OpenSSH features reach their limit when it comes to industrialization. We don’t want an administrator to sign every user’s public key by hand every day, so we need a service for that. That is exactly the purpose of CASSH: signing keys! Developped for @leboncoin
https://medium.com/leboncoin-engineering-blog/cassh-ssh-key-signing-tool-39fd3b8e4de7
- CLI version : 1.8.1 (02/06/2022)
+
- WebUI version : 1.3.1 (02/06/2022)
- Server version : 2.3.1 (06/03/2022)
+
Add new key to cassh-server :
cassh add
Sign pub key :
cassh sign [--display-only] [--force]
Get public key status :
cassh status
Get ca public key :
cassh ca
Get ca krl :
cassh krl
usage: cassh admin [-h] [-s SET] [--add-principals ADD_PRINCIPALS]
[--remove-principals REMOVE_PRINCIPALS]
[--purge-principals]
[--update-principals UPDATE_PRINCIPALS]
[--principals-filter PRINCIPALS_FILTER]
username action
positional arguments:
username Username of client's key, if username is 'all' status
return all users
action Choice between : active, delete, revoke, set, search,
status keys
optional arguments:
-h, --help show this help message and exit
-s SET, --set SET CAUTION: Set value of a user.
--add-principals ADD_PRINCIPALS
Add a list of principals to a user, should be
separated by comma without spaces.
--remove-principals REMOVE_PRINCIPALS
Remove a list of principals to a user, should be
separated by comma without spaces.
--purge-principals Purge all principals to a user.
--update-principals UPDATE_PRINCIPALS
Update all principals to a user by the given
principals, should be separated by comma without
spaces.
--principals-filter PRINCIPALS_FILTER
Look for users by the given principals filter, should
be separated by comma without spaces.
Active Client username key :
cassh admin <username> active
Revoke Client username key :
cassh admin <username> revoke
Delete Client username key :
cassh admin <username> delete
Status Client username key :
cassh admin <username> status
Set Client username key :
# Set expiry to 7 days
cassh admin <username> set --set='expiry=7d'
# Add principals to existing ones
cassh admin <username> set --add-principals foo,bar
# Remove principals from existing ones
cassh admin <username> set --remove-principals foo,bar
# Update principals and erease existsing ones
cassh admin <username> set --update-principals foo,bar
# Purge principals
cassh admin <username> set --purge-principals
Search Principals among clients :
cassh admin all search --principals-filter foo,bar
Install docker : https://docs.docker.com/engine/installation/
# install utilities needed by tests/test.sh
sudo apt install pwgen jq
# Make a 'sudo' only if your user doesn't have docker rights, add your user into docker group
pip install -r tests/requirements.txt
cp tests/cassh/cassh.conf.sample tests/cassh/cassh.conf
cp tests/cassh/ldap_mapping.json.sample tests/cassh/ldap_mapping.json
# Edit cassh.conf file to configure the hosts
# Generate temporary certificates
mkdir test-keys
ssh-keygen -C CA -t rsa -b 4096 -o -a 100 -N "" -f test-keys/id_rsa_ca # without passphrase
ssh-keygen -k -f test-keys/revoked-keys
############################################
# BEGIN THE ONE OR MULTIPLE INSTANCES STEP #
############################################
# Duplicate the cassh.conf
cp tests/cassh/cassh.conf tests/cassh/cassh_2.conf
# Generate another krl
ssh-keygen -k -f test-keys/revoked-keys-2
sed -i "s/revoked-keys/revoked-keys-2/g" tests/cassh/cassh_2.conf# Launch this on another terminal
bash tests/launch_demo_server.sh --server_code_path ${PWD} --debug
$ /opt/cassh/src/server/server.py --config /opt/cassh/tests/cassh/cassh.conf
# When 'http://0.0.0.0:8080/' appears, start this script
bash tests/test.shThe same as previsouly, but launch this to specify a second cassh-server instance
# Launch this on another terminal
bash tests/launch_demo_server.sh --server_code_path ${PWD} --debug --port 8081
$ /opt/cassh/src/server/server.py --config /opt/cassh/tests/cassh/cassh_2.confGenerate key pair then sign it !
git clone https://github.com/nbeguier/cassh.git /opt/cassh
cd /opt/cassh
# Generate key pair
mkdir test-keys
ssh-keygen -t rsa -b 4096 -o -a 100 -f test-keys/id_rsa
rm -f ~/.cassh
cat << EOF > ~/.cassh
[user]
name = user
key_path = ${PWD}/test-keys/id_rsa
key_signed_path = ${PWD}/test-keys/id_rsa-cert
url = http://localhost:8080
[ldap]
realname = [email protected]
EOF
# List keys
python cassh status
# Add it into server
python cassh add
# ADMIN: Active key
python cassh admin user active
# Sign it !
python cassh sign [--display-only]Licensed under the Apache License, Version 2.0 (the "License").
Copyright 2017-2025 Nicolas BEGUIER; (nbeguier - nicolas_beguier[at]hotmail[dot]com)