Currently the `getPath` methods returned `NULL` in case when a file with the specified ID does not exist. This however mandates that developers are checking for the `NULL` case and if they do not the door for bugs with all kind of impact is widely opened.
This is especially harmful if used in context with Views where the final result is limited based on the result of `getPath`, if `getPath` returns `NULL` PHP type juggles this to an empty string resulting in all possible kind of bugs.
While one could argue that this is a misusage of the API the fact is that it is very often misused and an exception will trigger an immediate stop of execution as well as log this behaviour and show a pretty error page.
I also adjusted some usages where I believe that we need to catch these errors, in most cases this is though simply an error that should hard-fail.
The sharing backend may throw another exception for example when the activity app encounters a problem. Previously this just triggered a 404 error page and the exception got not logged at all. With this change such exceptions get not intercepted and regularly handled as exceptions so that we have meaningful log data. Also the user will be shown a window informing him that an error happened.
Helps to debug cases such as https://github.com/owncloud/core/issues/19465
Despite it's PHPDoc the function might return `null` which was not properly catched and thus in some situations the share was resolved to the sharing users root directory.
To test this perform the following steps:
* Share file in owncloud 7 (7.0.4.2)
* Delete the parent folder of the shared file
* The share stays is in the DB and the share via the sharelink is inaccessible. (which is good)
* Upgrade to owncloud 8 (8.0.2) (This step is crucial. The bug is not reproduceable without upgrading from 7 to 8. It seems like the old tokens are handled different than the newer ones)
* Optional Step: Logout, Reset Browser Session, etc.
* Access the share via the old share url: almost empty page, but there is a dowload button which adds a "/download" to the URL.
* Upon clicking, a download.zip is downloaded which contains EVERYTHING from the owncloud directory (of the user who shared the file)
* No exception is thrown and no error is logged.
This will add a check whether the share is a valid one and also adds unit tests to prevent further regressions in the future. Needs to be backported to ownCloud 8.
Adding a proper clean-up of the orphaned shares is out-of-scope and would probably require some kind of FK or so.
Fixes https://github.com/owncloud/core/issues/15097
This is required because the PDF Viewer itself is embedded using an iframe from the same domain. The default policy is blocking this.
Going on further, we have to come up with a solution in the future how to handle previews by applications, one example might be that they call their own endpoint and not the generic share page to allow applications to have full control over how to display previews.
Anyways, to test this behaviour use a decent newer browser (such as Chrome 41) and share a PDF file, obviously the PDF viewer needs to be enabled as well. Without this patch publicly shared PDF files should not get previewed and an error is thrown. (if it isn't then your browser is probably not obeying our Content-Security-Policy and you might consider switching to another one ;))
Robin Appelman
Roeland Jago Douma
Arthur Schiwon
Thomas Müller
Björn Schießle
Scrutinizer Auto-Fixer
Lukas Reschke
Vincent Petry
Morris Jobke
Jenkins for ownCloud
Joas Schilling
Joas Schilling
Bjoern Schiessle
Georg Ehrke
Robin McCorkell