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freebsd/sbin/dhclient/dhclient-script
Brooks Davis f1bacaa501 Fix rev 1.12.
/tmp may not be writeable yet when dhclient is first run via
/etc/rc.d/netif so using it may not work.  Also, writing to a
predictable file in /tmp as root is a really bad idea since a malicious
user may be able to win a race and insert a symlink which will allow
them to cause any file to be overwritten.  To solve these problems,
create the tempory file in /var/run which will exist this early and is
writable only by root.

Security:	Local risk if users can cause dhclient to run on demand
		(such as by unplugging and replugging the network cable).
2006-01-26 21:05:39 +00:00

296 lines
7.2 KiB
Bash

#!/bin/sh
#
# $OpenBSD: dhclient-script,v 1.6 2004/05/06 18:22:41 claudio Exp $
# $FreeBSD$
#
# Copyright (c) 2003 Kenneth R Westerback <krw@openbsd.org>
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#
#
ARP=/usr/sbin/arp
AWK=/usr/bin/awk
HOSTNAME=/bin/hostname
NETSTAT=/usr/bin/netstat
LOCALHOST=127.0.0.1
if [ -x /usr/bin/logger ]; then
LOGGER="/usr/bin/logger -s -p user.notice -t dhclient"
else
LOGGER=echo
fi
#
# Helper functions that implement common actions.
#
check_hostname() {
current_hostname=`$HOSTNAME`
if [ -z "$current_hostname" ]; then
$LOGGER "New Hostname ($interface): $new_host_name"
$HOSTNAME $new_host_name
elif [ "$current_hostname" = "$old_host_name" -a \
"$new_host_name" != "$old_host_name" ]; then
$LOGGER "New Hostname ($interface): $new_host_name"
$HOSTNAME $new_host_name
fi
}
arp_flush() {
arp -an -i $interface | \
sed -n -e 's/^.*(\(.*\)) at .*$/arp -d \1/p' | \
sh >/dev/null 2>&1
}
delete_old_address() {
eval "ifconfig $interface inet -alias $old_ip_address $medium"
}
add_new_address() {
eval "ifconfig $interface \
inet $new_ip_address \
netmask $new_subnet_mask \
broadcast $new_broadcast_address \
$medium"
$LOGGER "New IP Address ($interface): $new_ip_address"
$LOGGER "New Subnet Mask ($interface): $new_subnet_mask"
$LOGGER "New Broadcast Address ($interface): $new_broadcast_address"
$LOGGER "New Routers ($interface): $new_routers"
}
delete_old_alias() {
if [ -n "$alias_ip_address" ]; then
ifconfig $interface inet -alias $alias_ip_address > /dev/null 2>&1
#route delete $alias_ip_address $LOCALHOST > /dev/null 2>&1
fi
}
add_new_alias() {
if [ -n "$alias_ip_address" ]; then
ifconfig $interface inet alias $alias_ip_address netmask \
$alias_subnet_mask
#route add $alias_ip_address $LOCALHOST
fi
}
delete_old_routes() {
#route delete "$old_ip_address" $LOCALHOST >/dev/null 2>&1
for router in $old_routers; do
if [ $if_defaultroute = x -o $if_defaultroute = $interface ]; then
route delete default $route >/dev/null 2>&1
fi
done
if [ -n "$old_static_routes" ]; then
set $old_static_routes
while [ $# -gt 1 ]; do
route delete "$1" "$2"
shift; shift
done
fi
arp_flush
}
add_new_routes() {
#route add $new_ip_address $LOCALHOST >/dev/null 2>&1
for router in $new_routers; do
if [ "$new_ip_address" = "$router" ]; then
route add default -iface $router >/dev/null 2>&1
else
route add default $router >/dev/null 2>&1
fi
# 2nd and subsequent default routers error out, so explicitly
# stop processing the list after the first one.
break
done
if [ -n "$new_static_routes" ]; then
$LOGGER "New Static Routes ($interface): $new_static_routes"
set $new_static_routes
while [ $# -gt 1 ]; do
route add $1 $2
shift; shift
done
fi
}
add_new_resolv_conf() {
# XXX Old code did not create/update resolv.conf unless both
# $new_domain_name and $new_domain_name_servers were provided. PR
# #3135 reported some ISP's only provide $new_domain_name_servers and
# thus broke the script. This code creates the resolv.conf if either
# are provided.
local tmpres=/var/run/resolv.conf.${interface}
rm -f $tmpres
if [ -n "$new_domain_name" ]; then
echo "search $new_domain_name" >>$tmpres
fi
if [ -n "$new_domain_name_servers" ]; then
for nameserver in $new_domain_name_servers; do
echo "nameserver $nameserver" >>$tmpres
done
fi
if [ -f $tmpres ]; then
if [ -f /etc/resolv.conf.tail ]; then
cat /etc/resolv.conf.tail >>$tmpres
fi
# When resolv.conf is not changed actually, we don't
# need to update it.
# If /usr is not mounted yet, we cannot use cmp, then
# the following test fails. In such case, we simply
# ignore an error and do update resolv.conf.
if cmp -s $tmpres /etc/resolv.conf; then
rm -f $tmpres
return 0
fi 2>/dev/null
# In case (e.g. during OpenBSD installs) /etc/resolv.conf
# is a symbolic link, take care to preserve the link and write
# the new data in the correct location.
if [ -f /etc/resolv.conf ]; then
cat /etc/resolv.conf > /etc/resolv.conf.save
fi
cat $tmpres > /etc/resolv.conf
rm -f $tmpres
# Try to ensure correct ownership and permissions.
chown -RL root:wheel /etc/resolv.conf
chmod -RL 644 /etc/resolv.conf
return 0
fi
return 1
}
# Must be used on exit. Invokes the local dhcp client exit hooks, if any.
exit_with_hooks() {
exit_status=$1
if [ -f /etc/dhclient-exit-hooks ]; then
. /etc/dhclient-exit-hooks
fi
# probably should do something with exit status of the local script
exit $exit_status
}
#
# Start of active code.
#
# Invoke the local dhcp client enter hooks, if they exist.
if [ -f /etc/dhclient-enter-hooks ]; then
exit_status=0
. /etc/dhclient-enter-hooks
# allow the local script to abort processing of this state
# local script must set exit_status variable to nonzero.
if [ $exit_status -ne 0 ]; then
exit $exit_status
fi
fi
if [ -x $NETSTAT ]; then
if_defaultroute=`$NETSTAT -rnf inet | $AWK '{if ($1=="default") printf $6}'`
else
if_defaultroute="x"
fi
case $reason in
MEDIUM)
eval "ifconfig $interface $medium"
eval "ifconfig $interface inet -alias 0.0.0.0 $medium" >/dev/null 2>&1
sleep 1
;;
PREINIT)
delete_old_alias
ifconfig $interface inet 0.0.0.0 netmask 0.0.0.0 broadcast 255.255.255.255 up
;;
ARPCHECK|ARPSEND)
;;
BOUND|RENEW|REBIND|REBOOT)
check_hostname
if [ -n "$old_ip_address" ]; then
if [ "$old_ip_address" != "$alias_ip_address" ]; then
delete_old_alias
fi
if [ "$old_ip_address" != "$new_ip_address" ]; then
delete_old_address
delete_old_routes
fi
fi
if [ "$reason" = BOUND ] || \
[ "$reason" = REBOOT ] || \
[ -z "$old_ip_address" ] || \
[ "$old_ip_address" != "$new_ip_address" ]; then
add_new_address
add_new_routes
fi
if [ "$new_ip_address" != "$alias_ip_address" ]; then
add_new_alias
fi
add_new_resolv_conf
;;
EXPIRE|FAIL)
delete_old_alias
if [ -n "$old_ip_address" ]; then
delete_old_address
delete_old_routes
fi
if [ -x $ARP ]; then
$ARP -d -a -i $interface
fi
# XXX Why add alias we just deleted above?
add_new_alias
if [ -f /etc/resolv.conf.save ]; then
cat /etc/resolv.conf.save > /etc/resolv.conf
fi
;;
TIMEOUT)
delete_old_alias
add_new_address
sleep 1
if [ -n "$new_routers" ]; then
$LOGGER "New Routers ($interface): $new_routers"
set "$new_routers"
if ping -q -c 1 -t 1 "$1"; then
if [ "$new_ip_address" != "$alias_ip_address" ]; then
add_new_alias
fi
add_new_routes
if add_new_resolv_conf; then
exit_with_hooks 0
fi
fi
fi
eval "ifconfig $interface inet -alias $new_ip_address $medium"
delete_old_routes
exit_with_hooks 1
;;
esac
exit_with_hooks 0