On 03/16/2017 06:52 AM, Heikki Linnakangas wrote: > On 03/14/2017 11:14 PM, Tom Lane wrote: >> In short, I don't think that argument refutes my position that "md5" >> in pg_hba.conf should be understood as allowing SCRAM passwords too. > > Yeah, let's do that. Here's a patch. > > I had some terminology trouble with the docs. What do you call a user > that has "md5XXXXX" in pgauthid.rolpassword? What about someone with a > SCRAM verifier? I used the terms "those users that have an MD5 hash set > in the system catalog", and "users that have set their password as a > SCRAM verifier", but it feels awkward.
maybe something like: "those users with an MD5 hashed password" "those users with a SCRAM verifier hash" > The behavior when a user doesn't exist, or doesn't have a valid > password, is a bit subtle. Previously, with 'md5' authentication, we > would send the client an MD5 challenge, and fail with "invalid password" > error after receiving the response. And with 'scram' authentication, we > would perform a dummy authentication exchange, with a made-up salt. This > is to avoid revealing to an unauthenticated client whether or not the > user existed. > > With this patch, the dummy authentication logic for 'md5' is a bit more > complicated. I made it look at the password_encryption GUC, and send the > client a dummy MD5 or SCRAM challenge based on that. The idea is that > most users presumably have a password of that type, so we use that > method for the dummy authentication, to make it look as "normal" as > possible. It's not perfect, if password_encryption is set to 'scram', > and you probe for a user that has an MD5 password set, you can tell that > it's a valid user from the fact that the server sends an MD5 challenge. Presumably if you are unauthenticated you don't have any way to know what password_encryption is set to, so this seems pretty reasonable. Joe -- Crunchy Data - http://crunchydata.com PostgreSQL Support for Secure Enterprises Consulting, Training, & Open Source Development
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