Allow Filebeat modules to be excluded from FIPS-capable artifacts (#44920) (#45014)

* Add ability for Filebeat plugins (inputs) to specify that they should be excluded from FIPS builds

* Remove ExcludeForFIPS implementation

* Create and check FIPSAwareInput interface

* Make o365 input use FIPSAwareInput interface

* Running mage fmt

* Remove debugging statement

* Explain behavior for types not implementing the interface

* Adding godoc comments for implementations of the IsFIPSCapable() method

* Add unit test for checkFIPSCapability()

* Running mage fmt

* Remove example implementation

(cherry picked from commit 322d694)

Co-authored-by: Shaunak Kashyap <ycombinator@gmail.com>

Author: mergify[bot]

filebeat/beater/crawler.go

@@ -144,6 +144,10 @@ func (c *crawler) startInput(
 		inputRunner.Once = c.once
 	}
 
+	if err := checkFIPSCapability(runner); err != nil {
+		return err
+	}
+
 	c.inputs[id] = runner
 
 	c.log.Infof("Starting input (ID: %d)", id)

filebeat/beater/crawler_fips.go

@@ -0,0 +1,43 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. licenses this file to you under
+// the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+//go:build requirefips
+
+package beater
+
+import (
+	"fmt"
+
+	v2 "github.com/elastic/beats/v7/filebeat/input/v2"
+	"github.com/elastic/beats/v7/libbeat/cfgfile"
+)
+
+func checkFIPSCapability(runner cfgfile.Runner) error {
+	fipsAwareInput, ok := runner.(v2.FIPSAwareInput)
+	if !ok {
+		// Input is not FIPS-aware; assume it's FIPS capable and proceed
+		// without error
+		return nil
+	}
+
+	if fipsAwareInput.IsFIPSCapable() {
+		// Input is FIPS-capable, proceed without error
+		return nil
+	}
+
+	return fmt.Errorf("running a FIPS-capable distribution but input [%s] is not FIPS capable", runner.String())
+}

filebeat/beater/crawler_fips_test.go

@@ -0,0 +1,76 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. licenses this file to you under
+// the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+//go:build requirefips
+
+package beater
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/elastic/beats/v7/libbeat/cfgfile"
+)
+
+type fipsUnawareInput struct{}
+
+func newFIPSUnawareInput() *fipsUnawareInput { return &fipsUnawareInput{} }
+func (f *fipsUnawareInput) String() string   { return "fips_unaware_input" }
+func (f *fipsUnawareInput) Start()           {}
+func (f *fipsUnawareInput) Stop()            {}
+
+type fipsAwareInput struct{ isFIPSCapable bool }
+
+func newFIPSAwareInput(isFIPSCapable bool) *fipsAwareInput {
+	return &fipsAwareInput{isFIPSCapable: isFIPSCapable}
+}
+func (f *fipsAwareInput) String() string      { return "fips_aware_input" }
+func (f *fipsAwareInput) Start()              {}
+func (f *fipsAwareInput) Stop()               {}
+func (f *fipsAwareInput) IsFIPSCapable() bool { return f.isFIPSCapable }
+
+func TestCheckFIPSCapability(t *testing.T) {
+	tests := map[string]struct {
+		runner      cfgfile.Runner
+		expectedErr string
+	}{
+		"input_is_not_fips_aware": {
+			runner:      newFIPSUnawareInput(),
+			expectedErr: "",
+		},
+		"input_is_fips_aware_but_not_fips_capable": {
+			runner:      newFIPSAwareInput(false),
+			expectedErr: "running a FIPS-capable distribution but input [fips_aware_input] is not FIPS capable",
+		},
+		"input_is_fips_aware_and_fips_capable": {
+			runner:      newFIPSAwareInput(true),
+			expectedErr: "",
+		},
+	}
+
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) {
+			err := checkFIPSCapability(test.runner)
+			if test.expectedErr == "" {
+				require.NoError(t, err)
+			} else {
+				require.EqualError(t, err, test.expectedErr)
+			}
+		})
+	}
+}

filebeat/beater/crawler_nofips.go

@@ -0,0 +1,28 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. licenses this file to you under
+// the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+//go:build !requirefips
+
+package beater
+
+import "github.com/elastic/beats/v7/libbeat/cfgfile"
+
+func checkFIPSCapability(_ cfgfile.Runner) error {
+	// In non-FIPS builds, we assume all inputs are FIPS capable
+	// and proceed without error
+	return nil
+}

filebeat/input/v2/compat/compat.go

@@ -223,3 +223,14 @@ func (f *factory) generateCheckConfig(config *conf.C) (*conf.C, error) {
 
 	return testCfg, nil
 }
+
+// IsFIPSCapable returns true if the input is capable of running with
+// FIPS-compliant algorithms; false, otherwise.
+func (r *runner) IsFIPSCapable() bool {
+	if fipsAwareInput, ok := r.input.(v2.FIPSAwareInput); ok {
+		return fipsAwareInput.IsFIPSCapable()
+	}
+
+	// Input does not implement FIPSAwareInput, assume it is FIPS-capable
+	return true
+}

filebeat/input/v2/input-cursor/input.go

@@ -86,6 +86,15 @@ func (inp *managedInput) Test(ctx input.TestContext) error {
 	return nil
 }
 
+// IsFIPSCapable returns true if the input is capable of running with
+// FIPS-compliant algorithms; false, otherwise.
+func (inp *managedInput) IsFIPSCapable() bool {
+	if fipsAware, ok := inp.input.(input.FIPSAwareInput); ok {
+		return fipsAware.IsFIPSCapable()
+	}
+	return true
+}
+
 func (inp *managedInput) testSource(ctx input.TestContext, source Source) (err error) {
 	defer func() {
 		if v := recover(); v != nil {

filebeat/input/v2/input.go

@@ -78,6 +78,14 @@ type Input interface {
 	Run(Context, beat.PipelineConnector) error
 }
 
+// FIPSAwareInput is able to report if it is FIPS capable or not. If a type does
+// not implement this interface, that type will be considered to be FIPS capable.
+type FIPSAwareInput interface {
+	// IsFIPSCapable returns true if the input is capable of running with
+	// FIPS-compliant algorithms; false, otherwise.
+	IsFIPSCapable() bool
+}
+
 // Context provides the Input Run function with common environmental
 // information and services.
 type Context struct {