[wasm] fix: decode ekey before decryption

um_crypto/qmc/src/lib.rs

@@ -29,7 +29,7 @@ impl QMCv2Cipher {
         let key = key.as_ref();
         let cipher = match key.len() {
             0 => Err(QmcCryptoError::QMCV2MapKeyEmpty)?,
-            ..=300 => QMCv2Cipher::MapL(QMC2Map::new(key)?),
+            1..=300 => QMCv2Cipher::MapL(QMC2Map::new(key)?),
             _ => QMCv2Cipher::RC4(QMC2RC4::new(key)),
         };
         Ok(cipher)

um_crypto/qmc/src/v2_rc4/cipher.rs

@@ -11,14 +11,14 @@ const RC4_STREAM_CACHE_SIZE: usize = OTHER_SEGMENT_SIZE + 512;
 pub struct QMC2RC4 {
     hash: f64,
     key: Box<[u8]>,
-    key_stream: [u8; RC4_STREAM_CACHE_SIZE],
+    key_stream: Box<[u8; RC4_STREAM_CACHE_SIZE]>,
 }
 
 impl QMC2RC4 {
     pub fn new(key: &[u8]) -> Self {
         let mut rc4 = RC4::new(key);
-        let mut key_stream = [0u8; RC4_STREAM_CACHE_SIZE];
+        let mut key_stream = Box::new([0u8; RC4_STREAM_CACHE_SIZE]);
-        rc4.derive(&mut key_stream);
+        rc4.derive(&mut key_stream[..]);
 
         Self {
             hash: hash(key),
@@ -31,8 +31,9 @@ impl QMC2RC4 {
         let n = self.key.len();
 
         for (datum, offset) in data.iter_mut().zip(offset..) {
-            let idx = get_segment_key(offset as u64, self.key[offset % n], self.hash) as usize;
+            let idx = get_segment_key(offset as u64, self.key[offset % n], self.hash);
-            *datum ^= self.key[idx % n];
+            let idx = idx % (n as u64);
+            *datum ^= self.key[idx as usize];
         }
     }
 
@@ -43,10 +44,11 @@ impl QMC2RC4 {
         let block_offset = offset % OTHER_SEGMENT_SIZE;
 
         let seed = self.key[id % n];
-        let skip = get_segment_key(id as u64, seed, self.hash) % 512;
+        let skip = get_segment_key(id as u64, seed, self.hash);
+        let skip = (skip & 0x1FF) as usize;
 
         debug_assert!(data.len() <= OTHER_SEGMENT_SIZE - block_offset);
-        let key_stream = self.key_stream.iter().skip(skip as usize + block_offset);
+        let key_stream = self.key_stream.iter().skip(skip + block_offset);
         for (datum, &key) in data.iter_mut().zip(key_stream) {
             *datum ^= key;
         }

um_crypto/qmc/src/v2_rc4/rc4.rs

@@ -42,8 +42,11 @@ impl RC4 {
         self.state[index]
     }
 
-    pub fn derive(&mut self, buffer: &mut [u8]) {
+    pub fn derive<T>(&mut self, buffer: &mut T)
-        for item in buffer.iter_mut() {
+    where
+        T: AsMut<[u8]> + ?Sized,
+    {
+        for item in buffer.as_mut().iter_mut() {
             *item ^= self.generate();
         }
     }

um_crypto/qmc/src/v2_rc4/segment_key.rs

@@ -1,9 +1,9 @@
-pub fn get_segment_key(id: u64, seed: u8, hash: f64) -> u32 {
+pub fn get_segment_key(id: u64, seed: u8, hash: f64) -> u64 {
     match seed {
         0 => 0,
         seed => {
             let result = hash / ((id + 1).wrapping_mul(seed.into()) as f64) * 100.0;
-            result as u32
+            result as u64
         }
     }
 }
@@ -21,4 +21,14 @@ mod tests {
     fn test_segment_key_123() {
         assert_eq!(get_segment_key(1, 123, 12345.0), 5018);
     }
+
+    #[test]
+    fn test_segment_key_large_1() {
+        assert_eq!(get_segment_key(51, 35, 516402887.0), 28373784);
+    }
+
+    #[test]
+    fn test_segment_key_large_2() {
+        assert_eq!(get_segment_key(0, 66, 3908240000.0), 5921575757);
+    }
 }

um_wasm/src/exports/qmc.rs

@@ -19,7 +19,8 @@ impl JsQMC2 {
     /// Create a new QMC2 (mgg/mflac) cipher instance.
     #[wasm_bindgen(constructor)]
     pub fn new(ekey: &str) -> Result<JsQMC2, JsError> {
-        let cipher = QMCv2Cipher::new(ekey.as_bytes()).map_err(map_js_error)?;
+        let key = umc_qmc::ekey::decrypt(ekey).map_err(map_js_error)?;
+        let cipher = QMCv2Cipher::new(key).map_err(map_js_error)?;
         Ok(JsQMC2(cipher))
     }
 

um_wasm_loader/build.js

@@ -62,7 +62,8 @@ async function main() {
   const wasmDistDir = path.resolve(__dirname, 'dist');
   await rm(wasmOutDir, { recursive: true, force: true });
   const wasmRelOutDir = path.relative(wasmSourceDir, wasmOutDir);
-  await run(['wasm-pack', 'build', '--target', 'web', '--out-dir', wasmRelOutDir], {
+  const profileFlag = process.env.BUILD_RELEASE ? '--release' : '--dev';
+  await run(['wasm-pack', 'build', profileFlag, '--target', 'web', '--out-dir', wasmRelOutDir], {
     cwd: path.resolve(__dirname, '..', 'um_wasm'),
   });
 

um_wasm_loader/src/loader.mjs

@@ -11,7 +11,7 @@ function loader() {
     const url = new URL('um_wasm_bg.wasm', import.meta.url);
     const wasm =
       url.protocol === 'file:'
-        ? import('node:f' + 's/promises')
+        ? import(/* @vite-ignore */ 'node:f' + 's/promises')
             .then((fs) => fs.readFile(url))
             .catch((err) => {
               console.log('read wasm failed', err);