Avoid host filesystem permissions and polluting home folder as much as possible

[JaneSmith]

One of the things I love about Flatpaks is that they typically don't pollute the home directory, as all their configuration and data files go into their own directory within ~/.var. I've noticed that with this package, a ~/Unity directory is created, polluting the home directory. I'd really like to avoid this.

I understand that this package has access to the host filesystem, and Unity Hub wants to create that directory, so it does as it has access. Presumably, taking away access to the host filesystem would break the app in some way as it isn't able to properly handle it?

I feel like I've seen some Flatpak apps though that have access to the host filesystem, while still storing their own things within ~/.var. Could this package be configured to do the same thing? Wouldn't it just be a matter of the app being told that ~/.var/com.unity.UnityHub/ is its home directory, while still having full filesystem access?

Thanks.

[refi64]

We already avoid polluting it in some ways, e.g. patching the binaries to avoid writing data to ~/.unity3d and such, but ~/Unity is a default the editor itself seems to prefer so there's no trivial way of patching that out. The app needs host filesystem access because Electron apps don't use the XDG portals.

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On Sun, Jun 21, 2020 at 11:06 AM JaneSmith ***@***.***> wrote: One of the things I love about Flatpaks is that they typically don't pollute the home directory, as all their configuration and data files go into their own directory within ~/.var. I've noticed that with this package, a ~/Unity directory is created, polluting the home directory. I'd really like to avoid this. I understand that this package has access to the host filesystem, and Unity Hub wants to create that directory, so it does as it has access. Presumably, taking away access to the host filesystem would break the app in some way as it isn't able to properly handle it? I feel like I've seen some Flatpak apps though that have access to the host filesystem, while still storing their own things within ~/.var. Could this package be configured to do the same thing? Wouldn't it just be a matter of the app being told that ~/.var/com.unity.UnityHub/ is its home directory, while still having full filesystem access? Thanks. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#40>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAM4YSN72KM6PED3OQJ4DKLRXYVYLANCNFSM4OD5MURQ> .

-- Ryan (ライアン) Yoko Shimomura, ryo (supercell/EGOIST), Hiroyuki Sawano >> everyone else https://refi64.com/

[NoTuxNoBux]

The app needs host filesystem access because Electron apps don't use the XDG portals.

Is this still relevant today with the latest versions? I have been able to use UnityHub and Unity without host and even home folder filesystem access for several months now with Android and desktop development and no major issues.

I've encountered two issues with doing that so far:

• ~/.upmconfig.toml needs to be added to the filesystem paths and still pollutes my home folder as I can't figure out how to have a root home folder file be in .var/app/... (might just be me).
• .config/unity3d needs to be added back to persistent folders, otherwise layouts and keymaps aren't persisted between editor restarts.
• Similarly .cache/Unity needs to be added to the persistent folders to keep the Unity UPM cache around.

(It seems especially relevant to me for this Flatpak because Unity and its hub are proprietary and should be sandboxed as much as possible from a security and privacy perspective.)

[NoTuxNoBux]

Going to reopen this since it should at least partially be possible. I've been using this Flatpak for years now without host filesystem nor full home folder access. I haven't succeeded in getting ~/.upmconfig.toml out of my home folder, but the rest of the files seem to be isolated to the Flatpak.

I haven't encountered any problems yet even when removing all filesystem permissions and by adding my project folder manually through Flatseal. Unfortunately that's hard to do for everyone and as some users will just expect the Flatpak to work and not be tech-savvy enough to add that permission, it's hard to take away everything by default, but I think we should at least be able to downgrade to the home folder instead of the full host filesystem by default.

[Sytoplis]

Why is this an issue at all? Can't you just add all home directory folders to the default persistent directory list in the flatpak and remove permissions to write them to the actual home directory? As far as I am aware, this works from the programs view the same way, so you don't need to change anything about unity, but flatpak keeps these folders in ~/.var instead of them being in the home directory.

[NoTuxNoBux]

I'm fairly certain we can indeed at least do away with the host filesystem permission and replace it with the home one.

Taking away the home folder permission as well might result in problems as some people might have their Unity projects somewhere inside a non-hidden folder in their home folder. Instead the hub and editor will see Flatpak-mapped paths, which shouldn't be different from the actual path but they are managed by Flatpak and it would surprise me if Unity - especially the editor as the hub seems to use Electron - didn't have edge-cases where that can break things; I've already experienced the hub (3.12.0) getting confused about these paths and refusing to start projects if they are not directly mapped.

Of course one can rather simply map their projects folder using Flatseal to fix that and still take away the rest, but we can't assume users know about that or will be able to do so. I also don't think Unity or the hub properly support portals yet since at least the editor doesn't even have Wayland support yet.

EDIT: Also, I haven't succeeded in configuring ~/.upmconfig.toml from the Flatpak ~/.var/... folder; I only got Unity to pick it up when it was mapped as --filesystem=~/.upmconfig.toml so far (when the home folder permission is disabled as well).

[NoTuxNoBux]

Maybe the new XDG projects directory is a better candidate to set as default than the home folder. It is less wide and likely won't require additional exclusions from the Flathub side. It also allows us to standardise on a common folder to point end-users towards that doesn't need adding to Flatseal.

At the moment of writing it's probably a bit early to make the change, though:

• The xdg-user-dirs change is from a few months ago, distros might not have updated yet (so not everyone might have this folder yet in their home folder).
• I'm not sure there is an xdg-projects permission we can add to the Flatpak manifest; it's not listed in the documentation in any case.