Merge pull request #2111 from TheBlueMatt/2023-03-sent-persist-order-prep
[rust-lightning] / lightning / src / ln / inbound_payment.rs
index 0c6d6f2b804bccd8cfb651c24995bf4959998a91..1b0fd1707b8c664fd0b37cbc25bad67ef0704085 100644 (file)
@@ -14,19 +14,19 @@ use bitcoin::hashes::{Hash, HashEngine};
 use bitcoin::hashes::cmp::fixed_time_eq;
 use bitcoin::hashes::hmac::{Hmac, HmacEngine};
 use bitcoin::hashes::sha256::Hash as Sha256;
-use crate::chain::keysinterface::{KeyMaterial, EntropySource};
+use crate::sign::{KeyMaterial, EntropySource};
 use crate::ln::{PaymentHash, PaymentPreimage, PaymentSecret};
 use crate::ln::msgs;
 use crate::ln::msgs::MAX_VALUE_MSAT;
 use crate::util::chacha20::ChaCha20;
-use crate::util::crypto::hkdf_extract_expand_thrice;
+use crate::util::crypto::hkdf_extract_expand_4x;
 use crate::util::errors::APIError;
 use crate::util::logger::Logger;
 
-use core::convert::TryInto;
+use core::convert::{TryFrom, TryInto};
 use core::ops::Deref;
 
-const IV_LEN: usize = 16;
+pub(crate) const IV_LEN: usize = 16;
 const METADATA_LEN: usize = 16;
 const METADATA_KEY_LEN: usize = 32;
 const AMT_MSAT_LEN: usize = 8;
@@ -37,7 +37,7 @@ const METHOD_TYPE_OFFSET: usize = 5;
 /// A set of keys that were HKDF-expanded from an initial call to
 /// [`NodeSigner::get_inbound_payment_key_material`].
 ///
-/// [`NodeSigner::get_inbound_payment_key_material`]: crate::chain::keysinterface::NodeSigner::get_inbound_payment_key_material
+/// [`NodeSigner::get_inbound_payment_key_material`]: crate::sign::NodeSigner::get_inbound_payment_key_material
 pub struct ExpandedKey {
        /// The key used to encrypt the bytes containing the payment metadata (i.e. the amount and
        /// expiry, included for payment verification on decryption).
@@ -48,6 +48,8 @@ pub struct ExpandedKey {
        /// The key used to authenticate a user-provided payment hash and metadata as previously
        /// registered with LDK.
        user_pmt_hash_key: [u8; 32],
+       /// The base key used to derive signing keys and authenticate messages for BOLT 12 Offers.
+       offers_base_key: [u8; 32],
 }
 
 impl ExpandedKey {
@@ -55,14 +57,76 @@ impl ExpandedKey {
        ///
        /// It is recommended to cache this value and not regenerate it for each new inbound payment.
        pub fn new(key_material: &KeyMaterial) -> ExpandedKey {
-               let (metadata_key, ldk_pmt_hash_key, user_pmt_hash_key) =
-                       hkdf_extract_expand_thrice(b"LDK Inbound Payment Key Expansion", &key_material.0);
+               let (metadata_key, ldk_pmt_hash_key, user_pmt_hash_key, offers_base_key) =
+                       hkdf_extract_expand_4x(b"LDK Inbound Payment Key Expansion", &key_material.0);
                Self {
                        metadata_key,
                        ldk_pmt_hash_key,
                        user_pmt_hash_key,
+                       offers_base_key,
                }
        }
+
+       /// Returns an [`HmacEngine`] used to construct [`Offer::metadata`].
+       ///
+       /// [`Offer::metadata`]: crate::offers::offer::Offer::metadata
+       #[allow(unused)]
+       pub(crate) fn hmac_for_offer(
+               &self, nonce: Nonce, iv_bytes: &[u8; IV_LEN]
+       ) -> HmacEngine<Sha256> {
+               let mut hmac = HmacEngine::<Sha256>::new(&self.offers_base_key);
+               hmac.input(iv_bytes);
+               hmac.input(&nonce.0);
+               hmac
+       }
+}
+
+/// A 128-bit number used only once.
+///
+/// Needed when constructing [`Offer::metadata`] and deriving [`Offer::signing_pubkey`] from
+/// [`ExpandedKey`]. Must not be reused for any other derivation without first hashing.
+///
+/// [`Offer::metadata`]: crate::offers::offer::Offer::metadata
+/// [`Offer::signing_pubkey`]: crate::offers::offer::Offer::signing_pubkey
+#[allow(unused)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub(crate) struct Nonce(pub(crate) [u8; Self::LENGTH]);
+
+impl Nonce {
+       /// Number of bytes in the nonce.
+       pub const LENGTH: usize = 16;
+
+       /// Creates a `Nonce` from the given [`EntropySource`].
+       pub fn from_entropy_source<ES: Deref>(entropy_source: ES) -> Self
+       where
+               ES::Target: EntropySource,
+       {
+               let mut bytes = [0u8; Self::LENGTH];
+               let rand_bytes = entropy_source.get_secure_random_bytes();
+               bytes.copy_from_slice(&rand_bytes[..Self::LENGTH]);
+
+               Nonce(bytes)
+       }
+
+       /// Returns a slice of the underlying bytes of size [`Nonce::LENGTH`].
+       pub fn as_slice(&self) -> &[u8] {
+               &self.0
+       }
+}
+
+impl TryFrom<&[u8]> for Nonce {
+       type Error = ();
+
+       fn try_from(bytes: &[u8]) -> Result<Self, ()> {
+               if bytes.len() != Self::LENGTH {
+                       return Err(());
+               }
+
+               let mut copied_bytes = [0u8; Self::LENGTH];
+               copied_bytes.copy_from_slice(bytes);
+
+               Ok(Self(copied_bytes))
+       }
 }
 
 enum Method {
@@ -102,8 +166,8 @@ fn min_final_cltv_expiry_delta_from_metadata(bytes: [u8; METADATA_LEN]) -> u16 {
 /// Note that if `min_final_cltv_expiry_delta` is set to some value, then the payment will not be receivable
 /// on versions of LDK prior to 0.0.114.
 ///
-/// [phantom node payments]: crate::chain::keysinterface::PhantomKeysManager
-/// [`NodeSigner::get_inbound_payment_key_material`]: crate::chain::keysinterface::NodeSigner::get_inbound_payment_key_material
+/// [phantom node payments]: crate::sign::PhantomKeysManager
+/// [`NodeSigner::get_inbound_payment_key_material`]: crate::sign::NodeSigner::get_inbound_payment_key_material
 pub fn create<ES: Deref>(keys: &ExpandedKey, min_value_msat: Option<u64>,
        invoice_expiry_delta_secs: u32, entropy_source: &ES, current_time: u64,
        min_final_cltv_expiry_delta: Option<u16>) -> Result<(PaymentHash, PaymentSecret), ()>
@@ -138,7 +202,7 @@ pub fn create<ES: Deref>(keys: &ExpandedKey, min_value_msat: Option<u64>,
 /// Note that if `min_final_cltv_expiry_delta` is set to some value, then the payment will not be receivable
 /// on versions of LDK prior to 0.0.114.
 ///
-/// [phantom node payments]: crate::chain::keysinterface::PhantomKeysManager
+/// [phantom node payments]: crate::sign::PhantomKeysManager
 pub fn create_from_hash(keys: &ExpandedKey, min_value_msat: Option<u64>, payment_hash: PaymentHash,
        invoice_expiry_delta_secs: u32, current_time: u64, min_final_cltv_expiry_delta: Option<u16>) -> Result<PaymentSecret, ()> {
        let metadata_bytes = construct_metadata_bytes(min_value_msat, if min_final_cltv_expiry_delta.is_some() {
@@ -247,7 +311,7 @@ fn construct_payment_secret(iv_bytes: &[u8; IV_LEN], metadata_bytes: &[u8; METAD
 ///
 /// See [`ExpandedKey`] docs for more info on the individual keys used.
 ///
-/// [`NodeSigner::get_inbound_payment_key_material`]: crate::chain::keysinterface::NodeSigner::get_inbound_payment_key_material
+/// [`NodeSigner::get_inbound_payment_key_material`]: crate::sign::NodeSigner::get_inbound_payment_key_material
 /// [`create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
 /// [`create_inbound_payment_for_hash`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment_for_hash
 pub(super) fn verify<L: Deref>(payment_hash: PaymentHash, payment_data: &msgs::FinalOnionHopData,