X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fchain%2Fkeysinterface.rs;h=9fc00e25238dc8b375d247aec5c8114ce508f109;hb=abf4e79dcda4c97dd80dd00233de32507184543a;hp=58abe7e9ddcb2dcf71ce26ec9ddd9d1824bb2f47;hpb=f0c181e2f26ddd0853884ea652933dc3bcc22181;p=rust-lightning

diff --git a/lightning/src/chain/keysinterface.rs b/lightning/src/chain/keysinterface.rs
index 58abe7e9..9fc00e25 100644
--- a/lightning/src/chain/keysinterface.rs
+++ b/lightning/src/chain/keysinterface.rs
@@ -137,7 +137,7 @@ impl_writeable_tlv_based!(StaticPaymentOutputDescriptor, {
 /// [`SpendableOutputs`]: crate::util::events::Event::SpendableOutputs
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub enum SpendableOutputDescriptor {
-	/// An output to a script which was provided via [`KeysInterface`] directly, either from
+	/// An output to a script which was provided via [`SignerProvider`] directly, either from
 	/// [`get_destination_script`] or [`get_shutdown_scriptpubkey`], thus you should already
 	/// know how to spend it. No secret keys are provided as LDK was never given any key.
 	/// These may include outputs from a transaction punishing our counterparty or claiming an HTLC
@@ -517,7 +517,7 @@ pub trait SignerProvider {
 	/// [`BaseSign::channel_keys_id`].
 	fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer;
 
-	/// Reads a [`Signer`] for this [`KeysInterface`] from the given input stream.
+	/// Reads a [`Signer`] for this [`SignerProvider`] from the given input stream.
 	/// This is only called during deserialization of other objects which contain
 	/// [`Sign`]-implementing objects (i.e., [`ChannelMonitor`]s and [`ChannelManager`]s).
 	/// The bytes are exactly those which `<Self::Signer as Writeable>::write()` writes, and
@@ -545,9 +545,6 @@ pub trait SignerProvider {
 	fn get_shutdown_scriptpubkey(&self) -> ShutdownScript;
 }
 
-/// A trait to describe an object which can get user secrets and key material.
-pub trait KeysInterface: EntropySource + NodeSigner + SignerProvider {}
-
 #[derive(Clone)]
 /// A simple implementation of [`Sign`] that just keeps the private keys in memory.
 ///
@@ -954,8 +951,8 @@ impl ReadableArgs<SecretKey> for InMemorySigner {
 	}
 }
 
-/// Simple [`KeysInterface`] implementation that takes a 32-byte seed for use as a BIP 32 extended
-/// key and derives keys from that.
+/// Simple implementation of [`EntropySource`], [`NodeSigner`], and [`SignerProvider`] that takes a
+/// 32-byte seed for use as a BIP 32 extended key and derives keys from that.
 ///
 /// Your `node_id` is seed/0'.
 /// Unilateral closes may use seed/1'.
@@ -1072,7 +1069,9 @@ impl KeysManager {
 		// We only seriously intend to rely on the channel_master_key for true secure
 		// entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
 		// starting_time provided in the constructor) to be unique.
-		let child_privkey = self.channel_master_key.ckd_priv(&self.secp_ctx, ChildNumber::from_hardened_idx(chan_id as u32).expect("key space exhausted")).expect("Your RNG is busted");
+		let child_privkey = self.channel_master_key.ckd_priv(&self.secp_ctx,
+				ChildNumber::from_hardened_idx((chan_id as u32) % (1 << 31)).expect("key space exhausted")
+			).expect("Your RNG is busted");
 		unique_start.input(&child_privkey.private_key[..]);
 
 		let seed = Sha256::from_engine(unique_start).into_inner();
@@ -1298,7 +1297,12 @@ impl SignerProvider for KeysManager {
 
 	fn generate_channel_keys_id(&self, _inbound: bool, _channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32] {
 		let child_idx = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
-		assert!(child_idx <= core::u32::MAX as usize);
+		// `child_idx` is the only thing guaranteed to make each channel unique without a restart
+		// (though `user_channel_id` should help, depending on user behavior). If it manages to
+		// roll over, we may generate duplicate keys for two different channels, which could result
+		// in loss of funds. Because we only support 32-bit+ systems, assert that our `AtomicUsize`
+		// doesn't reach `u32::MAX`.
+		assert!(child_idx < core::u32::MAX as usize, "2^32 channels opened without restart");
 		let mut id = [0; 32];
 		id[0..4].copy_from_slice(&(child_idx as u32).to_be_bytes());
 		id[4..8].copy_from_slice(&self.starting_time_nanos.to_be_bytes());
@@ -1324,8 +1328,6 @@ impl SignerProvider for KeysManager {
 	}
 }
 
-impl KeysInterface for KeysManager {}
-
 /// Similar to [`KeysManager`], but allows the node using this struct to receive phantom node
 /// payments.
 ///
@@ -1418,8 +1420,6 @@ impl SignerProvider for PhantomKeysManager {
 	}
 }
 
-impl KeysInterface for PhantomKeysManager {}
-
 impl PhantomKeysManager {
 	/// Constructs a [`PhantomKeysManager`] given a 32-byte seed and an additional `cross_node_seed`
 	/// that is shared across all nodes that intend to participate in [phantom node payments]