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use super::CryptoError;
use openssl::bn::BigNumContext;
use openssl::derive::Deriver;
use openssl::ec::{EcGroup, EcKey, PointConversionForm};
use openssl::error::ErrorStack;
use openssl::hash::{hash, MessageDigest};
use openssl::nid::Nid;
use openssl::pkey::{PKey, Private, Public};
use openssl::rand::rand_bytes;
use openssl::sign::Signer;
use openssl::symm::{Cipher, Crypter, Mode};
use std::os::raw::c_int;
#[cfg(test)]
use openssl::ec::EcPoint;
#[cfg(test)]
use openssl::bn::BigNum;
const AES_BLOCK_SIZE: usize = 16;
impl From<ErrorStack> for CryptoError {
fn from(e: ErrorStack) -> Self {
CryptoError::Backend(format!("{e}"))
}
}
impl From<&ErrorStack> for CryptoError {
fn from(e: &ErrorStack) -> Self {
CryptoError::Backend(format!("{e}"))
}
}
pub type Result<T> = std::result::Result<T, CryptoError>;
/// ECDH using OpenSSL types. Computes the x coordinate of scalar multiplication of `peer_public`
/// by `client_private`.
fn ecdh_openssl_raw(client_private: EcKey<Private>, peer_public: EcKey<Public>) -> Result<Vec<u8>> {
let client_pkey = PKey::from_ec_key(client_private)?;
let peer_pkey = PKey::from_ec_key(peer_public)?;
let mut deriver = Deriver::new(&client_pkey)?;
deriver.set_peer(&peer_pkey)?;
let shared_point = deriver.derive_to_vec()?;
Ok(shared_point)
}
/// Ephemeral ECDH over P256. Takes a DER SubjectPublicKeyInfo that encodes a public key. Generates
/// an ephemeral P256 key pair. Returns
/// 1) the x coordinate of the shared point, and
/// 2) the uncompressed SEC 1 encoding of the ephemeral public key.
pub fn ecdhe_p256_raw(peer_spki: &[u8]) -> Result<(Vec<u8>, Vec<u8>)> {
let peer_public = EcKey::public_key_from_der(peer_spki)?;
// Hard-coding the P256 group here is easier than extracting a group name from peer_public and
// comparing it with P256. We'll fail in key derivation if peer_public is on the wrong curve.
let group = EcGroup::from_curve_name(Nid::X9_62_PRIME256V1)?;
let mut bn_ctx = BigNumContext::new()?;
let client_private = EcKey::generate(&group)?;
let client_public_sec1 = client_private.public_key().to_bytes(
&group,
PointConversionForm::UNCOMPRESSED,
&mut bn_ctx,
)?;
let shared_point = ecdh_openssl_raw(client_private, peer_public)?;
Ok((shared_point, client_public_sec1))
}
/// AES-256-CBC encryption for data that is a multiple of the AES block size (16 bytes) in length.
/// Uses the zero IV if `iv` is None.
pub fn encrypt_aes_256_cbc_no_pad(key: &[u8], iv: Option<&[u8]>, data: &[u8]) -> Result<Vec<u8>> {
let iv = iv.unwrap_or(&[0u8; AES_BLOCK_SIZE]);
let mut encrypter = Crypter::new(Cipher::aes_256_cbc(), Mode::Encrypt, key, Some(iv))?;
encrypter.pad(false);
let in_len = data.len();
if in_len % AES_BLOCK_SIZE != 0 {
return Err(CryptoError::LibraryFailure);
}
// OpenSSL would panic if we didn't allocate an extra block here.
let mut out = vec![0; in_len + AES_BLOCK_SIZE];
let mut out_len = 0;
out_len += encrypter.update(data, out.as_mut_slice())?;
out_len += encrypter.finalize(out.as_mut_slice())?;
debug_assert_eq!(in_len, out_len);
out.truncate(out_len);
Ok(out)
}
/// AES-256-CBC decryption for data that is a multiple of the AES block size (16 bytes) in length.
/// Uses the zero IV if `iv` is None.
pub fn decrypt_aes_256_cbc_no_pad(key: &[u8], iv: Option<&[u8]>, data: &[u8]) -> Result<Vec<u8>> {
let iv = iv.unwrap_or(&[0u8; AES_BLOCK_SIZE]);
let mut encrypter = Crypter::new(Cipher::aes_256_cbc(), Mode::Decrypt, key, Some(iv))?;
encrypter.pad(false);
let in_len = data.len();
if in_len % AES_BLOCK_SIZE != 0 {
return Err(CryptoError::LibraryFailure);
}
// OpenSSL would panic if we didn't allocate an extra block here.
let mut out = vec![0; in_len + AES_BLOCK_SIZE];
let mut out_len = 0;
out_len += encrypter.update(data, out.as_mut_slice())?;
out_len += encrypter.finalize(out.as_mut_slice())?;
debug_assert_eq!(in_len, out_len);
out.truncate(out_len);
Ok(out)
}
/// Textbook HMAC-SHA256
pub fn hmac_sha256(key: &[u8], data: &[u8]) -> Result<Vec<u8>> {
let key = PKey::hmac(key)?;
let mut signer = Signer::new(MessageDigest::sha256(), &key)?;
signer.update(data)?;
Ok(signer.sign_to_vec()?)
}
pub fn sha256(data: &[u8]) -> Result<Vec<u8>> {
let digest = hash(MessageDigest::sha256(), data)?;
Ok(digest.as_ref().to_vec())
}
pub fn random_bytes(count: usize) -> Result<Vec<u8>> {
if count > c_int::MAX as usize {
return Err(CryptoError::LibraryFailure);
}
let mut out = vec![0u8; count];
rand_bytes(&mut out)?;
Ok(out)
}
#[cfg(test)]
pub fn test_ecdh_p256_raw(
peer_spki: &[u8],
client_public_x: &[u8],
client_public_y: &[u8],
client_private: &[u8],
) -> Result<Vec<u8>> {
let peer_public = EcKey::public_key_from_der(peer_spki)?;
let group = peer_public.group();
let mut client_pub_sec1 = vec![];
client_pub_sec1.push(0x04); // SEC 1 encoded uncompressed point
client_pub_sec1.extend_from_slice(&client_public_x);
client_pub_sec1.extend_from_slice(&client_public_y);
let mut ctx = BigNumContext::new()?;
let client_pub_point = EcPoint::from_bytes(&group, &client_pub_sec1, &mut ctx)?;
let client_priv_bignum = BigNum::from_slice(client_private)?;
let client_private =
EcKey::from_private_components(&group, &client_priv_bignum, &client_pub_point)?;
let shared_point = ecdh_openssl_raw(client_private, peer_public)?;
Ok(shared_point)
}
pub fn gen_p256() -> Result<(Vec<u8>, Vec<u8>)> {
unimplemented!()
}
pub fn ecdsa_p256_sha256_sign_raw(_private: &[u8], _data: &[u8]) -> Result<Vec<u8>> {
unimplemented!()
}
#[allow(dead_code)]
#[cfg(test)]
pub fn test_ecdsa_p256_sha256_verify_raw(
_public: &[u8],
_signature: &[u8],
_data: &[u8],
) -> Result<()> {
unimplemented!()
}
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