Paul Schaub
1f731f6318
Changes:
Rework integration tests
New structure of base integration test classes
bump dependency on signal-protocol-java from 2.4.0 to 2.6.2
Introduced CachingOmemoStore implementations
Use CachingOmemoStore classes in integration tests
Removed OmemoSession classes (replaced with more logical OmemoRatchet classes)
Consequently also removed load/storeOmemoSession methods from OmemoStore
Removed some clutter from KeyUtil classes
Moved trust decision related code from OmemoStore to TrustCallback
Require authenticated connection for many functions
Add async initialization function in OmemoStore
Refactor omemo test package (/java/org/jivesoftware/smack/omemo -> /java/org/jivesoftware/smackx)
Remove OmemoStore method isFreshInstallation() as well as defaultDeviceId related stuff
FileBasedOmemoStore: Add cleaner methods to store/load base data types (Using tryWithResource, only for future releases, once Android API gets bumped)
Attempt to make OmemoManager thread safe
new logic for getInstanceFor() deviceId determination
OmemoManagers encrypt methods now don't throw exceptions when encryption for some devices fails. Instead message gets encrypted when possible and more information about failures gets returned alongside the message itself
Added OmemoMessage class for that purpose
Reworked entire OmemoService class
Use safer logic for creating trust-ignoring messages (like ratchet-update messages)
Restructure elements/provider in order to prepare for OMEMO namespace bumps
Remove OmemoManager.regenerate() methods in favor of getInstanceFor(connection, randomDeviceId)
Removed some unnecessary configuration options
Prepare for support of more AES message key types
Simplify session creation
Where possible, avoid side effects in methods
Add UntrustedOmemoIdentityException
Add TrustState enum
More improved tests
2 KiB
Migrating smack-omemo from 4.2.1 to 4.x.x
The implementation of smack-omemo and smack-omemo-signal was originally started as an academic project under pressure of time. For that reason, the API was not perfect when OMEMO support was first introduced in Smack in version 4.2.1. Many issues of smack-omemo have been resolved over the course of the last year in a major effort, which is why smack-omemo and smack-omemo-signalwere excluded from the 4.2.2 release.
During this time major parts of the implementation were redone and the API changed as a consequence of that. This guide will go through all notable changes in order to make the process of upgrading as easy and straight forward as possible.
Trust
One major change is, that the OmemoStore implementations no longer store trust decisions.
Methods related to trust have been removed from OmemoStore implementations.
Instead the client is now responsible to store those.
Upon startup, the client now must pass an OmemoTrustCallback to the OmemoManager
which is used to access and change trust decisions.
It is recommended for the client to store trust decisions as tuples of (omemo device, fingerprint of identityKey, trust state). When querying a trust decision (aka. "Is this fingerprint trusted for that device?), the local fingerprint should be compared to the provided fingerprint.
The method signatures for setting and querying trust from inside the OmemoManager are
still the same. Internally they access the OmemoTrustCallback set by the client.
Encryption
Message encryption in smack-omemo 4.2.1 was ugly. Encryption for multiple devices
could fail because session negotiation could go wrong, which resulted in an
exception, which contained all devices with working sessions.
That exception could then be used in
OmemoManager.encryptForExistingSessions(CannotEstablishOmemoSessionException exception, String message),
to encrypt the message for all devices with a session.
The new API is