Viktor Dukhovni via Postfix-users wrote in
<[email protected]>:
|On Fri, Mar 01, 2024 at 12:26:33AM +0100, Steffen Nurpmeso wrote:
|
|> i still use the
|>
|> # super modern, forward secrecy TLSv1.2 / TLSv1.3 selection..
|> tls_high_cipherlist = EECDH+AESGCM:EECDH+AES256:EDH+AESGCM:CHACHA20
|
|I don't recommend cargo-culting random cipher lists.
Well i think he carefully selected that; i must admit i have
blindly said that, somewhen on this list i posted "the same" thing
and by then i still knew what was his and what i added or changed.
|> smtpd_tls_mandatory_ciphers = high
|> smtpd_tls_mandatory_exclude_ciphers = TLSv1
|
|In pratice, this boils down to
|
| ECDHE-ECDSA-AES256-SHA TLSv1 Kx=ECDH Au=ECDSA Enc=AES(256) \
| Mac=SHA1
| ECDHE-RSA-AES256-SHA TLSv1 Kx=ECDH Au=RSA Enc=AES(256) \
| Mac=SHA1
| ECDHE-ECDSA-AES128-SHA TLSv1 Kx=ECDH Au=ECDSA Enc=AES(128) \
| Mac=SHA1
| ECDHE-RSA-AES128-SHA TLSv1 Kx=ECDH Au=RSA Enc=AES(128) \
| Mac=SHA1
|
|Which should all be fine (better than cleartext) for email.
You are the specialist who can even write RFCs on this topic, dear
Viktor Dukhovni. Ie TLS. And regarding cryptographics aka its
maths i have zero competence. In reality, and myself, that is.
If you say the above TLSv1 things are ok, so it may be, but
i would hope my above config boils down to the below, because
otherwise i would even have misunderstood postconf(5).
$ openssl ciphers -v EECDH+AESGCM:EECDH+AES256:EDH+AESGCM:CHACHA20:!TLSv1
TLS_AES_256_GCM_SHA384 TLSv1.3 Kx=any Au=any Enc=AESGCM(256)
Mac=AEAD
TLS_CHACHA20_POLY1305_SHA256 TLSv1.3 Kx=any Au=any
Enc=CHACHA20/POLY1305(256) Mac=AEAD
TLS_AES_128_GCM_SHA256 TLSv1.3 Kx=any Au=any Enc=AESGCM(128)
Mac=AEAD
ECDHE-ECDSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH Au=ECDSA Enc=AESGCM(256)
Mac=AEAD
ECDHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH Au=RSA Enc=AESGCM(256)
Mac=AEAD
ECDHE-ECDSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH Au=ECDSA Enc=AESGCM(128)
Mac=AEAD
ECDHE-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH Au=RSA Enc=AESGCM(128)
Mac=AEAD
ECDHE-ECDSA-AES256-CCM TLSv1.2 Kx=ECDH Au=ECDSA Enc=AESCCM(256)
Mac=AEAD
ECDHE-ECDSA-AES256-CCM8 TLSv1.2 Kx=ECDH Au=ECDSA Enc=AESCCM8(256)
Mac=AEAD
ECDHE-ECDSA-AES256-SHA384 TLSv1.2 Kx=ECDH Au=ECDSA Enc=AES(256)
Mac=SHA384
ECDHE-RSA-AES256-SHA384 TLSv1.2 Kx=ECDH Au=RSA Enc=AES(256)
Mac=SHA384
DHE-DSS-AES256-GCM-SHA384 TLSv1.2 Kx=DH Au=DSS Enc=AESGCM(256)
Mac=AEAD
DHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=DH Au=RSA Enc=AESGCM(256)
Mac=AEAD
DHE-DSS-AES128-GCM-SHA256 TLSv1.2 Kx=DH Au=DSS Enc=AESGCM(128)
Mac=AEAD
DHE-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=DH Au=RSA Enc=AESGCM(128)
Mac=AEAD
ECDHE-ECDSA-CHACHA20-POLY1305 TLSv1.2 Kx=ECDH Au=ECDSA
Enc=CHACHA20/POLY1305(256) Mac=AEAD
ECDHE-RSA-CHACHA20-POLY1305 TLSv1.2 Kx=ECDH Au=RSA
Enc=CHACHA20/POLY1305(256) Mac=AEAD
DHE-RSA-CHACHA20-POLY1305 TLSv1.2 Kx=DH Au=RSA
Enc=CHACHA20/POLY1305(256) Mac=AEAD
RSA-PSK-CHACHA20-POLY1305 TLSv1.2 Kx=RSAPSK Au=RSA
Enc=CHACHA20/POLY1305(256) Mac=AEAD
DHE-PSK-CHACHA20-POLY1305 TLSv1.2 Kx=DHEPSK Au=PSK
Enc=CHACHA20/POLY1305(256) Mac=AEAD
ECDHE-PSK-CHACHA20-POLY1305 TLSv1.2 Kx=ECDHEPSK Au=PSK
Enc=CHACHA20/POLY1305(256) Mac=AEAD
PSK-CHACHA20-POLY1305 TLSv1.2 Kx=PSK Au=PSK
Enc=CHACHA20/POLY1305(256) Mac=AEAD
I also admit i do not understand your "compaigning for anon
ciphers for SMTP". I think the TLS system should move away from
CA pools, to some DNS based thing. Your DANE is standardized and
you hear the word often, i am currently enthusiastic on how
pragmatic DKIM solved its problems, and that includes the DNS
record holding the certificate (aka public key, here). I would
have no problem (except for the sheer record size, but of course,
like DANE, a simple fingerprint could also be published, this is
sufficient!) with a simple TLSXXX record, as long as DNS can now
be used over secure transport itself, and DNSSEC is also simple
and simply available. 'Still hoping for my provider to add it,
now. For S/MIME it would have to provide the complete key,
however. Ie, very simple and pragmatic, with decades old OpenSSL
functions to simply load PEM key data in, and you are ready to go.
--steffen
|
|Der Kragenbaer, The moon bear,
|der holt sich munter he cheerfully and one by one
|einen nach dem anderen runter wa.ks himself off
|(By Robert Gernhardt)
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