Remove support for ACME v1 (#10194)

Fixes #9778

ACME v1 has been fully decommissioned for existing installs on June 1st 2021(see https://community.letsencrypt.org/t/end-of-life-plan-for-acmev1/88430/27), so we can now safely remove it from Synapse.

1 files changed, 0 insertions, 161 deletions

diff --git a/docs/ACME.md b/docs/ACME.md
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-# ACME
-
-From version 1.0 (June 2019) onwards, Synapse requires valid TLS
-certificates for communication between servers (by default on port
-`8448`) in addition to those that are client-facing (port `443`). To
-help homeserver admins fulfil this new requirement, Synapse v0.99.0
-introduced support for automatically provisioning certificates through 
-[Let's Encrypt](https://letsencrypt.org/) using the ACME protocol.
-
-## Deprecation of ACME v1
-
-In [March 2019](https://community.letsencrypt.org/t/end-of-life-plan-for-acmev1/88430),
-Let's Encrypt announced that they were deprecating version 1 of the ACME
-protocol, with the plan to disable the use of it for new accounts in
-November 2019, for new domains in June 2020, and for existing accounts and
-domains in June 2021.
-
-Synapse doesn't currently support version 2 of the ACME protocol, which
-means that:
-
-* for existing installs, Synapse's built-in ACME support will continue
-  to work until June 2021.
-* for new installs, this feature will not work at all.
-
-Either way, it is recommended to move from Synapse's ACME support
-feature to an external automated tool such as [certbot](https://github.com/certbot/certbot)
-(or browse [this list](https://letsencrypt.org/fr/docs/client-options/)
-for an alternative ACME client).
-
-It's also recommended to use a reverse proxy for the server-facing
-communications (more documentation about this can be found
-[here](/docs/reverse_proxy.md)) as well as the client-facing ones and
-have it serve the certificates.
-
-In case you can't do that and need Synapse to serve them itself, make
-sure to set the `tls_certificate_path` configuration setting to the path
-of the certificate (make sure to use the certificate containing the full
-certification chain, e.g. `fullchain.pem` if using certbot) and
-`tls_private_key_path` to the path of the matching private key. Note
-that in this case you will need to restart Synapse after each
-certificate renewal so that Synapse stops using the old certificate.
-
-If you still want to use Synapse's built-in ACME support, the rest of
-this document explains how to set it up. 
-
-## Initial setup 
-
-In the case that your `server_name` config variable is the same as
-the hostname that the client connects to, then the same certificate can be
-used between client and federation ports without issue.
-
-If your configuration file does not already have an `acme` section, you can
-generate an example config by running the `generate_config` executable. For
-example:
-
-```
-~/synapse/env3/bin/generate_config
-```
-
-You will need to provide Let's Encrypt (or another ACME provider) access to
-your Synapse ACME challenge responder on port 80, at the domain of your
-homeserver. This requires you to either change the port of the ACME listener
-provided by Synapse to a high port and reverse proxy to it, or use a tool
-like `authbind` to allow Synapse to listen on port 80 without root access.
-(Do not run Synapse with root permissions!) Detailed instructions are
-available under "ACME setup" below.
-
-If you already have certificates, you will need to back up or delete them
-(files `example.com.tls.crt` and `example.com.tls.key` in Synapse's root
-directory), Synapse's ACME implementation will not overwrite them.
-
-## ACME setup
-
-The main steps for enabling ACME support in short summary are:
-
-1. Allow Synapse to listen for incoming ACME challenges.
-1. Enable ACME support in `homeserver.yaml`.
-1. Move your old certificates (files `example.com.tls.crt` and `example.com.tls.key` out of the way if they currently exist at the paths specified in `homeserver.yaml`.
-1. Restart Synapse.
-
-Detailed instructions for each step are provided below.
-
-### Listening on port 80
-
-In order for Synapse to complete the ACME challenge to provision a
-certificate, it needs access to port 80. Typically listening on port 80 is
-only granted to applications running as root. There are thus two solutions to
-this problem.
-
-#### Using a reverse proxy
-
-A reverse proxy such as Apache or nginx allows a single process (the web
-server) to listen on port 80 and proxy traffic to the appropriate program
-running on your server. It is the recommended method for setting up ACME as
-it allows you to use your existing webserver while also allowing Synapse to
-provision certificates as needed.
-
-For nginx users, add the following line to your existing `server` block:
-
-```
-location /.well-known/acme-challenge {
-    proxy_pass http://localhost:8009;
-}
-```
-
-For Apache, add the following to your existing webserver config:
-
-```
-ProxyPass /.well-known/acme-challenge http://localhost:8009/.well-known/acme-challenge
-```
-
-Make sure to restart/reload your webserver after making changes.
-
-Now make the relevant changes in `homeserver.yaml` to enable ACME support:
-
-```
-acme:
-    enabled: true
-    port: 8009
-```
-
-#### Authbind
-
-`authbind` allows a program which does not run as root to bind to
-low-numbered ports in a controlled way. The setup is simpler, but requires a
-webserver not to already be running on port 80. **This includes every time
-Synapse renews a certificate**, which may be cumbersome if you usually run a
-web server on port 80. Nevertheless, if you're sure port 80 is not being used
-for any other purpose then all that is necessary is the following:
-
-Install `authbind`. For example, on Debian/Ubuntu:
-
-```
-sudo apt-get install authbind
-```
-
-Allow `authbind` to bind port 80:
-
-```
-sudo touch /etc/authbind/byport/80
-sudo chmod 777 /etc/authbind/byport/80
-```
-
-When Synapse is started, use the following syntax:
-
-```
-authbind --deep <synapse start command>
-```
-
-Make the relevant changes in `homeserver.yaml` to enable ACME support:
-
-```
-acme:
-    enabled: true
-```
-
-### (Re)starting synapse
-
-Ensure that the certificate paths specified in `homeserver.yaml` (`tls_certificate_path` and `tls_private_key_path`) do not currently point to any files. Synapse will not provision certificates if files exist, as it does not want to overwrite existing certificates.
-
-Finally, start/restart Synapse.