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minio/cmd/crypto/sse.go

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4.0 KiB

// 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"
"errors"
"fmt"
"io"
"net/http"
"github.com/minio/minio/cmd/logger"
"github.com/minio/minio/pkg/ioutil"
"github.com/minio/sio"
)
const (
// SealAlgorithm is the encryption/sealing algorithm used to derive & seal
// the key-encryption-key and to en/decrypt the object data.
SealAlgorithm = "DAREv2-HMAC-SHA256"
// InsecureSealAlgorithm is the legacy encryption/sealing algorithm used
// to derive & seal the key-encryption-key and to en/decrypt the object data.
// This algorithm should not be used for new objects because its key derivation
// is not optimal. See: https://github.com/minio/minio/pull/6121
InsecureSealAlgorithm = "DARE-SHA256"
)
// Type represents an AWS SSE type:
// • SSE-C
// • SSE-S3
// • SSE-KMS
type Type interface {
fmt.Stringer
IsRequested(http.Header) bool
IsEncrypted(map[string]string) bool
}
// IsRequested returns true and the SSE Type if the HTTP headers
// indicate that some form server-side encryption is requested.
//
// If no SSE headers are present then IsRequested returns false
// and no Type.
func IsRequested(h http.Header) (Type, bool) {
switch {
case S3.IsRequested(h):
return S3, true
case S3KMS.IsRequested(h):
return S3KMS, true
case SSEC.IsRequested(h):
return SSEC, true
default:
return nil, false
}
}
// UnsealObjectKey extracts and decrypts the sealed object key
// from the metadata using the SSE-Copy client key of the HTTP headers
// and returns the decrypted object key.
func (sse ssecCopy) UnsealObjectKey(h http.Header, metadata map[string]string, bucket, object string) (key ObjectKey, err error) {
clientKey, err := sse.ParseHTTP(h)
if err != nil {
return
}
return unsealObjectKey(clientKey, metadata, bucket, object)
}
// unsealObjectKey decrypts and returns the sealed object key
// from the metadata using the SSE-C client key.
func unsealObjectKey(clientKey [32]byte, metadata map[string]string, bucket, object string) (key ObjectKey, err error) {
sealedKey, err := SSEC.ParseMetadata(metadata)
if err != nil {
return
}
err = key.Unseal(clientKey, sealedKey, SSEC.String(), bucket, object)
return
}
// EncryptSinglePart encrypts an io.Reader which must be the
// the body of a single-part PUT request.
func EncryptSinglePart(r io.Reader, key ObjectKey) io.Reader {
r, err := sio.EncryptReader(r, sio.Config{MinVersion: sio.Version20, Key: key[:]})
if err != nil {
logger.CriticalIf(context.Background(), errors.New("Unable to encrypt io.Reader using object key"))
}
return r
}
// EncryptMultiPart encrypts an io.Reader which must be the body of
// multi-part PUT request. It derives an unique encryption key from
// the partID and the object key.
func EncryptMultiPart(r io.Reader, partID int, key ObjectKey) io.Reader {
partKey := key.DerivePartKey(uint32(partID))
return EncryptSinglePart(r, ObjectKey(partKey))
}
// DecryptSinglePart decrypts an io.Writer which must an object
// uploaded with the single-part PUT API. The offset and length
// specify the requested range.
func DecryptSinglePart(w io.Writer, offset, length int64, key ObjectKey) io.WriteCloser {
const PayloadSize = 1 << 16 // DARE 2.0
w = ioutil.LimitedWriter(w, offset%PayloadSize, length)
decWriter, err := sio.DecryptWriter(w, sio.Config{Key: key[:]})
if err != nil {
logger.CriticalIf(context.Background(), errors.New("Unable to decrypt io.Writer using object key"))
}
return decWriter
}