[gdk-pixbuf] Revert "pixdata: Prevent buffer overflow by checking for bounds before memcpy"

[Bastien Nocera <hadess src gnome org>]

commit 6ddb1600e28d283ef953fd647bb5e3eca284bc69
Author: Bastien Nocera <hadess hadess net>
Date:   Fri Dec 16 13:57:35 2016 +0100

    Revert "pixdata: Prevent buffer overflow by checking for bounds before memcpy"
    
    The fix is incorrect.
    
    This reverts commit 9ae4723ec3fa631354e3d201c5435a7385c33d45.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=775693

 gdk-pixbuf/gdk-pixdata.c |   19 +------------------
 1 files changed, 1 insertions(+), 18 deletions(-)
---
diff --git a/gdk-pixbuf/gdk-pixdata.c b/gdk-pixbuf/gdk-pixdata.c
index 5cf485c..b026f7d 100644
--- a/gdk-pixbuf/gdk-pixdata.c
+++ b/gdk-pixbuf/gdk-pixdata.c
@@ -430,7 +430,6 @@ gdk_pixbuf_from_pixdata (const GdkPixdata *pixdata,
 {
   guint encoding, bpp;
   guint8 *data = NULL;
-  guint8 *data_limit = NULL;
 
   g_return_val_if_fail (pixdata != NULL, NULL);
   g_return_val_if_fail (pixdata->width > 0, NULL);
@@ -457,9 +456,6 @@ gdk_pixbuf_from_pixdata (const GdkPixdata *pixdata,
   if (copy_pixels)
     {
       data = g_try_malloc_n (pixdata->height, pixdata->rowstride);
-      /* If this calculation overflows, data is NULL */
-      const size_t data_size = pixdata->height * pixdata->rowstride;
-      data_limit = data + data_size;
       if (!data)
        {
          g_set_error (error, GDK_PIXBUF_ERROR,
@@ -526,20 +522,7 @@ gdk_pixbuf_from_pixdata (const GdkPixdata *pixdata,
        }
     }
   else if (copy_pixels)
-    {
-      if (data + (pixdata->rowstride * pixdata->height) < data_limit)
-        {
-          memcpy (data, pixdata->pixel_data, pixdata->rowstride * pixdata->height);
-        }
-      else
-        {
-          g_free (data);
-          g_set_error_literal (error, GDK_PIXBUF_ERROR,
-                               GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
-                               _("Image pixel data corrupt"));
-          return NULL;
-        }
-    }
+    memcpy (data, pixdata->pixel_data, pixdata->rowstride * pixdata->height);
   else
     data = pixdata->pixel_data;