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use crate::api::*;
// use crate::config::*;
use crate::error::Error;
use crate::service::*;
use crate::types::*;
// TODO: The non-detached versions seem better.
// This needs a bit of additional type gymnastics.
// Maybe start a discussion on the `aead` crate's GitHub about usability concerns...
#[cfg(feature = "chacha8-poly1305")]
impl GenerateKey for super::Chacha8Poly1305 {
#[inline(never)]
fn generate_key(keystore: &mut impl Keystore, request: &request::GenerateKey)
-> Result<reply::GenerateKey, Error>
{
use rand_core::RngCore as _;
// 32 bytes entropy
// 12 bytes nonce
let mut serialized = [0u8; 44];
let entropy = &mut serialized[..32];
keystore.rng().fill_bytes(entropy);
// store keys
let key_id = keystore.store_key(
request.attributes.persistence,
key::Secrecy::Secret,
key::Kind::Symmetric32Nonce(12),
&serialized,
)?;
Ok(reply::GenerateKey { key: key_id })
}
}
#[inline(never)]
fn increment_nonce(nonce: &mut [u8]) -> Result<(), Error> {
let mut carry: u16 = 1;
for digit in nonce.iter_mut() {
let x = (*digit as u16) + carry;
*digit = x as u8;
carry = x >> 8;
}
if carry == 0 {
Ok(())
} else {
Err(Error::NonceOverflow)
}
}
#[cfg(feature = "chacha8-poly1305")]
impl Decrypt for super::Chacha8Poly1305
{
#[inline(never)]
fn decrypt(keystore: &mut impl Keystore, request: &request::Decrypt)
-> Result<reply::Decrypt, Error>
{
use chacha20poly1305::ChaCha8Poly1305;
use chacha20poly1305::aead::{AeadInPlace, NewAead};
let serialized_material = keystore
.load_key(key::Secrecy::Secret, Some(key::Kind::Symmetric32Nonce(12)), &request.key)?
.material;
let serialized = serialized_material.as_slice();
// if serialized.len() != 44 {
// return Error::InternalError;
// }
assert!(serialized.len() == 44);
let symmetric_key = &serialized[..32];
let aead = ChaCha8Poly1305::new(&GenericArray::clone_from_slice(&symmetric_key));
let mut plaintext = request.message.clone();
let nonce = GenericArray::from_slice(&request.nonce);
let tag = GenericArray::from_slice(&request.tag);
let outcome = aead.decrypt_in_place_detached(
&nonce, &request.associated_data, &mut plaintext, &tag);
// outcome.map_err(|_| Error::AeadError)?;
Ok(reply::Decrypt { plaintext: {
if outcome.is_ok() {
Some(plaintext)
} else {
None
}
}})
}
}
#[cfg(feature = "chacha8-poly1305")]
impl Encrypt for super::Chacha8Poly1305
{
#[inline(never)]
fn encrypt(keystore: &mut impl Keystore, request: &request::Encrypt)
-> Result<reply::Encrypt, Error>
{
use chacha20poly1305::ChaCha8Poly1305;
use chacha20poly1305::aead::{AeadInPlace, NewAead};
// load key and nonce
let secrecy = key::Secrecy::Secret;
let key_kind = key::Kind::Symmetric32Nonce(12);
let key_id = &request.key;
let mut serialized_material = keystore
.load_key(secrecy, Some(key_kind), key_id)?
.material;
let serialized: &mut [u8] = serialized_material.as_mut();
assert!(serialized.len() == 44);
// no panic by above early return
let location = keystore.location(secrecy, key_id).unwrap();
// let key_id = request.key;
// let path = keystore.prepare_path_for_key(key::Secrecy::Secret, &key_id)?;
// let mut serialized = [0u8; 44];
// debug!("loading encryption key: {:?}", &path);
{
let nonce = &mut serialized[32..];
// increment nonce
increment_nonce(nonce)?;
}
// increment_nonce(&mut serialized[32..])?;
keystore.overwrite_key(location, secrecy, key_kind, key_id, &serialized)?;
let (symmetric_key, generated_nonce) = serialized.split_at_mut(32);
let nonce = match request.nonce.as_ref() {
Some(nonce) => nonce.as_ref(),
None => generated_nonce,
};
// keep in state?
let aead = ChaCha8Poly1305::new(&GenericArray::clone_from_slice(symmetric_key));
let mut ciphertext = request.message.clone();
let tag: [u8; 16] = aead.encrypt_in_place_detached(
&GenericArray::clone_from_slice(nonce),
&request.associated_data,
&mut ciphertext,
).unwrap().as_slice().try_into().unwrap();
let nonce = ShortData::from_slice(nonce).unwrap();
let tag = ShortData::from_slice(&tag).unwrap();
// let ciphertext = Message::from_slice(&ciphertext).unwrap();
Ok(reply::Encrypt { ciphertext, nonce, tag })
}
}
#[cfg(feature = "chacha8-poly1305")]
impl WrapKey for super::Chacha8Poly1305
{
#[inline(never)]
fn wrap_key(keystore: &mut impl Keystore, request: &request::WrapKey)
-> Result<reply::WrapKey, Error>
{
debug!("trussed: Chacha8Poly1305::WrapKey");
// TODO: need to check both secret and private keys
let serialized_key = keystore
.load_key(key::Secrecy::Secret, None, &request.key)?;
let message = Message::from_slice(&serialized_key.serialize()).unwrap();
let encryption_request = request::Encrypt {
mechanism: Mechanism::Chacha8Poly1305,
key: request.wrapping_key,
message,
associated_data: ShortData::new(),
nonce: None,
};
let encryption_reply = <super::Chacha8Poly1305>::encrypt(keystore, &encryption_request)?;
let wrapped_key = crate::postcard_serialize_bytes(&encryption_reply).map_err(|_| Error::CborError)?;
Ok(reply::WrapKey { wrapped_key })
}
}
#[cfg(feature = "chacha8-poly1305")]
impl UnwrapKey for super::Chacha8Poly1305
{
#[inline(never)]
fn unwrap_key(keystore: &mut impl Keystore, request: &request::UnwrapKey)
-> Result<reply::UnwrapKey, Error>
{
let reply::Encrypt { ciphertext, nonce, tag } = crate::postcard_deserialize(
&request.wrapped_key).map_err(|_| Error::CborError)?;
let decryption_request = request::Decrypt {
mechanism: Mechanism::Chacha8Poly1305,
key: request.wrapping_key,
message: ciphertext,
associated_data: request.associated_data.clone(),
nonce,
tag,
};
let serialized_key = if let Some(serialized_key) =
<super::Chacha8Poly1305>::decrypt(keystore, &decryption_request)?.plaintext {
serialized_key
} else {
return Ok(reply::UnwrapKey { key: None } );
};
// TODO: probably change this to returning Option<key> too
let key::Key{ flags: _, kind, material } = key::Key::try_deserialize(&serialized_key)?;
// TODO: need to check both secret and private keys
let key_id = keystore.store_key(
request.attributes.persistence,
// using for signing keys... we need to know
key::Secrecy::Secret,
kind,
&material,
)?;
Ok(reply::UnwrapKey { key: Some(key_id) })
}
}
// // // global choice of algorithm: we do Chacha8Poly1305 here
// // // TODO: oh how annoying these GenericArrays
// // pub fn aead_in_place(&mut self, ad: &[u8], buf: &mut [u8]) -> Result<(AeadNonce, AeadTag), Error> {
// // use chacha20poly1305::aead::{Aead, NewAead};
// // // keep in state?
// // let aead = ChaCha8Poly1305::new(GenericArray::clone_from_slice(&self.get_aead_key()?));
// // // auto-increments
// // let nonce = self.get_aead_nonce()?;
// // // aead.encrypt_in_place_detached(&nonce, ad, buf).map(|g| g.as_slice().try_into().unwrap())?;
// // // not sure what can go wrong with AEAD
// // let tag: AeadTag = aead.encrypt_in_place_detached(
// // &GenericArray::clone_from_slice(&nonce), ad, buf
// // ).unwrap().as_slice().try_into().unwrap();
// // Ok((nonce, tag))
// // }
// // pub fn adad_in_place(&mut self, nonce: &AeadNonce, ad: &[u8], buf: &mut [u8], tag: &AeadTag) -> Result<(), Error> {
// // use chacha20poly1305::aead::{Aead, NewAead};
// // // keep in state?
// // let aead = ChaCha8Poly1305::new(GenericArray::clone_from_slice(&self.get_aead_key()?));
// // aead.decrypt_in_place_detached(
// // &GenericArray::clone_from_slice(nonce),
// // ad,
// // buf,
// // &GenericArray::clone_from_slice(tag)
// // ).map_err(|_| Error::AeadError)
// // }
// #[cfg(feature = "chacha8-poly1305")]
// impl<P: Platform>
// Decrypt<P> for super::Chacha8Poly1305
// {
// fn decrypt(keystore: &mut impl Keystore, request: request::Decrypt)
// -> Result<reply::Decrypt, Error>
// {
// use block_modes::{BlockMode, Cbc};
// // use block_modes::Cbc;
// use block_modes::block_padding::ZeroPadding;
// use aes::Aes256;
// // TODO: perhaps use NoPadding and have client pad, to emphasize spec-conformance?
// type Aes256Cbc = Cbc<Aes256, ZeroPadding>;
// let key_id = request.key;
// let mut symmetric_key = [0u8; 32];
// let path = keystore.prepare_path_for_key(key::Secrecy::Secret, &key_id)?;
// keystore.load_serialized_key(&path, key::Kind::SymmetricKey32, &mut symmetric_key)?;
// let zero_iv = [0u8; 32];
// let cipher = Aes256Cbc::new_var(&symmetric_key, &zero_iv).unwrap();
// // buffer must have enough space for message+padding
// let mut buffer = request.message.clone();
// // // copy message to the buffer
// // let pos = plaintext.len();
// // buffer[..pos].copy_from_slice(plaintext);
// let l = buffer.len();
// // Decrypt message in-place.
// // Returns an error if buffer length is not multiple of block size and
// // if after decoding message has malformed padding.
// let plaintext = cipher.decrypt(&mut buffer).unwrap();
// let plaintext = Message::from_slice(&plaintext).unwrap();
// Ok(reply::Decrypt { plaintext: Ok(plaintext) })
// }
// }
// // TODO: key a `/root/aead-nonce` counter (or use entropy?)
// // TODO: how do we want to organize this? probably the key itself should have an associated nonce,
// // so using a key actually modifies its state!
// pub fn get_aead_nonce() -> Result<AeadNonce, Error> {
// Ok([42u8; 12])
// }
// impl<P: Platform>
// Encrypt<P> for super::Chacha8Poly1305
// {
// fn encrypt(keystore: &mut impl Keystore, request: request::Encrypt)
// -> Result<reply::Encrypt, Error>
// {
// use chacha20poly1305::ChaCha8Poly1305;
// let key_id = request.key;
// let path = keystore.prepare_path_for_key(key::Secrecy::Secret, &key_id)?;
// let mut symmetric_key = [0u8; 32];
// keystore.load_serialized_key(&path, key::Kind::SymmetricKey32, &mut symmetric_key)?;
// // keep in state?
// let aead = ChaCha8Poly1305::new(GenericArray::clone_from_slice(&symmetric_key)?);
// // auto-increments
// let nonce: [u8; 12] = get_aead_nonce()?;
// let tag: AeadTag = aead.encrypt_in_place_detached(
// &GenericArray::clone_from_slice(&nonce), ad, buf
// ).unwrap().as_slice().try_into().unwrap();
// Ok((nonce, tag))
// // // buffer must have enough space for message+padding
// // let mut buffer = request.message.clone();
// // // // copy message to the buffer
// // // let pos = plaintext.len();
// // // buffer[..pos].copy_from_slice(plaintext);
// // let l = buffer.len();
// // // Encrypt message in-place.
// // // &buffer[..pos] is used as a message and &buffer[pos..] as a reserved space for padding.
// // // The padding space should be big enough for padding, otherwise method will return Err(BlockModeError).
// // let ciphertext = cipher.encrypt(&mut buffer, l).unwrap();
// // let ciphertext = Message::from_slice(&ciphertext).unwrap();
// Ok(reply::Encrypt { ciphertext })
// }
// }
// // // global choice of algorithm: we do Chacha8Poly1305 here
// // // TODO: oh how annoying these GenericArrays
// // pub fn aead_in_place(&mut self, ad: &[u8], buf: &mut [u8]) -> Result<(AeadNonce, AeadTag), Error> {
// // use chacha20poly1305::aead::{Aead, NewAead};
// // // keep in state?
// // let aead = ChaCha8Poly1305::new(GenericArray::clone_from_slice(&self.get_aead_key()?));
// // // auto-increments
// // let nonce = self.get_aead_nonce()?;
// // // aead.encrypt_in_place_detached(&nonce, ad, buf).map(|g| g.as_slice().try_into().unwrap())?;
// // // not sure what can go wrong with AEAD
// // let tag: AeadTag = aead.encrypt_in_place_detached(
// // &GenericArray::clone_from_slice(&nonce), ad, buf
// // ).unwrap().as_slice().try_into().unwrap();
// // Ok((nonce, tag))
// // }
// // pub fn adad_in_place(&mut self, nonce: &AeadNonce, ad: &[u8], buf: &mut [u8], tag: &AeadTag) -> Result<(), Error> {
// // use chacha20poly1305::aead::{Aead, NewAead};
// // // keep in state?
// // let aead = ChaCha8Poly1305::new(GenericArray::clone_from_slice(&self.get_aead_key()?));
// // aead.decrypt_in_place_detached(
// // &GenericArray::clone_from_slice(nonce),
// // ad,
// // buf,
// // &GenericArray::clone_from_slice(tag)
// // ).map_err(|_| Error::AeadError)
// // }
#[cfg(not(feature = "chacha8-poly1305"))]
impl<P: Platform>
Decrypt<P> for super::Chacha8Poly1305 {}
#[cfg(not(feature = "chacha8-poly1305"))]
impl<P: Platform>
Encrypt<P> for super::Chacha8Poly1305 {}
#[cfg(not(feature = "chacha8-poly1305"))]
impl<P: Platform>
GenerateKey<P> for super::Chacha8Poly1305 {}