forked from TrueCloudLab/restic
146 lines
4.9 KiB
Go
146 lines
4.9 KiB
Go
/*
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* Minio Go Library for Amazon S3 Compatible Cloud Storage
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* Copyright 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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*/
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package encrypt
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import (
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"crypto/md5"
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"encoding/base64"
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"errors"
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"net/http"
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"golang.org/x/crypto/argon2"
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)
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const (
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// sseGenericHeader is the AWS SSE header used for SSE-S3 and SSE-KMS.
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sseGenericHeader = "X-Amz-Server-Side-Encryption"
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// sseCustomerAlgorithm is the AWS SSE-C algorithm HTTP header key.
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sseCustomerAlgorithm = sseGenericHeader + "-Customer-Algorithm"
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// sseCustomerKey is the AWS SSE-C encryption key HTTP header key.
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sseCustomerKey = sseGenericHeader + "-Customer-Key"
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// sseCustomerKeyMD5 is the AWS SSE-C encryption key MD5 HTTP header key.
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sseCustomerKeyMD5 = sseGenericHeader + "-Customer-Key-MD5"
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// sseCopyCustomerAlgorithm is the AWS SSE-C algorithm HTTP header key for CopyObject API.
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sseCopyCustomerAlgorithm = "X-Amz-Copy-Source-Server-Side-Encryption-Customer-Algorithm"
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// sseCopyCustomerKey is the AWS SSE-C encryption key HTTP header key for CopyObject API.
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sseCopyCustomerKey = "X-Amz-Copy-Source-Server-Side-Encryption-Customer-Key"
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// sseCopyCustomerKeyMD5 is the AWS SSE-C encryption key MD5 HTTP header key for CopyObject API.
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sseCopyCustomerKeyMD5 = "X-Amz-Copy-Source-Server-Side-Encryption-Customer-Key-MD5"
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)
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// PBKDF creates a SSE-C key from the provided password and salt.
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// PBKDF is a password-based key derivation function
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// which can be used to derive a high-entropy cryptographic
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// key from a low-entropy password and a salt.
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type PBKDF func(password, salt []byte) ServerSide
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// DefaultPBKDF is the default PBKDF. It uses Argon2id with the
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// recommended parameters from the RFC draft (1 pass, 64 MB memory, 4 threads).
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var DefaultPBKDF PBKDF = func(password, salt []byte) ServerSide {
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sse := ssec{}
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copy(sse[:], argon2.IDKey(password, salt, 1, 64*1024, 4, 32))
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return sse
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}
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// Type is the server-side-encryption method. It represents one of
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// the following encryption methods:
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// - SSE-C: server-side-encryption with customer provided keys
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// - KMS: server-side-encryption with managed keys
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// - S3: server-side-encryption using S3 storage encryption
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type Type string
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const (
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// SSEC represents server-side-encryption with customer provided keys
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SSEC Type = "SSE-C"
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// KMS represents server-side-encryption with managed keys
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KMS Type = "KMS"
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// S3 represents server-side-encryption using S3 storage encryption
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S3 Type = "S3"
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)
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// ServerSide is a form of S3 server-side-encryption.
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type ServerSide interface {
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// Type returns the server-side-encryption method.
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Type() Type
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// Marshal adds encryption headers to the provided HTTP headers.
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// It marks an HTTP request as server-side-encryption request
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// and inserts the required data into the headers.
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Marshal(h http.Header)
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}
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// NewSSE returns a server-side-encryption using S3 storage encryption.
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// Using SSE-S3 the server will encrypt the object with server-managed keys.
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func NewSSE() ServerSide { return s3{} }
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// NewSSEC returns a new server-side-encryption using SSE-C and the provided key.
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// The key must be 32 bytes long.
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func NewSSEC(key []byte) (ServerSide, error) {
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if len(key) != 32 {
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return nil, errors.New("encrypt: SSE-C key must be 256 bit long")
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}
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sse := ssec{}
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copy(sse[:], key)
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return sse, nil
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}
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// SSECopy transforms a SSE-C encryption into a SSE-C copy
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// encryption. This is required for SSE-C key rotation or a SSE-C
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// copy where the source and the destination should be encrypted.
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//
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// If the provided sse is no SSE-C encryption SSECopy returns
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// sse unmodified.
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func SSECopy(sse ServerSide) ServerSide {
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if sse == nil || sse.Type() != SSEC {
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return sse
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}
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if sse, ok := sse.(ssec); ok {
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return ssecCopy(sse)
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}
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return sse
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}
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type ssec [32]byte
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func (s ssec) Type() Type { return SSEC }
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func (s ssec) Marshal(h http.Header) {
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keyMD5 := md5.Sum(s[:])
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h.Set(sseCustomerAlgorithm, "AES256")
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h.Set(sseCustomerKey, base64.StdEncoding.EncodeToString(s[:]))
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h.Set(sseCustomerKeyMD5, base64.StdEncoding.EncodeToString(keyMD5[:]))
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}
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type ssecCopy [32]byte
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func (s ssecCopy) Type() Type { return SSEC }
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func (s ssecCopy) Marshal(h http.Header) {
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keyMD5 := md5.Sum(s[:])
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h.Set(sseCopyCustomerAlgorithm, "AES256")
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h.Set(sseCopyCustomerKey, base64.StdEncoding.EncodeToString(s[:]))
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h.Set(sseCopyCustomerKeyMD5, base64.StdEncoding.EncodeToString(keyMD5[:]))
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}
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type s3 struct{}
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func (s s3) Type() Type { return S3 }
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func (s s3) Marshal(h http.Header) { h.Set(sseGenericHeader, "AES256") }
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