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[openpgp] Be more resistant against invalid keys

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This commit is contained in:
lovetox
2022-04-18 14:04:43 +02:00
parent be9afe8719
commit 572301fe89
3 changed files with 98 additions and 58 deletions
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27
openpgp/backend/gpgme.py
View File

@@ -14,6 +14,7 @@
# You should have received a copy of the GNU General Public License
# along with OpenPGP Gajim Plugin. If not, see <http://www.gnu.org/licenses/>.
from typing import Optional
import logging
@@ -22,6 +23,7 @@ from nbxmpp.protocol import JID
import gpg
from gpg.results import ImportResult
from openpgp.backend.util import parse_uid
from openpgp.modules.util import DecryptionFailed
log = logging.getLogger('gajim.p.openpgp.gpgme')
@@ -39,10 +41,17 @@ class KeyringItem:
except Exception:
return False
def _get_uid(self):
def is_valid(self, jid: JID) -> bool:
if not self.is_xmpp_key:
return False
return jid == self.jid
def _get_uid(self) -> Optional[str]:
for uid in self._key.uids:
if uid.uid.startswith('xmpp:'):
return uid.uid
try:
return parse_uid(uid.uid)
except Exception:
pass
@property
def fingerprint(self):
@@ -56,7 +65,7 @@ class KeyringItem:
@property
def jid(self):
if self._uid is not None:
return JID.from_string(self._uid[5:])
return JID.from_string(self._uid)
def __hash__(self):
return hash(self.fingerprint)
@@ -118,6 +127,7 @@ class GPGME:
keyring_item = KeyringItem(key)
if not keyring_item.is_xmpp_key:
log.warning('Key not suited for xmpp: %s', key.fpr)
self.delete_key(keyring_item.fingerprint)
continue
keys.append(keyring_item)
@@ -191,10 +201,17 @@ class GPGME:
fingerprint = result.imports[0].fpr
key = self.get_key(fingerprint)
item = KeyringItem(key)
if not item.is_valid(jid):
log.warning('Invalid key found')
log.warning(key)
self.delete_key(item.fingerprint)
return
return KeyringItem(key)
return item
def delete_key(self, fingerprint):
log.info('Delete Key: %s', fingerprint)
key = self.get_key(fingerprint)
with gpg.Context(**self._context_args) as context:
context.op_delete(key, True)

116
openpgp/backend/pygpg.py
View File

@@ -14,21 +14,68 @@
# You should have received a copy of the GNU General Public License
# along with OpenPGP Gajim Plugin. If not, see <http://www.gnu.org/licenses/>.
import os
from typing import Optional
import logging
from collections import namedtuple
import gnupg
from nbxmpp.protocol import JID
from openpgp.backend.util import parse_uid
from openpgp.modules.util import DecryptionFailed
log = logging.getLogger('gajim.p.openpgp.pygnupg')
if log.getEffectiveLevel() == logging.DEBUG:
log = logging.getLogger('gnupg')
log.addHandler(logging.StreamHandler())
log.setLevel(logging.DEBUG)
KeyringItem = namedtuple('KeyringItem', 'jid keyid fingerprint')
class KeyringItem:
def __init__(self, key):
self._key = key
self._uid = self._get_uid()
@property
def is_xmpp_key(self) -> bool:
try:
return self.jid is not None
except Exception:
return False
def is_valid(self, jid: JID) -> bool:
if not self.is_xmpp_key:
return False
return jid == self.jid
@property
def keyid(self) -> str:
return self._key['keyid']
def _get_uid(self) -> Optional[str]:
for uid in self._key['uids']:
try:
return parse_uid(uid)
except Exception:
pass
@property
def fingerprint(self):
return self._key['fingerprint']
@property
def uid(self):
if self._uid is not None:
return self._uid
@property
def jid(self):
if self._uid is not None:
return JID.from_string(self._uid)
def __hash__(self):
return hash(self.fingerprint)
class PythonGnuPG(gnupg.GPG):
@@ -93,22 +140,15 @@ class PythonGnuPG(gnupg.GPG):
result = super().list_keys(secret=secret)
keys = []
for key in result:
item = self._make_keyring_item(key)
if item is None:
item = KeyringItem(key)
if not item.is_xmpp_key:
log.warning('Invalid key found, deleting key')
log.warning(key)
self.delete_key(item.fingerprint)
continue
keys.append(self._make_keyring_item(key))
keys.append(item)
return keys
@staticmethod
def _make_keyring_item(key):
userid = key['uids'][0]
if not userid.startswith('xmpp:'):
log.warning('Incorrect userid: %s found for key, '
'key will be ignored', userid)
return
jid = userid[5:]
return KeyringItem(jid, key['keyid'], key['fingerprint'])
def import_key(self, data, jid):
log.info('Import key from %s', jid)
result = super().import_keys(data)
@@ -117,45 +157,15 @@ class PythonGnuPG(gnupg.GPG):
log.error(result)
return
if not self.validate_key(data, str(jid)):
return None
key = self.get_key(result.results[0]['fingerprint'])
return self._make_keyring_item(key[0])
item = KeyringItem(key[0])
if not item.is_valid(jid):
log.warning('Invalid key found, deleting key')
log.warning(key)
self.delete_key(item.fingerprint)
return
def validate_key(self, public_key, jid):
import tempfile
temppath = os.path.join(tempfile.gettempdir(), 'temp_pubkey')
with open(temppath, 'wb') as tempfile:
tempfile.write(public_key)
result = self.scan_keys(temppath)
if result:
key_found = False
for uid in result.uids:
if uid.startswith('xmpp:'):
if uid[5:] == jid:
key_found = True
else:
log.warning('Found wrong userid in key: %s != %s',
uid[5:], jid)
log.debug(result)
os.remove(temppath)
return False
if not key_found:
log.warning('No valid userid found in key')
log.debug(result)
os.remove(temppath)
return False
log.info('Key validation succesful')
os.remove(temppath)
return True
log.warning('Invalid key data: %s')
log.debug(result)
os.remove(temppath)
return False
return item
def get_own_key_details(self):
result = super().list_keys(secret=True)

13
openpgp/backend/util.py Normal file
View File

@@ -0,0 +1,13 @@
from __future__ import annotations
def parse_uid(uid: str, compat=False) -> str:
if uid.startswith('xmpp:'):
return uid[5:]
# Compat with uids of form "Name <xmpp:my@jid.com>"
if compat and '<xmpp:' in uid and uid.endswith('>'):
return uid[:-1].split('<xmpp:', maxsplit=1)[1]
raise ValueError('Uknown UID format: %s' % uid)