nixpkgs/nixos/modules/virtualisation/ec2-data.nix
Masum Reza 184957277e
Merge pull request #322282 from tylerjl/tylerjl/print-host-key-soft-fail
nixos/ec2-data: skip unrecognized keys in print-host-keys
2024-07-31 10:59:10 +05:30

92 lines
3.3 KiB
Nix

# This module defines a systemd service that sets the SSH host key and
# authorized client key and host name of virtual machines running on
# Amazon EC2, Eucalyptus and OpenStack Compute (Nova).
{ config, lib, pkgs, ... }:
with lib;
{
imports = [
(mkRemovedOptionModule [ "ec2" "metadata" ] "")
];
config = {
systemd.services.apply-ec2-data =
{ description = "Apply EC2 Data";
wantedBy = [ "multi-user.target" "sshd.service" ];
before = [ "sshd.service" ];
after = ["fetch-ec2-metadata.service"];
path = [ pkgs.iproute2 ];
script =
''
${optionalString (config.networking.hostName == "") ''
echo "setting host name..."
if [ -s /etc/ec2-metadata/hostname ]; then
${pkgs.nettools}/bin/hostname $(cat /etc/ec2-metadata/hostname)
fi
''}
if ! [ -e /root/.ssh/authorized_keys ]; then
echo "obtaining SSH key..."
mkdir -m 0700 -p /root/.ssh
if [ -s /etc/ec2-metadata/public-keys-0-openssh-key ]; then
(umask 177; cat /etc/ec2-metadata/public-keys-0-openssh-key >> /root/.ssh/authorized_keys)
echo "new key added to authorized_keys"
fi
fi
# Extract the intended SSH host key for this machine from
# the supplied user data, if available. Otherwise sshd will
# generate one normally.
userData=/etc/ec2-metadata/user-data
mkdir -m 0755 -p /etc/ssh
if [ -s "$userData" ]; then
key="$(sed 's/|/\n/g; s/SSH_HOST_DSA_KEY://; t; d' $userData)"
key_pub="$(sed 's/SSH_HOST_DSA_KEY_PUB://; t; d' $userData)"
if [ -n "$key" -a -n "$key_pub" -a ! -e /etc/ssh/ssh_host_dsa_key ]; then
(umask 077; echo "$key" > /etc/ssh/ssh_host_dsa_key)
echo "$key_pub" > /etc/ssh/ssh_host_dsa_key.pub
fi
key="$(sed 's/|/\n/g; s/SSH_HOST_ED25519_KEY://; t; d' $userData)"
key_pub="$(sed 's/SSH_HOST_ED25519_KEY_PUB://; t; d' $userData)"
if [ -n "$key" -a -n "$key_pub" -a ! -e /etc/ssh/ssh_host_ed25519_key ]; then
(umask 077; echo "$key" > /etc/ssh/ssh_host_ed25519_key)
echo "$key_pub" > /etc/ssh/ssh_host_ed25519_key.pub
fi
fi
'';
serviceConfig.Type = "oneshot";
serviceConfig.RemainAfterExit = true;
};
systemd.services.print-host-key =
{ description = "Print SSH Host Key";
wantedBy = [ "multi-user.target" ];
after = [ "sshd.service" ];
script =
''
# Print the host public key on the console so that the user
# can obtain it securely by parsing the output of
# ec2-get-console-output.
echo "-----BEGIN SSH HOST KEY FINGERPRINTS-----" > /dev/console
for i in /etc/ssh/ssh_host_*_key.pub; do
${config.programs.ssh.package}/bin/ssh-keygen -l -f $i || true > /dev/console
done
echo "-----END SSH HOST KEY FINGERPRINTS-----" > /dev/console
'';
serviceConfig.Type = "oneshot";
serviceConfig.RemainAfterExit = true;
};
};
}