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use std::{
borrow::Cow,
collections::HashMap,
fmt::{Debug, Display},
fs::{self, File},
io::{Read, Write},
path::{Path, PathBuf},
sync::Arc,
};
use bonsaidb_core::{
arc_bytes::serde::Bytes,
document::KeyId,
permissions::{
bonsai::{encryption_key_resource_name, EncryptionKeyAction},
Permissions,
},
};
use chacha20poly1305::{
aead::{generic_array::GenericArray, Aead, NewAead, Payload},
XChaCha20Poly1305,
};
use hpke::{
self,
aead::{AeadTag, ChaCha20Poly1305},
kdf::HkdfSha256,
kem::DhP256HkdfSha256,
Deserializable, Kem, OpModeS, Serializable,
};
use rand::{thread_rng, Rng};
use serde::{Deserialize, Serialize};
use zeroize::{Zeroize, Zeroizing};
#[derive(Serialize, Deserialize)]
pub enum KeyPair {
P256 {
private: <DhP256HkdfSha256 as Kem>::PrivateKey,
public: <DhP256HkdfSha256 as Kem>::PublicKey,
},
}
impl KeyPair {
pub fn to_bytes(&self) -> Result<Zeroizing<Vec<u8>>, Error> {
Ok(Zeroizing::new(bincode::serialize(self)?))
}
pub fn from_bytes(bytes: &[u8]) -> Result<Self, Error> {
bincode::deserialize(bytes).map_err(Error::from)
}
}
#[derive(Serialize, Deserialize)]
pub enum PublicKey {
P256(<DhP256HkdfSha256 as Kem>::PublicKey),
}
impl PublicKey {
pub fn to_bytes(&self) -> Result<Zeroizing<Vec<u8>>, Error> {
Ok(Zeroizing::new(bincode::serialize(self)?))
}
pub fn from_bytes(bytes: &[u8]) -> Result<Self, Error> {
bincode::deserialize(bytes).map_err(Error::from)
}
}
impl<'a> From<&'a KeyPair> for PublicKey {
fn from(key: &'a KeyPair) -> Self {
match key {
KeyPair::P256 { public, .. } => PublicKey::P256(public.clone()),
}
}
}
use crate::storage::StorageId;
pub(crate) struct Vault {
_vault_public_key: PublicKey,
master_keys: HashMap<u32, EncryptionKey>,
current_master_key_id: u32,
master_key_storage: Arc<dyn AnyVaultKeyStorage>,
}
impl Debug for Vault {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("Vault")
.field("master_keys", &self.master_keys)
.field("current_master_key_id", &self.current_master_key_id)
.field("master_key_storage", &self.master_key_storage)
.finish_non_exhaustive()
}
}
#[derive(thiserror::Error, Debug)]
pub enum Error {
#[error("error with encryption: {0}")]
Encryption(String),
#[error("error from vault key storage: {0}")]
VaultKeyStorage(String),
#[error("error occurred while initializing: {0}")]
Initializing(String),
#[error("vault key not found")]
VaultKeyNotFound,
}
impl From<chacha20poly1305::aead::Error> for Error {
fn from(err: chacha20poly1305::aead::Error) -> Self {
Self::Encryption(err.to_string())
}
}
impl From<hpke::HpkeError> for Error {
fn from(err: hpke::HpkeError) -> Self {
Self::Encryption(err.to_string())
}
}
impl From<bincode::Error> for Error {
fn from(err: bincode::Error) -> Self {
Self::Initializing(err.to_string())
}
}
impl Vault {
pub fn initialize(
server_id: StorageId,
server_directory: &Path,
master_key_storage: Arc<dyn AnyVaultKeyStorage>,
) -> Result<Self, Error> {
let master_keys_path = server_directory.join("master-keys");
if master_keys_path.exists() {
Self::unseal(&master_keys_path, server_id, master_key_storage)
} else {
Self::initialize_vault_key_storage(&master_keys_path, server_id, master_key_storage)
}
}
fn initialize_vault_key_storage(
master_keys_path: &Path,
server_id: StorageId,
master_key_storage: Arc<dyn AnyVaultKeyStorage>,
) -> Result<Self, Error> {
let master_key = EncryptionKey::random();
let (private, public) = DhP256HkdfSha256::gen_keypair(&mut thread_rng());
master_key_storage
.set_vault_key_for(
server_id,
KeyPair::P256 {
private,
public: public.clone(),
},
)
.map_err(|err| Error::VaultKeyStorage(err.to_string()))?;
let mut master_keys = HashMap::new();
master_keys.insert(0_u32, master_key);
let retrieved = master_key_storage
.vault_key_for(server_id)
.map_err(|err| Error::VaultKeyStorage(err.to_string()))?;
let expected_public_key_bytes = PublicKey::P256(public.clone()).to_bytes().unwrap();
let retrieved_key_matches = retrieved
.map(|r| PublicKey::from(&r).to_bytes().ok() == Some(expected_public_key_bytes))
.unwrap_or_default();
if retrieved_key_matches {
let mut serialized_master_keys = bincode::serialize(&master_keys)?;
let (encapsulated_key, aead_tag) = hpke::single_shot_seal_in_place_detached::<
ChaCha20Poly1305,
HkdfSha256,
DhP256HkdfSha256,
_,
>(
&OpModeS::Base,
&public,
b"",
&mut serialized_master_keys,
b"",
&mut thread_rng(),
)?;
let mut tag = [0_u8; 16];
tag.copy_from_slice(&aead_tag.to_bytes());
let encrypted_master_keys_payload = bincode::serialize(&HpkePayload {
encryption: PublicKeyEncryption::DhP256HkdfSha256ChaCha20,
payload: Bytes::from(serialized_master_keys),
encapsulated_key,
tag,
})?;
File::create(master_keys_path)
.and_then(move |mut file| file.write_all(&encrypted_master_keys_payload))
.map_err(|err| Error::Initializing(format!("error saving vault key: {:?}", err)))?;
Ok(Self {
_vault_public_key: PublicKey::P256(public),
master_keys,
current_master_key_id: 0,
master_key_storage,
})
} else {
Err(Error::VaultKeyStorage(String::from(
"vault key storage failed to return the same stored key during initialization",
)))
}
}
fn unseal(
master_keys_path: &Path,
server_id: StorageId,
master_key_storage: Arc<dyn AnyVaultKeyStorage>,
) -> Result<Self, Error> {
let encrypted_master_keys = std::fs::read(master_keys_path)
.map_err(|err| Error::Initializing(format!("error reading master keys: {:?}", err)))?;
let mut encrypted_master_keys =
bincode::deserialize::<HpkePayload>(&encrypted_master_keys)?;
let PublicKeyEncryption::DhP256HkdfSha256ChaCha20 = &encrypted_master_keys.encryption;
if let Some(vault_key) = master_key_storage
.vault_key_for(server_id)
.map_err(|err| Error::VaultKeyStorage(err.to_string()))?
{
let master_keys = match &vault_key {
KeyPair::P256 { private, .. } => {
let mut decryption_context =
hpke::setup_receiver::<ChaCha20Poly1305, HkdfSha256, DhP256HkdfSha256>(
&hpke::OpModeR::Base,
private,
&encrypted_master_keys.encapsulated_key,
b"",
)
.unwrap();
decryption_context
.open_in_place_detached(
&mut encrypted_master_keys.payload.0,
b"",
&AeadTag::<ChaCha20Poly1305>::from_bytes(&encrypted_master_keys.tag)
.unwrap(),
)
.unwrap();
bincode::deserialize::<HashMap<u32, EncryptionKey>>(
&encrypted_master_keys.payload,
)?
}
};
let current_master_key_id = *master_keys.keys().max().unwrap();
Ok(Self {
_vault_public_key: PublicKey::from(&vault_key),
master_keys,
current_master_key_id,
master_key_storage,
})
} else {
Err(Error::VaultKeyNotFound)
}
}
fn current_master_key(&self) -> &EncryptionKey {
self.master_keys.get(&self.current_master_key_id).unwrap()
}
pub fn encrypt_payload(
&self,
key_id: &KeyId,
payload: &[u8],
permissions: Option<&Permissions>,
) -> Result<Vec<u8>, crate::Error> {
if let Some(permissions) = permissions {
permissions.check(
encryption_key_resource_name(key_id),
&EncryptionKeyAction::Encrypt,
)?;
}
let (key, version) = match key_id {
KeyId::Master => (self.current_master_key(), self.current_master_key_id),
KeyId::Id(_) => todo!(),
KeyId::None => unreachable!(),
};
let payload = key.encrypt_payload(key_id.clone(), version, payload);
Ok(payload.to_vec())
}
pub fn decrypt_payload(
&self,
payload: &[u8],
permissions: Option<&Permissions>,
) -> Result<Vec<u8>, crate::Error> {
if let Ok(payload) = VaultPayload::from_slice(payload).map_err(|err| {
Error::Encryption(format!("error deserializing encrypted payload: {:?}", err))
}) {
self.decrypt(&payload, permissions)
} else {
Ok(payload.to_vec())
}
}
fn decrypt(
&self,
payload: &VaultPayload<'_>,
permissions: Option<&Permissions>,
) -> Result<Vec<u8>, crate::Error> {
if let Some(permissions) = permissions {
permissions.check(
encryption_key_resource_name(&payload.key_id),
&EncryptionKeyAction::Decrypt,
)?;
}
let key = match &payload.key_id {
KeyId::Master => self.current_master_key(),
KeyId::Id(_) => todo!(),
KeyId::None => unreachable!(),
};
Ok(key.decrypt_payload(payload)?)
}
}
pub trait VaultKeyStorage: Send + Sync + Debug + 'static {
type Error: Display;
fn set_vault_key_for(&self, storage_id: StorageId, key: KeyPair) -> Result<(), Self::Error>;
fn vault_key_for(&self, storage_id: StorageId) -> Result<Option<KeyPair>, Self::Error>;
}
#[derive(Serialize, Deserialize)]
struct EncryptionKey([u8; 32], #[serde(skip)] Option<region::LockGuard>);
impl EncryptionKey {
pub fn new(secret: [u8; 32]) -> Self {
let mut new_key = Self(secret, None);
new_key.lock_memory();
new_key
}
pub fn key(&self) -> &[u8] {
&self.0
}
pub fn lock_memory(&mut self) {
if self.1.is_none() {
match region::lock(self.key().as_ptr(), self.key().len()) {
Ok(guard) => self.1 = Some(guard),
Err(err) => log::error!("Security Warning: Unable to lock memory {:?}", err),
}
}
}
pub fn random() -> Self {
Self::new(thread_rng().gen())
}
pub fn encrypt_payload(
&self,
key_id: KeyId,
key_version: u32,
payload: &[u8],
) -> VaultPayload<'static> {
let mut rng = thread_rng();
let nonce: [u8; 24] = rng.gen();
self.encrypt_payload_with_nonce(key_id, key_version, payload, &nonce)
}
pub fn encrypt_payload_with_nonce(
&self,
key_id: KeyId,
key_version: u32,
payload: &[u8],
nonce: &[u8],
) -> VaultPayload<'static> {
let encrypted = XChaCha20Poly1305::new(GenericArray::from_slice(&self.0))
.encrypt(
GenericArray::from_slice(nonce),
Payload {
msg: payload,
aad: b"",
},
)
.unwrap();
VaultPayload {
key_id,
encryption: Encryption::XChaCha20Poly1305,
payload: Cow::Owned(encrypted),
nonce: Cow::Owned(nonce.to_vec()),
key_version,
}
}
pub fn decrypt_payload(&self, payload: &VaultPayload<'_>) -> Result<Vec<u8>, Error> {
let encrypted = match payload.encryption {
Encryption::XChaCha20Poly1305 => {
XChaCha20Poly1305::new(GenericArray::from_slice(&self.0)).decrypt(
GenericArray::from_slice(&payload.nonce),
Payload {
msg: &payload.payload,
aad: b"",
},
)?
}
};
Ok(encrypted)
}
}
impl Drop for EncryptionKey {
fn drop(&mut self) {
self.0.zeroize();
}
}
impl Debug for EncryptionKey {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("PrivateKey").finish_non_exhaustive()
}
}
pub trait AnyVaultKeyStorage: Send + Sync + Debug + 'static {
fn vault_key_for(&self, storage_id: StorageId) -> Result<Option<KeyPair>, Error>;
fn set_vault_key_for(&self, storage_id: StorageId, key: KeyPair) -> Result<(), Error>;
}
impl<T> AnyVaultKeyStorage for T
where
T: VaultKeyStorage + 'static,
{
fn vault_key_for(&self, server_id: StorageId) -> Result<Option<KeyPair>, Error> {
VaultKeyStorage::vault_key_for(self, server_id)
.map_err(|err| Error::VaultKeyStorage(err.to_string()))
}
fn set_vault_key_for(&self, server_id: StorageId, key: KeyPair) -> Result<(), Error> {
VaultKeyStorage::set_vault_key_for(self, server_id, key)
.map_err(|err| Error::VaultKeyStorage(err.to_string()))
}
}
#[derive(Debug, Clone)]
pub struct LocalVaultKeyStorage {
directory: PathBuf,
}
impl LocalVaultKeyStorage {
pub fn new<P: AsRef<Path>>(path: P) -> Result<Self, std::io::Error> {
let directory = path.as_ref().to_owned();
if !directory.exists() {
fs::create_dir_all(&directory)?;
}
Ok(Self { directory })
}
}
#[derive(thiserror::Error, Debug)]
pub enum LocalVaultKeyStorageError {
#[error("io error: {0}")]
Io(#[from] std::io::Error),
#[error("serialization error: {0}")]
Serialization(#[from] bincode::Error),
#[error("file was not the correct size")]
InvalidFile,
}
impl VaultKeyStorage for LocalVaultKeyStorage {
type Error = LocalVaultKeyStorageError;
fn vault_key_for(&self, server_id: StorageId) -> Result<Option<KeyPair>, Self::Error> {
let server_file = self.directory.join(server_id.to_string());
if !server_file.exists() {
return Ok(None);
}
let mut contents = File::open(server_file).and_then(|mut f| {
let mut bytes = Vec::new();
f.read_to_end(&mut bytes).map(|_| bytes)
})?;
let key = bincode::deserialize::<KeyPair>(&contents)?;
contents.zeroize();
Ok(Some(key))
}
fn set_vault_key_for(&self, server_id: StorageId, key: KeyPair) -> Result<(), Self::Error> {
let server_file = self.directory.join(server_id.to_string());
let bytes = bincode::serialize(&key)?;
File::create(server_file).and_then(|mut file| file.write_all(&bytes))?;
Ok(())
}
}
#[derive(Serialize, Deserialize)]
struct VaultPayload<'a> {
key_id: KeyId,
key_version: u32,
encryption: Encryption,
payload: Cow<'a, [u8]>,
nonce: Cow<'a, [u8]>,
}
impl<'a> VaultPayload<'a> {
fn from_slice(bytes: &'a [u8]) -> Result<Self, Error> {
bincode::deserialize(bytes).map_err(|err| {
Error::Encryption(format!("error deserializing encrypted payload: {:?}", err))
})
}
fn to_vec(&self) -> Vec<u8> {
bincode::serialize(self).unwrap()
}
}
#[derive(Serialize, Deserialize)]
struct HpkePayload {
encryption: PublicKeyEncryption,
payload: Bytes,
tag: [u8; 16],
encapsulated_key: <DhP256HkdfSha256 as Kem>::EncappedKey,
}
#[derive(Serialize, Deserialize)]
enum Encryption {
XChaCha20Poly1305,
}
#[derive(Serialize, Deserialize)]
enum PublicKeyEncryption {
DhP256HkdfSha256ChaCha20,
}
#[cfg(test)]
mod tests {
use super::*;
#[derive(Debug)]
struct NullKeyStorage;
impl VaultKeyStorage for NullKeyStorage {
type Error = anyhow::Error;
fn set_vault_key_for(
&self,
_storage_id: StorageId,
_key: KeyPair,
) -> Result<(), Self::Error> {
unreachable!()
}
fn vault_key_for(&self, _storage_id: StorageId) -> Result<Option<KeyPair>, Self::Error> {
unreachable!()
}
}
fn random_null_vault() -> Vault {
let mut master_keys = HashMap::new();
master_keys.insert(0, EncryptionKey::random());
let (_, public_key) = <DhP256HkdfSha256 as Kem>::gen_keypair(&mut thread_rng());
Vault {
_vault_public_key: PublicKey::P256(public_key),
master_keys,
current_master_key_id: 0,
master_key_storage: Arc::new(NullKeyStorage),
}
}
#[test]
fn vault_encryption_test() {
let vault = random_null_vault();
let encrypted = vault
.encrypt_payload(&KeyId::Master, b"hello", None)
.unwrap();
let decrypted = vault.decrypt_payload(&encrypted, None).unwrap();
assert_eq!(decrypted, b"hello");
}
#[test]
fn vault_permissions_test() {
let vault = random_null_vault();
assert!(matches!(
vault.encrypt_payload(&KeyId::Master, b"hello", Some(&Permissions::default()),),
Err(crate::Error::Core(bonsaidb_core::Error::PermissionDenied(
_
)))
));
let encrypted = vault
.encrypt_payload(&KeyId::Master, b"hello", None)
.unwrap();
assert!(matches!(
vault.decrypt_payload(&encrypted, Some(&Permissions::default())),
Err(crate::Error::Core(bonsaidb_core::Error::PermissionDenied(
_
)))
));
}
}