Fix issue 'You are not authorized to add a link' with thumbnails enabled

Do not try to alter the datastore by updating thumbnails if the user isn't logged in.

Also, do not enable thumbnails if PHP GD extension is not installed/loaded

2 files changed, 3 insertions, 3 deletions

diff --git a/application/Updater.php b/application/Updater.php
index c2aa1568..480bff82 100644
--- a/application/Updater.php
+++ b/application/Updater.php
@@ -502,7 +502,7 @@ class Updater
             return true;
         }
 
-        $thumbnailsEnabled = $this->conf->get('thumbnail.enable_thumbnails', true);
+        $thumbnailsEnabled = extension_loaded('gd') && $this->conf->get('thumbnail.enable_thumbnails', true);
         $this->conf->set('thumbnails.mode', $thumbnailsEnabled ? Thumbnailer::MODE_ALL : Thumbnailer::MODE_NONE);
         $this->conf->set('thumbnails.width', 125);
         $this->conf->set('thumbnails.height', 90);
diff --git a/index.php b/index.php
index 925d47a5..4b86a3e2 100644
--- a/index.php
+++ b/index.php
@@ -1635,9 +1635,9 @@ function buildLinkList($PAGE, $LINKSDB, $conf, $pluginManager, $loginManager)
         uasort($taglist, 'strcasecmp');
         $link['taglist'] = $taglist;
 
-        // Thumbnails enabled, not a note,
+        // Logged in, thumbnails enabled, not a note,
         // and (never retrieved yet or no valid cache file)
-        if ($thumbnailsEnabled && $link['url'][0] != '?'
+        if ($loginManager->isLoggedIn() && $thumbnailsEnabled && $link['url'][0] != '?'
             && (! isset($link['thumbnail']) || ($link['thumbnail'] !== false && ! is_file($link['thumbnail'])))
         ) {
             $elem = $LINKSDB[$keys[$i]];