dnsmasq: add and enable DNS rebind protections

SVN-Revision: 22222

package/dnsmasq/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=dnsmasq
 PKG_VERSION:=2.55
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=http://thekelleys.org.uk/dnsmasq

package/dnsmasq/files/dhcp.conf

@@ -1,8 +1,11 @@
 config dnsmasq
 	option domainneeded	1
 	option boguspriv	1
-	option filterwin2k	'0'  #enable for dial on demand
+	option filterwin2k	0  # enable for dial on demand
 	option localise_queries	1
+	option rebind_protection 1  # disable if upstream must serve RFC1918 addresses
+	option rebind_localhost 0  # enable for RBL checking and similar services
+	#list rebind_domain example.lan  # whitelist RFC1918 responses for domains
 	option local	'/lan/'
 	option domain	'lan'
 	option expandhosts	1

package/dnsmasq/files/dnsmasq.init

@@ -99,6 +99,29 @@ dnsmasq() {
 
 	config_get hostsfile "$cfg" dhcphostsfile
 	[ -e "$hostsfile" ] && append args "--dhcp-hostsfile=$hostsfile"
+
+	local rebind
+	config_get_bool rebind "$cfg" rebind_protection 1
+	[ $rebind -gt 0 ] && {
+		logger -t dnsmasq \
+			"DNS rebinding protection is active," \
+			"will discard upstream RFC1918 responses!"
+		append args "--stop-dns-rebind"
+
+		local rebind_localhost
+		config_get_bool rebind_localhost "$cfg" rebind_localhost 0
+		[ $rebind_localhost -gt 0 ] && {
+			logger -t dnsmasq "Allowing 127.0.0.0/8 responses"
+			append args "--rebind-localhost-ok"
+		}
+
+		append_rebind_domain() {
+			logger -t dnsmasq "Allowing RFC1918 responses for domain $1"
+			append args "--rebind-domain-ok=$1"
+		}
+
+		config_list_foreach "$cfg" rebind_domain append_rebind_domain
+	}
 }
 
 dhcp_subscrid_add() {