Improved encryption implementation

src/netmd/encryption.rs

@@ -9,11 +9,26 @@ use super::interface::DataEncryptorInput;
 type DesEcbEnc = ecb::Decryptor<des::Des>;
 type DesCbcEnc = cbc::Encryptor<des::Des>;
 
-pub fn new_thread_encryptor(
-    _input: DataEncryptorInput,
-) -> UnboundedReceiver<(Vec<u8>, Vec<u8>, Vec<u8>)> {
+pub struct Encryptor {
+    channel: Option<UnboundedReceiver<(Vec<u8>, Vec<u8>, Vec<u8>)>>,
+    state: Option<EncryptorState>,
+}
+
+struct EncryptorState {
+    input_data: Vec<u8>,
+    iv: [u8; 8],
+    random_key: [u8; 8],
+    encrypted_random_key: [u8; 8],
+    default_chunk_size: usize,
+    current_chunk_size: usize,
+    offset: usize,
+    packet_count: usize,
+    closed: bool,
+}
+
+impl Encryptor {
+    pub fn new_threaded(input: DataEncryptorInput) -> Self {
         let (tx, rx) = unbounded_channel::<(Vec<u8>, Vec<u8>, Vec<u8>)>();
-    let input = Box::from(_input);
 
         thread::spawn(move || {
             let mut iv = [0u8; 8];
@@ -74,5 +89,108 @@ pub fn new_thread_encryptor(
             }
         });
 
-    rx
+        Self {
+            channel: Some(rx),
+            state: None
+        }
+    }
+
+    pub fn new(input: DataEncryptorInput) -> Self {
+        let iv = [0u8; 8];
+
+        // Create the random key
+        let mut random_key = [0u8; 8];
+        rand::thread_rng().fill_bytes(&mut random_key);
+
+        // Encrypt it with the kek
+        let mut encrypted_random_key = random_key;
+        if let Err(x) = DesEcbEnc::new(&input.kek.into())
+            .decrypt_padded_mut::<NoPadding>(&mut encrypted_random_key)
+        {
+            panic!("Cannot create main key {:?}", x)
+        };
+
+        let default_chunk_size = match input.chunk_size {
+            0 => 0x00100000,
+            e => e,
+        };
+
+        let packet_count = 0;
+        let current_chunk_size = 0;
+
+        let mut input_data = input.data.clone();
+        if (input_data.len() % input.frame_size) != 0 {
+            let padding_remaining = input.frame_size - (input_data.len() % input.frame_size);
+            input_data.extend(std::iter::repeat(0).take(padding_remaining));
+        }
+
+        let offset: usize = 0;
+
+        Encryptor {
+            channel: None,
+            state: Some(EncryptorState {
+                input_data,
+                iv,
+                random_key,
+                encrypted_random_key,
+                current_chunk_size,
+                offset,
+                default_chunk_size,
+                packet_count,
+                closed: false,
+            })
+        }
+    }
+
+    /// Get the next encrypted value
+    pub async fn next(&mut self) -> Option<(Vec<u8>, Vec<u8>, Vec<u8>)> {
+        let output;
+
+        if let Some(state) = self.state.as_mut() {
+            if state.closed {
+                return None
+            }
+
+            if state.packet_count > 0 {
+                state.current_chunk_size = state.default_chunk_size;
+            } else {
+                state.current_chunk_size = state.default_chunk_size - 24;
+            }
+
+            state.current_chunk_size = std::cmp::min(state.current_chunk_size, state.input_data.len() - state.offset);
+
+            let this_data_chunk = &mut state.input_data[state.offset..state.offset + state.current_chunk_size];
+            DesCbcEnc::new(&state.random_key.into(), &state.iv.into())
+                .encrypt_padded_mut::<NoPadding>(this_data_chunk, state.current_chunk_size)
+                .unwrap();
+
+            output = Some((
+                state.encrypted_random_key.to_vec(),
+                state.iv.to_vec(),
+                this_data_chunk.to_vec(),
+            ));
+
+            state.iv.copy_from_slice(&this_data_chunk[this_data_chunk.len() - 8..]);
+
+            state.packet_count += 1;
+            state.offset += state.current_chunk_size;
+        } else if let Some(channel) = self.channel.as_mut() {
+            output = channel.recv().await
+        } else {
+            unreachable!("If you got here, this is bad!");
+        }
+
+        output
+    }
+
+    /// Call close to return none from subsequent calls
+    pub fn close(&mut self) {
+        if let Some(state) = self.state.as_mut() {
+            state.closed = true;
+        } else if let Some(channel) = self.channel.as_mut() {
+            channel.close()
+        } else {
+            unreachable!("If you got here, this is bad!");
+        }
+    }
 }

src/netmd/interface.rs

@@ -15,9 +15,9 @@ use std::collections::HashMap;
 use std::error::Error;
 use std::time::Duration;
 use thiserror::Error;
-use tokio::sync::mpsc::UnboundedReceiver;
 
 use super::base::NetMD;
+use super::encryption::Encryptor;
 use super::utils::{cross_sleep, to_sjis};
 
 /// An action to take on the player
@@ -1690,8 +1690,7 @@ impl NetMDInterface {
         discformat: u8,
         frames: u32,
         pkt_size: u32,
-        // key, iv, data
-        mut packets: UnboundedReceiver<(Vec<u8>, Vec<u8>, Vec<u8>)>,
+        mut packets: Encryptor,
         hex_session_key: &[u8],
         progress_callback: F,
     ) -> Result<(u16, Vec<u8>, Vec<u8>), InterfaceError>
@@ -1730,7 +1729,7 @@ impl NetMDInterface {
         let mut written_bytes = 0;
         let mut packet_count = 0;
 
-        while let Some((key, iv, data)) = packets.recv().await {
+        while let Some((key, iv, data)) = packets.next().await {
             let binpack = if packet_count == 0 {
                 let packed_length: Vec<u8> = pkt_size.to_be_bytes().to_vec();
                 [vec![0, 0, 0, 0], packed_length, key, iv, data].concat()
@@ -1863,10 +1862,6 @@ pub struct MDTrack {
     pub data: Vec<u8>,
     pub chunk_size: usize,
     pub full_width_title: Option<String>,
-
-    #[allow(clippy::type_complexity)]
-    pub encrypt_packets_iterator:
-        Box<dyn Fn(DataEncryptorInput) -> UnboundedReceiver<(Vec<u8>, Vec<u8>, Vec<u8>)>>,
 }
 
 pub struct DataEncryptorInput {
@@ -1921,8 +1916,19 @@ impl MDTrack {
         [0x14, 0xe3, 0x83, 0x4e, 0xe2, 0xd3, 0xcc, 0xa5]
     }
 
-    pub fn get_encrypting_iterator(&mut self) -> UnboundedReceiver<(Vec<u8>, Vec<u8>, Vec<u8>)> {
-        (self.encrypt_packets_iterator)(DataEncryptorInput {
+    #[cfg(not(target_family = "wasm"))]
+    pub fn get_encrypting_iterator(&mut self) -> Encryptor {
+        Encryptor::new_threaded(DataEncryptorInput {
+            kek: self.get_kek(),
+            frame_size: self.frame_size(),
+            chunk_size: self.chunk_size(),
+            data: std::mem::take(&mut self.data),
+        })
+    }
+
+    #[cfg(target_family = "wasm")]
+    pub fn get_encrypting_iterator(&mut self) -> Encryptor {
+        Encryptor::new(DataEncryptorInput {
             kek: self.get_kek(),
             frame_size: self.frame_size(),
             chunk_size: self.chunk_size(),