This commit replaces the en/decrypted size computation with functions from the `sio` package. Fixes #5657
815 lines
30 KiB
Go
815 lines
30 KiB
Go
/*
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* Minio Cloud Storage, (C) 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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*/
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package cmd
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import (
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"bytes"
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"crypto/hmac"
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"crypto/md5"
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"crypto/rand"
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"crypto/subtle"
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"encoding/base64"
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"encoding/binary"
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"errors"
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"io"
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"net/http"
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"github.com/minio/minio/pkg/ioutil"
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sha256 "github.com/minio/sha256-simd"
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"github.com/minio/sio"
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)
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var (
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// AWS errors for invalid SSE-C requests.
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errInsecureSSERequest = errors.New("Requests specifying Server Side Encryption with Customer provided keys must be made over a secure connection")
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errEncryptedObject = errors.New("The object was stored using a form of Server Side Encryption. The correct parameters must be provided to retrieve the object")
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errInvalidSSEAlgorithm = errors.New("Requests specifying Server Side Encryption with Customer provided keys must provide a valid encryption algorithm")
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errMissingSSEKey = errors.New("Requests specifying Server Side Encryption with Customer provided keys must provide an appropriate secret key")
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errInvalidSSEKey = errors.New("The secret key was invalid for the specified algorithm")
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errMissingSSEKeyMD5 = errors.New("Requests specifying Server Side Encryption with Customer provided keys must provide the client calculated MD5 of the secret key")
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errSSEKeyMD5Mismatch = errors.New("The calculated MD5 hash of the key did not match the hash that was provided")
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errSSEKeyMismatch = errors.New("The client provided key does not match the key provided when the object was encrypted") // this msg is not shown to the client
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// Additional Minio errors for SSE-C requests.
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errObjectTampered = errors.New("The requested object was modified and may be compromised")
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)
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const (
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// SSECustomerAlgorithm is the AWS SSE-C algorithm HTTP header key.
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SSECustomerAlgorithm = "X-Amz-Server-Side-Encryption-Customer-Algorithm"
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// SSECustomerKey is the AWS SSE-C encryption key HTTP header key.
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SSECustomerKey = "X-Amz-Server-Side-Encryption-Customer-Key"
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// SSECustomerKeyMD5 is the AWS SSE-C encryption key MD5 HTTP header key.
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SSECustomerKeyMD5 = "X-Amz-Server-Side-Encryption-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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const (
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// SSECustomerKeySize is the size of valid client provided encryption keys in bytes.
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// Currently AWS supports only AES256. So the SSE-C key size is fixed to 32 bytes.
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SSECustomerKeySize = 32
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// SSEIVSize is the size of the IV data
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SSEIVSize = 32 // 32 bytes
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// SSECustomerAlgorithmAES256 the only valid S3 SSE-C encryption algorithm identifier.
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SSECustomerAlgorithmAES256 = "AES256"
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// SSE dare package block size.
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sseDAREPackageBlockSize = 64 * 1024 // 64KiB bytes
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// SSE dare package meta padding bytes.
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sseDAREPackageMetaSize = 32 // 32 bytes
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)
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// SSE-C key derivation, key verification and key update:
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// H: Hash function [32 = |H(m)|]
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// AE: authenticated encryption scheme, AD: authenticated decryption scheme [m = AD(k, AE(k, m))]
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//
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// Key derivation:
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// Input:
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// key := 32 bytes # client provided key
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// Re, Rm := 32 bytes, 32 bytes # uniformly random
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//
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// Seal:
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// k := H(key || Re) # object encryption key
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// r := H(Rm) # save as object metadata [ServerSideEncryptionIV]
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// KeK := H(key || r) # key encryption key
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// K := AE(KeK, k) # save as object metadata [ServerSideEncryptionSealedKey]
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// ------------------------------------------------------------------------------------------------
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// Key verification:
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// Input:
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// key := 32 bytes # client provided key
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// r := 32 bytes # object metadata [ServerSideEncryptionIV]
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// K := 32 bytes # object metadata [ServerSideEncryptionSealedKey]
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//
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// Open:
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// KeK := H(key || r) # key encryption key
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// k := AD(Kek, K) # object encryption key
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// -------------------------------------------------------------------------------------------------
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// Key update:
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// Input:
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// key := 32 bytes # old client provided key
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// key' := 32 bytes # new client provided key
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// Rm := 32 bytes # uniformly random
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// r := 32 bytes # object metadata [ServerSideEncryptionIV]
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// K := 32 bytes # object metadata [ServerSideEncryptionSealedKey]
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//
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// Update:
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// 1. open:
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// KeK := H(key || r) # key encryption key
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// k := AD(Kek, K) # object encryption key
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// 2. seal:
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// r' := H(Rm) # save as object metadata [ServerSideEncryptionIV]
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// KeK' := H(key' || r') # new key encryption key
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// K' := AE(KeK', k) # save as object metadata [ServerSideEncryptionSealedKey]
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const (
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// ServerSideEncryptionIV is a 32 byte randomly generated IV used to derive an
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// unique key encryption key from the client provided key. The combination of this value
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// and the client-provided key MUST be unique.
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ServerSideEncryptionIV = ReservedMetadataPrefix + "Server-Side-Encryption-Iv"
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// ServerSideEncryptionSealAlgorithm identifies a combination of a cryptographic hash function and
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// an authenticated en/decryption scheme to seal the object encryption key.
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ServerSideEncryptionSealAlgorithm = ReservedMetadataPrefix + "Server-Side-Encryption-Seal-Algorithm"
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// ServerSideEncryptionSealedKey is the sealed object encryption key. The sealed key can be decrypted
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// by the key encryption key derived from the client provided key and the server-side-encryption IV.
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ServerSideEncryptionSealedKey = ReservedMetadataPrefix + "Server-Side-Encryption-Sealed-Key"
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)
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// SSESealAlgorithmDareSha256 specifies DARE as authenticated en/decryption scheme and SHA256 as cryptographic
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// hash function.
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const SSESealAlgorithmDareSha256 = "DARE-SHA256"
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// hasSSECustomerHeader returns true if the given HTTP header
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// contains server-side-encryption with customer provided key fields.
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func hasSSECustomerHeader(header http.Header) bool {
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return header.Get(SSECustomerAlgorithm) != "" || header.Get(SSECustomerKey) != "" || header.Get(SSECustomerKeyMD5) != ""
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}
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// hasSSECopyCustomerHeader returns true if the given HTTP header
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// contains copy source server-side-encryption with customer provided key fields.
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func hasSSECopyCustomerHeader(header http.Header) bool {
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return header.Get(SSECopyCustomerAlgorithm) != "" || header.Get(SSECopyCustomerKey) != "" || header.Get(SSECopyCustomerKeyMD5) != ""
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}
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// ParseSSECopyCustomerRequest parses the SSE-C header fields of the provided request.
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// It returns the client provided key on success.
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func ParseSSECopyCustomerRequest(r *http.Request) (key []byte, err error) {
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if !globalIsSSL { // minio only supports HTTP or HTTPS requests not both at the same time
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// we cannot use r.TLS == nil here because Go's http implementation reflects on
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// the net.Conn and sets the TLS field of http.Request only if it's an tls.Conn.
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// Minio uses a BufConn (wrapping a tls.Conn) so the type check within the http package
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// will always fail -> r.TLS is always nil even for TLS requests.
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return nil, errInsecureSSERequest
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}
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header := r.Header
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if algorithm := header.Get(SSECopyCustomerAlgorithm); algorithm != SSECustomerAlgorithmAES256 {
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return nil, errInvalidSSEAlgorithm
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}
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if header.Get(SSECopyCustomerKey) == "" {
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return nil, errMissingSSEKey
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}
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if header.Get(SSECopyCustomerKeyMD5) == "" {
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return nil, errMissingSSEKeyMD5
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}
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key, err = base64.StdEncoding.DecodeString(header.Get(SSECopyCustomerKey))
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if err != nil {
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return nil, errInvalidSSEKey
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}
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if len(key) != SSECustomerKeySize {
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return nil, errInvalidSSEKey
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}
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// Make sure we purged the keys from http headers by now.
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header.Del(SSECopyCustomerKey)
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keyMD5, err := base64.StdEncoding.DecodeString(header.Get(SSECopyCustomerKeyMD5))
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if err != nil {
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return nil, errSSEKeyMD5Mismatch
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}
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if md5Sum := md5.Sum(key); !bytes.Equal(md5Sum[:], keyMD5) {
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return nil, errSSEKeyMD5Mismatch
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}
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return key, nil
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}
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// ParseSSECustomerRequest parses the SSE-C header fields of the provided request.
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// It returns the client provided key on success.
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func ParseSSECustomerRequest(r *http.Request) (key []byte, err error) {
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return ParseSSECustomerHeader(r.Header)
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}
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// ParseSSECustomerHeader parses the SSE-C header fields and returns
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// the client provided key on success.
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func ParseSSECustomerHeader(header http.Header) (key []byte, err error) {
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if !globalIsSSL { // minio only supports HTTP or HTTPS requests not both at the same time
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// we cannot use r.TLS == nil here because Go's http implementation reflects on
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// the net.Conn and sets the TLS field of http.Request only if it's an tls.Conn.
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// Minio uses a BufConn (wrapping a tls.Conn) so the type check within the http package
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// will always fail -> r.TLS is always nil even for TLS requests.
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return nil, errInsecureSSERequest
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}
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if algorithm := header.Get(SSECustomerAlgorithm); algorithm != SSECustomerAlgorithmAES256 {
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return nil, errInvalidSSEAlgorithm
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}
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if header.Get(SSECustomerKey) == "" {
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return nil, errMissingSSEKey
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}
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if header.Get(SSECustomerKeyMD5) == "" {
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return nil, errMissingSSEKeyMD5
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}
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key, err = base64.StdEncoding.DecodeString(header.Get(SSECustomerKey))
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if err != nil {
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return nil, errInvalidSSEKey
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}
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if len(key) != SSECustomerKeySize {
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return nil, errInvalidSSEKey
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}
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// Make sure we purged the keys from http headers by now.
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header.Del(SSECustomerKey)
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keyMD5, err := base64.StdEncoding.DecodeString(header.Get(SSECustomerKeyMD5))
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if err != nil {
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return nil, errSSEKeyMD5Mismatch
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}
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if md5Sum := md5.Sum(key); !bytes.Equal(md5Sum[:], keyMD5) {
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return nil, errSSEKeyMD5Mismatch
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}
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return key, nil
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}
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// This function rotates old to new key.
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func rotateKey(oldKey []byte, newKey []byte, metadata map[string]string) error {
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if subtle.ConstantTimeCompare(oldKey, newKey) == 1 {
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return nil
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}
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delete(metadata, SSECustomerKey) // make sure we do not save the key by accident
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if metadata[ServerSideEncryptionSealAlgorithm] != SSESealAlgorithmDareSha256 { // currently DARE-SHA256 is the only option
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return errObjectTampered
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}
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iv, err := base64.StdEncoding.DecodeString(metadata[ServerSideEncryptionIV])
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if err != nil || len(iv) != SSEIVSize {
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return errObjectTampered
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}
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sealedKey, err := base64.StdEncoding.DecodeString(metadata[ServerSideEncryptionSealedKey])
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if err != nil || len(sealedKey) != 64 {
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return errObjectTampered
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}
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sha := sha256.New() // derive key encryption key
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sha.Write(oldKey)
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sha.Write(iv)
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keyEncryptionKey := sha.Sum(nil)
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objectEncryptionKey := bytes.NewBuffer(nil) // decrypt object encryption key
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n, err := sio.Decrypt(objectEncryptionKey, bytes.NewReader(sealedKey), sio.Config{
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Key: keyEncryptionKey,
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})
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if n != 32 || err != nil {
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// Either the provided key does not match or the object was tampered.
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// To provide strict AWS S3 compatibility we return: access denied.
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return errSSEKeyMismatch
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}
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nonce := make([]byte, 32) // generate random values for key derivation
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if _, err = io.ReadFull(rand.Reader, nonce); err != nil {
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return err
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}
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niv := sha256.Sum256(nonce[:]) // derive key encryption key
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sha = sha256.New()
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sha.Write(newKey)
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sha.Write(niv[:])
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keyEncryptionKey = sha.Sum(nil)
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sealedKeyW := bytes.NewBuffer(nil) // sealedKey := 16 byte header + 32 byte payload + 16 byte tag
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n, err = sio.Encrypt(sealedKeyW, bytes.NewReader(objectEncryptionKey.Bytes()), sio.Config{
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Key: keyEncryptionKey,
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})
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if n != 64 || err != nil {
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return errors.New("failed to seal object encryption key") // if this happens there's a bug in the code (may panic ?)
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}
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metadata[ServerSideEncryptionIV] = base64.StdEncoding.EncodeToString(niv[:])
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metadata[ServerSideEncryptionSealAlgorithm] = SSESealAlgorithmDareSha256
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metadata[ServerSideEncryptionSealedKey] = base64.StdEncoding.EncodeToString(sealedKeyW.Bytes())
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return nil
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}
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func newEncryptMetadata(key []byte, metadata map[string]string) ([]byte, error) {
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delete(metadata, SSECustomerKey) // make sure we do not save the key by accident
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// security notice:
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// - If the first 32 bytes of the random value are ever repeated under the same client-provided
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// key the encrypted object will not be tamper-proof. [ P(coll) ~= 1 / 2^(256 / 2)]
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// - If the last 32 bytes of the random value are ever repeated under the same client-provided
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// key an adversary may be able to extract the object encryption key. This depends on the
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// authenticated en/decryption scheme. The DARE format will generate an 8 byte nonce which must
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// be repeated in addition to reveal the object encryption key.
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// [ P(coll) ~= 1 / 2^((256 + 64) / 2) ]
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nonce := make([]byte, 32+SSEIVSize) // generate random values for key derivation
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if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
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return nil, err
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}
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sha := sha256.New() // derive object encryption key
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sha.Write(key)
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sha.Write(nonce[:32])
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objectEncryptionKey := sha.Sum(nil)
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iv := sha256.Sum256(nonce[32:]) // derive key encryption key
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sha = sha256.New()
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sha.Write(key)
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sha.Write(iv[:])
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keyEncryptionKey := sha.Sum(nil)
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sealedKey := bytes.NewBuffer(nil) // sealedKey := 16 byte header + 32 byte payload + 16 byte tag
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n, err := sio.Encrypt(sealedKey, bytes.NewReader(objectEncryptionKey), sio.Config{
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Key: keyEncryptionKey,
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})
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if n != 64 || err != nil {
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return nil, errors.New("failed to seal object encryption key") // if this happens there's a bug in the code (may panic ?)
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}
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metadata[ServerSideEncryptionIV] = base64.StdEncoding.EncodeToString(iv[:])
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metadata[ServerSideEncryptionSealAlgorithm] = SSESealAlgorithmDareSha256
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metadata[ServerSideEncryptionSealedKey] = base64.StdEncoding.EncodeToString(sealedKey.Bytes())
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return objectEncryptionKey, nil
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}
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func newEncryptReader(content io.Reader, key []byte, metadata map[string]string) (io.Reader, error) {
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objectEncryptionKey, err := newEncryptMetadata(key, metadata)
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if err != nil {
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return nil, err
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}
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reader, err := sio.EncryptReader(content, sio.Config{Key: objectEncryptionKey})
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if err != nil {
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return nil, errInvalidSSEKey
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}
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return reader, nil
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}
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// EncryptRequest takes the client provided content and encrypts the data
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// with the client provided key. It also marks the object as client-side-encrypted
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// and sets the correct headers.
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func EncryptRequest(content io.Reader, r *http.Request, metadata map[string]string) (io.Reader, error) {
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key, err := ParseSSECustomerRequest(r)
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if err != nil {
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return nil, err
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}
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return newEncryptReader(content, key, metadata)
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}
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// DecryptCopyRequest decrypts the object with the client provided key. It also removes
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// the client-side-encryption metadata from the object and sets the correct headers.
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func DecryptCopyRequest(client io.Writer, r *http.Request, metadata map[string]string) (io.WriteCloser, error) {
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key, err := ParseSSECopyCustomerRequest(r)
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if err != nil {
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return nil, err
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}
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delete(metadata, SSECopyCustomerKey) // make sure we do not save the key by accident
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return newDecryptWriter(client, key, 0, metadata)
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}
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func decryptObjectInfo(key []byte, metadata map[string]string) ([]byte, error) {
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if metadata[ServerSideEncryptionSealAlgorithm] != SSESealAlgorithmDareSha256 { // currently DARE-SHA256 is the only option
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return nil, errObjectTampered
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}
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iv, err := base64.StdEncoding.DecodeString(metadata[ServerSideEncryptionIV])
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if err != nil || len(iv) != SSEIVSize {
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return nil, errObjectTampered
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}
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sealedKey, err := base64.StdEncoding.DecodeString(metadata[ServerSideEncryptionSealedKey])
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if err != nil || len(sealedKey) != 64 {
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return nil, errObjectTampered
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}
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sha := sha256.New() // derive key encryption key
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sha.Write(key)
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sha.Write(iv)
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keyEncryptionKey := sha.Sum(nil)
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objectEncryptionKey := bytes.NewBuffer(nil) // decrypt object encryption key
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n, err := sio.Decrypt(objectEncryptionKey, bytes.NewReader(sealedKey), sio.Config{
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Key: keyEncryptionKey,
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})
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if n != 32 || err != nil {
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// Either the provided key does not match or the object was tampered.
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// To provide strict AWS S3 compatibility we return: access denied.
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return nil, errSSEKeyMismatch
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}
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return objectEncryptionKey.Bytes(), nil
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}
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func newDecryptWriter(client io.Writer, key []byte, seqNumber uint32, metadata map[string]string) (io.WriteCloser, error) {
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objectEncryptionKey, err := decryptObjectInfo(key, metadata)
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if err != nil {
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return nil, err
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}
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return newDecryptWriterWithObjectKey(client, objectEncryptionKey, seqNumber, metadata)
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}
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func newDecryptWriterWithObjectKey(client io.Writer, objectEncryptionKey []byte, seqNumber uint32, metadata map[string]string) (io.WriteCloser, error) {
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writer, err := sio.DecryptWriter(client, sio.Config{
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Key: objectEncryptionKey,
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SequenceNumber: seqNumber,
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})
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if err != nil {
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return nil, errInvalidSSEKey
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}
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delete(metadata, ServerSideEncryptionIV)
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delete(metadata, ServerSideEncryptionSealAlgorithm)
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delete(metadata, ServerSideEncryptionSealedKey)
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delete(metadata, ReservedMetadataPrefix+"Encrypted-Multipart")
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return writer, nil
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}
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// DecryptRequestWithSequenceNumber decrypts the object with the client provided key. It also removes
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// the client-side-encryption metadata from the object and sets the correct headers.
|
|
func DecryptRequestWithSequenceNumber(client io.Writer, r *http.Request, seqNumber uint32, metadata map[string]string) (io.WriteCloser, error) {
|
|
key, err := ParseSSECustomerRequest(r)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
delete(metadata, SSECustomerKey) // make sure we do not save the key by accident
|
|
return newDecryptWriter(client, key, seqNumber, metadata)
|
|
}
|
|
|
|
// DecryptRequest 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 DecryptRequest(client io.Writer, r *http.Request, metadata map[string]string) (io.WriteCloser, error) {
|
|
return DecryptRequestWithSequenceNumber(client, r, 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
|
|
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 {
|
|
w.req.Header.Set(SSECopyCustomerKey, w.customerKeyHeader)
|
|
key, err = ParseSSECopyCustomerRequest(w.req)
|
|
} else {
|
|
w.req.Header.Set(SSECustomerKey, w.customerKeyHeader)
|
|
key, err = ParseSSECustomerRequest(w.req)
|
|
}
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
objectEncryptionKey, err := decryptObjectInfo(key, 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, SSECopyCustomerKey)
|
|
} else {
|
|
delete(m, SSECustomerKey)
|
|
}
|
|
|
|
// 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, objInfo ObjectInfo) (io.WriteCloser, int64, error) {
|
|
w, _, size, err := DecryptBlocksRequest(client, r, 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, startOffset, length int64, objInfo ObjectInfo, copySource bool) (io.WriteCloser, int64, int64, error) {
|
|
seqNumber, encStartOffset, encLength := getEncryptedStartOffset(startOffset, length)
|
|
|
|
// Encryption length cannot be bigger than the file size, if it is
|
|
// which is allowed in AWS S3, we simply default to EncryptedSize().
|
|
if encLength+encStartOffset > objInfo.EncryptedSize() {
|
|
encLength = objInfo.EncryptedSize() - encStartOffset
|
|
}
|
|
|
|
if len(objInfo.Parts) == 0 || !objInfo.IsEncryptedMultipart() {
|
|
var writer io.WriteCloser
|
|
var err error
|
|
if copySource {
|
|
writer, err = DecryptCopyRequest(client, r, objInfo.UserDefined)
|
|
} else {
|
|
writer, err = DecryptRequestWithSequenceNumber(client, r, seqNumber, objInfo.UserDefined)
|
|
}
|
|
if err != nil {
|
|
return nil, 0, 0, err
|
|
}
|
|
return writer, encStartOffset, encLength, nil
|
|
}
|
|
|
|
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,
|
|
customerKeyHeader: r.Header.Get(SSECustomerKey),
|
|
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, ServerSideEncryptionIV)
|
|
delete(objInfo.UserDefined, ServerSideEncryptionSealAlgorithm)
|
|
delete(objInfo.UserDefined, ServerSideEncryptionSealedKey)
|
|
delete(objInfo.UserDefined, ReservedMetadataPrefix+"Encrypted-Multipart")
|
|
|
|
if w.copySource {
|
|
w.customerKeyHeader = r.Header.Get(SSECopyCustomerKey)
|
|
}
|
|
|
|
if err := w.buildDecrypter(partStartIndex + 1); err != nil {
|
|
return nil, 0, 0, err
|
|
}
|
|
|
|
return w, encStartOffset, encLength, nil
|
|
}
|
|
|
|
// getEncryptedStartOffset - fetch sequence number, encrypted start offset and encrypted length.
|
|
func getEncryptedStartOffset(offset, length int64) (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
|
|
}
|
|
|
|
return seqNumber, encOffset, encLength
|
|
}
|
|
|
|
// IsEncryptedMultipart - is the encrypted content multiparted?
|
|
func (o *ObjectInfo) IsEncryptedMultipart() bool {
|
|
_, ok := o.UserDefined[ReservedMetadataPrefix+"Encrypted-Multipart"]
|
|
return ok
|
|
}
|
|
|
|
// IsEncrypted returns true if the object is marked as encrypted.
|
|
func (o *ObjectInfo) IsEncrypted() bool {
|
|
if _, ok := o.UserDefined[ServerSideEncryptionIV]; ok {
|
|
return true
|
|
}
|
|
if _, ok := o.UserDefined[ServerSideEncryptionSealAlgorithm]; ok {
|
|
return true
|
|
}
|
|
if _, ok := o.UserDefined[ServerSideEncryptionSealedKey]; ok {
|
|
return true
|
|
}
|
|
return false
|
|
}
|
|
|
|
// IsEncrypted returns true if the object is marked as encrypted.
|
|
func (li *ListPartsInfo) IsEncrypted() bool {
|
|
if _, ok := li.UserDefined[ServerSideEncryptionIV]; ok {
|
|
return true
|
|
}
|
|
if _, ok := li.UserDefined[ServerSideEncryptionSealAlgorithm]; ok {
|
|
return true
|
|
}
|
|
if _, ok := li.UserDefined[ServerSideEncryptionSealedKey]; ok {
|
|
return true
|
|
}
|
|
return false
|
|
}
|
|
|
|
// 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.
|
|
// DecryptedSize panics if the referred object is not encrypted.
|
|
func (o *ObjectInfo) DecryptedSize() (int64, error) {
|
|
if !o.IsEncrypted() {
|
|
panic("cannot compute decrypted size of an object which is not encrypted")
|
|
}
|
|
size, err := sio.DecryptedSize(uint64(o.Size))
|
|
if err != nil {
|
|
err = errObjectTampered // assign correct error type
|
|
}
|
|
return int64(size), err
|
|
}
|
|
|
|
// 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 {
|
|
panic(err) // Since AWS S3 allows parts to be 5GB at most this cannot happen - sio max. size is 256 TB
|
|
}
|
|
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, info.IsEncrypted(); !encrypted && hasSSECopyCustomerHeader(headers) {
|
|
apiErr = ErrInvalidEncryptionParameters
|
|
} else if encrypted {
|
|
if !hasSSECopyCustomerHeader(headers) {
|
|
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
|
|
}
|
|
if apiErr, encrypted = ErrNone, info.IsEncrypted(); !encrypted && hasSSECustomerHeader(headers) {
|
|
apiErr = ErrInvalidEncryptionParameters
|
|
} else if encrypted {
|
|
if !hasSSECustomerHeader(headers) {
|
|
apiErr = ErrSSEEncryptedObject
|
|
return
|
|
}
|
|
var err error
|
|
if info.Size, err = info.DecryptedSize(); err != nil {
|
|
apiErr = toAPIErrorCode(err)
|
|
}
|
|
}
|
|
return
|
|
}
|