Re: Able to write to read-only pdf files

[Adriano Vilela Barbosa <adriano.vilela@gmail.com>]

On Sat, 14 Aug 2021 at 12:54, bruno zanetti <bzanetti00@gmail.com> wrote:
>
> Il giorno sab 14 ago 2021 alle ore 15:39 Adriano Vilela Barbosa <adriano.vilela@gmail.com> ha scritto:
>>
>> Hello,
>>
>> Yesterday I came across a very weird behavior while annotating a pdf
>> file in Okular. Long story short: I opened a read-only pdf file
>> (permissions: 400), inserted some comments and hit the save button. At
>> this point, I thought I had been working on a write-enabled copy of
>> the file. After a while, I realized that I was actually working on the
>> read-only version of the file, that somehow got saved to disk when I
>> hit the save icon. Okular was not only able to save the file to disk,
>> but the file permissions were changed to 644.
>>
>> I initially thought this was an Okular problem. However, after some
>> more testing, I was able to reproduce the problem with Xournal. This
>> makes me think that the problem is not with Okular or Xournal, but
>> with some common library used by both of these packages (maybe
>> libpoppler?).
>>
>> Has anybody had this problem? Can anybody reproduce it?
>>
>> I'm using Debian testing.
>>
>> Thanks a lot,
>>
>> Adriano
>
>
> Hi Adriano,
> the read-only permission on the pdf file just prevents it's contents to be changed. It still can be deleted if the directory it belongs to is not write protected.
> Editor programs usually do not directly change the contents of a file but rather save them to a temporary new one (with default permissions), delete the original and then rename the new file replacing the original one. I don't know if Okular works this way, but I think it quite likely does.
>
> Have a good release day!
>
> Bruno
>
>

Hi Bruno,

Thanks for your reply.

Indeed, what you describe may be what's happening. If I change the
permissions of the directory where the file is to read-only, I get an
error message when trying to save the file. The error message says the
file could not be saved (error: access denied), and also says that it
could not write to file.pdf.part (this .part file must be temporary
file you mentioned).

I understand this mechanism, but I think this is quite controversial
and problematic. I mean, as an end user I don't care what the editor
is doing behind the scenes; it just shouldn't be able to modify a file
marked as read-only.

This is the first time I came across this behavior. No text editor I
ever used does this; LibreOffice doesn't do it either (rather, it
shows a message saying the document is open in read-only and shows an
"Edit Document" button, which allows you to edit the document and then
save it under a different name).

The question is: should I file a bug report somewhere? I really don't
want editors overwriting my read-only documents...

Thanks again,

Adriano