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TaggedHash for BOLT 12 signing function

Browse source 
The function used to sign BOLT 12 messages only takes a message digest.
This doesn't allow signers to independently verify the message before
signing nor does it allow them to derive the necessary signing keys, if
needed.

Introduce a TaggedHash wrapper for a message digest, which each unsigned
BOLT 12 message type constructs upon initialization. Change the signing
function to take AsRef<TaggedHash>, which each unsigned type implements.
This allows the signing function to take any unsigned message and obtain
its tagged hash.
This commit is contained in:
Jeffrey Czyz 2023-02-27 14:23:05 -06:00
parent 4bb4a970e8
commit 1811ebff32
No known key found for this signature in database
GPG key ID: 3A4E08275D5E96D2
7 changed files with 187 additions and 113 deletions
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10
fuzz/src/invoice_request_deser.rs
View file

@ -38,7 +38,7 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
if signing_pubkey == odd_pubkey || signing_pubkey == even_pubkey {
unsigned_invoice
.sign::<_, Infallible>(
|digest| Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &keys))
|message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
)
.unwrap()
.write(&mut buffer)
@ -46,7 +46,7 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
} else {
unsigned_invoice
.sign::<_, Infallible>(
|digest| Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &keys))
|message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
)
.unwrap_err();
}
@ -69,9 +69,9 @@ fn privkey(byte: u8) -> SecretKey {
SecretKey::from_slice(&[byte; 32]).unwrap()
}
fn build_response<'a, T: secp256k1::Signing + secp256k1::Verification>(
invoice_request: &'a InvoiceRequest, secp_ctx: &Secp256k1<T>
) -> Result<UnsignedBolt12Invoice<'a>, Bolt12SemanticError> {
fn build_response<T: secp256k1::Signing + secp256k1::Verification>(
invoice_request: &InvoiceRequest, secp_ctx: &Secp256k1<T>
) -> Result<UnsignedBolt12Invoice, Bolt12SemanticError> {
let entropy_source = Randomness {};
let paths = vec![
BlindedPath::new_for_message(&[pubkey(43), pubkey(44), pubkey(42)], &entropy_source, secp_ctx).unwrap(),

8
fuzz/src/offer_deser.rs
View file

@ -30,7 +30,7 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
if let Ok(invoice_request) = build_response(&offer, pubkey) {
invoice_request
.sign::<_, Infallible>(
|digest| Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &keys))
|message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
)
.unwrap()
.write(&mut buffer)
@ -39,9 +39,9 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
}
}
fn build_response<'a>(
offer: &'a Offer, pubkey: PublicKey
) -> Result<UnsignedInvoiceRequest<'a>, Bolt12SemanticError> {
fn build_response(
offer: &Offer, pubkey: PublicKey
) -> Result<UnsignedInvoiceRequest, Bolt12SemanticError> {
let mut builder = offer.request_invoice(vec![42; 64], pubkey)?;
builder = match offer.amount() {

8
fuzz/src/refund_deser.rs
View file

@ -34,7 +34,7 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
if let Ok(invoice) = build_response(&refund, pubkey, &secp_ctx) {
invoice
.sign::<_, Infallible>(
|digest| Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &keys))
|message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
)
.unwrap()
.write(&mut buffer)
@ -58,9 +58,9 @@ fn privkey(byte: u8) -> SecretKey {
SecretKey::from_slice(&[byte; 32]).unwrap()
}
fn build_response<'a, T: secp256k1::Signing + secp256k1::Verification>(
refund: &'a Refund, signing_pubkey: PublicKey, secp_ctx: &Secp256k1<T>
) -> Result<UnsignedBolt12Invoice<'a>, Bolt12SemanticError> {
fn build_response<T: secp256k1::Signing + secp256k1::Verification>(
refund: &Refund, signing_pubkey: PublicKey, secp_ctx: &Secp256k1<T>
) -> Result<UnsignedBolt12Invoice, Bolt12SemanticError> {
let entropy_source = Randomness {};
let paths = vec![
BlindedPath::new_for_message(&[pubkey(43), pubkey(44), pubkey(42)], &entropy_source, secp_ctx).unwrap(),

85
lightning/src/offers/invoice.rs
View file

@ -55,7 +55,9 @@
//! .allow_mpp()
//! .fallback_v0_p2wpkh(&wpubkey_hash)
//! .build()?
//! .sign::<_, Infallible>(|digest| Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &keys)))
//! .sign::<_, Infallible>(
//! |message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
//! )
//! .expect("failed verifying signature")
//! .write(&mut buffer)
//! .unwrap();
@ -84,7 +86,9 @@
//! .allow_mpp()
//! .fallback_v0_p2wpkh(&wpubkey_hash)
//! .build()?
//! .sign::<_, Infallible>(|digest| Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &keys)))
//! .sign::<_, Infallible>(
//! |message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
//! )
//! .expect("failed verifying signature")
//! .write(&mut buffer)
//! .unwrap();
@ -97,11 +101,11 @@ use bitcoin::blockdata::constants::ChainHash;
use bitcoin::hash_types::{WPubkeyHash, WScriptHash};
use bitcoin::hashes::Hash;
use bitcoin::network::constants::Network;
use bitcoin::secp256k1::{KeyPair, Message, PublicKey, Secp256k1, self};
use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, self};
use bitcoin::secp256k1::schnorr::Signature;
use bitcoin::util::address::{Address, Payload, WitnessVersion};
use bitcoin::util::schnorr::TweakedPublicKey;
use core::convert::{Infallible, TryFrom};
use core::convert::{AsRef, Infallible, TryFrom};
use core::time::Duration;
use crate::io;
use crate::blinded_path::BlindedPath;
@ -110,7 +114,7 @@ use crate::ln::features::{BlindedHopFeatures, Bolt12InvoiceFeatures};
use crate::ln::inbound_payment::ExpandedKey;
use crate::ln::msgs::DecodeError;
use crate::offers::invoice_request::{INVOICE_REQUEST_PAYER_ID_TYPE, INVOICE_REQUEST_TYPES, IV_BYTES as INVOICE_REQUEST_IV_BYTES, InvoiceRequest, InvoiceRequestContents, InvoiceRequestTlvStream, InvoiceRequestTlvStreamRef};
use crate::offers::merkle::{SignError, SignatureTlvStream, SignatureTlvStreamRef, TlvStream, WithoutSignatures, self};
use crate::offers::merkle::{SignError, SignatureTlvStream, SignatureTlvStreamRef, TaggedHash, TlvStream, WithoutSignatures, self};
use crate::offers::offer::{Amount, OFFER_TYPES, OfferTlvStream, OfferTlvStreamRef};
use crate::offers::parse::{Bolt12ParseError, Bolt12SemanticError, ParsedMessage};
use crate::offers::payer::{PAYER_METADATA_TYPE, PayerTlvStream, PayerTlvStreamRef};
@ -126,7 +130,8 @@ use std::time::SystemTime;
const DEFAULT_RELATIVE_EXPIRY: Duration = Duration::from_secs(7200);
pub(super) const SIGNATURE_TAG: &'static str = concat!("lightning", "invoice", "signature");
/// Tag for the hash function used when signing a [`Bolt12Invoice`]'s merkle root.
pub const SIGNATURE_TAG: &'static str = concat!("lightning", "invoice", "signature");
/// Builds a [`Bolt12Invoice`] from either:
/// - an [`InvoiceRequest`] for the "offer to be paid" flow or
@ -331,7 +336,7 @@ impl<'a, S: SigningPubkeyStrategy> InvoiceBuilder<'a, S> {
impl<'a> InvoiceBuilder<'a, ExplicitSigningPubkey> {
/// Builds an unsigned [`Bolt12Invoice`] after checking for valid semantics. It can be signed by
/// [`UnsignedBolt12Invoice::sign`].
pub fn build(self) -> Result<UnsignedBolt12Invoice<'a>, Bolt12SemanticError> {
pub fn build(self) -> Result<UnsignedBolt12Invoice, Bolt12SemanticError> {
#[cfg(feature = "std")] {
if self.invoice.is_offer_or_refund_expired() {
return Err(Bolt12SemanticError::AlreadyExpired);
@ -339,7 +344,7 @@ impl<'a> InvoiceBuilder<'a, ExplicitSigningPubkey> {
}
let InvoiceBuilder { invreq_bytes, invoice, .. } = self;
Ok(UnsignedBolt12Invoice { invreq_bytes, invoice })
Ok(UnsignedBolt12Invoice::new(invreq_bytes, invoice))
}
}
@ -355,23 +360,42 @@ impl<'a> InvoiceBuilder<'a, DerivedSigningPubkey> {
}
let InvoiceBuilder { invreq_bytes, invoice, keys, .. } = self;
let unsigned_invoice = UnsignedBolt12Invoice { invreq_bytes, invoice };
let unsigned_invoice = UnsignedBolt12Invoice::new(invreq_bytes, invoice);
let keys = keys.unwrap();
let invoice = unsigned_invoice
.sign::<_, Infallible>(|digest| Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &keys)))
.sign::<_, Infallible>(
|message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
)
.unwrap();
Ok(invoice)
}
}
/// A semantically valid [`Bolt12Invoice`] that hasn't been signed.
pub struct UnsignedBolt12Invoice<'a> {
invreq_bytes: &'a Vec<u8>,
pub struct UnsignedBolt12Invoice {
bytes: Vec<u8>,
invoice: InvoiceContents,
tagged_hash: TaggedHash,
}
impl<'a> UnsignedBolt12Invoice<'a> {
impl UnsignedBolt12Invoice {
fn new(invreq_bytes: &[u8], invoice: InvoiceContents) -> Self {
// Use the invoice_request bytes instead of the invoice_request TLV stream as the latter may
// have contained unknown TLV records, which are not stored in `InvoiceRequestContents` or
// `RefundContents`.
let (_, _, _, invoice_tlv_stream) = invoice.as_tlv_stream();
let invoice_request_bytes = WithoutSignatures(invreq_bytes);
let unsigned_tlv_stream = (invoice_request_bytes, invoice_tlv_stream);
let mut bytes = Vec::new();
unsigned_tlv_stream.write(&mut bytes).unwrap();
let tagged_hash = TaggedHash::new(SIGNATURE_TAG, &bytes);
Self { bytes, invoice, tagged_hash }
}
/// The public key corresponding to the key needed to sign the invoice.
pub fn signing_pubkey(&self) -> PublicKey {
self.invoice.fields().signing_pubkey
@ -380,37 +404,33 @@ impl<'a> UnsignedBolt12Invoice<'a> {
/// Signs the invoice using the given function.
///
/// This is not exported to bindings users as functions aren't currently mapped.
pub fn sign<F, E>(self, sign: F) -> Result<Bolt12Invoice, SignError<E>>
pub fn sign<F, E>(mut self, sign: F) -> Result<Bolt12Invoice, SignError<E>>
where
F: FnOnce(&Message) -> Result<Signature, E>
F: FnOnce(&Self) -> Result<Signature, E>
{
// Use the invoice_request bytes instead of the invoice_request TLV stream as the latter may
// have contained unknown TLV records, which are not stored in `InvoiceRequestContents` or
// `RefundContents`.
let (_, _, _, invoice_tlv_stream) = self.invoice.as_tlv_stream();
let invoice_request_bytes = WithoutSignatures(self.invreq_bytes);
let unsigned_tlv_stream = (invoice_request_bytes, invoice_tlv_stream);
let mut bytes = Vec::new();
unsigned_tlv_stream.write(&mut bytes).unwrap();
let pubkey = self.invoice.fields().signing_pubkey;
let signature = merkle::sign_message(sign, SIGNATURE_TAG, &bytes, pubkey)?;
let signature = merkle::sign_message(sign, &self, pubkey)?;
// Append the signature TLV record to the bytes.
let signature_tlv_stream = SignatureTlvStreamRef {
signature: Some(&signature),
};
signature_tlv_stream.write(&mut bytes).unwrap();
signature_tlv_stream.write(&mut self.bytes).unwrap();
Ok(Bolt12Invoice {
bytes,
bytes: self.bytes,
contents: self.invoice,
signature,
})
}
}
impl AsRef<TaggedHash> for UnsignedBolt12Invoice {
fn as_ref(&self) -> &TaggedHash {
&self.tagged_hash
}
}
/// A `Bolt12Invoice` is a payment request, typically corresponding to an [`Offer`] or a [`Refund`].
///
/// An invoice may be sent in response to an [`InvoiceRequest`] in the case of an offer or sent
@ -1686,15 +1706,14 @@ mod tests {
.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
.build().unwrap()
.sign(payer_sign).unwrap();
let mut unsigned_invoice = invoice_request
let mut invoice_builder = invoice_request
.respond_with_no_std(payment_paths(), payment_hash(), now()).unwrap()
.fallback_v0_p2wsh(&script.wscript_hash())
.fallback_v0_p2wpkh(&pubkey.wpubkey_hash().unwrap())
.fallback_v1_p2tr_tweaked(&tweaked_pubkey)
.build().unwrap();
.fallback_v1_p2tr_tweaked(&tweaked_pubkey);
// Only standard addresses will be included.
let fallbacks = unsigned_invoice.invoice.fields_mut().fallbacks.as_mut().unwrap();
let fallbacks = invoice_builder.invoice.fields_mut().fallbacks.as_mut().unwrap();
// Non-standard addresses
fallbacks.push(FallbackAddress { version: 1, program: vec![0u8; 41] });
fallbacks.push(FallbackAddress { version: 2, program: vec![0u8; 1] });
@ -1703,7 +1722,7 @@ mod tests {
fallbacks.push(FallbackAddress { version: 1, program: vec![0u8; 33] });
fallbacks.push(FallbackAddress { version: 2, program: vec![0u8; 40] });
let invoice = unsigned_invoice.sign(recipient_sign).unwrap();
let invoice = invoice_builder.build().unwrap().sign(recipient_sign).unwrap();
let mut buffer = Vec::new();
invoice.write(&mut buffer).unwrap();

108
lightning/src/offers/invoice_request.rs
View file

@ -44,7 +44,9 @@
//! .quantity(5)?
//! .payer_note("foo".to_string())
//! .build()?
//! .sign::<_, Infallible>(|digest| Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &keys)))
//! .sign::<_, Infallible>(
//! |message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
//! )
//! .expect("failed verifying signature")
//! .write(&mut buffer)
//! .unwrap();
@ -54,9 +56,9 @@
use bitcoin::blockdata::constants::ChainHash;
use bitcoin::network::constants::Network;
use bitcoin::secp256k1::{KeyPair, Message, PublicKey, Secp256k1, self};
use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, self};
use bitcoin::secp256k1::schnorr::Signature;
use core::convert::{Infallible, TryFrom};
use core::convert::{AsRef, Infallible, TryFrom};
use core::ops::Deref;
use crate::sign::EntropySource;
use crate::io;
@ -66,7 +68,7 @@ use crate::ln::features::InvoiceRequestFeatures;
use crate::ln::inbound_payment::{ExpandedKey, IV_LEN, Nonce};
use crate::ln::msgs::DecodeError;
use crate::offers::invoice::{BlindedPayInfo, DerivedSigningPubkey, ExplicitSigningPubkey, InvoiceBuilder};
use crate::offers::merkle::{SignError, SignatureTlvStream, SignatureTlvStreamRef, self};
use crate::offers::merkle::{SignError, SignatureTlvStream, SignatureTlvStreamRef, TaggedHash, self};
use crate::offers::offer::{Offer, OfferContents, OfferTlvStream, OfferTlvStreamRef};
use crate::offers::parse::{Bolt12ParseError, ParsedMessage, Bolt12SemanticError};
use crate::offers::payer::{PayerContents, PayerTlvStream, PayerTlvStreamRef};
@ -76,7 +78,8 @@ use crate::util::string::PrintableString;
use crate::prelude::*;
const SIGNATURE_TAG: &'static str = concat!("lightning", "invoice_request", "signature");
/// Tag for the hash function used when signing an [`InvoiceRequest`]'s merkle root.
pub const SIGNATURE_TAG: &'static str = concat!("lightning", "invoice_request", "signature");
pub(super) const IV_BYTES: &[u8; IV_LEN] = b"LDK Invreq ~~~~~";
@ -214,7 +217,7 @@ impl<'a, 'b, P: PayerIdStrategy, T: secp256k1::Signing> InvoiceRequestBuilder<'a
}
fn build_with_checks(mut self) -> Result<
(UnsignedInvoiceRequest<'a>, Option<KeyPair>, Option<&'b Secp256k1<T>>),
(UnsignedInvoiceRequest, Option<KeyPair>, Option<&'b Secp256k1<T>>),
Bolt12SemanticError
> {
#[cfg(feature = "std")] {
@ -245,7 +248,7 @@ impl<'a, 'b, P: PayerIdStrategy, T: secp256k1::Signing> InvoiceRequestBuilder<'a
}
fn build_without_checks(mut self) ->
(UnsignedInvoiceRequest<'a>, Option<KeyPair>, Option<&'b Secp256k1<T>>)
(UnsignedInvoiceRequest, Option<KeyPair>, Option<&'b Secp256k1<T>>)
{
// Create the metadata for stateless verification of a Bolt12Invoice.
let mut keys = None;
@ -275,22 +278,20 @@ impl<'a, 'b, P: PayerIdStrategy, T: secp256k1::Signing> InvoiceRequestBuilder<'a
debug_assert!(self.payer_id.is_some());
let payer_id = self.payer_id.unwrap();
let unsigned_invoice = UnsignedInvoiceRequest {
offer: self.offer,
invoice_request: InvoiceRequestContents {
inner: self.invoice_request,
payer_id,
},
let invoice_request = InvoiceRequestContents {
inner: self.invoice_request,
payer_id,
};
let unsigned_invoice_request = UnsignedInvoiceRequest::new(self.offer, invoice_request);
(unsigned_invoice, keys, secp_ctx)
(unsigned_invoice_request, keys, secp_ctx)
}
}
impl<'a, 'b, T: secp256k1::Signing> InvoiceRequestBuilder<'a, 'b, ExplicitPayerId, T> {
/// Builds an unsigned [`InvoiceRequest`] after checking for valid semantics. It can be signed
/// by [`UnsignedInvoiceRequest::sign`].
pub fn build(self) -> Result<UnsignedInvoiceRequest<'a>, Bolt12SemanticError> {
pub fn build(self) -> Result<UnsignedInvoiceRequest, Bolt12SemanticError> {
let (unsigned_invoice_request, keys, _) = self.build_with_checks()?;
debug_assert!(keys.is_none());
Ok(unsigned_invoice_request)
@ -306,7 +307,9 @@ impl<'a, 'b, T: secp256k1::Signing> InvoiceRequestBuilder<'a, 'b, DerivedPayerId
let secp_ctx = secp_ctx.unwrap();
let keys = keys.unwrap();
let invoice_request = unsigned_invoice_request
.sign::<_, Infallible>(|digest| Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &keys)))
.sign::<_, Infallible>(
|message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
)
.unwrap();
Ok(invoice_request)
}
@ -335,52 +338,65 @@ impl<'a, 'b, P: PayerIdStrategy, T: secp256k1::Signing> InvoiceRequestBuilder<'a
self
}
pub(super) fn build_unchecked(self) -> UnsignedInvoiceRequest<'a> {
pub(super) fn build_unchecked(self) -> UnsignedInvoiceRequest {
self.build_without_checks().0
}
}
/// A semantically valid [`InvoiceRequest`] that hasn't been signed.
pub struct UnsignedInvoiceRequest<'a> {
offer: &'a Offer,
pub struct UnsignedInvoiceRequest {
bytes: Vec<u8>,
invoice_request: InvoiceRequestContents,
tagged_hash: TaggedHash,
}
impl<'a> UnsignedInvoiceRequest<'a> {
/// Signs the invoice request using the given function.
///
/// This is not exported to bindings users as functions are not yet mapped.
pub fn sign<F, E>(self, sign: F) -> Result<InvoiceRequest, SignError<E>>
where
F: FnOnce(&Message) -> Result<Signature, E>
{
impl UnsignedInvoiceRequest {
fn new(offer: &Offer, invoice_request: InvoiceRequestContents) -> Self {
// Use the offer bytes instead of the offer TLV stream as the offer may have contained
// unknown TLV records, which are not stored in `OfferContents`.
let (payer_tlv_stream, _offer_tlv_stream, invoice_request_tlv_stream) =
self.invoice_request.as_tlv_stream();
let offer_bytes = WithoutLength(&self.offer.bytes);
invoice_request.as_tlv_stream();
let offer_bytes = WithoutLength(&offer.bytes);
let unsigned_tlv_stream = (payer_tlv_stream, offer_bytes, invoice_request_tlv_stream);
let mut bytes = Vec::new();
unsigned_tlv_stream.write(&mut bytes).unwrap();
let tagged_hash = TaggedHash::new(SIGNATURE_TAG, &bytes);
Self { bytes, invoice_request, tagged_hash }
}
/// Signs the invoice request using the given function.
///
/// This is not exported to bindings users as functions are not yet mapped.
pub fn sign<F, E>(mut self, sign: F) -> Result<InvoiceRequest, SignError<E>>
where
F: FnOnce(&Self) -> Result<Signature, E>
{
let pubkey = self.invoice_request.payer_id;
let signature = merkle::sign_message(sign, SIGNATURE_TAG, &bytes, pubkey)?;
let signature = merkle::sign_message(sign, &self, pubkey)?;
// Append the signature TLV record to the bytes.
let signature_tlv_stream = SignatureTlvStreamRef {
signature: Some(&signature),
};
signature_tlv_stream.write(&mut bytes).unwrap();
signature_tlv_stream.write(&mut self.bytes).unwrap();
Ok(InvoiceRequest {
bytes,
bytes: self.bytes,
contents: self.invoice_request,
signature,
})
}
}
impl AsRef<TaggedHash> for UnsignedInvoiceRequest {
fn as_ref(&self) -> &TaggedHash {
&self.tagged_hash
}
}
/// An `InvoiceRequest` is a request for a [`Bolt12Invoice`] formulated from an [`Offer`].
///
/// An offer may provide choices such as quantity, amount, chain, features, etc. An invoice request
@ -591,7 +607,7 @@ impl InvoiceRequest {
}
impl InvoiceRequestContents {
pub fn metadata(&self) -> &[u8] {
pub(super) fn metadata(&self) -> &[u8] {
self.inner.metadata()
}
@ -790,7 +806,7 @@ mod tests {
use crate::ln::inbound_payment::ExpandedKey;
use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
use crate::offers::invoice::{Bolt12Invoice, SIGNATURE_TAG as INVOICE_SIGNATURE_TAG};
use crate::offers::merkle::{SignError, SignatureTlvStreamRef, self};
use crate::offers::merkle::{SignError, SignatureTlvStreamRef, TaggedHash, self};
use crate::offers::offer::{Amount, OfferBuilder, OfferTlvStreamRef, Quantity};
use crate::offers::parse::{Bolt12ParseError, Bolt12SemanticError};
use crate::offers::payer::PayerTlvStreamRef;
@ -922,9 +938,8 @@ mod tests {
let mut bytes = Vec::new();
tlv_stream.write(&mut bytes).unwrap();
let signature = merkle::sign_message(
recipient_sign, INVOICE_SIGNATURE_TAG, &bytes, recipient_pubkey()
).unwrap();
let message = TaggedHash::new(INVOICE_SIGNATURE_TAG, &bytes);
let signature = merkle::sign_message(recipient_sign, &message, recipient_pubkey()).unwrap();
signature_tlv_stream.signature = Some(&signature);
let mut encoded_invoice = bytes;
@ -946,9 +961,8 @@ mod tests {
let mut bytes = Vec::new();
tlv_stream.write(&mut bytes).unwrap();
let signature = merkle::sign_message(
recipient_sign, INVOICE_SIGNATURE_TAG, &bytes, recipient_pubkey()
).unwrap();
let message = TaggedHash::new(INVOICE_SIGNATURE_TAG, &bytes);
let signature = merkle::sign_message(recipient_sign, &message, recipient_pubkey()).unwrap();
signature_tlv_stream.signature = Some(&signature);
let mut encoded_invoice = bytes;
@ -992,9 +1006,8 @@ mod tests {
let mut bytes = Vec::new();
tlv_stream.write(&mut bytes).unwrap();
let signature = merkle::sign_message(
recipient_sign, INVOICE_SIGNATURE_TAG, &bytes, recipient_pubkey()
).unwrap();
let message = TaggedHash::new(INVOICE_SIGNATURE_TAG, &bytes);
let signature = merkle::sign_message(recipient_sign, &message, recipient_pubkey()).unwrap();
signature_tlv_stream.signature = Some(&signature);
let mut encoded_invoice = bytes;
@ -1016,9 +1029,8 @@ mod tests {
let mut bytes = Vec::new();
tlv_stream.write(&mut bytes).unwrap();
let signature = merkle::sign_message(
recipient_sign, INVOICE_SIGNATURE_TAG, &bytes, recipient_pubkey()
).unwrap();
let message = TaggedHash::new(INVOICE_SIGNATURE_TAG, &bytes);
let signature = merkle::sign_message(recipient_sign, &message, recipient_pubkey()).unwrap();
signature_tlv_stream.signature = Some(&signature);
let mut encoded_invoice = bytes;
@ -1771,7 +1783,9 @@ mod tests {
.build().unwrap()
.request_invoice(vec![1; 32], keys.public_key()).unwrap()
.build().unwrap()
.sign::<_, Infallible>(|digest| Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &keys)))
.sign::<_, Infallible>(
|message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
)
.unwrap();
let mut encoded_invoice_request = Vec::new();

68
lightning/src/offers/merkle.rs
View file

@ -12,6 +12,7 @@
use bitcoin::hashes::{Hash, HashEngine, sha256};
use bitcoin::secp256k1::{Message, PublicKey, Secp256k1, self};
use bitcoin::secp256k1::schnorr::Signature;
use core::convert::AsRef;
use crate::io;
use crate::util::ser::{BigSize, Readable, Writeable, Writer};
@ -24,6 +25,33 @@ tlv_stream!(SignatureTlvStream, SignatureTlvStreamRef, SIGNATURE_TYPES, {
(240, signature: Signature),
});
/// A hash for use in a specific context by tweaking with a context-dependent tag as per [BIP 340]
/// and computed over the merkle root of a TLV stream to sign as defined in [BOLT 12].
///
/// [BIP 340]: https://github.com/bitcoin/bips/blob/master/bip-0340.mediawiki
/// [BOLT 12]: https://github.com/rustyrussell/lightning-rfc/blob/guilt/offers/12-offer-encoding.md#signature-calculation
pub struct TaggedHash(Message);
impl TaggedHash {
/// Creates a tagged hash with the given parameters.
///
/// Panics if `tlv_stream` is not a well-formed TLV stream containing at least one TLV record.
pub(super) fn new(tag: &str, tlv_stream: &[u8]) -> Self {
Self(message_digest(tag, tlv_stream))
}
/// Returns the digest to sign.
pub fn as_digest(&self) -> &Message {
&self.0
}
}
impl AsRef<TaggedHash> for TaggedHash {
fn as_ref(&self) -> &TaggedHash {
self
}
}
/// Error when signing messages.
#[derive(Debug, PartialEq)]
pub enum SignError<E> {
@ -33,22 +61,28 @@ pub enum SignError<E> {
Verification(secp256k1::Error),
}
/// Signs a message digest consisting of a tagged hash of the given bytes, checking if it can be
/// verified with the supplied pubkey.
/// Signs a [`TaggedHash`] computed over the merkle root of `message`'s TLV stream, checking if it
/// can be verified with the supplied `pubkey`.
///
/// Panics if `bytes` is not a well-formed TLV stream containing at least one TLV record.
pub(super) fn sign_message<F, E>(
sign: F, tag: &str, bytes: &[u8], pubkey: PublicKey,
/// Since `message` is any type that implements [`AsRef<TaggedHash>`], `sign` may be a closure that
/// takes a message such as [`Bolt12Invoice`] or [`InvoiceRequest`]. This allows further message
/// verification before signing its [`TaggedHash`].
///
/// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
pub(super) fn sign_message<F, E, T>(
sign: F, message: &T, pubkey: PublicKey,
) -> Result<Signature, SignError<E>>
where
F: FnOnce(&Message) -> Result<Signature, E>
F: FnOnce(&T) -> Result<Signature, E>,
T: AsRef<TaggedHash>,
{
let digest = message_digest(tag, bytes);
let signature = sign(&digest).map_err(|e| SignError::Signing(e))?;
let signature = sign(message).map_err(|e| SignError::Signing(e))?;
let digest = message.as_ref().as_digest();
let pubkey = pubkey.into();
let secp_ctx = Secp256k1::verification_only();
secp_ctx.verify_schnorr(&signature, &digest, &pubkey).map_err(|e| SignError::Verification(e))?;
secp_ctx.verify_schnorr(&signature, digest, &pubkey).map_err(|e| SignError::Verification(e))?;
Ok(signature)
}
@ -207,12 +241,12 @@ impl<'a> Iterator for TlvStream<'a> {
/// Encoding for a pre-serialized TLV stream that excludes any signature TLV records.
///
/// Panics if the wrapped bytes are not a well-formed TLV stream.
pub(super) struct WithoutSignatures<'a>(pub &'a Vec<u8>);
pub(super) struct WithoutSignatures<'a>(pub &'a [u8]);
impl<'a> Writeable for WithoutSignatures<'a> {
#[inline]
fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
let tlv_stream = TlvStream::new(&self.0[..]);
let tlv_stream = TlvStream::new(self.0);
for record in tlv_stream.skip_signatures() {
writer.write_all(record.record_bytes)?;
}
@ -271,7 +305,9 @@ mod tests {
.build_unchecked()
.request_invoice(vec![0; 8], payer_keys.public_key()).unwrap()
.build_unchecked()
.sign::<_, Infallible>(|digest| Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &payer_keys)))
.sign::<_, Infallible>(
|message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &payer_keys))
)
.unwrap();
assert_eq!(
invoice_request.to_string(),
@ -304,7 +340,9 @@ mod tests {
.build_unchecked()
.request_invoice(vec![0; 8], payer_keys.public_key()).unwrap()
.build_unchecked()
.sign::<_, Infallible>(|digest| Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &payer_keys)))
.sign::<_, Infallible>(
|message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &payer_keys))
)
.unwrap();
let mut bytes_without_signature = Vec::new();
@ -334,7 +372,9 @@ mod tests {
.build_unchecked()
.request_invoice(vec![0; 8], payer_keys.public_key()).unwrap()
.build_unchecked()
.sign::<_, Infallible>(|digest| Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &payer_keys)))
.sign::<_, Infallible>(
|message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &payer_keys))
)
.unwrap();
let tlv_stream = TlvStream::new(&invoice_request.bytes).range(0..1)

13
lightning/src/offers/test_utils.rs
View file

@ -9,25 +9,26 @@
//! Utilities for testing BOLT 12 Offers interfaces
use bitcoin::secp256k1::{KeyPair, Message, PublicKey, Secp256k1, SecretKey};
use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
use bitcoin::secp256k1::schnorr::Signature;
use core::convert::Infallible;
use core::convert::{AsRef, Infallible};
use core::time::Duration;
use crate::blinded_path::{BlindedHop, BlindedPath};
use crate::sign::EntropySource;
use crate::ln::PaymentHash;
use crate::ln::features::BlindedHopFeatures;
use crate::offers::invoice::BlindedPayInfo;
use crate::offers::merkle::TaggedHash;
pub(super) fn payer_keys() -> KeyPair {
let secp_ctx = Secp256k1::new();
KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap())
}
pub(super) fn payer_sign(digest: &Message) -> Result<Signature, Infallible> {
pub(super) fn payer_sign<T: AsRef<TaggedHash>>(message: &T) -> Result<Signature, Infallible> {
let secp_ctx = Secp256k1::new();
let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &keys))
Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
}
pub(super) fn payer_pubkey() -> PublicKey {
@ -39,10 +40,10 @@ pub(super) fn recipient_keys() -> KeyPair {
KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[43; 32]).unwrap())
}
pub(super) fn recipient_sign(digest: &Message) -> Result<Signature, Infallible> {
pub(super) fn recipient_sign<T: AsRef<TaggedHash>>(message: &T) -> Result<Signature, Infallible> {
let secp_ctx = Secp256k1::new();
let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[43; 32]).unwrap());
Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &keys))
Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
}
pub(super) fn recipient_pubkey() -> PublicKey {