forked from ucan-wg/rs-ucan
/
envelope.rs
237 lines (207 loc) · 7.65 KB
/
envelope.rs
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use crate::{capsule::Capsule, crypto::varsig, did::Did};
use libipld_core::{
cid::Cid,
codec::{Codec, Encode},
error::Result,
ipld::Ipld,
multihash::{Code, MultihashDigest},
};
use signature::Verifier;
use signature::{SignatureEncoding, Signer};
use std::collections::BTreeMap;
use thiserror::Error;
pub trait Envelope: Sized {
type DID: Did;
type Payload: Clone + Capsule + TryFrom<Ipld> + Into<Ipld>;
type VarsigHeader: varsig::Header<Self::Encoder> + Clone;
type Encoder: Codec + TryFrom<u64> + Into<u64>;
fn varsig_header(&self) -> &Self::VarsigHeader;
fn signature(&self) -> &<Self::DID as Did>::Signature;
fn payload(&self) -> &Self::Payload;
fn verifier(&self) -> &Self::DID;
fn construct(
varsig_header: Self::VarsigHeader,
signature: <Self::DID as Did>::Signature,
payload: Self::Payload,
) -> Self;
fn to_ipld_envelope(&self) -> Ipld {
let wrapped_payload: Ipld =
BTreeMap::from_iter([(Self::Payload::TAG.into(), self.payload().clone().into())])
.into();
let header_bytes: Vec<u8> = (*self.varsig_header()).clone().into();
let header: Ipld = vec![header_bytes.into(), wrapped_payload].into();
let sig_bytes: Ipld = self.signature().to_vec().into();
vec![sig_bytes.into(), header].into()
}
fn try_from_ipld_envelope(
ipld: Ipld,
) -> Result<Self, FromIpldError<<Self::Payload as TryFrom<Ipld>>::Error>> {
if let Ipld::List(list) = ipld {
if let [Ipld::Bytes(sig), Ipld::List(inner)] = list.as_slice() {
if let [Ipld::Bytes(varsig_header), Ipld::Map(btree)] = inner.as_slice() {
if let (1, Some(inner)) = (
btree.len(),
btree.get(<Self::Payload as Capsule>::TAG.into()),
) {
let payload = Self::Payload::try_from(inner.clone())
.map_err(FromIpldError::CannotParsePayload)?;
let varsig_header = Self::VarsigHeader::try_from(varsig_header.as_slice())
.map_err(|_| FromIpldError::CannotParseVarsigHeader)?;
let signature = <Self::DID as Did>::Signature::try_from(sig.as_slice())
.map_err(|_| FromIpldError::CannotParseSignature)?;
Ok(Self::construct(varsig_header, signature, payload))
} else {
Err(FromIpldError::InvalidPayloadCapsule)
}
} else {
Err(FromIpldError::InvalidVarsigContainer)
}
} else {
Err(FromIpldError::InvalidSignatureContainer)
}
} else {
Err(FromIpldError::InvalidSignatureContainer)
}
}
fn varsig_encode(self, w: &mut Vec<u8>) -> Result<(), libipld_core::error::Error>
where
Ipld: Encode<Self::Encoder> + From<Self>,
{
let codec = varsig::header::Header::codec(self.varsig_header()).clone();
let ipld = Ipld::from(self);
ipld.encode(codec, w)
}
/// Attempt to sign some payload with a given signer.
///
/// # Arguments
///
/// * `signer` - The signer to use to sign the payload.
/// * `payload` - The payload to sign.
///
/// # Errors
///
/// * [`SignError`] - the payload can't be encoded or the signature fails.
// FIXME ported
fn try_sign(
signer: &<Self::DID as Did>::Signer,
varsig_header: Self::VarsigHeader,
payload: Self::Payload,
) -> Result<Self, SignError>
where
Ipld: Encode<Self::Encoder> + From<Self::Payload>, // FIXME force it to be named args not IPLD
{
Self::try_sign_generic(signer, varsig_header, payload)
}
/// Attempt to sign some payload with a given signer and specific codec.
///
/// # Arguments
///
/// * `signer` - The signer to use to sign the payload.
/// * `codec` - The codec to use to encode the payload.
/// * `payload` - The payload to sign.
///
/// # Errors
///
/// * [`SignError`] - the payload can't be encoded or the signature fails.
///
/// # Example
///
fn try_sign_generic(
signer: &<Self::DID as Did>::Signer,
varsig_header: Self::VarsigHeader,
payload: Self::Payload,
) -> Result<Self, SignError>
where
Ipld: Encode<Self::Encoder> + From<Self::Payload>,
{
let ipld: Ipld =
BTreeMap::from_iter([(Self::Payload::TAG.into(), Ipld::from(payload.clone()))]).into();
let mut buffer = vec![];
ipld.encode(*varsig::header::Header::codec(&varsig_header), &mut buffer)
.map_err(SignError::PayloadEncodingError)?;
let signature =
signature::Signer::try_sign(signer, &buffer).map_err(SignError::SignatureError)?;
Ok(Self::construct(varsig_header, signature, payload))
}
/// Attempt to validate a signature.
///
/// # Arguments
///
/// * `self` - The envelope to validate.
///
/// # Errors
///
/// * [`ValidateError`] - the payload can't be encoded or the signature fails.
///
/// # Exmaples
///
/// FIXME
fn validate_signature(&self) -> Result<(), ValidateError>
where
Ipld: Encode<Self::Encoder> + From<Self::Payload>,
{
let mut encoded = vec![];
let ipld: Ipld =
BTreeMap::from_iter([(Self::Payload::TAG.into(), self.payload().clone().into())])
.into();
ipld.encode(
*varsig::header::Header::codec(self.varsig_header()),
&mut encoded,
)
.map_err(ValidateError::PayloadEncodingError)?;
self.verifier()
.verify(&encoded, &self.signature())
.map_err(ValidateError::VerifyError)
}
fn cid(&self) -> Result<Cid, libipld_core::error::Error>
where
// Ipld: Encode<Self::Encoder> + From<Self::Payload>,
Self: Encode<Self::Encoder>,
{
let codec = varsig::header::Header::codec(self.varsig_header()).clone();
let mut ipld_buffer = vec![];
self.encode(codec, &mut ipld_buffer)?;
let multihash = Code::Sha2_256.digest(&ipld_buffer);
Ok(Cid::new_v1(
varsig::header::Header::codec(self.varsig_header())
.clone()
.into(),
multihash,
))
}
}
#[derive(Debug, Clone, PartialEq, Error)]
pub enum FromIpldError<E> {
#[error("Invalid signature container")]
InvalidSignatureContainer,
#[error("Invalid varsig container")]
InvalidVarsigContainer,
#[error("Cannot parse payload: {0}")]
CannotParsePayload(#[from] E),
#[error("Cannot parse varsig header")]
CannotParseVarsigHeader,
#[error("Cannot parse signature")]
CannotParseSignature,
#[error("Invalid payload capsule")]
InvalidPayloadCapsule,
}
/// Errors that can occur when signing a [`siganture::Envelope`][Envelope].
#[derive(Debug, Error)]
pub enum SignError {
/// Unable to encode the payload.
#[error("Unable to encode payload")]
PayloadEncodingError(#[from] libipld_core::error::Error),
/// Error while signing.
#[error("Signature error: {0}")]
SignatureError(#[from] signature::Error),
}
/// Errors that can occur when validating a [`signature::Envelope`][Envelope].
#[derive(Debug, Error)]
pub enum ValidateError {
/// Unable to encode the payload.
#[error("Unable to encode payload")]
PayloadEncodingError(#[from] libipld_core::error::Error),
/// Error while verifying the signature.
#[error("Signature verification failed: {0}")]
VerifyError(#[from] signature::Error),
}