diff --git a/algo/qmc/cipher_static.go b/algo/qmc/cipher_static.go new file mode 100644 index 0000000..f6db30b --- /dev/null +++ b/algo/qmc/cipher_static.go @@ -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 +} diff --git a/algo/qmc/old_qmc.go b/algo/qmc/old_qmc.go index ed284c5..54d9df0 100644 --- a/algo/qmc/old_qmc.go +++ b/algo/qmc/old_qmc.go @@ -4,6 +4,7 @@ import ( "encoding/base64" "encoding/binary" "errors" + "github.com/unlock-music/cli/algo/common" ) @@ -13,7 +14,7 @@ var ( ErrQmcKeyLength = errors.New("unexpected decoded qmc key length") ) -type Decoder struct { +type OldDecoder struct { file []byte maskDetector func(encodedData []byte) (*Key256Mask, error) mask *Key256Mask @@ -23,14 +24,14 @@ type Decoder struct { } 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 { - 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 { return nil } @@ -45,7 +46,7 @@ func (d *Decoder) Validate() error { return errors.New("no mask or mask detector found") } -func (d *Decoder) validateKey() error { +func (d *OldDecoder) validateKey() error { lenData := len(d.file) if lenData < 4 { 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) return nil } -func (d Decoder) GetCoverImage() []byte { +func (d OldDecoder) GetCoverImage() []byte { return nil } -func (d Decoder) GetAudioData() []byte { +func (d OldDecoder) GetAudioData() []byte { return d.audio } -func (d Decoder) GetAudioExt() string { +func (d OldDecoder) GetAudioExt() string { if d.audioExt != "" { return "." + d.audioExt } return "" } -func (d Decoder) GetMeta() common.Meta { +func (d OldDecoder) GetMeta() common.Meta { return nil } func DecoderFuncWithExt(ext string) common.NewDecoderFunc { return func(file []byte) common.Decoder { - return &Decoder{file: file, audioExt: ext, mask: getDefaultMask()} + return &OldDecoder{file: file, audioExt: ext, mask: getDefaultMask()} } } diff --git a/algo/qmc/qmc_512.go b/algo/qmc/qmc.go similarity index 65% rename from algo/qmc/qmc_512.go rename to algo/qmc/qmc.go index fe37c47..61a591e 100644 --- a/algo/qmc/qmc_512.go +++ b/algo/qmc/qmc.go @@ -6,10 +6,13 @@ import ( "io" "strconv" "strings" + + "github.com/unlock-music/cli/algo/common" ) -type Mflac0Decoder struct { - r io.ReadSeeker +type Decoder struct { + r io.ReadSeeker + fileExt string audioLen int decodedKey []byte @@ -20,15 +23,9 @@ type Mflac0Decoder struct { rawMetaExtra2 int } -func (d *Mflac0Decoder) Read(p []byte) (int, error) { - if d.cipher != nil { - return d.readRC4(p) - } else { - panic("not impl") - //return d.readPlain(p) - } -} -func (d *Mflac0Decoder) readRC4(p []byte) (int, error) { +// Read implements io.Reader, offer the decrypted audio data. +// Validate should call before Read to check if the file is valid. +func (d *Decoder) Read(p []byte) (int, error) { n := len(p) if d.audioLen-d.offset <= 0 { return 0, io.EOF @@ -45,25 +42,25 @@ func (d *Mflac0Decoder) readRC4(p []byte) (int, error) { return m, err } -func NewMflac0Decoder(r io.ReadSeeker) (*Mflac0Decoder, error) { - d := &Mflac0Decoder{r: r} +func NewDecoder(r io.ReadSeeker) (*Decoder, error) { + d := &Decoder{r: r} err := d.searchKey() if err != nil { return nil, err } - if len(d.decodedKey) == 0 { - return nil, errors.New("invalid decoded key") - } else if len(d.decodedKey) > 300 { + if len(d.decodedKey) > 300 { d.cipher, err = NewRC4Cipher(d.decodedKey) if err != nil { return nil, err } - } else { + } else if len(d.decodedKey) != 0 { d.cipher, err = NewMapCipher(d.decodedKey) if err != nil { return nil, err } + } else { + d.cipher = NewStaticCipher() } _, err = d.r.Seek(0, io.SeekStart) @@ -74,8 +71,32 @@ func NewMflac0Decoder(r io.ReadSeeker) (*Mflac0Decoder, error) { return d, nil } -func (d *Mflac0Decoder) searchKey() error { - if _, err := d.r.Seek(-4, io.SeekEnd); err != nil { +func (d *Decoder) Validate() error { + 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 } buf, err := io.ReadAll(io.LimitReader(d.r, 4)) @@ -88,17 +109,18 @@ func (d *Mflac0Decoder) searchKey() error { } } else { size := binary.LittleEndian.Uint32(buf) - if size < 0x300 { + if size < 0x300 && size != 0 { return d.readRawKey(int64(size)) } else { - // todo: try to use fixed key - panic("not impl") + // try to use default static cipher + d.audioLen = int(fileSizeM4 + 4) + 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) if err != nil { return err @@ -118,7 +140,7 @@ func (d *Mflac0Decoder) readRawKey(rawKeyLen int64) error { return nil } -func (d *Mflac0Decoder) readRawMetaQTag() error { +func (d *Decoder) readRawMetaQTag() error { // get raw meta data len if _, err := d.r.Seek(-8, io.SeekEnd); err != nil { return err diff --git a/algo/qmc/qmc_512_test.go b/algo/qmc/qmc_test.go similarity index 53% rename from algo/qmc/qmc_512_test.go rename to algo/qmc/qmc_test.go index b2bfd50..f8fd0bf 100644 --- a/algo/qmc/qmc_512_test.go +++ b/algo/qmc/qmc_test.go @@ -28,24 +28,25 @@ func loadTestDataQmcDecoder(filename string) ([]byte, []byte, error) { } func TestMflac0Decoder_Read(t *testing.T) { tests := []struct { - name string - filename string - wantErr bool + name string + wantErr bool }{ - {"mflac0_rc4(512)", "mflac0_rc4", false}, - {"mflac_map(256)", "mflac_map", false}, + {"mflac0_rc4", false}, + {"mflac_map", false}, + {"qmc0_static", false}, } for _, tt := range tests { t.Run(tt.name, func(t *testing.T) { - raw, target, err := loadTestDataQmcDecoder(tt.filename) + raw, target, err := loadTestDataQmcDecoder(tt.name) if err != nil { t.Fatal(err) } - d, err := NewMflac0Decoder(bytes.NewReader(raw)) + d, err := NewDecoder(bytes.NewReader(raw)) if err != nil { t.Error(err) + return } buf := make([]byte, len(target)) 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) + } + }) + } +} diff --git a/algo/qmc/testdata/qmc0_static_raw.bin b/algo/qmc/testdata/qmc0_static_raw.bin new file mode 100644 index 0000000..80f65f9 Binary files /dev/null and b/algo/qmc/testdata/qmc0_static_raw.bin differ diff --git a/algo/qmc/testdata/qmc0_static_suffix.bin b/algo/qmc/testdata/qmc0_static_suffix.bin new file mode 100644 index 0000000..e69de29 diff --git a/algo/qmc/testdata/qmc0_static_target.bin b/algo/qmc/testdata/qmc0_static_target.bin new file mode 100644 index 0000000..f3ff0a4 Binary files /dev/null and b/algo/qmc/testdata/qmc0_static_target.bin differ