[Bug]: v3.8.0 basically KILLS E2EE ("Error with the metadata. Getting unexpected metadata format.")

[bcutter]

⚠️ Before submitting, please verify the following: ⚠️

• This is a bug, not a question or a configuration issue.
• This issue is not already reported on Github (I've searched it).
• Nextcloud Server and Desktop Client are up to date. See Server Maintenance and Release Schedule and Desktop Releases for supported versions.
• I agree to follow Nextcloud's Code of Conduct

Bug description

After updating to desktop client v3.8.0 I started to see strange sync issues. Encrypted changed and created files could not be synced with the server anymore.

• I thought "well, just that time of the year E2EE had its hiccups, just start over" and spent almost 4 hours in resetting E2EE.
• In the end it did fix nothing.

With v3.8.0 there are metadata issues. Clients give Error with the metadata. Getting unexpected metadata format..

Steps to reproduce

1. Start fresh with E2EE for a user by resetting E2EE (meta-data, private key, public key, potential file lock entries, corresponding filecache entries, delete all previously existing E2EE folders, run occ files:scan-app-data etc.)
2. Desktop client with 3.8.0: enable E2EE by setting a passphrase
3. Another client (I used the iOS app): clear E2EE from settings, supply same (new) passphrase as set in step 2
4. Desktop client: create a new empty folder and encrypt it, put one file in it
5. iOS client: try to access the encrypted folder

Note: you can also create the folder on the iOS client and try to access it from the desktop client, same result.

Expected behavior

Access is possible as usual.

Which files are affected by this bug

All E2EEncrypted!

Operating system

Windows

Which version of the operating system you are running.

Windows 10

Package

Appimage

Nextcloud Server version

25.0.5.1

Nextcloud Desktop Client version

3.8.0

Is this bug present after an update or on a fresh install?

Updated to a major version (ex. 3.3.6 to 3.4.0)

Are you using the Nextcloud Server Encryption module?

Encryption is Enabled

Are you using an external user-backend?

• Default internal user-backend
• LDAP/ Active Directory
• SSO - SAML
• Other

Nextcloud Server logs

This seems to be the initial issue (not fully sure):

{"reqId":"zCH6yCfRIeEVQuTq6QP7","level":3,"time":"2023-04-03T20:34:34+02:00","remoteAddr":"xxx.xxx.xxx.xxx","user":"Username","app":"no app in context","method":"DELETE","url":"/ocs/v2.php/apps/end_to_end_encryption/api/v1/lock/871525","message":"Intermediate meta-data file missing","userAgent":"Mozilla/5.0 (Windows) mirall/3.8.0stable-Win64 (build 20230331) (Nextcloud, windows-10.0.19045 ClientArchitecture: x86_64 OsArchitecture: x86_64)","version":"25.0.5.1","exception":{"Exception":"OCA\\EndToEndEncryption\\Exceptions\\MissingMetaDataException","Message":"Intermediate meta-data file missing","Code":0,"Trace":[{"file":"/var/www/nextcloud/apps/end_to_end_encryption/lib/Controller/LockingController.php","line":133,"function":"saveIntermediateFile","class":"OCA\\EndToEndEncryption\\MetaDataStorage","type":"->"},{"file":"/var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php","line":225,"function":"unlockFolder","class":"OCA\\EndToEndEncryption\\Controller\\LockingController","type":"->"},{"file":"/var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php","line":133,"function":"executeController","class":"OC\\AppFramework\\Http\\Dispatcher","type":"->"},{"file":"/var/www/nextcloud/lib/private/AppFramework/App.php","line":172,"function":"dispatch","class":"OC\\AppFramework\\Http\\Dispatcher","type":"->"},{"file":"/var/www/nextcloud/lib/private/Route/Router.php","line":298,"function":"main","class":"OC\\AppFramework\\App","type":"::"},{"file":"/var/www/nextcloud/ocs/v1.php","line":63,"function":"match","class":"OC\\Route\\Router","type":"->"},{"file":"/var/www/nextcloud/ocs/v2.php","line":23,"args":["/var/www/nextcloud/ocs/v1.php"],"function":"require_once"}],"File":"/var/www/nextcloud/apps/end_to_end_encryption/lib/MetaDataStorage.php","Line":174,"CustomMessage":"--"}}

Nothing in logs for the client messages "Error with the metadata. Getting unexpected metadata format." !!!

Additional info

You should maybe have a look at what you did in e. g. (quick screening for E2E relevant changes)

• skip e2e encrypted files with empty filename in metadata #5448
• E2EE cut extra zeroes from derypted byte array. #5534
• Feature/e2ee fixes #5560

I downgraded to 3.7.4 and everything is working as expected/normal! No more sync issues or error messages. Just a bit of data loss and loss of 4 hours... thanks.

Currently in rage mode and not willing to upgrade to 3.8.0 again to provide desktop client logs. Sorry.

[mgallien]

@bcutter sorry to hear that
can you share a debug archive ?
I can provide a secure share link for you to share it privately with us (and yes we have to keep this secret via a signed paper)

[VanHell1638]

Hi,
@mgallien i can provide the needed debug archive. Please send me the secure share link.

[mgallien]

@VanHell1638 I will delay this as I have found an issue in the end-to-end encryption implementation of the desktop client that is not conform to the specification
I will work on a fix and will see if I can find a workaround to allow recovery from the bug
very sorry for that

[mgallien]

just as a note, I did fix an issue with a missing part in the e2ee implementation of desktop client in 3.8.0
#5570
release is a work in progress #5569

[mgallien]

not sure how you can recover
at least if the files are still correct and accessible on your client, doing any modification may be enough
I will look into this after the release is done

[bcutter]

TBH after almost 5 lost hours yesterday I'm still not (yet) in the needed mood so providing debugs... better refer to @VanHell1638.

Just as note: I fixed this FOR ME by doing a full E2EE reset, downgrading desktop client (and blocking auto update on all other machines to stay at 3.7.4 for now) and re-syncing all E2EE content. Probably just downgrading would have been enough and the 3 to 4 hours of E2EE reset party was oversized.

I will test any new desktop client version claiming to have this fixed of course.

[mgallien]

#5572 should enable automatic recovery from broken checksums

[mgallien]

both fix will be in 3.8.1 release

[bcutter]

I will test 3.8.1 once it is released.