Add CertBot Acme-DNS auth-hook

files/certbot/auth-hooks/acme-dns.py

@@ -0,0 +1,155 @@
+#!/usr/bin/env python3
+import json
+import os
+import requests
+import sys
+
+### EDIT THESE: Configuration values ###
+
+# URL to acme-dns instance
+ACMEDNS_URL = "https://acme-challenge.waren.io"
+# Path for acme-dns credential storage
+STORAGE_PATH = "/etc/letsencrypt/acmedns.json"
+# Whitelist for address ranges to allow the updates from
+# Example: ALLOW_FROM = ["192.168.10.0/24", "::1/128"]
+ALLOW_FROM = []
+# Force re-registration. Overwrites the already existing acme-dns accounts.
+FORCE_REGISTER = False
+
+###   DO NOT EDIT BELOW THIS POINT   ###
+###         HERE BE DRAGONS          ###
+
+DOMAIN = os.environ["CERTBOT_DOMAIN"]
+if DOMAIN.startswith("*."):
+    DOMAIN = DOMAIN[2:]
+VALIDATION_DOMAIN = "_acme-challenge."+DOMAIN
+VALIDATION_TOKEN = os.environ["CERTBOT_VALIDATION"]
+
+
+class AcmeDnsClient(object):
+    """
+    Handles the communication with ACME-DNS API
+    """
+
+    def __init__(self, acmedns_url):
+        self.acmedns_url = acmedns_url
+
+    def register_account(self, allowfrom):
+        """Registers a new ACME-DNS account"""
+
+        if allowfrom:
+            # Include whitelisted networks to the registration call
+            reg_data = {"allowfrom": allowfrom}
+            res = requests.post(self.acmedns_url+"/register",
+                                data=json.dumps(reg_data))
+        else:
+            res = requests.post(self.acmedns_url+"/register")
+        if res.status_code == 201:
+            # The request was successful
+            return res.json()
+        else:
+            # Encountered an error
+            msg = ("Encountered an error while trying to register a new acme-dns "
+                   "account. HTTP status {}, Response body: {}")
+            print(msg.format(res.status_code, res.text))
+            sys.exit(1)
+
+    def update_txt_record(self, account, txt):
+        """Updates the TXT challenge record to ACME-DNS subdomain."""
+        update = {"subdomain": account['subdomain'], "txt": txt}
+        headers = {"X-Api-User": account['username'],
+                   "X-Api-Key": account['password'],
+                   "Content-Type": "application/json"}
+        res = requests.post(self.acmedns_url+"/update",
+                            headers=headers,
+                            data=json.dumps(update))
+        if res.status_code == 200:
+            # Successful update
+            return
+        else:
+            msg = ("Encountered an error while trying to update TXT record in "
+                   "acme-dns. \n"
+                   "------- Request headers:\n{}\n"
+                   "------- Request body:\n{}\n"
+                   "------- Response HTTP status: {}\n"
+                   "------- Response body: {}")
+            s_headers = json.dumps(headers, indent=2, sort_keys=True)
+            s_update = json.dumps(update, indent=2, sort_keys=True)
+            s_body = json.dumps(res.json(), indent=2, sort_keys=True)
+            print(msg.format(s_headers, s_update, res.status_code, s_body))
+            sys.exit(1)
+
+class Storage(object):
+    def __init__(self, storagepath):
+        self.storagepath = storagepath
+        self._data = self.load()
+
+    def load(self):
+        """Reads the storage content from the disk to a dict structure"""
+        data = dict()
+        filedata = ""
+        try:
+            with open(self.storagepath, 'r') as fh:
+                filedata = fh.read()
+        except IOError as e:
+            if os.path.isfile(self.storagepath):
+                # Only error out if file exists, but cannot be read
+                print("ERROR: Storage file exists but cannot be read")
+                sys.exit(1)
+        try:
+            data = json.loads(filedata)
+        except ValueError:
+            if len(filedata) > 0:
+                # Storage file is corrupted
+                print("ERROR: Storage JSON is corrupted")
+                sys.exit(1)
+        return data
+
+    def save(self):
+        """Saves the storage content to disk"""
+        serialized = json.dumps(self._data)
+        try:
+            with os.fdopen(os.open(self.storagepath,
+                                   os.O_WRONLY | os.O_CREAT, 0o600), 'w') as fh:
+                fh.truncate()
+                fh.write(serialized)
+        except IOError as e:
+            print("ERROR: Could not write storage file.")
+            sys.exit(1)
+
+    def put(self, key, value):
+        """Puts the configuration value to storage and sanitize it"""
+        # If wildcard domain, remove the wildcard part as this will use the
+        # same validation record name as the base domain
+        if key.startswith("*."):
+            key = key[2:]
+        self._data[key] = value
+
+    def fetch(self, key):
+        """Gets configuration value from storage"""
+        try:
+            return self._data[key]
+        except KeyError:
+            return None
+
+if __name__ == "__main__":
+    # Init
+    client = AcmeDnsClient(ACMEDNS_URL)
+    storage = Storage(STORAGE_PATH)
+
+    # Check if an account already exists in storage
+    account = storage.fetch(DOMAIN)
+    if FORCE_REGISTER or not account:
+        # Create and save the new account
+        account = client.register_account(ALLOW_FROM)
+        storage.put(DOMAIN, account)
+        storage.save()
+
+        # Display the notification for the user to update the main zone
+        msg = "Please add the following CNAME record to your main DNS zone:\n{}"
+        cname = "{} CNAME {}.".format(VALIDATION_DOMAIN, account["fulldomain"])
+        print(msg.format(cname))
+
+    # Update the TXT record in acme-dns instance
+    client.update_txt_record(account, VALIDATION_TOKEN)
+