SSH-AGENT KEEPALIVE

SSH-AGENT KEEPALIVE manages ssh-agent for you so that you have access to your agent in every terminal session.

TL;DR

Quick Setup

• Setup SSH-AGENT-KEEPALIVE by running setup.sh.
• Attach to the SSH-agent in old terminal windows by running source ~/.ssh/env. Alternatively you can source ~/.bash_profile which will attach to your newly spawned SSH-Agent.
• See Example flow of a first time setup below for detailed output

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Why use SSH-AGENT KEEPALIVE?

1. Because ssh-agent makes your remote access life easier
2. Alternative is to source your agent environment manually or source it directly from your ~/.bash_profile but what happens when that pid dies and the cache lives?
3. You can write your own logic to see if the pid is still there but occasionally you'll find that you have more than one ssh-agent process running for your user which is wasting resources. I've considered those things and accounted for them.

Setup

• IMPORTANT Remove any logic from your ~/.bash_profile that starts ssh-agent or invokes ssh-add
• Run ./setup.sh which takes the following actions.
• Verifies ~/.bash_profile doesn't directly invoke ssh-agent or ssh-add
• Backs up ~/.bash_profile to ~/.bash_profile~
• Adds all private keys found in ~/.ssh to a variable named SSH_KEYS
• Updates your ~/.bash_profile to install itself
• Checks if ~/.ssh/config exists
• If so it checks if ForwardAgent is set to no then asks for permission to change this. You should only deny permission if you purposely don't want agent forwarding for that host.
• If not it creates a basic ssh_config with ForwardAgent yes configured for wildcard Host *

Additonal considerations:

• For supreme laziness you may want to consider using connection multiplexing. "would ya look at that?"- This is disabled on some SSH servers due to "security concerns" ^-(as Ed Bassmaster)--^

SSH Connection Multiplexing via Control Sockets

I've provided an example ssh_config in this directory that implements connection multiplexing. It uses multiplexing based on hostname and persists for 15 minutes after you log out.

Host *
    ControlMaster auto
    ControlPath ~/.ssh/ctrl-%h
    ControlPersist 15m
    ForwardAgent yes
    IdentityFile ~/.ssh/<SSH_KEY_HERE>
    User <USERNAME HERE>

Refer to man 5 ssh_config for help setting up your ssh_config.

Example flow of a first time setup

# Example output, first try failed:
user@host:~/git/ssh-agent-keepalive$ ./setup.sh
[W] WARNING:
    You still have logic in your /Users/user/.bash_profile invoking ssh-agent and/or ssh-add
    Please remove this from your /Users/user/.bash_profile before installing.

[i] SSH-AGENT-KEEPALIVE works by modifying your /Users/user/.bash_profile to manage ssh-agent
    and ssh-add by itself

user@host:~/git/ssh-agent-keepalive$ vim ~/.bash_profile # Removing ssh-agent and ssh-add invocations

user@host:~/git/ssh-agent-keepalive$ ./setup.sh
[!] Ran `echo declare -a SSH_KEYS=(~/.ssh/id_ed25519 ~/.ssh/id_rsa) >> /Users/user/.bash_profile`
[!] Ran `tail -n +2 keepalive >> /Users/user/.bash_profile`
[i] You have agent forwarding enabled!
[!] Done, SSH-AGENT-KEEPALIVE is enabled

Example output

Last login: Wed May  3 19:15:41 on ttys079
[+] Starting ssh agent...
[!] Saved ssh env at /Users/user/.ssh/env, agent pid 83610
Enter passphrase for /Users/user/.ssh/priv1:
Identity added: /Users/user/.ssh/priv1 (<censored>)
Enter passphrase for /Users/user/.ssh/priv2:
Identity added: /Users/user/.ssh/priv2 (<censored>)
Enter passphrase for /Users/user/.ssh/github/priv3:
Identity added: /Users/user/.ssh/github/priv3 (<censored>)

Last login: Wed May  3 19:15:45 on ttys080
[!] Found running ssh-agent(s)...
[!] Found cached ssh-agent env, sourcing...
[!] Attached to cached ssh-agent

Last login: Wed May  3 19:18:20 on ttys081
[!] Found running ssh-agent(s)...
[!] Found cached ssh-agent env, sourcing...
[X] Killed stale ssh-agent with pid 71874
[X] Killed stale ssh-agent with pid 71876
[X] Killed stale ssh-agent with pid 71878
[X] Killed stale ssh-agent with pid 71880
[!] Attached to cached ssh-agent