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Consolidate agreement functions into LcPtr<EVP_PKEY> #854

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Consolidate agreement functions into LcPtr<EVP_PKEY> #854

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109 changes: 20 additions & 89 deletions aws-lc-rs/src/agreement.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -65,9 +65,8 @@ use crate::hex;
pub use ephemeral::{agree_ephemeral, EphemeralPrivateKey};

use crate::aws_lc::{
EVP_PKEY_derive, EVP_PKEY_derive_init, EVP_PKEY_derive_set_peer, EVP_PKEY_get0_EC_KEY,
NID_X9_62_prime256v1, NID_secp384r1, NID_secp521r1, EVP_PKEY, EVP_PKEY_EC, EVP_PKEY_X25519,
NID_X25519,
i2d_ECPrivateKey, EVP_PKEY_get0_EC_KEY, NID_X9_62_prime256v1, NID_secp384r1, NID_secp521r1,
EVP_PKEY, EVP_PKEY_EC, EVP_PKEY_X25519, NID_X25519,
};

use crate::buffer::Buffer;
Expand All @@ -78,7 +77,6 @@ use crate::encoding::{
EcPublicKeyCompressedBin, EcPublicKeyUncompressedBin, Pkcs8V1Der, PublicKeyX509Der,
};
use crate::evp_pkey::No_EVP_PKEY_CTX_consumer;
use crate::fips::indicator_check;
use crate::pkcs8::Version;
use crate::ptr::LcPtr;
use core::fmt;
Expand Down Expand Up @@ -455,7 +453,7 @@ impl AsDer<EcPrivateKeyRfc5915Der<'static>> for PrivateKey {
|evp_pkey| EVP_PKEY_get0_EC_KEY(*evp_pkey.as_const())
})?
};
let length = usize::try_from(unsafe { aws_lc::i2d_ECPrivateKey(*ec_key, &mut outp) })
let length = usize::try_from(unsafe { i2d_ECPrivateKey(*ec_key, &mut outp) })
.map_err(|_| Unspecified)?;
let mut outp = LcPtr::new(outp)?;
Ok(EcPrivateKeyRfc5915Der::take_from_slice(unsafe {
Expand Down Expand Up @@ -712,107 +710,40 @@ where

let peer_pub_bytes = peer_public_key.bytes.as_ref();

let mut buffer = [0u8; MAX_AGREEMENT_SECRET_LEN];

let secret: &[u8] = match &my_private_key.inner_key {
KeyInner::X25519(priv_key) => {
x25519_diffie_hellman(&mut buffer, priv_key, peer_pub_bytes).or(Err(error_value))?
}
KeyInner::ECDH_P256(priv_key)
| KeyInner::ECDH_P384(priv_key)
| KeyInner::ECDH_P521(priv_key) => {
ec_key_ecdh(&mut buffer, priv_key, peer_pub_bytes, expected_nid).or(Err(error_value))?
let parse_result = match &my_private_key.inner_key {
KeyInner::X25519(_) => try_parse_x25519_public_key_bytes(peer_pub_bytes),
KeyInner::ECDH_P256(_) | KeyInner::ECDH_P384(_) | KeyInner::ECDH_P521(_) => {
encoding::parse_ec_public_key(peer_pub_bytes, expected_nid)
}
};
kdf(secret)
}

// Current max secret length is P-521's.
const MAX_AGREEMENT_SECRET_LEN: usize = AlgorithmID::ECDH_P521.private_key_len();

#[inline]
#[allow(clippy::needless_pass_by_value)]
fn ec_key_ecdh<'a>(
buffer: &'a mut [u8; MAX_AGREEMENT_SECRET_LEN],
priv_key: &LcPtr<EVP_PKEY>,
peer_pub_key_bytes: &[u8],
nid: i32,
) -> Result<&'a [u8], Unspecified> {
let mut pub_key = encoding::parse_ec_public_key(peer_pub_key_bytes, nid)?;

let mut pkey_ctx = priv_key.create_EVP_PKEY_CTX()?;

if 1 != unsafe { EVP_PKEY_derive_init(*pkey_ctx.as_mut()) } {
return Err(Unspecified);
}

if 1 != unsafe { EVP_PKEY_derive_set_peer(*pkey_ctx.as_mut(), *pub_key.as_mut()) } {
return Err(Unspecified);
}

let mut out_key_len = buffer.len();

if 1 != indicator_check!(unsafe {
EVP_PKEY_derive(*pkey_ctx.as_mut(), buffer.as_mut_ptr(), &mut out_key_len)
}) {
return Err(Unspecified);
}

if 0 == out_key_len {
return Err(Unspecified);
}

Ok(&buffer[0..out_key_len])
}

#[inline]
fn x25519_diffie_hellman<'a>(
buffer: &'a mut [u8; MAX_AGREEMENT_SECRET_LEN],
priv_key: &LcPtr<EVP_PKEY>,
peer_pub_key: &[u8],
) -> Result<&'a [u8], ()> {
let mut pkey_ctx = priv_key.create_EVP_PKEY_CTX()?;

if 1 != unsafe { EVP_PKEY_derive_init(*pkey_ctx.as_mut()) } {
return Err(());
}
if let Ok(peer_pub_key) = parse_result {
let secret = my_private_key
.inner_key
.get_evp_pkey()
.agree(&peer_pub_key)
.or(Err(error_value))?;

let mut pub_key = try_parse_x25519_public_key_bytes(peer_pub_key)?;

if 1 != unsafe { EVP_PKEY_derive_set_peer(*pkey_ctx.as_mut(), *pub_key.as_mut()) } {
return Err(());
}

let mut out_key_len = buffer.len();

if 1 != indicator_check!(unsafe {
EVP_PKEY_derive(*pkey_ctx.as_mut(), buffer.as_mut_ptr(), &mut out_key_len)
}) {
return Err(());
kdf(secret.as_ref())
} else {
Err(error_value)
}

debug_assert!(out_key_len == AlgorithmID::X25519.pub_key_len());

Ok(&buffer[0..AlgorithmID::X25519.pub_key_len()])
}

pub(crate) fn try_parse_x25519_public_key_bytes(
key_bytes: &[u8],
) -> Result<LcPtr<EVP_PKEY>, Unspecified> {
) -> Result<LcPtr<EVP_PKEY>, KeyRejected> {
LcPtr::<EVP_PKEY>::parse_rfc5280_public_key(key_bytes, EVP_PKEY_X25519)
.or(try_parse_x25519_public_key_raw_bytes(key_bytes))
}

fn try_parse_x25519_public_key_raw_bytes(key_bytes: &[u8]) -> Result<LcPtr<EVP_PKEY>, Unspecified> {
fn try_parse_x25519_public_key_raw_bytes(key_bytes: &[u8]) -> Result<LcPtr<EVP_PKEY>, KeyRejected> {
let expected_pub_key_len = X25519.id.pub_key_len();
if key_bytes.len() != expected_pub_key_len {
return Err(Unspecified);
return Err(KeyRejected::invalid_encoding());
}

Ok(LcPtr::<EVP_PKEY>::parse_raw_public_key(
key_bytes,
EVP_PKEY_X25519,
)?)
LcPtr::<EVP_PKEY>::parse_raw_public_key(key_bytes, EVP_PKEY_X25519)
}

#[cfg(test)]
Expand Down
30 changes: 29 additions & 1 deletion aws-lc-rs/src/evp_pkey.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,8 @@

use crate::aws_lc::{
EVP_DigestSign, EVP_DigestSignInit, EVP_DigestVerify, EVP_DigestVerifyInit, EVP_PKEY_CTX_new,
EVP_PKEY_CTX_new_id, EVP_PKEY_bits, EVP_PKEY_cmp, EVP_PKEY_get0_EC_KEY, EVP_PKEY_get0_RSA,
EVP_PKEY_CTX_new_id, EVP_PKEY_bits, EVP_PKEY_cmp, EVP_PKEY_derive, EVP_PKEY_derive_init,
EVP_PKEY_derive_set_peer, EVP_PKEY_get0_EC_KEY, EVP_PKEY_get0_RSA,
EVP_PKEY_get_raw_private_key, EVP_PKEY_get_raw_public_key, EVP_PKEY_id, EVP_PKEY_keygen,
EVP_PKEY_keygen_init, EVP_PKEY_new_raw_private_key, EVP_PKEY_new_raw_public_key, EVP_PKEY_sign,
EVP_PKEY_sign_init, EVP_PKEY_size, EVP_PKEY_up_ref, EVP_PKEY_verify, EVP_PKEY_verify_init,
Expand Down Expand Up @@ -489,6 +490,33 @@ impl LcPtr<EVP_PKEY> {
}
}

pub(crate) fn agree(&self, peer_key: &Self) -> Result<Box<[u8]>, Unspecified> {
let mut pctx = self.create_EVP_PKEY_CTX()?;

if 1 != unsafe { EVP_PKEY_derive_init(*pctx.as_mut()) } {
return Err(Unspecified);
}

let mut secret_len = 0;
if 1 != unsafe { EVP_PKEY_derive_set_peer(*pctx.as_mut(), *peer_key.as_mut_unsafe()) } {
return Err(Unspecified);
}

if 1 != unsafe { EVP_PKEY_derive(*pctx.as_mut(), null_mut(), &mut secret_len) } {
return Err(Unspecified);
}

let mut secret = vec![0u8; secret_len];
if 1 != indicator_check!(unsafe {
EVP_PKEY_derive(*pctx.as_mut(), secret.as_mut_ptr(), &mut secret_len)
}) {
return Err(Unspecified);
}
secret.truncate(secret_len);

Ok(secret.into_boxed_slice())
}

pub(crate) fn generate<F>(pkey_type: c_int, params_fn: Option<F>) -> Result<Self, Unspecified>
where
F: EVP_PKEY_CTX_consumer,
Expand Down
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