How to set up a git server over HTTP (s)¶

• Table of contents
• How to set up a git server over HTTP (s)
  • Step 1: Permissions, permissions and more permissions!
  • Step 2: Dependencies and Modules
  • Step 3: Bare Minimum Config for specific repos
  • Step 4: Adding automatic repo discovery
  • Step 5: Adding Authentication through HTTP
  • Step 6: Only allowing secure HTTPS connections
  • References

One may have already set up a git server; it's as easy as enabling ssh on a NIX machine.
*But one may have encountered the not-so-usual situation where you're on a random network and you can't access port 22!
This is a guide on how to set up a git over HTTPS server using the git Smart-HTTP protocol.

Step 1: Permissions, permissions and more permissions!¶

See: FAQ: Why do I get 403 Forbidden?

Permissions are very important! Remember that git will be performing reads and writes to directories and files! Be sure to set up your user and group correctly. You may have to chmod and chown your git repo in order for it to be accessible to user/group under which the lighttpd server runs. lighttpd runs CGI programs (e.g. git) under the user/group that lighttpd runs. (Additional configuration with helper programs -- such as execwrap or suEXEC -- can change that, but doing so is not discussed further here).

Step 2: Dependencies and Modules¶

For system dependencies, you will require (of course)
- git (make sure you have the /usr/lib/git-core/git-http-backend binary, this should be installed by default with the git package on Arch Linux)

For lighttpd modules, you will require:
- mod_cgi
- mod_alias
- mod_setenv
- mod_auth (optional) with mod_authn_file.

Step 3: Bare Minimum Config for specific repos¶

You must use a subdomain or another domain altogether , else the CGI script will get confused and won't be able to read the paths correctly.

The bare minimum to get the CGI git-http-backend script working is:
- set the environment variable GIT_PROJECT_ROOT to the parent directory of one of your git repositories.
- create a git-daemon-export-ok file inside each git repo you'd like to make accessible.

server.modules += ("mod_setenv", "mod_cgi", "mod_alias")

$HTTP["host"] == "git-test.yourdomain.com" {
    alias.url = ( "" => "/usr/lib/git-core/git-http-backend" )
    setenv.set-environment = ( "GIT_PROJECT_ROOT" => "/var/www/git/" )
    cgi.assign = ( "" => "" )
}

the code above assumes:
- your domain git-test.yourdomain.com is only used for this CGI script.
- /var/www/git/ is a directory with bare git repositories inside them.
- and each repository (server-side) has a git-daemon-export-ok file inside it.

Step 4: Adding automatic repo discovery¶

Ok, you've got a basic config working. Now you'd like some kind of automatic discovery so that you don't have to manually add each git repo. One can do this by setting the environment variable GIT_HTTP_EXPORT_ALL. Remember that you should use the += operator when wanting to append variables. See mod_setenv

setenv.set-environment += ( "GIT_HTTP_EXPORT_ALL" => "" )

Great! Now you can clone any repo under /var/www/git/.

Step 5: Adding Authentication through HTTP¶

According to the git Smart-HTTP docs, git itself does not implement any kind of security. That is the job of the web server, in our case, lighttpd. We can implement security by adding HTTP authentication. Refer to mod_auth. The following would allow only authenticated users to clone from and push to repositories:

# using mod auth with plain text module mod_authn_file
server.modules += ("mod_auth", "mod_authn_file")
server.modules += ("mod_setenv", "mod_cgi", "mod_alias")

$HTTP["host"] == "git-test.yourdomain.com" {
    # password file is at /home/www-data/user-info
    # example plain-text password file:
    #   agent007:secret
    auth.backend = "plain" 
    auth.backend.plain.userfile = "/home/www-data/user-info" 

    # this must be set to require auth under this domain.
    auth.require = ( "" => ("method" => "basic", "realm" => "example", "require" => "valid-user") )

    alias.url = ( "" => "/usr/lib/git-core/git-http-backend" )

    setenv.set-environment = ( "GIT_PROJECT_ROOT" => "/var/www/git/" )
    setenv.set-environment += ( "GIT_HTTP_EXPORT_ALL" => "" )

    cgi.assign = ( "" => "" )
}

Step 6: Only allowing secure HTTPS connections¶

This is easy. Just configure https as normal for your subdomain. Then, wrap the code around an $HTTP["scheme"] == "http" conditional and use mod_redirect to redirect http requests to https, creating the final config:

# git server over HTTPS configuration for lighttpd
# author: trevcan
# github.com/trevcan/

server.modules += ("mod_openssl")
$SERVER["socket"] == ":443" {
    ssl.engine  = "enable" 
    ssl.privkey = "/etc/keys/yourdomain.com/privkey.pem" 
    ssl.pemfile = "/etc/keys/yourdomain.com/fullchain.pem" 
}

# log CGI stderr to separate log
server.breakagelog = "/var/log/lighttpd/breakage.log" 

# using mod auth with plain text module mod_authhn_file
server.modules += ("mod_auth", "mod_authn_file")
server.modules += ("mod_redirect", "mod_setenv", "mod_cgi", "mod_alias")

$HTTP["host"] == "git-test.yourdomain.com" {
    ssl.privkey = "/etc/keys/git-test.yourdomain.com/privkey.pem" 
    ssl.pemfile = "/etc/keys/git-test.yourdomain.com/fullchain.pem" 

    $HTTP["scheme"] == "http" {
        url.redirect = ("" => "https://${url.authority}${url.path}${qsa}")
        #url.redirect-code = 308  # (before lighttpd 1.4.75)
    } else {
        # password file is at /home/www-data/user-info
        # example plain-text password file:
        #   agent007:secret
        auth.backend = "plain" 
        auth.backend.plain.userfile = "/home/www-data/user-info" 

        # this must be set to require auth under this domain.
        auth.require = ( "" => ("method" => "basic", "realm" => "example", "require" => "valid-user") )
    }

    alias.url = ( "" => "/usr/lib/git-core/git-http-backend" )

    setenv.set-environment = ( "GIT_PROJECT_ROOT" => "/var/www/git/" )
    setenv.set-environment += ( "GIT_HTTP_EXPORT_ALL" => "" )

    cgi.assign = ( "" => "" )
}

References¶

- Smart HTTP git documentation.
- Lighttpd Docs Mod Auth
- Lighttpd Docs Mod CGI
- Lighttpd Docs Mod SetEnv
- Lighttpd Docs Mod Alias
- Lighttpd Docs Mod Redirect
- Lighttpd Docs TLS/SSL