplay)
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To use it, start sshpiperd with `--typescript-log-dir loggingdir`
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Example:
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```
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ssh user_name@127.0.0.1 -p 2222
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... do some commands
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exit
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$ cd loggingdir/user_name
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$ ls *.timing *.typescript
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1472847798.timing 1472847798.typescript
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$ scriptreplay -t 1472847798.timing 1472847798.typescript # will replay the ssh session
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```
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## Public key authentication when using sshpiper (Private key remapping)
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During SSH publickey auth, [RFC 4252 Section 7](http://tools.ietf.org/html/rfc4252#section-7),
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ssh client sign `session_id` and some other data using private key into a signature `sig`.
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This is for server to verify that the connection is from the client not `the man in the middle`.
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However, sshpiper actually holds two ssh connection, and it is doing what `the man in the middle` does.
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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).
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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`.
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How this work
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```
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+------------+ +------------------------+
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| client | | sshpiper |
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| PK_X +--------> | |
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| | | v |
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| | | Check Permission |
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+------------+ | | |
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| | | +----------------+
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| v | | |
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| sign agian | | server |
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| using PK_Y +--------------> check PK_Y |
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+------------------------+ +----------------+
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```
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## Migrating from `v0`
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### What's the major change in `v1`
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* low level sshpiper api is fully redesigned to support more routing protocols.
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* plugins system totally redesigned to be more flexible and extensible.
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* 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.
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* `grpc` is first class now, the plugins are built on top of it
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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)
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## License
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MIT |