S/MIME Email registration

register-handler.py

@@ -0,0 +1,99 @@
+#!/usr/bin/python
+
+from ConfigParser import RawConfigParser
+import email, os, smtplib, sys, traceback, markdown, syslog
+from M2Crypto import BIO, Rand, SMIME, X509
+
+from email.mime.text import MIMEText
+from email.mime.multipart import MIMEMultipart
+
+# Read configuration from /etc/gpg-mailgate.conf
+_cfg = RawConfigParser()
+_cfg.read('/etc/gpg-mailgate.conf')
+cfg = dict()
+for sect in _cfg.sections():
+	cfg[sect] = dict()
+	for (name, value) in _cfg.items(sect):
+		cfg[sect][name] = value
+
+def log(msg):
+	if cfg.has_key('logging') and cfg['logging'].has_key('file'):
+		if cfg['logging']['file'] == "syslog":
+			syslog.syslog(syslog.LOG_INFO | syslog.LOG_MAIL, msg)
+		else:
+			logfile = open(cfg['logging']['file'], 'a')
+			logfile.write(msg + "\n")
+			logfile.close()
+
+CERT_PATH = cfg['smime']['cert_path']+"/"
+
+def send_msg( message, from_addr, recipients = None ):
+    relay = ("127.0.0.1", 10028)
+    smtp = smtplib.SMTP(relay[0], relay[1])
+    smtp.sendmail( from_addr, recipients, message.as_string() )
+
+if __name__ == "__main__":
+#	try:
+		# Read e-mail from stdin
+		raw = sys.stdin.read()
+		register_msg = email.message_from_string( raw )
+		from_addr = email.utils.parseaddr(register_msg['From'])[1]
+
+		sign_part = None
+		for msg_part in register_msg.walk():
+			if msg_part.get_content_type().lower() == "application/pkcs7-signature":
+				sign_part = msg_part
+				break
+
+		if sign_part == None:
+			log("Unable to find PKCS7 signature in registration email")
+
+			failure_msg = file( cfg['smime']['mail_templates'] + "/registrationError.md").read()
+			msg = MIMEMultipart("alternative")
+			msg["From"] = cfg['smime']['register_email']
+			msg["To"] = from_addr
+			msg["Subject"] = "S/MIME registration failed"
+
+			msg.attach(MIMEText(failure_msg, 'plain'))
+			msg.attach(MIMEText(markdown.markdown(failure_msg), 'html'))
+
+			send_msg(msg, cfg['smime']['register_email'], [from_addr])
+			sys.exit(0)
+
+		raw_sig = sign_part.get_payload().replace("\n","")
+		# re-wrap signature so that it fits base64 standards
+		cooked_sig = '\n'.join(raw_sig[pos:pos+76] for pos in xrange(0, len(raw_sig), 76))
+		# now, wrap the signature in a PKCS7 block
+		sig = """
+-----BEGIN PKCS7-----
+%s
+-----END PKCS7-----
+		""" % cooked_sig
+
+		# and load it into an SMIME p7 object through the BIO I/O buffer:
+		buf = BIO.MemoryBuffer(sig)
+		p7 = SMIME.load_pkcs7_bio(buf)
+
+		sk = X509.X509_Stack()
+		signers = p7.get0_signers(sk)
+		signing_cert = signers[0]
+
+		signing_cert.save(os.path.join(CERT_PATH, from_addr))
+
+		# format in user-specific data
+		success_msg = file(cfg['smime']['mail_templates']+"/registrationSuccess.md").read()
+		success_msg = success_msg.replace("[:FROMADDRESS:]",from_addr)
+
+		msg = MIMEMultipart("alternative")
+		msg["From"] = cfg['smime']['register_email']
+		msg["To"] = from_addr
+		msg["Subject"] = "S/MIME key registration succeeded"
+
+		msg.attach(MIMEText(success_msg, 'plain'))
+		msg.attach(MIMEText(markdown.markdown(success_msg), 'html'))
+
+		log("Registration succeeded")
+		send_msg(msg, cfg['smime']['register_email'], [from_addr])
+#	except:
+#		log("Registration exception")
+#		sys.exit(0)