Enable TLS inspection

This page describes how to enable Transport Layer Security (TLS) inspection for your Secure Web Proxy instance.

Before you begin

Before you configure Secure Web Proxy for TLS inspection, complete the tasks in the following sections.

Enable CAS

Secure Web Proxy uses Certificate Authority Service (CAS) to generate the certificates used for TLS inspection.

To enable CAS, use the following command:

  gcloud services enable privateca.googleapis.com

Create a CA pool

You must create a certificate authority (CA) pool before you can use CAS to create a CA. This section walks you through the permissions that you need to complete this task and then describes how to create a CA pool.

To generate certificates, TLS inspection uses a separate service account for each project called service-{project ID}@gcp-sa-certmanager.iam.gserviceaccount.com. Make sure that you have granted permissions to this service account to use your CA pool. If this access is revoked, TLS inspection stops working.

To create the pool, use the gcloud privateca pools create command and specify the subordinate pool ID, tier, project ID, and location.

gcloud privateca pools create SUBORDINATE_POOL_ID \
    --tier=TIER \
    --project=PROJECT_ID \
    --location=REGION

Replace the following:

  • SUBORDINATE_POOL_ID: the name of the CA pool

  • TIER: the CA tier, either devops or enterprise

    We recommend that you create the CA pool in the devops tier because tracking individually issued certificates is unnecessary.

  • PROJECT_ID: the ID of the CA pool project

  • REGION: the location of the CA pool

Create a subordinate CA pool

You can create a subordinate CA pool, and the root CA signs all of the CAs in that pool. These certificates are used to sign server certificates generated for TLS inspection.

To create a subordinate pool, use any of the following methods.

Create a subordinate CA pool by using an existing root CA stored within CAS

To generate a subordinate CA, do the following:

  1. Create a CA pool.
  2. Create subordinate CAs within a CA pool.

Create a subordinate CA pool by using an existing root CA held externally

To generate a subordinate CA, do the following:

  1. Create a CA pool.
  2. Create subordinate CAs signed by an external root CA.

Create a root CA

If you do not have an existing root CA, you can create one within CAS. To create a root CA, do the following:

  1. Create a root CA.
  2. Follow the steps in Create a subordinate CA pool by using an existing root CA stored within CAS.

For more information about CA pools, see the Certificate Authority Service documentation.

Create a service account

If you do not have a service account, you must create one and grant the required permissions.

  1. Create a service account:

    gcloud beta services identity create \
    --service=networksecurity.googleapis.com \
    --project=PROJECT_ID

    In response, the Google Cloud CLI creates a service account called service-{project ID}@gcp-sa-networksecurity.iam.gserviceaccount.com.

  2. For the service account that you created, grant permissions to generate certificates with your CA pool:

    gcloud privateca pools add-iam-policy-binding CA_POOL \
    --member='serviceAccount:SERVICE_ACCOUNT' \
    --role='roles/privateca.certificateManager' \
    --location='REGION'

Configure Secure Web Proxy for TLS inspection

You can only proceed with the tasks in this section after you have completed the prerequisite tasks listed in the Before you begin section.

To configure TLS inspection, complete the tasks in the following sections.

Create a TLS inspection policy

  1. Create the file TLS_INSPECTION_FILE.yaml. Replace TLS_INSPECTION_FILE with your desired filename.

  2. Add the following code to the YAML file to configure the desired TlsInspectionPolicy:

    name: projects/PROJECT_ID/locations/REGION/tlsInspectionPolicies/TLS_INSPECTION_NAME
caPool: projects/PROJECT_ID/locations/REGION/caPools/CA_POOL

    Replace the following:

    • PROJECT_ID: the project number
    • REGION: the region to create the policy in
    • TLS_INSPECTION_NAME: the name of the Secure Web Proxy TLS inspection policy

    • CA_POOL: the name of the CA pool to create the certificates from

      The CA pool must exist within the same region.

Import the TLS inspection policy

Import the TLS inspection policy that you created in the previous step:

gcloud network-security tls-inspection-policies import TLS_INSPECTION_NAME \
  --source=TLS_INSPECTION_FILE.yaml \
  --location=REGION

Add the TLS inspection policy to the security policy

Console

Create the web proxy policy

  1. In the Google Cloud console, go to the Network Security page.

    Go to Network Security

  2. Click Secure Web Proxy.

  3. Click the Policies tab.

  4. Click Create a policy.

  5. Enter a name for the policy that you want to create, such as myswppolicy.

  6. Enter a description of the policy, such as My new swp policy.

  7. In the Regions list, select the region where you want to create the Secure Web Proxy policy.

  8. To configure TLS inspection, select Configure TLS inspection.

  9. In the TLS inspection policy list, select the TLS inspection policy that you created.

  10. If you want to create rules for your policy, click Continue, and then click Add rule. For details, see Create Secure Web Proxy rules.

  11. Click Create.

Create the web proxy rules

  1. In the Google Cloud console, go to the Network Security page.

    Go to Network Security

  2. Click Secure Web Proxy.

  3. In the project selector menu, select your organization ID or the folder that contains your policy.

  4. Click the name of your policy.

  5. Click Add rule.

  6. Populate the rule fields:

    1. Name
    2. Description
    3. Status
    4. Priority: the numeric evaluation order of the rule. The rules are evaluated from highest to lowest priority where 0 is the highest priority.
    5. In the Action section, specify whether connections that match the rule are allowed (Allow) or denied (Deny).
    6. In the Session Match section, specify the criteria for matching the session. For more information about the syntax for SessionMatcher, see the CEL matcher language reference.
    7. To enable TLS inspection, select Enable TLS inspection.
    8. In the Application Match section, specify the criteria for matching the request. If you do not enable the rule for TLS inspection, then the request can only match HTTP traffic.
    9. Click Create.

  7. Click Add rule to add another rule.

  8. Click Create to create the policy.

Set up a web proxy

  1. In the Google Cloud console, go to the Network Security page.

    Go to Network Security

  2. Click Secure Web Proxy.

  3. Click the Web proxies tab.

  4. Click Set up a web proxy.

  5. Enter a name for the web proxy that you want to create, such as myswp.

  6. Enter a description of the web proxy, such as My new swp.

  7. In the Regions list, select the region where you want to create the web proxy.

  8. In the Network list, select the network where you want to create the web proxy.

  9. In the Subnetwork list, select the subnetwork where you want to create the web proxy.

  10. Enter the web proxy IP address.

  11. In the Certificate list, select the certificate that you want to use to create the web proxy.

  12. In the Policy list, select the policy that you created to associate the web proxy with.

  13. Click Create.

Cloud Shell

  1. Create the file policy.yaml:

      description: basic Secure Web Proxy policy
  name: projects/PROJECT_ID/locations/REGION/gatewaySecurityPolicies/policy1
  tlsInspectionPolicy: projects/PROJECT_ID/locations/REGION/tlsInspectionPolicies/TLS_INSPECTION_NAME

  2. Create the Secure Web Proxy policy:

      gcloud network-security gateway-security-policies import policy1 \
      --source=policy.yaml --location=REGION

  3. Create the file rule.yaml:

      name: projects/PROJECT_ID/locations/REGION/gatewaySecurityPolicies/policy1/rules/allow-example-com
  description: Allow example.com
  enabled: true
  priority: 1
  basicProfile: ALLOW
  sessionMatcher: host() == 'example.com'
  applicationMatcher: request.path.contains('index.html')
  tlsInspectionEnabled: true

  4. Create the security policy rule:

      gcloud network-security gateway-security-policies rules import allow-example-com \
      --source=rule.yaml \
      --location=REGION \
      --gateway-security-policy=policy1

  5. To attach a TLS inspection policy to an existing security policy, create the file POLICY_FILE.yaml. Replace POLICY_FILE with your desired filename.

      description: My Secure Web Proxy policy
  name: projects/PROJECT_ID/locations/REGION/gatewaySecurityPolicies/POLICY_NAME
  tlsInspectionPolicy: projects/PROJECT_ID/locations/REGION/tlsInspectionPolicies/TLS_INSPECTION_NAME

What's next?