_ Git - rust-lightning/blob - lightning/src/ln/peer_channel_encryptor.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
   5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
   7 // You may not use this file except in accordance with one or both of these
   8 // licenses.
   9
  10 use crate::prelude::*;
  11
  12 use crate::sign::{NodeSigner, Recipient};
  13 use crate::ln::msgs::LightningError;
  14 use crate::ln::msgs;
  15 use crate::ln::wire;
  16
  17 use bitcoin::hashes::{Hash, HashEngine};
  18 use bitcoin::hashes::sha256::Hash as Sha256;
  19
  20 use bitcoin::secp256k1::Secp256k1;
  21 use bitcoin::secp256k1::{PublicKey,SecretKey};
  22 use bitcoin::secp256k1::ecdh::SharedSecret;
  23 use bitcoin::secp256k1;
  24
  25 use crate::util::chacha20poly1305rfc::ChaCha20Poly1305RFC;
  26 use crate::util::crypto::hkdf_extract_expand_twice;
  27 use crate::util::ser::VecWriter;
  28 use bitcoin::hashes::hex::ToHex;
  29
  30 use core::ops::Deref;
  31
  32 /// Maximum Lightning message data length according to
  33 /// [BOLT-8](https://github.com/lightning/bolts/blob/v1.0/08-transport.md#lightning-message-specification)
  34 /// and [BOLT-1](https://github.com/lightning/bolts/blob/master/01-messaging.md#lightning-message-format):
  35 pub const LN_MAX_MSG_LEN: usize = ::core::u16::MAX as usize; // Must be equal to 65535
  36
  37 /// The (rough) size buffer to pre-allocate when encoding a message. Messages should reliably be
  38 /// smaller than this size by at least 32 bytes or so.
  39 pub const MSG_BUF_ALLOC_SIZE: usize = 2048;
  40
  41 // Sha256("Noise_XK_secp256k1_ChaChaPoly_SHA256")
  42 const NOISE_CK: [u8; 32] = [0x26, 0x40, 0xf5, 0x2e, 0xeb, 0xcd, 0x9e, 0x88, 0x29, 0x58, 0x95, 0x1c, 0x79, 0x42, 0x50, 0xee, 0xdb, 0x28, 0x00, 0x2c, 0x05, 0xd7, 0xdc, 0x2e, 0xa0, 0xf1, 0x95, 0x40, 0x60, 0x42, 0xca, 0xf1];
  43 // Sha256(NOISE_CK || "lightning")
  44 const NOISE_H: [u8; 32] = [0xd1, 0xfb, 0xf6, 0xde, 0xe4, 0xf6, 0x86, 0xf1, 0x32, 0xfd, 0x70, 0x2c, 0x4a, 0xbf, 0x8f, 0xba, 0x4b, 0xb4, 0x20, 0xd8, 0x9d, 0x2a, 0x04, 0x8a, 0x3c, 0x4f, 0x4c, 0x09, 0x2e, 0x37, 0xb6, 0x76];
  45
  46 enum NoiseSecretKey<'a, 'b, NS: Deref> where NS::Target: NodeSigner {
  47         InMemory(&'a SecretKey),
  48         NodeSigner(&'b NS)
  49 }
  50
  51 pub enum NextNoiseStep {
  52         ActOne,
  53         ActTwo,
  54         ActThree,
  55         NoiseComplete,
  56 }
  57
  58 #[derive(PartialEq)]
  59 enum NoiseStep {
  60         PreActOne,
  61         PostActOne,
  62         PostActTwo,
  63         // When done swap noise_state for NoiseState::Finished
  64 }
  65
  66 struct BidirectionalNoiseState {
  67         h: [u8; 32],
  68         ck: [u8; 32],
  69 }
  70 enum DirectionalNoiseState {
  71         Outbound {
  72                 ie: SecretKey,
  73         },
  74         Inbound {
  75                 ie: Option<PublicKey>, // filled in if state >= PostActOne
  76                 re: Option<SecretKey>, // filled in if state >= PostActTwo
  77                 temp_k2: Option<[u8; 32]>, // filled in if state >= PostActTwo
  78         }
  79 }
  80 enum NoiseState {
  81         InProgress {
  82                 state: NoiseStep,
  83                 directional_state: DirectionalNoiseState,
  84                 bidirectional_state: BidirectionalNoiseState,
  85         },
  86         Finished {
  87                 sk: [u8; 32],
  88                 sn: u64,
  89                 sck: [u8; 32],
  90                 rk: [u8; 32],
  91                 rn: u64,
  92                 rck: [u8; 32],
  93         }
  94 }
  95
  96 pub struct PeerChannelEncryptor {
  97         their_node_id: Option<PublicKey>, // filled in for outbound, or inbound after noise_state is Finished
  98
  99         noise_state: NoiseState,
 100 }
 101
 102 impl PeerChannelEncryptor {
 103         pub fn new_outbound(their_node_id: PublicKey, ephemeral_key: SecretKey) -> PeerChannelEncryptor {
 104                 let mut sha = Sha256::engine();
 105                 sha.input(&NOISE_H);
 106                 sha.input(&their_node_id.serialize()[..]);
 107                 let h = Sha256::from_engine(sha).into_inner();
 108
 109                 PeerChannelEncryptor {
 110                         their_node_id: Some(their_node_id),
 111                         noise_state: NoiseState::InProgress {
 112                                 state: NoiseStep::PreActOne,
 113                                 directional_state: DirectionalNoiseState::Outbound {
 114                                         ie: ephemeral_key,
 115                                 },
 116                                 bidirectional_state: BidirectionalNoiseState {
 117                                         h,
 118                                         ck: NOISE_CK,
 119                                 },
 120                         }
 121                 }
 122         }
 123
 124         pub fn new_inbound<NS: Deref>(node_signer: &NS) -> PeerChannelEncryptor where NS::Target: NodeSigner {
 125                 let mut sha = Sha256::engine();
 126                 sha.input(&NOISE_H);
 127                 let our_node_id = node_signer.get_node_id(Recipient::Node).unwrap();
 128                 sha.input(&our_node_id.serialize()[..]);
 129                 let h = Sha256::from_engine(sha).into_inner();
 130
 131                 PeerChannelEncryptor {
 132                         their_node_id: None,
 133                         noise_state: NoiseState::InProgress {
 134                                 state: NoiseStep::PreActOne,
 135                                 directional_state: DirectionalNoiseState::Inbound {
 136                                         ie: None,
 137                                         re: None,
 138                                         temp_k2: None,
 139                                 },
 140                                 bidirectional_state: BidirectionalNoiseState {
 141                                         h,
 142                                         ck: NOISE_CK,
 143                                 },
 144                         }
 145                 }
 146         }
 147
 148         #[inline]
 149         fn encrypt_with_ad(res: &mut[u8], n: u64, key: &[u8; 32], h: &[u8], plaintext: &[u8]) {
 150                 let mut nonce = [0; 12];
 151                 nonce[4..].copy_from_slice(&n.to_le_bytes()[..]);
 152
 153                 let mut chacha = ChaCha20Poly1305RFC::new(key, &nonce, h);
 154                 let mut tag = [0; 16];
 155                 chacha.encrypt(plaintext, &mut res[0..plaintext.len()], &mut tag);
 156                 res[plaintext.len()..].copy_from_slice(&tag);
 157         }
 158
 159         #[inline]
 160         /// Encrypts the message in res[offset..] in-place and pushes a 16-byte tag onto the end of
 161         /// res.
 162         fn encrypt_in_place_with_ad(res: &mut Vec<u8>, offset: usize, n: u64, key: &[u8; 32], h: &[u8]) {
 163                 let mut nonce = [0; 12];
 164                 nonce[4..].copy_from_slice(&n.to_le_bytes()[..]);
 165
 166                 let mut chacha = ChaCha20Poly1305RFC::new(key, &nonce, h);
 167                 let mut tag = [0; 16];
 168                 chacha.encrypt_full_message_in_place(&mut res[offset..], &mut tag);
 169                 res.extend_from_slice(&tag);
 170         }
 171
 172         fn decrypt_in_place_with_ad(inout: &mut [u8], n: u64, key: &[u8; 32], h: &[u8]) -> Result<(), LightningError> {
 173                 let mut nonce = [0; 12];
 174                 nonce[4..].copy_from_slice(&n.to_le_bytes()[..]);
 175
 176                 let mut chacha = ChaCha20Poly1305RFC::new(key, &nonce, h);
 177                 let (inout, tag) = inout.split_at_mut(inout.len() - 16);
 178                 if chacha.check_decrypt_in_place(inout, tag).is_err() {
 179                         return Err(LightningError{err: "Bad MAC".to_owned(), action: msgs::ErrorAction::DisconnectPeer{ msg: None }});
 180                 }
 181                 Ok(())
 182         }
 183
 184         #[inline]
 185         fn decrypt_with_ad(res: &mut[u8], n: u64, key: &[u8; 32], h: &[u8], cyphertext: &[u8]) -> Result<(), LightningError> {
 186                 let mut nonce = [0; 12];
 187                 nonce[4..].copy_from_slice(&n.to_le_bytes()[..]);
 188
 189                 let mut chacha = ChaCha20Poly1305RFC::new(key, &nonce, h);
 190                 if !chacha.decrypt(&cyphertext[0..cyphertext.len() - 16], res, &cyphertext[cyphertext.len() - 16..]) {
 191                         return Err(LightningError{err: "Bad MAC".to_owned(), action: msgs::ErrorAction::DisconnectPeer{ msg: None }});
 192                 }
 193                 Ok(())
 194         }
 195
 196         #[inline]
 197         fn hkdf(state: &mut BidirectionalNoiseState, ss: SharedSecret) -> [u8; 32] {
 198                 let (t1, t2) = hkdf_extract_expand_twice(&state.ck, ss.as_ref());
 199                 state.ck = t1;
 200                 t2
 201         }
 202
 203         #[inline]
 204         fn outbound_noise_act<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, state: &mut BidirectionalNoiseState, our_key: &SecretKey, their_key: &PublicKey) -> ([u8; 50], [u8; 32]) {
 205                 let our_pub = PublicKey::from_secret_key(secp_ctx, &our_key);
 206
 207                 let mut sha = Sha256::engine();
 208                 sha.input(&state.h);
 209                 sha.input(&our_pub.serialize()[..]);
 210                 state.h = Sha256::from_engine(sha).into_inner();
 211
 212                 let ss = SharedSecret::new(&their_key, &our_key);
 213                 let temp_k = PeerChannelEncryptor::hkdf(state, ss);
 214
 215                 let mut res = [0; 50];
 216                 res[1..34].copy_from_slice(&our_pub.serialize()[..]);
 217                 PeerChannelEncryptor::encrypt_with_ad(&mut res[34..], 0, &temp_k, &state.h, &[0; 0]);
 218
 219                 let mut sha = Sha256::engine();
 220                 sha.input(&state.h);
 221                 sha.input(&res[34..]);
 222                 state.h = Sha256::from_engine(sha).into_inner();
 223
 224                 (res, temp_k)
 225         }
 226
 227         #[inline]
 228         fn inbound_noise_act<'a, 'b, NS: Deref>(
 229                 state: &mut BidirectionalNoiseState, act: &[u8], secret_key: NoiseSecretKey<'a, 'b, NS>
 230         ) -> Result<(PublicKey, [u8; 32]), LightningError> where NS::Target: NodeSigner {
 231                 assert_eq!(act.len(), 50);
 232
 233                 if act[0] != 0 {
 234                         return Err(LightningError{err: format!("Unknown handshake version number {}", act[0]), action: msgs::ErrorAction::DisconnectPeer{ msg: None }});
 235                 }
 236
 237                 let their_pub = match PublicKey::from_slice(&act[1..34]) {
 238                         Err(_) => return Err(LightningError{err: format!("Invalid public key {}", &act[1..34].to_hex()), action: msgs::ErrorAction::DisconnectPeer{ msg: None }}),
 239                         Ok(key) => key,
 240                 };
 241
 242                 let mut sha = Sha256::engine();
 243                 sha.input(&state.h);
 244                 sha.input(&their_pub.serialize()[..]);
 245                 state.h = Sha256::from_engine(sha).into_inner();
 246
 247                 let ss = match secret_key {
 248                         NoiseSecretKey::InMemory(secret_key) => SharedSecret::new(&their_pub, secret_key),
 249                         NoiseSecretKey::NodeSigner(node_signer) => node_signer
 250                                 .ecdh(Recipient::Node, &their_pub, None)
 251                                 .map_err(|_| LightningError {
 252                                         err: "Failed to derive shared secret".to_owned(),
 253                                         action: msgs::ErrorAction::DisconnectPeer { msg: None }
 254                                 })?,
 255                 };
 256                 let temp_k = PeerChannelEncryptor::hkdf(state, ss);
 257
 258                 let mut dec = [0; 0];
 259                 PeerChannelEncryptor::decrypt_with_ad(&mut dec, 0, &temp_k, &state.h, &act[34..])?;
 260
 261                 let mut sha = Sha256::engine();
 262                 sha.input(&state.h);
 263                 sha.input(&act[34..]);
 264                 state.h = Sha256::from_engine(sha).into_inner();
 265
 266                 Ok((their_pub, temp_k))
 267         }
 268
 269         pub fn get_act_one<C: secp256k1::Signing>(&mut self, secp_ctx: &Secp256k1<C>) -> [u8; 50] {
 270                 match self.noise_state {
 271                         NoiseState::InProgress { ref mut state, ref directional_state, ref mut bidirectional_state } =>
 272                                 match directional_state {
 273                                         &DirectionalNoiseState::Outbound { ref ie } => {
 274                                                 if *state != NoiseStep::PreActOne {
 275                                                         panic!("Requested act at wrong step");
 276                                                 }
 277
 278                                                 let (res, _) = PeerChannelEncryptor::outbound_noise_act(secp_ctx, bidirectional_state, &ie, &self.their_node_id.unwrap());
 279                                                 *state = NoiseStep::PostActOne;
 280                                                 res
 281                                         },
 282                                         _ => panic!("Wrong direction for act"),
 283                                 },
 284                         _ => panic!("Cannot get act one after noise handshake completes"),
 285                 }
 286         }
 287
 288         pub fn process_act_one_with_keys<C: secp256k1::Signing, NS: Deref>(
 289                 &mut self, act_one: &[u8], node_signer: &NS, our_ephemeral: SecretKey, secp_ctx: &Secp256k1<C>)
 290         -> Result<[u8; 50], LightningError> where NS::Target: NodeSigner {
 291                 assert_eq!(act_one.len(), 50);
 292
 293                 match self.noise_state {
 294                         NoiseState::InProgress { ref mut state, ref mut directional_state, ref mut bidirectional_state } =>
 295                                 match directional_state {
 296                                         &mut DirectionalNoiseState::Inbound { ref mut ie, ref mut re, ref mut temp_k2 } => {
 297                                                 if *state != NoiseStep::PreActOne {
 298                                                         panic!("Requested act at wrong step");
 299                                                 }
 300
 301                                                 let (their_pub, _) = PeerChannelEncryptor::inbound_noise_act(bidirectional_state, act_one, NoiseSecretKey::NodeSigner(node_signer))?;
 302                                                 ie.get_or_insert(their_pub);
 303
 304                                                 re.get_or_insert(our_ephemeral);
 305
 306                                                 let (res, temp_k) =
 307                                                         PeerChannelEncryptor::outbound_noise_act(secp_ctx, bidirectional_state, &re.unwrap(), &ie.unwrap());
 308                                                 *temp_k2 = Some(temp_k);
 309                                                 *state = NoiseStep::PostActTwo;
 310                                                 Ok(res)
 311                                         },
 312                                         _ => panic!("Wrong direction for act"),
 313                                 },
 314                         _ => panic!("Cannot get act one after noise handshake completes"),
 315                 }
 316         }
 317
 318         pub fn process_act_two<NS: Deref>(
 319                 &mut self, act_two: &[u8], node_signer: &NS)
 320         -> Result<([u8; 66], PublicKey), LightningError> where NS::Target: NodeSigner {
 321                 assert_eq!(act_two.len(), 50);
 322
 323                 let final_hkdf;
 324                 let ck;
 325                 let res: [u8; 66] = match self.noise_state {
 326                         NoiseState::InProgress { ref state, ref directional_state, ref mut bidirectional_state } =>
 327                                 match directional_state {
 328                                         &DirectionalNoiseState::Outbound { ref ie } => {
 329                                                 if *state != NoiseStep::PostActOne {
 330                                                         panic!("Requested act at wrong step");
 331                                                 }
 332
 333                                                 let (re, temp_k2) = PeerChannelEncryptor::inbound_noise_act(bidirectional_state, act_two, NoiseSecretKey::<NS>::InMemory(&ie))?;
 334
 335                                                 let mut res = [0; 66];
 336                                                 let our_node_id = node_signer.get_node_id(Recipient::Node).map_err(|_| LightningError {
 337                                                         err: "Failed to encrypt message".to_owned(),
 338                                                         action: msgs::ErrorAction::DisconnectPeer { msg: None }
 339                                                 })?;
 340
 341                                                 PeerChannelEncryptor::encrypt_with_ad(&mut res[1..50], 1, &temp_k2, &bidirectional_state.h, &our_node_id.serialize()[..]);
 342
 343                                                 let mut sha = Sha256::engine();
 344                                                 sha.input(&bidirectional_state.h);
 345                                                 sha.input(&res[1..50]);
 346                                                 bidirectional_state.h = Sha256::from_engine(sha).into_inner();
 347
 348                                                 let ss = node_signer.ecdh(Recipient::Node, &re, None).map_err(|_| LightningError {
 349                                                         err: "Failed to derive shared secret".to_owned(),
 350                                                         action: msgs::ErrorAction::DisconnectPeer { msg: None }
 351                                                 })?;
 352                                                 let temp_k = PeerChannelEncryptor::hkdf(bidirectional_state, ss);
 353
 354                                                 PeerChannelEncryptor::encrypt_with_ad(&mut res[50..], 0, &temp_k, &bidirectional_state.h, &[0; 0]);
 355                                                 final_hkdf = hkdf_extract_expand_twice(&bidirectional_state.ck, &[0; 0]);
 356                                                 ck = bidirectional_state.ck.clone();
 357                                                 res
 358                                         },
 359                                         _ => panic!("Wrong direction for act"),
 360                                 },
 361                         _ => panic!("Cannot get act one after noise handshake completes"),
 362                 };
 363
 364                 let (sk, rk) = final_hkdf;
 365                 self.noise_state = NoiseState::Finished {
 366                         sk,
 367                         sn: 0,
 368                         sck: ck.clone(),
 369                         rk,
 370                         rn: 0,
 371                         rck: ck,
 372                 };
 373
 374                 Ok((res, self.their_node_id.unwrap().clone()))
 375         }
 376
 377         pub fn process_act_three(&mut self, act_three: &[u8]) -> Result<PublicKey, LightningError> {
 378                 assert_eq!(act_three.len(), 66);
 379
 380                 let final_hkdf;
 381                 let ck;
 382                 match self.noise_state {
 383                         NoiseState::InProgress { ref state, ref directional_state, ref mut bidirectional_state } =>
 384                                 match directional_state {
 385                                         &DirectionalNoiseState::Inbound { ie: _, ref re, ref temp_k2 } => {
 386                                                 if *state != NoiseStep::PostActTwo {
 387                                                         panic!("Requested act at wrong step");
 388                                                 }
 389                                                 if act_three[0] != 0 {
 390                                                         return Err(LightningError{err: format!("Unknown handshake version number {}", act_three[0]), action: msgs::ErrorAction::DisconnectPeer{ msg: None }});
 391                                                 }
 392
 393                                                 let mut their_node_id = [0; 33];
 394                                                 PeerChannelEncryptor::decrypt_with_ad(&mut their_node_id, 1, &temp_k2.unwrap(), &bidirectional_state.h, &act_three[1..50])?;
 395                                                 self.their_node_id = Some(match PublicKey::from_slice(&their_node_id) {
 396                                                         Ok(key) => key,
 397                                                         Err(_) => return Err(LightningError{err: format!("Bad node_id from peer, {}", &their_node_id.to_hex()), action: msgs::ErrorAction::DisconnectPeer{ msg: None }}),
 398                                                 });
 399
 400                                                 let mut sha = Sha256::engine();
 401                                                 sha.input(&bidirectional_state.h);
 402                                                 sha.input(&act_three[1..50]);
 403                                                 bidirectional_state.h = Sha256::from_engine(sha).into_inner();
 404
 405                                                 let ss = SharedSecret::new(&self.their_node_id.unwrap(), &re.unwrap());
 406                                                 let temp_k = PeerChannelEncryptor::hkdf(bidirectional_state, ss);
 407
 408                                                 PeerChannelEncryptor::decrypt_with_ad(&mut [0; 0], 0, &temp_k, &bidirectional_state.h, &act_three[50..])?;
 409                                                 final_hkdf = hkdf_extract_expand_twice(&bidirectional_state.ck, &[0; 0]);
 410                                                 ck = bidirectional_state.ck.clone();
 411                                         },
 412                                         _ => panic!("Wrong direction for act"),
 413                                 },
 414                         _ => panic!("Cannot get act one after noise handshake completes"),
 415                 }
 416
 417                 let (rk, sk) = final_hkdf;
 418                 self.noise_state = NoiseState::Finished {
 419                         sk,
 420                         sn: 0,
 421                         sck: ck.clone(),
 422                         rk,
 423                         rn: 0,
 424                         rck: ck,
 425                 };
 426
 427                 Ok(self.their_node_id.unwrap().clone())
 428         }
 429
 430         /// Builds sendable bytes for a message.
 431         ///
 432         /// `msgbuf` must begin with 16 + 2 dummy/0 bytes, which will be filled with the encrypted
 433         /// message length and its MAC. It should then be followed by the message bytes themselves
 434         /// (including the two byte message type).
 435         ///
 436         /// For effeciency, the [`Vec::capacity`] should be at least 16 bytes larger than the
 437         /// [`Vec::len`], to avoid reallocating for the message MAC, which will be appended to the vec.
 438         fn encrypt_message_with_header_0s(&mut self, msgbuf: &mut Vec<u8>) {
 439                 let msg_len = msgbuf.len() - 16 - 2;
 440                 if msg_len > LN_MAX_MSG_LEN {
 441                         panic!("Attempted to encrypt message longer than 65535 bytes!");
 442                 }
 443
 444                 match self.noise_state {
 445                         NoiseState::Finished { ref mut sk, ref mut sn, ref mut sck, rk: _, rn: _, rck: _ } => {
 446                                 if *sn >= 1000 {
 447                                         let (new_sck, new_sk) = hkdf_extract_expand_twice(sck, sk);
 448                                         *sck = new_sck;
 449                                         *sk = new_sk;
 450                                         *sn = 0;
 451                                 }
 452
 453                                 Self::encrypt_with_ad(&mut msgbuf[0..16+2], *sn, sk, &[0; 0], &(msg_len as u16).to_be_bytes());
 454                                 *sn += 1;
 455
 456                                 Self::encrypt_in_place_with_ad(msgbuf, 16+2, *sn, sk, &[0; 0]);
 457                                 *sn += 1;
 458                         },
 459                         _ => panic!("Tried to encrypt a message prior to noise handshake completion"),
 460                 }
 461         }
 462
 463         /// Encrypts the given pre-serialized message, returning the encrypted version.
 464         /// panics if msg.len() > 65535 or Noise handshake has not finished.
 465         pub fn encrypt_buffer(&mut self, mut msg: MessageBuf) -> Vec<u8> {
 466                 self.encrypt_message_with_header_0s(&mut msg.0);
 467                 msg.0
 468         }
 469
 470         /// Encrypts the given message, returning the encrypted version.
 471         /// panics if the length of `message`, once encoded, is greater than 65535 or if the Noise
 472         /// handshake has not finished.
 473         pub fn encrypt_message<M: wire::Type>(&mut self, message: &M) -> Vec<u8> {
 474                 // Allocate a buffer with 2KB, fitting most common messages. Reserve the first 16+2 bytes
 475                 // for the 2-byte message type prefix and its MAC.
 476                 let mut res = VecWriter(Vec::with_capacity(MSG_BUF_ALLOC_SIZE));
 477                 res.0.resize(16 + 2, 0);
 478                 wire::write(message, &mut res).expect("In-memory messages must never fail to serialize");
 479
 480                 self.encrypt_message_with_header_0s(&mut res.0);
 481                 res.0
 482         }
 483
 484         /// Decrypts a message length header from the remote peer.
 485         /// panics if noise handshake has not yet finished or msg.len() != 18
 486         pub fn decrypt_length_header(&mut self, msg: &[u8]) -> Result<u16, LightningError> {
 487                 assert_eq!(msg.len(), 16+2);
 488
 489                 match self.noise_state {
 490                         NoiseState::Finished { sk: _, sn: _, sck: _, ref mut rk, ref mut rn, ref mut rck } => {
 491                                 if *rn >= 1000 {
 492                                         let (new_rck, new_rk) = hkdf_extract_expand_twice(rck, rk);
 493                                         *rck = new_rck;
 494                                         *rk = new_rk;
 495                                         *rn = 0;
 496                                 }
 497
 498                                 let mut res = [0; 2];
 499                                 Self::decrypt_with_ad(&mut res, *rn, rk, &[0; 0], msg)?;
 500                                 *rn += 1;
 501                                 Ok(u16::from_be_bytes(res))
 502                         },
 503                         _ => panic!("Tried to decrypt a message prior to noise handshake completion"),
 504                 }
 505         }
 506
 507         /// Decrypts the given message up to msg.len() - 16. Bytes after msg.len() - 16 will be left
 508         /// undefined (as they contain the Poly1305 tag bytes).
 509         ///
 510         /// panics if msg.len() > 65535 + 16
 511         pub fn decrypt_message(&mut self, msg: &mut [u8]) -> Result<(), LightningError> {
 512                 if msg.len() > LN_MAX_MSG_LEN + 16 {
 513                         panic!("Attempted to decrypt message longer than 65535 + 16 bytes!");
 514                 }
 515
 516                 match self.noise_state {
 517                         NoiseState::Finished { sk: _, sn: _, sck: _, ref rk, ref mut rn, rck: _ } => {
 518                                 Self::decrypt_in_place_with_ad(&mut msg[..], *rn, rk, &[0; 0])?;
 519                                 *rn += 1;
 520                                 Ok(())
 521                         },
 522                         _ => panic!("Tried to decrypt a message prior to noise handshake completion"),
 523                 }
 524         }
 525
 526         pub fn get_noise_step(&self) -> NextNoiseStep {
 527                 match self.noise_state {
 528                         NoiseState::InProgress {ref state, ..} => {
 529                                 match state {
 530                                         &NoiseStep::PreActOne => NextNoiseStep::ActOne,
 531                                         &NoiseStep::PostActOne => NextNoiseStep::ActTwo,
 532                                         &NoiseStep::PostActTwo => NextNoiseStep::ActThree,
 533                                 }
 534                         },
 535                         NoiseState::Finished {..} => NextNoiseStep::NoiseComplete,
 536                 }
 537         }
 538
 539         pub fn is_ready_for_encryption(&self) -> bool {
 540                 match self.noise_state {
 541                         NoiseState::InProgress {..} => { false },
 542                         NoiseState::Finished {..} => { true }
 543                 }
 544         }
 545 }
 546
 547 /// A buffer which stores an encoded message (including the two message-type bytes) with some
 548 /// padding to allow for future encryption/MACing.
 549 pub struct MessageBuf(Vec<u8>);
 550 impl MessageBuf {
 551         /// Creates a new buffer from an encoded message (i.e. the two message-type bytes followed by
 552         /// the message contents).
 553         ///
 554         /// Panics if the message is longer than 2^16.
 555         pub fn from_encoded(encoded_msg: &[u8]) -> Self {
 556                 if encoded_msg.len() > LN_MAX_MSG_LEN {
 557                         panic!("Attempted to encrypt message longer than 65535 bytes!");
 558                 }
 559                 // In addition to the message (continaing the two message type bytes), we also have to add
 560                 // the message length header (and its MAC) and the message MAC.
 561                 let mut res = Vec::with_capacity(encoded_msg.len() + 16*2 + 2);
 562                 res.resize(encoded_msg.len() + 16 + 2, 0);
 563                 res[16 + 2..].copy_from_slice(&encoded_msg);
 564                 Self(res)
 565         }
 566 }
 567
 568 #[cfg(test)]
 569 mod tests {
 570         use super::{MessageBuf, LN_MAX_MSG_LEN};
 571
 572         use bitcoin::secp256k1::{PublicKey, SecretKey};
 573         use bitcoin::secp256k1::Secp256k1;
 574
 575         use hex;
 576
 577         use crate::ln::peer_channel_encryptor::{PeerChannelEncryptor,NoiseState};
 578         use crate::util::test_utils::TestNodeSigner;
 579
 580         fn get_outbound_peer_for_initiator_test_vectors() -> PeerChannelEncryptor {
 581                 let their_node_id = PublicKey::from_slice(&hex::decode("028d7500dd4c12685d1f568b4c2b5048e8534b873319f3a8daa612b469132ec7f7").unwrap()[..]).unwrap();
 582                 let secp_ctx = Secp256k1::signing_only();
 583
 584                 let mut outbound_peer = PeerChannelEncryptor::new_outbound(their_node_id, SecretKey::from_slice(&hex::decode("1212121212121212121212121212121212121212121212121212121212121212").unwrap()[..]).unwrap());
 585                 assert_eq!(outbound_peer.get_act_one(&secp_ctx)[..], hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap()[..]);
 586                 outbound_peer
 587         }
 588
 589         fn get_inbound_peer_for_test_vectors() -> PeerChannelEncryptor {
 590                 // transport-responder successful handshake
 591                 let our_node_id = SecretKey::from_slice(&hex::decode("2121212121212121212121212121212121212121212121212121212121212121").unwrap()[..]).unwrap();
 592                 let our_ephemeral = SecretKey::from_slice(&hex::decode("2222222222222222222222222222222222222222222222222222222222222222").unwrap()[..]).unwrap();
 593                 let secp_ctx = Secp256k1::new();
 594                 let node_signer = TestNodeSigner::new(our_node_id);
 595
 596                 let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 597
 598                 let act_one = hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
 599                 assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
 600
 601                 let act_three = hex::decode("00b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap().to_vec();
 602                 // test vector doesn't specify the initiator static key, but it's the same as the one
 603                 // from transport-initiator successful handshake
 604                 assert_eq!(inbound_peer.process_act_three(&act_three[..]).unwrap().serialize()[..], hex::decode("034f355bdcb7cc0af728ef3cceb9615d90684bb5b2ca5f859ab0f0b704075871aa").unwrap()[..]);
 605
 606                 match inbound_peer.noise_state {
 607                         NoiseState::Finished { sk, sn, sck, rk, rn, rck } => {
 608                                 assert_eq!(sk, hex::decode("bb9020b8965f4df047e07f955f3c4b88418984aadc5cdb35096b9ea8fa5c3442").unwrap()[..]);
 609                                 assert_eq!(sn, 0);
 610                                 assert_eq!(sck, hex::decode("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
 611                                 assert_eq!(rk, hex::decode("969ab31b4d288cedf6218839b27a3e2140827047f2c0f01bf5c04435d43511a9").unwrap()[..]);
 612                                 assert_eq!(rn, 0);
 613                                 assert_eq!(rck, hex::decode("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
 614                         },
 615                         _ => panic!()
 616                 }
 617
 618                 inbound_peer
 619         }
 620
 621         #[test]
 622         fn noise_initiator_test_vectors() {
 623                 let our_node_id = SecretKey::from_slice(&hex::decode("1111111111111111111111111111111111111111111111111111111111111111").unwrap()[..]).unwrap();
 624                 let node_signer = TestNodeSigner::new(our_node_id);
 625
 626                 {
 627                         // transport-initiator successful handshake
 628                         let mut outbound_peer = get_outbound_peer_for_initiator_test_vectors();
 629
 630                         let act_two = hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap().to_vec();
 631                         assert_eq!(outbound_peer.process_act_two(&act_two[..], &&node_signer).unwrap().0[..], hex::decode("00b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap()[..]);
 632
 633                         match outbound_peer.noise_state {
 634                                 NoiseState::Finished { sk, sn, sck, rk, rn, rck } => {
 635                                         assert_eq!(sk, hex::decode("969ab31b4d288cedf6218839b27a3e2140827047f2c0f01bf5c04435d43511a9").unwrap()[..]);
 636                                         assert_eq!(sn, 0);
 637                                         assert_eq!(sck, hex::decode("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
 638                                         assert_eq!(rk, hex::decode("bb9020b8965f4df047e07f955f3c4b88418984aadc5cdb35096b9ea8fa5c3442").unwrap()[..]);
 639                                         assert_eq!(rn, 0);
 640                                         assert_eq!(rck, hex::decode("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
 641                                 },
 642                                 _ => panic!()
 643                         }
 644                 }
 645                 {
 646                         // transport-initiator act2 short read test
 647                         // Can't actually test this cause process_act_two requires you pass the right length!
 648                 }
 649                 {
 650                         // transport-initiator act2 bad version test
 651                         let mut outbound_peer = get_outbound_peer_for_initiator_test_vectors();
 652
 653                         let act_two = hex::decode("0102466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap().to_vec();
 654                         assert!(outbound_peer.process_act_two(&act_two[..], &&node_signer).is_err());
 655                 }
 656
 657                 {
 658                         // transport-initiator act2 bad key serialization test
 659                         let mut outbound_peer = get_outbound_peer_for_initiator_test_vectors();
 660
 661                         let act_two = hex::decode("0004466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap().to_vec();
 662                         assert!(outbound_peer.process_act_two(&act_two[..], &&node_signer).is_err());
 663                 }
 664
 665                 {
 666                         // transport-initiator act2 bad MAC test
 667                         let mut outbound_peer = get_outbound_peer_for_initiator_test_vectors();
 668
 669                         let act_two = hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730af").unwrap().to_vec();
 670                         assert!(outbound_peer.process_act_two(&act_two[..], &&node_signer).is_err());
 671                 }
 672         }
 673
 674         #[test]
 675         fn noise_responder_test_vectors() {
 676                 let our_node_id = SecretKey::from_slice(&hex::decode("2121212121212121212121212121212121212121212121212121212121212121").unwrap()[..]).unwrap();
 677                 let our_ephemeral = SecretKey::from_slice(&hex::decode("2222222222222222222222222222222222222222222222222222222222222222").unwrap()[..]).unwrap();
 678                 let secp_ctx = Secp256k1::new();
 679                 let node_signer = TestNodeSigner::new(our_node_id);
 680
 681                 {
 682                         let _ = get_inbound_peer_for_test_vectors();
 683                 }
 684                 {
 685                         // transport-responder act1 short read test
 686                         // Can't actually test this cause process_act_one requires you pass the right length!
 687                 }
 688                 {
 689                         // transport-responder act1 bad version test
 690                         let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 691
 692                         let act_one = hex::decode("01036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
 693                         assert!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).is_err());
 694                 }
 695                 {
 696                         // transport-responder act1 bad key serialization test
 697                         let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 698
 699                         let act_one =hex::decode("00046360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
 700                         assert!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).is_err());
 701                 }
 702                 {
 703                         // transport-responder act1 bad MAC test
 704                         let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 705
 706                         let act_one = hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6b").unwrap().to_vec();
 707                         assert!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).is_err());
 708                 }
 709                 {
 710                         // transport-responder act3 bad version test
 711                         let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 712
 713                         let act_one = hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
 714                         assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
 715
 716                         let act_three = hex::decode("01b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap().to_vec();
 717                         assert!(inbound_peer.process_act_three(&act_three[..]).is_err());
 718                 }
 719                 {
 720                         // transport-responder act3 short read test
 721                         // Can't actually test this cause process_act_three requires you pass the right length!
 722                 }
 723                 {
 724                         // transport-responder act3 bad MAC for ciphertext test
 725                         let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 726
 727                         let act_one = hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
 728                         assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
 729
 730                         let act_three = hex::decode("00c9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap().to_vec();
 731                         assert!(inbound_peer.process_act_three(&act_three[..]).is_err());
 732                 }
 733                 {
 734                         // transport-responder act3 bad rs test
 735                         let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 736
 737                         let act_one = hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
 738                         assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
 739
 740                         let act_three = hex::decode("00bfe3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa2235536ad09a8ee351870c2bb7f78b754a26c6cef79a98d25139c856d7efd252c2ae73c").unwrap().to_vec();
 741                         assert!(inbound_peer.process_act_three(&act_three[..]).is_err());
 742                 }
 743                 {
 744                         // transport-responder act3 bad MAC test
 745                         let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 746
 747                         let act_one = hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
 748                         assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
 749
 750                         let act_three = hex::decode("00b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139bb").unwrap().to_vec();
 751                         assert!(inbound_peer.process_act_three(&act_three[..]).is_err());
 752                 }
 753         }
 754
 755
 756         #[test]
 757         fn message_encryption_decryption_test_vectors() {
 758                 // We use the same keys as the initiator and responder test vectors, so we copy those tests
 759                 // here and use them to encrypt.
 760                 let mut outbound_peer = get_outbound_peer_for_initiator_test_vectors();
 761
 762                 {
 763                         let our_node_id = SecretKey::from_slice(&hex::decode("1111111111111111111111111111111111111111111111111111111111111111").unwrap()[..]).unwrap();
 764                         let node_signer = TestNodeSigner::new(our_node_id);
 765
 766                         let act_two = hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap().to_vec();
 767                         assert_eq!(outbound_peer.process_act_two(&act_two[..], &&node_signer).unwrap().0[..], hex::decode("00b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap()[..]);
 768
 769                         match outbound_peer.noise_state {
 770                                 NoiseState::Finished { sk, sn, sck, rk, rn, rck } => {
 771                                         assert_eq!(sk, hex::decode("969ab31b4d288cedf6218839b27a3e2140827047f2c0f01bf5c04435d43511a9").unwrap()[..]);
 772                                         assert_eq!(sn, 0);
 773                                         assert_eq!(sck, hex::decode("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
 774                                         assert_eq!(rk, hex::decode("bb9020b8965f4df047e07f955f3c4b88418984aadc5cdb35096b9ea8fa5c3442").unwrap()[..]);
 775                                         assert_eq!(rn, 0);
 776                                         assert_eq!(rck, hex::decode("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
 777                                 },
 778                                 _ => panic!()
 779                         }
 780                 }
 781
 782                 let mut inbound_peer = get_inbound_peer_for_test_vectors();
 783
 784                 for i in 0..1005 {
 785                         let msg = [0x68, 0x65, 0x6c, 0x6c, 0x6f];
 786                         let mut res = outbound_peer.encrypt_buffer(MessageBuf::from_encoded(&msg));
 787                         assert_eq!(res.len(), 5 + 2*16 + 2);
 788
 789                         let len_header = res[0..2+16].to_vec();
 790                         assert_eq!(inbound_peer.decrypt_length_header(&len_header[..]).unwrap() as usize, msg.len());
 791
 792                         if i == 0 {
 793                                 assert_eq!(res, hex::decode("cf2b30ddf0cf3f80e7c35a6e6730b59fe802473180f396d88a8fb0db8cbcf25d2f214cf9ea1d95").unwrap());
 794                         } else if i == 1 {
 795                                 assert_eq!(res, hex::decode("72887022101f0b6753e0c7de21657d35a4cb2a1f5cde2650528bbc8f837d0f0d7ad833b1a256a1").unwrap());
 796                         } else if i == 500 {
 797                                 assert_eq!(res, hex::decode("178cb9d7387190fa34db9c2d50027d21793c9bc2d40b1e14dcf30ebeeeb220f48364f7a4c68bf8").unwrap());
 798                         } else if i == 501 {
 799                                 assert_eq!(res, hex::decode("1b186c57d44eb6de4c057c49940d79bb838a145cb528d6e8fd26dbe50a60ca2c104b56b60e45bd").unwrap());
 800                         } else if i == 1000 {
 801                                 assert_eq!(res, hex::decode("4a2f3cc3b5e78ddb83dcb426d9863d9d9a723b0337c89dd0b005d89f8d3c05c52b76b29b740f09").unwrap());
 802                         } else if i == 1001 {
 803                                 assert_eq!(res, hex::decode("2ecd8c8a5629d0d02ab457a0fdd0f7b90a192cd46be5ecb6ca570bfc5e268338b1a16cf4ef2d36").unwrap());
 804                         }
 805
 806                         inbound_peer.decrypt_message(&mut res[2+16..]).unwrap();
 807                         assert_eq!(res[2 + 16..res.len() - 16], msg[..]);
 808                 }
 809         }
 810
 811         #[test]
 812         fn max_msg_len_limit_value() {
 813                 assert_eq!(LN_MAX_MSG_LEN, 65535);
 814                 assert_eq!(LN_MAX_MSG_LEN, ::core::u16::MAX as usize);
 815         }
 816
 817         #[test]
 818         #[should_panic(expected = "Attempted to encrypt message longer than 65535 bytes!")]
 819         fn max_message_len_encryption() {
 820                 let mut outbound_peer = get_outbound_peer_for_initiator_test_vectors();
 821                 let msg = [4u8; LN_MAX_MSG_LEN + 1];
 822                 outbound_peer.encrypt_buffer(MessageBuf::from_encoded(&msg));
 823         }
 824
 825         #[test]
 826         #[should_panic(expected = "Attempted to decrypt message longer than 65535 + 16 bytes!")]
 827         fn max_message_len_decryption() {
 828                 let mut inbound_peer = get_inbound_peer_for_test_vectors();
 829
 830                 // MSG should not exceed LN_MAX_MSG_LEN + 16
 831                 let mut msg = [4u8; LN_MAX_MSG_LEN + 17];
 832                 inbound_peer.decrypt_message(&mut msg).unwrap();
 833         }
 834 }