veilid/scripts/earthly/secretsd/secretsd/external_keys.py
2022-01-09 15:17:36 -05:00

107 lines
3.9 KiB
Python

# This module can load passwords from external sources, such as files or
# environment variables or KWallet (and no, *not* libsecret -- as much as I
# want to use the nifty gi-based libsecret API...).
#
# It deals with strings (the lowest common denominator), but it's really meant
# to be used for storing Base64-encoded keys and not raw passwords.
import dbus
import os
import re
import subprocess
class KWalletClient():
app_id = "org.eu.nullroute.Secretsd"
folder = "Passwords"
def __init__(self):
self.bus = dbus.SessionBus()
self.mgr = self.bus.get_object("org.kde.kwalletd5", "/modules/kwalletd5")
self.mgr = dbus.Interface(self.mgr, "org.kde.KWallet")
def __enter__(self):
self.wallet = self.mgr.localWallet()
self.handle = self.mgr.open(self.wallet, 0, self.app_id)
return self
def __exit__(self, *argv):
self.mgr.disconnectApplication(self.wallet, self.app_id)
def get_password(self, name):
if self.mgr.hasEntry(self.handle, self.folder, name, self.app_id):
return str(self.mgr.readPassword(self.handle, self.folder, name, self.app_id))
else:
raise KeyError(name)
def set_password(self, name, value):
self.mgr.writePassword(self.handle, self.folder, name, value, self.app_id)
def _parse_specifier(source):
m = re.match(r"^(\w+):(.*)", source)
if m:
return m.groups()
else:
# Too easy to end up saving keys in a file named 'kwallet'...
#return "file", source
raise ValueError("key location must be specified as 'type:rest'")
def load_ext_key(source):
kind, rest = _parse_specifier(source)
if kind == "env":
return os.environ[rest]
elif kind == "exec":
res = subprocess.run(rest, shell=True,
stdin=subprocess.DEVNULL,
stdout=subprocess.PIPE,
check=True)
return res.stdout.decode().strip()
elif kind == "file":
with open(rest, "r") as fh:
return fh.read().strip()
elif kind == "kwallet":
with KWalletClient() as kw:
return kw.get_password(rest or "secretsd master key")
elif kind == "libsecret":
raise ValueError("cannot load external key from myself")
else:
raise ValueError("unknown external key source %r" % kind)
def store_ext_key(source, key):
kind, rest = _parse_specifier(source)
if kind == "env":
raise ValueError("environment is volatile storage, cannot store keys there")
elif kind == "exec":
# XXX: Should there be a way to distinguish whether the command is
# invoked for load vs store, or should I just remove storing to exec:
# because this is an advanced operation and the user can just emulate
# it with a temporary file?
res = subprocess.run(rest, shell=True,
input=key.encode(),
check=True)
elif kind == "file":
with open(rest, "w", opener=lambda p, f: os.open(p, f, 0o400)) as fh:
fh.write(key)
elif kind == "kwallet":
with KWalletClient() as kw:
kw.set_password(rest or "secretsd master key", key)
elif kind == "libsecret":
raise ValueError("cannot store external key in myself")
else:
raise ValueError("unknown external key source %r" % kind)
if __name__ == "__main__":
import argparse
parser = argparse.ArgumentParser()
parser.add_argument("specifier")
parser.add_argument("--store-key", metavar="KEY", help="store the specified key (as text)")
args = parser.parse_args()
arg = args.specifier
if key := args.store_key:
print(f"Storing key {key!r} to {arg!r}")
store_ext_key(arg, key)
print(f"Retrieving key from {arg!r}")
key = load_ext_key(arg)
print(f"The key is {key!r}")