Incorrect Downloads directory for LDAP user in snapped firefox & chromium

[Dariusz Gadomski]

Test procedure:
1. Log in to Gnome as a Active Directory user.
2. Launch browser (firefox or chrome) - make sure there's no existing config (we are interested in the default Downloads location).
3. Download a file via the browser.
4. Check where it was downloaded.

Expected result:
The files are downloaded to ~/Downloads (or a translated equivalent).

Actual result:
The files are downloaded to:
~/snap/firefox/common/Downloads
~/snap/chromium/current/Downloads

For local users the behavior is as expected (all files are downloaded to ~/Downloads).

This is very inconvenient for enterprise environments where manual setting modification is needed on every host.

This has been tested on 22.04 with the following versions:
- firefox (116.0.3 Mozilla Firefox Snap for Ubuntu canonical-002 - 1.0)
- chromium (Version 116.0.5845.110 (Official Build) snap (64-bit))
- snapd 2.58+22.04.1

[1] https://ubuntu.com/server/docs/service-sssd-ad

[Dariusz Gadomski (dgadomski)]

I have been looking into this issue and I've noticed that in snap/command-chain/desktop-launch line 39 cases the issue:

REALHOME=$(getent passwd $UID | cut -d ':' -f 6)

Inside the snap getent passwd $UID returns an empty string for the AD/LDAP user.

[Dariusz Gadomski (dgadomski)]

Simply replacing the line above with:
REALHOME=${SNAP_REAL_HOME}
makes the issue go away.

I'm not sure what was the purpose of the getent call, but clearly it has problems with accessing the passwd database inside the snap sandbox.

[Ken VanDine (ken-vandine)]

The getent implementation pre-dates the existence of SNAP_REAL_HOME. We can probably leverage that.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.