ocsh 20230908.post3

SSH password log-in and command automator

ocsh - SSH password log-in and command automator

ocsh automates SSH password login and command execution through annotations on ssh_config(5) Hosts:

• password authentication, reading password from pass[1]:
  • config: # ocsh pass <pass-name>
  • command: $ ocsh host
• post-login command execution:
  • config: # ocsh post <action> "<cmd>"
  • command: $ ocsh host[action]
• post-login command execution, reading additional password from pass[1]:
  • config: # ocsh postpass <action> "<cmd>" <pass-name>
  • command: $ ocsh host[action]
• use different ssh command or prefix by other command:
  • config: # ocsh cmd "<ssh-command>"
  • config: # ocsh pre "<pre-command>"
  • command: $ ocsh host

[1] https://www.passwordstore.org/

Compatibility with OpenSSH is kept as much as possible:

• support usual SSH aliases, keys and command-line options
• compatible with rsync, scp and other tools using SSH for transport, see example commands
• autocompletion can be set-up with --ocsh-install-autocompletion

Usage

usage: ocsh.py [-h] [--ocsh-verbose] [--ocsh-pretend] [--ocsh-examples]
               [--ocsh-install-autocompletion]
               [destination] ...

ocsh - SSH password log-in and command automator

positional arguments:
  destination           host[action]
  args                  any OpenSSH options or remote command

options:
  -h, --help            show this help message and exit
  --ocsh-verbose        enable debug messages
  --ocsh-pretend        do not actually perform the connection
  --ocsh-examples       show example ocsh configuration and commands
  --ocsh-install-autocompletion
                        install bash autocompletion for the current user

Installation

pip install ocsh

Examples of usage

# connect to SSH alias 'host1' with automated password login
# ssh_config(5)
Host host1
   Hostname 10.0.0.1
   User minou
   # ocsh pass pass-location                 # location in password-store
# command
ocsh host1
# equivalent ssh command
sshpass -p "$(pass pass-location)" ssh host1

# connect to SSH alias 'host2' with automated password login, going through the above 'host1', and become root
# ssh_config(5)
Host host2
    Host 10.9.0.1
    User root
    # ocsh pass pass-location2               # location in password-store
    # ocsh postpass su "su -l" pass-location3
    # ocsh post nsep "ip netns exec nsep"    # post-login command to enter a network namespace
# command
ocsh host2[root]
# equivalent ssh command
sshpass -p "$(pass pass-location2)" ssh -oProxyCommand="sshpass -p "$(pass pass-location1)" ssh host1" host2 su -l
<now enter root password (from pass-location3) manually>

# run ssh connection from a different namespace
# ssh_config(5)
Host host1
   Hostname 10.0.0.1
   User minou
   # ocsh pre "ip netns exec toto"
# command
ocsh host1
# equivalent command
ip netns exec ssh host1

# run rsync through ocsh from host1 with automated password login
rsync -e "ocsh" -avP host1:/etc/hosts /tmp/

# run scp through ocsh from host1 with automated password login
scp -S "ocsh" host1:/etc/hosts /tmp/

See also

• netmiko - python library to SSH to various network devices https://github.com/ktbyers/netmiko
• sshpass - automate SSH password-based log-in https://github.com/kevinburke/sshpass
• passh - sshpass alternative to automate SSH password-based log-in https://github.com/clarkwang/passh