vg_load_svg: Prevent memory overflow for tag_name

Summary:
When copying tag_name, if length of referenced string is longer
than general case, it is not used as tag_name.

Test Plan: N/A

Reviewers: Hermet, smohanty

Reviewed By: Hermet

Subscribers: kimcinoo, herb, cedric, #committers, #reviewers

Tags: #efl

Differential Revision: https://phab.enlightenment.org/D12185

src/modules/evas/vg_loaders/svg/evas_vg_load_svg.c

@@ -2279,6 +2279,7 @@ _evas_svg_loader_xml_open_parser(Evas_SVG_Loader *loader,
         attrs_length = length - sz;
         while ((sz > 0) && (isspace(content[sz - 1])))
           sz--;
+        if ((unsigned int)sz > sizeof(tag_name)) return;
         strncpy(tag_name, content, sz);
         tag_name[sz] = '\0';
      }