cbas 156

Command line interface to the c-bastion

Table of Contents

• About

• Install

• Quickstart

• Usage

• Config-File

• License

About

This is the command line interface to the *c-bastion* jump host. It allows you to upload an ssh-key-file and create a user on the jump-host, so that you can log into it. It requires an initial connection to auth-server to obtain an (open-id-connect) access token.

The basic flow is as follows:

+-----------------+  +-----------------+  +-----------------+
|                 |  |                 |  |                 |
|    developer    |  |    jump host    |  |   auth server   |
|                 |  |                 |  |                 |
+--------+--------+  +--------+--------+  +--------+--------+
         |                    |                    |
         +----------------------------------------->
         | request token      |                    |
         <-----------------------------------------+
         | receive token      |                    |
         |                    |                    |
         +-------------------->                    |
         | upload key         +-------------------->
         |                    | validate token     |
         |                    <--------------------+
         <--------------------+                    |
         | upload OK          |                    |
         |                    |                    |
         +-------------------->                    |
         | ssh log in         |                    |
         |                    |                    |
         |                    |                    |
         |                    |                    |
         +                    +                    +

Where developer is your local machine (desktop, laptop, etc..) auth server is the auth-server and jump host is the jump host. cbas takes care of obtaining the token and uploading the ssh-key.

Install

Use the Python standards, for example:

$ pip install cbas

Quickstart

1. Install the software.

2. Ask one of your colleagues for the auth-host, client-secret and jump-host parameters.

3. Then run the following to upload your key:

   $ cbas -a <AUTH-host> -s <CLIENT-SECRET> -h <JUMP-HOST> upload
   ...

4. Then you should be able to login, using:

   $ ssh <JUMP-HOST>
   ...

Usage

$ cbas --help
Usage: cbas [OPTIONS] COMMAND [ARGS]...

Options:
  -v, --verbose                   Activate verbose mode.
  -c, --config <config_path>      Path to config file. Default: '~/.cbas'.
  -u, --username <username>       Username. Default: the logged in user.
  -k, --ssh-key-file <key-file>   SSH Identity to use. Default:
                                  '~/.ssh/id_rsa.pub'.
  -p, --password-provider <provider>
                                  Password provider. Default: 'prompt'.
  -s, --client-secret <secret>    Special client secret, ask mum.
  -a, --auth-host <host>          Auth-server host.
  -h, --jump-host <host>          Jump host to connect with.
  --version                       Print version and exit.
  --help                          Show this message and exit.

Commands:
  delete  Delete user.
  dry_run Dry run, sanitize all config only.
  upload  Upload ssh-key and create user.

Options

verbose

This switch activates verbose output, useful in case you are debugging

config

The path to the config file. Note, since we are using the yamlreader package, this could also be a directory with multiple config files. Also, the config is in YAML syntax, see below.

username

The username when communicating with the auth-server. Note that the returned token contains the authenticated username which is subsequently sent to the jump-host. Thus you will not be able to create arbitrary users on the jump-host

ssh-key-file

Path to the public ssh-key-file. This will be uploaded to the jump-host.

password-provider

Where to get the password from. Valid values are prompt and keyring (and testing). prompt will always ask for a password, whereas keyring will ask exactly once and then store the password in the system keyring.

auth-host

The hostname of the auth-server. E.g auth-server.example. (Note that, by default this will use https:// as scheme and /oauth/token as endpoint. However, explict urls, e.g. http://auth-server.example and explicit endpoints e.g. auth-server.example/special/id/auth are tolerated.)

client-secret

A special client secret string needed when communicating with the auth-server.

jump-host

The hostname of the jump-host. E.g. jump-host.example. (Note that, by default this will use https://. However, explict urls, e.g. http://jump-host.example are tolerated.)

version

Display version number and exit.

help

Display help and exit.

Subcommands

upload

Upload ssh-key-file and create user.

dry_run

Sanitize and aggregate all options from config-file and command-line. Don’t connect to anything.

delete

Delete your user again. For example: if you uploaded the wrong ssh-key-file.

Config-File

cbas is equipped with a powerful configuration mechanism. All relevant parameters that can be supplied on the command-line can also be supplied in the config-file, for example:

username: acid_burn
ssh-key-file: ~/.ssh/mykey_rsa.pub
auth-host auth-server.example
client-secret: mysupersecret
password-provider: keyring
jump-host: jump-host.example

Please note that, any parameters supplied on the command line will take precedence over those supplied via the config-file. If in doubt, try using the --verbose switch.

License

Copyright 2016 Immobilien Scout GmbH

Licensed under the Apache License, Version 2.0 (the “License”); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.