ssl add server ecdh curve init

Using "real" SSL certs requires some init for openssl ECDH
curve.  Add a default curve "prime256v1" and allow overriding it
at context creation time.

Signed-off-by: Andy Green <andy.green@linaro.org>

diff --git a/lib/ssl.c b/lib/ssl.c
index 59a7425..ac3ad2e 100644 (file)
--- a/lib/ssl.c
+++ b/lib/ssl.c
@@ -24,6 +24,10 @@
  #include <openssl/err.h>
 #endif
 
+#if OPENSSL_VERSION_NUMBER >= 0x0090800fL
+#include <openssl/ecdh.h>
+#endif
+
 int openssl_websocket_private_data_index;
 
 static int
@@ -115,8 +119,8 @@ lws_context_ssl_init_ecdh(struct lws_context *context)
        KeyType = EVP_PKEY_type(pkey->type);
 
        if (EVP_PKEY_EC != KeyType) {
-               lwsl_err("Key type is not EC\n");
-               return 1;
+               lwsl_notice("Key type is not EC\n");
+               return 0;
        }
        /* Get the key */
        EC_key = EVP_PKEY_get1_EC_KEY(pkey);
@@ -131,6 +135,38 @@ lws_context_ssl_init_ecdh(struct lws_context *context)
        return 0;
 }
 
+static int
+lws_context_ssl_init_ecdh_curve(struct lws_context_creation_info *info,
+                               struct lws_context *context)
+{
+#if OPENSSL_VERSION_NUMBER >= 0x0090800fL
+       EC_KEY *ecdh;
+       int ecdh_nid;
+       const char *ecdh_curve = "prime256v1";
+
+       ecdh_nid = OBJ_sn2nid(ecdh_curve);
+       if (NID_undef == ecdh_nid) {
+               lwsl_err("SSL: Unknown curve name '%s'", ecdh_curve);
+               return 1;
+       }
+
+       ecdh = EC_KEY_new_by_curve_name(ecdh_nid);
+       if (NULL == ecdh) {
+               lwsl_err("SSL: Unable to create curve '%s'", ecdh_curve);
+               return 1;
+       }
+       SSL_CTX_set_tmp_ecdh(context->ssl_ctx, ecdh);
+       EC_KEY_free(ecdh);
+
+       SSL_CTX_set_options(context->ssl_ctx, SSL_OP_SINGLE_ECDH_USE);
+
+       lwsl_notice(" SSL ECDH curve '%s'\n", ecdh_curve);
+#else
+       lwsl_notice(" OpenSSL doesn't support ECDH\n");
+#endif
+       return 0;
+}
+
 LWS_VISIBLE int
 lws_context_init_server_ssl(struct lws_context_creation_info *info,
                            struct lws_context *context)
@@ -211,6 +247,7 @@ lws_context_init_server_ssl(struct lws_context_creation_info *info,
 #ifdef SSL_OP_NO_COMPRESSION
        SSL_CTX_set_options(context->ssl_ctx, SSL_OP_NO_COMPRESSION);
 #endif
+       SSL_CTX_set_options(context->ssl_ctx, SSL_OP_SINGLE_DH_USE);
        SSL_CTX_set_options(context->ssl_ctx, SSL_OP_CIPHER_SERVER_PREFERENCE);
        if (info->ssl_cipher_list)
                SSL_CTX_set_cipher_list(context->ssl_ctx,
@@ -231,16 +268,25 @@ lws_context_init_server_ssl(struct lws_context_creation_info *info,
 
                SSL_CTX_set_verify(context->ssl_ctx,
                       verify_options, OpenSSL_verify_callback);
+       }
 
-               /*
-                * give user code a chance to load certs into the server
-                * allowing it to verify incoming client certs
-                */
+       /*
+        * give user code a chance to load certs into the server
+        * allowing it to verify incoming client certs
+        */
 
-               context->protocols[0].callback(&wsi,
+       if (info->ssl_ca_filepath &&
+           !SSL_CTX_load_verify_locations(context->ssl_ctx,
+                                          info->ssl_ca_filepath, NULL)) {
+               lwsl_err("%s: SSL_CTX_load_verify_locations unhappy\n");
+       }
+
+       if (lws_context_ssl_init_ecdh_curve(info, context))
+               return -1;
+
+       context->protocols[0].callback(&wsi,
                        LWS_CALLBACK_OPENSSL_LOAD_EXTRA_SERVER_VERIFY_CERTS,
                                               context->ssl_ctx, NULL, 0);
-       }
 
        if (info->options & LWS_SERVER_OPTION_ALLOW_NON_SSL_ON_SSL_PORT)
                /* Normally SSL listener rejects non-ssl, optionally allow */
@@ -293,6 +339,13 @@ lws_context_init_server_ssl(struct lws_context_creation_info *info,
                if (lws_context_ssl_init_ecdh(context))
                        return 1;
 
+#if OPENSSL_VERSION_NUMBER >= 0x10200000L
+               n = SSL_CTX_build_cert_chain((SSL_CTX *)user,
+                                            SSL_BUILD_CHAIN_FLAG_CHECK |
+                                            SSL_BUILD_CHAIN_FLAG_IGNORE_ERROR);
+               lwsl_notice("%s: build cert chain %d", __func__, n);
+#endif
+
                /*
                 * SSL is happy and has a cert it's content with
                 * If we're supporting HTTP2, initialize that