1481223 - Create SUMO article to document Mac Flash Sandbox limitations and instructions to disable

Status: RESOLVED FIXED

(support.mozilla.org :: Knowledge Base Content, task, P1)

Description

[Haik Aftandilian [:haik]]

We are targeting a build 62 release of the Mac Flash sandbox via bug 1474375 "[Mac] Let Sandboxing for the Flash NPAPI plugin process ride the trains". We should create a SUMO article documenting the Flash functionality affected by the sandbox and how to disable the sandbox.

Comment 1

[Liz Henry (:lizzard)]

Tracking this as a blocker for the feature/62 release.

Comment 2

[Chris Peterson [:cpeterson]]

Haik outlined in bug 1474375 comment 3 some of the Flash functionality that will be broken.

Comment 3

[Haik Aftandilian [:haik]]

I've put together a brief write-up for the SUMO article and granted edit access to all at Mozilla. Joni, is that something you can work with?

Comment 4

[Joni Chan]

Thanks for the need info. We've published a SUMO article here: https://support.mozilla.org/en-US/kb/changes-affecting-adobe-flash-firefox-mac

It can be edited at any time if things change.

Comment 5

[Alice Wyman]

(In reply to Joni Savage ("need info" me) from comment #4)
> Thanks for the need info. We've published a SUMO article here:
> https://support.mozilla.org/en-US/kb/changes-affecting-adobe-flash-firefox-mac
> 
> It can be edited at any time if things change.

I don't see instructions to disable the sandbox. Can that be added to the article?

Comment 6

[Chris Peterson [:cpeterson]]

(In reply to Alice Wyman from comment #5)
> I don't see instructions to disable the sandbox. Can that be added to the
> article?

Thanks for catching that omission! The Flash sandbox pref is "dom.ipc.plugins.sandbox-level.flash" and currently defaults to level 1 on macOS. To disable the Flash sandbox, set the pref to 0.

Haik, now that the macOS Flash sandbox level has been reduced from 2 to 1 (by bug 1484380), can we remove some items from the SUMO article's list of broken Flash features?

Comment 7

[Haik Aftandilian [:haik]]

(In reply to Chris Peterson [:cpeterson] from comment #6)
> (In reply to Alice Wyman from comment #5)
> > I don't see instructions to disable the sandbox. Can that be added to the
> > article?
> 
> Thanks for catching that omission! The Flash sandbox pref is
> "dom.ipc.plugins.sandbox-level.flash" and currently defaults to level 1 on
> macOS. To disable the Flash sandbox, set the pref to 0.

And in case it's not clear, that is done via about:config.

> Haik, now that the macOS Flash sandbox level has been reduced from 2 to 1
> (by bug 1484380), can we remove some items from the SUMO article's list of
> broken Flash features?

Unfortunately not. Most of the breakage is due to the plugin not having write access to the filesystem and that is still prevented by the sandbox.

Comment 8

[Alice Wyman]

I made a revision that's pending review, to add steps to disable the sandbox.  See
https://support.mozilla.org/en-US/kb/changes-affecting-adobe-flash-firefox-mac/history

Comment 9

[Chris Peterson [:cpeterson]]

(In reply to Alice Wyman from comment #8)
> I made a revision that's pending review, to add steps to disable the
> sandbox.  See
> https://support.mozilla.org/en-US/kb/changes-affecting-adobe-flash-firefox-
> mac/history

Thanks, Alice. Your article edit looks good to me.

Comment 10

[Alice Wyman]

Thanks for checking my revision, Chris. I published it and cleared my NeedInfo request from Joni.

Comment 11

[Michele Rodaro [:michro]]

Hi, I should localize in Italian the https://support.mozilla.org/en-US/kb/changes-affecting-adobe-flash-firefox-mac article, but I need your help because i don't understand this:
"The sandbox is known to prevent the following features from working:  

* Quicklook in the File->Open dialog

Are we referring to this Quicklook? 
https://en.wikipedia.org/wiki/Quick_Look 

If so, I know Quicklook but I don't understand the procedure to get the File->Open dialog.
The Quicklook I know on Mac: You have a file on your desktop, you click once on the file to select it, you press the space bar and you see a preview of the document without opening the file in its program. 
I suppose we are not referring to that procedure… Can someone clarify this for me? 
Thanks in advance

Comment 12

[Haik Aftandilian [:haik]]

(In reply to Michele Rodaro from comment #11)
> Hi, I should localize in Italian the
> https://support.mozilla.org/en-US/kb/changes-affecting-adobe-flash-firefox-
> mac article, but I need your help because i don't understand this:
> "The sandbox is known to prevent the following features from working:  
> 
> * Quicklook in the File->Open dialog
> 
> Are we referring to this Quicklook? 
> https://en.wikipedia.org/wiki/Quick_Look 
> 
> If so, I know Quicklook but I don't understand the procedure to get the
> File->Open dialog.
> The Quicklook I know on Mac: You have a file on your desktop, you click once
> on the file to select it, you press the space bar and you see a preview of
> the document without opening the file in its program. 
> I suppose we are not referring to that procedure… Can someone clarify this
> for me? 
> Thanks in advance

Yes, that's the feature we're referring to. From within a File->Open dialog, you can select a file and then press space bar and _normally_ that would open the quick look preview on top of the File->Open dialog. From the Flash process, the preview will not not display.

--

Not relevant to the release note, but now that we've reduced the level to 1, we might be able to fix this. I will look into it.

Comment 13

[Michele Rodaro [:michro]]

Thanks Haik :-)
Forgive me, but I'm confused. 
Are we talking about Firefox > menu File > Open file… > in the Mac window that opens, instead of clicking on the Open button, I select a file (what kind of file?) and then I press the space bar to open the quick look preview on top of the File->Open dialog? Because if the steps to reproduce the issue are these, I can open the quick look preview of .txt, .pdf, .xlsx., ecc. in Firefox 62 without problems.
What do you mean with "From the Flash process". Can you suggest me the steps?
Again, forgive me for this waste of time ;-)

Comment 14

[Haik Aftandilian [:haik]]

(In reply to Michele Rodaro from comment #13)
> What do you mean with "From the Flash process". Can you suggest me the steps?
> Again, forgive me for this waste of time ;-)

Sorry for not being clear about that. The issue only applies to dialogs that get opened by the Flash applet. Here's an example Flash file uploader (when you click "Add Files", a file dialog should appear, but you may have to reload to get the applet to work):

  http://www.tinywebgallery.com/en/tfu/web_demo1.php

These dialogs are not implemented in the same way as File->Open dialog from the Firefox File menu. The standard Firefox File->Open menu should continue to work.

Comment 15

[Michele Rodaro [:michro]]

Haik, thank you so much!
I finally realized how it works! From that Flash file uploader if I try to open the quick look preview of a file by pressing the space bar, I get a preview with the message error "An error occurred with the preview of this document". 
I changed the value in the about:config from 1 to 0, closed and restarted Firefox 62 and everything was working fine.
Thanks again ;-)

Comment 16

[Chris Peterson [:cpeterson]]

Resolving fixed because the SUMO article is now live:

https://support.mozilla.org/kb/changes-affecting-adobe-flash-firefox-mac