* Refactor StrongSwan PKI automation with Ansible crypto modules - Replace shell-based OpenSSL commands with community.crypto modules - Remove custom OpenSSL config template and manual file management - Upgrade Ansible to 11.8.0 in requirements.txt - Improve idempotency, maintainability, and security of certificate and CRL handling * Enhance nameConstraints with comprehensive exclusions - Add email domain exclusions (.com, .org, .net, .gov, .edu, .mil, .int) - Include private IPv4 network exclusions - Add IPv6 null route exclusion - Preserve all security constraints from original openssl.cnf.j2 - Note: Complex IPv6 conditional logic simplified for Ansible compatibility Security: Maintains defense-in-depth certificate scope restrictions * Refactor StrongSwan PKI with comprehensive security enhancements and hybrid testing ## StrongSwan PKI Modernization - Migrated from shell-based OpenSSL commands to Ansible community.crypto modules - Simplified complex Jinja2 templates while preserving all security properties - Added clear, concise comments explaining security rationale and Apple compatibility ## Enhanced Security Implementation (Issues #75, #153) - **Name constraints**: CA certificates restricted to specific IP/email domains - **EKU role separation**: Server certs (serverAuth only) vs client certs (clientAuth only) - **Domain exclusions**: Blocks public domains (.com, .org, etc.) and private IP ranges - **Apple compatibility**: SAN extensions and PKCS#12 compatibility2022 encryption - **Certificate revocation**: Automated CRL generation for removed users ## Comprehensive Test Suite - **Hybrid testing**: Validates real certificates when available, config validation for CI - **Security validation**: Verifies name constraints, EKU restrictions, role separation - **Apple compatibility**: Tests SAN extensions and PKCS#12 format compliance - **Certificate chain**: Validates CA signing and certificate validity periods - **CI-compatible**: No deployment required, tests Ansible configuration directly ## Configuration Updates - Updated CLAUDE.md: Ansible version rationale (stay current for security/performance) - Streamlined comments: Removed duplicative explanations while preserving technical context - Maintained all Issue #75/#153 security enhancements with modern Ansible approach 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Fix linting issues across the codebase ## Python Code Quality (ruff) - Fixed import organization and removed unused imports in test files - Replaced `== True` comparisons with direct boolean checks - Added noqa comments for intentional imports in test modules ## YAML Formatting (yamllint) - Removed trailing spaces in openssl.yml comments - All YAML files now pass yamllint validation (except one pre-existing long regex line) ## Code Consistency - Maintained proper import ordering in test files - Ensured all code follows project linting standards - Ready for CI pipeline validation 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Replace magic number with configurable certificate validity period ## Maintainability Improvement - Replaced hardcoded `+3650d` (10 years) with configurable variable - Added `certificate_validity_days: 3650` in vars section with clear documentation - Applied consistently to both server and client certificate signing ## Benefits - Single location to modify certificate validity period - Supports compliance requirements for shorter certificate lifespans - Improves code readability and maintainability - Eliminates magic number duplication ## Backwards Compatibility - Default remains 10 years (3650 days) - no behavior change - Organizations can now easily customize certificate validity as needed 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Update test to validate configurable certificate validity period ## Test Update - Fixed test failure after replacing magic number with configurable variable - Now validates both variable definition and usage patterns: - `certificate_validity_days: 3650` (configurable parameter) - `ownca_not_after: "+{{ certificate_validity_days }}d"` (variable usage) ## Improved Test Coverage - Better validation: checks that validity is configurable, not hardcoded - Maintains backwards compatibility verification (10-year default) - Ensures proper Ansible variable templating is used ## Verified - Config validation mode: All 6 tests pass ✓ - Validates the maintainability improvement from previous commit 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Update to Python 3.11 minimum and fix IPv6 constraint format - Update Python requirement from 3.10 to 3.11 to align with Ansible 11 - Pin Ansible collections in requirements.yml for stability - Fix invalid IPv6 constraint format causing deployment failure - Update ruff target-version to py311 for consistency 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Fix x509_crl mode parameter and auto-fix Python linting - Remove deprecated 'mode' parameter from x509_crl task - Add separate file task to set CRL permissions (0644) - Auto-fix Python datetime import (use datetime.UTC alias) 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Fix final IPv6 constraint format in defaults template - Update nameConstraints template in defaults/main.yml - Change malformed IP:0:0:0:0:0:0:0:0/0:0:0:0:0:0:0:0 to correct IP:::/0 - This ensures both Ansible crypto modules and OpenSSL template use consistent IPv6 format * Fix critical certificate generation issues for macOS/iOS VPN compatibility This commit addresses multiple certificate generation bugs in the Ansible crypto module implementation that were causing VPN authentication failures on Apple devices. Fixes implemented: 1. **Basic Constraints Extension**: Added missing `CA:FALSE` constraints to both server and client certificate CSRs. This was causing certificate chain validation errors on macOS/iOS devices. 2. **Subject Key Identifier**: Added `create_subject_key_identifier: true` to CA certificate generation to enable proper Authority Key Identifier creation in signed certificates. 3. **Complete Name Constraints**: Fixed missing DNS and IPv6 constraints in CA certificate that were causing size differences compared to legacy shell-based generation. Now includes: - DNS constraints for the deployment-specific domain - IPv6 permitted addresses when IPv6 support is enabled - Complete IPv6 exclusion ranges (fc00::/7, fe80::/10, 2001:db8::/32) These changes bring the certificate format much closer to the working shell-based implementation and should resolve most macOS/iOS VPN connectivity issues. **Outstanding Issue**: Authority Key Identifier still incomplete - missing DirName and serial components. The community.crypto module limitation may require additional investigation or alternative approaches. Certificate size improvements: Server certificates increased from ~750 to ~775 bytes, CA certificates from ~1070 to ~1250 bytes, bringing them closer to the expected ~3000 byte target size. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Fix certificate generation and improve version parsing This commit addresses multiple issues found during macOS certificate validation: Certificate Generation Fixes: - Add Basic Constraints (CA:FALSE) to server and client certificates - Generate Subject Key Identifier for proper AKI creation - Improve Name Constraints implementation for security - Update community.crypto to version 3.0.3 for latest fixes Code Quality Improvements: - Clean up certificate comments and remove obsolete references - Fix server certificate identification in tests - Update datetime comparisons for cryptography library compatibility - Fix Ansible version parsing in main.yml with proper regex handling Testing: - All certificate validation tests pass - Ansible syntax checks pass - Python linting (ruff) clean - YAML linting (yamllint) clean These changes restore macOS/iOS certificate compatibility while maintaining security best practices and improving code maintainability. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Enhance security documentation with comprehensive inline comments Add detailed technical explanations for critical PKI security features: - Name Constraints: Defense-in-depth rationale and attack prevention - Public domain/network exclusions: Impersonation attack prevention - RFC 1918 private IP blocking: Lateral movement prevention - IPv6 constraint strategy: ULA/link-local/documentation range handling - Role separation enforcement: Server vs client EKU restrictions - CA delegation prevention: pathlen:0 security implications - Cross-deployment isolation: UUID-based certificate scope limiting These comments provide essential context for maintainers to understand the security importance of each configuration without referencing external issue numbers, ensuring long-term maintainability. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Fix CI test failures in PKI certificate validation Resolve Smart Test Selection workflow failures by fixing test validation logic: **Certificate Configuration Fixes:** - Remove unnecessary serverAuth/clientAuth EKUs from CA certificate - CA now only has IPsec End Entity EKU for VPN-specific certificate issuance - Maintains proper role separation between server and client certificates **Test Validation Improvements:** - Fix domain exclusion detection to handle both single and double quotes in YAML - Improve EKU validation to check actual configuration lines, not comments - Server/client certificate tests now correctly parse YAML structure - Tests pass in both CI mode (config validation) and local mode (real certificates) **Root Cause:** The CI failures were caused by overly broad test assertions that: 1. Expected double-quoted strings but found single-quoted YAML 2. Detected EKU keywords in comments rather than actual configuration 3. Failed to properly parse YAML list structures All security constraints remain intact - no actual security issues were present. The certificate generation produces properly constrained certificates for VPN use. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Fix trailing space in openssl.yml for yamllint compliance --------- Co-authored-by: Dan Guido <dan@trailofbits.com> Co-authored-by: Claude <noreply@anthropic.com> |
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.github | ||
configs | ||
docs | ||
files/cloud-init | ||
library | ||
playbooks | ||
roles | ||
scripts | ||
tests | ||
venvs | ||
.ansible-lint | ||
.dockerignore | ||
.gitignore | ||
.yamllint | ||
algo | ||
algo-docker.sh | ||
algo-showenv.sh | ||
ansible.cfg | ||
CHANGELOG.md | ||
CLAUDE.md | ||
cloud.yml | ||
CODEOWNERS | ||
config.cfg | ||
CONTRIBUTING.md | ||
deploy_client.yml | ||
Dockerfile | ||
input.yml | ||
install.sh | ||
inventory | ||
LICENSE | ||
logo.png | ||
main.yml | ||
Makefile | ||
PERFORMANCE.md | ||
PULL_REQUEST_TEMPLATE.md | ||
pyproject.toml | ||
README.md | ||
requirements.txt | ||
requirements.yml | ||
SECURITY.md | ||
server.yml | ||
users.yml | ||
uv.lock | ||
Vagrantfile |
Algo VPN
Algo VPN is a set of Ansible scripts that simplify the setup of a personal WireGuard and IPsec VPN. It uses the most secure defaults available and works with common cloud providers. See our release announcement for more information.
Features
- Supports only IKEv2 with strong crypto (AES-GCM, SHA2, and P-256) for iOS, macOS, and Linux
- Supports WireGuard for all of the above, in addition to Android and Windows 11
- Generates .conf files and QR codes for iOS, macOS, Android, and Windows WireGuard clients
- Generates Apple profiles to auto-configure iOS and macOS devices for IPsec - no client software required
- Includes a helper script to add and remove users
- Blocks ads with a local DNS resolver (optional)
- Sets up limited SSH users for tunneling traffic (optional)
- Based on current versions of Ubuntu and strongSwan
- Installs to DigitalOcean, Amazon Lightsail, Amazon EC2, Vultr, Microsoft Azure, Google Compute Engine, Scaleway, OpenStack, CloudStack, Hetzner Cloud, Linode, or your own Ubuntu server (for more advanced users)
Anti-features
- Does not support legacy cipher suites or protocols like L2TP, IKEv1, or RSA
- Does not install Tor, OpenVPN, or other risky servers
- Does not depend on the security of TLS
- Does not claim to provide anonymity or censorship avoidance
- Does not claim to protect you from the FSB, MSS, DGSE, or FSM
Deploy the Algo Server
The easiest way to get an Algo server running is to run it on your local system or from Google Cloud Shell and let it set up a new virtual machine in the cloud for you.
-
Setup an account on a cloud hosting provider. Algo supports DigitalOcean (most user friendly), Amazon Lightsail, Amazon EC2, Vultr, Microsoft Azure, Google Compute Engine, Scaleway, DreamCompute, Linode, or other OpenStack-based cloud hosting, Exoscale or other CloudStack-based cloud hosting, or Hetzner Cloud.
-
Get a copy of Algo. The Algo scripts will be installed on your local system. There are two ways to get a copy:
-
Download the ZIP file. Unzip the file to create a directory named
algo-master
containing the Algo scripts. -
Use
git clone
to create a directory namedalgo
containing the Algo scripts:git clone https://github.com/trailofbits/algo.git
-
-
Install Algo's core dependencies. Algo requires that Python 3.10 and at least one supporting package are installed on your system.
-
macOS: Big Sur (11.0) and higher includes Python 3 as part of the optional Command Line Developer Tools package. From Terminal run:
python3 -m pip install --user --upgrade virtualenv
If prompted, install the Command Line Developer Tools and re-run the above command.
For macOS versions prior to Big Sur, see Deploy from macOS for information on installing Python 3 .
-
Linux: Recent releases of Ubuntu, Debian, and Fedora come with Python 3 already installed. If your Python version is not 3.10, then you will need to use pyenv to install Python 3.10. Make sure your system is up-to-date and install the supporting package(s):
-
Ubuntu and Debian:
sudo apt install -y --no-install-recommends python3-virtualenv file lookup
On a Raspberry Pi running Ubuntu also install
libffi-dev
andlibssl-dev
. -
Fedora:
sudo dnf install -y python3-virtualenv
-
-
Windows: Use the Windows Subsystem for Linux (WSL) to create your own copy of Ubuntu running under Windows from which to install and run Algo. See the Windows documentation for more information.
-
-
Install Algo's remaining dependencies. You'll need to run these commands from the Algo directory each time you download a new copy of Algo. In a Terminal window
cd
into thealgo-master
(ZIP file) oralgo
(git clone
) directory and run:python3 -m virtualenv --python="$(command -v python3)" .env && source .env/bin/activate && python3 -m pip install -U pip virtualenv && python3 -m pip install -r requirements.txt
On Fedora first run
export TMPDIR=/var/tmp
, then add the option--system-site-packages
to the first command above (afterpython3 -m virtualenv
). On macOS install the C compiler if prompted. -
Set your configuration options. Open the file
config.cfg
in your favorite text editor. Specify the users you wish to create in theusers
list. Create a unique user for each device you plan to connect to your VPN.
Note: [IKEv2 Only] If you want to add or delete users later, you must select
yes
at theDo you want to retain the keys (PKI)?
prompt during the server deployment. You should also review the other options before deployment, as changing your mind about them later may require you to deploy a brand new server.
- Start the deployment. Return to your terminal. In the Algo directory, run
./algo
and follow the instructions. There are several optional features available, none of which are required for a fully functional VPN server. These optional features are described in greater detail in here.
That's it! You will get the message below when the server deployment process completes. Take note of the p12 (user certificate) password and the CA key in case you need them later, they will only be displayed this time.
You can now set up clients to connect to your VPN. Proceed to Configure the VPN Clients below.
"# Congratulations! #"
"# Your Algo server is running. #"
"# Config files and certificates are in the ./configs/ directory. #"
"# Go to https://whoer.net/ after connecting #"
"# and ensure that all your traffic passes through the VPN. #"
"# Local DNS resolver 172.16.0.1 #"
"# The p12 and SSH keys password for new users is XXXXXXXX #"
"# The CA key password is XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX #"
"# Shell access: ssh -F configs/<server_ip>/ssh_config <hostname> #"
Configure the VPN Clients
Certificates and configuration files that users will need are placed in the configs
directory. Make sure to secure these files since many contain private keys. All files are saved under a subdirectory named with the IP address of your new Algo VPN server.
Apple Devices
WireGuard is used to provide VPN services on Apple devices. Algo generates a WireGuard configuration file, wireguard/<username>.conf
, and a QR code, wireguard/<username>.png
, for each user defined in config.cfg
.
On iOS, install the WireGuard app from the iOS App Store. Then, use the WireGuard app to scan the QR code or AirDrop the configuration file to the device.
On macOS Mojave or later, install the WireGuard app from the Mac App Store. WireGuard will appear in the menu bar once you run the app. Click on the WireGuard icon, choose Import tunnel(s) from file..., then select the appropriate WireGuard configuration file.
On either iOS or macOS, you can enable "Connect on Demand" and/or exclude certain trusted Wi-Fi networks (such as your home or work) by editing the tunnel configuration in the WireGuard app. (Algo can't do this automatically for you.)
Installing WireGuard is a little more complicated on older version of macOS. See Using macOS as a Client with WireGuard.
If you prefer to use the built-in IPSEC VPN on Apple devices, or need "Connect on Demand" or excluded Wi-Fi networks automatically configured, then see Using Apple Devices as a Client with IPSEC.
Android Devices
WireGuard is used to provide VPN services on Android. Install the WireGuard VPN Client. Import the corresponding wireguard/<name>.conf
file to your device, then setup a new connection with it. See the Android setup instructions for more detailed walkthrough.
Windows
WireGuard is used to provide VPN services on Windows. Algo generates a WireGuard configuration file, wireguard/<username>.conf
, for each user defined in config.cfg
.
Install the WireGuard VPN Client. Import the generated wireguard/<username>.conf
file to your device, then setup a new connection with it. See the Windows setup instructions for more detailed walkthrough and troubleshooting.
Linux WireGuard Clients
WireGuard works great with Linux clients. See this page for an example of how to configure WireGuard on Ubuntu.
Linux strongSwan IPsec Clients (e.g., OpenWRT, Ubuntu Server, etc.)
Please see this page.
OpenWrt Wireguard Clients
Please see this page.
Other Devices
Depending on the platform, you may need one or multiple of the following files.
- ipsec/manual/cacert.pem: CA Certificate
- ipsec/manual/.p12: User Certificate and Private Key (in PKCS#12 format)
- ipsec/manual/.conf: strongSwan client configuration
- ipsec/manual/.secrets: strongSwan client configuration
- ipsec/apple/.mobileconfig: Apple Profile
- wireguard/.conf: WireGuard configuration profile
- wireguard/.png: WireGuard configuration QR code
Setup an SSH Tunnel
If you turned on the optional SSH tunneling role, then local user accounts will be created for each user in config.cfg
and SSH authorized_key files for them will be in the configs
directory (user.pem). SSH user accounts do not have shell access, cannot authenticate with a password, and only have limited tunneling options (e.g., ssh -N
is required). This ensures that SSH users have the least access required to setup a tunnel and can perform no other actions on the Algo server.
Use the example command below to start an SSH tunnel by replacing <user>
and <ip>
with your own. Once the tunnel is setup, you can configure a browser or other application to use 127.0.0.1:1080 as a SOCKS proxy to route traffic through the Algo server:
ssh -D 127.0.0.1:1080 -f -q -C -N <user>@algo -i configs/<ip>/ssh-tunnel/<user>.pem -F configs/<ip>/ssh_config
SSH into Algo Server
Your Algo server is configured for key-only SSH access for administrative purposes. Open the Terminal app, cd
into the algo-master
directory where you originally downloaded Algo, and then use the command listed on the success message:
ssh -F configs/<ip>/ssh_config <hostname>
where <ip>
is the IP address of your Algo server. If you find yourself regularly logging into the server then it will be useful to load your Algo ssh key automatically. Add the following snippet to the bottom of ~/.bash_profile
to add it to your shell environment permanently:
ssh-add ~/.ssh/algo > /dev/null 2>&1
Alternatively, you can choose to include the generated configuration for any Algo servers created into your SSH config. Edit the file ~/.ssh/config
to include this directive at the top:
Include <algodirectory>/configs/*/ssh_config
where <algodirectory>
is the directory where you cloned Algo.
Adding or Removing Users
If you chose to save the CA key during the deploy process, then Algo's own scripts can easily add and remove users from the VPN server.
- Update the
users
list in yourconfig.cfg
- Open a terminal,
cd
to the algo directory, and activate the virtual environment withsource .env/bin/activate
- Run the command:
./algo update-users
After this process completes, the Algo VPN server will contain only the users listed in the config.cfg
file.
Additional Documentation
- FAQ
- Troubleshooting
- How Algo uses Firewalls
Setup Instructions for Specific Cloud Providers
- Configure Amazon EC2
- Configure Azure
- Configure DigitalOcean
- Configure Google Cloud Platform
- Configure Vultr
- Configure CloudStack
- Configure Hetzner Cloud
Install and Deploy from Common Platforms
- Deploy from macOS
- Deploy from Windows
- Deploy from Google Cloud Shell
- Deploy from a Docker container
Setup VPN Clients to Connect to the Server
- Setup Windows clients
- Setup Android clients
- Setup Linux clients with Ansible
- Setup Ubuntu clients to use WireGuard
- Setup Linux clients to use IPsec
- Setup Apple devices to use IPsec
- Setup Macs running macOS 10.13 or older to use WireGuard
Advanced Deployment
- Deploy to your own Ubuntu server, and road warrior setup
- Deploy from Ansible non-interactively
- Deploy onto a cloud server at time of creation with shell script or cloud-init
- Deploy to an unsupported cloud provider
- Deploy to your own FreeBSD server
If you've read all the documentation and have further questions, create a new discussion.
Endorsements
I've been ranting about the sorry state of VPN svcs for so long, probably about time to give a proper talk on the subject. TL;DR: use Algo.
-- Kenn White
Before picking a VPN provider/app, make sure you do some research https://research.csiro.au/ng/wp-content/uploads/sites/106/2016/08/paper-1.pdf ... – or consider Algo
-- The Register
Algo is really easy and secure.
-- the grugq
I played around with Algo VPN, a set of scripts that let you set up a VPN in the cloud in very little time, even if you don’t know much about development. I’ve got to say that I was quite impressed with Trail of Bits’ approach.
-- Romain Dillet for TechCrunch
If you’re uncomfortable shelling out the cash to an anonymous, random VPN provider, this is the best solution.
-- Thorin Klosowski for Lifehacker
Support Algo VPN
All donations support continued development. Thanks!
- We accept donations via PayPal and Patreon.
- Use our referral code when you sign up to Digital Ocean for a $10 credit.
- We also accept and appreciate contributions of new code and bugfixes via Github Pull Requests.
Algo is licensed and distributed under the AGPLv3. If you want to distribute a closed-source modification or service based on Algo, then please consider purchasing an exception . As with the methods above, this will help support continued development.