Neutron/LBaaS/SSL

Description
Terminating TLS connection on the load balancer and encrypting traffic back to the back end nodes, is a capabilities expected from modern load balancers and incorporated into many applications. This capability enables better certificate management and improved application based load balancing (ex: cookie based persistency, L7 Policies, etc.)

For giving LBaaS TLS termination ability, new extension called TLS will be added.

Overview

 * Tenant will manage his TLS certificates using Barbican. Certificates will be stored in Barbican secure containers
 * Tenant will manage his TLS policies using Neutron. Policies will be stored in neutron schema
 * In addition to existing HTTP, HTTPS and TCP, new protocol, TLS will be added for VIP listener creation
 * For tenant, creating VIP listener with TLS as a protocol means desire to offload incoming encrypted traffic or/and encrypting outgoing traffic to the back-end servers.


 * When creating VIP listener with TLS protocol:
 * Not necessary to supply TLS policy - default behavior will be implemented, partly configurable in neutron configuration file:
 * Front-end TLS offloading enabled, back-end re-encryption disabled - hard coded as a default behavior in code
 * Front-end / Back-end supported protocols and cipher suites are listed in neutron configuration file. This is editable via neutron configuration file
 * If no policy associated and default behavior will take place - tenant must supply default TLS certificate for front-end offloading
 * If policy associated and the policy disables front-end offloading but enables back-end re-encryption - tenant must not supply default TLS certificate for front-end offloading
 * SNI certificates are not mandatory to specify
 * SNI certificates list specifying manner and treatment proposals are posted in "Proposals for SNI certificates list specifying and treating" section and should be discussed
 * Certificates chain for front-end certificates will be not be supported in this phase
 * Front-end client authentication and back-end server authentication will not be supported in this phase

With stated above, following is a description of a basic tenant use case - creating VIP listener with TLS offloading: As a result, VIP listener created, offloading encrypted traffic on front-end with default tenant's TLS certificate, not re-encrypting traffic to the back-end.
 * Creating VIP listener with TLS as a listener protocol
 * Specifying default TLS certificate for front-end offloading by supplying Barbican's TLS certificate container ID

Neutron LBaaS to Barbican API requirements

 * need API for getting whole TLS certificate container, including private key, by container id
 * need API for getting TLS certificates x.509 certificate

TLS Certificates Management
TLS certificates will be store in Barbican certificate containers that contain the TLS certificate itself and its private key. We should also examine the need to perform certificate sign requests using Barbican.

Tenant will be able to create (add), delete (remove) and update TLS certificates using Barbican

Creating TLS certificate (using Barbican)

 * Name : text field
 * Description : text field
 * Certificate : PEM file name
 * Private key: PEM file name (optional)
 * Pass phrase : text field (optional)

Deleting TLS certificate (using Barbican)
Preceded by confirmation. Certificates that are used by VIP listener/s can not be deleted

Updating TLS certificate (using Brbican)

 * Only name and description may be modified

Note: If changed certificate is associated with VIP listener(s), each back-end service provider (driver) should make any required changes

TLS Policies Management
https://www.openssl.org/docs/apps/ciphers.html
 * TLS policies will be stored in neutron schema
 * Tenant will be able to "Add" (create), "Delete" (remove) and update TLS policies.
 * Default TLS policy behavior description:
 * Front-end offloading is enabled (hard-coded)
 * Default front-end supported protocols - SSL v3.0, TLS v1.0, TLS v1.2 (configurable via neutron configuration file)
 * Default front-end supported cipher suites - OpenSSL LOW cipher suite group (configurable via neutron configuration file)
 * Back-end re-encryption is disabled (hard-coded)
 * Default back-end supported protocols - SSL v3.0, TLS v1.0, TLS v1.2 (configurable via neutron configuration file)
 * Default back-end supported cipher suites - OpenSSL LOW cipher suite group (configurable via neutron configuration file)
 * The proposal is to use OpenSSL cipher suite groups (all, low, medium, high) as options to define cipher suites
 * (TBD) We may also give tenant an option to compile his own cipher suite group

Creating TLS policy
Note: 1.Policy with both, front-end offloading and back-end re-encryption, disabled - is invalid 2.When creating TLS policy ,default values for all parameters are derived from the default TLS policy behavior (described above).


 * Name : text field
 * Description : text field
 * Enable Front-End offloading : check box (requires default TLS certificate specification)
 * Enable Back-End encryption : check box
 * Front-End supported protocols : multiple selector from the list of options (SSL v3.0, TLS v1.0, TLS v1.2), at least one should be selected
 * Front-End supported cipher suites : Radio button with 4 choices:
 * ALL: (OpenSSL ALL ciphers group )
 * LOW (OpenSSL LOW ciphers group)
 * MEDIUM (OpenSSL MEDIUM ciphers group)
 * HIGH (OpenSSL HIGH ciphers group)
 * Back-End supported protocols : multiple selector from the list of options (SSL v3.0, TLS v1.0, TLS v1.2), at least one should be selected
 * Back-End supported cipher suites : Radio button with 4 choices (similar to front-end)

Deleting TLS policy
As usual, preceded by confirmation. Policy that is used by VIP listener(s) can not be deleted

Updating TLS policy

 * Only front-end and back-end protocols and cipher suite groups may be modified
 * Changing front-end offloading and back-end re-encryption functionality is not supported

Note: If changed policy is associated with VIP listener(s), each back-end service provider should perform any required changes

VIP listener creation
VIP listener has currently 3 protocols for choice (HTTP, HTTPS, TCP) New protocol is proposed - TLS, which will be used to address cases of front end or/and back end encryption using certificates and policies.

VIP listener creation scenarios for TLS
By default, no TLS policy association required, default policy behavior described in overview section will take place. Tenant may associate TLS policy in order to get different behavior, but does not have to. Tenant must supply a default TLS certificate for front-end offloading if policy enabled front-end offloading. Tenant may supply a list of TLS certificates for SNI as well, but does not have to.

Proposal for SNI certificates specifying and its treating by LBaaS provider
1. Ordered list of certificates.

Tenant will create list of TLS certificates and be able to control its order.

Choosing TLS certificate for incoming traffic offload will be done in following steps (until the first match):


 * Scan the list, from first to last (top->bottom) and check if domain name exactly matches certificate's host name
 * Scan the list, from first to last (top->bottom) and check if domain name matches certificate's host name regex
 * Scan the list, from first to last (top->bottom) and check if domain name matches one of certificate's alternative host names
 * No matches found? - use default certificate

2. List of certificates

Tenant will create list of TLS certificates.


 * Choosing TLS certificate for incoming traffic offload will be done by scanning the list until the first match
 * No matches found? - use default certificate

3. List of (Certificate, list of (host names/patterns)): Example: ( (amazon_cert_id, [*amazon.com, *amazon1.com]), (acme_cert_id, [acme.com]) )

Tenant will create entries of TLS certificate and list of host name/s or host name patterns for this specific certificate.

Choosing TLS certificate for incoming traffic offload will be done in following steps (until the first match):

Note: this can not be supported by Radware LBaaS provider
 * Scan the list, from first to last (top->bottom) and check if domain name matches one of host names/patterns
 * No matches found? - use default certificate

VIP listener (with TLS protocol) updating
different policy may specify different behavior for front-end offloading and/or back-end re-encryption. This will require radical re-configuration of provider's back-end system, which seems to be not justified for this use case. Tenant, probably, should create new VIP listener with different TLS front-end offloading and back-end re-encryption settings.
 * TLS policy and certificates settings are available only for VIP listeners having TLS as a protocol
 * Changing TLS Policy for existing VIP listener is proposed to be deprecated because

API change

 * TLS policies CRUD will be added to LBaaS plugin API
 * Since TLS offload functionality is a core LBaaS capability, VIP listener TLS settings API will be merged into the existing LBaaS plugin API

Resources change

 * VIP listener resource will be modified with new:
 * TLS policy (optional)
 * Default TLS certificate (optional)
 * Associations link to SNI certificates list - SNI certificates will be saved in new associations table


 * TLS policy (new entity)
 * front-end-offloading : bool
 * front-end-protocols : list of comma-separated values from a list of allowed values (SSLv3, TLSv1, TLSv1.2), default=None
 * front-end-cipher_suites : list of coma-separated values
 * Format - __ _
 * back-end-encryption : bool
 * back-end-protocols :
 * back-end-cipher_suites :

Data model change

 * VIP listener entity will be modified with new optional TLS policy and TLS default certificate fields.
 * tls_policy_id (string 36)
 * default_tls-certificate_id (string 36) - Barbican's certificate container id


 * tls_policy (new table)
 * tls_policy_id (string 36)
 * tls_policy_name (string 64)
 * tls_policy_description (string 256)
 * front_end_offloading (bool)
 * front_end_protocols (string 32)
 * front_end_cipher_suites (string 512)
 * back_end_encryption_enabled (bool)
 * back_end_protocols (string 32)
 * back_end_cipher_suites (string 512)


 * vip_listener_sni_certificate_assoc - N:M (new associations table)
 * vip_listener_id (string 36)
 * tls_certificate_id (string 36)

DB Migration
DB migration is needed for:
 * VIP listener new columns - existing rows will be filled by null
 * New table for TLS policies
 * New table for SNI certificates associations to VIP listeners

CLI examples

 * VIP listener creation with TLS protocol (default behavior)

lb-vip-listener-create --subnet-id  --protocol TLS --protocol-port 443 --tls_default_certificate  --name [--address ] ...


 * VIP listener creation with TLS protocol and SNI certificates list (with TLS policy, front-end offloading enabled, back-end re-encryption enabled)

lb-vip-listener-create --subnet-id  --protocol TLS --protocol-port 443 --tls_policy policy_with_front_end_offloading_enabled_id --tls_default_certificate  --tls_sni_certificates certificate_1, certificate_2, certificate_3 --name [--address ] ...


 * VIP listener creation with TLS protocol (with TLS policy, front-end offloading disabled, back-end re-encryption enabled)

lb-vip-listener-create --subnet-id  --protocol TLS --protocol-port 443 --tls_policy policy_with_front_end_offloading_disabled_id --name [--address ] ...

lb-tls-policy-create --front-end-termination type=dict enabled=true protocols=SSLv3,TLSv1,TLSv1.2 cipher-suites=DES-CBC-SHA,EXP-DES-CBC-SHA, ... --back-end-termination  type=dict enabled=true protocols=SSLv3,TLSv1,TLSv1.2 cipher-suites=DES-CBC-SHA,EXP-DES-CBC-SHA, ... MY_POLICY
 * TLS policy creation (both, front-end offloading and back-end re-encryption enabled)

lb-tls-policy-update''' --policy_id MY_POLICY_ID --front-end-termination type-dict protocols=TLSv1,TLSv1.2 --back-end-termination type=dict protocols=TLSv1,TLSv1.1
 * Updating MY_POLICY policy with different protocols (no SSLv3)

lb-tls-policy-delete''' --policy_id MY_POLICY_ID
 * Deleting MY_POLICY

lb-tls-policy-list'''
 * Listing policies

lb-tls-policy-show''' --policy_id
 * Showing policy

TLS certificates management will be available via Barbican CLI



Implementation Plan

 * Creating new extension called "tls" with new TLS entities
 * implement new TLS policy CRUD API to the LBaaS Plugin
 * Implement changes in DB schema
 * Implement unit testing for new TLS extension's resources
 * Implement unit testing for new TLS DB mixin
 * Make integration with Barbican certificates storage API
 * Modifying LBaaS HA-Proxy driver to support TLS extension
 * Update HA-Proxy to version 1.5 {TBD}