Bug Reference

CLOUDSTACK-4821

Introduction

SSL Offloading feature allows loadbalancers to handle encryption/decryption of HTTP(s) traffic giving plaintext HTTP to the backend servers freeing them from the resource intensive task of handling encryption/decryption. Major loadblancers like the Netscaler and F5 have this functionality. This document is a functional sepc for adding certificate mangaement and implementing SSL offload capability for cloudstack provisioned loadbalancers.

Goals

1. A user should be able to create/update/delete SSL certs for his account.
2. Certificates can be searched by using either the certificate ID or the account ID.
3. Attach/Remove a certificate from a loadbalancers which support SSL offload feature.
4. Add support for Netscaler to use this feature.

References

• http://support.citrix.com/proddocs/topic/netscaler/ns-ssl-wrapper-con-92.html
• AWS API for Upload, Delete, List, Update SSL Certificates.
• AWS API for assigning certificate to LB , Updating certificate for a LB and Unset certificate from LB, but does not work
• StackOverflow thread for the unset SSL certificate issue in AWS.

Document History

Functional requirements & non-requirements

1. Introduce a new entity SSLCerts linked to a user account
2. Users should be able to Add/Delete/List certificates linked to their account
3. Admin should be able to list all the certificates for all accounts
4. When creating a loadbalancer if the public port is 443 and the private port is 80, then
   • If the loadbalancer device supports SSL offloading,
     • The loadbalncer created should be of type SSL.
     • Should allow attach/remove of a SSL certificate to it.
   • If the loadbalancer device does not support ssl offload,
     • The loadbalancer type will be TCP.
     • Trying to attach a certificate to it should generate an error
5. Users should be able to attach/remove their certificates to their loadbalancers.
6. Deleting a SSL certificate should also remove it from all the loadbalancers it is attached to.
7. If a user account gets deleted, the associated Certificates should also be deleted.
8. If a loadbalancer gets deleted, the associated binding should also be deleted.
9. The private key and password for the key should be stored encrypted

Architecture and Design description

Assumtions

• The SSL certificates should include the chain trust with them. They are added to the device as-is.
• For the netscaler loadbalancer, we assume that the port 22 is open and there is space in /nsconfig as we scp the certificate to the device.
• A loadbalancer rule can have only one certificate attached to it. A certificate however can be attached to multiple loadbalancers ( As long they are SSL type ). Support for multiple certificates for a single loadbalancer is not scoped.
• The certificate is not checked for validity at cloudstack level. The device errors if the certificate is invalid

Design

General Flow

• when calling AssignToLoadBalancerRule if there is a certificate id in the request execute() method of the command calls
  assignSslCertToLoadBalancer(lb_id, certId) in LoadBalancingRulesManagerImpl
• assignSslCertToLoadBalancer checks if the loadbalancer is capable of SSL. If not error is returned.
• verify if other certificate is bound to the loadbalancer and if it is, return error
• It then verifies if the certificate is valid ( not revoked ) and creates an entry in the load_balancer_cert_map table
• the loadbalncer state is set to Add
• call the applyLoadBalancerConfig which calls applyLoadBalancerRules with the lbId
• getLoadBalancerRuleToApply function should also add getSslCertificates(lbId) which gets called from applyLoadBalancerConfig
• Now the rule has SSL certificate info as well.
• When the rules get applied by calling applyLBRules of the NetscalerElement, the SSL info is passed inside the rule.
• NetscalerElement creates a LoadBalancerTO which transfers the params to the resouce layer.
• The LoadBalancerTO should contain SslCertTO for holding certificate information.

• The SSL offload will be defined as a Capability in as SSL
• NetscalerElement when checking for canHandleLbRules will check for SSL rule and respond accordingly
• LoadBalancingRule will have a new static class LbSslCert and will have a list List<LbSslCert> for holding the certificate(s)
• LoadBalancerTO will have a new parameter for passing certificate information.
  LoadBalancingRule.java

  // rule for SSL certificates
  public class LoadBalancingRule { 
   ....
  
    public static class LbSslCert()
    {
      String cert;
      String key;
      String password;
      boolean _revoke;
  
      public LbSslCert(cert,key,password) {}
    
    }
  
    public void setSslCerts(List<SslCert> certs){}
    public void setSslCerts(List<SslCert> certs){}
  ...
  }
  

New tables

ssl_certs(id, uuid, account_id, cert, key, password)

load_balancer_cert_map(id, load_balancer_id, cert_id, revoke, state)

New Webservice APIs for Certificate Management

This section lists the new webservice APIs for Certificate management. They are derived from their AWS Equivalant ( UploadServerCertificate, ListServerCertificates, GetServerCertificate, DeleteServerCertificate )

uploadSSLCert

Uploads a new SSL certificate-key pair

Request parameters:

• cert : Required : The public certificate, should also include the trust chain if required
• key : Required : The private key for the certificate, if the key is encrypted, password should be provided
• password: Optional : The password for the private key

Response parameters:

• id : The ID of the certificate
• account : The account of the SSL certificate
• cert : public certificate
• key : private key

deleteSSLCert

Deletes an existing SSL cert from cloudstack.

Request parameters:

• id : Required : The id of the certificate

Response parameters:

• displaytext : any text associated with the success or failure
• success : true if operation is executed successfully

updateSSLCert

updates an existing certificate-key pair

Request parameters:

• id : Required: The id of the certificate
• cert : Optional : The public certificate, should also include the trust chain if required
• key : Optional : The private key for the certificate, if the key is encrypted, password should be provided
• password: Optional : The password for the private key

Response parameters:

• id : The id of the certificate
• cert : The public certificate, should also include the trust chain if required
• key : The private key for the certificate, if the key is encrypted, password should be provided

listSSLCerts

lists the certificates for an Id or an account

Request parameters:

• id : Optional : The id of the certificate
• accountid : Optional : The account id for which the certs are to be listed
• lbruleid : Optional : The load balancer rule to list the certificate for

Response parameters:

The response is a list of following

• id : The id of the certificate
• cert : The public certificate, should also include the trust chain if required
• key : The private key for the certificate, if the key is encrypted, password should be provided
• account : Account associated with the certificate
• lbruleid : The lb rule associated with the certificate

New parameters to loadbalancing APIs

For associating the certificates to loadbalancing rules, we need to add the certificate id parameter to following loadbalancer apis.

assignToLoadBalancerRule

Request parameter to be added:

• certificateid: Optional : The id of the certificate to assign to this rule.

removeFromLoadBalancerRule

Request parameter to be added:

• certificateid: Optional : The id of the certificate to remove from this rule.

UI flow

Right now, this feature will only be available via the API. UI support is not yet scoped.

IP Clearance

No external dependecies are being added for this feature. All code will be developed within Cloudstack’s scope.