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trezor-agent/doc/README-SSH.md

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Screencast demo usage

Simple usage (single SSH session)

Demo

Advanced usage (multiple SSH sessions from a sub-shell)

This feature allows using regular SSH-related commands within a subprocess running user's shell. SSH_AUTH_SOCK environment variable is defined for the subprocess (pointing to the SSH agent, running as a parent process). This way the user can use SSH-related commands (e.g. ssh, ssh-add, sshfs, git, hg), while authenticating via the hardware device. Subshell

Loading multiple SSH identities from configuration file

Config

Public key generation

Run:

/tmp $ trezor-agent user@ssh.hostname.com -v > hostname.pub
2015-09-02 15:03:18,929 INFO         getting "ssh://user@ssh.hostname.com" public key from Trezor...
2015-09-02 15:03:23,342 INFO         disconnected from Trezor
/tmp $ cat hostname.pub
ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBGSevcDwmT+QaZPUEWUUjTeZRBICChxMKuJ7dRpBSF8+qt+8S1GBK5Zj8Xicc8SHG/SE/EXKUL2UU3kcUzE7ADQ= ssh://user@ssh.hostname.com

Append hostname.pub contents to /home/user/.ssh/authorized_keys configuration file at ssh.hostname.com, so the remote server would allow you to login using the corresponding private key signature.

Usage

Run:

/tmp $ trezor-agent user@ssh.hostname.com -v -c
2015-09-02 15:09:39,782 INFO         getting "ssh://user@ssh.hostname.com" public key from Trezor...
2015-09-02 15:09:44,430 INFO         please confirm user "roman" login to "ssh://user@ssh.hostname.com" using Trezor...
2015-09-02 15:09:46,152 INFO         signature status: OK
Linux lmde 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt11-1+deb8u3 (2015-08-04) x86_64

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Tue Sep  1 15:57:05 2015 from localhost
~ $

Make sure to confirm SSH signature on the Trezor device when requested.

Accessing remote Git/Mercurial repositories

Use your SSH public key to access your remote repository (e.g. GitHub):

$ trezor-agent -v -e ed25519 git@github.com | xclip

Use the following Bash alias for convenient Git operations:

$ alias git_hub='trezor-agent -v -e ed25519 git@github.com -- git'

Replace git with git_hub for remote operations:

$ git_hub push origin master

The same works for Mercurial (e.g. on BitBucket):

$ trezor-agent -v -e ed25519 git@bitbucket.org -- hg push

Troubleshooting

If SSH connection fails to work, please open an issue with a verbose log attached (by running trezor-agent -vv) .

Incompatible SSH options

Note that your local SSH configuration may ignore trezor-agent, if it has IdentitiesOnly option set to yes.

 IdentitiesOnly
         Specifies that ssh(1) should only use the authentication identity files configured in
         the ssh_config files, even if ssh-agent(1) or a PKCS11Provider offers more identities.
         The argument to this keyword must be “yes” or “no”.
         This option is intended for situations where ssh-agent offers many different identities.
         The default is “no”.

If you are failing to connect, try running:

$ trezor-agent -vv user@host -- ssh -vv -oIdentitiesOnly=no user@host

Start the agent as a systemd unit

1. Create these files in ~/.config/systemd/user

Replace trezor with keepkey or ledger as required.

trezor-ssh-agent.service
[Unit]
Description=trezor-agent SSH agent
Requires=trezor-ssh-agent.socket

[Service]
Type=Simple
ExecStart=/usr/bin/trezor-agent --foreground --sock-path %t/trezor-agent/S.ssh IDENTITY

Replace IDENTITY with the identity you used when exporting the public key.

trezor-ssh-agent.socket
[Unit]
Description=trezor-agent SSH agent socket

[Socket]
ListenStream=%t/trezor-agent/S.ssh
FileDescriptorName=ssh
Service=trezor-ssh-agent.service
SocketMode=0600
DirectoryMode=0700

[Install]
WantedBy=sockets.target
2. Run
systemctl --user start trezor-ssh-agent.service trezor-ssh-agent.socket
systemctl --user enable trezor-ssh-agent.socket
3. Add this line to your .bashrc or equivalent file:
export SSH_AUTH_SOCK=$(systemctl show --user --property=Listen trezor-ssh-agent.socket | grep -o "/run.*")
4. SSH will now automatically use your device key in all terminals.