diff --git a/roles/vpn/tasks/client_configs.yml b/roles/vpn/tasks/client_configs.yml index ea1621a..5c32ded 100644 --- a/roles/vpn/tasks/client_configs.yml +++ b/roles/vpn/tasks/client_configs.yml @@ -9,7 +9,6 @@ - name: Set facts for mobileconfigs set_fact: - proxy_enabled: false PayloadContentCA: "{{ lookup('file' , 'configs/{{ IP_subject_alt_name }}/pki/cacert.pem')|b64encode }}" - name: Build the mobileconfigs diff --git a/roles/vpn/templates/mobileconfig.j2 b/roles/vpn/templates/mobileconfig.j2 index ce51ea5..b8013df 100644 --- a/roles/vpn/templates/mobileconfig.j2 +++ b/roles/vpn/templates/mobileconfig.j2 @@ -124,24 +124,12 @@ Proxies HTTPEnable -{% if proxy_enabled is defined and proxy_enabled == true %} - 1 - HTTPPort - 8118 - HTTPProxy - {{ local_service_ip }} - {% else %} 0 -{% endif %} HTTPSEnable 0 UserDefinedName -{% if proxy_enabled is defined and proxy_enabled == true %} - Algo VPN {{ IP_subject_alt_name }} IKEv2 with proxy - {% else %} Algo VPN {{ IP_subject_alt_name }} IKEv2 -{% endif %} VPNType IKEv2 @@ -187,17 +175,9 @@ PayloadDisplayName -{% if proxy_enabled is defined and proxy_enabled == true %} - {{ IP_subject_alt_name }} IKEv2 with proxy - {% else %} {{ IP_subject_alt_name }} IKEv2 -{% endif %} PayloadIdentifier -{% if proxy_enabled is defined and proxy_enabled == true %} - donut.local.{{ 600000 | random | to_uuid | upper }} - {% else %} donut.local.{{ 500000 | random | to_uuid | upper }} -{% endif %} PayloadRemovalDisallowed PayloadType diff --git a/roles/vpn/templates/rules.v4.j2 b/roles/vpn/templates/rules.v4.j2 index e040b18..c51568a 100644 --- a/roles/vpn/templates/rules.v4.j2 +++ b/roles/vpn/templates/rules.v4.j2 @@ -1,43 +1,95 @@ +#### The mangle table +# This table allows us to modify packet headers +# Packets enter this table first +# *mangle + :PREROUTING ACCEPT [0:0] :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] + {% if max_mss is defined %} +# MSS is the TCP Max Segment Size +# Setting the 'max_mss' Ansible variable can solve some issues related to packet fragmentation +# This appears to be necessary on (at least) Google Cloud, +# however, some routers also require a change to this parameter +# See also: +# - https://github.com/trailofbits/algo/issues/216 +# - https://github.com/trailofbits/algo/issues?utf8=%E2%9C%93&q=is%3Aissue%20mtu +# - https://serverfault.com/questions/601143/ssh-not-working-over-ipsec-tunnel-strongswan -A FORWARD -s {{ vpn_network }} -p tcp -m tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss {{ max_mss }} {% endif %} + COMMIT + + +#### The nat table +# This table enables Network Address Translation +# (This is technically a type of packet mangling) +# *nat + :PREROUTING ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] + +# Allow traffic from the VPN network to the outside world, and replies -A POSTROUTING -s {{ vpn_network }} -m policy --pol none --dir out -j MASQUERADE + COMMIT + + +#### The filter table +# The default ipfilter table +# *filter + +# By default, drop packets that are destined for this server :INPUT DROP [0:0] +# By default, drop packets that request to be forwarded by this server :FORWARD DROP [0:0] +# By default, accept any packets originating from this server :OUTPUT ACCEPT [0:0] + +# Accept packets destined for localhost -A INPUT -i lo -j ACCEPT +# Accept any packet from an open TCP connection -A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT +# Accept packets using the encapsulation protocol -A INPUT -p esp -j ACCEPT -A INPUT -p ah -j ACCEPT # rate limit ICMP traffic per source -A INPUT -p icmp --icmp-type echo-request -m hashlimit --hashlimit-upto 5/s --hashlimit-mode srcip --hashlimit-srcmask 32 --hashlimit-name icmp-echo-drop -j ACCEPT +# Accept IPSEC traffic to ports 500 (IPSEC) and 4500 (MOBIKE aka IKE + NAT traversal) -A INPUT -p udp -m multiport --dports 500,4500 -j ACCEPT +# Allow new traffic to port 22 (SSH) -A INPUT -p tcp --dport 22 -m conntrack --ctstate NEW -j ACCEPT +# Allow any traffic from the VPN -A INPUT -p ipencap -m policy --dir in --pol ipsec --proto esp -j ACCEPT + # TODO: # The IP of the resolver should be bound to a DUMMY interface. # DUMMY interfaces are the proper way to install IPs without assigning them any # particular virtual (tun,tap,...) or physical (ethernet) interface. + +# Accept DNS traffic to the local DNS resolver -A INPUT -d {{ local_service_ip }} -p udp --dport 53 -j ACCEPT --A INPUT -d {{ local_service_ip }} -p tcp -m multiport --dport 8080,8118 -j ACCEPT + {% if BetweenClients_DROP is defined and BetweenClients_DROP == "Y" %} +# Drop traffic between VPN clients -A FORWARD -s {{ vpn_network }} -d {{ vpn_network }} -j DROP {% endif %} + +# Forward any packet that's part of an established connection -A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT +# Drop SMB/CIFS traffic that requests to be forwarded -A FORWARD -p tcp --dport 445 -j DROP +# Drop NETBIOS trafic that requests to be forwarded -A FORWARD -p udp -m multiport --ports 137,138 -j DROP -A FORWARD -p tcp -m multiport --ports 137,139 -j DROP + +# Forward any IPSEC traffic from the VPN network -A FORWARD -m conntrack --ctstate NEW -s {{ vpn_network }} -m policy --pol ipsec --dir in -j ACCEPT + COMMIT diff --git a/roles/vpn/templates/rules.v6.j2 b/roles/vpn/templates/rules.v6.j2 index 717b887..82ca8e1 100644 --- a/roles/vpn/templates/rules.v6.j2 +++ b/roles/vpn/templates/rules.v6.j2 @@ -1,43 +1,89 @@ +#### The mangle table +# This table allows us to modify packet headers +# Packets enter this table first +# *mangle + :PREROUTING ACCEPT [0:0] :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] + {% if max_mss is defined %} +# MSS is the TCP Max Segment Size +# See rules.v4 for a more complete explanation -A FORWARD -s {{ vpn_network_ipv6 }} -p tcp -m tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss {{ max_mss }} {% endif %} + COMMIT + +#### The nat table +# This table enables Network Address Translation +# (This is technically a type of packet mangling) +# *nat + :PREROUTING ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] + +# Allow traffic from the VPN network to the outside world, and replies -A POSTROUTING -s {{ vpn_network_ipv6 }} -m policy --pol none --dir out -j MASQUERADE + COMMIT + +#### The filter table +# The default ipfilter table +# *filter + +# By default, drop packets that are destined for this server :INPUT DROP [0:0] +# By default, drop packets that request to be forwarded by this server :FORWARD DROP [0:0] +# By default, accept any packets originating from this server :OUTPUT ACCEPT [0:0] + +# Create the ICMPV6-CHECK chain and its log chain +# These chains are used later to prevent a type of bug that would +# allow malicious traffic to reach over the server into the private network +# An instance of such a bug on Cisco software is described here: +# https://www.insinuator.net/2016/05/cve-2016-1409-ipv6-ndp-dos-vulnerability-in-cisco-software/ +# other software implementations might be at least as broken as the one in CISCO gear. :ICMPV6-CHECK - [0:0] :ICMPV6-CHECK-LOG - [0:0] + +# Accept packets destined for localhost -A INPUT -i lo -j ACCEPT +# Accept any packet from an open TCP connection -A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT +# Accept packets using the encapsulation protocol -A INPUT -p esp -j ACCEPT -A INPUT -m ah -j ACCEPT # rate limit ICMP traffic per source -A INPUT -p icmpv6 --icmpv6-type echo-request -m hashlimit --hashlimit-upto 5/s --hashlimit-mode srcip --hashlimit-srcmask 32 --hashlimit-name icmp-echo-drop -j ACCEPT +# Accept IPSEC traffic to ports 500 (IPSEC) and 4500 (MOBIKE aka IKE + NAT traversal) -A INPUT -p udp -m multiport --dports 500,4500 -j ACCEPT +# Allow new traffic to port 22 (SSH) -A INPUT -p tcp --dport 22 -m conntrack --ctstate NEW -j ACCEPT + +# Accept properly formatted Neighbor Discovery Protocol packets -A INPUT -p icmpv6 --icmpv6-type router-advertisement -m hl --hl-eq 255 -j ACCEPT -A INPUT -p icmpv6 --icmpv6-type neighbor-solicitation -m hl --hl-eq 255 -j ACCEPT -A INPUT -p icmpv6 --icmpv6-type neighbor-advertisement -m hl --hl-eq 255 -j ACCEPT -A INPUT -p icmpv6 --icmpv6-type redirect -m hl --hl-eq 255 -j ACCEPT + # DHCP in AWS -A INPUT -m conntrack --ctstate NEW -m udp -p udp --dport 546 -d fe80::/64 -j ACCEPT + # TODO: # The IP of the resolver should be bound to a DUMMY interface. # DUMMY interfaces are the proper way to install IPs without assigning them any # particular virtual (tun,tap,...) or physical (ethernet) interface. + +# Accept DNS traffic to the local DNS resolver -A INPUT -d fcaa::1 -p udp --dport 53 -j ACCEPT + {% if BetweenClients_DROP is defined and BetweenClients_DROP == "Y" %} -A FORWARD -s {{ vpn_network_ipv6 }} -d {{ vpn_network_ipv6 }} -j DROP {% endif %} @@ -47,13 +93,13 @@ COMMIT -A FORWARD -p tcp -m multiport --ports 137,139 -j DROP -A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT -A FORWARD -m conntrack --ctstate NEW -s {{ vpn_network_ipv6 }} -m policy --pol ipsec --dir in -j ACCEPT -# this is so potential malicious traffic can not reach anywhere over the server -# https://www.insinuator.net/2016/05/cve-2016-1409-ipv6-ndp-dos-vulnerability-in-cisco-software/ -# other software implementations might be at least as broken as the one in CISCO gear. + +# Use the ICMPV6-CHECK chain, described above -A ICMPV6-CHECK -p icmpv6 -m hl ! --hl-eq 255 --icmpv6-type router-solicitation -j ICMPV6-CHECK-LOG -A ICMPV6-CHECK -p icmpv6 -m hl ! --hl-eq 255 --icmpv6-type router-advertisement -j ICMPV6-CHECK-LOG -A ICMPV6-CHECK -p icmpv6 -m hl ! --hl-eq 255 --icmpv6-type neighbor-solicitation -j ICMPV6-CHECK-LOG -A ICMPV6-CHECK -p icmpv6 -m hl ! --hl-eq 255 --icmpv6-type neighbor-advertisement -j ICMPV6-CHECK-LOG -A ICMPV6-CHECK-LOG -j LOG --log-prefix "ICMPV6-CHECK-LOG DROP " -A ICMPV6-CHECK-LOG -j DROP + COMMIT