mirror of
https://github.com/minio/minio
synced 2024-09-06 08:44:03 +00:00
159 lines
5.2 KiB
Go
159 lines
5.2 KiB
Go
// Copyright (c) 2015-2021 MinIO, Inc.
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//
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// This file is part of MinIO Object Storage stack
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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package crypto
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import (
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"bytes"
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"context"
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"crypto/md5"
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"encoding/base64"
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"net/http"
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xhttp "github.com/minio/minio/internal/http"
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"github.com/minio/minio/internal/logger"
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)
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type ssec struct{}
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var (
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// SSEC represents AWS SSE-C. It provides functionality to handle
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// SSE-C requests.
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SSEC = ssec{}
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_ Type = SSEC
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)
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// String returns the SSE domain as string. For SSE-C the
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// domain is "SSE-C".
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func (ssec) String() string { return "SSE-C" }
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// IsRequested returns true if the HTTP headers contains
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// at least one SSE-C header. SSE-C copy headers are ignored.
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func (ssec) IsRequested(h http.Header) bool {
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if _, ok := h[xhttp.AmzServerSideEncryptionCustomerAlgorithm]; ok {
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return true
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}
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if _, ok := h[xhttp.AmzServerSideEncryptionCustomerKey]; ok {
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return true
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}
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if _, ok := h[xhttp.AmzServerSideEncryptionCustomerKeyMD5]; ok {
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return true
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}
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return false
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}
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// IsEncrypted returns true if the metadata contains an SSE-C
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// entry indicating that the object has been encrypted using
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// SSE-C.
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func (ssec) IsEncrypted(metadata map[string]string) bool {
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if _, ok := metadata[MetaSealedKeySSEC]; ok {
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return true
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}
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return false
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}
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// ParseHTTP parses the SSE-C headers and returns the SSE-C client key
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// on success. SSE-C copy headers are ignored.
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func (ssec) ParseHTTP(h http.Header) (key [32]byte, err error) {
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if h.Get(xhttp.AmzServerSideEncryptionCustomerAlgorithm) != xhttp.AmzEncryptionAES {
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return key, ErrInvalidCustomerAlgorithm
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}
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if h.Get(xhttp.AmzServerSideEncryptionCustomerKey) == "" {
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return key, ErrMissingCustomerKey
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}
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if h.Get(xhttp.AmzServerSideEncryptionCustomerKeyMD5) == "" {
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return key, ErrMissingCustomerKeyMD5
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}
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clientKey, err := base64.StdEncoding.DecodeString(h.Get(xhttp.AmzServerSideEncryptionCustomerKey))
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if err != nil || len(clientKey) != 32 { // The client key must be 256 bits long
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return key, ErrInvalidCustomerKey
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}
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keyMD5, err := base64.StdEncoding.DecodeString(h.Get(xhttp.AmzServerSideEncryptionCustomerKeyMD5))
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if md5Sum := md5.Sum(clientKey); err != nil || !bytes.Equal(md5Sum[:], keyMD5) {
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return key, ErrCustomerKeyMD5Mismatch
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}
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copy(key[:], clientKey)
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return key, nil
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}
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// UnsealObjectKey extracts and decrypts the sealed object key
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// from the metadata using the SSE-C client key of the HTTP headers
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// and returns the decrypted object key.
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func (s3 ssec) UnsealObjectKey(h http.Header, metadata map[string]string, bucket, object string) (key ObjectKey, err error) {
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clientKey, err := s3.ParseHTTP(h)
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if err != nil {
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return
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}
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return unsealObjectKey(clientKey[:], metadata, bucket, object)
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}
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// CreateMetadata encodes the sealed key into the metadata
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// and returns the modified metadata. It allocates a new
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// metadata map if metadata is nil.
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func (ssec) CreateMetadata(metadata map[string]string, sealedKey SealedKey) map[string]string {
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if sealedKey.Algorithm != SealAlgorithm {
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logger.CriticalIf(context.Background(), Errorf("The seal algorithm '%s' is invalid for SSE-C", sealedKey.Algorithm))
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}
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if metadata == nil {
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metadata = make(map[string]string, 3)
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}
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metadata[MetaAlgorithm] = SealAlgorithm
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metadata[MetaIV] = base64.StdEncoding.EncodeToString(sealedKey.IV[:])
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metadata[MetaSealedKeySSEC] = base64.StdEncoding.EncodeToString(sealedKey.Key[:])
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return metadata
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}
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// ParseMetadata extracts all SSE-C related values from the object metadata
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// and checks whether they are well-formed. It returns the sealed object key
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// on success.
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func (ssec) ParseMetadata(metadata map[string]string) (sealedKey SealedKey, err error) {
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// Extract all required values from object metadata
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b64IV, ok := metadata[MetaIV]
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if !ok {
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return sealedKey, errMissingInternalIV
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}
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algorithm, ok := metadata[MetaAlgorithm]
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if !ok {
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return sealedKey, errMissingInternalSealAlgorithm
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}
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b64SealedKey, ok := metadata[MetaSealedKeySSEC]
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if !ok {
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return sealedKey, Errorf("The object metadata is missing the internal sealed key for SSE-C")
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}
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// Check whether all extracted values are well-formed
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iv, err := base64.StdEncoding.DecodeString(b64IV)
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if err != nil || len(iv) != 32 {
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return sealedKey, errInvalidInternalIV
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}
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if algorithm != SealAlgorithm && algorithm != InsecureSealAlgorithm {
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return sealedKey, errInvalidInternalSealAlgorithm
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}
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encryptedKey, err := base64.StdEncoding.DecodeString(b64SealedKey)
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if err != nil || len(encryptedKey) != 64 {
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return sealedKey, Errorf("The internal sealed key for SSE-C is invalid")
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}
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sealedKey.Algorithm = algorithm
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copy(sealedKey.IV[:], iv)
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copy(sealedKey.Key[:], encryptedKey)
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return sealedKey, nil
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}
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