diff --git a/client/src/crypto/native.rs b/client/src/crypto/native.rs index 16642f31..f8220584 100644 --- a/client/src/crypto/native.rs +++ b/client/src/crypto/native.rs @@ -86,6 +86,16 @@ pub(crate) fn generate_public_key(private_key: impl AsRef<[u8]>) -> Result, +) -> Result, super::Error> { + let private_key_uint = BigUint::from_bytes_be(private_key.as_ref()); + static DH_GENERATOR: LazyLock = LazyLock::new(|| BigUint::from_u64(0x2).unwrap()); + let public_key_uint = powm_for_secret_exchange(&DH_GENERATOR, private_key_uint); + + Ok(public_key_uint.to_bytes_be()) +} + pub(crate) fn generate_aes_key( private_key: impl AsRef<[u8]>, server_public_key: impl AsRef<[u8]>, @@ -115,6 +125,35 @@ pub(crate) fn generate_aes_key( Ok(okm) } +pub(crate) fn generate_aes_key_for_secret_exchange( + private_key: impl AsRef<[u8]>, + server_public_key: impl AsRef<[u8]>, +) -> Result>, super::Error> { + let server_public_key_uint = BigUint::from_bytes_be(server_public_key.as_ref()); + let private_key_uint = BigUint::from_bytes_be(private_key.as_ref()); + let common_secret = powm_for_secret_exchange(&server_public_key_uint, private_key_uint); + + let mut common_secret_bytes = common_secret.to_bytes_be(); + let mut common_secret_padded = vec![0; 192 - common_secret_bytes.len()]; + // inefficient, but ok for now + common_secret_padded.append(&mut common_secret_bytes); + + // hkdf + // input_keying_material + let ikm = common_secret_padded; + let salt = None; + let info = []; + + // output keying material + let mut okm = Zeroizing::new(vec![0; 16]); + + let (_, hk) = Hkdf::::extract(salt, &ikm); + hk.expand(&info, okm.as_mut()) + .expect("hkdf expand should never fail"); + + Ok(okm) +} + pub fn generate_iv() -> Result, super::Error> { Ok(EncAlg::generate_iv(cipher::rand_core::OsRng).to_vec()) } @@ -242,3 +281,39 @@ fn powm(base: &BigUint, mut exp: BigUint) -> BigUint { result } + +fn powm_for_secret_exchange(base: &BigUint, mut exp: BigUint) -> BigUint { + // for key exchange + static DH_PRIME: LazyLock = LazyLock::new(|| { + BigUint::from_bytes_be(&[ + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC9, 0x0F, 0xDA, 0xA2, 0x21, 0x68, + 0xC2, 0x34, 0xC4, 0xC6, 0x62, 0x8B, 0x80, 0xDC, 0x1C, 0xD1, 0x29, 0x02, 0x4E, 0x08, + 0x8A, 0x67, 0xCC, 0x74, 0x02, 0x0B, 0xBE, 0xA6, 0x3B, 0x13, 0x9B, 0x22, 0x51, 0x4A, + 0x08, 0x79, 0x8E, 0x34, 0x04, 0xDD, 0xEF, 0x95, 0x19, 0xB3, 0xCD, 0x3A, 0x43, 0x1B, + 0x30, 0x2B, 0x0A, 0x6D, 0xF2, 0x5F, 0x14, 0x37, 0x4F, 0xE1, 0x35, 0x6D, 0x6D, 0x51, + 0xC2, 0x45, 0xE4, 0x85, 0xB5, 0x76, 0x62, 0x5E, 0x7E, 0xC6, 0xF4, 0x4C, 0x42, 0xE9, + 0xA6, 0x37, 0xED, 0x6B, 0x0B, 0xFF, 0x5C, 0xB6, 0xF4, 0x06, 0xB7, 0xED, 0xEE, 0x38, + 0x6B, 0xFB, 0x5A, 0x89, 0x9F, 0xA5, 0xAE, 0x9F, 0x24, 0x11, 0x7C, 0x4B, 0x1F, 0xE6, + 0x49, 0x28, 0x66, 0x51, 0xEC, 0xE4, 0x5B, 0x3D, 0xC2, 0x00, 0x7C, 0xB8, 0xA1, 0x63, + 0xBF, 0x05, 0x98, 0xDA, 0x48, 0x36, 0x1C, 0x55, 0xD3, 0x9A, 0x69, 0x16, 0x3F, 0xA8, + 0xFD, 0x24, 0xCF, 0x5F, 0x83, 0x65, 0x5D, 0x23, 0xDC, 0xA3, 0xAD, 0x96, 0x1C, 0x62, + 0xF3, 0x56, 0x20, 0x85, 0x52, 0xBB, 0x9E, 0xD5, 0x29, 0x07, 0x70, 0x96, 0x96, 0x6D, + 0x67, 0x0C, 0x35, 0x4E, 0x4A, 0xBC, 0x98, 0x04, 0xF1, 0x74, 0x6C, 0x08, 0xCA, 0x23, + 0x73, 0x27, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + ]) + }); + + let mut base = base.clone(); + let mut result: BigUint = One::one(); + + while !exp.is_zero() { + if exp.is_odd() { + result = result.mul(&base).rem(&*DH_PRIME); + } + exp = exp.shr(1); + base = (&base).mul(&base).rem(&*DH_PRIME); + } + exp.zeroize(); + + result +} diff --git a/client/src/crypto/openssl.rs b/client/src/crypto/openssl.rs index d59d188a..7077153d 100644 --- a/client/src/crypto/openssl.rs +++ b/client/src/crypto/openssl.rs @@ -98,6 +98,18 @@ pub(crate) fn generate_public_key(private_key: impl AsRef<[u8]>) -> Result, +) -> Result, super::Error> { + let private_key_bn = BigNum::from_slice(private_key.as_ref()).unwrap(); + let dh = Dh::from_pqg( + BigNum::get_rfc3526_prime_1536().unwrap(), + None, + BigNum::from_u32(2).unwrap(), + )?; + Ok(dh.set_private_key(private_key_bn)?.public_key().to_vec()) +} + pub(crate) fn generate_aes_key( private_key: impl AsRef<[u8]>, server_public_key: impl AsRef<[u8]>, @@ -131,6 +143,39 @@ pub(crate) fn generate_aes_key( Ok(okm) } +pub(crate) fn generate_aes_key_for_secret_exchange( + private_key: impl AsRef<[u8]>, + server_public_key: impl AsRef<[u8]>, +) -> Result>, super::Error> { + let private_key_bn = BigNum::from_slice(private_key.as_ref()).unwrap(); + let server_public_key_bn = BigNum::from_slice(server_public_key.as_ref()).unwrap(); + let dh = Dh::from_pqg( + BigNum::get_rfc2409_prime_1024().unwrap(), + None, + BigNum::from_u32(2).unwrap(), + )?; + let mut common_secret_bytes = dh + .set_private_key(private_key_bn)? + .compute_key(&server_public_key_bn)?; + + let mut common_secret_padded = vec![0; 192 - common_secret_bytes.len()]; + // inefficient, but ok for now + common_secret_padded.append(&mut common_secret_bytes); + + // hkdf + // input_keying_material + let ikm = common_secret_padded; + + let mut okm = Zeroizing::new(vec![0; 16]); + let mut ctx = PkeyCtx::new_id(Id::HKDF).unwrap(); + ctx.derive_init().unwrap(); + ctx.set_hkdf_md(Md::sha256()).unwrap(); + ctx.set_hkdf_key(&ikm).unwrap(); + ctx.derive(Some(okm.as_mut())) + .expect("hkdf expand should never fail"); + Ok(okm) +} + pub fn generate_iv() -> Result, super::Error> { let mut buf = vec![0; iv_len()]; rand_bytes(&mut buf)?; diff --git a/client/src/key.rs b/client/src/key.rs index 6baa92b0..02d045ec 100644 --- a/client/src/key.rs +++ b/client/src/key.rs @@ -47,6 +47,14 @@ impl Key { Ok(Self::new(crypto::generate_public_key(private_key)?)) } + pub fn generate_public_key_for_secret_exchange( + private_key: &Self, + ) -> Result { + Ok(Self::new(crypto::generate_public_key_for_secret_exchange( + private_key, + )?)) + } + pub fn generate_aes_key( private_key: &Self, server_public_key: &Self, @@ -55,6 +63,15 @@ impl Key { crypto::generate_aes_key(private_key, server_public_key)?.to_vec(), )) } + + pub fn generate_aes_key_for_secret_exchange( + private_key: &Self, + server_public_key: &Self, + ) -> Result { + Ok(Self::new( + crypto::generate_aes_key_for_secret_exchange(private_key, server_public_key)?.to_vec(), + )) + } } impl From<&Key> for zvariant::Value<'_> {