Add GnuPG encryption support for addresses with delimiters

If a user registers their key for address alice@example.com but receives a
message sent to alice+something@example.com, this message should be encrypted
as well.

- Implement delimiter support for GnuPG encryption.

- Add E2E test case for a clear text message delivered to an address with
delimiter.

- Fix minor bug: wrong configuration parameter was retrieved when logging
information about enc_domain_keymap being active.

gpg-mailgate.py

@@ -59,9 +59,15 @@ def gpg_encrypt( raw_message, recipients ):
 	for fingerprint in keys:
 		keys[fingerprint] = sanitize_case_sense(keys[fingerprint])
 
+	# This list will be filled with pairs (M, N), where M is the destination
+	# address we're going to deliver the message to and N is the identity we're
+	# going to encrypt it for.
 	gpg_to = list()
+
 	ungpg_to = list()
 
+	enc_keymap_only = conf.config_item_equals('default', 'enc_keymap_only', 'yes')
+
 	for to in recipients:
 
 		# Check if recipient is in keymap
@@ -75,16 +81,23 @@ def gpg_encrypt( raw_message, recipients ):
 				LOG.info("Key '%s' in encrypt keymap not found in keyring for email address '%s'." % (conf.get_item('enc_keymap', to), to))
 
 		# Check if key in keychain is present
-		if to in keys.values() and not conf.config_item_equals('default', 'enc_keymap_only', 'yes'):
-			gpg_to.append( (to, to) )
-			continue
+		if not enc_keymap_only:
+			if to in keys.values():
+				gpg_to.append( (to, to) )
+				continue
+
+            # If this is an address with a delimiter (i.e. "foo+bar@example.com"),
+            # then strip whatever is found after the delimiter and try this address.
+			(newto, topic) = text.parse_delimiter(to)
+			if newto in keys.values():
+				gpg_to.append((to, newto))
 
 		# Check if there is a default key for the domain
 		splitted_to = to.split('@')
 		if len(splitted_to) > 1:
 			domain = splitted_to[1]
 			if conf.config_item_set('enc_domain_keymap', domain):
-				LOG.info("Encrypt domain keymap has key '%s'" % conf.get_item('enc_dec_keymap', domain) )
+				LOG.info("Encrypt domain keymap has key '%s'" % conf.get_item('enc_domain_keymap', domain) )
 				# Check we've got a matching key!
 				if conf.get_item('enc_domain_keymap', domain) in keys:
 					LOG.info("Using default domain key for recipient '%s'" % to)

test/e2e.ini

@@ -30,7 +30,7 @@ certs: test/certs
 
 [tests]
 # Number of "test-*" sections in this file, describing test cases.
-cases: 7
+cases: 8
 e2e_log: test/logs/e2e.log
 e2e_log_format: %(asctime)s %(pathname)s:%(lineno)d %(levelname)s [%(funcName)s] %(message)s
 e2e_log_datefmt: %Y-%m-%d %H:%M:%S
@@ -78,3 +78,9 @@ descr: Clear text message to a user with an RSA key and PGP/MIME enabled in conf
 to: evan@disposlab
 in: test/msgin/clear2rsa2.msg
 out: -----BEGIN PGP MESSAGE-----
+
+[case-8]
+descr: Clear text message to address with delimiter and a user with an Ed25519 key.
+to: bob@disposlab
+in: test/msgin/clear2ed-delim.msg
+out: -----BEGIN PGP MESSAGE-----

test/msgin/clear2ed-delim.msg

@@ -0,0 +1,5 @@
+From: Dave <dave@localhost>
+To: Bob <bob+foobar@localhost>
+Subject: Test
+
+Body of the message.