diff options
author | Igor Matuszewski <igor@sequoia-pgp.org> | 2020-04-10 00:03:01 +0200 |
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committer | Igor Matuszewski <igor@sequoia-pgp.org> | 2020-06-22 11:57:06 +0200 |
commit | df5eb44e8e442c5bc4d958d914121075258393ec (patch) | |
tree | f5106537792d08b7b33920aa5467f0dedae91121 /openpgp/src/crypto/backend | |
parent | baf6f108b94f7e7b3a2ec12396e9bfbbd67c76ee (diff) |
openpgp: Move Nettle asymmetric impls to the backend module
Diffstat (limited to 'openpgp/src/crypto/backend')
-rw-r--r-- | openpgp/src/crypto/backend/nettle.rs | 2 | ||||
-rw-r--r-- | openpgp/src/crypto/backend/nettle/asymmetric.rs | 352 |
2 files changed, 354 insertions, 0 deletions
diff --git a/openpgp/src/crypto/backend/nettle.rs b/openpgp/src/crypto/backend/nettle.rs index 5c0149fc..e7614445 100644 --- a/openpgp/src/crypto/backend/nettle.rs +++ b/openpgp/src/crypto/backend/nettle.rs @@ -2,6 +2,8 @@ use nettle::random::{Random, Yarrow}; +pub mod asymmetric; + /// Fills the given buffer with random data. pub fn random<B: AsMut<[u8]>>(mut buf: B) { Yarrow::default().random(buf.as_mut()); diff --git a/openpgp/src/crypto/backend/nettle/asymmetric.rs b/openpgp/src/crypto/backend/nettle/asymmetric.rs new file mode 100644 index 00000000..95c3c7e2 --- /dev/null +++ b/openpgp/src/crypto/backend/nettle/asymmetric.rs @@ -0,0 +1,352 @@ +//! Hold the implementation of [`Signer`] and [`Decryptor`] for [`KeyPair`]. +//! +//! [`Signer`]: ../../asymmetric/trait.Signer.html +//! [`Decryptor`]: ../../asymmetric/trait.Decryptor.html +//! [`KeyPair`]: ../../asymmetric/struct.KeyPair.html + +use nettle::{ecc, ecdsa, ed25519, dsa, rsa, random::Yarrow}; + +use crate::{Error, Result}; + +use crate::packet::{self, key, Key}; +use crate::crypto::asymmetric::{KeyPair, Decryptor, Signer}; +use crate::crypto::mpi::{self, MPI}; +use crate::crypto::SessionKey; +use crate::types::{Curve, HashAlgorithm}; + +impl Signer for KeyPair { + fn public(&self) -> &Key<key::PublicParts, key::UnspecifiedRole> { + KeyPair::public(self) + } + + fn sign(&mut self, hash_algo: HashAlgorithm, digest: &[u8]) + -> Result<mpi::Signature> + { + use crate::PublicKeyAlgorithm::*; + use crate::crypto::mpi::PublicKey; + + let mut rng = Yarrow::default(); + + self.secret().map(|secret| { + #[allow(deprecated)] + match (self.public().pk_algo(), self.public().mpis(), secret) + { + (RSASign, + &PublicKey::RSA { ref e, ref n }, + &mpi::SecretKeyMaterial::RSA { ref p, ref q, ref d, .. }) | + (RSAEncryptSign, + &PublicKey::RSA { ref e, ref n }, + &mpi::SecretKeyMaterial::RSA { ref p, ref q, ref d, .. }) => { + let public = rsa::PublicKey::new(n.value(), e.value())?; + let secret = rsa::PrivateKey::new(d.value(), p.value(), + q.value(), Option::None)?; + + // The signature has the length of the modulus. + let mut sig = vec![0u8; n.value().len()]; + + // As described in [Section 5.2.2 and 5.2.3 of RFC 4880], + // to verify the signature, we need to encode the + // signature data in a PKCS1-v1.5 packet. + // + // [Section 5.2.2 and 5.2.3 of RFC 4880]: + // https://tools.ietf.org/html/rfc4880#section-5.2.2 + rsa::sign_digest_pkcs1(&public, &secret, digest, + hash_algo.oid()?, + &mut rng, &mut sig)?; + + Ok(mpi::Signature::RSA { + s: MPI::new(&sig), + }) + }, + + (DSA, + &PublicKey::DSA { ref p, ref q, ref g, .. }, + &mpi::SecretKeyMaterial::DSA { ref x }) => { + let params = dsa::Params::new(p.value(), q.value(), g.value()); + let secret = dsa::PrivateKey::new(x.value()); + + let sig = dsa::sign(¶ms, &secret, digest, &mut rng)?; + + Ok(mpi::Signature::DSA { + r: MPI::new(&sig.r()), + s: MPI::new(&sig.s()), + }) + }, + + (EdDSA, + &PublicKey::EdDSA { ref curve, ref q }, + &mpi::SecretKeyMaterial::EdDSA { ref scalar }) => match curve { + Curve::Ed25519 => { + let public = q.decode_point(&Curve::Ed25519)?.0; + + let mut sig = vec![0; ed25519::ED25519_SIGNATURE_SIZE]; + + // Nettle expects the private key to be exactly + // ED25519_KEY_SIZE bytes long but OpenPGP allows leading + // zeros to be stripped. + // Padding has to be unconditional; otherwise we have a + // secret-dependent branch. + let missing = ed25519::ED25519_KEY_SIZE + .saturating_sub(scalar.value().len()); + let mut sec = [0u8; ed25519::ED25519_KEY_SIZE]; + sec[missing..].copy_from_slice(scalar.value()); + + let res = ed25519::sign(public, &sec[..], digest, &mut sig); + unsafe { + memsec::memzero(sec.as_mut_ptr(), + ed25519::ED25519_KEY_SIZE); + } + res?; + + Ok(mpi::Signature::EdDSA { + r: MPI::new(&sig[..32]), + s: MPI::new(&sig[32..]), + }) + }, + _ => Err( + Error::UnsupportedEllipticCurve(curve.clone()).into()), + }, + + (ECDSA, + &PublicKey::ECDSA { ref curve, .. }, + &mpi::SecretKeyMaterial::ECDSA { ref scalar }) => { + let secret = match curve { + Curve::NistP256 => + ecc::Scalar::new::<ecc::Secp256r1>( + scalar.value())?, + Curve::NistP384 => + ecc::Scalar::new::<ecc::Secp384r1>( + scalar.value())?, + Curve::NistP521 => + ecc::Scalar::new::<ecc::Secp521r1>( + scalar.value())?, + _ => + return Err( + Error::UnsupportedEllipticCurve(curve.clone()) + .into()), + }; + + let sig = ecdsa::sign(&secret, digest, &mut rng); + + Ok(mpi::Signature::ECDSA { + r: MPI::new(&sig.r()), + s: MPI::new(&sig.s()), + }) + }, + + (pk_algo, _, _) => Err(Error::InvalidOperation(format!( + "unsupported combination of algorithm {:?}, key {:?}, \ + and secret key {:?}", + pk_algo, self.public(), self.secret())).into()), + }}) + } +} + +impl Decryptor for KeyPair { + fn public(&self) -> &Key<key::PublicParts, key::UnspecifiedRole> { + KeyPair::public(self) + } + + /// Creates a signature over the `digest` produced by `hash_algo`. + fn decrypt(&mut self, ciphertext: &mpi::Ciphertext, + plaintext_len: Option<usize>) + -> Result<SessionKey> + { + use crate::PublicKeyAlgorithm::*; + use crate::crypto::mpi::PublicKey; + + self.secret().map( + |secret| Ok(match (self.public().mpis(), secret, ciphertext) + { + (PublicKey::RSA{ ref e, ref n }, + mpi::SecretKeyMaterial::RSA{ ref p, ref q, ref d, .. }, + mpi::Ciphertext::RSA{ ref c }) => { + // Workaround for #440: Make sure c is of the same + // length as n. + // XXX: Remove once we depend on nettle > 7.0.0. + let c_ = if c.value().len() < n.value().len() { + let mut c_ = vec![0; n.value().len() - c.value().len()]; + c_.extend_from_slice(c.value()); + Some(c_) + } else { + // If it is bigger, then the packet is likely + // corrupted, tough luck then. + None + }; + let c = if let Some(c_) = c_.as_ref() { + &c_[..] + } else { + c.value() + }; + // End of workaround. + + let public = rsa::PublicKey::new(n.value(), e.value())?; + let secret = rsa::PrivateKey::new(d.value(), p.value(), + q.value(), Option::None)?; + let mut rand = Yarrow::default(); + if let Some(l) = plaintext_len { + let mut plaintext: SessionKey = vec![0; l].into(); + rsa::decrypt_pkcs1(&public, &secret, &mut rand, + c, plaintext.as_mut())?; + plaintext + } else { + rsa::decrypt_pkcs1_insecure(&public, &secret, + &mut rand, c)? + .into() + } + } + + (PublicKey::ElGamal{ .. }, + mpi::SecretKeyMaterial::ElGamal{ .. }, + mpi::Ciphertext::ElGamal{ .. }) => + return Err( + Error::UnsupportedPublicKeyAlgorithm(ElGamalEncrypt).into()), + + (PublicKey::ECDH{ .. }, + mpi::SecretKeyMaterial::ECDH { .. }, + mpi::Ciphertext::ECDH { .. }) => + crate::crypto::ecdh::decrypt(self.public(), secret, ciphertext)?, + + (public, secret, ciphertext) => + return Err(Error::InvalidOperation(format!( + "unsupported combination of key pair {:?}/{:?} \ + and ciphertext {:?}", + public, secret, ciphertext)).into()), + })) + } +} + + +impl<P: key::KeyParts, R: key::KeyRole> Key<P, R> { + /// Encrypts the given data with this key. + pub fn encrypt(&self, data: &SessionKey) -> Result<mpi::Ciphertext> { + use crate::PublicKeyAlgorithm::*; + + #[allow(deprecated)] + match self.pk_algo() { + RSAEncryptSign | RSAEncrypt => { + // Extract the public recipient. + match self.mpis() { + mpi::PublicKey::RSA { e, n } => { + // The ciphertext has the length of the modulus. + let mut esk = vec![0u8; n.value().len()]; + let mut rng = Yarrow::default(); + let pk = rsa::PublicKey::new(n.value(), e.value())?; + rsa::encrypt_pkcs1(&pk, &mut rng, data, + &mut esk)?; + Ok(mpi::Ciphertext::RSA { + c: MPI::new(&esk), + }) + }, + pk => { + Err(Error::MalformedPacket( + format!( + "Key: Expected RSA public key, got {:?}", + pk)).into()) + }, + } + }, + ECDH => crate::crypto::ecdh::encrypt(self.parts_as_public(), + data), + algo => Err(Error::UnsupportedPublicKeyAlgorithm(algo).into()), + } + } + + /// Verifies the given signature. + pub fn verify(&self, sig: &packet::Signature, digest: &[u8]) -> Result<()> + { + use crate::PublicKeyAlgorithm::*; + use crate::crypto::mpi::{PublicKey, Signature}; + + #[allow(deprecated)] + let ok = match (sig.pk_algo(), self.mpis(), sig.mpis()) { + (RSASign, PublicKey::RSA { e, n }, Signature::RSA { s }) | + (RSAEncryptSign, PublicKey::RSA { e, n }, Signature::RSA { s }) => { + let key = rsa::PublicKey::new(n.value(), e.value())?; + + // As described in [Section 5.2.2 and 5.2.3 of RFC 4880], + // to verify the signature, we need to encode the + // signature data in a PKCS1-v1.5 packet. + // + // [Section 5.2.2 and 5.2.3 of RFC 4880]: + // https://tools.ietf.org/html/rfc4880#section-5.2.2 + rsa::verify_digest_pkcs1(&key, digest, sig.hash_algo().oid()?, + s.value())? + }, + (DSA, PublicKey::DSA{ y, p, q, g }, Signature::DSA { s, r }) => { + let key = dsa::PublicKey::new(y.value()); + let params = dsa::Params::new(p.value(), q.value(), g.value()); + let signature = dsa::Signature::new(r.value(), s.value()); + + dsa::verify(¶ms, &key, digest, &signature) + }, + (EdDSA, PublicKey::EdDSA{ curve, q }, Signature::EdDSA { r, s }) => + match curve { + Curve::Ed25519 => { + if q.value().get(0).map(|&b| b != 0x40).unwrap_or(true) { + return Err(Error::MalformedPacket( + "Invalid point encoding".into()).into()); + } + + // OpenPGP encodes R and S separately, but our + // cryptographic library expects them to be + // concatenated. + let mut signature = + Vec::with_capacity(ed25519::ED25519_SIGNATURE_SIZE); + + // We need to zero-pad them at the front, because + // the MPI encoding drops leading zero bytes. + let half = ed25519::ED25519_SIGNATURE_SIZE / 2; + if r.value().len() < half { + for _ in 0..half - r.value().len() { + signature.push(0); + } + } + signature.extend_from_slice(r.value()); + if s.value().len() < half { + for _ in 0..half - s.value().len() { + signature.push(0); + } + } + signature.extend_from_slice(s.value()); + + // Let's see if we got it right. + if signature.len() != ed25519::ED25519_SIGNATURE_SIZE { + return Err(Error::MalformedPacket( + format!( + "Invalid signature size: {}, r: {:?}, s: {:?}", + signature.len(), r.value(), s.value())).into()); + } + + ed25519::verify(&q.value()[1..], digest, &signature)? + }, + _ => return + Err(Error::UnsupportedEllipticCurve(curve.clone()).into()), + }, + (ECDSA, PublicKey::ECDSA{ curve, q }, Signature::ECDSA { s, r }) => + { + let (x, y) = q.decode_point(curve)?; + let key = match curve { + Curve::NistP256 => ecc::Point::new::<ecc::Secp256r1>(x, y)?, + Curve::NistP384 => ecc::Point::new::<ecc::Secp384r1>(x, y)?, + Curve::NistP521 => ecc::Point::new::<ecc::Secp521r1>(x, y)?, + _ => return Err( + Error::UnsupportedEllipticCurve(curve.clone()).into()), + }; + + let signature = dsa::Signature::new(r.value(), s.value()); + ecdsa::verify(&key, digest, &signature) + }, + _ => return Err(Error::MalformedPacket(format!( + "unsupported combination of algorithm {}, key {} and \ + signature {:?}.", + sig.pk_algo(), self.pk_algo(), sig.mpis())).into()), + }; + + if ok { + Ok(()) + } else { + Err(Error::ManipulatedMessage.into()) + } + } +} |