Fluentd filter plugin for Google Cloud Data Loss Prevention API

2019-03-12

This article describes using Fluentd filter plugin to sanitize logs using GCP DLP API. Specifically, this filter reads fluentd log records and redacts portiions that the DLP API detects that match the inputtypes configured.

Once the records data is redacted, fluent can forward the sanitized logs to whichever output filter that is configured (in the examples below, the output filter for Google Cloud Logging is shown.

NOTE this plugin (as of 2/25) will only deIdentify string_value types.

This plugin is NOT supported by google


You can find the source here


Plugin configuration

  • deidentify_template, :array, value_type: :string –> Reference to DLP deidentify template.
  • use_metadata_service, :bool, :default => false –> Use GCE metadata server to derive access_token and project_id
  • google_credential_file, :string, :default => nil -> Path to GCP json service account credential file.
  • project_id, :string, :default => nil –> Set project_id manually. Plugin will attempt to derive project_id from json credential file or GCE metadata.

Installation steps below describes setting this up on

  1. Plain fluentd on arbitrary platforms
  2. On GCE VM with metadata server and fluent-plugin-google-cloud outputs.

NOTE:

..some TODOs:


Installation

Build gem

Either build gem locally or download the one provided in this repo.

  • to build locally,
gem build fluent-plugin-gcp-dlp-filter.gemspec 
  Successfully built RubyGem
  Name: fluent-plugin-gcp-dlp-filter
  Version: 0.0.8
  File: fluent-plugin-gcp-dlp-filter-0.0.8.gem

Fluentd

This section covers running the dlp agent within a stand-alone docker image.

  • Create service account and private key (name the file as application_default_credential.json)
  • Assign DLP User, DLP De-identify Templates Reader, and Logging Writer IAM roles

images/dlp_iam.png

Create a DLP template. The example below uses a de-identify template that replaces an SSN

images/did_template.png

Copy the service account file to the volume mount in the container

mkdir certs
cp application_default_credential.json certs/
cp fluent-plugin-gcp-dlp-filter-0.0.8.gem certs/

docker run -ti  -p 8888:8888 -v `pwd`/certs/:/etc/google/auth/ debian /bin/bash

apt-get update
apt-get install -y curl sudo gnupg make gcc vim procps wget

curl -L https://toolbelt.treasuredata.com/sh/install-debian-stretch-td-agent3.sh | sh

# make sure the credential file is mapped correctly
mkdir -p /etc/google/auth/
chown td-agent:td-agent /etc/google/auth/application_default_credentials.json
chmod go-rwx /etc/google/auth/application_default_credentials.json
          

install the dlp gem:

# install dlp gem
/opt/td-agent/embedded/bin/gem install google-cloud-dlp   
/usr/sbin/td-agent-gem install --local  /etc/google/auth/fluent-plugin-gcp-dlp-filter-0.0.8.gem
  • edit /etc/td-agent/td-agent.conf

Specify the URL for the de-identify template and id you created earlier


<filter gcp_resource.**>
  @type gcp_dlp
  google_credential_file /etc/google/auth/application_default_credentials.json
  deidentify_template projects/your-project-id/deidentifyTemplates/templateid
</filter>

<filter  gcp_resource.**>
  @type stdout
</filter>

Note: please see the followign to configure the deidentify template

  • send traffic

curl -X POST -d 'json={"foo": "hi, my email is sal@domain.com and ssn is 223-22-2222"}' \
  http://localhost:8888/gcp_resource.log

Since the configuration above applies the output to /var/log/td-agent/td-agent.log, the log files will show:

2019-02-24 20:20:32.802290465 +0000 gcp_resource.log: 
   {"foo":"hi, my email is [EMAIL_ADDRESS] and ssn is [US_SOCIAL_SECURITY_NUMBER]"}

Fluentd with GCP Output

If you want to emit the logs to GCP from arbitrary, on-prem VMs, you can utilize genric_node and generic_task resource_types on Stackdriver. At the moment the google-plugin-google-cloud agent does not accept processing of this resource type. The sample provided in the fork below does include the supported code for this (note, this fork is not supported by google).

/opt/td-agent/embedded/bin/gem install google-cloud-dlp
/usr/sbin/td-agent-gem install --local  /etc/google/auth/fluent-plugin-gcp-dlp-filter-0.0.8.gem
# google-api-client version pinned due to conflict..fluent-plugin-google-cloud uses older google-api-client-0.23.9
/opt/td-agent/embedded/bin/gem install google-api-client -v 0.28.4
/opt/td-agent/embedded/bin/gem install fluent-plugin-google-cloud


wget https://raw.githubusercontent.com/salrashid123/fluent-plugin-google-cloud/master/lib/fluent/plugin/out_google_cloud.rb .

cp out_google_cloud.rb \
   /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluent-plugin-google-cloud-0.7.5/lib/fluent/plugin/out_google_cloud.rb
  • edit /etc/td-agent/td-agent.conf

add

<filter gcp_resource.**>
  @type record_transformer
  @log_level debug
  <record>
    "logging.googleapis.com/local_resource_id" "generic_node.us-central1-a.default.somehost"
  </record>
</filter>

<filter gcp_resource.**>
  @type gcp_dlp
  google_credential_file /etc/google/auth/application_default_credentials.json
  deidentify_template projects/your-project-id/deidentifyTemplates/templateId
</filter>

<filter  gcp_resource.**>
  @type stdout
</filter>

<match gcp_resource.**>
  @type google_cloud
  use_metadata_service false
  @log_level debug
</match>

(it will take a min or two to show up in GCP logs)

images/fluentd_gcp_log.png

GCP

You can also run the agent directly on a GCE VM with the Stackdriver Logging Agent:

  • Create a VM with full Cloud Platform Scope
  • Assign IAM roles to VM’s service account to DLP User and Logging Writer Roles

Install the agent:

curl -sSO "https://dl.google.com/cloudagents/install-logging-agent.sh"

sudo bash install-logging-agent.sh --structured

Install fluent-plugin-gcp-dlp-filter-0.0.8.gem

/opt/google-fluentd/embedded/bin/gem install google-cloud-dlp
wget https://github.com/salrashid123/fluent-plugin-gcp-dlp-filter/raw/master/fluent-plugin-gcp-dlp-filter-0.0.8.gem
/opt/google-fluentd/embedded/bin/gem install --local fluent-plugin-gcp-dlp-filter-0.0.8.gem

Yes, i didn’t add this yet to rubygems

Edit

  • /etc/google-fluentd/google-fluentd.conf

<source>
  @type http
  @id input_http
  port 8888
</source>

<filter gcp_resource.**>
  @type gcp_dlp
  deidentify_template projects/your-project=id/deidentifyTemplates/templateid
  use_metadata_service  true 
</filter>

<filter gcp_resource.**>
  @type stdout
</filter>

<match gcp_resource.**>
  @type google_cloud
  use_metadata_service true
  @log_level debug
</match>

Send traffic

curl -X POST -d 'json={"foo": "hi, my email is sal@domain.com and ssn is 223-22-2222"}' http://localhost:8888/gcp_resource.log

verify in /var/log/google-fluentd/google-fluentd.log

2019-02-24 23:01:30.903400079 +0000 gcp_resource.log: 
    {"foo":"hi, my email is [EMAIL_ADDRESS] and ssn is [US_SOCIAL_SECURITY_NUMBER]","logging.googleapis.com/insertId":"3jwayh9qo8vip9ba6"}

images/gcp_log.png

GCP Syslog

As with any other fluentd config, you can specify which sources to apply the filter against. For syslog on GCE, the config

<filter syslog**>
  @type gcp_dlp
  deidentify_template projects/your-project-id/deidentifyTemplates/templateid
  use_metadata_service  true 
</filter>

will apply the plugin to the syslog. If you emit a log line like

logger "hi sal my email is srashid@domain.com"

That will show up in GCP logs as:

images/syslog_dlp.png

Note: the source system will still include the unredacted log line (in this case the /var/log/syslog on the VM itself)

Testing

Note, current the test cases actually invokes the DLP API (even as test)!

Edit test/plugin/test_gcp_dlp.rb and update all the CONFIG* variables to point to an actual GCP certificate file as well as a reference to a deidentify Template on that project.

eg

  CONFIG = %[
    info_types ALL_BASIC
    google_credential_file /path/to/your/local/application_default_credentials.json
    use_metadata_service false
  ]
$ bundle exec ruby test/plugin/test_gcp_dlp.rb
Loaded suite test/plugin/test_gcp_dlp
Started
..
Finished in 1.042686837 seconds.
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
2 tests, 4 assertions, 0 failures, 0 errors, 0 pendings, 0 omissions, 0 notifications
100% passed
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1.92 tests/s, 3.84 assertions/s

References

  • Fluentd
  • DLP

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