SSL: ngx_ssl_set_client_hello_callback() error handling.

The function interface is changed to follow a common approach
to other functions used to setup SSL_CTX, with an exception of
"ngx_conf_t *cf" since it is not bound to nginx configuration.

This is required to report and propagate SSL_CTX_set_ex_data()
errors, as reminded by Coverity (CID 1668589).

src/event/ngx_event_openssl.c

@@ -1872,21 +1872,34 @@ ngx_ssl_new_client_session(ngx_ssl_conn_t *ssl_conn, ngx_ssl_session_t *sess)
 }
 
 
-void
-ngx_ssl_set_client_hello_callback(SSL_CTX *ssl_ctx,
-    ngx_ssl_client_hello_arg *cb)
+ngx_int_t
+ngx_ssl_set_client_hello_callback(ngx_ssl_t *ssl, ngx_ssl_client_hello_arg *cb)
 {
 #ifdef SSL_CLIENT_HELLO_SUCCESS
 
-    SSL_CTX_set_client_hello_cb(ssl_ctx, ngx_ssl_client_hello_callback, NULL);
-    SSL_CTX_set_ex_data(ssl_ctx, ngx_ssl_client_hello_arg_index, cb);
+    SSL_CTX_set_client_hello_cb(ssl->ctx, ngx_ssl_client_hello_callback, NULL);
+
+    if (SSL_CTX_set_ex_data(ssl->ctx, ngx_ssl_client_hello_arg_index, cb) == 0)
+    {
+        ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
+                      "SSL_CTX_set_ex_data() failed");
+        return NGX_ERROR;
+    }
 
 #elif defined OPENSSL_IS_BORINGSSL
 
     SSL_CTX_set_select_certificate_cb(ssl_ctx, ngx_ssl_select_certificate);
-    SSL_CTX_set_ex_data(ssl_ctx, ngx_ssl_client_hello_arg_index, cb);
+
+    if (SSL_CTX_set_ex_data(ssl->ctx, ngx_ssl_client_hello_arg_index, cb) == 0)
+    {
+        ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
+                      "SSL_CTX_set_ex_data() failed");
+        return NGX_ERROR;
+    }
 
 #endif
+
+    return NGX_OK;
 }
 
 

src/event/ngx_event_openssl.h

@@ -286,7 +286,7 @@ ngx_int_t ngx_ssl_session_ticket_keys(ngx_conf_t *cf, ngx_ssl_t *ssl,
     ngx_array_t *paths);
 ngx_int_t ngx_ssl_session_cache_init(ngx_shm_zone_t *shm_zone, void *data);
 
-void ngx_ssl_set_client_hello_callback(SSL_CTX *ssl_ctx,
+ngx_int_t ngx_ssl_set_client_hello_callback(ngx_ssl_t *ssl,
     ngx_ssl_client_hello_arg *cb);
 #ifdef SSL_CLIENT_HELLO_SUCCESS
 int ngx_ssl_client_hello_callback(ngx_ssl_conn_t *ssl_conn, int *ad, void *arg);

src/http/modules/ngx_http_ssl_module.c

@@ -758,7 +758,9 @@ ngx_http_ssl_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
     {
     static ngx_ssl_client_hello_arg cb = { ngx_http_ssl_servername };
 
-    ngx_ssl_set_client_hello_callback(conf->ssl.ctx, &cb);
+    if (ngx_ssl_set_client_hello_callback(&conf->ssl, &cb) != NGX_OK) {
+        return NGX_CONF_ERROR;
+    }
 
     if (SSL_CTX_set_tlsext_servername_callback(conf->ssl.ctx,
                                                ngx_http_ssl_servername)

src/stream/ngx_stream_ssl_module.c

@@ -1008,7 +1008,9 @@ ngx_stream_ssl_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
     {
     static ngx_ssl_client_hello_arg cb = { ngx_stream_ssl_servername };
 
-    ngx_ssl_set_client_hello_callback(conf->ssl.ctx, &cb);
+    if (ngx_ssl_set_client_hello_callback(&conf->ssl, &cb) != NGX_OK) {
+        return NGX_CONF_ERROR;
+    }
 
     SSL_CTX_set_tlsext_servername_callback(conf->ssl.ctx,
                                            ngx_stream_ssl_servername);