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minio/cmd/encryption-v1.go

740 lines
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/*
* Minio Cloud Storage, (C) 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 cmd
import (
"context"
"crypto/hmac"
"crypto/rand"
"crypto/subtle"
"encoding/binary"
"errors"
"io"
"net/http"
"path"
"strconv"
"github.com/minio/minio/cmd/crypto"
"github.com/minio/minio/cmd/logger"
"github.com/minio/minio/pkg/ioutil"
sha256 "github.com/minio/sha256-simd"
"github.com/minio/sio"
)
var (
// AWS errors for invalid SSE-C requests.
errInsecureSSERequest = errors.New("SSE-C requests require TLS connections")
errEncryptedObject = errors.New("The object was stored using a form of SSE")
errInvalidSSEParameters = errors.New("The SSE-C key for key-rotation is not correct") // special access denied
errKMSNotConfigured = errors.New("KMS not configured for a server side encrypted object")
// Additional Minio errors for SSE-C requests.
errObjectTampered = errors.New("The requested object was modified and may be compromised")
)
const (
// SSECustomerKeySize is the size of valid client provided encryption keys in bytes.
// Currently AWS supports only AES256. So the SSE-C key size is fixed to 32 bytes.
SSECustomerKeySize = 32
// SSEIVSize is the size of the IV data
SSEIVSize = 32 // 32 bytes
// SSE dare package block size.
sseDAREPackageBlockSize = 64 * 1024 // 64KiB bytes
// SSE dare package meta padding bytes.
sseDAREPackageMetaSize = 32 // 32 bytes
)
const (
// SSESealAlgorithmDareSha256 specifies DARE as authenticated en/decryption scheme and SHA256 as cryptographic
// hash function. The key derivation of DARE-SHA256 is not optimal and does not include the object path.
// It is considered legacy and should not be used anymore.
SSESealAlgorithmDareSha256 = "DARE-SHA256"
// SSESealAlgorithmDareV2HmacSha256 specifies DAREv2 as authenticated en/decryption scheme and SHA256 as cryptographic
// hash function for the HMAC PRF.
SSESealAlgorithmDareV2HmacSha256 = "DAREv2-HMAC-SHA256"
)
// hasServerSideEncryptionHeader returns true if the given HTTP header
// contains server-side-encryption.
func hasServerSideEncryptionHeader(header http.Header) bool {
return crypto.S3.IsRequested(header) || crypto.SSEC.IsRequested(header)
}
// ParseSSECopyCustomerRequest parses the SSE-C header fields of the provided request.
// It returns the client provided key on success.
func ParseSSECopyCustomerRequest(r *http.Request, metadata map[string]string) (key []byte, err error) {
if !globalIsSSL { // minio only supports HTTP or HTTPS requests not both at the same time
// we cannot use r.TLS == nil here because Go's http implementation reflects on
// the net.Conn and sets the TLS field of http.Request only if it's an tls.Conn.
// Minio uses a BufConn (wrapping a tls.Conn) so the type check within the http package
// will always fail -> r.TLS is always nil even for TLS requests.
return nil, errInsecureSSERequest
}
if crypto.S3.IsEncrypted(metadata) && crypto.SSECopy.IsRequested(r.Header) {
return nil, crypto.ErrIncompatibleEncryptionMethod
}
k, err := crypto.SSECopy.ParseHTTP(r.Header)
return k[:], err
}
// ParseSSECustomerRequest parses the SSE-C header fields of the provided request.
// It returns the client provided key on success.
func ParseSSECustomerRequest(r *http.Request) (key []byte, err error) {
return ParseSSECustomerHeader(r.Header)
}
// ParseSSECustomerHeader parses the SSE-C header fields and returns
// the client provided key on success.
func ParseSSECustomerHeader(header http.Header) (key []byte, err error) {
if !globalIsSSL { // minio only supports HTTP or HTTPS requests not both at the same time
// we cannot use r.TLS == nil here because Go's http implementation reflects on
// the net.Conn and sets the TLS field of http.Request only if it's an tls.Conn.
// Minio uses a BufConn (wrapping a tls.Conn) so the type check within the http package
// will always fail -> r.TLS is always nil even for TLS requests.
return nil, errInsecureSSERequest
}
if crypto.S3.IsRequested(header) && crypto.SSEC.IsRequested(header) {
return key, crypto.ErrIncompatibleEncryptionMethod
}
k, err := crypto.SSEC.ParseHTTP(header)
return k[:], err
}
// This function rotates old to new key.
func rotateKey(oldKey []byte, newKey []byte, bucket, object string, metadata map[string]string) error {
delete(metadata, crypto.SSECKey) // make sure we do not save the key by accident
switch {
default:
return errObjectTampered
case crypto.SSEC.IsEncrypted(metadata):
sealedKey, err := crypto.SSEC.ParseMetadata(metadata)
if err != nil {
return err
}
var objectKey crypto.ObjectKey
var extKey [32]byte
copy(extKey[:], oldKey)
if err = objectKey.Unseal(extKey, sealedKey, crypto.SSEC.String(), bucket, object); err != nil {
if subtle.ConstantTimeCompare(oldKey, newKey) == 1 {
return errInvalidSSEParameters // AWS returns special error for equal but invalid keys.
}
return crypto.ErrInvalidCustomerKey // To provide strict AWS S3 compatibility we return: access denied.
}
if subtle.ConstantTimeCompare(oldKey, newKey) == 1 && sealedKey.Algorithm == crypto.SealAlgorithm {
return nil // don't rotate on equal keys if seal algorithm is latest
}
copy(extKey[:], newKey)
sealedKey = objectKey.Seal(extKey, sealedKey.IV, crypto.SSEC.String(), bucket, object)
return nil
}
}
func newEncryptMetadata(key []byte, bucket, object string, metadata map[string]string, sseS3 bool) ([]byte, error) {
delete(metadata, crypto.SSECKey) // make sure we do not save the key by accident
var sealedKey crypto.SealedKey
if sseS3 {
if globalKMS == nil {
return nil, errKMSNotConfigured
}
key, encKey, err := globalKMS.GenerateKey(globalKMSKeyID, crypto.Context{bucket: path.Join(bucket, object)})
if err != nil {
return nil, err
}
objectKey := crypto.GenerateKey(key, rand.Reader)
sealedKey = objectKey.Seal(key, crypto.GenerateIV(rand.Reader), crypto.S3.String(), bucket, object)
crypto.S3.CreateMetadata(metadata, globalKMSKeyID, encKey, sealedKey)
return objectKey[:], nil
}
var extKey [32]byte
copy(extKey[:], key)
objectKey := crypto.GenerateKey(extKey, rand.Reader)
sealedKey = objectKey.Seal(extKey, crypto.GenerateIV(rand.Reader), crypto.SSEC.String(), bucket, object)
crypto.SSEC.CreateMetadata(metadata, sealedKey)
return objectKey[:], nil
}
func newEncryptReader(content io.Reader, key []byte, bucket, object string, metadata map[string]string, sseS3 bool) (io.Reader, error) {
objectEncryptionKey, err := newEncryptMetadata(key, bucket, object, metadata, sseS3)
if err != nil {
return nil, err
}
reader, err := sio.EncryptReader(content, sio.Config{Key: objectEncryptionKey[:], MinVersion: sio.Version20})
if err != nil {
return nil, crypto.ErrInvalidCustomerKey
}
return reader, nil
}
// set new encryption metadata from http request headers for SSE-C and generated key from KMS in the case of
// SSE-S3
func setEncryptionMetadata(r *http.Request, bucket, object string, metadata map[string]string) (err error) {
var (
key []byte
)
if crypto.SSEC.IsRequested(r.Header) {
key, err = ParseSSECustomerRequest(r)
if err != nil {
return
}
}
_, err = newEncryptMetadata(key, bucket, object, metadata, crypto.S3.IsRequested(r.Header))
return
}
// EncryptRequest takes the client provided content and encrypts the data
// with the client provided key. It also marks the object as client-side-encrypted
// and sets the correct headers.
func EncryptRequest(content io.Reader, r *http.Request, bucket, object string, metadata map[string]string) (io.Reader, error) {
var (
key []byte
err error
)
if crypto.S3.IsRequested(r.Header) && crypto.SSEC.IsRequested(r.Header) {
return nil, crypto.ErrIncompatibleEncryptionMethod
}
if crypto.SSEC.IsRequested(r.Header) {
key, err = ParseSSECustomerRequest(r)
if err != nil {
return nil, err
}
}
return newEncryptReader(content, key, bucket, object, metadata, crypto.S3.IsRequested(r.Header))
}
// DecryptCopyRequest decrypts the object with the client provided key. It also removes
// the client-side-encryption metadata from the object and sets the correct headers.
func DecryptCopyRequest(client io.Writer, r *http.Request, bucket, object string, metadata map[string]string) (io.WriteCloser, error) {
var (
key []byte
err error
)
if crypto.SSECopy.IsRequested(r.Header) {
key, err = ParseSSECopyCustomerRequest(r, metadata)
if err != nil {
return nil, err
}
}
delete(metadata, crypto.SSECopyKey) // make sure we do not save the key by accident
return newDecryptWriter(client, key, bucket, object, 0, metadata)
}
func decryptObjectInfo(key []byte, bucket, object string, metadata map[string]string) ([]byte, error) {
switch {
default:
return nil, errObjectTampered
case crypto.S3.IsEncrypted(metadata):
if globalKMS == nil {
return nil, errKMSNotConfigured
}
keyID, kmsKey, sealedKey, err := crypto.S3.ParseMetadata(metadata)
if err != nil {
return nil, err
}
extKey, err := globalKMS.UnsealKey(keyID, kmsKey, crypto.Context{bucket: path.Join(bucket, object)})
if err != nil {
return nil, err
}
var objectKey crypto.ObjectKey
if err = objectKey.Unseal(extKey, sealedKey, crypto.S3.String(), bucket, object); err != nil {
return nil, err
}
return objectKey[:], nil
case crypto.SSEC.IsEncrypted(metadata):
var extKey [32]byte
copy(extKey[:], key)
sealedKey, err := crypto.SSEC.ParseMetadata(metadata)
if err != nil {
return nil, err
}
var objectKey crypto.ObjectKey
if err = objectKey.Unseal(extKey, sealedKey, crypto.SSEC.String(), bucket, object); err != nil {
return nil, err
}
return objectKey[:], nil
}
}
func newDecryptWriter(client io.Writer, key []byte, bucket, object string, seqNumber uint32, metadata map[string]string) (io.WriteCloser, error) {
objectEncryptionKey, err := decryptObjectInfo(key, bucket, object, metadata)
if err != nil {
return nil, err
}
return newDecryptWriterWithObjectKey(client, objectEncryptionKey, seqNumber, metadata)
}
func newDecryptWriterWithObjectKey(client io.Writer, objectEncryptionKey []byte, seqNumber uint32, metadata map[string]string) (io.WriteCloser, error) {
writer, err := sio.DecryptWriter(client, sio.Config{
Key: objectEncryptionKey,
SequenceNumber: seqNumber,
})
if err != nil {
return nil, crypto.ErrInvalidCustomerKey
}
delete(metadata, crypto.SSEIV)
delete(metadata, crypto.SSESealAlgorithm)
delete(metadata, crypto.SSECSealedKey)
delete(metadata, crypto.SSEMultipart)
delete(metadata, crypto.S3SealedKey)
delete(metadata, crypto.S3KMSSealedKey)
delete(metadata, crypto.S3KMSKeyID)
return writer, nil
}
// DecryptRequestWithSequenceNumber decrypts the object with the client provided key. It also removes
// the client-side-encryption metadata from the object and sets the correct headers.
func DecryptRequestWithSequenceNumber(client io.Writer, r *http.Request, bucket, object string, seqNumber uint32, metadata map[string]string) (io.WriteCloser, error) {
if crypto.S3.IsEncrypted(metadata) {
return newDecryptWriter(client, nil, bucket, object, seqNumber, metadata)
}
key, err := ParseSSECustomerRequest(r)
if err != nil {
return nil, err
}
delete(metadata, crypto.SSECKey) // make sure we do not save the key by accident
return newDecryptWriter(client, key, bucket, object, seqNumber, metadata)
}
// DecryptRequest decrypts the object with client provided key for SSE-C and SSE-S3. It also removes
// the encryption metadata from the object and sets the correct headers.
func DecryptRequest(client io.Writer, r *http.Request, bucket, object string, metadata map[string]string) (io.WriteCloser, error) {
return DecryptRequestWithSequenceNumber(client, r, bucket, object, 0, metadata)
}
// DecryptBlocksWriter - decrypts multipart parts, while implementing a io.Writer compatible interface.
type DecryptBlocksWriter struct {
// Original writer where the plain data will be written
writer io.Writer
// Current decrypter for the current encrypted data block
decrypter io.WriteCloser
// Start sequence number
startSeqNum uint32
// Current part index
partIndex int
// Parts information
parts []objectPartInfo
req *http.Request
bucket, object string
metadata map[string]string
partEncRelOffset int64
copySource bool
// Customer Key
customerKeyHeader string
}
func (w *DecryptBlocksWriter) buildDecrypter(partID int) error {
m := make(map[string]string)
for k, v := range w.metadata {
m[k] = v
}
// Initialize the first decrypter, new decrypters will be initialized in Write() operation as needed.
var key []byte
var err error
if w.copySource {
if crypto.SSEC.IsEncrypted(w.metadata) {
w.req.Header.Set(crypto.SSECopyKey, w.customerKeyHeader)
key, err = ParseSSECopyCustomerRequest(w.req, w.metadata)
}
} else {
if crypto.SSEC.IsEncrypted(w.metadata) {
w.req.Header.Set(crypto.SSECKey, w.customerKeyHeader)
key, err = ParseSSECustomerRequest(w.req)
}
}
if err != nil {
return err
}
objectEncryptionKey, err := decryptObjectInfo(key, w.bucket, w.object, m)
if err != nil {
return err
}
var partIDbin [4]byte
binary.LittleEndian.PutUint32(partIDbin[:], uint32(partID)) // marshal part ID
mac := hmac.New(sha256.New, objectEncryptionKey) // derive part encryption key from part ID and object key
mac.Write(partIDbin[:])
partEncryptionKey := mac.Sum(nil)
// make sure we do not save the key by accident
if w.copySource {
delete(m, crypto.SSECopyKey)
} else {
delete(m, crypto.SSECKey)
}
// make sure to provide a NopCloser such that a Close
// on sio.decryptWriter doesn't close the underlying writer's
// close which perhaps can close the stream prematurely.
decrypter, err := newDecryptWriterWithObjectKey(ioutil.NopCloser(w.writer), partEncryptionKey, w.startSeqNum, m)
if err != nil {
return err
}
if w.decrypter != nil {
// Pro-actively close the writer such that any pending buffers
// are flushed already before we allocate a new decrypter.
err = w.decrypter.Close()
if err != nil {
return err
}
}
w.decrypter = decrypter
return nil
}
func (w *DecryptBlocksWriter) Write(p []byte) (int, error) {
var err error
var n1 int
if int64(len(p)) < w.parts[w.partIndex].Size-w.partEncRelOffset {
n1, err = w.decrypter.Write(p)
if err != nil {
return 0, err
}
w.partEncRelOffset += int64(n1)
} else {
n1, err = w.decrypter.Write(p[:w.parts[w.partIndex].Size-w.partEncRelOffset])
if err != nil {
return 0, err
}
// We should now proceed to next part, reset all values appropriately.
w.partEncRelOffset = 0
w.startSeqNum = 0
w.partIndex++
err = w.buildDecrypter(w.partIndex + 1)
if err != nil {
return 0, err
}
n1, err = w.decrypter.Write(p[n1:])
if err != nil {
return 0, err
}
w.partEncRelOffset += int64(n1)
}
return len(p), nil
}
// Close closes the LimitWriter. It behaves like io.Closer.
func (w *DecryptBlocksWriter) Close() error {
if w.decrypter != nil {
err := w.decrypter.Close()
if err != nil {
return err
}
}
if closer, ok := w.writer.(io.Closer); ok {
return closer.Close()
}
return nil
}
// DecryptAllBlocksCopyRequest - setup a struct which can decrypt many concatenated encrypted data
// parts information helps to know the boundaries of each encrypted data block, this function decrypts
// all parts starting from part-1.
func DecryptAllBlocksCopyRequest(client io.Writer, r *http.Request, bucket, object string, objInfo ObjectInfo) (io.WriteCloser, int64, error) {
w, _, size, err := DecryptBlocksRequest(client, r, bucket, object, 0, objInfo.Size, objInfo, true)
return w, size, err
}
// DecryptBlocksRequest - setup a struct which can decrypt many concatenated encrypted data
// parts information helps to know the boundaries of each encrypted data block.
func DecryptBlocksRequest(client io.Writer, r *http.Request, bucket, object string, startOffset, length int64, objInfo ObjectInfo, copySource bool) (io.WriteCloser, int64, int64, error) {
var seqNumber uint32
var encStartOffset, encLength int64
if len(objInfo.Parts) == 0 || !crypto.IsMultiPart(objInfo.UserDefined) {
seqNumber, encStartOffset, encLength = getEncryptedSinglePartOffsetLength(startOffset, length, objInfo)
var writer io.WriteCloser
var err error
if copySource {
writer, err = DecryptCopyRequest(client, r, bucket, object, objInfo.UserDefined)
} else {
writer, err = DecryptRequestWithSequenceNumber(client, r, bucket, object, seqNumber, objInfo.UserDefined)
}
if err != nil {
return nil, 0, 0, err
}
return writer, encStartOffset, encLength, nil
}
seqNumber, encStartOffset, encLength = getEncryptedMultipartsOffsetLength(startOffset, length, objInfo)
var partStartIndex int
var partStartOffset = startOffset
// Skip parts until final offset maps to a particular part offset.
for i, part := range objInfo.Parts {
decryptedSize, err := sio.DecryptedSize(uint64(part.Size))
if err != nil {
return nil, -1, -1, errObjectTampered
}
partStartIndex = i
// Offset is smaller than size we have reached the
// proper part offset, break out we start from
// this part index.
if partStartOffset < int64(decryptedSize) {
break
}
// Continue to look for next part.
partStartOffset -= int64(decryptedSize)
}
startSeqNum := partStartOffset / sseDAREPackageBlockSize
partEncRelOffset := int64(startSeqNum) * (sseDAREPackageBlockSize + sseDAREPackageMetaSize)
w := &DecryptBlocksWriter{
writer: client,
startSeqNum: uint32(startSeqNum),
partEncRelOffset: partEncRelOffset,
parts: objInfo.Parts,
partIndex: partStartIndex,
req: r,
bucket: bucket,
object: object,
customerKeyHeader: r.Header.Get(crypto.SSECKey),
copySource: copySource,
}
w.metadata = map[string]string{}
// Copy encryption metadata for internal use.
for k, v := range objInfo.UserDefined {
w.metadata[k] = v
}
// Purge all the encryption headers.
delete(objInfo.UserDefined, crypto.SSEIV)
delete(objInfo.UserDefined, crypto.SSESealAlgorithm)
delete(objInfo.UserDefined, crypto.SSECSealedKey)
delete(objInfo.UserDefined, crypto.SSEMultipart)
if crypto.S3.IsEncrypted(objInfo.UserDefined) {
delete(objInfo.UserDefined, crypto.S3SealedKey)
delete(objInfo.UserDefined, crypto.S3KMSKeyID)
delete(objInfo.UserDefined, crypto.S3KMSSealedKey)
}
if w.copySource {
w.customerKeyHeader = r.Header.Get(crypto.SSECopyKey)
}
if err := w.buildDecrypter(w.parts[w.partIndex].Number); err != nil {
return nil, 0, 0, err
}
return w, encStartOffset, encLength, nil
}
// getEncryptedMultipartsOffsetLength - fetch sequence number, encrypted start offset and encrypted length.
func getEncryptedMultipartsOffsetLength(offset, length int64, obj ObjectInfo) (uint32, int64, int64) {
// Calculate encrypted offset of a multipart object
computeEncOffset := func(off int64, obj ObjectInfo) (seqNumber uint32, encryptedOffset int64, err error) {
var curPartEndOffset uint64
var prevPartsEncSize int64
for _, p := range obj.Parts {
size, decErr := sio.DecryptedSize(uint64(p.Size))
if decErr != nil {
err = errObjectTampered // assign correct error type
return
}
if off < int64(curPartEndOffset+size) {
seqNumber, encryptedOffset, _ = getEncryptedSinglePartOffsetLength(off-int64(curPartEndOffset), 1, obj)
encryptedOffset += int64(prevPartsEncSize)
break
}
curPartEndOffset += size
prevPartsEncSize += p.Size
}
return
}
// Calculate the encrypted start offset corresponding to the plain offset
seqNumber, encStartOffset, _ := computeEncOffset(offset, obj)
// Calculate also the encrypted end offset corresponding to plain offset + plain length
_, encEndOffset, _ := computeEncOffset(offset+length-1, obj)
// encLength is the diff between encrypted end offset and encrypted start offset + one package size
// to ensure all encrypted data are covered
encLength := encEndOffset - encStartOffset + (64*1024 + 32)
// Calculate total size of all parts
var totalPartsLength int64
for _, p := range obj.Parts {
totalPartsLength += p.Size
}
// Set encLength to maximum possible value if it exceeded total parts size
if encLength+encStartOffset > totalPartsLength {
encLength = totalPartsLength - encStartOffset
}
return seqNumber, encStartOffset, encLength
}
// getEncryptedSinglePartOffsetLength - fetch sequence number, encrypted start offset and encrypted length.
func getEncryptedSinglePartOffsetLength(offset, length int64, objInfo ObjectInfo) (seqNumber uint32, encOffset int64, encLength int64) {
onePkgSize := int64(sseDAREPackageBlockSize + sseDAREPackageMetaSize)
seqNumber = uint32(offset / sseDAREPackageBlockSize)
encOffset = int64(seqNumber) * onePkgSize
// The math to compute the encrypted length is always
// originalLength i.e (offset+length-1) to be divided under
// 64KiB blocks which is the payload size for each encrypted
// block. This is then multiplied by final package size which
// is basically 64KiB + 32. Finally negate the encrypted offset
// to get the final encrypted length on disk.
encLength = ((offset+length)/sseDAREPackageBlockSize)*onePkgSize - encOffset
// Check for the remainder, to figure if we need one extract package to read from.
if (offset+length)%sseDAREPackageBlockSize > 0 {
encLength += onePkgSize
}
if encLength+encOffset > objInfo.EncryptedSize() {
encLength = objInfo.EncryptedSize() - encOffset
}
return seqNumber, encOffset, encLength
}
// DecryptedSize returns the size of the object after decryption in bytes.
// It returns an error if the object is not encrypted or marked as encrypted
// but has an invalid size.
func (o *ObjectInfo) DecryptedSize() (int64, error) {
if !crypto.IsEncrypted(o.UserDefined) {
return 0, errors.New("Cannot compute decrypted size of an unencrypted object")
}
if len(o.Parts) == 0 || !crypto.IsMultiPart(o.UserDefined) {
size, err := sio.DecryptedSize(uint64(o.Size))
if err != nil {
err = errObjectTampered // assign correct error type
}
return int64(size), err
}
var size int64
for _, part := range o.Parts {
partSize, err := sio.DecryptedSize(uint64(part.Size))
if err != nil {
return 0, errObjectTampered
}
size += int64(partSize)
}
return size, nil
}
// EncryptedSize returns the size of the object after encryption.
// An encrypted object is always larger than a plain object
// except for zero size objects.
func (o *ObjectInfo) EncryptedSize() int64 {
size, err := sio.EncryptedSize(uint64(o.Size))
if err != nil {
// This cannot happen since AWS S3 allows parts to be 5GB at most
// sio max. size is 256 TB
reqInfo := (&logger.ReqInfo{}).AppendTags("size", strconv.FormatUint(size, 10))
ctx := logger.SetReqInfo(context.Background(), reqInfo)
logger.CriticalIf(ctx, err)
}
return int64(size)
}
// DecryptCopyObjectInfo tries to decrypt the provided object if it is encrypted.
// It fails if the object is encrypted and the HTTP headers don't contain
// SSE-C headers or the object is not encrypted but SSE-C headers are provided. (AWS behavior)
// DecryptObjectInfo returns 'ErrNone' if the object is not encrypted or the
// decryption succeeded.
//
// DecryptCopyObjectInfo also returns whether the object is encrypted or not.
func DecryptCopyObjectInfo(info *ObjectInfo, headers http.Header) (apiErr APIErrorCode, encrypted bool) {
// Directories are never encrypted.
if info.IsDir {
return ErrNone, false
}
if apiErr, encrypted = ErrNone, crypto.IsEncrypted(info.UserDefined); !encrypted && crypto.SSECopy.IsRequested(headers) {
apiErr = ErrInvalidEncryptionParameters
} else if encrypted {
if (!crypto.SSECopy.IsRequested(headers) && crypto.SSEC.IsEncrypted(info.UserDefined)) ||
(crypto.SSECopy.IsRequested(headers) && crypto.S3.IsEncrypted(info.UserDefined)) {
apiErr = ErrSSEEncryptedObject
return
}
var err error
if info.Size, err = info.DecryptedSize(); err != nil {
apiErr = toAPIErrorCode(err)
}
}
return
}
// DecryptObjectInfo tries to decrypt the provided object if it is encrypted.
// It fails if the object is encrypted and the HTTP headers don't contain
// SSE-C headers or the object is not encrypted but SSE-C headers are provided. (AWS behavior)
// DecryptObjectInfo returns 'ErrNone' if the object is not encrypted or the
// decryption succeeded.
//
// DecryptObjectInfo also returns whether the object is encrypted or not.
func DecryptObjectInfo(info *ObjectInfo, headers http.Header) (apiErr APIErrorCode, encrypted bool) {
// Directories are never encrypted.
if info.IsDir {
return ErrNone, false
}
// disallow X-Amz-Server-Side-Encryption header on HEAD and GET
if crypto.S3.IsRequested(headers) {
apiErr = ErrInvalidEncryptionParameters
return
}
if apiErr, encrypted = ErrNone, crypto.IsEncrypted(info.UserDefined); !encrypted && crypto.SSEC.IsRequested(headers) {
apiErr = ErrInvalidEncryptionParameters
} else if encrypted {
if (crypto.SSEC.IsEncrypted(info.UserDefined) && !crypto.SSEC.IsRequested(headers)) ||
(crypto.S3.IsEncrypted(info.UserDefined) && crypto.SSEC.IsRequested(headers)) {
apiErr = ErrSSEEncryptedObject
return
}
var err error
if info.Size, err = info.DecryptedSize(); err != nil {
apiErr = toAPIErrorCode(err)
}
}
return
}