On Mon, Aug 26, 2024 at 11:20:52AM +1000, Viktor Dukhovni wrote:
> > and, I publish both RSA and ECDSA DANE records.
>
> If you also have both certificate algorithms deployed live on your
> server keep in mind that you then need two sets of "3 1 1" records,
> one for each algorithm:
>
> https://mail.sys4.de/pipermail/dane-users/2017-August/000416.html
I see that you've indeed published "3 1 2" records for both your RSA and
your ECDSA certificate. This is in my view an "expert" configuration.
Make sure you have monitoring in place on your end to catch any problems
that might occur around future certificate renewals.
Note also that the "ISRG X1" or "ISRG X2" root CA cert (whichever is the
issuer of your intermediate CA cert) is not included in your server
certificate chain file, so the TLSA records for these won't work with
at least the DANE TLSA code in Postfix and Exim and likely other MTAs.
_25._tcp.mx2-edge.censored.net. IN TLSA 2 1 1
025490860b498ab73c6a12f27a49ad5fe230fafe3ac8f6112c9b7d0aad46941d
_25._tcp.mx2-edge.censored.net. IN TLSA 2 1 1
0b9fa5a59eed715c26c1020c711b4f6ec42d58b0015e14337a39dad301c5afc3
_25._tcp.mx2-edge.censored.net. IN TLSA 2 1 1
2bbad93ab5c79279ec121507f272cbe0c6647a3aae52e22f388afab426b4adba
_25._tcp.mx2-edge.censored.net. IN TLSA 2 1 1
3586d4ecf070578cbd27aedce20b964e48bc149faeb9dad72f46b857869172b8
_25._tcp.mx2-edge.censored.net. IN TLSA 2 1 1
6ddac18698f7f1f7e1c69b9bce420d974ac6f94ca8b2c761701623f99c767dc7
_25._tcp.mx2-edge.censored.net. IN TLSA 2 1 1
762195c225586ee6c0237456e2107dc54f1efc21f61a792ebd515913cce68332
_25._tcp.mx2-edge.censored.net. IN TLSA 2 1 1
885bf0572252c6741dc9a52f5044487fef2a93b811cdedfad7624cc283b7cdd5
_25._tcp.mx2-edge.censored.net. IN TLSA 2 1 1
919c0df7a787b597ed056ace654b1de9c0387acf349f73734a4fd7b58cf612a4
_25._tcp.mx2-edge.censored.net. IN TLSA 2 1 1
cbbc559b44d524d6a132bdac672744da3407f12aae5d5f722c5f6c7913871c75
_25._tcp.mx2-edge.censored.net. IN TLSA 2 1 1
d016e1fe311948aca64f2de44ce86c9a51ca041df6103bb52a88eb3f761f57d7
_25._tcp.mx2-edge.censored.net. IN TLSA 2 1 1
f1440a9b76e1e41e53a4cb461329bf6337b419726be513e42e19f1c691c5d4b2
_25._tcp.mx2-edge.censored.net. IN TLSA 2 1 1
f1647a5ee3efac54c892e930584fe47979b7acd1c76c1271bca1c5076d869888
_25._tcp.mx2-edge.censored.net. IN TLSA 3 1 2
1b1436e45b1d56e4183f45d81f0fff48ea193aeda60d99b037945cc1d20fbfecd3da2b5d5de75fdfe0cf0420891d649957568c0cb8dc7cdae83ff4d21ac4e3fa
_25._tcp.mx2-edge.censored.net. IN TLSA 3 1 2
eec904205869cafa231f037b958e3ce7cde10443464261b01f5b95d852dd50cdefee7cead8b79792dca7fb1ea4f138fc615d1a2018133fc2d94d1260e012bf5a
mx2-edge.censored.net[192.0.2.1]: pass: TLSA match: depth = 0, name =
mx2-edge.censored.net
TLS = TLS13 with CHACHA20POLY1305-SHA256,X25519,PubKeyALG_EC
name = mx1-edge.censored.net
name = mx2-edge.censored.net
depth = 0
Issuer CommonName = E6
Issuer Organization = Let's Encrypt
notBefore = 2024-08-25T15:51:37Z
notAfter = 2024-11-23T15:51:36Z
Subject CommonName = mx1-edge.censored.net
pkey sha512 [matched] <- 3 1 2
eec904205869cafa231f037b958e3ce7cde10443464261b01f5b95d852dd50cdefee7cead8b79792dca7fb1ea4f138fc615d1a2018133fc2d94d1260e012bf5a
depth = 1
Issuer CommonName = ISRG Root X2
Issuer Organization = Internet Security Research Group
notBefore = 2024-03-13T00:00:00Z
notAfter = 2027-03-12T23:59:59Z
Subject CommonName = E6
Subject Organization = Let's Encrypt
pkey sha256 [matched] <- 2 1 1
d016e1fe311948aca64f2de44ce86c9a51ca041df6103bb52a88eb3f761f57d7
--
Viktor.
P.S.
The DANE survey cannot detect any problems with your RSA certificate,
because your servers choose ECDSA even when the client prefers RSA, and
the survey engine only rotates its RSA/ECDSA preference between tests,
but does not do multiple probes limiting the supported algorithms to one
or the other. So you're on your own for testing that RSA still works.
My "danesmtp" bash function can probe specific signature algorithms:
https://list.sys4.de/hyperkitty/list/[email protected]/thread/NKDBQABSTAAWLTHSZKC7P3HALF7VE5QY/
$
rsa="rsa_pss_rsae_sha256:rsa_pss_rsae_sha384:rsa_pss_rsae_sha512:rsa_pss_pss_sha256:rsa_pss_pss_sha384:rsa_pss_pss_sha512:rsa_pkcs1_sha256:rsa_pkcs1_sha384:rsa_pkcs1_sha512"
$
ecdsa="ecdsa_secp256r1_sha256:ecdsa_secp384r1_sha384:ecdsa_secp521r1_sha512"
$ danesmtp mx2-edge.censored.net -sigalgs "$ecdsa"
CONNECTION ESTABLISHED
Protocol version: TLSv1.3
Ciphersuite: TLS_CHACHA20_POLY1305_SHA256
Peer certificate: CN = mx1-edge.censored.net
Hash used: SHA384
Signature type: ECDSA
Verification: OK
DANE TLSA 3 1 2 ...18133fc2d94d1260e012bf5a matched EE certificate at depth 0
Server Temp Key: X25519, 253 bits
250 SMTPUTF8
DONE
$ danesmtp mx2-edge.censored.net -sigalgs "$rsa"
CONNECTION ESTABLISHED
Protocol version: TLSv1.3
Ciphersuite: TLS_CHACHA20_POLY1305_SHA256
Peer certificate: CN = mx1-edge.censored.net
Hash used: SHA256
Signature type: RSA-PSS
Verification: OK
DANE TLSA 3 1 2 ...b8dc7cdae83ff4d21ac4e3fa matched EE certificate at depth 0
Server Temp Key: X25519, 253 bits
250 SMTPUTF8
DONE
The exit status was 0 in both cases, indicating success.
Further tweaks are needed to the code to test whether *specific* TLSA
records (e.g. the ones intended to match the root CAs) are effective,
you'd need to trim or override the TLSA records passed by the function
to "s_client".
