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Merge pull request #3516 from crosbymichael/remote-enc

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Remove encryption code from containerd core
This commit is contained in:
Phil Estes
2019-08-13 10:52:48 -04:00
committed by GitHub
parent 95277fa447 d085d9b464
commit b77e25dade
101 changed files with 0 additions and 27005 deletions
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429
images/encryption/encryption.go
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@@ -1,429 +0,0 @@
/*
Copyright The containerd Authors.
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 encryption
import (
"bytes"
"context"
"encoding/json"
"fmt"
"io"
"math/rand"
"github.com/containerd/containerd/images"
"github.com/containerd/containerd/pkg/encryption"
encconfig "github.com/containerd/containerd/pkg/encryption/config"
"github.com/containerd/containerd/content"
"github.com/containerd/containerd/errdefs"
"github.com/containerd/containerd/platforms"
digest "github.com/opencontainers/go-digest"
specs "github.com/opencontainers/image-spec/specs-go"
"github.com/pkg/errors"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
)
type cryptoOp int
const (
cryptoOpEncrypt cryptoOp = iota
cryptoOpDecrypt = iota
cryptoOpUnwrapOnly = iota
)
// LayerFilter allows to select Layers by certain criteria
type LayerFilter func(desc ocispec.Descriptor) bool
// IsEncryptedDiff returns true if mediaType is a known encrypted media type.
func IsEncryptedDiff(ctx context.Context, mediaType string) bool {
switch mediaType {
case images.MediaTypeDockerSchema2LayerGzipEnc, images.MediaTypeDockerSchema2LayerEnc:
return true
}
return false
}
// HasEncryptedLayer returns true if any LayerInfo indicates that the layer is encrypted
func HasEncryptedLayer(ctx context.Context, layerInfos []ocispec.Descriptor) bool {
for i := 0; i < len(layerInfos); i++ {
if IsEncryptedDiff(ctx, layerInfos[i].MediaType) {
return true
}
}
return false
}
// encryptLayer encrypts the layer using the CryptoConfig and creates a new OCI Descriptor.
// A call to this function may also only manipulate the wrapped keys list.
// The caller is expected to store the returned encrypted data and OCI Descriptor
func encryptLayer(cc *encconfig.CryptoConfig, dataReader content.ReaderAt, desc ocispec.Descriptor) (ocispec.Descriptor, io.Reader, error) {
var (
size int64
d digest.Digest
err error
)
encLayerReader, annotations, err := encryption.EncryptLayer(cc.EncryptConfig, encryption.ReaderFromReaderAt(dataReader), desc)
if err != nil {
return ocispec.Descriptor{}, nil, err
}
// were data touched ?
if encLayerReader != nil {
size = 0
d = ""
} else {
size = desc.Size
d = desc.Digest
}
newDesc := ocispec.Descriptor{
Digest: d,
Size: size,
Platform: desc.Platform,
Annotations: annotations,
}
switch desc.MediaType {
case images.MediaTypeDockerSchema2LayerGzip:
newDesc.MediaType = images.MediaTypeDockerSchema2LayerGzipEnc
case images.MediaTypeDockerSchema2Layer:
newDesc.MediaType = images.MediaTypeDockerSchema2LayerEnc
case images.MediaTypeDockerSchema2LayerGzipEnc:
newDesc.MediaType = images.MediaTypeDockerSchema2LayerGzipEnc
case images.MediaTypeDockerSchema2LayerEnc:
newDesc.MediaType = images.MediaTypeDockerSchema2LayerEnc
// TODO: Mediatypes to be added in ocispec
case ocispec.MediaTypeImageLayerGzip:
newDesc.MediaType = images.MediaTypeDockerSchema2LayerGzipEnc
case ocispec.MediaTypeImageLayer:
newDesc.MediaType = images.MediaTypeDockerSchema2LayerEnc
default:
return ocispec.Descriptor{}, nil, errors.Errorf("Encryption: unsupporter layer MediaType: %s\n", desc.MediaType)
}
return newDesc, encLayerReader, nil
}
// decryptLayer decrypts the layer using the CryptoConfig and creates a new OCI Descriptor.
// The caller is expected to store the returned plain data and OCI Descriptor
func decryptLayer(cc *encconfig.CryptoConfig, dataReader content.ReaderAt, desc ocispec.Descriptor, unwrapOnly bool) (ocispec.Descriptor, io.Reader, error) {
resultReader, d, err := encryption.DecryptLayer(cc.DecryptConfig, encryption.ReaderFromReaderAt(dataReader), desc, unwrapOnly)
if err != nil || unwrapOnly {
return ocispec.Descriptor{}, nil, err
}
newDesc := ocispec.Descriptor{
Digest: d,
Size: 0,
Platform: desc.Platform,
}
switch desc.MediaType {
case images.MediaTypeDockerSchema2LayerGzipEnc:
newDesc.MediaType = images.MediaTypeDockerSchema2LayerGzip
case images.MediaTypeDockerSchema2LayerEnc:
newDesc.MediaType = images.MediaTypeDockerSchema2Layer
default:
return ocispec.Descriptor{}, nil, errors.Errorf("Decryption: unsupporter layer MediaType: %s\n", desc.MediaType)
}
return newDesc, resultReader, nil
}
// cryptLayer handles the changes due to encryption or decryption of a layer
func cryptLayer(ctx context.Context, cs content.Store, desc ocispec.Descriptor, cc *encconfig.CryptoConfig, cryptoOp cryptoOp) (ocispec.Descriptor, error) {
var (
resultReader io.Reader
newDesc ocispec.Descriptor
)
dataReader, err := cs.ReaderAt(ctx, desc)
if err != nil {
return ocispec.Descriptor{}, err
}
defer dataReader.Close()
if cryptoOp == cryptoOpEncrypt {
newDesc, resultReader, err = encryptLayer(cc, dataReader, desc)
} else {
newDesc, resultReader, err = decryptLayer(cc, dataReader, desc, cryptoOp == cryptoOpUnwrapOnly)
}
if err != nil || cryptoOp == cryptoOpUnwrapOnly {
return ocispec.Descriptor{}, err
}
// some operations, such as changing recipients, may not touch the layer at all
if resultReader != nil {
var ref string
// If we have the digest, write blob with checks
haveDigest := newDesc.Digest.String() != ""
if haveDigest {
ref = fmt.Sprintf("layer-%s", newDesc.Digest.String())
} else {
ref = fmt.Sprintf("blob-%d-%d", rand.Int(), rand.Int())
}
if haveDigest {
if err := content.WriteBlob(ctx, cs, ref, resultReader, newDesc); err != nil {
return ocispec.Descriptor{}, errors.Wrap(err, "failed to write config")
}
} else {
newDesc.Digest, newDesc.Size, err = ingestReader(ctx, cs, ref, resultReader)
if err != nil {
return ocispec.Descriptor{}, err
}
}
}
return newDesc, err
}
func ingestReader(ctx context.Context, cs content.Ingester, ref string, r io.Reader) (digest.Digest, int64, error) {
cw, err := content.OpenWriter(ctx, cs, content.WithRef(ref))
if err != nil {
return "", 0, errors.Wrap(err, "failed to open writer")
}
defer cw.Close()
if _, err := content.CopyReader(cw, r); err != nil {
return "", 0, errors.Wrap(err, "copy failed")
}
st, err := cw.Status()
if err != nil {
return "", 0, errors.Wrap(err, "failed to get state")
}
if err := cw.Commit(ctx, st.Offset, ""); err != nil {
if !errdefs.IsAlreadyExists(err) {
return "", 0, errors.Wrapf(err, "failed commit on ref %q", ref)
}
}
return cw.Digest(), st.Offset, nil
}
// Encrypt or decrypt all the Children of a given descriptor
func cryptChildren(ctx context.Context, cs content.Store, desc ocispec.Descriptor, cc *encconfig.CryptoConfig, lf LayerFilter, cryptoOp cryptoOp, thisPlatform *ocispec.Platform) (ocispec.Descriptor, bool, error) {
children, err := images.Children(ctx, cs, desc)
if err != nil {
if errdefs.IsNotFound(err) {
return desc, false, nil
}
return ocispec.Descriptor{}, false, err
}
var newLayers []ocispec.Descriptor
var config ocispec.Descriptor
modified := false
for _, child := range children {
// we only encrypt child layers and have to update their parents if encryption happened
switch child.MediaType {
case images.MediaTypeDockerSchema2Config, ocispec.MediaTypeImageConfig:
config = child
case images.MediaTypeDockerSchema2LayerGzip, images.MediaTypeDockerSchema2Layer,
ocispec.MediaTypeImageLayerGzip, ocispec.MediaTypeImageLayer:
if cryptoOp == cryptoOpEncrypt && lf(child) {
nl, err := cryptLayer(ctx, cs, child, cc, cryptoOp)
if err != nil {
return ocispec.Descriptor{}, false, err
}
modified = true
newLayers = append(newLayers, nl)
} else {
newLayers = append(newLayers, child)
}
case images.MediaTypeDockerSchema2LayerGzipEnc, images.MediaTypeDockerSchema2LayerEnc:
// this one can be decrypted but also its recipients list changed
if lf(child) {
nl, err := cryptLayer(ctx, cs, child, cc, cryptoOp)
if err != nil || cryptoOp == cryptoOpUnwrapOnly {
return ocispec.Descriptor{}, false, err
}
modified = true
newLayers = append(newLayers, nl)
} else {
newLayers = append(newLayers, child)
}
case images.MediaTypeDockerSchema2LayerForeign, images.MediaTypeDockerSchema2LayerForeignGzip:
// never encrypt/decrypt
newLayers = append(newLayers, child)
default:
return ocispec.Descriptor{}, false, errors.Errorf("bad/unhandled MediaType %s in encryptChildren\n", child.MediaType)
}
}
if modified && len(newLayers) > 0 {
newManifest := ocispec.Manifest{
Versioned: specs.Versioned{
SchemaVersion: 2,
},
Config: config,
Layers: newLayers,
}
mb, err := json.MarshalIndent(newManifest, "", " ")
if err != nil {
return ocispec.Descriptor{}, false, errors.Wrap(err, "failed to marshal image")
}
newDesc := ocispec.Descriptor{
MediaType: ocispec.MediaTypeImageManifest,
Size: int64(len(mb)),
Digest: digest.Canonical.FromBytes(mb),
Platform: desc.Platform,
}
labels := map[string]string{}
labels["containerd.io/gc.ref.content.0"] = newManifest.Config.Digest.String()
for i, ch := range newManifest.Layers {
labels[fmt.Sprintf("containerd.io/gc.ref.content.%d", i+1)] = ch.Digest.String()
}
ref := fmt.Sprintf("manifest-%s", newDesc.Digest.String())
if err := content.WriteBlob(ctx, cs, ref, bytes.NewReader(mb), newDesc, content.WithLabels(labels)); err != nil {
return ocispec.Descriptor{}, false, errors.Wrap(err, "failed to write config")
}
return newDesc, true, nil
}
return desc, modified, nil
}
// cryptManifest encrypts or decrypts the children of a top level manifest
func cryptManifest(ctx context.Context, cs content.Store, desc ocispec.Descriptor, cc *encconfig.CryptoConfig, lf LayerFilter, cryptoOp cryptoOp) (ocispec.Descriptor, bool, error) {
p, err := content.ReadBlob(ctx, cs, desc)
if err != nil {
return ocispec.Descriptor{}, false, err
}
var manifest ocispec.Manifest
if err := json.Unmarshal(p, &manifest); err != nil {
return ocispec.Descriptor{}, false, err
}
platform := platforms.DefaultSpec()
newDesc, modified, err := cryptChildren(ctx, cs, desc, cc, lf, cryptoOp, &platform)
if err != nil || cryptoOp == cryptoOpUnwrapOnly {
return ocispec.Descriptor{}, false, err
}
return newDesc, modified, nil
}
// cryptManifestList encrypts or decrypts the children of a top level manifest list
func cryptManifestList(ctx context.Context, cs content.Store, desc ocispec.Descriptor, cc *encconfig.CryptoConfig, lf LayerFilter, cryptoOp cryptoOp) (ocispec.Descriptor, bool, error) {
// read the index; if any layer is encrypted and any manifests change we will need to rewrite it
b, err := content.ReadBlob(ctx, cs, desc)
if err != nil {
return ocispec.Descriptor{}, false, err
}
var index ocispec.Index
if err := json.Unmarshal(b, &index); err != nil {
return ocispec.Descriptor{}, false, err
}
var newManifests []ocispec.Descriptor
modified := false
for _, manifest := range index.Manifests {
newManifest, m, err := cryptChildren(ctx, cs, manifest, cc, lf, cryptoOp, manifest.Platform)
if err != nil || cryptoOp == cryptoOpUnwrapOnly {
return ocispec.Descriptor{}, false, err
}
if m {
modified = true
}
newManifests = append(newManifests, newManifest)
}
if modified {
// we need to update the index
newIndex := ocispec.Index{
Versioned: index.Versioned,
Manifests: newManifests,
}
mb, err := json.MarshalIndent(newIndex, "", " ")
if err != nil {
return ocispec.Descriptor{}, false, errors.Wrap(err, "failed to marshal index")
}
newDesc := ocispec.Descriptor{
MediaType: ocispec.MediaTypeImageIndex,
Size: int64(len(mb)),
Digest: digest.Canonical.FromBytes(mb),
}
labels := map[string]string{}
for i, m := range newIndex.Manifests {
labels[fmt.Sprintf("containerd.io/gc.ref.content.%d", i)] = m.Digest.String()
}
ref := fmt.Sprintf("index-%s", newDesc.Digest.String())
if err = content.WriteBlob(ctx, cs, ref, bytes.NewReader(mb), newDesc, content.WithLabels(labels)); err != nil {
return ocispec.Descriptor{}, false, errors.Wrap(err, "failed to write index")
}
return newDesc, true, nil
}
return desc, false, nil
}
// cryptImage is the dispatcher to encrypt/decrypt an image; it accepts either an OCI descriptor
// representing a manifest list or a single manifest
func cryptImage(ctx context.Context, cs content.Store, desc ocispec.Descriptor, cc *encconfig.CryptoConfig, lf LayerFilter, cryptoOp cryptoOp) (ocispec.Descriptor, bool, error) {
if cc == nil {
return ocispec.Descriptor{}, false, errors.Wrapf(errdefs.ErrInvalidArgument, "CryptoConfig must not be nil")
}
switch desc.MediaType {
case ocispec.MediaTypeImageIndex, images.MediaTypeDockerSchema2ManifestList:
return cryptManifestList(ctx, cs, desc, cc, lf, cryptoOp)
case ocispec.MediaTypeImageManifest, images.MediaTypeDockerSchema2Manifest:
return cryptManifest(ctx, cs, desc, cc, lf, cryptoOp)
default:
return ocispec.Descriptor{}, false, errors.Errorf("CryptImage: Unhandled media type: %s", desc.MediaType)
}
}
// EncryptImage encrypts an image; it accepts either an OCI descriptor representing a manifest list or a single manifest
func EncryptImage(ctx context.Context, cs content.Store, desc ocispec.Descriptor, cc *encconfig.CryptoConfig, lf LayerFilter) (ocispec.Descriptor, bool, error) {
return cryptImage(ctx, cs, desc, cc, lf, cryptoOpEncrypt)
}
// DecryptImage decrypts an image; it accepts either an OCI descriptor representing a manifest list or a single manifest
func DecryptImage(ctx context.Context, cs content.Store, desc ocispec.Descriptor, cc *encconfig.CryptoConfig, lf LayerFilter) (ocispec.Descriptor, bool, error) {
return cryptImage(ctx, cs, desc, cc, lf, cryptoOpDecrypt)
}
// CheckAuthorization checks whether a user has the right keys to be allowed to access an image (every layer)
// It takes decrypting of the layers only as far as decrypting the asymmetrically encrypted data
// The decryption is only done for the current platform
func CheckAuthorization(ctx context.Context, cs content.Store, desc ocispec.Descriptor, dc *encconfig.DecryptConfig) error {
cc := encconfig.InitDecryption(dc.Parameters)
lf := func(desc ocispec.Descriptor) bool {
return true
}
_, _, err := cryptImage(ctx, cs, desc, &cc, lf, cryptoOpUnwrapOnly)
if err != nil {
return errors.Wrapf(err, "you are not authorized to use this image")
}
return nil
}