X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fblinded_path%2Fmod.rs;h=b1fc9e1c0a443c36cbb5d3a772ac944a869d7268;hb=7c9463668a4f71663746e57bdb09ee6b91797d5a;hp=2cd03b8b8f90e9fc1cd2068c61d4ce3cb8506ddf;hpb=ec3aa494953c7d720370119f673e8e6b3a2155d5;p=rust-lightning diff --git a/lightning/src/blinded_path/mod.rs b/lightning/src/blinded_path/mod.rs index 2cd03b8b..b1fc9e1c 100644 --- a/lightning/src/blinded_path/mod.rs +++ b/lightning/src/blinded_path/mod.rs @@ -9,22 +9,18 @@ //! Creating blinded paths and related utilities live here. +pub mod payment; +pub(crate) mod message; pub(crate) mod utils; -use bitcoin::hashes::{Hash, HashEngine}; -use bitcoin::hashes::sha256::Hash as Sha256; -use bitcoin::secp256k1::{self, PublicKey, Scalar, Secp256k1, SecretKey}; +use bitcoin::secp256k1::{self, PublicKey, Secp256k1, SecretKey}; -use crate::chain::keysinterface::{EntropySource, NodeSigner, Recipient}; -use crate::onion_message::ControlTlvs; use crate::ln::msgs::DecodeError; -use crate::ln::onion_utils; -use crate::util::chacha20poly1305rfc::{ChaChaPolyReadAdapter, ChaChaPolyWriteAdapter}; -use crate::util::ser::{FixedLengthReader, LengthReadableArgs, Readable, VecWriter, Writeable, Writer}; +use crate::offers::invoice::BlindedPayInfo; +use crate::sign::EntropySource; +use crate::util::ser::{Readable, Writeable, Writer}; -use core::mem; -use core::ops::Deref; -use crate::io::{self, Cursor}; +use crate::io; use crate::prelude::*; /// Onion messages and payments can be sent and received to blinded paths, which serve to hide the @@ -36,38 +32,46 @@ pub struct BlindedPath { /// message or payment's next hop and forward it along. /// /// [`encrypted_payload`]: BlindedHop::encrypted_payload - pub(crate) introduction_node_id: PublicKey, + pub introduction_node_id: PublicKey, /// Used by the introduction node to decrypt its [`encrypted_payload`] to forward the onion /// message or payment. /// /// [`encrypted_payload`]: BlindedHop::encrypted_payload - pub(crate) blinding_point: PublicKey, + pub blinding_point: PublicKey, /// The hops composing the blinded path. - pub(crate) blinded_hops: Vec, + pub blinded_hops: Vec, } -/// Used to construct the blinded hops portion of a blinded path. These hops cannot be identified -/// by outside observers and thus can be used to hide the identity of the recipient. +/// An encrypted payload and node id corresponding to a hop in a payment or onion message path, to +/// be encoded in the sender's onion packet. These hops cannot be identified by outside observers +/// and thus can be used to hide the identity of the recipient. #[derive(Clone, Debug, Hash, PartialEq, Eq)] pub struct BlindedHop { - /// The blinded node id of this hop in a blinded path. - pub(crate) blinded_node_id: PublicKey, - /// The encrypted payload intended for this hop in a blinded path. + /// The blinded node id of this hop in a [`BlindedPath`]. + pub blinded_node_id: PublicKey, + /// The encrypted payload intended for this hop in a [`BlindedPath`]. // The node sending to this blinded path will later encode this payload into the onion packet for // this hop. - pub(crate) encrypted_payload: Vec, + pub encrypted_payload: Vec, } impl BlindedPath { + /// Create a one-hop blinded path for a message. + pub fn one_hop_for_message( + recipient_node_id: PublicKey, entropy_source: &ES, secp_ctx: &Secp256k1 + ) -> Result { + Self::new_for_message(&[recipient_node_id], entropy_source, secp_ctx) + } + /// Create a blinded path for an onion message, to be forwarded along `node_pks`. The last node /// pubkey in `node_pks` will be the destination node. /// - /// Errors if less than two hops are provided or if `node_pk`(s) are invalid. + /// Errors if no hops are provided or if `node_pk`(s) are invalid. // TODO: make all payloads the same size with padding + add dummy hops - pub fn new_for_message - (node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1) -> Result - { - if node_pks.len() < 2 { return Err(()) } + pub fn new_for_message( + node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1 + ) -> Result { + if node_pks.is_empty() { return Err(()) } let blinding_secret_bytes = entropy_source.get_secure_random_bytes(); let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted"); let introduction_node_id = node_pks[0]; @@ -75,87 +79,49 @@ impl BlindedPath { Ok(BlindedPath { introduction_node_id, blinding_point: PublicKey::from_secret_key(secp_ctx, &blinding_secret), - blinded_hops: blinded_message_hops(secp_ctx, node_pks, &blinding_secret).map_err(|_| ())?, + blinded_hops: message::blinded_hops(secp_ctx, node_pks, &blinding_secret).map_err(|_| ())?, }) } - // Advance the blinded onion message path by one hop, so make the second hop into the new - // introduction node. - pub(super) fn advance_message_path_by_one - (&mut self, node_signer: &NS, secp_ctx: &Secp256k1) -> Result<(), ()> - where NS::Target: NodeSigner - { - let control_tlvs_ss = node_signer.ecdh(Recipient::Node, &self.blinding_point, None)?; - let rho = onion_utils::gen_rho_from_shared_secret(&control_tlvs_ss.secret_bytes()); - let encrypted_control_tlvs = self.blinded_hops.remove(0).encrypted_payload; - let mut s = Cursor::new(&encrypted_control_tlvs); - let mut reader = FixedLengthReader::new(&mut s, encrypted_control_tlvs.len() as u64); - match ChaChaPolyReadAdapter::read(&mut reader, rho) { - Ok(ChaChaPolyReadAdapter { readable: ControlTlvs::Forward(ForwardTlvs { - mut next_node_id, next_blinding_override, - })}) => { - let mut new_blinding_point = match next_blinding_override { - Some(blinding_point) => blinding_point, - None => { - let blinding_factor = { - let mut sha = Sha256::engine(); - sha.input(&self.blinding_point.serialize()[..]); - sha.input(control_tlvs_ss.as_ref()); - Sha256::from_engine(sha).into_inner() - }; - self.blinding_point.mul_tweak(secp_ctx, &Scalar::from_be_bytes(blinding_factor).unwrap()) - .map_err(|_| ())? - } - }; - mem::swap(&mut self.blinding_point, &mut new_blinding_point); - mem::swap(&mut self.introduction_node_id, &mut next_node_id); - Ok(()) - }, - _ => Err(()) - } + /// Create a one-hop blinded path for a payment. + pub fn one_hop_for_payment( + payee_node_id: PublicKey, payee_tlvs: payment::ReceiveTlvs, entropy_source: &ES, + secp_ctx: &Secp256k1 + ) -> Result<(BlindedPayInfo, Self), ()> { + // This value is not considered in pathfinding for 1-hop blinded paths, because it's intended to + // be in relation to a specific channel. + let htlc_maximum_msat = u64::max_value(); + Self::new_for_payment( + &[], payee_node_id, payee_tlvs, htlc_maximum_msat, entropy_source, secp_ctx + ) } -} -/// Construct blinded onion message hops for the given `unblinded_path`. -fn blinded_message_hops( - secp_ctx: &Secp256k1, unblinded_path: &[PublicKey], session_priv: &SecretKey -) -> Result, secp256k1::Error> { - let mut blinded_hops = Vec::with_capacity(unblinded_path.len()); - - let mut prev_ss_and_blinded_node_id = None; - utils::construct_keys_callback(secp_ctx, unblinded_path, None, session_priv, |blinded_node_id, _, _, encrypted_payload_ss, unblinded_pk, _| { - if let Some((prev_ss, prev_blinded_node_id)) = prev_ss_and_blinded_node_id { - if let Some(pk) = unblinded_pk { - let payload = ForwardTlvs { - next_node_id: pk, - next_blinding_override: None, - }; - blinded_hops.push(BlindedHop { - blinded_node_id: prev_blinded_node_id, - encrypted_payload: encrypt_payload(payload, prev_ss), - }); - } else { debug_assert!(false); } - } - prev_ss_and_blinded_node_id = Some((encrypted_payload_ss, blinded_node_id)); - })?; - - if let Some((final_ss, final_blinded_node_id)) = prev_ss_and_blinded_node_id { - let final_payload = ReceiveTlvs { path_id: None }; - blinded_hops.push(BlindedHop { - blinded_node_id: final_blinded_node_id, - encrypted_payload: encrypt_payload(final_payload, final_ss), - }); - } else { debug_assert!(false) } - - Ok(blinded_hops) -} + /// Create a blinded path for a payment, to be forwarded along `intermediate_nodes`. + /// + /// Errors if: + /// * a provided node id is invalid + /// * [`BlindedPayInfo`] calculation results in an integer overflow + /// * any unknown features are required in the provided [`ForwardTlvs`] + /// + /// [`ForwardTlvs`]: crate::blinded_path::payment::ForwardTlvs + // TODO: make all payloads the same size with padding + add dummy hops + pub fn new_for_payment( + intermediate_nodes: &[payment::ForwardNode], payee_node_id: PublicKey, + payee_tlvs: payment::ReceiveTlvs, htlc_maximum_msat: u64, entropy_source: &ES, + secp_ctx: &Secp256k1 + ) -> Result<(BlindedPayInfo, Self), ()> { + let blinding_secret_bytes = entropy_source.get_secure_random_bytes(); + let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted"); -/// Encrypt TLV payload to be used as a [`BlindedHop::encrypted_payload`]. -fn encrypt_payload(payload: P, encrypted_tlvs_ss: [u8; 32]) -> Vec { - let mut writer = VecWriter(Vec::new()); - let write_adapter = ChaChaPolyWriteAdapter::new(encrypted_tlvs_ss, &payload); - write_adapter.write(&mut writer).expect("In-memory writes cannot fail"); - writer.0 + let blinded_payinfo = payment::compute_payinfo(intermediate_nodes, &payee_tlvs, htlc_maximum_msat)?; + Ok((blinded_payinfo, BlindedPath { + introduction_node_id: intermediate_nodes.first().map_or(payee_node_id, |n| n.node_id), + blinding_point: PublicKey::from_secret_key(secp_ctx, &blinding_secret), + blinded_hops: payment::blinded_hops( + secp_ctx, intermediate_nodes, payee_node_id, payee_tlvs, &blinding_secret + ).map_err(|_| ())?, + })) + } } impl Writeable for BlindedPath { @@ -193,41 +159,3 @@ impl_writeable!(BlindedHop, { encrypted_payload }); -/// TLVs to encode in an intermediate onion message packet's hop data. When provided in a blinded -/// route, they are encoded into [`BlindedHop::encrypted_payload`]. -pub(crate) struct ForwardTlvs { - /// The node id of the next hop in the onion message's path. - pub(super) next_node_id: PublicKey, - /// Senders to a blinded path use this value to concatenate the route they find to the - /// introduction node with the blinded path. - pub(super) next_blinding_override: Option, -} - -/// Similar to [`ForwardTlvs`], but these TLVs are for the final node. -pub(crate) struct ReceiveTlvs { - /// If `path_id` is `Some`, it is used to identify the blinded path that this onion message is - /// sending to. This is useful for receivers to check that said blinded path is being used in - /// the right context. - pub(super) path_id: Option<[u8; 32]>, -} - -impl Writeable for ForwardTlvs { - fn write(&self, writer: &mut W) -> Result<(), io::Error> { - // TODO: write padding - encode_tlv_stream!(writer, { - (4, self.next_node_id, required), - (8, self.next_blinding_override, option) - }); - Ok(()) - } -} - -impl Writeable for ReceiveTlvs { - fn write(&self, writer: &mut W) -> Result<(), io::Error> { - // TODO: write padding - encode_tlv_stream!(writer, { - (6, self.path_id, option), - }); - Ok(()) - } -}