refactor(keyholder): generalize derive_useragent_integrity_key and compute_useragent_pubkey_integrity_tag corespondenly to derive_integrity_key and compute_integrity_tag

This commit is contained in:
CleverWild
2026-04-04 12:00:39 +02:00
parent a02ef68a70
commit 78895bca5b
4 changed files with 73 additions and 49 deletions

View File

@@ -172,15 +172,15 @@ pub fn derive_seal_key(mut password: SafeCell<Vec<u8>>, salt: &Salt) -> KeyCell
key.into()
}
/// Derives a dedicated key used only for user-agent pubkey integrity tags.
pub fn derive_useragent_integrity_key(seal_key: &mut KeyCell) -> KeyCell {
/// Derives a dedicated key used for integrity tags within a specific domain.
pub fn derive_integrity_key(seal_key: &mut KeyCell, derive_tag: &[u8]) -> KeyCell {
type HmacSha256 = hmac::Hmac<sha2::Sha256>;
let mut derived = SafeCell::new(Key::default());
seal_key.0.read_inline(|seal_key_bytes| {
let mut mac = <HmacSha256 as hmac::Mac>::new_from_slice(seal_key_bytes.as_ref())
.expect("HMAC key initialization must not fail for 32-byte key");
mac.update(USERAGENT_INTEGRITY_DERIVE_TAG);
mac.update(derive_tag);
let output = mac.finalize().into_bytes();
let mut writer = derived.write();
@@ -191,25 +191,29 @@ pub fn derive_useragent_integrity_key(seal_key: &mut KeyCell) -> KeyCell {
derived.into()
}
/// Computes an integrity tag for a user-agent pubkey DB entry.
pub fn compute_useragent_pubkey_integrity_tag(
/// Computes an integrity tag for a specific domain and payload shape.
pub fn compute_integrity_tag<'a, I>(
integrity_key: &mut KeyCell,
key_type_discriminant: i32,
public_key: &[u8],
) -> [u8; 32] {
purpose_tag: &[u8],
data_parts: I,
) -> [u8; 32]
where
I: IntoIterator<Item = &'a [u8]>,
{
type HmacSha256 = hmac::Hmac<sha2::Sha256>;
let mut tag = [0u8; 32];
let mut output_tag = [0u8; 32];
integrity_key.0.read_inline(|integrity_key_bytes| {
let mut mac = <HmacSha256 as hmac::Mac>::new_from_slice(integrity_key_bytes.as_ref())
.expect("HMAC key initialization must not fail for 32-byte key");
mac.update(USERAGENT_INTEGRITY_TAG);
mac.update(&key_type_discriminant.to_be_bytes());
mac.update(public_key);
tag.copy_from_slice(&mac.finalize().into_bytes());
mac.update(purpose_tag);
for data_part in data_parts {
mac.update(data_part);
}
output_tag.copy_from_slice(&mac.finalize().into_bytes());
});
tag
output_tag
}
#[cfg(test)]
@@ -285,22 +289,41 @@ mod tests {
}
#[test]
pub fn useragent_integrity_tag_deterministic() {
pub fn integrity_tag_deterministic() {
let salt = generate_salt();
let mut seal_key = derive_seal_key(SafeCell::new(b"password".to_vec()), &salt);
let mut integrity_key = derive_useragent_integrity_key(&mut seal_key);
let t1 = compute_useragent_pubkey_integrity_tag(&mut integrity_key, 1, b"pubkey");
let t2 = compute_useragent_pubkey_integrity_tag(&mut integrity_key, 1, b"pubkey");
let mut integrity_key = derive_integrity_key(&mut seal_key, USERAGENT_INTEGRITY_DERIVE_TAG);
let key_type = 1i32.to_be_bytes();
let t1 = compute_integrity_tag(
&mut integrity_key,
USERAGENT_INTEGRITY_TAG,
[key_type.as_slice(), b"pubkey".as_ref()],
);
let t2 = compute_integrity_tag(
&mut integrity_key,
USERAGENT_INTEGRITY_TAG,
[key_type.as_slice(), b"pubkey".as_ref()],
);
assert_eq!(t1, t2);
}
#[test]
pub fn useragent_integrity_tag_changes_with_key_type() {
pub fn integrity_tag_changes_with_payload() {
let salt = generate_salt();
let mut seal_key = derive_seal_key(SafeCell::new(b"password".to_vec()), &salt);
let mut integrity_key = derive_useragent_integrity_key(&mut seal_key);
let t1 = compute_useragent_pubkey_integrity_tag(&mut integrity_key, 1, b"pubkey");
let t2 = compute_useragent_pubkey_integrity_tag(&mut integrity_key, 2, b"pubkey");
let mut integrity_key = derive_integrity_key(&mut seal_key, USERAGENT_INTEGRITY_DERIVE_TAG);
let key_type_1 = 1i32.to_be_bytes();
let key_type_2 = 2i32.to_be_bytes();
let t1 = compute_integrity_tag(
&mut integrity_key,
USERAGENT_INTEGRITY_TAG,
[key_type_1.as_slice(), b"pubkey".as_ref()],
);
let t2 = compute_integrity_tag(
&mut integrity_key,
USERAGENT_INTEGRITY_TAG,
[key_type_2.as_slice(), b"pubkey".as_ref()],
);
assert_ne!(t1, t2);
}
}

View File

@@ -32,7 +32,7 @@ enum State {
Unsealed {
root_key_history_id: i32,
root_key: KeyCell,
useragent_integrity_key: KeyCell,
integrity_key: KeyCell,
},
}
@@ -146,7 +146,8 @@ impl KeyHolder {
}
let salt = v1::generate_salt();
let mut seal_key = v1::derive_seal_key(seal_key_raw, &salt);
let useragent_integrity_key = v1::derive_useragent_integrity_key(&mut seal_key);
let integrity_key =
v1::derive_integrity_key(&mut seal_key, v1::USERAGENT_INTEGRITY_DERIVE_TAG);
let mut root_key = KeyCell::new_secure_random();
// Zero nonces are fine because they are one-time
@@ -195,7 +196,7 @@ impl KeyHolder {
self.state = State::Unsealed {
root_key,
root_key_history_id,
useragent_integrity_key,
integrity_key,
};
info!("Keyholder bootstrapped successfully");
@@ -229,7 +230,8 @@ impl KeyHolder {
Error::BrokenDatabase
})?;
let mut seal_key = v1::derive_seal_key(seal_key_raw, &salt);
let useragent_integrity_key = v1::derive_useragent_integrity_key(&mut seal_key);
let integrity_key =
v1::derive_integrity_key(&mut seal_key, v1::USERAGENT_INTEGRITY_DERIVE_TAG);
let mut root_key = SafeCell::new(current_key.ciphertext.clone());
@@ -253,7 +255,7 @@ impl KeyHolder {
error!(?err, "Broken database: invalid encryption key size");
Error::BrokenDatabase
})?,
useragent_integrity_key,
integrity_key,
};
info!("Keyholder unsealed successfully");
@@ -263,23 +265,19 @@ impl KeyHolder {
// Decrypts the `aead_encrypted` entry with the given ID and returns the plaintext
#[message]
pub fn sign_useragent_pubkey_integrity_tag(
pub fn sign_integrity_tag(
&mut self,
public_key: Vec<u8>,
key_type: models::KeyType,
purpose_tag: Vec<u8>,
data_parts: Vec<Vec<u8>>,
) -> Result<Vec<u8>, Error> {
let State::Unsealed {
useragent_integrity_key,
..
} = &mut self.state
else {
let State::Unsealed { integrity_key, .. } = &mut self.state else {
return Err(Error::NotBootstrapped);
};
let tag = v1::compute_useragent_pubkey_integrity_tag(
useragent_integrity_key,
key_type as i32,
&public_key,
let tag = v1::compute_integrity_tag(
integrity_key,
&purpose_tag,
data_parts.iter().map(Vec::as_slice),
);
Ok(tag.to_vec())
}

View File

@@ -8,7 +8,7 @@ use super::Error;
use crate::{
actors::{
bootstrap::ConsumeToken,
keyholder::{self, SignUseragentPubkeyIntegrityTag},
keyholder::{self, SignIntegrityTag},
user_agent::{AuthPublicKey, UserAgentConnection, auth::Outbound},
},
db::schema,
@@ -257,9 +257,12 @@ where
.conn
.actors
.key_holder
.ask(SignUseragentPubkeyIntegrityTag {
public_key: pubkey.to_stored_bytes(),
key_type: pubkey.key_type(),
.ask(SignIntegrityTag {
purpose_tag: keyholder::encryption::v1::USERAGENT_INTEGRITY_TAG.to_vec(),
data_parts: vec![
(pubkey.key_type() as i32).to_be_bytes().to_vec(),
pubkey.to_stored_bytes(),
],
})
.await;

View File

@@ -23,7 +23,7 @@ use crate::{
evm::{
Generate, ListWallets, UseragentCreateGrant, UseragentDeleteGrant, UseragentListGrants,
},
keyholder::{self, Bootstrap, SignUseragentPubkeyIntegrityTag, TryUnseal},
keyholder::{self, Bootstrap, SignIntegrityTag, TryUnseal},
user_agent::session::{
UserAgentSession,
state::{UnsealContext, UserAgentEvents, UserAgentStates},
@@ -111,14 +111,14 @@ impl UserAgentSession {
.props
.actors
.key_holder
.ask(SignUseragentPubkeyIntegrityTag {
public_key,
key_type,
.ask(SignIntegrityTag {
purpose_tag: keyholder::encryption::v1::USERAGENT_INTEGRITY_TAG.to_vec(),
data_parts: vec![(key_type as i32).to_be_bytes().to_vec(), public_key],
})
.await
.map_err(|err| {
error!(?err, "Failed to sign user-agent pubkey integrity tag");
Error::internal("Failed to sign user-agent pubkey integrity tag")
error!(?err, "Failed to sign integrity tag");
Error::internal("Failed to sign integrity tag")
})?;
updates.push((id, tag));
}