This adds a new settings, SOCIAL_AUTH_SUBDOMAIN, which specifies which
domain should be used for GitHub auth and other python-social-auth
backends.
If one is running a single-realm Zulip server like chat.zulip.org, one
doesn't need to use this setting, but for multi-realm servers using
social auth, this fixes an annoying bug where the session cookie that
python-social-auth sets early in the auth process on the root domain
ends up masking the session cookie that would have been used to
determine a user is logged in. The end result was that logging in
with GitHub on one domain on a multi-realm server like zulipchat.com
would appear to log you out from all the others!
We fix this by moving python-social-auth to a separate subdomain.
Fixes: #9847.
Disallow Realm.string_id's like "streams", "about", and several hundred
others. Also restrict string_id's to be at least 3 characters long, and only
use characters in [a-z0-9-].
Does not restrict realms created by the create_realm.py management command.
Aditya Bansal
Vishnu Ks
rht
James Rowan
Rishi Gupta
Robert Hönig