SCRAM-SHA-1(-PLUS) + SCRAM-SHA-256(-PLUS) + SCRAM-SHA-512(-PLUS) + SCRAM-SHA3-512(-PLUS) supports

[Neustradamus]

Dear @notqmail team,

In first, I wish you a Happy New Year!

Can you add supports of :

• SCRAM-SHA-1
• SCRAM-SHA-1-PLUS
• SCRAM-SHA-256
• SCRAM-SHA-256-PLUS
• SCRAM-SHA-512
• SCRAM-SHA-512-PLUS
• SCRAM-SHA3-512
• SCRAM-SHA3-512-PLUS

"When using the SASL SCRAM mechanism, the SCRAM-SHA-256-PLUS variant SHOULD be preferred over the SCRAM-SHA-256 variant, and SHA-256 variants [RFC7677] SHOULD be preferred over SHA-1 variants [RFC5802]".

• SCRAM-SHA-1(-PLUS):
  -- https://tools.ietf.org/html/rfc5802
  -- https://tools.ietf.org/html/rfc6120

• SCRAM-SHA-256(-PLUS):
  -- https://tools.ietf.org/html/rfc7677 since 2015-11-02
  -- https://tools.ietf.org/html/rfc8600 since 2019-06-21: https://mailarchive.ietf.org/arch/msg/ietf-announce/suJMmeMhuAOmGn_PJYgX5Vm8lNA

• SCRAM-SHA-512(-PLUS):
  -- https://tools.ietf.org/html/draft-melnikov-scram-sha-512

• SCRAM-SHA3-512(-PLUS):
  -- https://tools.ietf.org/html/draft-melnikov-scram-sha3-512

https://xmpp.org/extensions/inbox/hash-recommendations.html

-PLUS variants:

• RFC5056: On the Use of Channel Bindings to Secure Channels: https://tools.ietf.org/html/rfc5056
• RFC5929: Channel Bindings for TLS: https://tools.ietf.org/html/rfc5929
• Channel-Binding Types: https://www.iana.org/assignments/channel-binding-types/channel-binding-types.xhtml
• RFC 9266: Channel Bindings for TLS 1.3: https://datatracker.ietf.org/doc/html/rfc9266

IMAP:

• RFC9051: Internet Message Access Protocol (IMAP) - Version 4rev2: https://tools.ietf.org/html/rfc9051

LDAP:

• RFC5803: Lightweight Directory Access Protocol (LDAP) Schema for Storing Salted: Challenge Response Authentication Mechanism (SCRAM) Secrets: https://tools.ietf.org/html/rfc5803

HTTP:

• RFC7804: Salted Challenge Response HTTP Authentication Mechanism: https://tools.ietf.org/html/rfc7804

2FA:

• Extensions to Salted Challenge Response (SCRAM) for 2 factor authentication: https://tools.ietf.org/html/draft-melnikov-scram-2fa

IANA:

• Simple Authentication and Security Layer (SASL) Mechanisms: https://www.iana.org/assignments/sasl-mechanisms/sasl-mechanisms.xhtml

Linked to:

• State of Play scram-sasl/info#1

[DerDakon]

Given that notqmail currently implements neither AUTH nor STARTTLS I don't think this really applies here. And in general I fail to see how this is relevant for SMTP, but that could be my fault.

[Neustradamus]

@DerDakon: It is good to do not support obsolete and unsecure CRAM-MD5 and DIGEST-MD5:

• https://datatracker.ietf.org/doc/html/rfc6331
• https://datatracker.ietf.org/doc/html/draft-zeilenga-luis140219-crammd5-to-historic-00

But SCRAM-SHA-* and SCRAM-SHA-*-PLUS (TLS Binding in more) are missing, the first part is a good start :)

[DerDakon]

Again: notqmail does not implement any of them at the given point. It does not offer any form of authentication, neither as client nor as server. These exist as external patches, some of them are imported to this repository in their own branches for the sole purpose of testing compatibility, but plain notqmail has nothing that uses them.

Should we ever end up doing them we could easily end up using some sort of external authentication provider for anything beyond LOGIN and PLAIN simply to avoid implementing such a thing again, which would then enable us also to choose something that includes SCRAM machanisms.