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README.md

glome-login

This binary implements the client side of the GLOME Login protocol. It is written to be a replacement of login(1).

Usage

  1. Create a configuration file, see example.cfg.
  2. Try it out by running glome-login -c glome.cfg -- root

Configuration

In order to reduce external dependencies, a custom parser is used to read the configuration file. The parser supports a simplified version of the INI syntax with the following limitations:

  • Quoting and escaping is not supported.
  • Comments are allowed only at the start of the line and can begin with either # or ;.

Installation

The installation is dependent on what system you are running.

systemd

Create a override file for the getty instance e.g. in /etc/systemd/system/serial-getty@.service.d/glome.conf.

[Service]
ExecStart=
ExecStart=-/sbin/agetty -l /usr/local/sbin/glome-login \
  -o '-- \\u' --keep-baud 115200,38400,9600 %I $TERM

Alternatively or for a normal VTY, use /etc/systemd/system/getty@.service.d/glome.conf.

[Service]
ExecStart=
ExecStart=-/sbin/agetty -l /usr/local/sbin/glome-login \
  -o '-- \\u' --noclear %I $TERM

Troubleshooting

glome-login uses error tags to communicate errors.

no-service-key

This error means that glome-login could not figure out what service key to use. This most likely means that you have not specified a service key in the configuration file (by default /etc/glome/config).

PAM module

pam_glome.so library implements the PAM authentication module for the GLOME Login protocol.

Installation

  1. Install the library into the system dependent location for PAM modules (for example /lib/security/pam_glome.so).
  2. Enable and configure PAM module for a specific service (for example /etc/pam.d/login):
auth       requisite  pam_glome.so

Usage

PAM module supports the following options:

  • config_path=PATH - location of the configuration file to parse (defaults to /etc/glome/config)
  • key=KEY - use hex-encoded KEY as the service key (defaults to key from configuration file)
  • key_version=N - use N for the service key version (defaults to key version from configuration file)
  • prompt=PROMPT - challenge prompt (defaults to prompt from configuration file)
  • debug - enable verbose logging
  • print_secrets - enable logging of secrets (INSECURE!)
  • host_id=NAME - use NAME as the host-id
  • ephemeral_key=KEY - use hex-encoded KEY instead of the ephemeral secret key (INSECURE!)

Troubleshooting

PAM module uses error tags to communicate errors in the syslog messages.

Docker

Dockerfile included in the repository creates a Docker image that can be used to test glome-login and the PAM module.

Instalation

Docker image for GLOME needs to be built first using the following command:

$ docker build -t glome -f kokoro/docker/Dockerfile .

Usage

Container is than started in the background with two TCP ports published to the host:

$ container=$(docker run -d -p 2022:22 -p 2023:23 glome)

Once the container is running it is possible to login using netcat or socat, for example:

$ socat tcp-connect:localhost:2023 file:`tty`,raw,echo=0

Regular SSH client can be used for testing the PAM module:

$ ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -p 2022 root@localhost

Authorization code required for GLOME Login can be obtained by running:

$ docker exec $container /usr/local/bin/glome login --key /usr/local/etc/glome/private.key https://glome.example.com/v1/...