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[kgm] feat: add decipher self-test on startup

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This commit is contained in:
鲁树人 2024-09-15 23:53:00 +01:00
parent da806d7ad4
commit 92a52c1565
2 changed files with 42 additions and 0 deletions
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36
um_crypto/kgm/src/header.rs
View File

@ -11,6 +11,8 @@ pub struct Header {
pub key_slot: u32,
pub decrypt_test_data: [u8; 0x10],
pub file_key: [u8; 0x10],
challenge_data: [u8; 0x10],
}
impl Header {
@ -25,6 +27,8 @@ impl Header {
let mut magic = [0u8; 0x10];
magic.copy_from_slice(&buffer[..0x10]);
let challenge_data = get_challenge_data(&magic)?;
let offset_to_data = LE::read_u32(&buffer[0x10..0x14]) as usize;
let crypto_version = LE::read_u32(&buffer[0x14..0x18]);
let key_slot = LE::read_u32(&buffer[0x18..0x1C]);
@ -40,6 +44,7 @@ impl Header {
key_slot,
decrypt_test_data,
file_key,
challenge_data,
})
}
@ -54,6 +59,37 @@ impl Header {
3 => Box::from(DecipherV3::new(self, slot_key)?),
version => Err(KugouError::UnsupportedCipherVersion(version))?,
};
let mut test_data = self.decrypt_test_data;
decipher.decrypt(&mut test_data, 0);
if self.challenge_data != test_data {
Err(KugouError::SelfTestFailed)?;
}
Ok(decipher)
}
}
fn get_challenge_data(magic_header: &[u8; 0x10]) -> Result<[u8; 0x10], KugouError> {
match magic_header {
&KGM_HEADER => Ok(KGM_TEST_DATA),
&VPR_HEADER => Ok(VPR_TEST_DATA),
_ => Err(KugouError::NotKGMFile)?,
}
}
pub const KGM_HEADER: [u8; 16] = [
0x7C, 0xD5, 0x32, 0xEB, 0x86, 0x02, 0x7F, 0x4B, 0xA8, 0xAF, 0xA6, 0x8E, 0x0F, 0xFF, 0x99, 0x14,
];
pub const KGM_TEST_DATA: [u8; 16] = [
0x38, 0x85, 0xED, 0x92, 0x79, 0x5F, 0xF8, 0x4C, 0xB3, 0x03, 0x61, 0x41, 0x16, 0xA0, 0x1D, 0x47,
];
pub const VPR_HEADER: [u8; 16] = [
0x05, 0x28, 0xBC, 0x96, 0xE9, 0xE4, 0x5A, 0x43, 0x91, 0xAA, 0xBD, 0xD0, 0x7A, 0xF5, 0x36, 0x31,
];
pub const VPR_TEST_DATA: [u8; 16] = [
0x1D, 0x5A, 0x05, 0x34, 0x0C, 0x41, 0x8D, 0x42, 0x9C, 0x83, 0x92, 0x6C, 0xAE, 0x16, 0xFE, 0x56,
];

6
um_crypto/kgm/src/lib.rs
View File

@ -14,6 +14,12 @@ pub enum KugouError {
#[error("Unsupported cipher version: {0}")]
UnsupportedCipherVersion(u32),
#[error("Not KGM File (magic mismatch)")]
NotKGMFile,
#[error("Unsupported cipher (self-test failed)")]
SelfTestFailed,
}
pub trait Decipher {