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|
//! Serializer for signed version response data
//!
//! Signing attaches a signature, and leaves the original JSON data in the "signed" key:
//!
//! ```ignore
//! {
//! "signature": {
//! "keyid": "...",
//! "sig": "..."
//! }
//! "signed": {
//! ...
//! }
//! }
//! ```
use anyhow::Context;
use serde::Serialize;
use super::{PartialSignedResponse, Response, ResponseSignature, SignedResponse, key};
impl SignedResponse {
pub fn sign(key: key::SecretKey, response: Response) -> anyhow::Result<SignedResponse> {
// Refuse to sign expired data
if response.metadata_expiry < chrono::Utc::now() {
anyhow::bail!("Signing failed since the data has expired");
}
// Sign it
let partial_signed = sign(&key, &response)?;
// Attempt to deserialize signed part as response
// Probably unnecessary; mostly in case canonical JSON lost something
let response: Response = serde_json::from_value(partial_signed.signed)?;
Ok(SignedResponse {
signatures: partial_signed.signatures,
signed: response,
})
}
}
/// Serialize JSON to bytes, with a signature attached, signed using `key`
fn sign<T: Serialize>(
key: &key::SecretKey,
unsigned_value: &T,
) -> anyhow::Result<PartialSignedResponse> {
// Serialize unsigned data to canonical JSON
let unsigned_canon =
json_canon::to_vec(&unsigned_value).context("Failed to canonicalize JSON")?;
// Generate signature for the canonical JSON
let sig = key.sign(&unsigned_canon);
// Deserialize in case something was lost during serialization
let signed =
serde_json::from_slice(&unsigned_canon).context("Failed to deserialize canonical JSON")?;
// Attach signature
Ok(PartialSignedResponse {
signatures: vec![ResponseSignature::Ed25519 {
keyid: key.pubkey(),
sig,
}],
// Attach now-signed data
signed,
})
}
#[cfg(test)]
mod test {
use super::*;
use crate::format::deserializer::deserialize_and_verify;
use serde_json::json;
use vec1::vec1;
#[test]
fn test_sign() -> anyhow::Result<()> {
// Generate key and data
let key = key::SecretKey::generate();
let pubkey = key.pubkey();
let data = json!({
"stuff": "I can prove that I wrote this"
});
// Verify that we can deserialize and verify the data
let partial = sign(&key, &data).context("Signing failed")?;
assert!(
matches!(&partial.signatures[0], ResponseSignature::Ed25519 {
keyid,
..
} if keyid == &pubkey)
);
let bytes = serde_json::to_vec(&partial)?;
deserialize_and_verify(&vec1![pubkey.clone()], &bytes)?;
// Verify that an irrelevant key is ignored
let invalid_key = key::SecretKey::generate();
let invalid_pubkey = invalid_key.pubkey();
deserialize_and_verify(&vec1![pubkey.clone(), invalid_pubkey.clone()], &bytes)?;
// Wrong public key only fails
deserialize_and_verify(&vec1![invalid_pubkey], &bytes).unwrap_err();
Ok(())
}
#[test]
fn test_sign_multiple() -> anyhow::Result<()> {
// Generate keys and data
let key = key::SecretKey::generate();
let pubkey = key.pubkey();
let key2 = key::SecretKey::generate();
let pubkey2 = key2.pubkey();
let invalid_key = key::SecretKey::generate();
let invalid_pubkey = invalid_key.pubkey();
let data = json!({
"stuff": "I can prove that I wrote this"
});
// Sign with two keys
let mut partial = sign(&key, &data).context("Signing failed")?;
let partial2 = sign(&key2, &data).context("Signing failed")?;
partial.signatures.extend(partial2.signatures);
let bytes = serde_json::to_vec(&partial)?;
// Accept either (or both) keys
deserialize_and_verify(&vec1![pubkey.clone(), pubkey2.clone()], &bytes)?;
deserialize_and_verify(&vec1![pubkey2.clone()], &bytes)?;
deserialize_and_verify(&vec1![pubkey.clone()], &bytes)?;
// Ignore irrelevant key
deserialize_and_verify(
&vec1![pubkey.clone(), pubkey2.clone(), invalid_pubkey.clone()],
&bytes,
)?;
deserialize_and_verify(&vec1![pubkey2, invalid_pubkey.clone()], &bytes)?;
deserialize_and_verify(&vec1![invalid_pubkey.clone(), pubkey], &bytes)?;
// Using wrong public key fails
deserialize_and_verify(&vec1![invalid_pubkey], &bytes).unwrap_err();
Ok(())
}
}
|
