[pgp] Move all Gajim PGP code into plugin

pgp/backend/python_gnupg.py

@@ -0,0 +1,153 @@
+# Copyright (C) 2019 Philipp Hörist <philipp AT hoerist.com>
+# Copyright (C) 2003-2014 Yann Leboulanger <asterix AT lagaule.org>
+# Copyright (C) 2005 Alex Mauer <hawke AT hawkesnest.net>
+# Copyright (C) 2005-2006 Nikos Kouremenos <kourem AT gmail.com>
+# Copyright (C) 2007 Stephan Erb <steve-e AT h3c.de>
+# Copyright (C) 2008 Jean-Marie Traissard <jim AT lapin.org>
+#                    Jonathan Schleifer <js-gajim AT webkeks.org>
+#
+# This file is part of PGP Gajim Plugin.
+#
+# PGP Gajim Plugin 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; version 3 only.
+#
+# PGP Gajim Plugin 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 PGP Gajim Plugin. If not, see <http://www.gnu.org/licenses/>.
+
+import os
+import logging
+from functools import lru_cache
+
+import gnupg
+
+from gajim.common.helpers import Singleton
+
+from pgp.exceptions import SignError
+
+
+logger = logging.getLogger('gajim.p.pgplegacy')
+if logger.getEffectiveLevel() == logging.DEBUG:
+    logger = logging.getLogger('gnupg')
+    logger.addHandler(logging.StreamHandler())
+    logger.setLevel(logging.DEBUG)
+
+
+class PGP(gnupg.GPG, metaclass=Singleton):
+    def __init__(self, binary, encoding=None):
+        super().__init__(gpgbinary=binary,
+                         use_agent=True)
+
+        if encoding is not None:
+            self.encoding = encoding
+        self.decode_errors = 'replace'
+
+    def encrypt(self, payload, recipients, always_trust=False):
+        if not always_trust:
+            # check that we'll be able to encrypt
+            result = self.get_key(recipients[0])
+            for key in result:
+                if key['trust'] not in ('f', 'u'):
+                    return '', 'NOT_TRUSTED ' + key['keyid'][-8:]
+
+        result = super().encrypt(
+            payload.encode('utf8'),
+            recipients,
+            always_trust=always_trust)
+
+        if result.ok:
+            error = ''
+        else:
+            error = result.status
+
+        return self._strip_header_footer(str(result)), error
+
+    def decrypt(self, payload):
+        data = self._add_header_footer(payload, 'MESSAGE')
+        result = super().decrypt(data.encode('utf8'))
+
+        return result.data.decode('utf8')
+
+    @lru_cache(maxsize=8)
+    def sign(self, payload, key_id):
+        if payload is None:
+            payload = ''
+        result = super().sign(payload.encode('utf8'),
+                              keyid=key_id,
+                              detach=True)
+
+        if result.fingerprint:
+            return self._strip_header_footer(str(result))
+        raise SignError(result.status)
+
+    def verify(self, payload, signed):
+        # Hash algorithm is not transfered in the signed
+        # presence stanza so try all algorithms.
+        # Text name for hash algorithms from RFC 4880 - section 9.4
+
+        if payload is None:
+            payload = ''
+
+        hash_algorithms = ['SHA512', 'SHA384', 'SHA256',
+                           'SHA224', 'SHA1', 'RIPEMD160']
+        for algo in hash_algorithms:
+            data = os.linesep.join(
+                ['-----BEGIN PGP SIGNED MESSAGE-----',
+                 'Hash: ' + algo,
+                 '',
+                 payload,
+                 self._add_header_footer(signed, 'SIGNATURE')]
+                )
+            result = super().verify(data.encode('utf8'))
+            if result.valid:
+                return result.key_id
+
+    def get_key(self, key_id):
+        return super().list_keys(keys=[key_id])
+
+    def get_keys(self, secret=False):
+        keys = {}
+        result = super().list_keys(secret=secret)
+
+        for key in result:
+            # Take first not empty uid
+            keys[key['keyid'][8:]] = [uid for uid in key['uids'] if uid][0]
+        return keys
+
+    @staticmethod
+    def _strip_header_footer(data):
+        """
+        Remove header and footer from data
+        """
+        if not data:
+            return ''
+        lines = data.splitlines()
+        while lines[0] != '':
+            lines.remove(lines[0])
+        while lines[0] == '':
+            lines.remove(lines[0])
+        i = 0
+        for line in lines:
+            if line:
+                if line[0] == '-':
+                    break
+            i = i+1
+        line = '\n'.join(lines[0:i])
+        return line
+
+    @staticmethod
+    def _add_header_footer(data, type_):
+        """
+        Add header and footer from data
+        """
+        out = "-----BEGIN PGP %s-----" % type_ + os.linesep
+        out = out + "Version: PGP" + os.linesep
+        out = out + os.linesep
+        out = out + data + os.linesep
+        out = out + "-----END PGP %s-----" % type_ + os.linesep
+        return out