Hi folks, at first: thanks very much for the great piece of software!
I have a proposal to tighten the TLS security: enable the usage of a specific ec-curve in the 10-ssl.conf, e.g.
ssl_ec-curve = secp384r1Reason: I use a 384 bit EC server key, but dovecot uses "only" a prime256v1 curve.
Keygen was: f=dovecot; openssl ecparam -name secp384r1 -genkey -out $f.key openssl req -new -x509 -key $f.key -out ${f}.crt -days 2000 -sha512
Server check gives: prio ciphersuite protocols pfs curves 1 ECDHE-ECDSA-AES128-GCM-SHA256 TLSv1.2 ECDH,P-256,256bits prime256v1 2 ECDHE-ECDSA-AES128-SHA256 TLSv1.2 ECDH,P-256,256bits prime256v1 3 ECDHE-ECDSA-AES128-SHA TLSv1.2 ECDH,P-256,256bits prime256v1 4 ECDHE-ECDSA-AES256-GCM-SHA384 TLSv1.2 ECDH,P-256,256bits prime256v1 5 ECDHE-ECDSA-AES256-SHA384 TLSv1.2 ECDH,P-256,256bits prime256v1 6 ECDHE-ECDSA-AES256-SHA TLSv1.2 ECDH,P-256,256bits prime256v1
Certificate: UNTRUSTED, 384 bit, ecdsa-with-SHA512 signature
$ sudo nano /etc/dovecot/conf.d/10-ssl.conf ssl = required ssl_protocols = !SSlv2 !SSLv3 TLSv1.2 ssl_cipher_list = EECDH+AES128+AESGCM:EECDH+AES256+AESGCM:EECDH+AES128+SHA256:EECDH+AES256+SHA384:EECDH+AES128+SHA:EECDH+AES256+SHA ssl_prefer_server_ciphers = yes ssl_key =
OS is arch linux.
Thanks very much, Martin