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mtk_pkg: fix decryption of unaligned data

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theubusu
2026-01-06 18:08:17 +01:00
parent 37eef68793
commit 24839ea9ab
2 changed files with 34 additions and 19 deletions
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src/formats/mtk_pkg.rs
+25 -17
View File
@@ -92,9 +92,7 @@ pub fn extract_mtk_pkg(mut file: &File, output_folder: &str) -> Result<(), Box<d
while file.stream_position()? < file_size as u64 {
part_n += 1;
let part_entry: PartEntry = file.read_le()?;
if !part_entry.is_valid() {
break
}
if !part_entry.is_valid() {break};
println!("\n#{} - {}, Size: {}{} {}",
part_n, part_entry.name(), part_entry.size, if part_entry.is_compressed() {" [COMPRESSED]"} else {""}, if part_entry.is_encrypted() {"[ENCRYPTED]"} else {""} );
@@ -106,7 +104,8 @@ pub fn extract_mtk_pkg(mut file: &File, output_folder: &str) -> Result<(), Box<d
continue
}
let mut out_data = Vec::new();
let mut matching_key: Option<[u8; 16]> = None;
let mut matching_iv: Option<[u8; 16]> = None;
if part_entry.is_encrypted() {
let crypted_header = &data[..48];
@@ -116,33 +115,42 @@ pub fn extract_mtk_pkg(mut file: &File, output_folder: &str) -> Result<(), Box<d
key[i * 4..(i + 1) * 4].copy_from_slice(&hdr.vendor_magic_bytes);
}
let try_decrypt = decrypt_aes128_cbc_nopad(&crypted_header, &key, &HEADER_IV)?;
if try_decrypt.starts_with(b"reserved mtk inc") {
println!("- Decrypting with 4xVendor magic...");
out_data = decrypt_aes128_cbc_nopad(&data[..data.len() & !15], &key, &HEADER_IV)?;
} else {
matching_key = Some(key);
matching_iv = Some(HEADER_IV);
} else {
//try decrypting with one of custom keys
let mut decrypted = false;
for (key_hex, iv_hex, name) in keys::MTK_PKG_CUST {
let key_array: [u8; 16] = hex::decode(key_hex)?.as_slice().try_into()?;
let iv_array: [u8; 16] = hex::decode(iv_hex)?.as_slice().try_into()?;
let try_decrypt = decrypt_aes128_cbc_nopad(&crypted_header, &key_array, &iv_array)?;
if try_decrypt.starts_with(b"reserved mtk inc") {
if try_decrypt.starts_with(b"reserved mtk inc") {
println!("- Decrypting with key {}...", name);
out_data = decrypt_aes128_cbc_nopad(&data[..data.len() & !15], &key_array, &iv_array)?;
decrypted = true;
matching_key = Some(key_array);
matching_iv = Some(iv_array);
break
}
}
}
}
let mut out_data;
if matching_key.is_some() && matching_iv.is_some() {
let (key_array, iv_array) = (matching_key.unwrap(), matching_iv.unwrap());
//data aligned to 16 bytes is AES encrypted. the remaining unaligned data is XORed with the key
let align_len = data.len() & !15;
let (aes_enc, xor_tail) = data.split_at(align_len);
out_data = decrypt_aes128_cbc_nopad(aes_enc, &key_array, &iv_array)?;
for (i, &b) in xor_tail.iter().enumerate() {
out_data.push(b ^ key_array[i % key_array.len()]);
}
if !decrypted {
println!("- Failed to decrypt data!");
continue
}
};
} else {
out_data = data;
println!("- Failed to decrypt data!");
continue
}
//strip iMtK thing and get version
src/formats/mtk_pkg_new.rs
+9 -2
View File
@@ -117,10 +117,17 @@ pub fn extract_mtk_pkg_new(mut file: &File, output_folder: &str) -> Result<(), B
continue
}
let out_data;
let mut out_data;
if part_entry.is_encrypted() {
println!("- Decrypting...");
out_data = decrypt_aes128_cbc_nopad(&data[..data.len() & !15], &matching_key.unwrap(), &matching_iv.unwrap())?;
let (key_array, iv_array) = (matching_key.unwrap(), matching_iv.unwrap());
//data aligned to 16 bytes is AES encrypted. the remaining unaligned data is XORed with the key
let align_len = data.len() & !15;
let (aes_enc, xor_tail) = data.split_at(align_len);
out_data = decrypt_aes128_cbc_nopad(aes_enc, &key_array, &iv_array)?;
for (i, &b) in xor_tail.iter().enumerate() {
out_data.push(b ^ key_array[i % key_array.len()]);
}
} else {
out_data = data;
}