Seeking FOSS user admin code

It must be a fairly standard wheel, so I'd rather not reinvent it.

Create/modify/delete users. Ditto their passwords & maybe enforce password change every X days. Also, create groups, like "sales", "support", etc and add/remove users.

The only unique part should be 开发者_StackOverflow中文版what they have permission to do (visit certain parts of the site after login, etc)

And I'd like to store admin data in an ODBC compliant database (MySql to start with, but I may move on).

Is this a new wheel?

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There doesn't seem to be much of anything on SourceForge, but if I could find something established and trusted I wouldn't even mind paying a few $100 as a trade of for the time needed to develop & test it.

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It's been done before, but the risk of obtaining it from an external source is to get and use something you don't truly understand, and possibly misuse it. That said, I did a search for just this sort of thing recently, and didn't find much of anything I particularly liked; I rolled my own, and now am happy because I do have full knowledge of exactly what the authentication is doing.