"register user" admin api is incorrectly blocked if the MAU limit has been reached

[Twi1ightSparkle]

Description

If the server has a MAU user limit, you can add unlimited users accounts. But you cannot add accounts if MAU is rached

Steps to reproduce

• reach mau limit
• add new user account

Version information

v1.12.0

• Homeserver:

If not matrix.org: At least all Modular servers

Container

[anoadragon453]

It's expected that a normal user cannot register, however it's likely not expected that one cannot register new users through the Admin API.

If we want to make that change, check_auth_blocking should probably not be run here if the call is coming through the Admin API:

synapse/synapse/handlers/register.py

Line 166 in 326c893

yield self.auth.check_auth_blocking(threepid=threepid)

[dklimpel]

Is it a solution to test if address is null?
Like here:

synapse/synapse/handlers/register.py

Line 164 in 326c893

yield self.check_registration_ratelimit(address)

synapse/synapse/handlers/register.py

Lines 420 to 432 in 9bae740

	def check_registration_ratelimit(self, address):
	"""A simple helper method to check whether the registration rate limit has been hit
	for a given IP address
	Args:
	address (str|None): the IP address used to perform the registration. If this is
	None, no ratelimiting will be performed.
	Raises:
	LimitExceededError: If the rate limit has been exceeded.
	"""
	if not address:
	return

The call from admin API has no address.

[richvdh]

there's some debate on what is the right wait to fix this inconsistency...

[richvdh]

ok, sounds like we're agreed that the MAU limit should not apply to the admin api.