[gimp/gimp-2-8] Bug 790784 - (CVE-2017-17784) heap overread in gbr parser / load_image.

[Jehan Pagès <jehanp src gnome org>]

commit c57f9dcf1934a9ab0cd67650f2dea18cb0902270
Author: Jehan <jehan girinstud io>
Date:   Thu Dec 21 12:25:32 2017 +0100

    Bug 790784 - (CVE-2017-17784) heap overread in gbr parser / load_image.
    
    We were assuming the input name was well formed, hence was
    nul-terminated. As any data coming from external input, this has to be
    thorougly checked.
    Similar to commit 06d24a79af94837d615d0024916bb95a01bf3c59 but adapted
    to older gimp-2-8 code.

 plug-ins/common/file-gbr.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/plug-ins/common/file-gbr.c b/plug-ins/common/file-gbr.c
index b028100..d3f01d9 100644
--- a/plug-ins/common/file-gbr.c
+++ b/plug-ins/common/file-gbr.c
@@ -443,7 +443,8 @@ load_image (const gchar  *filename,
     {
       gchar *temp = g_new (gchar, bn_size);
 
-      if ((read (fd, temp, bn_size)) < bn_size)
+      if ((read (fd, temp, bn_size)) < bn_size ||
+          temp[bn_size - 1] != '\0')
         {
           g_set_error (error, G_FILE_ERROR, G_FILE_ERROR_FAILED,
                        _("Error in GIMP brush file '%s'"),