minio/cmd/crypto/sse-c.go
Andreas Auernhammer 885c170a64
introduce new package pkg/kms (#12019)
This commit introduces a new package `pkg/kms`.
It contains basic types and functions to interact
with various KMS implementations.

This commit also moves KMS-related code from `cmd/crypto`
to `pkg/kms`. Now, it is possible to implement a KMS-based
config data encryption in the `pkg/config` package.
2021-04-15 08:47:33 -07:00

158 lines
5.1 KiB
Go

/*
* Minio Cloud Storage, (C) 2019-2020 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"
"context"
"crypto/md5"
"encoding/base64"
"net/http"
xhttp "github.com/minio/minio/cmd/http"
"github.com/minio/minio/cmd/logger"
)
type ssec struct{}
var (
// SSEC represents AWS SSE-C. It provides functionality to handle
// SSE-C requests.
SSEC = ssec{}
_ Type = SSEC
)
// String returns the SSE domain as string. For SSE-C the
// domain is "SSE-C".
func (ssec) String() string { return "SSE-C" }
// IsRequested returns true if the HTTP headers contains
// at least one SSE-C header. SSE-C copy headers are ignored.
func (ssec) IsRequested(h http.Header) bool {
if _, ok := h[xhttp.AmzServerSideEncryptionCustomerAlgorithm]; ok {
return true
}
if _, ok := h[xhttp.AmzServerSideEncryptionCustomerKey]; ok {
return true
}
if _, ok := h[xhttp.AmzServerSideEncryptionCustomerKeyMD5]; ok {
return true
}
return false
}
// IsEncrypted returns true if the metadata contains an SSE-C
// entry inidicating that the object has been encrypted using
// SSE-C.
func (ssec) IsEncrypted(metadata map[string]string) bool {
if _, ok := metadata[MetaSealedKeySSEC]; ok {
return true
}
return false
}
// ParseHTTP parses the SSE-C headers and returns the SSE-C client key
// on success. SSE-C copy headers are ignored.
func (ssec) ParseHTTP(h http.Header) (key [32]byte, err error) {
if h.Get(xhttp.AmzServerSideEncryptionCustomerAlgorithm) != xhttp.AmzEncryptionAES {
return key, ErrInvalidCustomerAlgorithm
}
if h.Get(xhttp.AmzServerSideEncryptionCustomerKey) == "" {
return key, ErrMissingCustomerKey
}
if h.Get(xhttp.AmzServerSideEncryptionCustomerKeyMD5) == "" {
return key, ErrMissingCustomerKeyMD5
}
clientKey, err := base64.StdEncoding.DecodeString(h.Get(xhttp.AmzServerSideEncryptionCustomerKey))
if err != nil || len(clientKey) != 32 { // The client key must be 256 bits long
return key, ErrInvalidCustomerKey
}
keyMD5, err := base64.StdEncoding.DecodeString(h.Get(xhttp.AmzServerSideEncryptionCustomerKeyMD5))
if md5Sum := md5.Sum(clientKey); err != nil || !bytes.Equal(md5Sum[:], keyMD5) {
return key, ErrCustomerKeyMD5Mismatch
}
copy(key[:], clientKey)
return key, nil
}
// UnsealObjectKey extracts and decrypts the sealed object key
// from the metadata using the SSE-C client key of the HTTP headers
// and returns the decrypted object key.
func (s3 ssec) UnsealObjectKey(h http.Header, metadata map[string]string, bucket, object string) (key ObjectKey, err error) {
clientKey, err := s3.ParseHTTP(h)
if err != nil {
return
}
return unsealObjectKey(clientKey[:], metadata, bucket, object)
}
// 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(), Errorf("The seal algorithm '%s' is invalid for SSE-C", sealedKey.Algorithm))
}
if metadata == nil {
metadata = make(map[string]string, 3)
}
metadata[MetaAlgorithm] = SealAlgorithm
metadata[MetaIV] = base64.StdEncoding.EncodeToString(sealedKey.IV[:])
metadata[MetaSealedKeySSEC] = 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[MetaIV]
if !ok {
return sealedKey, errMissingInternalIV
}
algorithm, ok := metadata[MetaAlgorithm]
if !ok {
return sealedKey, errMissingInternalSealAlgorithm
}
b64SealedKey, ok := metadata[MetaSealedKeySSEC]
if !ok {
return sealedKey, Errorf("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, Errorf("The internal sealed key for SSE-C is invalid")
}
sealedKey.Algorithm = algorithm
copy(sealedKey.IV[:], iv)
copy(sealedKey.Key[:], encryptedKey)
return sealedKey, nil
}