A minimal nginx
auth_request authentication service, based on cookies and htpasswd.
This little go tool can be used as an authentication service for
verifying that session cookies are valid and allowing users to log in
and have their data validated against
This means that if you run nginx and you have few users (and
few-enough sessions), you can run this service next to an actual
service you're running and have
htpasswd-login run a RESTful service
for authentication and even serve up a customizable authentication
Installation / running this
htpasswd-login requires a go modules to build, so a recent go
checkout is recommended - in CI, this tool builds with go 1.14.x.
go get -u github.com/antifuchs/htpasswd-login and you should
end up with a
htpasswd-login binary in your
Once installed, you can try out this service on the commandline like this (assuming
htpasswd-login --sessions /tmp/sessions --htpasswd example/htpasswd --secure=false --loginform=example/page
See example/README.md for details.
Once the login form looks like you think it should, deploy this to be visible to the big, bad internet. The following sections are (in order of importance) what you will definitely need to do:
In deployment (if you're running on HTTPS, which you
should), please run this with
--secure=true so that no cookies leak over insecure channels.
Configure a CSRF secret
htpasswd-login uses CSRF
to hopefully prevent some easy avenues for phishing from authenticated
sites. You should generate a CSRF secret and re-use this (otherwise
login forms served to clients will no longer be submittable if you
restart the server).
To generate a secret once, use
dd if=/dev/urandom bs=32 count=1 | openssl base64 > csrf-secret.b64
Then, to use that secret, pass the
flag to htpasswd-login.
Set up a cron job to clean out old sessions
Once this is working for you, make sure to run the tool with the same
arguments as you run the frontend with, and add
-cleanup in a cron
job once an hour or so, in order to clean out old sessions.
See the file auth_request.inc.conf
in examples for an example config. Note that in addition to including
this file in your
server blocks, you'll also have to have an
auth_request /auth stanza in every
location block you wish to
Limits & Operation
This tool is meant for personal use, and specifically constrains itself to some design choices that you shouldn't make when running this on a larger scale. Here are the assumptions I've made:
You don't have very many users. Credential lookup is O(n), which means that more users will make logins slow.
Each user doesn't have very many sessions. We store sessions in a directory, which means that as the total number of sessions grows into the many thousands, looking up those sessions will get slower (and may slow down your overall system).
You should run
-cleanupregularly, to remove old sessions.
You obviously have questions. I have reasons for building this. (And I would have loved not to have to build this!) Here goes:
Why not just use HTTP Basic authentication?
That's a good question: HTTP Basic authentication is quite simple, and if you can use it, you probably should!
However, Basic auth has some drawbacks:
Most browsers present a UI that isn't suitable for password managers
Some backend programs are not completely able to deal with living behind Basic auth: Some generate URLs that just don't work.
I think this tool combines the nicest advantages of HTTP Basic
authentication (namely, that you can use
.htpasswd files, which are
very well understood and easy to manipulate), with a nice and
accessible way for your users to log in.
As an accomodation for native apps that act as API clients, requests
bearing an HTTP Basic
Authorization header matching the credentials
.htpasswd file count as authenticated. So you can use Basic
authentication, however your users won't receive a login prompt.
Why not build authentication into a the thing you're running behind the scenes?
That mostly has to do with the amount of trust I'm willing to place in the backend program: If that has a preauth bug, there's a problem. (That said, if this program has a preauth bug, I would love to hear about it!)