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fix(QMCv2): cipher should determine by key size

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(cherry picked from commit dba63f212cbf9351e5dc16870eb32ae582db2867)
This commit is contained in:
MengYX 2021-12-18 21:35:22 +08:00
parent 632651b371
commit 8ce76fa7dc
1 changed files with 11 additions and 4 deletions
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15
src/decrypt/qmc.ts
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@ -177,16 +177,14 @@ export class QmcDecoder {
this.audioSize = this.size - keySize - 8 this.audioSize = this.size - keySize - 8
const rawKey = this.file.subarray(this.audioSize, this.size - 8) const rawKey = this.file.subarray(this.audioSize, this.size - 8)
const keyEnd = rawKey.findIndex(v => v == QmcDecoder.BYTE_COMMA) const keyEnd = rawKey.findIndex(v => v == QmcDecoder.BYTE_COMMA)
const keyDec = QmcDeriveKey(rawKey.subarray(0, keyEnd)) this.setCipher(rawKey.subarray(0, keyEnd))
this.cipher = new QmcRC4Cipher(keyDec)
} else { } else {
const sizeView = new DataView(last4Byte.buffer, last4Byte.byteOffset); const sizeView = new DataView(last4Byte.buffer, last4Byte.byteOffset);
const keySize = sizeView.getUint32(0, true) const keySize = sizeView.getUint32(0, true)
if (keySize < 0x300) { if (keySize < 0x300) {
this.audioSize = this.size - keySize - 4 this.audioSize = this.size - keySize - 4
const rawKey = this.file.subarray(this.audioSize, this.size - 4) const rawKey = this.file.subarray(this.audioSize, this.size - 4)
const keyDec = QmcDeriveKey(rawKey) this.setCipher(rawKey)
this.cipher = new QmcMapCipher(keyDec)
} else { } else {
this.audioSize = this.size this.audioSize = this.size
this.cipher = new QmcStaticCipher() this.cipher = new QmcStaticCipher()
@ -194,5 +192,14 @@ export class QmcDecoder {
} }
} }
private setCipher(keyRaw: Uint8Array) {
const keyDec = QmcDeriveKey(keyRaw)
if (keyDec.length > 300) {
this.cipher = new QmcRC4Cipher(keyDec)
} else {
this.cipher = new QmcMapCipher(keyDec)
}
}
} }