Add opt-in option to work with E2EE encrypted files in Web Interface

[sorbaugh]

The problem:

Currently, working with E2EE only works with clients. There should be an opt-in feature (disabled by default) to be able to work with encrypted files on the web interface as well

First step: read only

Since this would be a bit of work to implement, we should start with the following (avoiding anything that involves writing metadata as a first step):

• Settings entry to enable viewing encrypted files (app settings, not admin). Add a warning about limitation of features. ✏️ (text)
• Support browsing and viewing of encrypted files
• Add ways to share the mnemonic with the server
• Open office files in view only mode? would this be possible @juliusknorr?
• Possibly an icon somewhere in the files list file item that shows that the file is encrypted ✏️

[joshtrichards]

Some prior work on this: nextcloud/end_to_end_encryption#497

[artonge]

Initial version released as v1.17-beta.1

[artonge]

• For item n°1: feat: Add config switch to enable E2EE in browser end_to_end_encryption#830
• For item n°2: feat: Minimal support E2EE file navigation in browser end_to_end_encryption#822
• For item n°3: feat: Minimal support E2EE file navigation in browser end_to_end_encryption#822
• For item n°4: Nothing yet. For information, the response of all GET requests on remote.php is decrypted
• For item n°5: Need design input, for now, a key icon is displayed on the folders' icon.

[artonge]

Thinking out load: we could move the logic into a browser extension, this would remove the thirdparty server admin threat.

[artonge]

Moving follow-ups from nextcloud/end_to_end_encryption#822

Follow-ups

• Add toggle to enable E2EE in browser - feat: Add config switch to enable E2EE in browser end_to_end_encryption#830
• Disable sharing tab in sidebar fix: Remove some permissions to e2ee nodes to hide some file actions end_to_end_encryption#831
• Disable some actions
  • move fix: Remove some permissions to e2ee nodes to hide some file actions end_to_end_encryption#831
  • delete fix: Remove some permissions to e2ee nodes to hide some file actions end_to_end_encryption#831
  • rename fix: Remove some permissions to e2ee nodes to hide some file actions end_to_end_encryption#831
  • share fix: Remove some permissions to e2ee nodes to hide some file actions end_to_end_encryption#831
  • copy feat: Disable copy and download files actions end_to_end_encryption#857
  • download feat: Disable copy and download files actions end_to_end_encryption#857
• Create a download unencrypted action feat: Add download unencrypted action end_to_end_encryption#832
• Fix viewer to display raw file when edit is not possible (maybe we need to simply tweak the permissions)
  • Text and office files could get displayed read only and fetched through a GET request
  • Image, video, sounds, this will be trickier as the requests are done through the DOM, so not intercepted by the proxy. Could be done by passing the media content to the HTML elements like for SVGs feat: Fallback to manually loading media on error viewer#2691 feat: Allow loading media as blob: end_to_end_encryption#867
    • A better long term solution would be to move the proxy logic to either:
      • a service worker. This would require our libs to use self instead of window.
      • a browser extension.
• Store mnemonic locally with Credential Management API: https://developer.mozilla.org/en-US/docs/Web/API/Credential_Management_API
• Improve verification as per the RFC: https://github.com/nextcloud/end_to_end_encryption_rfc/blob/v2.2/RFC.md
  • check counter: new counter must be greater than locally stored counter, No need as we are not storing the data locally
  • check signature - feat: Validate metadata signature end_to_end_encryption#853
  • check that hash of metadata-key is in keyChecksums feat: Verify metadata key against checksum end_to_end_encryption#834
  • check that no hash has been removed from the keyChecksums feat: Validate keyChecksum length end_to_end_encryption#859
  • check if cert of all users is issued by the CA - can be implemented when we need the users' public keys feat: Validate signature of users' certificate in metadata end_to_end_encryption#852

[artonge]

Beta 2 released: https://github.com/nextcloud/end_to_end_encryption/releases/tag/v1.17.0-beta.2

[juliusknorr]

Sorry just seen this now.

Open office files in view only mode? would this be possible @juliusknorr?

For markdown files and the text app this is feasible, for actual office files not since with Collabora the file is rendered on the server, so we need to have it available there.

[artonge]

Beta 3 released: https://github.com/nextcloud/end_to_end_encryption/releases/tag/v1.17.0-beta.3

[ostasevych]

Sorry just seen this now.

Open office files in view only mode? would this be possible @juliusknorr?

For markdown files and the text app this is feasible, for actual office files not since with Collabora the file is rendered on the server, so we need to have it available there.

What about other online editors, which use client side rendering?