minio/cmd/crypto/metadata.go
Andreas Auernhammer 644c2ce326 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.
2018-07-25 13:35:54 -07:00

214 lines
7.1 KiB
Go

// 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
}