crypto: add support for parsing/creating SSE-C/SSE-S3 metadata (#6169)

* crypto: add support for parsing SSE-C/SSE-S3 metadata

This commit adds support for detecting and parsing
SSE-C/SSE-S3 object metadata. With the `IsEncrypted`
functions it is possible to determine whether an object
seems to be encrypted. With the `ParseMetadata` functions
it is possible to validate such metadata and extract the
SSE-C/SSE-S3 related values.

It also fixes some naming issues.

* crypto: add functions for creating SSE object metadata

This commit adds functions for creating SSE-S3 and
SSE-C metadata. It also adds a `CreateMultipartMetadata`
for creating multipart metadata.

For all functions unit tests are included.

cmd/crypto/error.go

@@ -49,6 +49,14 @@ var (
 	ErrCustomerKeyMD5Mismatch = errors.New("The provided SSE-C key MD5 does not match the computed MD5 of the SSE-C key")
 )
 
+var (
+	errMissingInternalIV            = Error{"The object metadata is missing the internal encryption IV"}
+	errMissingInternalSealAlgorithm = Error{"The object metadata is missing the internal seal algorithm"}
+
+	errInvalidInternalIV            = Error{"The internal encryption IV is malformed"}
+	errInvalidInternalSealAlgorithm = Error{"The internal seal algorithm is invalid and not supported"}
+)
+
 var (
 	// errOutOfEntropy indicates that the a source of randomness (PRNG) wasn't able
 	// to produce enough random data. This is fatal error and should cause a panic.

cmd/crypto/header.go

@@ -70,9 +70,9 @@ func (s3) IsRequested(h http.Header) bool {
 	return ok
 }
 
-// Parse parses the SSE-S3 related HTTP headers and checks
+// ParseHTTP parses the SSE-S3 related HTTP headers and checks
 // whether they contain valid values.
-func (s3) Parse(h http.Header) (err error) {
+func (s3) ParseHTTP(h http.Header) (err error) {
 	if h.Get(SSEHeader) != SSEAlgorithmAES256 {
 		err = ErrInvalidEncryptionMethod
 	}
@@ -123,9 +123,9 @@ func (ssecCopy) IsRequested(h http.Header) bool {
 	return false
 }
 
-// Parse parses the SSE-C headers and returns the SSE-C client key
+// ParseHTTP parses the SSE-C headers and returns the SSE-C client key
 // on success. SSE-C copy headers are ignored.
-func (ssec) Parse(h http.Header) (key [32]byte, err error) {
+func (ssec) ParseHTTP(h http.Header) (key [32]byte, err error) {
 	defer h.Del(SSECKey) // remove SSE-C key from headers after parsing
 	if h.Get(SSECAlgorithm) != SSEAlgorithmAES256 {
 		return key, ErrInvalidCustomerAlgorithm
@@ -149,9 +149,9 @@ func (ssec) Parse(h http.Header) (key [32]byte, err error) {
 	return key, nil
 }
 
-// Parse parses the SSE-C copy headers and returns the SSE-C client key
+// ParseHTTP parses the SSE-C copy headers and returns the SSE-C client key
 // on success. Regular SSE-C headers are ignored.
-func (ssecCopy) Parse(h http.Header) (key [32]byte, err error) {
+func (ssecCopy) ParseHTTP(h http.Header) (key [32]byte, err error) {
 	defer h.Del(SSECopyKey) // remove SSE-C copy key of source object from headers after parsing
 	if h.Get(SSECopyAlgorithm) != SSEAlgorithmAES256 {
 		return key, ErrInvalidCustomerAlgorithm

cmd/crypto/header_test.go

@@ -49,7 +49,7 @@ var s3ParseTests = []struct {
 
 func TestS3Parse(t *testing.T) {
 	for i, test := range s3ParseTests {
-		if err := S3.Parse(test.Header); err != test.ExpectedErr {
+		if err := S3.ParseHTTP(test.Header); err != test.ExpectedErr {
 			t.Errorf("Test %d: Wanted '%v' but got '%v'", i, test.ExpectedErr, err)
 		}
 	}
@@ -204,7 +204,7 @@ var ssecParseTests = []struct {
 func TestSSECParse(t *testing.T) {
 	var zeroKey [32]byte
 	for i, test := range ssecParseTests {
-		key, err := SSEC.Parse(test.Header)
+		key, err := SSEC.ParseHTTP(test.Header)
 		if err != test.ExpectedErr {
 			t.Errorf("Test %d: want error '%v' but got '%v'", i, test.ExpectedErr, err)
 		}
@@ -286,7 +286,7 @@ var ssecCopyParseTests = []struct {
 func TestSSECopyParse(t *testing.T) {
 	var zeroKey [32]byte
 	for i, test := range ssecCopyParseTests {
-		key, err := SSECopy.Parse(test.Header)
+		key, err := SSECopy.ParseHTTP(test.Header)
 		if err != test.ExpectedErr {
 			t.Errorf("Test %d: want error '%v' but got '%v'", i, test.ExpectedErr, err)
 		}

cmd/crypto/kms.go

@@ -80,12 +80,12 @@ type KMS interface {
 	// The context is cryptographically bound to the
 	// generated key. The same context must be provided
 	// again to unseal the generated key.
-	GenerateKey(keyID string, context Context) (key, sealedKey []byte, err error)
+	GenerateKey(keyID string, context Context) (key [32]byte, sealedKey []byte, err error)
 
 	// UnsealKey unseals the sealedKey using the master key
 	// referenced by the keyID. The provided context must
 	// match the context used to generate the sealed key.
-	UnsealKey(keyID string, sealedKey []byte, context Context) (key []byte, err error)
+	UnsealKey(keyID string, sealedKey []byte, context Context) (key [32]byte, err error)
 }
 
 type masterKeyKMS struct {
@@ -98,9 +98,8 @@ type masterKeyKMS struct {
 // to the generated keys.
 func NewKMS(key [32]byte) KMS { return &masterKeyKMS{masterKey: key} }
 
-func (kms *masterKeyKMS) GenerateKey(keyID string, ctx Context) (key, sealedKey []byte, err error) {
+func (kms *masterKeyKMS) GenerateKey(keyID string, ctx Context) (key [32]byte, sealedKey []byte, err error) {
-	key = make([]byte, 32)
+	if _, err = io.ReadFull(rand.Reader, key[:]); err != nil {
-	if _, err = io.ReadFull(rand.Reader, key); err != nil {
 		logger.CriticalIf(context.Background(), errOutOfEntropy)
 	}
 
@@ -108,22 +107,22 @@ func (kms *masterKeyKMS) GenerateKey(keyID string, ctx Context) (key, sealedKey
 		buffer     bytes.Buffer
 		derivedKey = kms.deriveKey(keyID, ctx)
 	)
-	if n, err := sio.Encrypt(&buffer, bytes.NewReader(key), sio.Config{Key: derivedKey[:]}); err != nil || n != 64 {
+	if n, err := sio.Encrypt(&buffer, bytes.NewReader(key[:]), sio.Config{Key: derivedKey[:]}); err != nil || n != 64 {
 		logger.CriticalIf(context.Background(), errors.New("KMS: unable to encrypt data key"))
 	}
 	sealedKey = buffer.Bytes()
 	return key, sealedKey, nil
 }
 
-func (kms *masterKeyKMS) UnsealKey(keyID string, sealedKey []byte, ctx Context) (key []byte, err error) {
+func (kms *masterKeyKMS) UnsealKey(keyID string, sealedKey []byte, ctx Context) (key [32]byte, err error) {
 	var (
 		buffer     bytes.Buffer
 		derivedKey = kms.deriveKey(keyID, ctx)
 	)
 	if n, err := sio.Decrypt(&buffer, bytes.NewReader(sealedKey), sio.Config{Key: derivedKey[:]}); err != nil || n != 32 {
-		return nil, err // TODO(aead): upgrade sio to use sio.Error
+		return key, err // TODO(aead): upgrade sio to use sio.Error
 	}
-	key = buffer.Bytes()
+	copy(key[:], buffer.Bytes())
 	return key, nil
 }
 

cmd/crypto/kms_test.go

@@ -53,7 +53,7 @@ func TestMasterKeyKMS(t *testing.T) {
 		if err == nil && test.ShouldFail {
 			t.Errorf("Test %d: KMS unsealed the generated successfully but should have failed", i)
 		}
-		if !test.ShouldFail && !bytes.Equal(key, unsealedKey) {
+		if !test.ShouldFail && !bytes.Equal(key[:], unsealedKey[:]) {
 			t.Errorf("Test %d: The generated and unsealed key differ", i)
 		}
 	}

cmd/crypto/metadata.go

@@ -0,0 +1,213 @@
+// Minio Cloud Storage, (C) 2015, 2016, 2017, 2018 Minio, Inc.
+//
+// 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 crypto
+
+import (
+	"context"
+	"encoding/base64"
+	"fmt"
+
+	"github.com/minio/minio/cmd/logger"
+)
+
+// IsMultiPart returns true if the object metadata indicates
+// that it was uploaded using some form of server-side-encryption
+// and the S3 multipart API.
+func IsMultiPart(metadata map[string]string) bool {
+	if _, ok := metadata[SSEMultipart]; ok {
+		return true
+	}
+	return false
+}
+
+// IsEncrypted returns true if the object metadata indicates
+// that it was uploaded using some form of server-side-encryption.
+//
+// IsEncrypted only checks whether the metadata contains at least
+// one entry indicating SSE-C or SSE-S3.
+func IsEncrypted(metadata map[string]string) bool {
+	if _, ok := metadata[SSEIV]; ok {
+		return true
+	}
+	if _, ok := metadata[SSESealAlgorithm]; ok {
+		return true
+	}
+	if IsMultiPart(metadata) {
+		return true
+	}
+	if S3.IsEncrypted(metadata) {
+		return true
+	}
+	if SSEC.IsEncrypted(metadata) {
+		return true
+	}
+	return false
+}
+
+// IsEncrypted returns true if the object metadata indicates
+// that the object was uploaded using SSE-S3.
+func (s3) IsEncrypted(metadata map[string]string) bool {
+	if _, ok := metadata[S3SealedKey]; ok {
+		return true
+	}
+	if _, ok := metadata[S3KMSKeyID]; ok {
+		return true
+	}
+	if _, ok := metadata[S3KMSSealedKey]; ok {
+		return true
+	}
+	return false
+}
+
+// IsEncrypted returns true if the object metadata indicates
+// that the object was uploaded using SSE-C.
+func (ssec) IsEncrypted(metadata map[string]string) bool {
+	if _, ok := metadata[SSECSealedKey]; ok {
+		return true
+	}
+	return false
+}
+
+// CreateMultipartMetadata adds the multipart flag entry to metadata
+// and returns modifed metadata. It allocates a new metadata map if
+// metadata is nil.
+func CreateMultipartMetadata(metadata map[string]string) map[string]string {
+	if metadata == nil {
+		metadata = map[string]string{}
+	}
+	metadata[SSEMultipart] = ""
+	return metadata
+}
+
+// CreateMetadata encodes the keyID, the sealed kms data key and the sealed key
+// into the metadata and returns the modified metadata. It allocates a new
+// metadata map if metadata is nil.
+func (s3) CreateMetadata(metadata map[string]string, keyID string, kmsKey []byte, sealedKey SealedKey) map[string]string {
+	if sealedKey.Algorithm != SealAlgorithm {
+		logger.CriticalIf(context.Background(), fmt.Errorf("The seal algorithm '%s' is invalid for SSE-S3", sealedKey.Algorithm))
+	}
+
+	if metadata == nil {
+		metadata = map[string]string{}
+	}
+	metadata[S3KMSKeyID] = keyID
+	metadata[SSESealAlgorithm] = sealedKey.Algorithm
+	metadata[SSEIV] = base64.StdEncoding.EncodeToString(sealedKey.IV[:])
+	metadata[S3SealedKey] = base64.StdEncoding.EncodeToString(sealedKey.Key[:])
+	metadata[S3KMSSealedKey] = base64.StdEncoding.EncodeToString(kmsKey)
+	return metadata
+}
+
+// ParseMetadata extracts all SSE-S3 related values from the object metadata
+// and checks whether they are well-formed. It returns the KMS key-ID, the
+// sealed KMS key and the sealed object key on success.
+func (s3) ParseMetadata(metadata map[string]string) (keyID string, kmsKey []byte, sealedKey SealedKey, err error) {
+	// Extract all required values from object metadata
+	b64IV, ok := metadata[SSEIV]
+	if !ok {
+		return keyID, kmsKey, sealedKey, errMissingInternalIV
+	}
+	algorithm, ok := metadata[SSESealAlgorithm]
+	if !ok {
+		return keyID, kmsKey, sealedKey, errMissingInternalSealAlgorithm
+	}
+	b64SealedKey, ok := metadata[S3SealedKey]
+	if !ok {
+		return keyID, kmsKey, sealedKey, Error{"The object metadata is missing the internal sealed key for SSE-S3"}
+	}
+	keyID, ok = metadata[S3KMSKeyID]
+	if !ok {
+		return keyID, kmsKey, sealedKey, Error{"The object metadata is missing the internal KMS key-ID for SSE-S3"}
+	}
+	b64KMSSealedKey, ok := metadata[S3KMSSealedKey]
+	if !ok {
+		return keyID, kmsKey, sealedKey, Error{"The object metadata is missing the internal sealed KMS data key for SSE-S3"}
+	}
+
+	// Check whether all extracted values are well-formed
+	iv, err := base64.StdEncoding.DecodeString(b64IV)
+	if err != nil || len(iv) != 32 {
+		return keyID, kmsKey, sealedKey, errInvalidInternalIV
+	}
+	if algorithm != SealAlgorithm {
+		return keyID, kmsKey, sealedKey, errInvalidInternalSealAlgorithm
+	}
+	encryptedKey, err := base64.StdEncoding.DecodeString(b64SealedKey)
+	if err != nil || len(encryptedKey) != 64 {
+		return keyID, kmsKey, sealedKey, Error{"The internal sealed key for SSE-S3 is invalid"}
+	}
+	kmsKey, err = base64.StdEncoding.DecodeString(b64KMSSealedKey)
+	if err != nil {
+		return keyID, kmsKey, sealedKey, Error{"The internal sealed KMS data key for SSE-S3 is invalid"}
+	}
+
+	sealedKey.Algorithm = algorithm
+	copy(sealedKey.IV[:], iv)
+	copy(sealedKey.Key[:], encryptedKey)
+	return keyID, kmsKey, sealedKey, nil
+}
+
+// CreateMetadata encodes the sealed key into the metadata and returns the modified metadata.
+// It allocates a new metadata map if metadata is nil.
+func (ssec) CreateMetadata(metadata map[string]string, sealedKey SealedKey) map[string]string {
+	if sealedKey.Algorithm != SealAlgorithm {
+		logger.CriticalIf(context.Background(), fmt.Errorf("The seal algorithm '%s' is invalid for SSE-C", sealedKey.Algorithm))
+	}
+
+	if metadata == nil {
+		metadata = map[string]string{}
+	}
+	metadata[SSESealAlgorithm] = SealAlgorithm
+	metadata[SSEIV] = base64.StdEncoding.EncodeToString(sealedKey.IV[:])
+	metadata[SSECSealedKey] = base64.StdEncoding.EncodeToString(sealedKey.Key[:])
+	return metadata
+}
+
+// ParseMetadata extracts all SSE-C related values from the object metadata
+// and checks whether they are well-formed. It returns the sealed object key
+// on success.
+func (ssec) ParseMetadata(metadata map[string]string) (sealedKey SealedKey, err error) {
+	// Extract all required values from object metadata
+	b64IV, ok := metadata[SSEIV]
+	if !ok {
+		return sealedKey, errMissingInternalIV
+	}
+	algorithm, ok := metadata[SSESealAlgorithm]
+	if !ok {
+		return sealedKey, errMissingInternalSealAlgorithm
+	}
+	b64SealedKey, ok := metadata[SSECSealedKey]
+	if !ok {
+		return sealedKey, Error{"The object metadata is missing the internal sealed key for SSE-C"}
+	}
+
+	// Check whether all extracted values are well-formed
+	iv, err := base64.StdEncoding.DecodeString(b64IV)
+	if err != nil || len(iv) != 32 {
+		return sealedKey, errInvalidInternalIV
+	}
+	if algorithm != SealAlgorithm && algorithm != InsecureSealAlgorithm {
+		return sealedKey, errInvalidInternalSealAlgorithm
+	}
+	encryptedKey, err := base64.StdEncoding.DecodeString(b64SealedKey)
+	if err != nil || len(encryptedKey) != 64 {
+		return sealedKey, Error{"The internal sealed key for SSE-C is invalid"}
+	}
+
+	sealedKey.Algorithm = algorithm
+	copy(sealedKey.IV[:], iv)
+	copy(sealedKey.Key[:], encryptedKey)
+	return sealedKey, nil
+}

cmd/crypto/metadata_test.go

@@ -0,0 +1,361 @@
+// Minio Cloud Storage, (C) 2015, 2016, 2017, 2018 Minio, Inc.
+//
+// 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 crypto
+
+import (
+	"bytes"
+	"encoding/base64"
+	"testing"
+
+	"github.com/minio/minio/cmd/logger"
+)
+
+var isMultipartTests = []struct {
+	Metadata  map[string]string
+	Multipart bool
+}{
+	{Multipart: true, Metadata: map[string]string{SSEMultipart: ""}},                           // 0
+	{Multipart: true, Metadata: map[string]string{"X-Minio-Internal-Encrypted-Multipart": ""}}, // 1
+	{Multipart: true, Metadata: map[string]string{SSEMultipart: "some-value"}},                 // 2
+	{Multipart: false, Metadata: map[string]string{"": ""}},                                    // 3
+	{Multipart: false, Metadata: map[string]string{"X-Minio-Internal-EncryptedMultipart": ""}}, // 4
+}
+
+func TestIsMultipart(t *testing.T) {
+	for i, test := range isMultipartTests {
+		if isMultipart := IsMultiPart(test.Metadata); isMultipart != test.Multipart {
+			t.Errorf("Test %d: got '%v' - want '%v'", i, isMultipart, test.Multipart)
+		}
+	}
+}
+
+var isEncryptedTests = []struct {
+	Metadata  map[string]string
+	Encrypted bool
+}{
+	{Encrypted: true, Metadata: map[string]string{SSEMultipart: ""}},                               // 0
+	{Encrypted: true, Metadata: map[string]string{SSEIV: ""}},                                      // 1
+	{Encrypted: true, Metadata: map[string]string{SSESealAlgorithm: ""}},                           // 2
+	{Encrypted: true, Metadata: map[string]string{SSECSealedKey: ""}},                              // 3
+	{Encrypted: true, Metadata: map[string]string{S3SealedKey: ""}},                                // 4
+	{Encrypted: true, Metadata: map[string]string{S3KMSKeyID: ""}},                                 // 5
+	{Encrypted: true, Metadata: map[string]string{S3KMSSealedKey: ""}},                             // 6
+	{Encrypted: false, Metadata: map[string]string{"": ""}},                                        // 7
+	{Encrypted: false, Metadata: map[string]string{"X-Minio-Internal-Server-Side-Encryption": ""}}, // 8
+}
+
+func TestIsEncrypted(t *testing.T) {
+	for i, test := range isEncryptedTests {
+		if isEncrypted := IsEncrypted(test.Metadata); isEncrypted != test.Encrypted {
+			t.Errorf("Test %d: got '%v' - want '%v'", i, isEncrypted, test.Encrypted)
+		}
+	}
+}
+
+var s3IsEncryptedTests = []struct {
+	Metadata  map[string]string
+	Encrypted bool
+}{
+	{Encrypted: false, Metadata: map[string]string{SSEMultipart: ""}},                              // 0
+	{Encrypted: false, Metadata: map[string]string{SSEIV: ""}},                                     // 1
+	{Encrypted: false, Metadata: map[string]string{SSESealAlgorithm: ""}},                          // 2
+	{Encrypted: false, Metadata: map[string]string{SSECSealedKey: ""}},                             // 3
+	{Encrypted: true, Metadata: map[string]string{S3SealedKey: ""}},                                // 4
+	{Encrypted: true, Metadata: map[string]string{S3KMSKeyID: ""}},                                 // 5
+	{Encrypted: true, Metadata: map[string]string{S3KMSSealedKey: ""}},                             // 6
+	{Encrypted: false, Metadata: map[string]string{"": ""}},                                        // 7
+	{Encrypted: false, Metadata: map[string]string{"X-Minio-Internal-Server-Side-Encryption": ""}}, // 8
+}
+
+func TestS3IsEncrypted(t *testing.T) {
+	for i, test := range s3IsEncryptedTests {
+		if isEncrypted := S3.IsEncrypted(test.Metadata); isEncrypted != test.Encrypted {
+			t.Errorf("Test %d: got '%v' - want '%v'", i, isEncrypted, test.Encrypted)
+		}
+	}
+}
+
+var ssecIsEncryptedTests = []struct {
+	Metadata  map[string]string
+	Encrypted bool
+}{
+	{Encrypted: false, Metadata: map[string]string{SSEMultipart: ""}},                              // 0
+	{Encrypted: false, Metadata: map[string]string{SSEIV: ""}},                                     // 1
+	{Encrypted: false, Metadata: map[string]string{SSESealAlgorithm: ""}},                          // 2
+	{Encrypted: true, Metadata: map[string]string{SSECSealedKey: ""}},                              // 3
+	{Encrypted: false, Metadata: map[string]string{S3SealedKey: ""}},                               // 4
+	{Encrypted: false, Metadata: map[string]string{S3KMSKeyID: ""}},                                // 5
+	{Encrypted: false, Metadata: map[string]string{S3KMSSealedKey: ""}},                            // 6
+	{Encrypted: false, Metadata: map[string]string{"": ""}},                                        // 7
+	{Encrypted: false, Metadata: map[string]string{"X-Minio-Internal-Server-Side-Encryption": ""}}, // 8
+}
+
+func TestSSECIsEncrypted(t *testing.T) {
+	for i, test := range ssecIsEncryptedTests {
+		if isEncrypted := SSEC.IsEncrypted(test.Metadata); isEncrypted != test.Encrypted {
+			t.Errorf("Test %d: got '%v' - want '%v'", i, isEncrypted, test.Encrypted)
+		}
+	}
+}
+
+var s3ParseMetadataTests = []struct {
+	Metadata    map[string]string
+	ExpectedErr error
+
+	DataKey   []byte
+	KeyID     string
+	SealedKey SealedKey
+}{
+	{ExpectedErr: errMissingInternalIV, Metadata: map[string]string{}, DataKey: []byte{}, KeyID: "", SealedKey: SealedKey{}}, // 0
+	{
+		ExpectedErr: errMissingInternalSealAlgorithm, Metadata: map[string]string{SSEIV: ""},
+		DataKey: []byte{}, KeyID: "", SealedKey: SealedKey{},
+	}, // 1
+	{
+		ExpectedErr: Error{"The object metadata is missing the internal sealed key for SSE-S3"},
+		Metadata:    map[string]string{SSEIV: "", SSESealAlgorithm: ""}, DataKey: []byte{}, KeyID: "", SealedKey: SealedKey{},
+	}, // 2
+	{
+		ExpectedErr: Error{"The object metadata is missing the internal KMS key-ID for SSE-S3"},
+		Metadata:    map[string]string{SSEIV: "", SSESealAlgorithm: "", S3SealedKey: ""}, DataKey: []byte{}, KeyID: "", SealedKey: SealedKey{},
+	}, // 3
+	{
+		ExpectedErr: Error{"The object metadata is missing the internal sealed KMS data key for SSE-S3"},
+		Metadata:    map[string]string{SSEIV: "", SSESealAlgorithm: "", S3SealedKey: "", S3KMSKeyID: ""},
+		DataKey:     []byte{}, KeyID: "", SealedKey: SealedKey{},
+	}, // 4
+	{
+		ExpectedErr: errInvalidInternalIV,
+		Metadata:    map[string]string{SSEIV: "", SSESealAlgorithm: "", S3SealedKey: "", S3KMSKeyID: "", S3KMSSealedKey: ""},
+		DataKey:     []byte{}, KeyID: "", SealedKey: SealedKey{},
+	}, // 5
+	{
+		ExpectedErr: errInvalidInternalSealAlgorithm,
+		Metadata: map[string]string{
+			SSEIV: base64.StdEncoding.EncodeToString(make([]byte, 32)), SSESealAlgorithm: "", S3SealedKey: "", S3KMSKeyID: "", S3KMSSealedKey: "",
+		},
+		DataKey: []byte{}, KeyID: "", SealedKey: SealedKey{},
+	}, // 6
+	{
+		ExpectedErr: Error{"The internal sealed key for SSE-S3 is invalid"},
+		Metadata: map[string]string{
+			SSEIV: base64.StdEncoding.EncodeToString(make([]byte, 32)), SSESealAlgorithm: SealAlgorithm, S3SealedKey: "",
+			S3KMSKeyID: "", S3KMSSealedKey: "",
+		},
+		DataKey: []byte{}, KeyID: "", SealedKey: SealedKey{},
+	}, // 7
+	{
+		ExpectedErr: Error{"The internal sealed KMS data key for SSE-S3 is invalid"},
+		Metadata: map[string]string{
+			SSEIV: base64.StdEncoding.EncodeToString(make([]byte, 32)), SSESealAlgorithm: SealAlgorithm,
+			S3SealedKey: base64.StdEncoding.EncodeToString(make([]byte, 64)), S3KMSKeyID: "key-1",
+			S3KMSSealedKey: ".MzJieXRlc2xvbmdzZWNyZXRrZXltdXN0cHJvdmlkZWQ=", // invalid base64
+		},
+		DataKey: []byte{}, KeyID: "key-1", SealedKey: SealedKey{},
+	}, // 8
+	{
+		ExpectedErr: nil,
+		Metadata: map[string]string{
+			SSEIV: base64.StdEncoding.EncodeToString(make([]byte, 32)), SSESealAlgorithm: SealAlgorithm,
+			S3SealedKey: base64.StdEncoding.EncodeToString(make([]byte, 64)), S3KMSKeyID: "", S3KMSSealedKey: "",
+		},
+		DataKey: []byte{}, KeyID: "", SealedKey: SealedKey{Algorithm: SealAlgorithm},
+	}, // 9
+	{
+		ExpectedErr: nil,
+		Metadata: map[string]string{
+			SSEIV: base64.StdEncoding.EncodeToString(append([]byte{1}, make([]byte, 31)...)), SSESealAlgorithm: SealAlgorithm,
+			S3SealedKey: base64.StdEncoding.EncodeToString(append([]byte{1}, make([]byte, 63)...)), S3KMSKeyID: "key-1",
+			S3KMSSealedKey: base64.StdEncoding.EncodeToString(make([]byte, 48)),
+		},
+		DataKey: make([]byte, 48), KeyID: "key-1", SealedKey: SealedKey{Algorithm: SealAlgorithm, Key: [64]byte{1}, IV: [32]byte{1}},
+	}, // 10
+}
+
+func TestS3ParseMetadata(t *testing.T) {
+	for i, test := range s3ParseMetadataTests {
+		keyID, dataKey, sealedKey, err := S3.ParseMetadata(test.Metadata)
+		if err != test.ExpectedErr {
+			t.Errorf("Test %d: got error '%v' - want error '%v'", i, err, test.ExpectedErr)
+		}
+		if !bytes.Equal(dataKey, test.DataKey) {
+			t.Errorf("Test %d: got data key '%v' - want data key '%v'", i, dataKey, test.DataKey)
+		}
+		if keyID != test.KeyID {
+			t.Errorf("Test %d: got key-ID '%v' - want key-ID '%v'", i, keyID, test.KeyID)
+		}
+		if sealedKey.Algorithm != test.SealedKey.Algorithm {
+			t.Errorf("Test %d: got sealed key algorithm '%v' - want sealed key algorithm '%v'", i, sealedKey.Algorithm, test.SealedKey.Algorithm)
+		}
+		if !bytes.Equal(sealedKey.Key[:], test.SealedKey.Key[:]) {
+			t.Errorf("Test %d: got sealed key '%v' - want sealed key '%v'", i, sealedKey.Key, test.SealedKey.Key)
+		}
+		if !bytes.Equal(sealedKey.IV[:], test.SealedKey.IV[:]) {
+			t.Errorf("Test %d: got sealed key IV '%v' - want sealed key IV '%v'", i, sealedKey.IV, test.SealedKey.IV)
+		}
+	}
+}
+
+var ssecParseMetadataTests = []struct {
+	Metadata    map[string]string
+	ExpectedErr error
+
+	SealedKey SealedKey
+}{
+	{ExpectedErr: errMissingInternalIV, Metadata: map[string]string{}, SealedKey: SealedKey{}},                     // 0
+	{ExpectedErr: errMissingInternalSealAlgorithm, Metadata: map[string]string{SSEIV: ""}, SealedKey: SealedKey{}}, // 1
+	{
+		ExpectedErr: Error{"The object metadata is missing the internal sealed key for SSE-C"},
+		Metadata:    map[string]string{SSEIV: "", SSESealAlgorithm: ""}, SealedKey: SealedKey{},
+	}, // 2
+	{
+		ExpectedErr: errInvalidInternalIV,
+		Metadata:    map[string]string{SSEIV: "", SSESealAlgorithm: "", SSECSealedKey: ""}, SealedKey: SealedKey{},
+	}, // 3
+	{
+		ExpectedErr: errInvalidInternalSealAlgorithm,
+		Metadata: map[string]string{
+			SSEIV: base64.StdEncoding.EncodeToString(make([]byte, 32)), SSESealAlgorithm: "", SSECSealedKey: "",
+		},
+		SealedKey: SealedKey{},
+	}, // 4
+	{
+		ExpectedErr: Error{"The internal sealed key for SSE-C is invalid"},
+		Metadata: map[string]string{
+			SSEIV: base64.StdEncoding.EncodeToString(make([]byte, 32)), SSESealAlgorithm: SealAlgorithm, SSECSealedKey: "",
+		},
+		SealedKey: SealedKey{},
+	}, // 5
+	{
+		ExpectedErr: nil,
+		Metadata: map[string]string{
+			SSEIV: base64.StdEncoding.EncodeToString(make([]byte, 32)), SSESealAlgorithm: SealAlgorithm,
+			SSECSealedKey: base64.StdEncoding.EncodeToString(make([]byte, 64)),
+		},
+		SealedKey: SealedKey{Algorithm: SealAlgorithm},
+	}, // 6
+	{
+		ExpectedErr: nil,
+		Metadata: map[string]string{
+			SSEIV: base64.StdEncoding.EncodeToString(append([]byte{1}, make([]byte, 31)...)), SSESealAlgorithm: InsecureSealAlgorithm,
+			SSECSealedKey: base64.StdEncoding.EncodeToString(append([]byte{1}, make([]byte, 63)...)),
+		},
+		SealedKey: SealedKey{Algorithm: InsecureSealAlgorithm, Key: [64]byte{1}, IV: [32]byte{1}},
+	}, // 7
+}
+
+func TestCreateMultipartMetadata(t *testing.T) {
+	metadata := CreateMultipartMetadata(nil)
+	if v, ok := metadata[SSEMultipart]; !ok || v != "" {
+		t.Errorf("Metadata is missing the correct value for '%s': got '%s' - want '%s'", SSEMultipart, v, "")
+	}
+}
+
+func TestSSECParseMetadata(t *testing.T) {
+	for i, test := range ssecParseMetadataTests {
+		sealedKey, err := SSEC.ParseMetadata(test.Metadata)
+		if err != test.ExpectedErr {
+			t.Errorf("Test %d: got error '%v' - want error '%v'", i, err, test.ExpectedErr)
+		}
+		if sealedKey.Algorithm != test.SealedKey.Algorithm {
+			t.Errorf("Test %d: got sealed key algorithm '%v' - want sealed key algorithm '%v'", i, sealedKey.Algorithm, test.SealedKey.Algorithm)
+		}
+		if !bytes.Equal(sealedKey.Key[:], test.SealedKey.Key[:]) {
+			t.Errorf("Test %d: got sealed key '%v' - want sealed key '%v'", i, sealedKey.Key, test.SealedKey.Key)
+		}
+		if !bytes.Equal(sealedKey.IV[:], test.SealedKey.IV[:]) {
+			t.Errorf("Test %d: got sealed key IV '%v' - want sealed key IV '%v'", i, sealedKey.IV, test.SealedKey.IV)
+		}
+	}
+}
+
+var s3CreateMetadataTests = []struct {
+	KeyID         string
+	SealedDataKey []byte
+	SealedKey     SealedKey
+}{
+	{KeyID: "", SealedDataKey: make([]byte, 48), SealedKey: SealedKey{Algorithm: SealAlgorithm}},
+	{KeyID: "cafebabe", SealedDataKey: make([]byte, 48), SealedKey: SealedKey{Algorithm: SealAlgorithm}},
+	{KeyID: "deadbeef", SealedDataKey: make([]byte, 32), SealedKey: SealedKey{IV: [32]byte{0xf7}, Key: [64]byte{0xea}, Algorithm: SealAlgorithm}},
+}
+
+func TestS3CreateMetadata(t *testing.T) {
+	defer func(disableLog bool) { logger.Disable = disableLog }(logger.Disable)
+	logger.Disable = true
+	for i, test := range s3CreateMetadataTests {
+		metadata := S3.CreateMetadata(nil, test.KeyID, test.SealedDataKey, test.SealedKey)
+		keyID, kmsKey, sealedKey, err := S3.ParseMetadata(metadata)
+		if err != nil {
+			t.Errorf("Test %d: failed to parse metadata: %v", i, err)
+			continue
+		}
+		if keyID != test.KeyID {
+			t.Errorf("Test %d: Key-ID mismatch: got '%s' - want '%s'", i, keyID, test.KeyID)
+		}
+		if !bytes.Equal(kmsKey, test.SealedDataKey) {
+			t.Errorf("Test %d: sealed KMS data mismatch: got '%v' - want '%v'", i, kmsKey, test.SealedDataKey)
+		}
+		if sealedKey.Algorithm != test.SealedKey.Algorithm {
+			t.Errorf("Test %d: seal algorithm mismatch: got '%s' - want '%s'", i, sealedKey.Algorithm, test.SealedKey.Algorithm)
+		}
+		if !bytes.Equal(sealedKey.IV[:], test.SealedKey.IV[:]) {
+			t.Errorf("Test %d: IV mismatch: got '%v' - want '%v'", i, sealedKey.IV, test.SealedKey.IV)
+		}
+		if !bytes.Equal(sealedKey.Key[:], test.SealedKey.Key[:]) {
+			t.Errorf("Test %d: sealed key mismatch: got '%v' - want '%v'", i, sealedKey.Key, test.SealedKey.Key)
+		}
+	}
+
+	defer func() {
+		if err := recover(); err == nil || err != logger.ErrCritical {
+			t.Errorf("Expected '%s' panic for invalid seal algorithm but got '%s'", logger.ErrCritical, err)
+		}
+	}()
+	_ = S3.CreateMetadata(nil, "", []byte{}, SealedKey{Algorithm: InsecureSealAlgorithm})
+}
+
+var ssecCreateMetadataTests = []SealedKey{
+	{Algorithm: SealAlgorithm},
+	{IV: [32]byte{0xff}, Key: [64]byte{0x7e}, Algorithm: SealAlgorithm},
+}
+
+func TestSSECCreateMetadata(t *testing.T) {
+	defer func(disableLog bool) { logger.Disable = disableLog }(logger.Disable)
+	logger.Disable = true
+	for i, test := range s3CreateMetadataTests {
+		metadata := SSEC.CreateMetadata(nil, test.SealedKey)
+		sealedKey, err := SSEC.ParseMetadata(metadata)
+		if err != nil {
+			t.Errorf("Test %d: failed to parse metadata: %v", i, err)
+			continue
+		}
+		if sealedKey.Algorithm != test.SealedKey.Algorithm {
+			t.Errorf("Test %d: seal algorithm mismatch: got '%s' - want '%s'", i, sealedKey.Algorithm, test.SealedKey.Algorithm)
+		}
+		if !bytes.Equal(sealedKey.IV[:], test.SealedKey.IV[:]) {
+			t.Errorf("Test %d: IV mismatch: got '%v' - want '%v'", i, sealedKey.IV, test.SealedKey.IV)
+		}
+		if !bytes.Equal(sealedKey.Key[:], test.SealedKey.Key[:]) {
+			t.Errorf("Test %d: sealed key mismatch: got '%v' - want '%v'", i, sealedKey.Key, test.SealedKey.Key)
+		}
+	}
+
+	defer func() {
+		if err := recover(); err == nil || err != logger.ErrCritical {
+			t.Errorf("Expected '%s' panic for invalid seal algorithm but got '%s'", logger.ErrCritical, err)
+		}
+	}()
+	_ = SSEC.CreateMetadata(nil, SealedKey{Algorithm: InsecureSealAlgorithm})
+}

cmd/crypto/sse.go

@@ -25,6 +25,11 @@ import (
 )
 
 const (
+	// SSEMultipart is the metadata key indicating that the object
+	// was uploaded using the S3 multipart API and stored using
+	// some from of server-side-encryption.
+	SSEMultipart = "X-Minio-Internal-Encrypted-Multipart"
+
 	// SSEIV is the metadata key referencing the random initialization
 	// vector (IV) used for SSE-S3 and SSE-C key derivation.
 	SSEIV = "X-Minio-Internal-Server-Side-Encryption-Iv"
@@ -33,8 +38,8 @@ const (
 	// used by SSE-C and SSE-S3 to encrypt the object.
 	SSESealAlgorithm = "X-Minio-Internal-Server-Side-Encryption-Seal-Algorithm"
 
-	// SSECSealKey is the metadata key referencing the sealed object-key for SSE-C.
+	// SSECSealedKey is the metadata key referencing the sealed object-key for SSE-C.
-	SSECSealKey = "X-Minio-Internal-Server-Side-Encryption-Sealed-Key"
+	SSECSealedKey = "X-Minio-Internal-Server-Side-Encryption-Sealed-Key"
 
 	// S3SealedKey is the metadata key referencing the sealed object-key for SSE-S3.
 	S3SealedKey = "X-Minio-Internal-Server-Side-Encryption-S3-Sealed-Key"