move common msd functions + cleanup formats.rs + fix compiler warning in epk3

src/formats/msd.rs

@@ -0,0 +1,60 @@
+// COMMON MSD FUNCTIONS
+use aes::Aes128;
+use cbc::{Decryptor, cipher::{block_padding::Pkcs7, BlockDecryptMut, KeyIvInit}};
+
+type Aes128CbcDec = Decryptor<Aes128>;
+
+pub fn decrypt_aes_salted_old(encrypted_data: &[u8], passphrase_bytes: &Vec<u8>) -> Result<Vec<u8>, Box<dyn std::error::Error>> {
+    let mut data = encrypted_data.to_vec();
+
+    assert!(data[0..8].to_vec() == b"Salted__", "invalid encrypted data!");
+    let salt = &data[8..16];
+
+    //key = md5 of (passphrase + salt)
+    let mut key = Vec::new();
+    key.extend_from_slice(&passphrase_bytes);
+    key.extend_from_slice(&salt);
+    let key_md5 = md5::compute(&key);
+
+    //iv = md5 of (md5 of key + passphrase + salt)
+    let mut iv = Vec::new();
+    iv.extend_from_slice(&key_md5.0);
+    iv.extend_from_slice(&passphrase_bytes);
+    iv.extend_from_slice(&salt);
+    let iv_md5 = md5::compute(&iv);
+
+    let decryptor = Aes128CbcDec::new((&key_md5.0).into(), (&iv_md5.0).into());
+    let decrypted = decryptor.decrypt_padded_mut::<Pkcs7>(&mut data[16..])
+        .map_err(|e| format!("Decryption error!!: {:?}", e))?;
+    
+    Ok(decrypted.to_vec())
+}
+
+pub fn decrypt_aes_salted_tizen(encrypted_data: &[u8], passphrase_bytes: &Vec<u8>) -> Result<Vec<u8>, Box<dyn std::error::Error>> {
+    let mut data = encrypted_data.to_vec();
+
+    assert!(data[0..8].to_vec() == b"Salted__", "invalid encrypted data!");
+    let salt = &data[8..16];
+
+    //iv = md5 of salt
+    let iv = md5::compute(&salt);
+
+    let decryptor = Aes128CbcDec::new((&(**passphrase_bytes)).into(), (&iv.0).into());
+    let decrypted = decryptor.decrypt_padded_mut::<Pkcs7>(&mut data[16..])
+        .map_err(|e| format!("Decryption error!!: {:?}", e))?;
+    
+    Ok(decrypted.to_vec())
+}
+
+pub fn decrypt_aes_tizen(encrypted_data: &[u8], passphrase_bytes: &Vec<u8>, salt: &[u8]) -> Result<Vec<u8>, Box<dyn std::error::Error>> {
+    let mut data = encrypted_data.to_vec();
+
+    //iv = md5 of salt
+    let iv = md5::compute(&salt);
+
+    let decryptor = Aes128CbcDec::new((&(**passphrase_bytes)).into(), (&iv.0).into());
+    let decrypted = decryptor.decrypt_padded_mut::<Pkcs7>(&mut data)
+        .map_err(|e| format!("Decryption error!!: {:?}", e))?;
+    
+    Ok(decrypted.to_vec())
+}