refactoring ACME protocol code

This patch breaks up the ACME protocol code into functions for account
registration, key/certificate file handling, and helpers for ACME
protocol communication.

acertmgr.py

@@ -98,9 +98,12 @@ def cert_get(domains, settings):
 		key = key_fd.read()
 		key_fd.close()
 		cr = acertmgr_ssl.cert_request(domains.split(), key)
-		crt = acertmgr_ssl.get_crt_from_csr(acc_file, cr, domains.split(), challenge_dir, settings['authority'])
+		print("Reading account key...")
+		acc_key = acertmgr_ssl.read_key(acc_file)
+		acertmgr_ssl.register_account(acc_key, settings['authority'])
+		crt = acertmgr_ssl.get_crt_from_csr(acc_key, cr, domains.split(), challenge_dir, settings['authority'])
 		with open(crt_file, "w") as crt_fd:
-			crt_fd.write(crt)
+			crt_fd.write(acertmgr_ssl.cert_to_pem(crt))
 
 		#  if resulting certificate is valid: store in final location
 		if cert_isValid(crt_file, 60):

acertmgr_ssl.py

@@ -50,32 +50,30 @@ def cert_request(names, key_data):
 	#return crypto.dump_certificate_request(crypto.FILETYPE_PEM, req)
 	return req
 
-
-# @brief helper function base64 encode for jose spec
-# @param b the string to encode
-# @return the encoded string
-def base64_enc(b):
-	return base64.urlsafe_b64encode(b).decode('utf8').replace("=", "")
-
-# @brief function to fetch certificate using ACME
-# @param account_key_file the path to the account key
-# @param csr the certificate signing request in pyopenssl format
-# @param domains list of domains in the certificate, first is CN
-# @param acme_dir directory for ACME challanges
-# @param CA which signing CA to use
+# @brief convert certificate to PEM format
+# @param cert certificate object in pyopenssl format
 # @return the certificate in PEM format
-# @note algorithm and parts of the code are from acme-tiny
-def get_crt_from_csr(account_key_file, csr, domains, acme_dir, CA):
-	print("Reading account key...")
-	with open(account_key_file) as f:
-		account_key_data = f.read()
-	account_key = crypto.load_privatekey(crypto.FILETYPE_PEM, account_key_data)
+def cert_to_pem(cert):
+	return crypto.dump_certificate(crypto.FILETYPE_PEM, cert).decode('utf8')
+
+# @brief read a key from file
+# @param path path to key file
+# @return the key in pyopenssl format
+def read_key(path):
+	with open(path) as f:
+		key_data = f.read()
+	return crypto.load_privatekey(crypto.FILETYPE_PEM, key_data)
+
+# @brief create the header information for ACME communication
+# @param key the account key
+# @return the header for ACME
+def acme_header(key):
 	proc = subprocess.Popen(['openssl', 'rsa', '-modulus', '-noout', '-text'],
 		stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-	out, err = proc.communicate(account_key_data.encode('utf8'))
+	out, err = proc.communicate(crypto.dump_privatekey(crypto.FILETYPE_PEM, key))
 	if proc.returncode != 0:
 		raise IOError("OpenSSL Error: {0}".format(err))
-	pub_exp, pub_hex = re.search(
+	pub_exp, pub_mod = re.search(
 		r"publicExponent: [0-9]+ \(0x([0-9A-F]+)\).+Modulus=([0-9A-F]+)",
 		out.decode('utf8'), re.DOTALL).groups()
 	pub_exp = "0{0}".format(pub_exp) if len(pub_exp) % 2 else pub_exp
@@ -84,46 +82,78 @@ def get_crt_from_csr(account_key_file, csr, domains, acme_dir, CA):
 		"jwk": {
 			"e": base64_enc(binascii.unhexlify(pub_exp.encode("utf-8"))),
 			"kty": "RSA",
-			"n": base64_enc(binascii.unhexlify(pub_hex.encode("utf-8"))),
+			"n": base64_enc(binascii.unhexlify(pub_mod.encode("utf-8"))),
 		},
 	}
-	accountkey_json = json.dumps(header['jwk'], sort_keys=True, separators=(',', ':'))
-	thumbprint = base64_enc(hashlib.sha256(accountkey_json.encode('utf8')).digest())
+	return header
 
-	# helper function make signed requests
-	def _send_signed_request(url, payload):
-		payload64 = base64_enc(json.dumps(payload).encode('utf8'))
-		protected = copy.deepcopy(header)
-		protected["nonce"] = urlopen(CA + "/directory").headers['Replay-Nonce']
-		protected64 = base64_enc(json.dumps(protected).encode('utf8'))
-		out = crypto.sign(account_key, '.'.join([protected64, payload64]), 'sha256')
-		data = json.dumps({
-			"header": header, "protected": protected64,
-			"payload": payload64, "signature": base64_enc(out),
-		})
-		try:
-			resp = urlopen(url, data.encode('utf8'))
-			return resp.getcode(), resp.read()
-		except IOError as e:
-			return getattr(e, "code", None), getattr(e, "read", e.__str__)()
-
-	code, result = _send_signed_request(CA + "/acme/new-reg", {
+# @brief register an account over ACME
+# @param account_key the account key to register
+# @param CA the certificate authority to register with
+# @return True if new account was registered, False otherwise
+def register_account(account_key, CA):
+	header = acme_header(account_key)
+	code, result = send_signed(account_key, CA, CA + "/acme/new-reg", header, {
 		"resource": "new-reg",
 		"agreement": "https://letsencrypt.org/documents/LE-SA-v1.0.1-July-27-2015.pdf",
 	})
 	if code == 201:
 		print("Registered!")
+		return True
 	elif code == 409:
 		print("Already registered!")
+		return False
 	else:
 		raise ValueError("Error registering: {0} {1}".format(code, result))
 
+# @brief helper function to base64 encode for JSON objects
+# @param b the string to encode
+# @return the encoded string
+def base64_enc(b):
+	return base64.urlsafe_b64encode(b).decode('utf8').replace("=", "")
+
+
+# @brief helper function to make signed requests
+# @param CA the certificate authority
+# @param url the request URL
+# @param header the message header
+# @param payload the message
+# @return tuple of return code and request answer
+def send_signed(account_key, CA, url, header, payload):
+	payload64 = base64_enc(json.dumps(payload).encode('utf8'))
+	protected = copy.deepcopy(header)
+	protected["nonce"] = urlopen(CA + "/directory").headers['Replay-Nonce']
+	protected64 = base64_enc(json.dumps(protected).encode('utf8'))
+	out = crypto.sign(account_key, '.'.join([protected64, payload64]), 'sha256')
+	data = json.dumps({
+		"header": header, "protected": protected64,
+		"payload": payload64, "signature": base64_enc(out),
+	})
+	try:
+		resp = urlopen(url, data.encode('utf8'))
+		return resp.getcode(), resp.read()
+	except IOError as e:
+		return getattr(e, "code", None), getattr(e, "read", e.__str__)()
+
+# @brief function to fetch certificate using ACME
+# @param account_key the account key in pyopenssl format
+# @param csr the certificate signing request in pyopenssl format
+# @param domains list of domains in the certificate, first is CN
+# @param acme_dir directory for ACME challanges
+# @param CA which signing CA to use
+# @return the certificate in pyopenssl format
+# @note algorithm and parts of the code are from acme-tiny
+def get_crt_from_csr(account_key, csr, domains, acme_dir, CA):
+	header = acme_header(account_key)
+	accountkey_json = json.dumps(header['jwk'], sort_keys=True, separators=(',', ':'))
+	account_thumbprint = base64_enc(hashlib.sha256(accountkey_json.encode('utf8')).digest())
+
 	# verify each domain
 	for domain in domains:
 		print("Verifying {0}...".format(domain))
 
 		# get new challenge
-		code, result = _send_signed_request(CA + "/acme/new-authz", {
+		code, result = send_signed(account_key, CA, CA + "/acme/new-authz", header, {
 			"resource": "new-authz",
 			"identifier": {"type": "dns", "value": domain},
 		})
@@ -133,7 +163,7 @@ def get_crt_from_csr(account_key_file, csr, domains, acme_dir, CA):
 		# make the challenge file
 		challenge = [c for c in json.loads(result.decode('utf8'))['challenges'] if c['type'] == "http-01"][0]
 		token = re.sub(r"[^A-Za-z0-9_\-]", "_", challenge['token'])
-		keyauthorization = "{0}.{1}".format(token, thumbprint)
+		keyauthorization = "{0}.{1}".format(token, account_thumbprint)
 		wellknown_path = os.path.join(acme_dir, token)
 		with open(wellknown_path, "w") as wellknown_file:
 			wellknown_file.write(keyauthorization)
@@ -150,7 +180,7 @@ def get_crt_from_csr(account_key_file, csr, domains, acme_dir, CA):
 				wellknown_path, wellknown_url))
 
 		# notify challenge are met
-		code, result = _send_signed_request(challenge['uri'], {
+		code, result = send_signed(account_key, CA, challenge['uri'], header, {
 			"resource": "challenge",
 			"keyAuthorization": keyauthorization,
 		})
@@ -178,7 +208,7 @@ def get_crt_from_csr(account_key_file, csr, domains, acme_dir, CA):
 	# get the new certificate
 	print("Signing certificate...")
 	csr_der = crypto.dump_certificate_request(crypto.FILETYPE_ASN1, csr)
-	code, result = _send_signed_request(CA + "/acme/new-cert", {
+	code, result = send_signed(account_key, CA, CA + "/acme/new-cert", header, {
 		"resource": "new-cert",
 		"csr": base64_enc(csr_der),
 	})
@@ -188,5 +218,5 @@ def get_crt_from_csr(account_key_file, csr, domains, acme_dir, CA):
 	# return signed certificate!
 	print("Certificate signed!")
 	cert = crypto.load_certificate(crypto.FILETYPE_ASN1, result)
-	return crypto.dump_certificate(crypto.FILETYPE_PEM, cert).decode('utf8')
+	return cert