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// SPDX-FileCopyrightText: 2021-2024 Wiktor Kwapisiewicz <wiktor@metacode.biz>
// SPDX-FileCopyrightText: 2022-2024 Heiko Schaefer <heiko@schaefer.name>
// SPDX-License-Identifier: MIT OR Apache-2.0
use openpgp_card::ocard::algorithm::{AlgorithmAttributes, Curve};
use openpgp_card::ocard::crypto::{EccType, PublicKeyMaterial};
use ssh_agent_lib::proto::SignRequest;
use ssh_key::public::EcdsaPublicKey;
use ssh_key::public::Ed25519PublicKey;
use ssh_key::public::KeyData;
use ssh_key::public::RsaPublicKey;
use ssh_key::sec1::EncodedPoint;
use ssh_key::Mpint;
pub(crate) fn get_ssh_pubkey(
pkm: &PublicKeyMaterial,
) -> Result<KeyData, Box<dyn std::error::Error>> {
match pkm {
PublicKeyMaterial::R(rsa) => {
let e = Mpint::from_positive_bytes(rsa.v())?;
let n = Mpint::from_positive_bytes(rsa.n())?;
Ok(KeyData::Rsa(RsaPublicKey { e, n }))
}
PublicKeyMaterial::E(ecc) => {
if let AlgorithmAttributes::Ecc(ecc_attrs) = ecc.algo() {
match ecc_attrs.ecc_type() {
EccType::EdDSA => {
let key = ecc.data().to_vec();
Ok(KeyData::Ed25519(Ed25519PublicKey(
key.try_into().map_err(|_e| anyhow::anyhow!("bad length"))?,
)))
}
EccType::ECDSA => {
if let AlgorithmAttributes::Ecc(ecc_attrs) = ecc.algo() {
Ok(KeyData::Ecdsa(match ecc_attrs.curve() {
Curve::NistP256r1 => {
EcdsaPublicKey::NistP256(EncodedPoint::from_bytes(ecc.data())?)
}
Curve::NistP384r1 => {
EcdsaPublicKey::NistP384(EncodedPoint::from_bytes(ecc.data())?)
}
Curve::NistP521r1 => {
EcdsaPublicKey::NistP521(EncodedPoint::from_bytes(ecc.data())?)
}
_ => {
return Err(anyhow::anyhow!(
"Unsupported ECDSA curve {:?}",
ecc_attrs.curve()
)
.into())
}
}))
} else {
Err(anyhow::anyhow!("Unexpected ecc.algo {:?}", ecc.algo()).into())
}
}
_ => {
Err(anyhow::anyhow!("Unexpected EccType {:?}", ecc_attrs.ecc_type()).into())
}
}
} else {
Err(anyhow::anyhow!("Unexpected Algo in EccPub {:?}", ecc).into())
}
}
}
}
pub(crate) fn signature_request_information(
request: &SignRequest,
pkm: &PublicKeyMaterial,
) -> Option<(ssh_key::Algorithm, Vec<u8>)> {
use sha2::Digest;
// Signature scheme "rsa-sha2-256" or "rsa-sha2-512" [I-D.ietf-curdle-rsa-sha2]
const SSH_AGENT_RSA_SHA2_256: u32 = 2;
const SSH_AGENT_RSA_SHA2_512: u32 = 4;
match pkm {
PublicKeyMaterial::R(_) => {
if request.flags & SSH_AGENT_RSA_SHA2_256 != 0 {
let mut hasher = sha2::Sha256::new();
hasher.update(&request.data);
Some((
ssh_key::Algorithm::Rsa {
hash: Some(ssh_key::HashAlg::Sha256),
},
hasher.finalize().to_vec(),
))
} else if request.flags & SSH_AGENT_RSA_SHA2_512 != 0 {
let mut hasher = sha2::Sha512::new();
hasher.update(&request.data);
Some((
ssh_key::Algorithm::Rsa {
hash: Some(ssh_key::HashAlg::Sha512),
},
hasher.finalize().to_vec(),
))
} else {
log::error!("Unexpected RSA case");
None
}
}
PublicKeyMaterial::E(ecc) => {
log::trace!("ECC data {:x?}, len {}", request.data, request.data.len());
if let AlgorithmAttributes::Ecc(ea) = ecc.algo() {
match ea.ecc_type() {
EccType::ECDSA => {
let curve = ea.curve();
log::trace!("ECDSA {:?}", curve);
match curve {
Curve::NistP256r1 => {
let mut hasher = sha2::Sha256::new();
hasher.update(&request.data);
let digest = hasher.finalize().to_vec();
Some((
ssh_key::Algorithm::Ecdsa {
curve: ssh_key::EcdsaCurve::NistP256,
},
digest,
))
}
Curve::NistP384r1 => {
let mut hasher = sha2::Sha384::new();
hasher.update(&request.data);
let digest = hasher.finalize().to_vec();
Some((
ssh_key::Algorithm::Ecdsa {
curve: ssh_key::EcdsaCurve::NistP384,
},
digest,
))
}
Curve::NistP521r1 => {
let mut hasher = sha2::Sha512::new();
hasher.update(&request.data);
let digest = hasher.finalize().to_vec();
Some((
ssh_key::Algorithm::Ecdsa {
curve: ssh_key::EcdsaCurve::NistP521,
},
digest,
))
}
_ => {
log::error!("Unexpected ECDSA curve {:?}", curve);
None
}
}
}
EccType::EdDSA => {
let curve = ea.curve();
assert_eq!(curve, &Curve::Ed25519);
// raw message to be hashed and signed, ed25519
Some((ssh_key::Algorithm::Ed25519, request.data.clone()))
}
e => {
log::error!("Unexpected EccType {:?}", e);
None
}
}
} else {
log::error!("Unexpected ECC case");
None
}
}
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_v_leading_zero_not_influencing_key_equality() {
let v = [1, 0, 1];
let n = [1, 2, 3, 4];
let e = Mpint::from_positive_bytes(&v).expect("v");
let n = Mpint::from_positive_bytes(&n).expect("n");
let first_key = KeyData::Rsa(RsaPublicKey { e, n });
// additional zero in "v"/"e" should not affect the result
let v = [0, 1, 0, 1];
let n = [1, 2, 3, 4];
let e = Mpint::from_positive_bytes(&v).expect("v");
let n = Mpint::from_positive_bytes(&n).expect("n");
let second_key = KeyData::Rsa(RsaPublicKey { e, n });
assert_eq!(first_key, second_key);
}
}