helm-external-secrets/pkg/provider/aws/secretsmanager/secretsmanager.go

/*
Licensed 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.
*/

package secretsmanager

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"regexp"

	utilpointer "k8s.io/utils/pointer"

	"github.com/aws/aws-sdk-go/aws/session"
	awssm "github.com/aws/aws-sdk-go/service/secretsmanager"
	"github.com/tidwall/gjson"
	ctrl "sigs.k8s.io/controller-runtime"

	esv1beta1 "github.com/external-secrets/external-secrets/apis/externalsecrets/v1beta1"
	"github.com/external-secrets/external-secrets/pkg/find"
	"github.com/external-secrets/external-secrets/pkg/provider/aws/util"
)

// SecretsManager is a provider for AWS SecretsManager.
type SecretsManager struct {
	sess   *session.Session
	client SMInterface
	cache  map[string]*awssm.GetSecretValueOutput
}

// SMInterface is a subset of the smiface api.
// see: https://docs.aws.amazon.com/sdk-for-go/api/service/secretsmanager/secretsmanageriface/
type SMInterface interface {
	GetSecretValue(*awssm.GetSecretValueInput) (*awssm.GetSecretValueOutput, error)
	ListSecrets(*awssm.ListSecretsInput) (*awssm.ListSecretsOutput, error)
}

const (
	errUnexpectedFindOperator = "unexpected find operator"
	errDuplicateKey           = "duplicate key mapping at %s"
)

var log = ctrl.Log.WithName("provider").WithName("aws").WithName("secretsmanager")

// New creates a new SecretsManager client.
func New(sess *session.Session) (*SecretsManager, error) {
	return &SecretsManager{
		sess:   sess,
		client: awssm.New(sess),
		cache:  make(map[string]*awssm.GetSecretValueOutput),
	}, nil
}

func (sm *SecretsManager) fetch(_ context.Context, ref esv1beta1.ExternalSecretDataRemoteRef) (*awssm.GetSecretValueOutput, error) {
	ver := "AWSCURRENT"
	if ref.Version != "" {
		ver = ref.Version
	}
	log.Info("fetching secret value", "key", ref.Key, "version", ver)

	cacheKey := fmt.Sprintf("%s#%s", ref.Key, ver)
	if secretOut, found := sm.cache[cacheKey]; found {
		log.Info("found secret in cache", "key", ref.Key, "version", ver)
		return secretOut, nil
	}
	secretOut, err := sm.client.GetSecretValue(&awssm.GetSecretValueInput{
		SecretId:     &ref.Key,
		VersionStage: &ver,
	})
	if err != nil {
		return nil, err
	}
	sm.cache[cacheKey] = secretOut

	return secretOut, nil
}

// Empty GetAllSecrets.
func (sm *SecretsManager) GetAllSecrets(ctx context.Context, ref esv1beta1.ExternalSecretFind) (map[string][]byte, error) {
	if ref.Name != nil {
		return sm.findByName(ctx, ref)
	}
	if len(ref.Tags) > 0 {
		return sm.findByTags(ctx, ref)
	}
	return nil, errors.New(errUnexpectedFindOperator)
}

func (sm *SecretsManager) findByName(ctx context.Context, ref esv1beta1.ExternalSecretFind) (map[string][]byte, error) {
	matcher, err := find.New(*ref.Name)
	if err != nil {
		return nil, err
	}
	data := make(map[string][]byte)
	var nextToken *string

	for {
		ctrl.Log.Info("aws sm findByName", "nextToken", nextToken)
		it, err := sm.client.ListSecrets(&awssm.ListSecretsInput{
			NextToken: nextToken,
		})
		if err != nil {
			return nil, err
		}
		ctrl.Log.Info("aws sm findByName found", "secrets", len(it.SecretList))
		for _, secret := range it.SecretList {
			if !matcher.MatchName(*secret.Name) {
				continue
			}
			ctrl.Log.Info("aws sm findByName matches", "name", *secret.Name)
			err = sm.fetchAndSet(ctx, data, *secret.Name)
			if err != nil {
				return nil, err
			}
		}
		nextToken = it.NextToken
		if nextToken == nil {
			break
		}
	}
	return data, nil
}

func (sm *SecretsManager) findByTags(ctx context.Context, ref esv1beta1.ExternalSecretFind) (map[string][]byte, error) {
	filters := make([]*awssm.Filter, len(ref.Tags)*2)
	for k, v := range ref.Tags {
		filters = append(filters, &awssm.Filter{
			Key: utilpointer.StringPtr(awssm.FilterNameStringTypeTagKey),
			Values: []*string{
				utilpointer.StringPtr(k),
			},
		}, &awssm.Filter{
			Key: utilpointer.StringPtr(awssm.FilterNameStringTypeTagValue),
			Values: []*string{
				utilpointer.StringPtr(v),
			},
		})
	}

	data := make(map[string][]byte)
	var nextToken *string
	for {
		ctrl.Log.Info("aws sm findByTag", "nextToken", nextToken)
		it, err := sm.client.ListSecrets(&awssm.ListSecretsInput{
			Filters:   filters,
			NextToken: nextToken,
		})
		if err != nil {
			return nil, err
		}
		ctrl.Log.Info("aws sm findByTag found", "secrets", len(it.SecretList))
		for _, secret := range it.SecretList {
			err = sm.fetchAndSet(ctx, data, *secret.Name)
			if err != nil {
				return nil, err
			}
		}
		nextToken = it.NextToken
		if nextToken == nil {
			break
		}
	}
	return data, nil
}

func (sm *SecretsManager) fetchAndSet(ctx context.Context, data map[string][]byte, name string) error {
	ctrl.Log.Info("aws sm fetchAndSet fetch", "name", name)
	sec, err := sm.fetch(ctx, esv1beta1.ExternalSecretDataRemoteRef{
		Key: name,
		// Right now we only support AWSCURRENT as version
		// There is no intent to support specific versions
		// or specific aliases like AWSPREVIOUS or AWSPENDING
		Version: "AWSCURRENT",
	})
	if err != nil {
		return err
	}

	// Note: multiple key names can collide:
	//       foo/bar and foo$bar would result in the same key
	//       foo_bar being mapped.
	key := mapSecretKey(name)
	if _, exist := data[key]; exist {
		return fmt.Errorf(errDuplicateKey, key)
	}

	if sec.SecretString != nil {
		data[key] = []byte(*sec.SecretString)
	}
	if sec.SecretBinary != nil {
		data[key] = sec.SecretBinary
	}
	return nil
}

var keyChars = regexp.MustCompile(`[^A-Za-z0-9_\-.]+`)

func mapSecretKey(key string) string {
	return keyChars.ReplaceAllString(key, "_")
}

// GetSecret returns a single secret from the provider.
func (sm *SecretsManager) GetSecret(ctx context.Context, ref esv1beta1.ExternalSecretDataRemoteRef) ([]byte, error) {
	secretOut, err := sm.fetch(ctx, ref)
	if err != nil {
		return nil, util.SanitizeErr(err)
	}
	if ref.Property == "" {
		if secretOut.SecretString != nil {
			return []byte(*secretOut.SecretString), nil
		}
		if secretOut.SecretBinary != nil {
			return secretOut.SecretBinary, nil
		}
		return nil, fmt.Errorf("invalid secret received. no secret string nor binary for key: %s", ref.Key)
	}
	var payload string
	if secretOut.SecretString != nil {
		payload = *secretOut.SecretString
	}
	if secretOut.SecretBinary != nil {
		payload = string(secretOut.SecretBinary)
	}

	val := gjson.Get(payload, ref.Property)
	if !val.Exists() {
		return nil, fmt.Errorf("key %s does not exist in secret %s", ref.Property, ref.Key)
	}
	return []byte(val.String()), nil
}

// GetSecretMap returns multiple k/v pairs from the provider.
func (sm *SecretsManager) GetSecretMap(ctx context.Context, ref esv1beta1.ExternalSecretDataRemoteRef) (map[string][]byte, error) {
	log.Info("fetching secret map", "key", ref.Key)
	data, err := sm.GetSecret(ctx, ref)
	if err != nil {
		return nil, err
	}
	kv := make(map[string]json.RawMessage)
	err = json.Unmarshal(data, &kv)
	if err != nil {
		return nil, fmt.Errorf("unable to unmarshal secret %s: %w", ref.Key, err)
	}
	secretData := make(map[string][]byte)
	for k, v := range kv {
		var strVal string
		err = json.Unmarshal(v, &strVal)
		if err == nil {
			secretData[k] = []byte(strVal)
		} else {
			secretData[k] = v
		}
	}
	return secretData, nil
}

func (sm *SecretsManager) Close(ctx context.Context) error {
	return nil
}

func (sm *SecretsManager) Validate() error {
	_, err := sm.sess.Config.Credentials.Get()
	return err
}