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#!/usr/bin/python3
import argparse
import os
import subprocess
import tempfile
import yaml
def log(msg):
if True:
print(msg)
class Config:
defaults = {
"authorized_keys_file": None,
"host_cert_file": None,
"host_key_file": None,
"user_ca_pub_file": None,
}
exandable = [
"authorized_keys_file",
"host_cert_file",
"host_key_file",
"user_ca_pub_file",
]
def __init__(self):
self.config = dict(self.defaults)
def __getitem__(self, key):
return self.config[key]
def read(self, filename):
log(f"reading configuration from {filename}")
with open(filename) as f:
obj = yaml.safe_load(f)
self.config.update(obj)
for key in self.exandable:
if self.config[key] is not None:
self.config[key] = os.path.expanduser(self.config[key])
log(f"config: {self.config}")
def mount(drive, mp):
log(f"mounting {drive} on {mp}")
subprocess.run(["mount", drive, mp])
def unmount(path):
log(f"un-mounting {path}")
subprocess.run(["umount", path])
def cat(path):
log(f"reading {path}")
with open(path) as f:
return f.read()
def write(path, content, owner, group, mode):
log(f"writing {path}")
with open(path, "w") as f:
f.write(content)
os.chown(path, owner, group)
os.chmod(path, mode)
def dir_exists(mp, path):
full = os.path.join(mp, path)
if not os.path.exists(full):
raise Exception(f"{full} does not exist")
def host_id(config, mp):
key_path = config["host_key_file"]
cert_path = config["host_cert_file"]
if key_path is None or cert_path is None:
return
key = cat(key_path)
cert = cat(cert_path)
config_d = "/etc/ssh/sshd_config.d"
host_key = "/etc/ssh/ssh_host_key"
host_cert = "/etc/ssh/ssh_host_key-cert.pub"
# Note that the order of HostKey and HostCertificate lines matter.
write(
f"{mp}{config_d}/id.conf",
f"""
HostKeyAlgorithms ssh-ed25519
HostKey {host_key}
HostCertificate {host_cert}
""",
0,
0,
0o644,
)
write(f"{mp}{host_key}", key, 0, 0, 0o600)
write(f"{mp}{host_cert}", cert, 0, 0, 0o644)
def authorized_keys(config, mp):
authz_keys_path = config["authorized_keys_file"]
if authz_keys_path is None:
return
authz_keys = cat(authz_keys_path)
write(f"{mp}/root/.ssh/authorized_keys", authz_keys, 0, 0, 0x600)
def user_ca(config, mp):
ca_path = config["user_ca_pub_file"]
if ca_path is None:
return
ca_key = cat(ca_path)
include = f"{mp}/etc/ssh/sshd_config.d/userca.conf"
write(include, "TrustedUserCAKeys /etc/ssh/user_ca_keys\n", 0, 0, 0o644)
cakeys = f"{mp}/etc/ssh/user_ca_keys"
write(cakeys, ca_key, 0, 0, 0o644)
def main():
log("configure-image starting")
p = argparse.ArgumentParser()
p.add_argument("config", metavar="FILE", help="configuration file")
p.add_argument(
"drive",
metavar="DEVICE",
help="device file of the drive with v-i installer image",
)
args = p.parse_args()
config = Config()
config.read(args.config)
mp = tempfile.mkdtemp()
drive1 = f"{args.drive}1"
drive2 = f"{args.drive}2"
mount(drive2, mp)
try:
dir_exists(mp, "etc/ssh")
host_id(config, mp)
authorized_keys(config, mp)
user_ca(config, mp)
finally:
unmount(mp)
os.rmdir(mp)
log("all good")
main()
|
