From 6c7c9aa226b57baf3d375457c041c69234936867 Mon Sep 17 00:00:00 2001 From: "Michael J. Chudobiak" Date: Fri, 11 May 2012 09:37:24 -0400 Subject: [PATCH] do not save failed thumbnails for unreadable images --- thumbnail/thumbnail-spec.sgml | 10 ++++++++-- 1 files changed, 8 insertions(+), 2 deletions(-) diff --git a/thumbnail/thumbnail-spec.sgml b/thumbnail/thumbnail-spec.sgml index cb539b6..b9c8411 100644 --- a/thumbnail/thumbnail-spec.sgml +++ b/thumbnail/thumbnail-spec.sgml @@ -455,7 +455,13 @@ in the thumbnail directories should have set their permissions to 600. This way we assure that if a user creates a thumbnail for a file where only he has read-permissions no other user can take a glance on it through the - backdoor with the thumbnails. + backdoor with the thumbnails. + + Programs should first check to ensure that the original image file is + readable. If it is not, the program should not attempt to read a thumbnail + from the cache, and it should not save any information in the cache + (including "failed" thumbnails). Otherwise, thumbnailing will be prevented + even if the permissions are changed to permit reading. Concurrent Thumbnail Creation An important goal @@ -597,7 +603,7 @@ if (file.mtime != thumb.MTime) { with the name of the program appended by the version number (eg. ~/.thumbnails/fail/nautilus-1.0). - For every thumbnail generation failure the program creates an empty + For every thumbnail generation failure of a readable image the program creates an empty PNG file. If it's possible to obtain some additional information from the image (see Store Additional Information) they should be stored together with the thumbnail -- 1.7.7.6