@@ -4398,6 +4398,8 @@ NCP server (v2.4+) with "\-\-cipher BF\-CBC" and "\-\-ncp\-ciphers
AES\-256\-GCM:AES\-256\-CBC" set can either specify "\-\-cipher BF\-CBC" or
"\-\-cipher AES\-256\-CBC" and both will work.
+Note, for using NCP with a OpenVPN 2.4 server this list must include
+the AES\-256\-GCM and AES\-128\-GCM ciphers.
.\"*********************************************************
.TP
.B \-\-ncp\-disable
@@ -623,6 +623,7 @@ save_ncp_options(struct context *c)
c->c1.ciphername = c->options.ciphername;
c->c1.authname = c->options.authname;
c->c1.keysize = c->options.keysize;
+ c->c1.ncp_ciphers = c->options.ncp_ciphers;
}
/* Restores NCP-negotiable options to original values */
@@ -2827,6 +2828,7 @@ do_init_crypto_tls(struct context *c, const unsigned int flags)
to.tcp_mode = link_socket_proto_connection_oriented(options->ce.proto);
to.config_ciphername = c->c1.ciphername;
to.config_authname = c->c1.authname;
+ to.config_ncp_ciphers = c->c1.ncp_ciphers;
to.ncp_enabled = options->ncp_enabled;
to.transition_window = options->transition_window;
to.handshake_window = options->handshake_window;
@@ -4532,6 +4534,7 @@ inherit_context_child(struct context *dest,
dest->c1.ciphername = src->c1.ciphername;
dest->c1.authname = src->c1.authname;
dest->c1.keysize = src->c1.keysize;
+ dest->c1.ncp_ciphers = src->c1.ncp_ciphers;
/* inherit auth-token */
dest->c1.ks.auth_token_key = src->c1.ks.auth_token_key;
@@ -209,6 +209,7 @@ struct context_1
const char *ciphername; /**< Data channel cipher from config file */
const char *authname; /**< Data channel auth from config file */
+ const char *ncp_ciphers; /**< NCP Ciphers */
int keysize; /**< Data channel keysize from config file */
#endif
};
@@ -2322,7 +2322,9 @@ push_peer_info(struct buffer *buf, struct tls_session *session)
/* support for Negotiable Crypto Parameters */
if (session->opt->ncp_enabled
- && (session->opt->mode == MODE_SERVER || session->opt->pull))
+ && (session->opt->mode == MODE_SERVER || session->opt->pull)
+ && tls_item_in_cipher_list("AES-128-GCM", session->opt->config_ncp_ciphers)
+ && tls_item_in_cipher_list("AES-256-GCM", session->opt->config_ncp_ciphers))
{
buf_printf(&out, "IV_NCP=2\n");
}
@@ -290,6 +290,7 @@ struct tls_options
const char *config_ciphername;
const char *config_authname;
+ const char *config_ncp_ciphers;
bool ncp_enabled;
bool tls_crypt_v2;
We currently always announce IV_NCP=2 when we support these ciphers even when we do not accept them. This lead to a server pushing a AES-GCM-128 cipher to clients and the client then rejecting it. Patch V2: Remove unecessary restoring of ncp_ciphers Signed-off-by: Arne Schwabe <arne@rfc2549.org> --- doc/openvpn.8 | 2 ++ src/openvpn/init.c | 3 +++ src/openvpn/openvpn.h | 1 + src/openvpn/ssl.c | 4 +++- src/openvpn/ssl_common.h | 1 + 5 files changed, 10 insertions(+), 1 deletion(-)