diff --git a/ngx_http_js_challenge.c b/ngx_http_js_challenge.c
index c5e67ad..5adf14d 100644
--- a/ngx_http_js_challenge.c
+++ b/ngx_http_js_challenge.c
@@ -174,8 +174,8 @@ static char *ngx_http_js_challenge_merge_loc_conf(ngx_conf_t *cf, void *parent,
         }
 
         conf->html = ngx_palloc(cf->pool, info.st_size);
-        memset(conf->html,'\0',info.st_size);
         int ret = read(fd, conf->html, info.st_size-1);
+        *(conf->html+ret) = '\0';
         close(fd);
         if (ret < 0) {
             ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "js_challenge_html: Could not read file '%s': %s", path,