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authorTomás Touceda <chiiph@leap.se>2013-05-30 10:28:52 -0300
committerTomás Touceda <chiiph@leap.se>2013-05-30 10:28:52 -0300
commitdbbf33d27268266088ee1ab15fc04cef33259250 (patch)
treeae3f597a456d1671aa1cdf334912b1422538c93b /src/leap/common/keymanager/openpgp.py
parent0a795cceb0f5902cb928b9b67bd91d0050459238 (diff)
parent7f35ec61513d4286bde08ba957945b38b85ca87a (diff)
Merge remote-tracking branch 'drebs/feature/2683-move-keymanager-to-leap_client' into develop0.2.5release/v0.2.5
Diffstat (limited to 'src/leap/common/keymanager/openpgp.py')
-rw-r--r--src/leap/common/keymanager/openpgp.py636
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diff --git a/src/leap/common/keymanager/openpgp.py b/src/leap/common/keymanager/openpgp.py
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-# -*- coding: utf-8 -*-
-# openpgp.py
-# Copyright (C) 2013 LEAP
-#
-# This program is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program. If not, see <http://www.gnu.org/licenses/>.
-
-"""
-Infrastructure for using OpenPGP keys in Key Manager.
-"""
-import logging
-import os
-import re
-import shutil
-import tempfile
-
-from leap.common.check import leap_assert, leap_assert_type
-from leap.common.keymanager import errors
-from leap.common.keymanager.keys import (
- EncryptionKey,
- EncryptionScheme,
- is_address,
- build_key_from_dict,
- KEYMANAGER_KEY_TAG,
- TAGS_ADDRESS_PRIVATE_INDEX,
-)
-from leap.common.keymanager.gpg import GPGWrapper
-
-logger = logging.getLogger(__name__)
-
-
-#
-# gpg wrapper and decorator
-#
-
-def temporary_gpgwrapper(keys=None):
- """
- Returns a unitary gpg wrapper that implements context manager
- protocol.
-
- :param key_data: ASCII armored key data.
- :type key_data: str
-
- :return: a GPGWrapper instance
- :rtype: GPGWrapper
- """
- # TODO do here checks on key_data
- return TempGPGWrapper(keys=keys)
-
-
-def with_temporary_gpg(fun):
- """
- Decorator to add a temporary gpg wrapper as context
- to gpg related functions.
-
- Decorated functions are expected to return a function whose only
- argument is a gpgwrapper instance.
- """
- def wrapped(*args, **kwargs):
- """
- We extract the arguments passed to the wrapped function,
- run the function and do validations.
- We expect that the positional arguments are `data`,
- and an optional `key`.
- All the rest of arguments should be passed as named arguments
- to allow for a correct unpacking.
- """
- if len(args) == 2:
- keys = args[1] if isinstance(args[1], OpenPGPKey) else None
- else:
- keys = None
-
- # sign/verify keys passed as arguments
- sign = kwargs.get('sign', None)
- if sign:
- keys = [keys, sign]
-
- verify = kwargs.get('verify', None)
- if verify:
- keys = [keys, verify]
-
- # is the wrapped function sign or verify?
- fun_name = fun.__name__
- is_sign_function = True if fun_name == "sign" else False
- is_verify_function = True if fun_name == "verify" else False
-
- result = None
-
- with temporary_gpgwrapper(keys) as gpg:
- result = fun(*args, **kwargs)(gpg)
-
- # TODO: cleanup a little bit the
- # validation. maybe delegate to other
- # auxiliary functions for clarity.
-
- ok = getattr(result, 'ok', None)
-
- stderr = getattr(result, 'stderr', None)
- if stderr:
- logger.debug("%s" % (stderr,))
-
- if ok is False:
- raise errors.EncryptionDecryptionFailed(
- 'Failed to encrypt/decrypt in %s: %s' % (
- fun.__name__,
- stderr))
-
- if verify is not None:
- # A verify key has been passed
- if result.valid is False or \
- verify.fingerprint != result.pubkey_fingerprint:
- raise errors.InvalidSignature(
- 'Failed to verify signature with key %s: %s' %
- (verify.key_id, stderr))
-
- if is_sign_function:
- # Specific validation for sign function
- privkey = gpg.list_keys(secret=True).pop()
- rfprint = result.fingerprint
- kfprint = privkey['fingerprint']
- if result.fingerprint is None:
- raise errors.SignFailed(
- 'Failed to sign with key %s: %s' %
- (privkey['keyid'], stderr))
- leap_assert(
- result.fingerprint == kfprint,
- 'Signature and private key fingerprints mismatch: '
- '%s != %s' %
- (rfprint, kfprint))
-
- if is_verify_function:
- # Specific validation for verify function
- pubkey = gpg.list_keys().pop()
- valid = result.valid
- rfprint = result.fingerprint
- kfprint = pubkey['fingerprint']
- if valid is False or rfprint != kfprint:
- raise errors.InvalidSignature(
- 'Failed to verify signature '
- 'with key %s.' % pubkey['keyid'])
- result = result.valid
-
- # ok, enough checks. let's return data if available
- if hasattr(result, 'data'):
- result = result.data
- return result
- return wrapped
-
-
-class TempGPGWrapper(object):
- """
- A context manager returning a temporary GPG wrapper keyring, which
- contains exactly zero or one pubkeys, and zero or one privkeys.
-
- Temporary unitary keyrings allow the to use GPG's facilities for exactly
- one key. This function creates an empty temporary keyring and imports
- C{keys} if it is not None.
- """
- def __init__(self, keys=None):
- """
- :param keys: OpenPGP key, or list of.
- :type keys: OpenPGPKey or list of OpenPGPKeys
- """
- self._gpg = None
- if not keys:
- keys = list()
- if not isinstance(keys, list):
- keys = [keys]
- self._keys = keys
- for key in filter(None, keys):
- leap_assert_type(key, OpenPGPKey)
-
- def __enter__(self):
- """
- Calls the unitary gpgwrapper initializer
-
- :return: A GPG wrapper with a unitary keyring.
- :rtype: gnupg.GPG
- """
- self._build_keyring()
- return self._gpg
-
- def __exit__(self, exc_type, exc_value, traceback):
- """
- Ensures the gpgwrapper is properly destroyed.
- """
- # TODO handle exceptions and log here
- self._destroy_keyring()
-
- def _build_keyring(self):
- """
- Create an empty GPG keyring and import C{keys} into it.
-
- :param keys: List of keys to add to the keyring.
- :type keys: list of OpenPGPKey
-
- :return: A GPG wrapper with a unitary keyring.
- :rtype: gnupg.GPG
- """
- privkeys = [key for key in self._keys if key and key.private is True]
- publkeys = [key for key in self._keys if key and key.private is False]
- # here we filter out public keys that have a correspondent
- # private key in the list because the private key_data by
- # itself is enough to also have the public key in the keyring,
- # and we want to count the keys afterwards.
-
- privaddrs = map(lambda privkey: privkey.address, privkeys)
- publkeys = filter(
- lambda pubkey: pubkey.address not in privaddrs, publkeys)
-
- listkeys = lambda: self._gpg.list_keys()
- listsecretkeys = lambda: self._gpg.list_keys(secret=True)
-
- self._gpg = GPGWrapper(gnupghome=tempfile.mkdtemp())
- leap_assert(len(listkeys()) is 0, 'Keyring not empty.')
-
- # import keys into the keyring:
- # concatenating ascii-armored keys, which is correctly
- # understood by the GPGWrapper.
-
- self._gpg.import_keys("".join(
- [x.key_data for x in publkeys + privkeys]))
-
- # assert the number of keys in the keyring
- leap_assert(
- len(listkeys()) == len(publkeys) + len(privkeys),
- 'Wrong number of public keys in keyring: %d, should be %d)' %
- (len(listkeys()), len(publkeys) + len(privkeys)))
- leap_assert(
- len(listsecretkeys()) == len(privkeys),
- 'Wrong number of private keys in keyring: %d, should be %d)' %
- (len(listsecretkeys()), len(privkeys)))
-
- def _destroy_keyring(self):
- """
- Securely erase a unitary keyring.
- """
- # TODO: implement some kind of wiping of data or a more
- # secure way that
- # does not write to disk.
-
- try:
- for secret in [True, False]:
- for key in self._gpg.list_keys(secret=secret):
- self._gpg.delete_keys(
- key['fingerprint'],
- secret=secret)
- leap_assert(len(self._gpg.list_keys()) is 0, 'Keyring not empty!')
-
- except:
- raise
-
- finally:
- leap_assert(self._gpg.gnupghome != os.path.expanduser('~/.gnupg'),
- "watch out! Tried to remove default gnupg home!")
- shutil.rmtree(self._gpg.gnupghome)
-
-
-#
-# API functions
-#
-
-@with_temporary_gpg
-def encrypt_asym(data, key, passphrase=None, sign=None):
- """
- Encrypt C{data} using public @{key} and sign with C{sign} key.
-
- :param data: The data to be encrypted.
- :type data: str
- :param pubkey: The key used to encrypt.
- :type pubkey: OpenPGPKey
- :param sign: The key used for signing.
- :type sign: OpenPGPKey
-
- :return: The encrypted data.
- :rtype: str
- """
- leap_assert_type(key, OpenPGPKey)
- leap_assert(key.private is False, 'Key is not public.')
- if sign is not None:
- leap_assert_type(sign, OpenPGPKey)
- leap_assert(sign.private is True)
-
- # Here we cannot assert for correctness of sig because the sig is in
- # the ciphertext.
- # result.ok - (bool) indicates if the operation succeeded
- # result.data - (bool) contains the result of the operation
-
- return lambda gpg: gpg.encrypt(
- data, key.fingerprint,
- sign=sign.key_id if sign else None,
- passphrase=passphrase, symmetric=False)
-
-
-@with_temporary_gpg
-def decrypt_asym(data, key, passphrase=None, verify=None):
- """
- Decrypt C{data} using private @{key} and verify with C{verify} key.
-
- :param data: The data to be decrypted.
- :type data: str
- :param privkey: The key used to decrypt.
- :type privkey: OpenPGPKey
- :param verify: The key used to verify a signature.
- :type verify: OpenPGPKey
-
- :return: The decrypted data.
- :rtype: str
-
- @raise InvalidSignature: Raised if unable to verify the signature with
- C{verify} key.
- """
- leap_assert(key.private is True, 'Key is not private.')
- if verify is not None:
- leap_assert_type(verify, OpenPGPKey)
- leap_assert(verify.private is False)
-
- return lambda gpg: gpg.decrypt(
- data, passphrase=passphrase)
-
-
-@with_temporary_gpg
-def is_encrypted(data):
- """
- Return whether C{data} was encrypted using OpenPGP.
-
- :param data: The data we want to know about.
- :type data: str
-
- :return: Whether C{data} was encrypted using this wrapper.
- :rtype: bool
- """
- return lambda gpg: gpg.is_encrypted(data)
-
-
-@with_temporary_gpg
-def is_encrypted_asym(data):
- """
- Return whether C{data} was asymmetrically encrypted using OpenPGP.
-
- :param data: The data we want to know about.
- :type data: str
-
- :return: Whether C{data} was encrypted using this wrapper.
- :rtype: bool
- """
- return lambda gpg: gpg.is_encrypted_asym(data)
-
-
-@with_temporary_gpg
-def sign(data, privkey):
- """
- Sign C{data} with C{privkey}.
-
- :param data: The data to be signed.
- :type data: str
-
- :param privkey: The private key to be used to sign.
- :type privkey: OpenPGPKey
-
- :return: The ascii-armored signed data.
- :rtype: str
- """
- leap_assert_type(privkey, OpenPGPKey)
- leap_assert(privkey.private is True)
-
- # result.fingerprint - contains the fingerprint of the key used to
- # sign.
- return lambda gpg: gpg.sign(data, keyid=privkey.key_id)
-
-
-@with_temporary_gpg
-def verify(data, key):
- """
- Verify signed C{data} with C{pubkey}.
-
- :param data: The data to be verified.
- :type data: str
-
- :param pubkey: The public key to be used on verification.
- :type pubkey: OpenPGPKey
-
- :return: The ascii-armored signed data.
- :rtype: str
- """
- leap_assert_type(key, OpenPGPKey)
- leap_assert(key.private is False)
-
- return lambda gpg: gpg.verify(data)
-
-
-#
-# Helper functions
-#
-
-
-def _build_key_from_gpg(address, key, key_data):
- """
- Build an OpenPGPKey for C{address} based on C{key} from
- local gpg storage.
-
- ASCII armored GPG key data has to be queried independently in this
- wrapper, so we receive it in C{key_data}.
-
- :param address: The address bound to the key.
- :type address: str
- :param key: Key obtained from GPG storage.
- :type key: dict
- :param key_data: Key data obtained from GPG storage.
- :type key_data: str
- :return: An instance of the key.
- :rtype: OpenPGPKey
- """
- return OpenPGPKey(
- address,
- key_id=key['keyid'],
- fingerprint=key['fingerprint'],
- key_data=key_data,
- private=True if key['type'] == 'sec' else False,
- length=key['length'],
- expiry_date=key['expires'],
- validation=None, # TODO: verify for validation.
- )
-
-
-#
-# The OpenPGP wrapper
-#
-
-class OpenPGPKey(EncryptionKey):
- """
- Base class for OpenPGP keys.
- """
-
-
-class OpenPGPScheme(EncryptionScheme):
- """
- A wrapper for OpenPGP keys.
- """
-
- def __init__(self, soledad):
- """
- Initialize the OpenPGP wrapper.
-
- :param soledad: A Soledad instance for key storage.
- :type soledad: leap.soledad.Soledad
- """
- EncryptionScheme.__init__(self, soledad)
-
- def gen_key(self, address):
- """
- Generate an OpenPGP keypair bound to C{address}.
-
- :param address: The address bound to the key.
- :type address: str
- :return: The key bound to C{address}.
- :rtype: OpenPGPKey
- @raise KeyAlreadyExists: If key already exists in local database.
- """
- # make sure the key does not already exist
- leap_assert(is_address(address), 'Not an user address: %s' % address)
- try:
- self.get_key(address)
- raise errors.KeyAlreadyExists(address)
- except errors.KeyNotFound:
- pass
-
- def _gen_key(gpg):
- params = gpg.gen_key_input(
- key_type='RSA',
- key_length=4096,
- name_real=address,
- name_email=address,
- name_comment='Generated by LEAP Key Manager.')
- gpg.gen_key(params)
- pubkeys = gpg.list_keys()
- # assert for new key characteristics
- leap_assert(
- len(pubkeys) is 1, # a unitary keyring!
- 'Keyring has wrong number of keys: %d.' % len(pubkeys))
- key = gpg.list_keys(secret=True).pop()
- leap_assert(
- len(key['uids']) is 1, # with just one uid!
- 'Wrong number of uids for key: %d.' % len(key['uids']))
- leap_assert(
- re.match('.*<%s>$' % address, key['uids'][0]) is not None,
- 'Key not correctly bound to address.')
- # insert both public and private keys in storage
- for secret in [True, False]:
- key = gpg.list_keys(secret=secret).pop()
- openpgp_key = _build_key_from_gpg(
- address, key,
- gpg.export_keys(key['fingerprint'], secret=secret))
- self.put_key(openpgp_key)
-
- with temporary_gpgwrapper() as gpg:
- # TODO: inspect result, or use decorator
- _gen_key(gpg)
-
- return self.get_key(address, private=True)
-
- def get_key(self, address, private=False):
- """
- Get key bound to C{address} from local storage.
-
- :param address: The address bound to the key.
- :type address: str
- :param private: Look for a private key instead of a public one?
- :type private: bool
-
- :return: The key bound to C{address}.
- :rtype: OpenPGPKey
- @raise KeyNotFound: If the key was not found on local storage.
- """
- leap_assert(is_address(address), 'Not an user address: %s' % address)
- doc = self._get_key_doc(address, private)
- if doc is None:
- raise errors.KeyNotFound(address)
- return build_key_from_dict(OpenPGPKey, address, doc.content)
-
- def put_ascii_key(self, key_data):
- """
- Put key contained in ascii-armored C{key_data} in local storage.
-
- :param key_data: The key data to be stored.
- :type key_data: str
- """
- leap_assert_type(key_data, str)
- # TODO: add more checks for correct key data.
- leap_assert(key_data is not None, 'Data does not represent a key.')
-
- def _put_ascii_key(gpg):
- gpg.import_keys(key_data)
- privkey = None
- pubkey = None
-
- try:
- privkey = gpg.list_keys(secret=True).pop()
- except IndexError:
- pass
- pubkey = gpg.list_keys(secret=False).pop() # unitary keyring
- # extract adress from first uid on key
- match = re.match('.*<([\w.-]+@[\w.-]+)>.*', pubkey['uids'].pop())
- leap_assert(match is not None, 'No user address in key data.')
- address = match.group(1)
- if privkey is not None:
- match = re.match(
- '.*<([\w.-]+@[\w.-]+)>.*', privkey['uids'].pop())
- leap_assert(match is not None, 'No user address in key data.')
- privaddress = match.group(1)
- leap_assert(
- address == privaddress,
- 'Addresses in pub and priv key differ.')
- leap_assert(
- pubkey['fingerprint'] == privkey['fingerprint'],
- 'Fingerprints for pub and priv key differ.')
- # insert private key in storage
- openpgp_privkey = _build_key_from_gpg(
- address, privkey,
- gpg.export_keys(privkey['fingerprint'], secret=True))
- self.put_key(openpgp_privkey)
- # insert public key in storage
- openpgp_pubkey = _build_key_from_gpg(
- address, pubkey,
- gpg.export_keys(pubkey['fingerprint'], secret=False))
- self.put_key(openpgp_pubkey)
-
- with temporary_gpgwrapper() as gpg:
- # TODO: inspect result, or use decorator
- _put_ascii_key(gpg)
-
- def put_key(self, key):
- """
- Put C{key} in local storage.
-
- :param key: The key to be stored.
- :type key: OpenPGPKey
- """
- doc = self._get_key_doc(key.address, private=key.private)
- if doc is None:
- self._soledad.create_doc_from_json(key.get_json())
- else:
- doc.set_json(key.get_json())
- self._soledad.put_doc(doc)
-
- def _get_key_doc(self, address, private=False):
- """
- Get the document with a key (public, by default) bound to C{address}.
-
- If C{private} is True, looks for a private key instead of a public.
-
- :param address: The address bound to the key.
- :type address: str
- :param private: Whether to look for a private key.
- :type private: bool
- :return: The document with the key or None if it does not exist.
- :rtype: leap.soledad.backends.leap_backend.LeapDocument
- """
- doclist = self._soledad.get_from_index(
- TAGS_ADDRESS_PRIVATE_INDEX,
- KEYMANAGER_KEY_TAG,
- address,
- '1' if private else '0')
- if len(doclist) is 0:
- return None
- leap_assert(
- len(doclist) is 1,
- 'Found more than one %s key for address!' %
- 'private' if private else 'public')
- return doclist.pop()
-
- def delete_key(self, key):
- """
- Remove C{key} from storage.
-
- :param key: The key to be removed.
- :type key: EncryptionKey
- """
- leap_assert(key.__class__ is OpenPGPKey, 'Wrong key type.')
- stored_key = self.get_key(key.address, private=key.private)
- if stored_key is None:
- raise errors.KeyNotFound(key)
- if stored_key.__dict__ != key.__dict__:
- raise errors.KeyAttributesDiffer(key)
- doc = self._get_key_doc(key.address, key.private)
- self._soledad.delete_doc(doc)