diff options
| -rwxr-xr-x | roles/common/files/etc/network/if-up.d/ipsec | 44 | ||||
| -rwxr-xr-x | roles/common/files/usr/local/sbin/update-firewall.sh | 29 | ||||
| -rw-r--r-- | roles/common/tasks/ipsec.yml | 4 |
3 files changed, 50 insertions, 27 deletions
diff --git a/roles/common/files/etc/network/if-up.d/ipsec b/roles/common/files/etc/network/if-up.d/ipsec index e21d6ea..98bf42c 100755 --- a/roles/common/files/etc/network/if-up.d/ipsec +++ b/roles/common/files/etc/network/if-up.d/ipsec @@ -1,44 +1,56 @@ #!/bin/sh # # A post-up/down hook to automatically create/delete a 'sec' VLAN # device, and a dedicated, host-scoped, IP for IPSec (v4 only). # # Copyright 2013 Guilhem Moulin <guilhem@fripost.org> # # Licensed under the GNU GPL version 3 or higher. # set -ue PATH=/usr/sbin:/usr/bin:/sbin:/bin -if=sec0 -ip=172.16.0.1/32 +ifsec=sec0 +ipsec=172.16.0.1/32 + +# /!\ This mark much match that in /usr/local/sbin/update-firewall.sh. +secmark=0xA99 # Ignore the loopback interface and non inet4 families. [ "$IFACE" != lo -a "$ADDRFAM" = inet ] || exit 0 # Only the device with the default, globally-scoped route, is of # interest here. [ "$( /bin/ip -4 route show to default scope global \ | sed -nr '/^default via \S+ dev (\S+).*/ {s//\1/p;q}' )" \ = \ "$IFACE" ] || exit 0 case "$MODE" in - start) # Don't create $if if it's already there - /bin/ip -o link show | grep -qE "^[0-9]+:\s+$if" && exit 0 - - # Create a new VLAN $IFACE on physical device $if. This is - # required otherwise charon thinks the left peer is that - # host-scoped, non-routable IP. - /bin/ip link add link "$IFACE" name "$if" type vlan id 2713 - /bin/ip address add "$ip" dev "$if" scope host - /bin/ip link set dev "$if" up + start) # Don't create $ifsec if it's already there + if ! /bin/ip -o link show | grep -qE "^[0-9]+:\s+$ifsec"; then + # Create a new VLAN $IFACE on physical device $ifsec. This is + # required otherwise charon thinks the left peer is that + # host-scoped, non-routable IP. + /bin/ip link add link "$IFACE" name "$ifsec" type vlan id 2713 + /bin/ip address add "$ipsec" dev "$ifsec" scope host + /bin/ip link set dev "$ifsec" up + fi + + # If a packet retained its mark that far, it means it has + # been SNAT'ed from $ipsec, and didn't have a xfrm + # association. Hence we nullroute it to avoid leaking data. + /bin/ip rule add fwmark "$secmark" table 666 priority 666 || true + /bin/ip route add prohibit default table 666 || true ;; - stop) # Don't create $if if it's no there - /bin/ip -o link show | grep -qE "^[0-9]+:\s+$if" || exit 0 - - # Deactivate the VLAN - /bin/ip link set dev "$if" down + stop) if /bin/ip -o link show | grep -qE "^[0-9]+:\s+$ifsec"; then + # Deactivate the VLAN + /bin/ip link set dev "$ifsec" down + fi + + # Delete the 'prohibit' rule + /bin/ip rule del fwmark "$secmark" table 666 priority 666 || true + /bin/ip route flush table 666 ;; esac diff --git a/roles/common/files/usr/local/sbin/update-firewall.sh b/roles/common/files/usr/local/sbin/update-firewall.sh index a8123f9..0907ffc 100755 --- a/roles/common/files/usr/local/sbin/update-firewall.sh +++ b/roles/common/files/usr/local/sbin/update-firewall.sh @@ -130,45 +130,47 @@ ipt-revert() { rm -f "${rss[$f]}" done exit 1 } run() { # Build and apply the firewall for IPv4/6. local f="$1" local ipt=/sbin/$(inet46 $f iptables ip6tables) tables[$f]=filter # The default interface associated with this address. local if=$( /bin/ip -$f route show to default scope global \ | sed -nr '/^default via \S+ dev (\S+).*/ {s//\1/p;q}' ) # The virtual interface reserved for IPSec. local ifsec=$( /bin/ip -o -$f link show \ | sed -nr "/^[0-9]+:\s+(sec[0-9]+)@$if:\s.*/ {s//\1/p;q}" ) # The (host-scoped) IP reserved for IPSec. - local ipsec= + local ipsec= secmark if [ -n "$ifsec" -a $f = 4 ]; then tables[$f]='mangle nat filter' ipsec=$( /bin/ip -$f address show dev "$ifsec" scope host \ | sed -nr '/^\s+inet\s(\S+).*/ {s//\1/p;q}' ) + # /!\ This mark much match that in /etc/network/if-up.d/ipsec. + secmark=0xA99 fi # Store the old (current) ruleset local old=$(mktemp -t current-rules.v$f.XXXXXX) \ new=$(mktemp -t new-rules.v$f.XXXXXX) for table in ${tables[$f]}; do $ipt-save -ct $table done > "$old" rss[$f]="$old" local fail2ban=0 # XXX: As of Wheezy, fail2ban is IPv4 only. See # https://github.com/fail2ban/fail2ban/issues/39 for the current # state of the art. if [ "$f" = 4 ] && which /usr/bin/fail2ban-server >/dev/null; then fail2ban=1 fi # The usual chains in filter, along with the desired default policies. ipt-chains filter INPUT:DROP FORWARD:DROP OUTPUT:DROP @@ -234,41 +236,41 @@ run() { fi # DROP INVALID packets immediately. iptables -A INPUT -m state --state INVALID -j DROP iptables -A OUTPUT -m state --state INVALID -j DROP # DROP bogus TCP packets. iptables -A INPUT -p tcp -m tcp --tcp-flags FIN,SYN FIN,SYN -j DROP iptables -A INPUT -p tcp -m tcp --tcp-flags SYN,RST SYN,RST -j DROP # Allow all input/output to/from the loopback interface. local localhost=$(inet46 $f '127.0.0.1/32' '::1/128') iptables -A INPUT -i lo -s "$localhost" -d "$localhost" -j ACCEPT iptables -A OUTPUT -o lo -s "$localhost" -d "$localhost" -j ACCEPT if [ -n "$ipsec" ]; then # ACCEPT any, *IPSec* traffic destinating to the non-routable # $ipsec. Also ACCEPT all traffic originating from $ipsec, as # it is MASQUERADE'd. iptables -A INPUT -d "$ipsec" -i $if -m policy --dir in --pol ipsec -j ACCEPT - iptables -A OUTPUT -s "$ipsec" -o $if -j ACCEPT + iptables -A OUTPUT -m mark --mark "$secmark" -o $if -j ACCEPT fi # Prepare fail2ban. We make fail2ban insert its rules in a # dedicated chain, so that it doesn't mess up the existing rules. [ $fail2ban -eq 1 ] && iptables -A INPUT -i $if -j fail2ban if [ "$f" = 4 ]; then # Allow only ICMP of type 0, 3 and 8. The rate-limiting is done # directly by the kernel (net.ipv4.icmp_ratelimit and # net.ipv4.icmp_ratemask runtime options). See icmp(7). local t for t in 'echo-reply' 'destination-unreachable' 'echo-request'; do iptables -A INPUT -i $if -p icmp -m icmp --icmp-type $t -j ACCEPT iptables -A OUTPUT -o $if -p icmp -m icmp --icmp-type $t -j ACCEPT done elif [ $f = 6 ]; then iptables -A INPUT -i $ip -p icmpv6 -j ACCEPT fi @@ -305,56 +307,65 @@ run() { in|inout) iptNew="-A INPUT -i"; iptEst="-A OUTPUT -o";; out) iptNew="-A OUTPUT -o"; iptEst="-A INPUT -i";; *) fatal "Error: Unknown direction: '$dir'." esac iptables $iptNew $if -p $proto $optsNew -m state --state $stNew -j ACCEPT iptables $iptEst $if -p $proto $optsEst -m state --state $stEst -j ACCEPT done ######################################################################## commit if [ -n "$ipsec" ]; then # DNAT the IPSec paquets to $ipsec after decapsulation, and SNAT # them before encapsulation. We need to do the NAT'ing before # packets enter the IPSec stack because they are signed # afterwards, and NAT'ing would mess up the signature. ipt-chains mangle PREROUTING:ACCEPT INPUT:ACCEPT \ FORWARD:DROP \ OUTPUT:ACCEPT POSTROUTING:ACCEPT + # Packets which destination is $ipsec *must* be associated with # an IPSec policy. iptables -A INPUT -d "$ipsec" -i $if -m policy --dir in --pol none -j DROP + + # Packets originating from our (non-routable) $ipsec are marked; + # if there is no xfrm lookup (i.e., no matching IPSec + # association), the packet will retain its mark and be null + # routed later on. Otherwise, the packet is re-queued unmarked. + iptables -A OUTPUT -o $if -j MARK --set-mark 0x0 + iptables -A OUTPUT -s "$ipsec" -o $if -m policy --dir out --pol none \ + -j MARK --set-mark $secmark commit ipt-chains nat PREROUTING:ACCEPT INPUT:ACCEPT \ OUTPUT:ACCEPT POSTROUTING:ACCEPT - # DNAT all marked packets after decapsulation. Packets - # originating from our IPSec are SNAT'ed (MASQUERADE). XXX: - # xfrm lookup occurs *after* NAT POSTROUTING, so sadly we can't - # DROP packets not matching an IPSec policy. However, any reply - # not going through IPSec would be DROPped (thanks to the rule - # in mangle:INPUT above); this is the best we can do for now. + + # DNAT all marked packets after decapsulation. iptables -A PREROUTING \! -d "$ipsec" -i $if \ -m policy --dir in --pol ipsec -j DNAT --to "${ipsec%/*}" - iptables -A POSTROUTING -s "$ipsec" -o $if -j MASQUERADE + + # Packets originating from our IPSec are SNAT'ed (MASQUERADE). + # (And null-routed later on unless there is an xfrm + # association.) + iptables -A POSTROUTING -m mark --mark $secmark -o $if -j MASQUERADE commit fi ######################################################################## local rv1=0 rv2=0 persistent=/etc/iptables/rules.v$f local oldz=$(mktemp -t current-rules.v$f.XXXXXX) # Reset the counters. They are not useful for comparing and/or # storing persistent ruleset. (We don't use sed -i because we want # to restore the counters when reverting.) sed -r -e '/^:/ s/\[[0-9]+:[0-9]+\]$/[0:0]/' \ -e 's/^\[[0-9]+:[0-9]+\]\s+//' \ "$old" > "$oldz" /usr/bin/uniq "$new" | /bin/ip netns exec $netns $ipt-restore || ipt-revert for table in ${tables[$f]}; do /bin/ip netns exec $netns $ipt-save -t $table diff --git a/roles/common/tasks/ipsec.yml b/roles/common/tasks/ipsec.yml index 3d7a1dd..4c0a946 100644 --- a/roles/common/tasks/ipsec.yml +++ b/roles/common/tasks/ipsec.yml @@ -26,30 +26,30 @@ template: src=etc/ipsec.secrets.j2 dest=/etc/ipsec.secrets owner=root group=root mode=0600 notify: - Restart IPSec - name: Configure IPSec template: src=etc/ipsec.conf.j2 dest=/etc/ipsec.conf owner=root group=root mode=0644 notify: - Restart IPSec - name: Auto-create a dedicated interface for IPSec copy: src=etc/network/if-up.d/ipsec dest=/etc/network/if-up.d/ipsec owner=root group=root mode=0755 + notify: + - Reload networking # XXX: As of 1.3.1 ansible doesn't accept relative src. # See https://github.com/ansible/ansible/issues/4459 - name: Auto-deactivate the dedicated interface for IPSec file: #src=../if-up.d/ipsec src=/etc/network/if-up.d/ipsec dest=/etc/network/if-down.d/ipsec owner=root group=root state=link - notify: - - Reload networking |