Add apparmor support

ecs-init/apparmor/apparmor.go

@@ -17,8 +17,12 @@ const ecsDefaultProfile = `
 profile ecs-default flags=(attach_disconnected,mediate_deleted) {
   #include <abstractions/base>
 
-  network,
-  capability,
+  network inet, # Allow IPv4 traffic
+  network inet6, # Allow IPv6 traffic
+
+  capability net_admin, # Allow network configuration
+  capability sys_admin, # Allow ECS Agent to invoke the setns system call
+
   file,
   umount,
   # Host (privileged) processes may send signals to container processes.
@@ -52,18 +56,24 @@ profile ecs-default flags=(attach_disconnected,mediate_deleted) {
 }
 `
 
+var (
+	isProfileLoaded = isLoaded
+	loadPath        = load
+	createFile      = os.Create
+)
+
 // LoadDefaultProfile ensures the default profile to be loaded with the given name.
 // Returns nil error if the profile is already loaded.
 func LoadDefaultProfile(profileName string) error {
-	yes, err := isLoaded(profileName)
+	yes, err := isProfileLoaded(profileName)
 	if err != nil {
 		return err
 	}
 	if yes {
 		return nil
 	}
 
-	f, err := os.Create(filepath.Join(appArmorProfileDir, profileName))
+	f, err := createFile(filepath.Join(appArmorProfileDir, profileName))
 	if err != nil {
 		return err
 	}
@@ -74,8 +84,8 @@ func LoadDefaultProfile(profileName string) error {
 	}
 	path := f.Name()
 
-	if err := load(path); err != nil {
-		return fmt.Errorf("load apparmor profile %s: %w", path, err)
+	if err := loadPath(path); err != nil {
+		return fmt.Errorf("error loading apparmor profile %s: %w", path, err)
 	}
 	return nil
 }

ecs-init/apparmor/apparmor_test.go

@@ -0,0 +1,101 @@
+// Copyright 2015-2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"). You may
+// not use this file except in compliance with the License. A copy of the
+// License is located at
+//
+//     http://aws.amazon.com/apache2.0/
+//
+// or in the "license" file accompanying this file. This file 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.
+
+package apparmor
+
+import (
+	"errors"
+	"github.com/containerd/containerd/pkg/apparmor"
+	"github.com/stretchr/testify/require"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestLoadDefaultProfile(t *testing.T) {
+	testCases := []struct {
+		name             string
+		profileName      string
+		isLoadedResponse bool
+		isLoadedError    error
+		loadError        error
+		expectedError    error
+	}{
+		{
+			name:             "ProfileIsAlreadyLoaded",
+			profileName:      "testProfile.txt",
+			isLoadedResponse: true,
+			isLoadedError:    nil,
+			loadError:        nil,
+			expectedError:    nil,
+		},
+		{
+			name:             "ProfileNotLoaded",
+			profileName:      "testProfile.txt",
+			isLoadedResponse: false,
+			isLoadedError:    nil,
+			loadError:        nil,
+			expectedError:    nil,
+		},
+		{
+			name:             "IsLoadedError",
+			profileName:      "testProfile.txt",
+			isLoadedResponse: false,
+			isLoadedError:    errors.New("mock isLoaded error"),
+			loadError:        nil,
+			expectedError:    errors.New("mock isLoaded error"),
+		},
+		{
+			name:             "LoadProfileError",
+			profileName:      "testProfile.txt",
+			isLoadedResponse: false,
+			isLoadedError:    nil,
+			loadError:        errors.New("mock load error"),
+			expectedError:    errors.New("mock load error"),
+		},
+	}
+	defer func() {
+		isProfileLoaded = isLoaded
+		loadPath = load
+		createFile = os.Create
+	}()
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			if !apparmor.HostSupports() {
+				t.Skip()
+			}
+			tmpdir := os.TempDir()
+			filePath, err := os.MkdirTemp(tmpdir, "test")
+			require.NoError(t, err)
+			createFile = func(profileName string) (*os.File, error) {
+				f, err := os.Create(filepath.Join(filePath, tc.profileName))
+				return f, err
+			}
+			defer os.RemoveAll(filePath)
+			isProfileLoaded = func(profileName string) (bool, error) {
+				return tc.isLoadedResponse, tc.isLoadedError
+			}
+			loadPath = func(profile string) error {
+				return tc.loadError
+			}
+			err = LoadDefaultProfile(tc.profileName)
+			if tc.loadError == nil {
+				assert.Equal(t, tc.expectedError, err)
+			} else {
+				assert.Error(t, err)
+			}
+		})
+	}
+}

ecs-init/engine/engine.go

@@ -49,9 +49,13 @@ const (
 )
 
 // Injection point for testing purposes
-var getDockerClient = func() (dockerClient, error) {
-	return docker.Client()
-}
+var (
+	getDockerClient = func() (dockerClient, error) {
+		return docker.Client()
+	}
+	hostSupports       = ctrdapparmor.HostSupports
+	loadDefaultProfile = apparmor.LoadDefaultProfile
+)
 
 func dockerError(err error) error {
 	return engineError("could not create docker client", err)
@@ -198,9 +202,9 @@ func (e *Engine) PreStartGPU() error {
 // PreStartAppArmor sets up the ecs-default AppArmor profile if we're running
 // on an AppArmor-enabled system.
 func (e *Engine) PreStartAppArmor() error {
-	if ctrdapparmor.HostSupports() {
+	if hostSupports() {
 		log.Infof("pre-start: setting up %s AppArmor profile", apparmor.ECSDefaultProfileName)
-		return apparmor.LoadDefaultProfile(apparmor.ECSDefaultProfileName)
+		return loadDefaultProfile(apparmor.ECSDefaultProfileName)
 	}
 	return nil
 }

ecs-init/engine/engine_test.go

@@ -24,9 +24,13 @@ import (
 	"os"
 	"testing"
 
+	"github.com/aws/amazon-ecs-agent/ecs-init/apparmor"
 	"github.com/aws/amazon-ecs-agent/ecs-init/cache"
 	"github.com/aws/amazon-ecs-agent/ecs-init/gpu"
 	"github.com/golang/mock/gomock"
+	"github.com/stretchr/testify/assert"
+
+	ctrdapparmor "github.com/containerd/containerd/pkg/apparmor"
 )
 
 // getDockerClientMock backs up getDockerClient package-level function and replaces it with the mock passed as
@@ -584,3 +588,48 @@ func TestPostStopCredentialsProxyRouteRemoveError(t *testing.T) {
 		t.Errorf("engine post-stop error: %v", err)
 	}
 }
+
+func TestPreStartAppArmorSetup(t *testing.T) {
+	testCases := []struct {
+		name             string
+		hostSupports     bool
+		loadProfileError error
+		expectedError    error
+	}{
+		{
+			name:             "HostNotSupported",
+			hostSupports:     false,
+			loadProfileError: nil,
+			expectedError:    nil,
+		},
+		{
+			name:             "HostSupportedNoError",
+			hostSupports:     true,
+			loadProfileError: nil,
+			expectedError:    nil,
+		},
+		{
+			name:             "HostSupportedWithError",
+			hostSupports:     true,
+			loadProfileError: errors.New("error loading apparmor profile"),
+			expectedError:    errors.New("error loading apparmor profile"),
+		},
+	}
+	defer func() {
+		hostSupports = ctrdapparmor.HostSupports
+		loadDefaultProfile = apparmor.LoadDefaultProfile
+	}()
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			hostSupports = func() bool {
+				return tc.hostSupports
+			}
+			loadDefaultProfile = func(profile string) error {
+				return tc.loadProfileError
+			}
+			engine := &Engine{}
+			err := engine.PreStartAppArmor()
+			assert.Equal(t, tc.expectedError, err)
+		})
+	}
+}