[CASSANDRA-15262] Update defaults for server and client TLS settings

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 4.0-beta1, 4.0
• Component/s: Local/Config
• Bug Category: Correctness - API / Semantic Implementation
• Severity: Low
• Complexity: Low Hanging Fruit
• Discovered By: Performance Regression Test
• Platform: All
• Since Version: 4.0-alpha1

Source Control Link

https://github.com/apache/cassandra/commit/674b6cc1a5e905a9c234c649adaad2de79cfa560

Test and Documentation Plan

trunk
dtest

• Assignee: Joey Lynch
• Reporter: Joey Lynch

Authors

Joey Lynch

Reviewers

Benedict Elliott Smith, Ekaterina Dimitrova

• Created: 06/Aug/19 21:59
• Updated: 21/Jun/20 02:39
• Resolved: 21/Jun/20 02:39

Description

The current `server_encryption_options` configuration options are as follows:

server_encryption_options:
    # set to true for allowing secure incoming connections
    enabled: false
    # If enabled and optional are both set to true, encrypted and unencrypted connections are handled on the storage_port
    optional: false
    # if enabled, will open up an encrypted listening socket on ssl_storage_port. Should be used
    # during upgrade to 4.0; otherwise, set to false.
    enable_legacy_ssl_storage_port: false
    # on outbound connections, determine which type of peers to securely connect to. 'enabled' must be set to true.
    internode_encryption: none
    keystore: conf/.keystore
    keystore_password: cassandra
    truststore: conf/.truststore
    truststore_password: cassandra
    # More advanced defaults below:
    # protocol: TLS
    # store_type: JKS
    # cipher_suites: [TLS_RSA_WITH_AES_128_CBC_SHA,TLS_RSA_WITH_AES_256_CBC_SHA,TLS_DHE_RSA_WITH_AES_128_CBC_SHA,TLS_DHE_RSA_WITH_AES_256_CBC_SHA,TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA]
    # require_client_auth: false
    # require_endpoint_verification: false

A couple of issues here:
1. optional defaults to false, which will break existing TLS configurations for (from what I can tell) no particularly good reason
2. The provided protocol and cipher suites are not good ideas (in particular encouraging anyone to use CBC ciphers is a bad plan

I propose that before the 4.0 cut we fixup server_encryption_options and even client_encryption_options :

1. Change the default optional setting to true. As the new Netty code intelligently decides to open a TLS connection or not this is the more sensible default (saves operators a step while transitioning to TLS as well)
2. Update the defaults to what netty actually defaults to

Issue Links

• is related to: CASSANDRA-15146 Transitional TLS server configuration options are overly complex