remail/gpg: Store sender information

For contact points (open list) it's required to collect the sender
information, email address and if available the GPG key which is contained
in the signature.

Set the encryption method info and if the mail is signed store the GPG key.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

remail/gpg.py

@@ -7,6 +7,7 @@
 from remail.mail import msg_set_payload, msg_set_header
 from remail.mail import msg_get_payload_as_string
 from remail.mail import msg_from_string, msg_set_gpg_payload
+from remail.mail import get_raw_email_addr
 
 import hashlib
 import string
@@ -20,6 +21,40 @@ class RemailGPGException(Exception):
 class RemailGPGKeyException(Exception):
     pass
 
+class gpg_sender_info(object):
+    def __init__(self, gpg, result):
+        self.gpg = gpg
+        self.results = [result]
+
+    def append(self, result):
+        self.results.append(result)
+
+    def get_info(self):
+        info = ''
+        for result in self.results:
+            if result.signature_id:
+                info += 'Username:     %s\n' %result.username
+                info += 'Key Id:       %s\n' %result.key_id
+                info += 'Signature Id: %s\n' %result.signature_id
+                info += 'Fingerprint:  %s\n' %result.fingerprint
+
+        if info == '':
+            info = 'No further information available\n'
+        return 'GPG\n' + info
+
+    def get_file(self):
+        for result in self.results:
+            if result.fingerprint:
+                try:
+                    fname = get_raw_email_addr(result.username)
+                    fname += '.gpg'
+                    # Return the ASCII armored public key
+                    key = self.gpg.export_keys([result.fingerprint])
+                    return fname, key, 'plain', 'text'
+                except:
+                    pass
+        return None, None, None, None
+
 class gpg_crypt(object):
     def __init__(self, gpgcfg, account, checkkey=True):
         self.config = gpgcfg
@@ -125,7 +160,13 @@ class gpg_crypt(object):
         msg_set_gpg_payload(msg, encpl, account.addr)
         return msg
 
-    def gpg_decrypt_plain(self, msg):
+    def set_sender_info(self, sinfo, result):
+        if sinfo.info:
+            sinfo.info.update(result)
+        else:
+            sinfo.info = gpg_sender_info(self.gpg, result)
+
+    def gpg_decrypt_plain(self, msg, sinfo):
         '''
         Try to decrypt inline plain/text
 
@@ -138,6 +179,8 @@ class gpg_crypt(object):
             msg_set_payload(msg, msg_from_string(str(plain)))
             if plain.signature_id:
                 msg_set_header(msg, 'Signature-Id', plain.username)
+            self.set_sender_info(sinfo, plain)
+
         elif plain.status != 'no data was provided':
             # Check for an empty return path which is a good indicator
             # for a mail server message.
@@ -146,7 +189,7 @@ class gpg_crypt(object):
                 raise RemailGPGException('Decryption failed: %s' % plain.status)
         return msg
 
-    def gpg_decrypt_enveloped(self, msg):
+    def gpg_decrypt_enveloped(self, msg, sinfo):
         '''
         Try to decrypt an enveloped mail
         '''
@@ -171,6 +214,8 @@ class gpg_crypt(object):
         if plain.signature_id:
             msg_set_header(msg, 'Signature-Id', plain.username)
 
+        self.set_sender_info(sinfo, plain)
+
         pl = msg_from_string(str(plain))
         msg_set_payload(msg, pl)
         return msg
@@ -183,10 +228,10 @@ class gpg_crypt(object):
         ct = msg.get_content_type()
 
         if ct == 'text/plain':
-            return self.gpg_decrypt_plain(msgout)
+            return self.gpg_decrypt_plain(msgout, sinfo)
 
         elif ct == 'multipart/encrypted':
-            return self.gpg_decrypt_enveloped(msgout)
+            return self.gpg_decrypt_enveloped(msgout, sinfo)
 
         # There might be inline PGP with no mentioning in the content type
         if not msg.is_multipart():
@@ -195,7 +240,7 @@ class gpg_crypt(object):
         payloads = msgout.get_payload()
         payldecr = []
         for pl in payloads:
-            pl = self.decrypt(pl)
+            pl = self.decrypt(pl, sinfo)
             payldecr.append(pl)
         msgout.set_payload(payldecr)
         return msgout