Update mimetype handling and --view-only for open-in-dvm

[emkll]

Status

Ready for review

❗ Temporary commit will need to be removed prior to merge ❗
This is due to the use of https://github.com/freedomofpress/securedrop-workstation/wiki/Evaluating-new-deb-package-behavior for reviewer convenience

The reviewer of this PR should also review and merge the following PRs before merging this one:

• securedrop-workstation-svs-disp and securedrop-export 0.2.2 securedrop-builder#155
• View-only when opening in dvm, update mimeapps.list securedrop-client#972
• Update mimeapps for securedrop-export, securedrop-export 0.2.2 securedrop-export#60

Description of Changes

Fixes freedomofpress/securedrop-client#960
Fixes freedomofpress/securedrop-client#961

Testing

In a dev VM:

• Visually review diffs in the 3 PRs above
• Build securedrop-client, securedrop-export and securedrop-workstation-svs-disp on the branches onf the PRs in the section above
• copy built debs in sd-workstation folder

In dom0:

• make clone and move config.json and sd-journalist.sec in place, if necessary
• make all completes without issue
• make test all tests pass (except update tests for sd-app, due to 0.1.3 < 0.1.3 nightly series)

In Tor browser

• submit a desktop file to source interface (debian-xterm.desktop works well since it's installed in most places)

In sd-app

• Client opens desktop file in dvm (and in gedit)
• xdg-open that file on disk manually (from /home/user/.securedrop-client/data/...) opens in a dvm
• Modify rules to permit Qubes.Filecopy from sd-app to sd-devices, and copy desktop file to sd-devices
• xdg-open that file on disk manually (from ~/QubesIncoming/sd-app/...) opens in a dvm (I recommend you use a plaintext file for convenience for next step)
• In the DispVM, the file is opened in read-only mode
• manually editing the file in /tmp/sd-app... and then closing the application does not modify the file in sd-app

Checklist

If you have made code changes

If you have made changes to the provisioning logic

• All tests (make test) pass in dom0 of a Qubes install

[conorsch]

After building custom debs as described, then rebuilding locally, the changes here work well. I ran into a snag with the "all tests pass," related to v3 onions and --verify behavior. Pushed up a fix to run the check as the debian-tor user; if you've got v2 services enabled, would appreciate confirming it works well there too.

While I was able to confirm that gedit was used after submitting a .desktop file, and I wasn't able to save changes in the DVM (one of the core resolutions this PR aims for), testing with xdg-open inside sd-app did allow me to clobber the originally submitted file. Therefore we need updates to the corresponding package PRs in order to update the open-in-dvm behavior. For the context of the Client, we always want the open-in-dvm behavior to be read-only, so updating the corresponding desktop file will ensure that even xdg-open makes it read-only. Such a change is still in the spirit of defense-in-depth, given that the client explicitly calls qvm-open-in-dvm itself.

[emkll]

Thanks for the review and fixing the tor test case @conorsch . Your comments should now be addressed in respective repositories, also added tests here for the open-in-dvm desktop file. I have also updated the test plan accordingly.

[conorsch]

Rebuilt local packages, ran through test plan, everything working beautifully. Test plan report:

---

In dom0:

• make clone and move config.json and sd-journalist.sec in place, if necessary
• make all completes without issue
• make test all tests pass (except update tests for sd-app, due to 0.1.3 < 0.1.3 nightly series)

In Tor browser

• submit a desktop file to source interface (debian-xterm.desktop works well since it's installed in most places)

In sd-app

• Client opens desktop file in dvm (and in gedit)
• xdg-open that file on disk manually (from /home/user/.securedrop-client/data/...) opens in a dvm
• Modify rules to permit Qubes.Filecopy from sd-app to sd-devices, and copy desktop file to sd-devices
• xdg-open that file on disk manually (from ~/QubesIncoming/sd-app/...) opens in a dvm (I recommend you use a plaintext file for convenience for next step)
  • FWIW, I used the same .desktop file here, since it was opening gedit, and easy to test read-only mode
• In the DispVM, the file is opened in read-only mode
• manually editing the file in /tmp/sd-app... and then closing the application does not modify the file in sd-app
  • technically, i used gedit to modify the text, then tried to save, and observed failure. on the previous round of testing, before the --view-only flag was added to the open-in-dvm desktop file, the save operation was successful, and changes were propagated back to the calling VM. that's no longer the case, which is good!

---

Not formally approving just yet, since we still need to snip out the TEMPORARY commit (will do so shortly), as well as approve the other related PRs. All PRs should be merged together in order to avoid problems.

[conorsch]

Rebased on top of latest master (505a616), and removed temporary commit as requested.

[conorsch]

Test plan is passing. All related PRs have been reviewed and merged.