feat: add kgm v5 (kgg) support.

um_crypto/kgm/src/lib.rs

@@ -2,6 +2,7 @@ pub mod header;
 mod pc_db_decrypt;
 pub mod v2;
 pub mod v3;
+mod v5;
 
 pub use pc_db_decrypt::decrypt_db;
 
@@ -10,6 +11,7 @@ use crate::v2::DecipherV2;
 use crate::v3::DecipherV3;
 use thiserror::Error;
 
+use crate::v5::DecipherV5;
 use block_padding::UnpadError;
 
 #[derive(Debug, Error)]
@@ -18,11 +20,14 @@ pub enum KugouError {
     HeaderTooSmall(usize),
 
     #[error("Unsupported key slot: {0}")]
-    UnsupportedKeySlot(u32),
+    UnsupportedKeySlot(i32),
 
     #[error("Unsupported cipher version: {0}")]
     UnsupportedCipherVersion(u32),
 
+    #[error("V5 requires ekey.")]
+    V5EKeyRequired,
+
     #[error("Not KGM File (magic mismatch)")]
     NotKGMFile,
 
@@ -40,23 +45,42 @@ pub enum KugouError {
 
     #[error("Database does not seem valid")]
     InvalidPage1Header,
+
+    #[error("QMC2EKeyError: {0}")]
+    QMC2EKeyError(String),
+
+    #[error("Parse KGM header with i/o error: {0}")]
+    HeaderParseIOError(std::io::Error),
+
+    #[error("Invalid audio hash size: {0}")]
+    HeaderInvalidAudioHash(usize),
 }
 
 pub enum Decipher {
     V2(DecipherV2),
     V3(DecipherV3),
+    V5(DecipherV5),
 }
 
 impl Decipher {
     pub fn new(header: &Header) -> Result<Self, KugouError> {
+        Self::new_v5(header, None)
+    }
+
+    pub fn new_v5(header: &Header, ekey: Option<String>) -> Result<Self, KugouError> {
         let slot_key: &[u8] = match header.key_slot {
             1 => b"l,/'",
+            -1 => b"", // unused, kgm v5 (kgg)
             slot => Err(KugouError::UnsupportedKeySlot(slot))?,
         };
 
         let decipher = match header.crypto_version {
             2 => Decipher::V2(DecipherV2::new(header, slot_key)?),
             3 => Decipher::V3(DecipherV3::new(header, slot_key)?),
+            5 => match ekey {
+                Some(ekey) => Decipher::V5(DecipherV5::new(&ekey)?),
+                _ => Err(KugouError::V5EKeyRequired)?,
+            },
             version => Err(KugouError::UnsupportedCipherVersion(version))?,
         };
 
@@ -73,6 +97,7 @@ impl Decipher {
         match self {
             Decipher::V2(decipher) => decipher.decrypt(buffer, offset),
             Decipher::V3(decipher) => decipher.decrypt(buffer, offset),
+            Decipher::V5(decipher) => decipher.decrypt(buffer, offset),
         }
     }
 }