openid and the new emailauth both assume that the user's authentication identity (how they log in) is suitable as an authorization identity (who they are when they have logged in). In particular, the OpenID or email address goes into the git history.

Relatedly, I'm not sure I'd be comfortable with enabling emailauth on my own sites while it writes users' email addresses into the git history: non-technical people (and many technical people for that matter) get possessive about who can know their email address. The usual expectation for email addresses on websites seems to be that they will be used by the site owner (and maybe their outsourced service providers), but not available to random third parties. The principle of least astonishment would suggest that we should do the same here.

This part is now addressed by cloaking email addresses: smcv@debian.orgsmcv@02f3eecb59311fc89970578832b63d57a071579e (that's the sha1sum of, as used in FOAF). --smcv

(The expectation of privacy for direct git commits is rather different: I think we can expect direct git committers to know that they should either set a plausible non-email-address in their git identity, like I used to use my OpenID, or have good spam filtering.)

If we present email-based users in the "web UI" using only the local-part of their address, we also have a potentially confusing situation where and both contribute to a wiki: if I'm reading the code right, they'd both be presented as chris, with no way to change that other than using a different email address?

Here is a sketch of a different account model that would address that:

  • An account has a username, e.g. smcv. It normally matches some regexp that includes neither @ nor / (to rule out collisions with email addresses and OpenIDs).

    • We currently allow qr{-[:alnum:]+/.:_} by default, so passwordauth accounts can in principle collide with OpenIDs. That would probably be worth fixing (for new account creation) anyway - I don't think we want users with / in their names, which would make their user-page into a subpage?

      I have fixed passwordauth to not let urls be registered. It seems this was not quite a security hole; it didn't let registering a username that already existed, so if an openid was an admin, as long as the user logged in using that openid, someone else couldn't come along and passwordauth collide with it. (Might be exploitable if you could guess an openid that was going to be added as an admin later though.) --Joey

  • If passwordauth is enabled, accounts may have a password. Users can authenticate to an account that has a password by entering that password. The username is always the account name (because there's little reason to do anything else).

  • If httpauth is enabled, anyone who can authenticate to the web server automatically gets access to the account of the same name in the wiki. (Or we could consider having a configurable map { web-server-level username => wiki account } but the default would be an identity mapping.)

  • If OpenID is enabled, accounts may have an OpenID. The owner of that OpenID can log in, and gets logged-in to that account. Either reusing the same OpenID for multiple accounts is not allowed, or if the same OpenID is attached to more than one account the user can choose (as an extra step). Optionally, more than one OpenID could be allowed.

  • If emailauth is enabled, accounts may have an email address. Users can authenticate to an account that has an email address (and is not a grandfathered OpenID) by using the token challenge. (passwordauth accounts could already do a password-reset, so this is not any less secure.)

  • Creating an account from an email address (maybe also OpenID?) has a new step: choosing a username, with some text about "this name will appear in recentchanges and in the wiki's history". The default would be the local-part (user) from the email address.

  • Grandfathered OpenID support: every existing account that looks like an OpenID has that OpenID associated with it, and it cannot be changed or removed. The displayed form is openiduser().

  • Grandfathered emailauth support, if required (but it might not be required if we implement this model before the next ikiwiki release): every existing account that looks like an email address has that email address associated with it, and it cannot be changed or removed. The displayed form is emailuser() but we should maybe change that to output something more like smcv@….

  • Hypothetically, an account could also have a https client certificate for a new client-certificate plugin, or a Google account for a new OAuth2 plugin, or whatever, and all of the above applies equally.

  • Unlike the current OpenID support, if the user's authentication provider goes away (or if Google stops doing OAuth2 and moves on to the next big thing), they can associate a different authentication identity with their existing wiki account, and continue.

This is basically the same model that Mozilla Persona encourages, except using emailauth ourselves instead of outsourcing (the equivalent of) that step to Mozilla.



I always find it a little ackward that i have two different accounts on this wiki: one for OpenID, and the other (regular account) for email notifications (because of notifyemail fails with some openid providers). It seems to me those accounts should just be merged as one, ie. I was expecting to be able to choose a username when i registered with openid.

Also, when you talk about "separating authentication from authorization", i immediately thought of ACL and Zoned ikiwiki, so i thought i could mention those... having stability in the usernames would help in the design of those... --anarcat

I'm not opposed to this, but I don't anticipate having resources to do any work on it either. (I do hope to obscure email addresses from git commits.) --Joey