1018 lines
31 KiB
Go
1018 lines
31 KiB
Go
// Copyright 2016 - 2022 The excelize Authors. All rights reserved. Use of
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// this source code is governed by a BSD-style license that can be found in
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// the LICENSE file.
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//
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// Package excelize providing a set of functions that allow you to write to and
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// read from XLAM / XLSM / XLSX / XLTM / XLTX files. Supports reading and
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// writing spreadsheet documents generated by Microsoft Excel™ 2007 and later.
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// Supports complex components by high compatibility, and provided streaming
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// API for generating or reading data from a worksheet with huge amounts of
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// data. This library needs Go version 1.15 or later.
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package excelize
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import (
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"bytes"
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"crypto/aes"
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"crypto/cipher"
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"crypto/md5"
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"crypto/rand"
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"crypto/sha1"
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"crypto/sha256"
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"crypto/sha512"
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"encoding/base64"
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"encoding/binary"
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"encoding/xml"
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"hash"
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"math"
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"path/filepath"
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"reflect"
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"sort"
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"strings"
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"github.com/richardlehane/mscfb"
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"golang.org/x/crypto/md4"
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"golang.org/x/crypto/ripemd160"
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"golang.org/x/text/encoding/unicode"
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)
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var (
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blockKey = []byte{0x14, 0x6e, 0x0b, 0xe7, 0xab, 0xac, 0xd0, 0xd6} // Block keys used for encryption
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oleIdentifier = []byte{0xd0, 0xcf, 0x11, 0xe0, 0xa1, 0xb1, 0x1a, 0xe1}
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headerCLSID = make([]byte, 16)
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difSect = -4
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endOfChain = -2
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fatSect = -3
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iterCount = 50000
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packageEncryptionChunkSize = 4096
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packageOffset = 8 // First 8 bytes are the size of the stream
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sheetProtectionSpinCount = 1e5
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)
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// Encryption specifies the encryption structure, streams, and storages are
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// required when encrypting ECMA-376 documents.
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type Encryption struct {
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XMLName xml.Name `xml:"encryption"`
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KeyData KeyData `xml:"keyData"`
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DataIntegrity DataIntegrity `xml:"dataIntegrity"`
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KeyEncryptors KeyEncryptors `xml:"keyEncryptors"`
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}
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// KeyData specifies the cryptographic attributes used to encrypt the data.
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type KeyData struct {
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SaltSize int `xml:"saltSize,attr"`
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BlockSize int `xml:"blockSize,attr"`
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KeyBits int `xml:"keyBits,attr"`
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HashSize int `xml:"hashSize,attr"`
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CipherAlgorithm string `xml:"cipherAlgorithm,attr"`
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CipherChaining string `xml:"cipherChaining,attr"`
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HashAlgorithm string `xml:"hashAlgorithm,attr"`
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SaltValue string `xml:"saltValue,attr"`
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}
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// DataIntegrity specifies the encrypted copies of the salt and hash values
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// used to help ensure that the integrity of the encrypted data has not been
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// compromised.
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type DataIntegrity struct {
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EncryptedHmacKey string `xml:"encryptedHmacKey,attr"`
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EncryptedHmacValue string `xml:"encryptedHmacValue,attr"`
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}
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// KeyEncryptors specifies the key encryptors used to encrypt the data.
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type KeyEncryptors struct {
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KeyEncryptor []KeyEncryptor `xml:"keyEncryptor"`
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}
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// KeyEncryptor specifies that the schema used by this encryptor is the schema
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// specified for password-based encryptors.
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type KeyEncryptor struct {
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XMLName xml.Name `xml:"keyEncryptor"`
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URI string `xml:"uri,attr"`
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EncryptedKey EncryptedKey `xml:"encryptedKey"`
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}
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// EncryptedKey used to generate the encrypting key.
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type EncryptedKey struct {
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XMLName xml.Name `xml:"http://schemas.microsoft.com/office/2006/keyEncryptor/password encryptedKey"`
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SpinCount int `xml:"spinCount,attr"`
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EncryptedVerifierHashInput string `xml:"encryptedVerifierHashInput,attr"`
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EncryptedVerifierHashValue string `xml:"encryptedVerifierHashValue,attr"`
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EncryptedKeyValue string `xml:"encryptedKeyValue,attr"`
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KeyData
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}
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// StandardEncryptionHeader structure is used by ECMA-376 document encryption
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// [ECMA-376] and Office binary document RC4 CryptoAPI encryption, to specify
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// encryption properties for an encrypted stream.
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type StandardEncryptionHeader struct {
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Flags uint32
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SizeExtra uint32
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AlgID uint32
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AlgIDHash uint32
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KeySize uint32
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ProviderType uint32
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Reserved1 uint32
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Reserved2 uint32
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CspName string
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}
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// StandardEncryptionVerifier structure is used by Office Binary Document RC4
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// CryptoAPI Encryption and ECMA-376 Document Encryption. Every usage of this
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// structure MUST specify the hashing algorithm and encryption algorithm used
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// in the EncryptionVerifier structure.
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type StandardEncryptionVerifier struct {
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SaltSize uint32
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Salt []byte
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EncryptedVerifier []byte
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VerifierHashSize uint32
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EncryptedVerifierHash []byte
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}
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// encryptionInfo structure is used for standard encryption with SHA1
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// cryptographic algorithm.
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type encryption struct {
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BlockSize, SaltSize int
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EncryptedKeyValue, EncryptedVerifierHashInput, EncryptedVerifierHashValue, SaltValue []byte
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KeyBits uint32
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}
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// Decrypt API decrypts the CFB file format with ECMA-376 agile encryption and
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// standard encryption. Support cryptographic algorithm: MD4, MD5, RIPEMD-160,
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// SHA1, SHA256, SHA384 and SHA512 currently.
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func Decrypt(raw []byte, opts *Options) (packageBuf []byte, err error) {
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doc, err := mscfb.New(bytes.NewReader(raw))
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if err != nil {
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return
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}
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encryptionInfoBuf, encryptedPackageBuf := extractPart(doc)
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mechanism, err := encryptionMechanism(encryptionInfoBuf)
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if err != nil || mechanism == "extensible" {
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return
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}
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if mechanism == "agile" {
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return agileDecrypt(encryptionInfoBuf, encryptedPackageBuf, opts)
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}
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return standardDecrypt(encryptionInfoBuf, encryptedPackageBuf, opts)
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}
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// Encrypt API encrypt data with the password.
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func Encrypt(raw []byte, opts *Options) ([]byte, error) {
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encryptor := encryption{
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EncryptedVerifierHashInput: make([]byte, 16),
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EncryptedVerifierHashValue: make([]byte, 32),
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SaltValue: make([]byte, 16),
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BlockSize: 16,
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KeyBits: 128,
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SaltSize: 16,
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}
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// Key Encryption
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encryptionInfoBuffer, err := encryptor.standardKeyEncryption(opts.Password)
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if err != nil {
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return nil, err
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}
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// Package Encryption
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encryptedPackage := make([]byte, 8)
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binary.LittleEndian.PutUint64(encryptedPackage, uint64(len(raw)))
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encryptedPackage = append(encryptedPackage, encryptor.encrypt(raw)...)
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// Create a new CFB
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compoundFile := &cfb{
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paths: []string{"Root Entry/"},
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sectors: []sector{{name: "Root Entry", typeID: 5}},
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}
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compoundFile.put("EncryptionInfo", encryptionInfoBuffer)
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compoundFile.put("EncryptedPackage", encryptedPackage)
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return compoundFile.write(), nil
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}
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// extractPart extract data from storage by specified part name.
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func extractPart(doc *mscfb.Reader) (encryptionInfoBuf, encryptedPackageBuf []byte) {
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for entry, err := doc.Next(); err == nil; entry, err = doc.Next() {
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switch entry.Name {
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case "EncryptionInfo":
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buf := make([]byte, entry.Size)
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i, _ := doc.Read(buf)
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if i > 0 {
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encryptionInfoBuf = buf
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}
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case "EncryptedPackage":
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buf := make([]byte, entry.Size)
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i, _ := doc.Read(buf)
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if i > 0 {
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encryptedPackageBuf = buf
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}
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}
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}
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return
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}
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// encryptionMechanism parse password-protected documents created mechanism.
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func encryptionMechanism(buffer []byte) (mechanism string, err error) {
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if len(buffer) < 4 {
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err = ErrUnknownEncryptMechanism
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return
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}
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versionMajor, versionMinor := binary.LittleEndian.Uint16(buffer[:2]), binary.LittleEndian.Uint16(buffer[2:4])
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if versionMajor == 4 && versionMinor == 4 {
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mechanism = "agile"
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return
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} else if (2 <= versionMajor && versionMajor <= 4) && versionMinor == 2 {
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mechanism = "standard"
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return
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} else if (versionMajor == 3 || versionMajor == 4) && versionMinor == 3 {
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mechanism = "extensible"
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}
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err = ErrUnsupportedEncryptMechanism
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return
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}
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// ECMA-376 Standard Encryption
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// standardDecrypt decrypt the CFB file format with ECMA-376 standard encryption.
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func standardDecrypt(encryptionInfoBuf, encryptedPackageBuf []byte, opts *Options) ([]byte, error) {
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encryptionHeaderSize := binary.LittleEndian.Uint32(encryptionInfoBuf[8:12])
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block := encryptionInfoBuf[12 : 12+encryptionHeaderSize]
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header := StandardEncryptionHeader{
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Flags: binary.LittleEndian.Uint32(block[:4]),
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SizeExtra: binary.LittleEndian.Uint32(block[4:8]),
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AlgID: binary.LittleEndian.Uint32(block[8:12]),
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AlgIDHash: binary.LittleEndian.Uint32(block[12:16]),
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KeySize: binary.LittleEndian.Uint32(block[16:20]),
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ProviderType: binary.LittleEndian.Uint32(block[20:24]),
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Reserved1: binary.LittleEndian.Uint32(block[24:28]),
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Reserved2: binary.LittleEndian.Uint32(block[28:32]),
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CspName: string(block[32:]),
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}
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block = encryptionInfoBuf[12+encryptionHeaderSize:]
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algIDMap := map[uint32]string{
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0x0000660E: "AES-128",
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0x0000660F: "AES-192",
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0x00006610: "AES-256",
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}
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algorithm := "AES"
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_, ok := algIDMap[header.AlgID]
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if !ok {
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algorithm = "RC4"
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}
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verifier := standardEncryptionVerifier(algorithm, block)
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secretKey, err := standardConvertPasswdToKey(header, verifier, opts)
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if err != nil {
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return nil, err
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}
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// decrypted data
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x := encryptedPackageBuf[8:]
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blob, err := aes.NewCipher(secretKey)
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if err != nil {
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return nil, err
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}
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decrypted := make([]byte, len(x))
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size := 16
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for bs, be := 0, size; bs < len(x); bs, be = bs+size, be+size {
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blob.Decrypt(decrypted[bs:be], x[bs:be])
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}
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return decrypted, err
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}
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// standardEncryptionVerifier extract ECMA-376 standard encryption verifier.
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func standardEncryptionVerifier(algorithm string, blob []byte) StandardEncryptionVerifier {
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verifier := StandardEncryptionVerifier{
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SaltSize: binary.LittleEndian.Uint32(blob[:4]),
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Salt: blob[4:20],
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EncryptedVerifier: blob[20:36],
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VerifierHashSize: binary.LittleEndian.Uint32(blob[36:40]),
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}
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if algorithm == "RC4" {
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verifier.EncryptedVerifierHash = blob[40:60]
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} else if algorithm == "AES" {
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verifier.EncryptedVerifierHash = blob[40:72]
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}
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return verifier
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}
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// standardConvertPasswdToKey generate intermediate key from given password.
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func standardConvertPasswdToKey(header StandardEncryptionHeader, verifier StandardEncryptionVerifier, opts *Options) ([]byte, error) {
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encoder := unicode.UTF16(unicode.LittleEndian, unicode.IgnoreBOM).NewEncoder()
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passwordBuffer, err := encoder.Bytes([]byte(opts.Password))
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if err != nil {
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return nil, err
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}
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key := hashing("sha1", verifier.Salt, passwordBuffer)
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for i := 0; i < iterCount; i++ {
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iterator := createUInt32LEBuffer(i, 4)
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key = hashing("sha1", iterator, key)
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}
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var block int
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hFinal := hashing("sha1", key, createUInt32LEBuffer(block, 4))
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cbRequiredKeyLength := int(header.KeySize) / 8
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cbHash := sha1.Size
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buf1 := bytes.Repeat([]byte{0x36}, 64)
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buf1 = append(standardXORBytes(hFinal, buf1[:cbHash]), buf1[cbHash:]...)
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x1 := hashing("sha1", buf1)
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buf2 := bytes.Repeat([]byte{0x5c}, 64)
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buf2 = append(standardXORBytes(hFinal, buf2[:cbHash]), buf2[cbHash:]...)
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x2 := hashing("sha1", buf2)
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x3 := append(x1, x2...)
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keyDerived := x3[:cbRequiredKeyLength]
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return keyDerived, err
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}
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// standardXORBytes perform XOR operations for two bytes slice.
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func standardXORBytes(a, b []byte) []byte {
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r := make([][2]byte, len(a))
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for i, e := range a {
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r[i] = [2]byte{e, b[i]}
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}
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buf := make([]byte, len(a))
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for p, q := range r {
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buf[p] = q[0] ^ q[1]
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}
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return buf
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}
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// encrypt provides a function to encrypt given value with AES cryptographic
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// algorithm.
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func (e *encryption) encrypt(input []byte) []byte {
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inputBytes := len(input)
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if pad := inputBytes % e.BlockSize; pad != 0 {
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inputBytes += e.BlockSize - pad
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}
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var output, chunk []byte
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encryptedChunk := make([]byte, e.BlockSize)
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for i := 0; i < inputBytes; i += e.BlockSize {
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if i+e.BlockSize <= len(input) {
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chunk = input[i : i+e.BlockSize]
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} else {
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chunk = input[i:]
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}
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chunk = append(chunk, make([]byte, e.BlockSize-len(chunk))...)
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c, _ := aes.NewCipher(e.EncryptedKeyValue)
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c.Encrypt(encryptedChunk, chunk)
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output = append(output, encryptedChunk...)
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}
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return output
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}
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// standardKeyEncryption encrypt convert the password to an encryption key.
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func (e *encryption) standardKeyEncryption(password string) ([]byte, error) {
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if len(password) == 0 || len(password) > MaxFieldLength {
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return nil, ErrPasswordLengthInvalid
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}
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var storage cfb
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storage.writeUint16(0x0003)
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storage.writeUint16(0x0002)
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storage.writeUint32(0x24)
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storage.writeUint32(0xA4)
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storage.writeUint32(0x24)
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storage.writeUint32(0x00)
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storage.writeUint32(0x660E)
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storage.writeUint32(0x8004)
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storage.writeUint32(0x80)
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storage.writeUint32(0x18)
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storage.writeUint64(0x00)
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providerName := "Microsoft Enhanced RSA and AES Cryptographic Provider (Prototype)"
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storage.writeStrings(providerName)
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storage.writeUint16(0x00)
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storage.writeUint32(0x10)
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keyDataSaltValue, _ := randomBytes(16)
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verifierHashInput, _ := randomBytes(16)
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e.SaltValue = keyDataSaltValue
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e.EncryptedKeyValue, _ = standardConvertPasswdToKey(
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StandardEncryptionHeader{KeySize: e.KeyBits},
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StandardEncryptionVerifier{Salt: e.SaltValue},
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&Options{Password: password})
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verifierHashInputKey := hashing("sha1", verifierHashInput)
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e.EncryptedVerifierHashInput = e.encrypt(verifierHashInput)
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e.EncryptedVerifierHashValue = e.encrypt(verifierHashInputKey)
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storage.writeBytes(e.SaltValue)
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storage.writeBytes(e.EncryptedVerifierHashInput)
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storage.writeUint32(0x14)
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storage.writeBytes(e.EncryptedVerifierHashValue)
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storage.position = 0
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return storage.stream, nil
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}
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// ECMA-376 Agile Encryption
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// agileDecrypt decrypt the CFB file format with ECMA-376 agile encryption.
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// Support cryptographic algorithm: MD4, MD5, RIPEMD-160, SHA1, SHA256,
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// SHA384 and SHA512.
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func agileDecrypt(encryptionInfoBuf, encryptedPackageBuf []byte, opts *Options) (packageBuf []byte, err error) {
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var encryptionInfo Encryption
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if encryptionInfo, err = parseEncryptionInfo(encryptionInfoBuf[8:]); err != nil {
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return
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}
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// Convert the password into an encryption key.
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key, err := convertPasswdToKey(opts.Password, blockKey, encryptionInfo)
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if err != nil {
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return
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}
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// Use the key to decrypt the package key.
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encryptedKey := encryptionInfo.KeyEncryptors.KeyEncryptor[0].EncryptedKey
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saltValue, err := base64.StdEncoding.DecodeString(encryptedKey.SaltValue)
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if err != nil {
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return
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}
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encryptedKeyValue, err := base64.StdEncoding.DecodeString(encryptedKey.EncryptedKeyValue)
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if err != nil {
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return
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}
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packageKey, _ := decrypt(key, saltValue, encryptedKeyValue)
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// Use the package key to decrypt the package.
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return decryptPackage(packageKey, encryptedPackageBuf, encryptionInfo)
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}
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// convertPasswdToKey convert the password into an encryption key.
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func convertPasswdToKey(passwd string, blockKey []byte, encryption Encryption) (key []byte, err error) {
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var b bytes.Buffer
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saltValue, err := base64.StdEncoding.DecodeString(encryption.KeyEncryptors.KeyEncryptor[0].EncryptedKey.SaltValue)
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if err != nil {
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return
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}
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b.Write(saltValue)
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encoder := unicode.UTF16(unicode.LittleEndian, unicode.IgnoreBOM).NewEncoder()
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passwordBuffer, err := encoder.Bytes([]byte(passwd))
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if err != nil {
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return
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}
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b.Write(passwordBuffer)
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// Generate the initial hash.
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key = hashing(encryption.KeyData.HashAlgorithm, b.Bytes())
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// Now regenerate until spin count.
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for i := 0; i < encryption.KeyEncryptors.KeyEncryptor[0].EncryptedKey.SpinCount; i++ {
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iterator := createUInt32LEBuffer(i, 4)
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key = hashing(encryption.KeyData.HashAlgorithm, iterator, key)
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}
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// Now generate the final hash.
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key = hashing(encryption.KeyData.HashAlgorithm, key, blockKey)
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// Truncate or pad as needed to get to length of keyBits.
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keyBytes := encryption.KeyEncryptors.KeyEncryptor[0].EncryptedKey.KeyBits / 8
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if len(key) < keyBytes {
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tmp := make([]byte, 0x36)
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key = append(key, tmp...)
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} else if len(key) > keyBytes {
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key = key[:keyBytes]
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}
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return
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}
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|
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// hashing data by specified hash algorithm.
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func hashing(hashAlgorithm string, buffer ...[]byte) (key []byte) {
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hashMap := map[string]hash.Hash{
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"md4": md4.New(),
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"md5": md5.New(),
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"ripemd-160": ripemd160.New(),
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"sha1": sha1.New(),
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"sha256": sha256.New(),
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"sha384": sha512.New384(),
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"sha512": sha512.New(),
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}
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handler, ok := hashMap[strings.ToLower(hashAlgorithm)]
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if !ok {
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return key
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}
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for _, buf := range buffer {
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_, _ = handler.Write(buf)
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}
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key = handler.Sum(nil)
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|
return key
|
|
}
|
|
|
|
// createUInt32LEBuffer create buffer with little endian 32-bit unsigned
|
|
// integer.
|
|
func createUInt32LEBuffer(value int, bufferSize int) []byte {
|
|
buf := make([]byte, bufferSize)
|
|
binary.LittleEndian.PutUint32(buf, uint32(value))
|
|
return buf
|
|
}
|
|
|
|
// parseEncryptionInfo parse the encryption info XML into an object.
|
|
func parseEncryptionInfo(encryptionInfo []byte) (encryption Encryption, err error) {
|
|
err = xml.Unmarshal(encryptionInfo, &encryption)
|
|
return
|
|
}
|
|
|
|
// decrypt provides a function to decrypt input by given cipher algorithm,
|
|
// cipher chaining, key and initialization vector.
|
|
func decrypt(key, iv, input []byte) (packageKey []byte, err error) {
|
|
block, err := aes.NewCipher(key)
|
|
if err != nil {
|
|
return input, err
|
|
}
|
|
cipher.NewCBCDecrypter(block, iv).CryptBlocks(input, input)
|
|
return input, nil
|
|
}
|
|
|
|
// decryptPackage decrypt package by given packageKey and encryption
|
|
// info.
|
|
func decryptPackage(packageKey, input []byte, encryption Encryption) (outputChunks []byte, err error) {
|
|
encryptedKey, offset := encryption.KeyData, packageOffset
|
|
var i, start, end int
|
|
var iv, outputChunk []byte
|
|
for end < len(input) {
|
|
start = end
|
|
end = start + packageEncryptionChunkSize
|
|
|
|
if end > len(input) {
|
|
end = len(input)
|
|
}
|
|
// Grab the next chunk
|
|
var inputChunk []byte
|
|
if (end + offset) < len(input) {
|
|
inputChunk = input[start+offset : end+offset]
|
|
} else {
|
|
inputChunk = input[start+offset : end]
|
|
}
|
|
|
|
// Pad the chunk if it is not an integer multiple of the block size
|
|
remainder := len(inputChunk) % encryptedKey.BlockSize
|
|
if remainder != 0 {
|
|
inputChunk = append(inputChunk, make([]byte, encryptedKey.BlockSize-remainder)...)
|
|
}
|
|
// Create the initialization vector
|
|
iv, err = createIV(i, encryption)
|
|
if err != nil {
|
|
return
|
|
}
|
|
// Decrypt the chunk and add it to the array
|
|
outputChunk, err = decrypt(packageKey, iv, inputChunk)
|
|
if err != nil {
|
|
return
|
|
}
|
|
outputChunks = append(outputChunks, outputChunk...)
|
|
i++
|
|
}
|
|
return
|
|
}
|
|
|
|
// createIV create an initialization vector (IV).
|
|
func createIV(blockKey interface{}, encryption Encryption) ([]byte, error) {
|
|
encryptedKey := encryption.KeyData
|
|
// Create the block key from the current index
|
|
var blockKeyBuf []byte
|
|
if reflect.TypeOf(blockKey).Kind() == reflect.Int {
|
|
blockKeyBuf = createUInt32LEBuffer(blockKey.(int), 4)
|
|
} else {
|
|
blockKeyBuf = blockKey.([]byte)
|
|
}
|
|
saltValue, err := base64.StdEncoding.DecodeString(encryptedKey.SaltValue)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
// Create the initialization vector by hashing the salt with the block key.
|
|
// Truncate or pad as needed to meet the block size.
|
|
iv := hashing(encryptedKey.HashAlgorithm, append(saltValue, blockKeyBuf...))
|
|
if len(iv) < encryptedKey.BlockSize {
|
|
tmp := make([]byte, 0x36)
|
|
iv = append(iv, tmp...)
|
|
} else if len(iv) > encryptedKey.BlockSize {
|
|
iv = iv[:encryptedKey.BlockSize]
|
|
}
|
|
return iv, nil
|
|
}
|
|
|
|
// randomBytes returns securely generated random bytes. It will return an
|
|
// error if the system's secure random number generator fails to function
|
|
// correctly, in which case the caller should not continue.
|
|
func randomBytes(n int) ([]byte, error) {
|
|
b := make([]byte, n)
|
|
_, err := rand.Read(b)
|
|
return b, err
|
|
}
|
|
|
|
// ISO Write Protection Method
|
|
|
|
// genISOPasswdHash implements the ISO password hashing algorithm by given
|
|
// plaintext password, name of the cryptographic hash algorithm, salt value
|
|
// and spin count.
|
|
func genISOPasswdHash(passwd, hashAlgorithm, salt string, spinCount int) (hashValue, saltValue string, err error) {
|
|
if len(passwd) < 1 || len(passwd) > MaxFieldLength {
|
|
err = ErrPasswordLengthInvalid
|
|
return
|
|
}
|
|
algorithmName, ok := map[string]string{
|
|
"MD4": "md4",
|
|
"MD5": "md5",
|
|
"SHA-1": "sha1",
|
|
"SHA-256": "sha256",
|
|
"SHA-384": "sha384",
|
|
"SHA-512": "sha512",
|
|
}[hashAlgorithm]
|
|
if !ok {
|
|
err = ErrUnsupportedHashAlgorithm
|
|
return
|
|
}
|
|
var b bytes.Buffer
|
|
s, _ := randomBytes(16)
|
|
if salt != "" {
|
|
if s, err = base64.StdEncoding.DecodeString(salt); err != nil {
|
|
return
|
|
}
|
|
}
|
|
b.Write(s)
|
|
encoder := unicode.UTF16(unicode.LittleEndian, unicode.IgnoreBOM).NewEncoder()
|
|
passwordBuffer, _ := encoder.Bytes([]byte(passwd))
|
|
b.Write(passwordBuffer)
|
|
// Generate the initial hash.
|
|
key := hashing(algorithmName, b.Bytes())
|
|
// Now regenerate until spin count.
|
|
for i := 0; i < spinCount; i++ {
|
|
iterator := createUInt32LEBuffer(i, 4)
|
|
key = hashing(algorithmName, key, iterator)
|
|
}
|
|
hashValue, saltValue = base64.StdEncoding.EncodeToString(key), base64.StdEncoding.EncodeToString(s)
|
|
return
|
|
}
|
|
|
|
// Compound File Binary Implements
|
|
|
|
// cfb structure is used for the compound file binary (CFB) file format writer.
|
|
type cfb struct {
|
|
stream []byte
|
|
position int
|
|
paths []string
|
|
sectors []sector
|
|
}
|
|
|
|
// sector structure used for FAT, directory, miniFAT, and miniStream sectors.
|
|
type sector struct {
|
|
clsID, content []byte
|
|
name string
|
|
C, L, R, color, size, start, state, typeID int
|
|
}
|
|
|
|
// writeBytes write bytes in the stream by a given value with an offset.
|
|
func (c *cfb) writeBytes(value []byte) {
|
|
pos := c.position
|
|
for i := 0; i < len(value); i++ {
|
|
for j := len(c.stream); j <= i+pos; j++ {
|
|
c.stream = append(c.stream, 0)
|
|
}
|
|
c.stream[i+pos] = value[i]
|
|
}
|
|
c.position = pos + len(value)
|
|
}
|
|
|
|
// writeUint16 write an uint16 data type bytes in the stream by a given value
|
|
// with an offset.
|
|
func (c *cfb) writeUint16(value int) {
|
|
buf := make([]byte, 2)
|
|
binary.LittleEndian.PutUint16(buf, uint16(value))
|
|
c.writeBytes(buf)
|
|
}
|
|
|
|
// writeUint32 write an uint32 data type bytes in the stream by a given value
|
|
// with an offset.
|
|
func (c *cfb) writeUint32(value int) {
|
|
buf := make([]byte, 4)
|
|
binary.LittleEndian.PutUint32(buf, uint32(value))
|
|
c.writeBytes(buf)
|
|
}
|
|
|
|
// writeUint64 write an uint64 data type bytes in the stream by a given value
|
|
// with an offset.
|
|
func (c *cfb) writeUint64(value int) {
|
|
buf := make([]byte, 8)
|
|
binary.LittleEndian.PutUint64(buf, uint64(value))
|
|
c.writeBytes(buf)
|
|
}
|
|
|
|
// writeBytes write strings in the stream by a given value with an offset.
|
|
func (c *cfb) writeStrings(value string) {
|
|
encoder := unicode.UTF16(unicode.LittleEndian, unicode.IgnoreBOM).NewEncoder()
|
|
buffer, err := encoder.Bytes([]byte(value))
|
|
if err != nil {
|
|
return
|
|
}
|
|
c.writeBytes(buffer)
|
|
}
|
|
|
|
// put provides a function to add an entry to compound file by given entry name
|
|
// and raw bytes.
|
|
func (c *cfb) put(name string, content []byte) {
|
|
path := c.paths[0]
|
|
if len(path) <= len(name) && name[:len(path)] == path {
|
|
path = name
|
|
} else {
|
|
if len(path) > 0 && string(path[len(path)-1]) != "/" {
|
|
path += "/"
|
|
}
|
|
path = strings.ReplaceAll(path+name, "//", "/")
|
|
}
|
|
file := sector{name: path, typeID: 2, content: content, size: len(content)}
|
|
c.sectors = append(c.sectors, file)
|
|
c.paths = append(c.paths, path)
|
|
}
|
|
|
|
// compare provides a function to compare object path, each set of sibling
|
|
// objects in one level of the containment hierarchy (all child objects under
|
|
// a storage object) is represented as a red-black tree. The parent object of
|
|
// this set of siblings will have a pointer to the top of this tree.
|
|
func (c *cfb) compare(left, right string) int {
|
|
L, R, i, j := strings.Split(left, "/"), strings.Split(right, "/"), 0, 0
|
|
for Z := int(math.Min(float64(len(L)), float64(len(R)))); i < Z; i++ {
|
|
if j = len(L[i]) - len(R[i]); j != 0 {
|
|
return j
|
|
}
|
|
if L[i] != R[i] {
|
|
if L[i] < R[i] {
|
|
return -1
|
|
}
|
|
return 1
|
|
}
|
|
}
|
|
return len(L) - len(R)
|
|
}
|
|
|
|
// prepare provides a function to prepare object before write stream.
|
|
func (c *cfb) prepare() {
|
|
type object struct {
|
|
path string
|
|
sector sector
|
|
}
|
|
var objects []object
|
|
for i := 0; i < len(c.paths); i++ {
|
|
if c.sectors[i].typeID == 0 {
|
|
continue
|
|
}
|
|
objects = append(objects, object{path: c.paths[i], sector: c.sectors[i]})
|
|
}
|
|
sort.Slice(objects, func(i, j int) bool {
|
|
return c.compare(objects[i].path, objects[j].path) == 0
|
|
})
|
|
c.paths, c.sectors = []string{}, []sector{}
|
|
for i := 0; i < len(objects); i++ {
|
|
c.paths = append(c.paths, objects[i].path)
|
|
c.sectors = append(c.sectors, objects[i].sector)
|
|
}
|
|
for i := 0; i < len(objects); i++ {
|
|
sector, path := &c.sectors[i], c.paths[i]
|
|
sector.name, sector.color = filepath.Base(path), 1
|
|
sector.L, sector.R, sector.C = -1, -1, -1
|
|
sector.size, sector.start = len(sector.content), 0
|
|
if len(sector.clsID) == 0 {
|
|
sector.clsID = headerCLSID
|
|
}
|
|
if i == 0 {
|
|
sector.C = -1
|
|
if len(objects) > 1 {
|
|
sector.C = 1
|
|
}
|
|
sector.size, sector.typeID = 0, 5
|
|
} else {
|
|
if len(c.paths) > i+1 && filepath.Dir(c.paths[i+1]) == filepath.Dir(path) {
|
|
sector.R = i + 1
|
|
}
|
|
sector.typeID = 2
|
|
}
|
|
}
|
|
}
|
|
|
|
// locate provides a function to locate sectors location and size of the
|
|
// compound file.
|
|
func (c *cfb) locate() []int {
|
|
var miniStreamSectorSize, FATSectorSize int
|
|
for i := 0; i < len(c.sectors); i++ {
|
|
sector := c.sectors[i]
|
|
if len(sector.content) == 0 {
|
|
continue
|
|
}
|
|
size := len(sector.content)
|
|
if size > 0 {
|
|
if size < 0x1000 {
|
|
miniStreamSectorSize += (size + 0x3F) >> 6
|
|
} else {
|
|
FATSectorSize += (size + 0x01FF) >> 9
|
|
}
|
|
}
|
|
}
|
|
directorySectors := (len(c.paths) + 3) >> 2
|
|
miniStreamSectors := (miniStreamSectorSize + 7) >> 3
|
|
miniFATSectors := (miniStreamSectorSize + 0x7F) >> 7
|
|
sectors := miniStreamSectors + FATSectorSize + directorySectors + miniFATSectors
|
|
FATSectors := (sectors + 0x7F) >> 7
|
|
DIFATSectors := 0
|
|
if FATSectors > 109 {
|
|
DIFATSectors = int(math.Ceil((float64(FATSectors) - 109) / 0x7F))
|
|
}
|
|
for ((sectors + FATSectors + DIFATSectors + 0x7F) >> 7) > FATSectors {
|
|
FATSectors++
|
|
if FATSectors <= 109 {
|
|
DIFATSectors = 0
|
|
} else {
|
|
DIFATSectors = int(math.Ceil((float64(FATSectors) - 109) / 0x7F))
|
|
}
|
|
}
|
|
location := []int{1, DIFATSectors, FATSectors, miniFATSectors, directorySectors, FATSectorSize, miniStreamSectorSize, 0}
|
|
c.sectors[0].size = miniStreamSectorSize << 6
|
|
c.sectors[0].start = location[0] + location[1] + location[2] + location[3] + location[4] + location[5]
|
|
location[7] = c.sectors[0].start + ((location[6] + 7) >> 3)
|
|
return location
|
|
}
|
|
|
|
// writeMSAT provides a function to write compound file master sector allocation
|
|
// table.
|
|
func (c *cfb) writeMSAT(location []int) {
|
|
var i, offset int
|
|
for i = 0; i < 109; i++ {
|
|
if i < location[2] {
|
|
c.writeUint32(location[1] + i)
|
|
} else {
|
|
c.writeUint32(-1)
|
|
}
|
|
}
|
|
if location[1] != 0 {
|
|
for offset = 0; offset < location[1]; offset++ {
|
|
for ; i < 236+offset*127; i++ {
|
|
if i < location[2] {
|
|
c.writeUint32(location[1] + i)
|
|
} else {
|
|
c.writeUint32(-1)
|
|
}
|
|
}
|
|
if offset == location[1]-1 {
|
|
c.writeUint32(endOfChain)
|
|
} else {
|
|
c.writeUint32(offset + 1)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// writeDirectoryEntry provides a function to write compound file directory
|
|
// entries. The directory entry array is an array of directory entries that
|
|
// are grouped into a directory sector. Each storage object or stream object
|
|
// within a compound file is represented by a single directory entry. The
|
|
// space for the directory sectors that are holding the array is allocated
|
|
// from the FAT.
|
|
func (c *cfb) writeDirectoryEntry(location []int) {
|
|
var sector sector
|
|
var j, sectorSize int
|
|
for i := 0; i < location[4]<<2; i++ {
|
|
var path string
|
|
if i < len(c.paths) {
|
|
path = c.paths[i]
|
|
}
|
|
if i >= len(c.paths) || len(path) == 0 {
|
|
for j = 0; j < 17; j++ {
|
|
c.writeUint32(0)
|
|
}
|
|
for j = 0; j < 3; j++ {
|
|
c.writeUint32(-1)
|
|
}
|
|
for j = 0; j < 12; j++ {
|
|
c.writeUint32(0)
|
|
}
|
|
continue
|
|
}
|
|
sector = c.sectors[i]
|
|
if i == 0 {
|
|
if sector.size > 0 {
|
|
sector.start = sector.start - 1
|
|
} else {
|
|
sector.start = endOfChain
|
|
}
|
|
}
|
|
name := sector.name
|
|
sectorSize = 2 * (len(name) + 1)
|
|
c.writeStrings(name)
|
|
c.position += 64 - 2*(len(name))
|
|
c.writeUint16(sectorSize)
|
|
c.writeBytes([]byte(string(rune(sector.typeID))))
|
|
c.writeBytes([]byte(string(rune(sector.color))))
|
|
c.writeUint32(sector.L)
|
|
c.writeUint32(sector.R)
|
|
c.writeUint32(sector.C)
|
|
if len(sector.clsID) == 0 {
|
|
for j = 0; j < 4; j++ {
|
|
c.writeUint32(0)
|
|
}
|
|
} else {
|
|
c.writeBytes(sector.clsID)
|
|
}
|
|
c.writeUint32(sector.state)
|
|
c.writeUint32(0)
|
|
c.writeUint32(0)
|
|
c.writeUint32(0)
|
|
c.writeUint32(0)
|
|
c.writeUint32(sector.start)
|
|
c.writeUint32(sector.size)
|
|
c.writeUint32(0)
|
|
}
|
|
}
|
|
|
|
// writeSectorChains provides a function to write compound file sector chains.
|
|
func (c *cfb) writeSectorChains(location []int) sector {
|
|
var i, j, offset, sectorSize int
|
|
writeSectorChain := func(head, offset int) int {
|
|
for offset += head; i < offset-1; i++ {
|
|
c.writeUint32(i + 1)
|
|
}
|
|
if head != 0 {
|
|
i++
|
|
c.writeUint32(endOfChain)
|
|
}
|
|
return offset
|
|
}
|
|
for offset += location[1]; i < offset; i++ {
|
|
c.writeUint32(difSect)
|
|
}
|
|
for offset += location[2]; i < offset; i++ {
|
|
c.writeUint32(fatSect)
|
|
}
|
|
offset = writeSectorChain(location[3], offset)
|
|
offset = writeSectorChain(location[4], offset)
|
|
sector := c.sectors[0]
|
|
for ; j < len(c.sectors); j++ {
|
|
if sector = c.sectors[j]; len(sector.content) == 0 {
|
|
continue
|
|
}
|
|
if sectorSize = len(sector.content); sectorSize < 0x1000 {
|
|
continue
|
|
}
|
|
c.sectors[j].start = offset
|
|
offset = writeSectorChain((sectorSize+0x01FF)>>9, offset)
|
|
}
|
|
writeSectorChain((location[6]+7)>>3, offset)
|
|
for c.position&0x1FF != 0 {
|
|
c.writeUint32(endOfChain)
|
|
}
|
|
i, offset = 0, 0
|
|
for j = 0; j < len(c.sectors); j++ {
|
|
if sector = c.sectors[j]; len(sector.content) == 0 {
|
|
continue
|
|
}
|
|
if sectorSize = len(sector.content); sectorSize == 0 || sectorSize >= 0x1000 {
|
|
continue
|
|
}
|
|
sector.start = offset
|
|
offset = writeSectorChain((sectorSize+0x3F)>>6, offset)
|
|
}
|
|
for c.position&0x1FF != 0 {
|
|
c.writeUint32(endOfChain)
|
|
}
|
|
return sector
|
|
}
|
|
|
|
// write provides a function to create compound file package stream.
|
|
func (c *cfb) write() []byte {
|
|
c.prepare()
|
|
location := c.locate()
|
|
c.stream = make([]byte, location[7]<<9)
|
|
var i, j int
|
|
for i = 0; i < 8; i++ {
|
|
c.writeBytes([]byte{oleIdentifier[i]})
|
|
}
|
|
c.writeBytes(make([]byte, 16))
|
|
c.writeUint16(0x003E)
|
|
c.writeUint16(0x0003)
|
|
c.writeUint16(0xFFFE)
|
|
c.writeUint16(0x0009)
|
|
c.writeUint16(0x0006)
|
|
c.writeBytes(make([]byte, 10))
|
|
c.writeUint32(location[2])
|
|
c.writeUint32(location[0] + location[1] + location[2] + location[3] - 1)
|
|
c.writeUint32(0)
|
|
c.writeUint32(1 << 12)
|
|
if location[3] != 0 {
|
|
c.writeUint32(location[0] + location[1] + location[2] - 1)
|
|
} else {
|
|
c.writeUint32(endOfChain)
|
|
}
|
|
c.writeUint32(location[3])
|
|
if location[1] != 0 {
|
|
c.writeUint32(location[0] - 1)
|
|
} else {
|
|
c.writeUint32(endOfChain)
|
|
}
|
|
c.writeUint32(location[1])
|
|
c.writeMSAT(location)
|
|
sector := c.writeSectorChains(location)
|
|
c.writeDirectoryEntry(location)
|
|
for i = 1; i < len(c.sectors); i++ {
|
|
sector = c.sectors[i]
|
|
if sector.size >= 0x1000 {
|
|
c.position = (sector.start + 1) << 9
|
|
for j = 0; j < sector.size; j++ {
|
|
c.writeBytes([]byte{sector.content[j]})
|
|
}
|
|
for ; j&0x1FF != 0; j++ {
|
|
c.writeBytes([]byte{0})
|
|
}
|
|
}
|
|
}
|
|
for i = 1; i < len(c.sectors); i++ {
|
|
sector = c.sectors[i]
|
|
if sector.size > 0 && sector.size < 0x1000 {
|
|
for j = 0; j < sector.size; j++ {
|
|
c.writeBytes([]byte{sector.content[j]})
|
|
}
|
|
for ; j&0x3F != 0; j++ {
|
|
c.writeBytes([]byte{0})
|
|
}
|
|
}
|
|
}
|
|
for c.position < len(c.stream) {
|
|
c.writeBytes([]byte{0})
|
|
}
|
|
return c.stream
|
|
}
|