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This commit is contained in:
Knut Ahlers 2016-07-25 00:51:25 +02:00
parent 5cd6146e9e
commit 1249251a61
Signed by: luzifer
GPG key ID: DC2729FDD34BE99E
8 changed files with 792 additions and 0 deletions
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.gitignore vendored Normal file
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vault-openvpn

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example/living-example/README.md Normal file
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# Example: living-example
This example is the configuration I'm running for my personal VPN connection. Sure there are some modifications but that are customizations not relevant for this project.
## How to set up the server?
- Edit the `cloud-init.yml` file and set your own variables in `/etc/script_env`
- Create a DigitalOcean droplet using this config
- Replace the `myserver.com` part in the `client.conf` with your IP
- Generate a server configuration and put it into `/etc/openvpn/server.conf`
```bash
# vault-openvpn --auto-revoke --pki-mountpoint luzifer_io server edda.openvpn.luzifer.io
server 10.231.0.0 255.255.255.0
route 10.231.0.0 255.255.255.0
[...]
```
- Ensure the server has finished generating `dh.pem` and reload the config: `systemctl restart openvpn`
- Generate a client configuration and put it into Tunnelblick or any other client software you like:
```bash
# vault-openvpn --auto-revoke --pki-mountpoint luzifer_io client knut-ws02.openvpn.luzifer.io
remote myserver.com 1194 udp
client
nobind
dev tap
<ca>
[...]
```

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example/living-example/client.conf Normal file
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remote myserver.com 1194 udp
client
nobind
dev tap
<ca>
{{ .CertAuthority }}
</ca>
<cert>
{{ .Certificate }}
</cert>
<key>
{{ .PrivateKey }}
</key>

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example/living-example/cloud-init.yml Normal file
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#cloud-config
packages:
- openvpn
write_files:
- content: |
VAULT_ADDR="https://..."
PKI_PATH="${VAULT_ADDR}/v1/luzifer_io"
path: /etc/script_env
owner: root:root
permissions: '0600'
- content: |
#!/bin/bash -ex
source /etc/script_env
sed -i 's/#AUTOSTART="all"/AUTOSTART="all"/' /etc/default/openvpn
systemctl daemon-reload
openssl dhparam -out /etc/openvpn/dh2048.pem 2048
/usr/local/bin/refresh_crl
path: /tmp/setup.sh
owner: root:root
permissions: '0755'
- content: |
#!/bin/bash -ex
source /etc/script_env
curl -sSLo /tmp/crl.pem ${PKI_PATH}/crl/pem
if ! ( diff -wq /etc/openvpn/crl.pem /tmp/crl.pem ); then
mv /tmp/crl.pem /etc/openvpn/crl.pem
fi
path: /usr/local/bin/refresh_crl
owner: root:root
permissions: '0755'
- content: |
*/5 * * * * root /usr/local/bin/refresh_crl
path: /etc/cron.d/openvpn
owner: root:root
runcmd:
- [ /tmp/setup.sh ]

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example/living-example/server.conf Normal file
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server 10.231.0.0 255.255.255.0
route 10.231.0.0 255.255.255.0
keepalive 5 30
persist-key
persist-tun
proto udp
port 1194
dev tap
status /var/log/openvpn-status.log
client-to-client
ifconfig-pool-persist /etc/openvpn/ipp.txt
verb 3
push dhcp-option DNS 8.8.8.8
push dhcp-option DNS 8.8.4.4
dh /etc/openvpn/dh2048.pem
crl-verify /etc/openvpn/crl.pem
<ca>
{{ .CertAuthority }}
</ca>
<cert>
{{ .Certificate }}
</cert>
<key>
{{ .PrivateKey }}
</key>

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example/openvpn-sample/client.conf Normal file
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##############################################
# Sample client-side OpenVPN 2.0 config file #
# for connecting to multi-client server. #
# #
# This configuration can be used by multiple #
# clients, however each client should have #
# its own cert and key files. #
# #
# On Windows, you might want to rename this #
# file so it has a .ovpn extension #
##############################################
# Specify that we are a client and that we
# will be pulling certain config file directives
# from the server.
client
# Use the same setting as you are using on
# the server.
# On most systems, the VPN will not function
# unless you partially or fully disable
# the firewall for the TUN/TAP interface.
;dev tap
dev tun
# Windows needs the TAP-Windows adapter name
# from the Network Connections panel
# if you have more than one. On XP SP2,
# you may need to disable the firewall
# for the TAP adapter.
;dev-node MyTap
# Are we connecting to a TCP or
# UDP server? Use the same setting as
# on the server.
;proto tcp
proto udp
# The hostname/IP and port of the server.
# You can have multiple remote entries
# to load balance between the servers.
remote my-server-1 1194
;remote my-server-2 1194
# Choose a random host from the remote
# list for load-balancing. Otherwise
# try hosts in the order specified.
;remote-random
# Keep trying indefinitely to resolve the
# host name of the OpenVPN server. Very useful
# on machines which are not permanently connected
# to the internet such as laptops.
resolv-retry infinite
# Most clients don't need to bind to
# a specific local port number.
nobind
# Downgrade privileges after initialization (non-Windows only)
;user nobody
;group nobody
# Try to preserve some state across restarts.
persist-key
persist-tun
# If you are connecting through an
# HTTP proxy to reach the actual OpenVPN
# server, put the proxy server/IP and
# port number here. See the man page
# if your proxy server requires
# authentication.
;http-proxy-retry # retry on connection failures
;http-proxy [proxy server] [proxy port #]
# Wireless networks often produce a lot
# of duplicate packets. Set this flag
# to silence duplicate packet warnings.
;mute-replay-warnings
# SSL/TLS parms.
# See the server config file for more
# description. It's best to use
# a separate .crt/.key file pair
# for each client. A single ca
# file can be used for all clients.
<ca>
{{ .CertAuthority }}
</ca>
<cert>
{{ .Certificate }}
</cert>
<key>
{{ .PrivateKey }}
</key>
# Verify server certificate by checking
# that the certicate has the nsCertType
# field set to "server". This is an
# important precaution to protect against
# a potential attack discussed here:
# http://openvpn.net/howto.html#mitm
#
# To use this feature, you will need to generate
# your server certificates with the nsCertType
# field set to "server". The build-key-server
# script in the easy-rsa folder will do this.
;ns-cert-type server
# If a tls-auth key is used on the server
# then every client must also have the key.
;tls-auth ta.key 1
# Select a cryptographic cipher.
# If the cipher option is used on the server
# then you must also specify it here.
;cipher x
# Enable compression on the VPN link.
# Don't enable this unless it is also
# enabled in the server config file.
comp-lzo
# Set log file verbosity.
verb 3
# Silence repeating messages
;mute 20

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#################################################
# Sample OpenVPN 2.0 config file for #
# multi-client server. #
# #
# This file is for the server side #
# of a many-clients one-server #
# OpenVPN configuration. #
# #
# OpenVPN also supports #
# single-machine single-machine #
# configurations (See the Examples page #
# on the web site for more info). #
# #
# This config should work on Windows #
# or Linux/BSD systems. Remember on #
# Windows to quote pathnames and use #
# double backslashes, e.g.: #
# "C:\\Program Files\\OpenVPN\\config\\foo.key" #
# #
# Comments are preceded with '#' or ';' #
#################################################
# Which local IP address should OpenVPN
# listen on? (optional)
;local a.b.c.d
# Which TCP/UDP port should OpenVPN listen on?
# If you want to run multiple OpenVPN instances
# on the same machine, use a different port
# number for each one. You will need to
# open up this port on your firewall.
port 1194
# TCP or UDP server?
;proto tcp
proto udp
# "dev tun" will create a routed IP tunnel,
# "dev tap" will create an ethernet tunnel.
# Use "dev tap0" if you are ethernet bridging
# and have precreated a tap0 virtual interface
# and bridged it with your ethernet interface.
# If you want to control access policies
# over the VPN, you must create firewall
# rules for the the TUN/TAP interface.
# On non-Windows systems, you can give
# an explicit unit number, such as tun0.
# On Windows, use "dev-node" for this.
# On most systems, the VPN will not function
# unless you partially or fully disable
# the firewall for the TUN/TAP interface.
;dev tap
dev tun
# Windows needs the TAP-Windows adapter name
# from the Network Connections panel if you
# have more than one. On XP SP2 or higher,
# you may need to selectively disable the
# Windows firewall for the TAP adapter.
# Non-Windows systems usually don't need this.
;dev-node MyTap
# SSL/TLS root certificate (ca), certificate
# (cert), and private key (key). Each client
# and the server must have their own cert and
# key file. The server and all clients will
# use the same ca file.
#
# See the "easy-rsa" directory for a series
# of scripts for generating RSA certificates
# and private keys. Remember to use
# a unique Common Name for the server
# and each of the client certificates.
#
# Any X509 key management system can be used.
# OpenVPN can also use a PKCS #12 formatted key file
# (see "pkcs12" directive in man page).
<ca>
{{ .CertAuthority }}
</ca>
<cert>
{{ .Certificate }}
</cert>
<key>
{{ .PrivateKey }}
</key>
# Diffie hellman parameters.
# Generate your own with:
# openssl dhparam -out dh1024.pem 1024
# Substitute 2048 for 1024 if you are using
# 2048 bit keys.
dh dh1024.pem
# Configure server mode and supply a VPN subnet
# for OpenVPN to draw client addresses from.
# The server will take 10.8.0.1 for itself,
# the rest will be made available to clients.
# Each client will be able to reach the server
# on 10.8.0.1. Comment this line out if you are
# ethernet bridging. See the man page for more info.
server 10.8.0.0 255.255.255.0
# Maintain a record of client virtual IP address
# associations in this file. If OpenVPN goes down or
# is restarted, reconnecting clients can be assigned
# the same virtual IP address from the pool that was
# previously assigned.
ifconfig-pool-persist ipp.txt
# Configure server mode for ethernet bridging.
# You must first use your OS's bridging capability
# to bridge the TAP interface with the ethernet
# NIC interface. Then you must manually set the
# IP/netmask on the bridge interface, here we
# assume 10.8.0.4/255.255.255.0. Finally we
# must set aside an IP range in this subnet
# (start=10.8.0.50 end=10.8.0.100) to allocate
# to connecting clients. Leave this line commented
# out unless you are ethernet bridging.
;server-bridge 10.8.0.4 255.255.255.0 10.8.0.50 10.8.0.100
# Push routes to the client to allow it
# to reach other private subnets behind
# the server. Remember that these
# private subnets will also need
# to know to route the OpenVPN client
# address pool (10.8.0.0/255.255.255.0)
# back to the OpenVPN server.
;push "route 192.168.10.0 255.255.255.0"
;push "route 192.168.20.0 255.255.255.0"
# To assign specific IP addresses to specific
# clients or if a connecting client has a private
# subnet behind it that should also have VPN access,
# use the subdirectory "ccd" for client-specific
# configuration files (see man page for more info).
# EXAMPLE: Suppose the client
# having the certificate common name "Thelonious"
# also has a small subnet behind his connecting
# machine, such as 192.168.40.128/255.255.255.248.
# First, uncomment out these lines:
;client-config-dir ccd
;route 192.168.40.128 255.255.255.248
# Then create a file ccd/Thelonious with this line:
# iroute 192.168.40.128 255.255.255.248
# This will allow Thelonious' private subnet to
# access the VPN. This example will only work
# if you are routing, not bridging, i.e. you are
# using "dev tun" and "server" directives.
# EXAMPLE: Suppose you want to give
# Thelonious a fixed VPN IP address of 10.9.0.1.
# First uncomment out these lines:
;client-config-dir ccd
;route 10.9.0.0 255.255.255.252
# Then add this line to ccd/Thelonious:
# ifconfig-push 10.9.0.1 10.9.0.2
# Suppose that you want to enable different
# firewall access policies for different groups
# of clients. There are two methods:
# (1) Run multiple OpenVPN daemons, one for each
# group, and firewall the TUN/TAP interface
# for each group/daemon appropriately.
# (2) (Advanced) Create a script to dynamically
# modify the firewall in response to access
# from different clients. See man
# page for more info on learn-address script.
;learn-address ./script
# If enabled, this directive will configure
# all clients to redirect their default
# network gateway through the VPN, causing
# all IP traffic such as web browsing and
# and DNS lookups to go through the VPN
# (The OpenVPN server machine may need to NAT
# the TUN/TAP interface to the internet in
# order for this to work properly).
# CAVEAT: May break client's network config if
# client's local DHCP server packets get routed
# through the tunnel. Solution: make sure
# client's local DHCP server is reachable via
# a more specific route than the default route
# of 0.0.0.0/0.0.0.0.
;push "redirect-gateway"
# Certain Windows-specific network settings
# can be pushed to clients, such as DNS
# or WINS server addresses. CAVEAT:
# http://openvpn.net/faq.html#dhcpcaveats
;push "dhcp-option DNS 10.8.0.1"
;push "dhcp-option WINS 10.8.0.1"
# Uncomment this directive to allow different
# clients to be able to "see" each other.
# By default, clients will only see the server.
# To force clients to only see the server, you
# will also need to appropriately firewall the
# server's TUN/TAP interface.
;client-to-client
# Uncomment this directive if multiple clients
# might connect with the same certificate/key
# files or common names. This is recommended
# only for testing purposes. For production use,
# each client should have its own certificate/key
# pair.
#
# IF YOU HAVE NOT GENERATED INDIVIDUAL
# CERTIFICATE/KEY PAIRS FOR EACH CLIENT,
# EACH HAVING ITS OWN UNIQUE "COMMON NAME",
# UNCOMMENT THIS LINE OUT.
;duplicate-cn
# The keepalive directive causes ping-like
# messages to be sent back and forth over
# the link so that each side knows when
# the other side has gone down.
# Ping every 10 seconds, assume that remote
# peer is down if no ping received during
# a 120 second time period.
keepalive 10 120
# For extra security beyond that provided
# by SSL/TLS, create an "HMAC firewall"
# to help block DoS attacks and UDP port flooding.
#
# Generate with:
# openvpn --genkey --secret ta.key
#
# The server and each client must have
# a copy of this key.
# The second parameter should be '0'
# on the server and '1' on the clients.
;tls-auth ta.key 0 # This file is secret
# Select a cryptographic cipher.
# This config item must be copied to
# the client config file as well.
;cipher BF-CBC # Blowfish (default)
;cipher AES-128-CBC # AES
;cipher DES-EDE3-CBC # Triple-DES
# Enable compression on the VPN link.
# If you enable it here, you must also
# enable it in the client config file.
comp-lzo
# The maximum number of concurrently connected
# clients we want to allow.
;max-clients 100
# It's a good idea to reduce the OpenVPN
# daemon's privileges after initialization.
#
# You can uncomment this out on
# non-Windows systems.
;user nobody
;group nobody
# The persist options will try to avoid
# accessing certain resources on restart
# that may no longer be accessible because
# of the privilege downgrade.
persist-key
persist-tun
# Output a short status file showing
# current connections, truncated
# and rewritten every minute.
status openvpn-status.log
# By default, log messages will go to the syslog (or
# on Windows, if running as a service, they will go to
# the "\Program Files\OpenVPN\log" directory).
# Use log or log-append to override this default.
# "log" will truncate the log file on OpenVPN startup,
# while "log-append" will append to it. Use one
# or the other (but not both).
;log openvpn.log
;log-append openvpn.log
# Set the appropriate level of log
# file verbosity.
#
# 0 is silent, except for fatal errors
# 4 is reasonable for general usage
# 5 and 6 can help to debug connection problems
# 9 is extremely verbose
verb 3
# Silence repeating messages. At most 20
# sequential messages of the same message
# category will be output to the log.
;mute 20

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package main
import (
"crypto/x509"
"encoding/pem"
"errors"
"fmt"
"io/ioutil"
"log"
"os"
"strings"
"text/template"
"time"
"github.com/Luzifer/go_helpers/str"
"github.com/Luzifer/rconfig"
"github.com/hashicorp/vault/api"
homedir "github.com/mitchellh/go-homedir"
)
const (
actionRevoke = "revoke"
actionMakeClientConfig = "client"
actionMakeServerConfig = "server"
)
var (
cfg = struct {
VaultAddress string `flag:"vault-addr" env:"VAULT_ADDR" default:"https://127.0.0.1:8200" description:"Vault API address"`
VaultToken string `flag:"vault-token" env:"VAULT_TOKEN" vardefault:"vault-token" description:"Specify a token to use instead of app-id auth"`
PKIMountPoint string `flag:"pki-mountpoint" default:"/pki" description:"Path the PKI provider is mounted to"`
PKIRole string `flag:"pki-role" default:"openvpn" description:"Role defined in the PKI usable by the token and able to write the specified FQDN"`
AutoRevoke bool `flag:"auto-revoke" default:"false" description:"Automatically revoke older certificates for this FQDN"`
CertTTL time.Duration `flag:"ttl" default:"8760h" description:"Set the TTL for this certificate"`
VersionAndExit bool `flag:"version" default:"false" description:"Prints current version and exits"`
}{}
version = "dev"
client *api.Client
)
type templateVars struct {
CertAuthority string
Certificate string
PrivateKey string
}
func vaultTokenFromDisk() string {
vf, err := homedir.Expand("~/.vault-token")
if err != nil {
return ""
}
data, err := ioutil.ReadFile(vf)
if err != nil {
return ""
}
return string(data)
}
func init() {
rconfig.SetVariableDefaults(map[string]string{
"vault-token": vaultTokenFromDisk(),
})
if err := rconfig.Parse(&cfg); err != nil {
log.Fatalf("Unable to parse commandline options: %s", err)
}
if cfg.VersionAndExit {
fmt.Printf("vault-openvpn %s\n", version)
os.Exit(0)
}
if cfg.VaultToken == "" {
log.Fatalf("[ERR] You need to set vault-token")
}
}
func main() {
if len(rconfig.Args()) != 3 {
fmt.Println("Usage: vault-openvpn [options] <action> <FQDN>")
fmt.Println(" actions: client / server / revoke")
os.Exit(1)
}
action := rconfig.Args()[1]
fqdn := rconfig.Args()[2]
if !str.StringInSlice(action, []string{actionRevoke, actionMakeClientConfig, actionMakeServerConfig}) {
log.Fatalf("Unknown action: %s", action)
}
var err error
client, err = api.NewClient(&api.Config{
Address: cfg.VaultAddress,
})
if err != nil {
log.Fatalf("Could not create Vault client: %s", err)
}
client.SetToken(cfg.VaultToken)
if cfg.AutoRevoke || action == actionRevoke {
if err := revokeOlderCertificate(fqdn); err != nil {
log.Fatalf("Could not revoke certificate: %s", err)
}
}
if action != actionMakeClientConfig && action != actionMakeServerConfig {
return
}
tplName := "client.conf"
if action == actionMakeServerConfig {
tplName = "server.conf"
}
caCert, err := getCACert()
if err != nil {
log.Fatalf("Could not load CA certificate: %s", err)
}
tplv, err := generateCertificate(fqdn)
if err != nil {
log.Fatalf("Could not generate new certificate: %s", err)
}
tplv.CertAuthority = caCert
if err := renderTemplate(tplName, tplv); err != nil {
log.Fatalf("Could not render configuration: %s", err)
}
}
func renderTemplate(tplName string, tplv *templateVars) error {
raw, err := ioutil.ReadFile(tplName)
if err != nil {
return err
}
tpl, err := template.New("tpl").Parse(string(raw))
if err != nil {
return err
}
return tpl.Execute(os.Stdout, tplv)
}
func revokeOlderCertificate(fqdn string) error {
path := strings.Join([]string{strings.Trim(cfg.PKIMountPoint, "/"), "certs"}, "/")
secret, err := client.Logical().List(path)
if err != nil {
return err
}
if secret.Data == nil {
return errors.New("Got no data from backend")
}
for _, serial := range secret.Data["keys"].([]interface{}) {
path := strings.Join([]string{strings.Trim(cfg.PKIMountPoint, "/"), "cert", serial.(string)}, "/")
cs, err := client.Logical().Read(path)
if err != nil {
errors.New("Unable to read certificate: " + err.Error())
}
cn, err := commonNameFromCertificate(cs.Data["certificate"].(string))
if err != nil {
return err
}
log.Printf("Found certificate %s with CN %s", serial, cn)
if cn == fqdn {
path := strings.Join([]string{strings.Trim(cfg.PKIMountPoint, "/"), "revoke"}, "/")
if _, err := client.Logical().Write(path, map[string]interface{}{
"serial_number": serial.(string),
}); err != nil {
return errors.New("Revoke of serial " + serial.(string) + " failed: " + err.Error())
}
log.Printf("Revoked certificate %s", serial)
}
}
return nil
}
func commonNameFromCertificate(pemString string) (string, error) {
data, _ := pem.Decode([]byte(pemString))
cert, err := x509.ParseCertificate(data.Bytes)
if err != nil {
return "", err
}
return cert.Subject.CommonName, nil
}
func getCACert() (string, error) {
path := strings.Join([]string{strings.Trim(cfg.PKIMountPoint, "/"), "cert", "ca"}, "/")
cs, err := client.Logical().Read(path)
if err != nil {
errors.New("Unable to read certificate: " + err.Error())
}
return cs.Data["certificate"].(string), nil
}
func generateCertificate(fqdn string) (*templateVars, error) {
path := strings.Join([]string{strings.Trim(cfg.PKIMountPoint, "/"), "issue", cfg.PKIRole}, "/")
secret, err := client.Logical().Write(path, map[string]interface{}{
"common_name": fqdn,
"ttl": cfg.CertTTL.String(),
})
if err != nil {
return nil, err
}
if secret.Data == nil {
return nil, errors.New("Got no data from backend")
}
return &templateVars{
Certificate: secret.Data["certificate"].(string),
PrivateKey: secret.Data["private_key"].(string),
}, nil
}