feat(QMCv2): support static cipher (legacy)

This commit is contained in:
MengYX 2021-12-14 02:19:32 +08:00
parent 1025010395
commit 7cc7aa19fd
No known key found for this signature in database
GPG Key ID: E63F9C7303E8F604
7 changed files with 157 additions and 42 deletions

57
algo/qmc/cipher_static.go Normal file
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@ -0,0 +1,57 @@
package qmc
func NewStaticCipher() *staticCipher {
return &defaultStaticCipher
}
var defaultStaticCipher = staticCipher{}
type staticCipher struct{}
func (c *staticCipher) Decrypt(buf []byte, offset int) {
for i := 0; i < len(buf); i++ {
buf[i] ^= c.getMask(offset + i)
}
}
func (c *staticCipher) getMask(offset int) byte {
if offset > 0x7FFF {
offset %= 0x7FFF
}
idx := (offset*offset + 27) & 0xff
return staticCipherBox[idx]
}
var staticCipherBox = [...]byte{
0x77, 0x48, 0x32, 0x73, 0xDE, 0xF2, 0xC0, 0xC8, //0x00
0x95, 0xEC, 0x30, 0xB2, 0x51, 0xC3, 0xE1, 0xA0, //0x08
0x9E, 0xE6, 0x9D, 0xCF, 0xFA, 0x7F, 0x14, 0xD1, //0x10
0xCE, 0xB8, 0xDC, 0xC3, 0x4A, 0x67, 0x93, 0xD6, //0x18
0x28, 0xC2, 0x91, 0x70, 0xCA, 0x8D, 0xA2, 0xA4, //0x20
0xF0, 0x08, 0x61, 0x90, 0x7E, 0x6F, 0xA2, 0xE0, //0x28
0xEB, 0xAE, 0x3E, 0xB6, 0x67, 0xC7, 0x92, 0xF4, //0x30
0x91, 0xB5, 0xF6, 0x6C, 0x5E, 0x84, 0x40, 0xF7, //0x38
0xF3, 0x1B, 0x02, 0x7F, 0xD5, 0xAB, 0x41, 0x89, //0x40
0x28, 0xF4, 0x25, 0xCC, 0x52, 0x11, 0xAD, 0x43, //0x48
0x68, 0xA6, 0x41, 0x8B, 0x84, 0xB5, 0xFF, 0x2C, //0x50
0x92, 0x4A, 0x26, 0xD8, 0x47, 0x6A, 0x7C, 0x95, //0x58
0x61, 0xCC, 0xE6, 0xCB, 0xBB, 0x3F, 0x47, 0x58, //0x60
0x89, 0x75, 0xC3, 0x75, 0xA1, 0xD9, 0xAF, 0xCC, //0x68
0x08, 0x73, 0x17, 0xDC, 0xAA, 0x9A, 0xA2, 0x16, //0x70
0x41, 0xD8, 0xA2, 0x06, 0xC6, 0x8B, 0xFC, 0x66, //0x78
0x34, 0x9F, 0xCF, 0x18, 0x23, 0xA0, 0x0A, 0x74, //0x80
0xE7, 0x2B, 0x27, 0x70, 0x92, 0xE9, 0xAF, 0x37, //0x88
0xE6, 0x8C, 0xA7, 0xBC, 0x62, 0x65, 0x9C, 0xC2, //0x90
0x08, 0xC9, 0x88, 0xB3, 0xF3, 0x43, 0xAC, 0x74, //0x98
0x2C, 0x0F, 0xD4, 0xAF, 0xA1, 0xC3, 0x01, 0x64, //0xA0
0x95, 0x4E, 0x48, 0x9F, 0xF4, 0x35, 0x78, 0x95, //0xA8
0x7A, 0x39, 0xD6, 0x6A, 0xA0, 0x6D, 0x40, 0xE8, //0xB0
0x4F, 0xA8, 0xEF, 0x11, 0x1D, 0xF3, 0x1B, 0x3F, //0xB8
0x3F, 0x07, 0xDD, 0x6F, 0x5B, 0x19, 0x30, 0x19, //0xC0
0xFB, 0xEF, 0x0E, 0x37, 0xF0, 0x0E, 0xCD, 0x16, //0xC8
0x49, 0xFE, 0x53, 0x47, 0x13, 0x1A, 0xBD, 0xA4, //0xD0
0xF1, 0x40, 0x19, 0x60, 0x0E, 0xED, 0x68, 0x09, //0xD8
0x06, 0x5F, 0x4D, 0xCF, 0x3D, 0x1A, 0xFE, 0x20, //0xE0
0x77, 0xE4, 0xD9, 0xDA, 0xF9, 0xA4, 0x2B, 0x76, //0xE8
0x1C, 0x71, 0xDB, 0x00, 0xBC, 0xFD, 0x0C, 0x6C, //0xF0
0xA5, 0x47, 0xF7, 0xF6, 0x00, 0x79, 0x4A, 0x11, //0xF8
}

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@ -4,6 +4,7 @@ import (
"encoding/base64" "encoding/base64"
"encoding/binary" "encoding/binary"
"errors" "errors"
"github.com/unlock-music/cli/algo/common" "github.com/unlock-music/cli/algo/common"
) )
@ -13,7 +14,7 @@ var (
ErrQmcKeyLength = errors.New("unexpected decoded qmc key length") ErrQmcKeyLength = errors.New("unexpected decoded qmc key length")
) )
type Decoder struct { type OldDecoder struct {
file []byte file []byte
maskDetector func(encodedData []byte) (*Key256Mask, error) maskDetector func(encodedData []byte) (*Key256Mask, error)
mask *Key256Mask mask *Key256Mask
@ -23,14 +24,14 @@ type Decoder struct {
} }
func NewMflac256Decoder(data []byte) common.Decoder { func NewMflac256Decoder(data []byte) common.Decoder {
return &Decoder{file: data, maskDetector: detectMflac256Mask, audioExt: "flac"} return &OldDecoder{file: data, maskDetector: detectMflac256Mask, audioExt: "flac"}
} }
func NewMgg256Decoder(data []byte) common.Decoder { func NewMgg256Decoder(data []byte) common.Decoder {
return &Decoder{file: data, maskDetector: detectMgg256Mask, audioExt: "ogg"} return &OldDecoder{file: data, maskDetector: detectMgg256Mask, audioExt: "ogg"}
} }
func (d *Decoder) Validate() error { func (d *OldDecoder) Validate() error {
if nil != d.mask { if nil != d.mask {
return nil return nil
} }
@ -45,7 +46,7 @@ func (d *Decoder) Validate() error {
return errors.New("no mask or mask detector found") return errors.New("no mask or mask detector found")
} }
func (d *Decoder) validateKey() error { func (d *OldDecoder) validateKey() error {
lenData := len(d.file) lenData := len(d.file)
if lenData < 4 { if lenData < 4 {
return ErrQmcFileLength return ErrQmcFileLength
@ -70,33 +71,33 @@ func (d *Decoder) validateKey() error {
} }
func (d *Decoder) Decode() error { func (d *OldDecoder) Decode() error {
d.audio = d.mask.Decrypt(d.file) d.audio = d.mask.Decrypt(d.file)
return nil return nil
} }
func (d Decoder) GetCoverImage() []byte { func (d OldDecoder) GetCoverImage() []byte {
return nil return nil
} }
func (d Decoder) GetAudioData() []byte { func (d OldDecoder) GetAudioData() []byte {
return d.audio return d.audio
} }
func (d Decoder) GetAudioExt() string { func (d OldDecoder) GetAudioExt() string {
if d.audioExt != "" { if d.audioExt != "" {
return "." + d.audioExt return "." + d.audioExt
} }
return "" return ""
} }
func (d Decoder) GetMeta() common.Meta { func (d OldDecoder) GetMeta() common.Meta {
return nil return nil
} }
func DecoderFuncWithExt(ext string) common.NewDecoderFunc { func DecoderFuncWithExt(ext string) common.NewDecoderFunc {
return func(file []byte) common.Decoder { return func(file []byte) common.Decoder {
return &Decoder{file: file, audioExt: ext, mask: getDefaultMask()} return &OldDecoder{file: file, audioExt: ext, mask: getDefaultMask()}
} }
} }

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@ -6,10 +6,13 @@ import (
"io" "io"
"strconv" "strconv"
"strings" "strings"
"github.com/unlock-music/cli/algo/common"
) )
type Mflac0Decoder struct { type Decoder struct {
r io.ReadSeeker r io.ReadSeeker
fileExt string
audioLen int audioLen int
decodedKey []byte decodedKey []byte
@ -20,15 +23,9 @@ type Mflac0Decoder struct {
rawMetaExtra2 int rawMetaExtra2 int
} }
func (d *Mflac0Decoder) Read(p []byte) (int, error) { // Read implements io.Reader, offer the decrypted audio data.
if d.cipher != nil { // Validate should call before Read to check if the file is valid.
return d.readRC4(p) func (d *Decoder) Read(p []byte) (int, error) {
} else {
panic("not impl")
//return d.readPlain(p)
}
}
func (d *Mflac0Decoder) readRC4(p []byte) (int, error) {
n := len(p) n := len(p)
if d.audioLen-d.offset <= 0 { if d.audioLen-d.offset <= 0 {
return 0, io.EOF return 0, io.EOF
@ -45,25 +42,25 @@ func (d *Mflac0Decoder) readRC4(p []byte) (int, error) {
return m, err return m, err
} }
func NewMflac0Decoder(r io.ReadSeeker) (*Mflac0Decoder, error) { func NewDecoder(r io.ReadSeeker) (*Decoder, error) {
d := &Mflac0Decoder{r: r} d := &Decoder{r: r}
err := d.searchKey() err := d.searchKey()
if err != nil { if err != nil {
return nil, err return nil, err
} }
if len(d.decodedKey) == 0 { if len(d.decodedKey) > 300 {
return nil, errors.New("invalid decoded key")
} else if len(d.decodedKey) > 300 {
d.cipher, err = NewRC4Cipher(d.decodedKey) d.cipher, err = NewRC4Cipher(d.decodedKey)
if err != nil { if err != nil {
return nil, err return nil, err
} }
} else { } else if len(d.decodedKey) != 0 {
d.cipher, err = NewMapCipher(d.decodedKey) d.cipher, err = NewMapCipher(d.decodedKey)
if err != nil { if err != nil {
return nil, err return nil, err
} }
} else {
d.cipher = NewStaticCipher()
} }
_, err = d.r.Seek(0, io.SeekStart) _, err = d.r.Seek(0, io.SeekStart)
@ -74,8 +71,32 @@ func NewMflac0Decoder(r io.ReadSeeker) (*Mflac0Decoder, error) {
return d, nil return d, nil
} }
func (d *Mflac0Decoder) searchKey() error { func (d *Decoder) Validate() error {
if _, err := d.r.Seek(-4, io.SeekEnd); err != nil { buf := make([]byte, 16)
if _, err := io.ReadFull(d.r, buf); err != nil {
return err
}
_, err := d.r.Seek(0, io.SeekStart)
if err != nil {
return err
}
d.cipher.Decrypt(buf, 0)
fileExt, ok := common.SniffAll(buf)
if !ok {
return errors.New("detect file type failed")
}
d.fileExt = fileExt
return nil
}
func (d Decoder) GetFileExt() string {
return d.fileExt
}
func (d *Decoder) searchKey() error {
fileSizeM4, err := d.r.Seek(-4, io.SeekEnd)
if err != nil {
return err return err
} }
buf, err := io.ReadAll(io.LimitReader(d.r, 4)) buf, err := io.ReadAll(io.LimitReader(d.r, 4))
@ -88,17 +109,18 @@ func (d *Mflac0Decoder) searchKey() error {
} }
} else { } else {
size := binary.LittleEndian.Uint32(buf) size := binary.LittleEndian.Uint32(buf)
if size < 0x300 { if size < 0x300 && size != 0 {
return d.readRawKey(int64(size)) return d.readRawKey(int64(size))
} else { } else {
// todo: try to use fixed key // try to use default static cipher
panic("not impl") d.audioLen = int(fileSizeM4 + 4)
return nil
} }
} }
return nil return nil
} }
func (d *Mflac0Decoder) readRawKey(rawKeyLen int64) error { func (d *Decoder) readRawKey(rawKeyLen int64) error {
audioLen, err := d.r.Seek(-(4 + rawKeyLen), io.SeekEnd) audioLen, err := d.r.Seek(-(4 + rawKeyLen), io.SeekEnd)
if err != nil { if err != nil {
return err return err
@ -118,7 +140,7 @@ func (d *Mflac0Decoder) readRawKey(rawKeyLen int64) error {
return nil return nil
} }
func (d *Mflac0Decoder) readRawMetaQTag() error { func (d *Decoder) readRawMetaQTag() error {
// get raw meta data len // get raw meta data len
if _, err := d.r.Seek(-8, io.SeekEnd); err != nil { if _, err := d.r.Seek(-8, io.SeekEnd); err != nil {
return err return err

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@ -28,24 +28,25 @@ func loadTestDataQmcDecoder(filename string) ([]byte, []byte, error) {
} }
func TestMflac0Decoder_Read(t *testing.T) { func TestMflac0Decoder_Read(t *testing.T) {
tests := []struct { tests := []struct {
name string name string
filename string wantErr bool
wantErr bool
}{ }{
{"mflac0_rc4(512)", "mflac0_rc4", false}, {"mflac0_rc4", false},
{"mflac_map(256)", "mflac_map", false}, {"mflac_map", false},
{"qmc0_static", false},
} }
for _, tt := range tests { for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) { t.Run(tt.name, func(t *testing.T) {
raw, target, err := loadTestDataQmcDecoder(tt.filename) raw, target, err := loadTestDataQmcDecoder(tt.name)
if err != nil { if err != nil {
t.Fatal(err) t.Fatal(err)
} }
d, err := NewMflac0Decoder(bytes.NewReader(raw)) d, err := NewDecoder(bytes.NewReader(raw))
if err != nil { if err != nil {
t.Error(err) t.Error(err)
return
} }
buf := make([]byte, len(target)) buf := make([]byte, len(target))
if _, err := io.ReadFull(d, buf); err != nil { if _, err := io.ReadFull(d, buf); err != nil {
@ -59,3 +60,37 @@ func TestMflac0Decoder_Read(t *testing.T) {
} }
} }
func TestMflac0Decoder_Validate(t *testing.T) {
tests := []struct {
name string
fileExt string
wantErr bool
}{
{"mflac0_rc4", ".flac", false},
{"mflac_map", ".flac", false},
{"qmc0_static", ".mp3", false},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
raw, _, err := loadTestDataQmcDecoder(tt.name)
if err != nil {
t.Fatal(err)
}
d, err := NewDecoder(bytes.NewReader(raw))
if err != nil {
t.Error(err)
return
}
if err := d.Validate(); err != nil {
t.Errorf("read bytes from decoder error = %v", err)
return
}
if tt.fileExt != d.GetFileExt() {
t.Errorf("Decrypt() got = %v, want %v", d.GetFileExt(), tt.fileExt)
}
})
}
}

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algo/qmc/testdata/qmc0_static_raw.bin vendored Normal file

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algo/qmc/testdata/qmc0_static_target.bin vendored Normal file

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