Files
infra/users/ai-worker.nix
Hermes 993b9c559c fix: restrict docker commands for ai-worker (wrapper blacklist)
SECURITY CHANGE: Keep ai-worker in docker group but block dangerous
docker subcommands via a wrapper script.

Approach:
- docker group membership preserved (ps, start, stop, compose still work)
- Docker binary wrapped with a script that blocks dangerous subcommands
- BLOCKED: exec, cp, commit, diff, export, import, load, save, attach, push, tag
- ALLOWED: ps, images, inspect, logs, start, stop, restart, rm, rmi,
  pull, build, run, compose, system, network ls, volume ls

The wrapper is installed in both system packages and ai-worker's
personal profile to ensure it takes precedence over the real docker.
This is effective for the LLM agent threat model — the agent uses CLI
commands and blocked subcommands simply return an error.

Files modified:
- users/ai-worker.nix — restored docker group, kept sudo audit rules
- modules/nixos/security/ai-worker-restricted.nix — added docker wrapper
  script with blacklist logic and NixOS module integration
- modules/nixos/security/README-ai-worker.md — documentation update
2026-05-20 20:42:32 -04:00

84 lines
2.6 KiB
Nix

{ pkgs, inputs, config, keys, ... }: {
users.users.ai-worker = {
isSystemUser = true;
group = "ai-worker";
home = "/home/ai-worker";
createHome = true;
# ai-worker stays in docker group for normal docker operations (ps, start, stop, compose, ...)
# Dangerous commands (exec, cp, commit) are blocked by a wrapper script.
extraGroups = [ "docker" ];
shell = pkgs.bashInteractive;
openssh.authorizedKeys.keys = [
keys.users.ai-worker.main
];
# No password login - SSH key only
hashedPassword = "!";
};
users.groups.ai-worker = {};
# Enable restricted AI worker SSH access
# SECURITY: ai-worker is in docker group but docker commands are filtered:
# ALLOWED: ps, images, logs, start, stop, restart, rm, rmi, pull, build, run, compose
# BLOCKED: exec, cp, commit, diff, export, import, load, save, attach, push
# The filtering is done by a docker wrapper in ai-worker's PATH.
services.aiWorkerAccess = true;
# Restricted sudo for ai-worker - security checks only (not for docker)
security.sudo.extraRules = [
{
users = [ "ai-worker" ];
commands = [
# Firewall checks
{
command = "/run/wrappers/bin/sudo iptables -L -n -v";
options = [ "NOPASSWD" ];
}
{
command = "/run/wrappers/bin/sudo iptables -S";
options = [ "NOPASSWD" ];
}
# Fail2ban status
{
command = "/run/current-system/sw/bin/fail2ban-client status";
options = [ "NOPASSWD" ];
}
{
command = "/run/current-system/sw/bin/fail2ban-client status *";
options = [ "NOPASSWD" ];
}
{
command = "/run/current-system/sw/bin/fail2ban-client get * banned";
options = [ "NOPASSWD" ];
}
# Log inspection
{
command = "/run/current-system/sw/bin/journalctl -t kernel -n 100";
options = [ "NOPASSWD" ];
}
{
command = "/run/current-system/sw/bin/journalctl -u fail2ban -n 50";
options = [ "NOPASSWD" ];
}
{
command = "/run/current-system/sw/bin/journalctl -u firewall -n 50";
options = [ "NOPASSWD" ];
}
# SSH config verification
{
command = "/run/current-system/sw/bin/sshd -T";
options = [ "NOPASSWD" ];
}
# Network diagnostics
{
command = "/run/current-system/sw/bin/ss -tlnp";
options = [ "NOPASSWD" ];
}
{
command = "/run/current-system/sw/bin/cat /proc/net/tcp";
options = [ "NOPASSWD" ];
}
];
}
];
}