SSH Piper works as a proxy-like ware, and route connections by username, src ip , etc.
+---------+ +------------------+ +-----------------+
| | | | | |
| Bob +----ssh -l bob----+ | SSH Piper +-------------> Bob' machine |
| | | | | | | |
+---------+ | | | | +-----------------+
+---> pipe-by-name--+ |
+---------+ | | | | +-----------------+
| | | | | | | |
| Alice +----ssh -l alice--+ | +-------------> Alice' machine |
| | | | | |
+---------+ +------------------+ +-----------------+
Downstream SSH Piper Upstream
Demo
git clone
cd sshpiper/sshpiperd/
go build
with pam module support
go build -tags pam
with Docker image
docker run farmer1992/sshpiperd
Run with Workding Dir upstream driver
docker run -d -p 2222:2222 \
-v /etc/ssh/ssh_host_rsa_key:/etc/ssh/ssh_host_rsa_key \
-v /YOUR_WORKING_DIR:/var/sshpiper \
farmer1992/sshpiperd
Run with Additional Challenge
use env SSHPIPERD_CHALLENGER to specify which challenger to use
docker run -d -p 2222:2222 \
-e SSHPIPERD_CHALLENGER=pam \
-v /YOUR_PAM_CONFIG:/etc/pam.d/sshpiperd \
-v /etc/ssh/ssh_host_rsa_key:/etc/ssh/ssh_host_rsa_key \
-v /YOUR_WORKING_DIR:/var/sshpiper \
farmer1992/sshpiperd
with Snap
sudo snap install sshpiperd
configure with snap
sudo snap set sshpiperd 'port=3333'
sudo snap restart sshpiperd
NOTE:
- Default working dir for snap verion is
/var/snap/sshpiperd/common - use classic mode if PAM is not working:
sudo snap install --classic sshpiperd
Just run showme.sh in sshpiperd example directory
or
Copy paste command below to run
go get github.com/tg123/sshpiper/sshpiperd && `go env GOPATH`/src/github.com/tg123/sshpiper/sshpiperd/example/showme.sh
the example script will setup a sshpiper server using
bitbucket -> bitbucket@bitbucket.org:22 # ssh 127.0.0.1 -p 2222 -l bitbucket
github -> github@github.com:22 # ssh 127.0.0.1 -p 2222 -l github
gitlab -> gitlab@gitlab.com:22 # ssh 127.0.0.1 -p 2222 -l gitlab
connect to gitlab
$ ssh 127.0.0.1 -p 2222 -l gitlab
Permission denied (publickey).
connect to github.com
$ ssh 127.0.0.1 -p 2222 -l github
Permission denied (publickey).
sshpiper provides 3 pluginable components to highly customize your piper
sshpiperd daemon -h to learn more
Upstream driver helps sshpiper to find which upstream host to connect and how to connect.
For example, you can change the username when connecting to upstream sshd by config upstream driver
Available Upstream Drivers
-
Working Dir is a /home-like directory. SSHPiperd read files from workingdir/[username]/ to know upstream's configuration.
-
Database upstream driver connected to popular databases, such as mysql, pg or sqlite etc to provide upstream's information.
During SSH publickey auth, RFC 4252 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.
To support publickey auth, sshpiper will modify the sig using a private key provided by upstream driver.
e.g. (id_rsa) in the workingdir/[username]/.
How this work
+------------+ +------------------------+
| | | |
| client | | SSH Piper |
| PK_X +--------> | |
| | | v |
| | | Check PK_X |
+------------+ | in authorized_keys |
| | |
| | | +----------------+
| v | | |
| sign agian | | server |
| using PK_Y +--------------> check PK_Y |
| | | |
| | | |
+------------------------+ +----------------+
e.g.
on client
ssh-copy-id -i PK_X test@sshpiper
on ssh piper server
ln -s ~test/.ssh/authorized_keys workingdir/test/authorized_keys
ssh-keygen -N '' -f workingdir/test/id_rsa # this is PK_Y
ssh-copy-id -i workingdir/test/id_rsa test@server
now ssh test@sshpiper -i -i PK_X, sshpiper will send PK_Y to server instead of PK_X.
sshpiper allows you to add your own challenge before dialing to the upstream.
if a client failed in this challenge, connection will be closed.
however, the client has to pass the upstream server's auth in order to establish the whole connection.
Additional Challenge is required, but not enough.
This is useful when you want use publickey and something like google-authenticator together. OpenSSH do not support use publickey and other auth together.
-
pam
Linux-PAM challenger
this module use the pam service called
sshpiperdyou can configure the rule at
/etc/pam.d/sshpiperd -
azdevcode
Support Azure AD device code grant, More info
sshpier will ask user to login using webpage
To sign in, use a web browser to open the page https://microsoft.com/devicelogin and enter the code ****** to authenticate. -
authy
Support token and onetouch from https://authy.com/
Auditor provides hook for messages transfered by SSH Piper which cloud log messages onto disks or filter some specific message on the fly.
-
SSH Session logging (
--auditor-driver=typescript-logger)When
record_typescriptis allowed, each piped connection would be recorded into typescript in--auditor-typescriptlogger-outputdir.The file format is compatible with scriptreplay(1)
Example:
$ ./sshpiperd daemon --auditor-driver=typescript-logger ssh user_name@127.0.0.1 -p 2222 ... do some commands exit $ cd workingdir/user_name $ ls *.timing *.typescript 1472847798.timing 1472847798.typescript $ scriptreplay -t 1472847798.timing 1472847798.typescript # will replay the ssh session
SSH Piper comes with tools to list/add/remove pipes.
sshpiperd pipe -h to learn more.
MIT