221 lines
6.6 KiB
Go
221 lines
6.6 KiB
Go
// Minio Cloud Storage, (C) 2015, 2016, 2017, 2018 Minio, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package crypto
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import (
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"bytes"
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"crypto/md5"
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"encoding/base64"
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"net/http"
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"strings"
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)
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// SSEHeader is the general AWS SSE HTTP header key.
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const SSEHeader = "X-Amz-Server-Side-Encryption"
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const (
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// SSEKmsID is the HTTP header key referencing the SSE-KMS
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// key ID.
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SSEKmsID = SSEHeader + "-Aws-Kms-Key-Id"
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// SSEKmsContext is the HTTP header key referencing the
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// SSE-KMS encryption context.
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SSEKmsContext = SSEHeader + "-Context"
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)
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const (
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// SSECAlgorithm is the HTTP header key referencing
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// the SSE-C algorithm.
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SSECAlgorithm = SSEHeader + "-Customer-Algorithm"
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// SSECKey is the HTTP header key referencing the
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// SSE-C client-provided key..
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SSECKey = SSEHeader + "-Customer-Key"
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// SSECKeyMD5 is the HTTP header key referencing
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// the MD5 sum of the client-provided key.
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SSECKeyMD5 = SSEHeader + "-Customer-Key-Md5"
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)
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const (
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// SSECopyAlgorithm is the HTTP header key referencing
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// the SSE-C algorithm for SSE-C copy requests.
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SSECopyAlgorithm = "X-Amz-Copy-Source-Server-Side-Encryption-Customer-Algorithm"
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// SSECopyKey is the HTTP header key referencing the SSE-C
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// client-provided key for SSE-C copy requests.
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SSECopyKey = "X-Amz-Copy-Source-Server-Side-Encryption-Customer-Key"
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// SSECopyKeyMD5 is the HTTP header key referencing the
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// MD5 sum of the client key for SSE-C copy requests.
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SSECopyKeyMD5 = "X-Amz-Copy-Source-Server-Side-Encryption-Customer-Key-Md5"
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)
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const (
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// SSEAlgorithmAES256 is the only supported value for the SSE-S3 or SSE-C algorithm header.
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// For SSE-S3 see: https://docs.aws.amazon.com/AmazonS3/latest/dev/SSEUsingRESTAPI.html
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// For SSE-C see: https://docs.aws.amazon.com/AmazonS3/latest/dev/ServerSideEncryptionCustomerKeys.html
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SSEAlgorithmAES256 = "AES256"
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// SSEAlgorithmKMS is the value of 'X-Amz-Server-Side-Encryption' for SSE-KMS.
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// See: https://docs.aws.amazon.com/AmazonS3/latest/dev/UsingKMSEncryption.html
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SSEAlgorithmKMS = "aws:kms"
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)
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// RemoveSensitiveHeaders removes confidential encryption
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// information - e.g. the SSE-C key - from the HTTP headers.
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// It has the same semantics as RemoveSensitiveEntires.
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func RemoveSensitiveHeaders(h http.Header) {
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h.Del(SSECKey)
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h.Del(SSECopyKey)
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}
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// S3 represents AWS SSE-S3. It provides functionality to handle
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// SSE-S3 requests.
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var S3 = s3{}
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type s3 struct{}
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// IsRequested returns true if the HTTP headers indicates that
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// the S3 client requests SSE-S3.
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func (s3) IsRequested(h http.Header) bool {
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_, ok := h[SSEHeader]
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return ok && strings.ToLower(h.Get(SSEHeader)) != SSEAlgorithmKMS // Return only true if the SSE header is specified and does not contain the SSE-KMS value
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}
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// ParseHTTP parses the SSE-S3 related HTTP headers and checks
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// whether they contain valid values.
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func (s3) ParseHTTP(h http.Header) (err error) {
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if h.Get(SSEHeader) != SSEAlgorithmAES256 {
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err = ErrInvalidEncryptionMethod
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}
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return
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}
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// S3KMS represents AWS SSE-KMS. It provides functionality to
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// handle SSE-KMS requests.
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var S3KMS = s3KMS{}
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type s3KMS struct{}
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// IsRequested returns true if the HTTP headers indicates that
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// the S3 client requests SSE-KMS.
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func (s3KMS) IsRequested(h http.Header) bool {
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if _, ok := h[SSEKmsID]; ok {
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return true
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}
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if _, ok := h[SSEKmsContext]; ok {
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return true
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}
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if _, ok := h[SSEHeader]; ok {
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return strings.ToUpper(h.Get(SSEHeader)) != SSEAlgorithmAES256 // Return only true if the SSE header is specified and does not contain the SSE-S3 value
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}
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return false
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}
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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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// SSECopy represents AWS SSE-C for copy requests. It provides
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// functionality to handle SSE-C copy requests.
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SSECopy = ssecCopy{}
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)
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type ssec struct{}
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type ssecCopy struct{}
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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[SSECAlgorithm]; ok {
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return true
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}
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if _, ok := h[SSECKey]; ok {
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return true
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}
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if _, ok := h[SSECKeyMD5]; 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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// IsRequested returns true if the HTTP headers contains
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// at least one SSE-C copy header. Regular SSE-C headers
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// are ignored.
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func (ssecCopy) IsRequested(h http.Header) bool {
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if _, ok := h[SSECopyAlgorithm]; ok {
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return true
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}
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if _, ok := h[SSECopyKey]; ok {
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return true
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}
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if _, ok := h[SSECopyKeyMD5]; 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(SSECAlgorithm) != SSEAlgorithmAES256 {
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return key, ErrInvalidCustomerAlgorithm
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}
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if h.Get(SSECKey) == "" {
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return key, ErrMissingCustomerKey
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}
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if h.Get(SSECKeyMD5) == "" {
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return key, ErrMissingCustomerKeyMD5
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}
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clientKey, err := base64.StdEncoding.DecodeString(h.Get(SSECKey))
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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(SSECKeyMD5))
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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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// ParseHTTP parses the SSE-C copy headers and returns the SSE-C client key
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// on success. Regular SSE-C headers are ignored.
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func (ssecCopy) ParseHTTP(h http.Header) (key [32]byte, err error) {
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if h.Get(SSECopyAlgorithm) != SSEAlgorithmAES256 {
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return key, ErrInvalidCustomerAlgorithm
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}
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if h.Get(SSECopyKey) == "" {
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return key, ErrMissingCustomerKey
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}
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if h.Get(SSECopyKeyMD5) == "" {
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return key, ErrMissingCustomerKeyMD5
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}
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clientKey, err := base64.StdEncoding.DecodeString(h.Get(SSECopyKey))
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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(SSECopyKeyMD5))
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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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