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authorkali <kali@leap.se>2013-01-23 07:02:58 +0900
committerkali <kali@leap.se>2013-01-23 07:02:58 +0900
commit8226d6032b6db0c15ff70e377f87f4acfdd21787 (patch)
tree95fcc3b400eee4297a73ac94db75bc5dfc56c4d0 /pkg/linux/resolv-update
parent06a1ef47e1719c3987006043fd1aae10e6da5c86 (diff)
working up/down resolv-conf script
Diffstat (limited to 'pkg/linux/resolv-update')
-rwxr-xr-xpkg/linux/resolv-update90
1 files changed, 90 insertions, 0 deletions
diff --git a/pkg/linux/resolv-update b/pkg/linux/resolv-update
new file mode 100755
index 00000000..a54802e3
--- /dev/null
+++ b/pkg/linux/resolv-update
@@ -0,0 +1,90 @@
+#!/bin/bash
+#
+# Parses options from openvpn to update resolv.conf
+#
+# The only way to enforce that a linux system will not leak DNS
+# queries is to replace /etc/resolv.conf with a file that only
+# has the DNS resolver specified by the VPN.
+#
+# That is what this script does. This is what resolvconf is for,
+# but sadly it does not always work.
+#
+# Example envs set from openvpn:
+# foreign_option_1='dhcp-option DNS 193.43.27.132'
+# foreign_option_2='dhcp-option DNS 193.43.27.133'
+# foreign_option_3='dhcp-option DOMAIN be.bnc.ch'
+#
+
+function up() {
+
+ comment=$(
+cat <<SETVAR
+#
+# This is a temporary resolv.conf set by the LEAP Client in order to
+# strictly enforce that DNS lookups are secured by the VPN.
+#
+# When the LEAP Client quits or the VPN connection it manages is dropped,
+# this file will be replace with the regularly scheduled /etc/resolv.conf
+#
+# If you want custom entries to appear in this file while LEAP is running,
+# put them in /etc/leap/resolv-head or /etc/leap/resolv-tail. These files
+# should only be writable by root.
+#
+
+SETVAR
+)
+
+ if [ -f /etc/leap/resolv-head ] ; then
+ custom_head=$(cat /etc/leap/resolv-head)
+ else
+ custom_head=""
+ fi
+
+ if [ -f /etc/leap/resolv-tail ] ; then
+ custom_tail=$(cat /etc/leap/resolv-tail)
+ else
+ custom_tail=""
+ fi
+
+ for optionname in ${!foreign_option_*} ; do
+ option="${!optionname}"
+ echo $option
+ part1=$(echo "$option" | cut -d " " -f 1)
+ if [ "$part1" == "dhcp-option" ] ; then
+ part2=$(echo "$option" | cut -d " " -f 2)
+ part3=$(echo "$option" | cut -d " " -f 3)
+ if [ "$part2" == "DNS" ] ; then
+ IF_DNS_NAMESERVERS="$IF_DNS_NAMESERVERS $part3"
+ fi
+ if [ "$part2" == "DOMAIN" ] ; then
+ IF_DNS_SEARCH="$IF_DNS_SEARCH $part3"
+ fi
+ fi
+ done
+ R=""
+ for SS in $IF_DNS_SEARCH ; do
+ R="${R}search $SS
+"
+ done
+ for NS in $IF_DNS_NAMESERVERS ; do
+ R="${R}nameserver $NS
+"
+ done
+ mv /etc/resolv.conf /etc/resolv.conf.bak
+ echo "$comment
+$custom_head
+$R
+$custom_tail" > /etc/resolv.conf
+}
+
+function down() {
+ if [ -f /etc/resolv.conf.bak ] ; then
+ unlink /etc/resolv.conf
+ mv /etc/resolv.conf.bak /etc/resolv.conf
+ fi
+}
+
+case $script_type in
+ up) up ;;
+ down) down ;;
+esac