PB-2205: using re.fullmatch() instead if re.match()

Using fullmatch() instead of match() only makes the service safer.
This way, even if the regex is not anchored, map.geo.admin.ch.evil.com
bypass trick will still be detected by the fullmatch and blocked.
Otherwise the regex needs to be anchored.

Author: hansmannj

app/helpers/url.py

@@ -32,7 +32,7 @@ def validate_url(url):
         logger.error('Invalid URL, could not determine the hostname, url=%s', url)
         abort(400, 'Invalid URL, could not determine the hostname')
 
-    if not re.match(ALLOWED_DOMAINS_PATTERN, result.hostname):
+    if not re.fullmatch(ALLOWED_DOMAINS_PATTERN, result.hostname):
         logger.error('URL domain not allowed: %s', result.hostname)
         abort(400, 'URL domain not allowed')