fix #1332: allow ECDHE with all supported curves

with openssl 1.0.1, we had to limit ourself to one curve to
allow ECDHE at all.

with openssl 1.1.x, the same limit actually means only
allowing ECDSA certificates using that curve, even for
non-ephemeral ECDH handshakes, effectively only allowing
prime256 EC certificates.

since openssl 1.1.x supports auto-negotiation of the curve
used for ECDHE, simply use that for now.

Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>

diff --git a/PVE/APIServer/AnyEvent.pm b/PVE/APIServer/AnyEvent.pm
index f9970e64bcd4fe5fc1ace74ee057a5a4f824f3e6..222faab55e19aefcf1e46a26fd61ed0973c55457 100755 (executable)
--- a/PVE/APIServer/AnyEvent.pm
+++ b/PVE/APIServer/AnyEvent.pm
@@ -1616,15 +1616,7 @@ sub new {
 
     if ($self->{ssl}) {
        $self->{tls_ctx} = AnyEvent::TLS->new(%{$self->{ssl}});
-       # TODO : openssl >= 1.0.2 supports SSL_CTX_set_ecdh_auto to select a curve depending on
-       # server and client availability from SSL_CTX_set1_curves.
-       # that way other curves like 25519 can be used.
-       # openssl 1.0.1 can only support 1 curve at a time.
-       my $curve = Net::SSLeay::OBJ_txt2nid('prime256v1');
-       my $ecdh = Net::SSLeay::EC_KEY_new_by_curve_name($curve);
        Net::SSLeay::CTX_set_options($self->{tls_ctx}->{ctx}, &Net::SSLeay::OP_NO_COMPRESSION | &Net::SSLeay::OP_SINGLE_ECDH_USE | &Net::SSLeay::OP_SINGLE_DH_USE);
-       Net::SSLeay::CTX_set_tmp_ecdh($self->{tls_ctx}->{ctx}, $ecdh);
-       Net::SSLeay::EC_KEY_free($ecdh);
     }
 
     if ($self->{spiceproxy}) {