[TheDong]

> The FAQ page states "We are explicitly using many features of the linux kernel (bind mounts, namespaces, seccomp, etc) to create the sandbox that Flatpak apps are running in." ... and then it turns out that they aren't, or at least they aren't enforcing it

They are using those features. flatpak has network namespaces for applications that don't need access to the network and bindmounts for applications that use very limited parts of the filesystem.

Sure, in reality many desktop apps have more far-reaching permissions, but all they're saying is that flatpak can make use of those features in some cases.

> This is flat out lying to try and get mindshare

Usually that's just called marketing. I don't think any of the above statements are actually lies in any way though. Can you point to what's actually a lie, or what lie is implied in your mind?

[jessaustin]

The part where they say it's a sandbox, and it doesn't even attempt to be a sandbox. That's a lie.

[derefr]

It's a sandbox like Android has a sandbox: each app lists a set of capabilities; the user gets a dialogue on installation where they have to grant those capabilities (or else cancel the install); and then for anything the app tries to do that's not in that set of capabilities, it fails.

A sandbox doesn't mean "you can never do [foo]." A sandbox means "you can never doo [foo] unless the user lets you." Even web browsers (the classical "true sandboxes") have an API that gets you access to the user's microphone, and another for access to their GPS data. There's just a dialogue in between that the user can say "No" to; and, having said no, the content of the tab can't ask again, and just gets denied automatically. That's what makes it a sandbox.

[jonstewart]

Is it also like Android's "sandbox" in that every application asks for every permission and the only choice is between "no security" and "can't install anything useful" and inures the user to just click "accept" on everything?

[Ndymium]

Android's permission system was overhauled in version 6 so that permissions are now generally asked when they are needed, for a specific type of operation, instead of the big dialog when installing.

I personally use several apps where I have granted one set of permissions and denied another (because it was for a feature I don't use). It has gotten a lot better than what it used to be.

[MayeulC]

For now, the GUIs are as far as I know, but there is a `flatpak override` command that seems promising for changing an installed application's permissions.

[viraptor]

The system is configured to run apps in a sandbox though - that's completely true. It's the app's part that declares: it needs full access to your home directory to work. If that wasn't possible, we'd get people complaining about apps not working as expected instead. The balance may not be currently on the right side, but they don't lie about what's provided.

It's like standard Linux permissions. If you install an app which creates its directories with mode 0777, or install a package which has a suid binary, you don't complain that Linux offers no file access control. That's the author's or packager's fault.

[yzmtf2008]

“Sandbox” and “full access to your home directory” doesn’t compute. That’s literally one of the biggest reasons to sandbox applications.

[michaelmrose]

Nobody wants a packaging system that can't package existing apps not designed to be secure in a useful fashion.

In a traditional app packaged as a deb/rpm the developer releases the source which then must be packaged and made to work with each distribution/platform. If the app is malicious or is sold to someone/compromised by someone who is then you are 100% hosed.

In a flatpak not designed to be properly sandboxed you are in fact no worse off than the alternative deb/rpm situation save that the issue of packing for distribution has been made easier.

It's in fact probably extremely challenging to package all sorts of applications without giving the user the option to provide an individual app elevated permissions.

At best we are relying on the user to decide which app ought to get those permissions.

If you think people can't be trusted to do this then the logical solution is to rely on packagers to decide what belongs in the official repo and keep malicious content out.

[comex]

Well, the ideal solution is to fix the application to use the special file chooser that gives the app permission to access whatever files the user chose. I only know the basics about Flatpak, but I know it has such a file chooser; does Gimp not use it, or is there some other issue that makes it require full home directory access?

In the meantime – sure, package the app, but it shouldn’t show up as “sandboxed” in the GUI if the sandbox isn’t meaningful. Instead it should come with a nice scary warning that the app has access to all of your files… you know, for everyone to ignore and click through. (You can lead a horse to water…)

[yellowapple]

In flatpak you are worse off, though, since - as the article indicates - they lag behind on security updates. If they get compromised by unpatched exploits, that sandbox is a valuable line of defense.

[danilocesar]

The writer tries to blame Flatpak for app maintainers mistakes. That isn't fair.

If an app doesn't get an security fix whoever maintains that package should be the one to blame.

Disclaimer: I don't like flatpak either, I'm just trying to be fair here...

[viraptor]

It depends on your use case. If you sandbox tar (for example), you'd do it be removing all network access and a few fancy caps, but you'd leave the rw access to the whole system. (within its standard privileges) If you sandbox netcat, you'd do the opposite: remove all fs access (unless you care about pipes) and leave open networking.

There's nothing about the idea of a sandbox that requires a specific approach.

[voltagex_]

Have a look at AppV on Windows. It isn't great, but all I/O is redirected, so in your example, tar would think that it's writing to /home/voltagex but it might actually be writing to /run/sandbox/blah/home/voltagex - so if something ran rm -rf it'd only delete the sandboxed home.

[AnthonyMouse]

> It isn't great, but all I/O is redirected, so in your example, tar would think that it's writing to /home/voltagex but it might actually be writing to /run/sandbox/blah/home/voltagex - so if something ran rm -rf it'd only delete the sandboxed home.

Then how do you get it to operate on your actual home directory when you want it to? Making it operate on some different structure has been possible with chroot() or LVM snapshots or a number of other things for a long time.

[untog]

It's true, but I'm not sure how e.g. VS Code would even work on a truly sandboxes environment. There'd be no file browser.

[yzmtf2008]

macOS does this via the open dialog — opening a directory gives an application full access to that directory

[m45t3r]

And you can have the same issue the author said in the article by requesting access to home directory and running the exactly the same command as the author wrote.

[pcwalton]

Same way it works on the web: Use a broker process that grants access via a file select dialog.

[vetinari]

The point is, that for vscode picking a file is not enough. It would cause lot of fun opening multi-root workspaces you just checked out...

There are many more applications, not just IDEs, where picking a file or folder is not sufficient: for example, apps like Rapid Photo Downloader or Darktable would be significantly crippled.

[voltagex_]

Virtualised paths with specific access - i.e. VS Code would only see one path.

[TheDong]

"sandbox" is an ill defined term, but what flatpak provides fits it perfectly well.

A sandbox is an environment where capabilities can be restricted in a set of ways.

The javascript sandbox lets you manipulate the website and make network requests, but not access arbitrary files.

The flatpak sandbox is configured per-app and can prevent all fs access, all file io (with seccomp), all networking, etc.

The article is simply pointing out that most popular applications do not use the sandbox features well.

That doesn't mean flatpak does not have the sandbox they claim to, merely that it does not mesh well with many popular apps currently.

I still see nothing that merits the word "lie".