Attachment 9117 Details for Bug 41005 – sanitizing.patch

[patch] sanitizing.patch

sanitizing.patch (text/plain), 4.50 KB, created by Janek Walkenhorst on 2017-08-14 18:11:14 CEST

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Creator: Janek Walkenhorst

Created: 2017-08-14 18:11:14 CEST

Size: 4.50 KB

patch

obsolete

>commit 324d10944c55d94dcfba78cd1831e14bc4fff543
>Author: Janek Walkenhorst <walkenhorst@univention.de>
>Date:   Mon Aug 14 16:44:31 2017 +0200
>
>    sanitizing
>
>diff --git a/services/univention-bind/bind.py b/services/univention-bind/bind.py
>index 8b86a0b..6e8bbe9 100755
>--- a/services/univention-bind/bind.py
>+++ b/services/univention-bind/bind.py
>@@ -45,6 +45,7 @@ import time
> import errno
> import signal
> import grp
>+import urllib
> 
> name = 'bind'
> description = 'Update BIND zones'
>@@ -98,9 +99,11 @@ def handler(dn, new, old):
> 			_remove_zone(old['zoneName'][0])
> 		if new.get('zoneName'):
> 			# Change
>-			# Create an empty file to trigger the postrun()
>-			zonefile = os.path.join(PROXY_CACHE_DIR, "%s.zone" % (new['zoneName'][0],))
>+			# Create a file to trigger the postrun()
>+			zone = new['zoneName'][0]
>+			zonefile = sanitized_path_join(PROXY_CACHE_DIR, "%s.zone" % (zone, ))
> 			proxy_cache = open(zonefile, 'w')
>+			proxy_cache.write(zone)
> 			proxy_cache.close()
> 			os.chmod(zonefile, 0o640)
> 			chgrp_bind(zonefile)
>@@ -125,7 +128,7 @@ def _new_zone(ucr, zonename, dn):
> 		os.mkdir(NAMED_CONF_DIR)
> 		os.chmod(NAMED_CONF_DIR, 0o755)
> 
>-	zonefile = os.path.join(NAMED_CONF_DIR, zonename)
>+	zonefile = sanitized_path_join(NAMED_CONF_DIR, zonename)
> 
> 	# Create empty file and restrict permission
> 	named_zone = open(zonefile, 'w')
>@@ -149,11 +152,11 @@ def _new_zone(ucr, zonename, dn):
> 	named_zone.close()
> 
> 	# Create proxy configuration file
>-	proxy_file = os.path.join(NAMED_CONF_DIR, zonename + '.proxy')
>+	proxy_file = sanitized_path_join(NAMED_CONF_DIR, zonename + '.proxy')
> 	proxy_zone = open(proxy_file, 'w')
> 	proxy_zone.write('zone "%s" {\n' % (zonename,))
> 	proxy_zone.write('\ttype slave;\n')
>-	proxy_zone.write('\tfile "%s.zone";\n' % (zonename,))
>+	proxy_zone.write('\tfile "%s.zone";\n' % (sanitize_filename(zonename),))
> 	proxy_zone.write('\tmasters port 7777 { 127.0.0.1; };\n')
> 	proxy_zone.write('};\n')
> 	proxy_zone.close()
>@@ -167,8 +170,8 @@ def _new_zone(ucr, zonename, dn):
> def _remove_zone(zonename):
> 	"""Handle removal of zone."""
> 	ud.debug(ud.LISTENER, ud.INFO, 'DNS: Removing zone %s' % (zonename,))
>-	zonefile = os.path.join(NAMED_CONF_DIR, zonename)
>-	cached_zonefile = os.path.join(NAMED_CACHE_DIR, zonename + '.zone')
>+	zonefile = sanitized_path_join(NAMED_CONF_DIR, zonename)
>+	cached_zonefile = sanitized_path_join(NAMED_CACHE_DIR, zonename + '.zone')
> 	# Remove zone file
> 	if os.path.exists(zonefile):
> 		os.unlink(zonefile)
>@@ -318,13 +321,18 @@ def postrun():
> 				__zone_created_or_removed = False
> 		elif dns_backend == 'ldap':
> 			for filename in os.listdir(PROXY_CACHE_DIR):
>-				os.remove(os.path.join(PROXY_CACHE_DIR, filename))
>+				filepath = os.path.join(PROXY_CACHE_DIR, filename)
>+				zone = open(filepath, 'rb').read()
>+				os.remove(filepath)
> 				if not os.path.exists(os.path.join(NAMED_CACHE_DIR, filename)):
> 					ud.debug(ud.LISTENER, ud.PROCESS, 'DNS: %s does not exist. Triggering a bind9 restart.' % (os.path.join(NAMED_CACHE_DIR, filename)))
> 					restart = True
> 				else:
>-					zone = filename.replace(".zone", "")
>-					zones.append(zone)
>+					_, ext = os.path.splitext(filename)
>+					if ext == '.zone':
>+						zones.append(zone)
>+					else:
>+						ud.debug(ud.LISTENER, ud.WARN, 'DNS: strange file in PROXY_CACHE_DIR: %r' % (filename, ))
> 			if zones:
> 				ud.debug(ud.LISTENER, ud.INFO, 'DNS: Zones: %s' % (zones,))
> 		elif dns_backend == 'none':
>@@ -341,3 +349,16 @@ def postrun():
> 		_kill_children(pids)
> 	finally:
> 		listener.unsetuid()
>+
>+def sanitize_filename(bytestring):
>+	escaped = urllib.quote(bytestring, safe='')
>+	if escaped.startswith('.'): # always encode leading dot because '.' and '..' are special names
>+		escaped = '%20' + escaped[1:]
>+	return escaped
>+
>+def sanitized_path_join(directory, unsafe_filename):
>+	filename = sanitize_filename(unsafe_filename)
>+	assert '/' not in filename
>+	assert '\0' not in filename
>+	assert filename not in ('.', '..', )
>+	return os.path.join(directory, filename)
>diff --git a/services/univention-bind/debian/univention-bind.postinst b/services/univention-bind/debian/univention-bind.postinst
>index 93e1583..87fe36c 100644
>--- a/services/univention-bind/debian/univention-bind.postinst
>+++ b/services/univention-bind/debian/univention-bind.postinst
>@@ -82,6 +82,10 @@ if [ "$1" = "configure" ]; then
> 		systemctl --system daemon-reload
> 	}
> 	if [ -n "$2" ]; then
>+		if dpkg --compare-versions "$2" lt 10.0.2-6 # update to sanitized filenames
>+		then
>+			univention-directory-listener-ctrl resync bind
>+		fi
> 		invoke-rc.d bind9 crestart
> 	else
> 		invoke-rc.d bind9 start

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