maciej łebkowski
Maciej Łebkowski

Configuring SVN via SSH using public keys

in Professional

The process of configuring SVN over SSH using private/public key pairs is quite complicated, especially on Windows platform — I couldn’t find a robust instruction on the net, so I’m writing my own. The key principles:

  • SVN repository without HTTP/snvserve access, only SSH
  • Single svn system user on the server
  • Windows client

Step 0: required software

Tortoise SVN is the best SVN client ever made, so I’m sticking to that. PuTTY won’t be used per se, but it’s required for the configuration.

Step 1: generate the key

Run PuTTYgen to generate a private/public key pair. Just use the defaults and enter a blank passphrase (convinience over security, it’s your call).

using PuTTYgen

Just follow the on-screen instructions. Save the generated private key, the public key won’t be needed. Just copy the „paste ready” version — this will be used for the server configuration.

Step 2: configure the connection

You will not need to connect using PuTTY, you will however need to define a new session using it.

Open PuTTY and enter URL in the form username@hostname. Remember, that it’s not your username — it’s the system user used for SVN (see server configuration below).

basic PuTTY configuration

Next select the Connection / SSH / Auth section and use the private key saved in step one.

selecting private key

The last part — this is important — go back to the first screen (Session), name the session and hit „Save”. This way the configuration will be saved to Windows Registry, so that Tortoise can retrieve it later.

save the PuTTY session

Step 3: checkout using Tortoise

You’re ready to go. You can checkout the repo using URL in form svn+ssh://session-name/repo-name

checkout from repository

Linux client setup

In case you’re trying to do the same on a Linux client, the process is far more simple.

  1. Generate the needed pub/priv keys

    $ ssh_keygen -q -t rsa

    Save the key in /nassau_rsa. You can as well use your other rsa key, but let’s not mix things up.

  2. Configure the connection in /config:

    Host nassau
    User svn
    IdentityFile ~/.ssh/nassau_rsa

    The User is the system username used for SVN over SSH connections.

  3. Send the public key to sysadmin or configure the authorized_keys yourself.

You can now access your repository via url:

$ svn info svn+ssh://nassau/lt
Path: lt
URL: svn+ssh://nassau/lt
Repository Root: svn+ssh://nassau/lt
Repository UUID: 4d67b713-58a8-4edb-9e91-d78eb345f821

Configure the server

Do some basic setup. Create user, your repository, etc.

useradd -d /home/svn -m -s /bin/bash svn
su svn
svnadmin create lt

Create authorized_keys:

mkdir .ssh
touch .ssh/authorized_keys
chmod 0700 .ssh
chmod 0600 .ssh/authorized_keys

Add user public keys prefixed with line:

command="svnserve -t -r /home/svn --tunnel-user=puck",no-port-forwarding,no-agent-forwarding,no-X11-forwarding,no-pty

Please note:

  • replace --tunnel-user value with username associated with the key — this will apear as the commit user
  • other options are optional, but ensure that the SSH connection is not abused

Example authorized_keys file (newlines created for readability):

command="svnserve -t -r /home/svn --tunnel-user=maciej",no-port-forwarding,no-ag
ent-forwarding,no-X11-forwarding,no-pty ssh-rsa AAAAB3NzaC1yc2EAAAABJQAAAIEAnrS7
ycN2hE8= rsa-key-20110809

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About the author

My name is Maciej Łebkowski. I’m a full stack software engineer, a writer, a leader, and I play board games in my spare time. I’m currently in charge of the technical side of a new project called Docplanner Phone.

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This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License. This means that you may use it for commercial purposes, adapt upon it, but you need to release it under the same license. In any case you must give credit to the original author of the work (Maciej Łebkowski), including a URI to the work.