Bump rust-bitcoin to v0.30.2
[rust-lightning] / 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 hex::DisplayHex;
26
27 use crate::util::chacha20poly1305rfc::ChaCha20Poly1305RFC;
28 use crate::util::crypto::hkdf_extract_expand_twice;
29 use crate::util::ser::VecWriter;
30
31 use core::ops::Deref;
32
33 /// Maximum Lightning message data length according to
34 /// [BOLT-8](https://github.com/lightning/bolts/blob/v1.0/08-transport.md#lightning-message-specification)
35 /// and [BOLT-1](https://github.com/lightning/bolts/blob/master/01-messaging.md#lightning-message-format):
36 pub const LN_MAX_MSG_LEN: usize = ::core::u16::MAX as usize; // Must be equal to 65535
37
38 /// The (rough) size buffer to pre-allocate when encoding a message. Messages should reliably be
39 /// smaller than this size by at least 32 bytes or so.
40 pub const MSG_BUF_ALLOC_SIZE: usize = 2048;
41
42 // Sha256("Noise_XK_secp256k1_ChaChaPoly_SHA256")
43 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];
44 // Sha256(NOISE_CK || "lightning")
45 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];
46
47 enum NoiseSecretKey<'a, 'b, NS: Deref> where NS::Target: NodeSigner {
48         InMemory(&'a SecretKey),
49         NodeSigner(&'b NS)
50 }
51
52 pub enum NextNoiseStep {
53         ActOne,
54         ActTwo,
55         ActThree,
56         NoiseComplete,
57 }
58
59 #[derive(PartialEq)]
60 enum NoiseStep {
61         PreActOne,
62         PostActOne,
63         PostActTwo,
64         // When done swap noise_state for NoiseState::Finished
65 }
66
67 struct BidirectionalNoiseState {
68         h: [u8; 32],
69         ck: [u8; 32],
70 }
71 enum DirectionalNoiseState {
72         Outbound {
73                 ie: SecretKey,
74         },
75         Inbound {
76                 ie: Option<PublicKey>, // filled in if state >= PostActOne
77                 re: Option<SecretKey>, // filled in if state >= PostActTwo
78                 temp_k2: Option<[u8; 32]>, // filled in if state >= PostActTwo
79         }
80 }
81 enum NoiseState {
82         InProgress {
83                 state: NoiseStep,
84                 directional_state: DirectionalNoiseState,
85                 bidirectional_state: BidirectionalNoiseState,
86         },
87         Finished {
88                 sk: [u8; 32],
89                 sn: u64,
90                 sck: [u8; 32],
91                 rk: [u8; 32],
92                 rn: u64,
93                 rck: [u8; 32],
94         }
95 }
96
97 pub struct PeerChannelEncryptor {
98         their_node_id: Option<PublicKey>, // filled in for outbound, or inbound after noise_state is Finished
99
100         noise_state: NoiseState,
101 }
102
103 impl PeerChannelEncryptor {
104         pub fn new_outbound(their_node_id: PublicKey, ephemeral_key: SecretKey) -> PeerChannelEncryptor {
105                 let mut sha = Sha256::engine();
106                 sha.input(&NOISE_H);
107                 sha.input(&their_node_id.serialize()[..]);
108                 let h = Sha256::from_engine(sha).to_byte_array();
109
110                 PeerChannelEncryptor {
111                         their_node_id: Some(their_node_id),
112                         noise_state: NoiseState::InProgress {
113                                 state: NoiseStep::PreActOne,
114                                 directional_state: DirectionalNoiseState::Outbound {
115                                         ie: ephemeral_key,
116                                 },
117                                 bidirectional_state: BidirectionalNoiseState {
118                                         h,
119                                         ck: NOISE_CK,
120                                 },
121                         }
122                 }
123         }
124
125         pub fn new_inbound<NS: Deref>(node_signer: &NS) -> PeerChannelEncryptor where NS::Target: NodeSigner {
126                 let mut sha = Sha256::engine();
127                 sha.input(&NOISE_H);
128                 let our_node_id = node_signer.get_node_id(Recipient::Node).unwrap();
129                 sha.input(&our_node_id.serialize()[..]);
130                 let h = Sha256::from_engine(sha).to_byte_array();
131
132                 PeerChannelEncryptor {
133                         their_node_id: None,
134                         noise_state: NoiseState::InProgress {
135                                 state: NoiseStep::PreActOne,
136                                 directional_state: DirectionalNoiseState::Inbound {
137                                         ie: None,
138                                         re: None,
139                                         temp_k2: None,
140                                 },
141                                 bidirectional_state: BidirectionalNoiseState {
142                                         h,
143                                         ck: NOISE_CK,
144                                 },
145                         }
146                 }
147         }
148
149         #[inline]
150         fn encrypt_with_ad(res: &mut[u8], n: u64, key: &[u8; 32], h: &[u8], plaintext: &[u8]) {
151                 let mut nonce = [0; 12];
152                 nonce[4..].copy_from_slice(&n.to_le_bytes()[..]);
153
154                 let mut chacha = ChaCha20Poly1305RFC::new(key, &nonce, h);
155                 let mut tag = [0; 16];
156                 chacha.encrypt(plaintext, &mut res[0..plaintext.len()], &mut tag);
157                 res[plaintext.len()..].copy_from_slice(&tag);
158         }
159
160         #[inline]
161         /// Encrypts the message in res[offset..] in-place and pushes a 16-byte tag onto the end of
162         /// res.
163         fn encrypt_in_place_with_ad(res: &mut Vec<u8>, offset: usize, n: u64, key: &[u8; 32], h: &[u8]) {
164                 let mut nonce = [0; 12];
165                 nonce[4..].copy_from_slice(&n.to_le_bytes()[..]);
166
167                 let mut chacha = ChaCha20Poly1305RFC::new(key, &nonce, h);
168                 let mut tag = [0; 16];
169                 chacha.encrypt_full_message_in_place(&mut res[offset..], &mut tag);
170                 res.extend_from_slice(&tag);
171         }
172
173         fn decrypt_in_place_with_ad(inout: &mut [u8], n: u64, key: &[u8; 32], h: &[u8]) -> Result<(), LightningError> {
174                 let mut nonce = [0; 12];
175                 nonce[4..].copy_from_slice(&n.to_le_bytes()[..]);
176
177                 let mut chacha = ChaCha20Poly1305RFC::new(key, &nonce, h);
178                 let (inout, tag) = inout.split_at_mut(inout.len() - 16);
179                 if chacha.check_decrypt_in_place(inout, tag).is_err() {
180                         return Err(LightningError{err: "Bad MAC".to_owned(), action: msgs::ErrorAction::DisconnectPeer{ msg: None }});
181                 }
182                 Ok(())
183         }
184
185         #[inline]
186         fn decrypt_with_ad(res: &mut[u8], n: u64, key: &[u8; 32], h: &[u8], cyphertext: &[u8]) -> Result<(), LightningError> {
187                 let mut nonce = [0; 12];
188                 nonce[4..].copy_from_slice(&n.to_le_bytes()[..]);
189
190                 let mut chacha = ChaCha20Poly1305RFC::new(key, &nonce, h);
191                 if !chacha.decrypt(&cyphertext[0..cyphertext.len() - 16], res, &cyphertext[cyphertext.len() - 16..]) {
192                         return Err(LightningError{err: "Bad MAC".to_owned(), action: msgs::ErrorAction::DisconnectPeer{ msg: None }});
193                 }
194                 Ok(())
195         }
196
197         #[inline]
198         fn hkdf(state: &mut BidirectionalNoiseState, ss: SharedSecret) -> [u8; 32] {
199                 let (t1, t2) = hkdf_extract_expand_twice(&state.ck, ss.as_ref());
200                 state.ck = t1;
201                 t2
202         }
203
204         #[inline]
205         fn outbound_noise_act<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, state: &mut BidirectionalNoiseState, our_key: &SecretKey, their_key: &PublicKey) -> ([u8; 50], [u8; 32]) {
206                 let our_pub = PublicKey::from_secret_key(secp_ctx, &our_key);
207
208                 let mut sha = Sha256::engine();
209                 sha.input(&state.h);
210                 sha.input(&our_pub.serialize()[..]);
211                 state.h = Sha256::from_engine(sha).to_byte_array();
212
213                 let ss = SharedSecret::new(&their_key, &our_key);
214                 let temp_k = PeerChannelEncryptor::hkdf(state, ss);
215
216                 let mut res = [0; 50];
217                 res[1..34].copy_from_slice(&our_pub.serialize()[..]);
218                 PeerChannelEncryptor::encrypt_with_ad(&mut res[34..], 0, &temp_k, &state.h, &[0; 0]);
219
220                 let mut sha = Sha256::engine();
221                 sha.input(&state.h);
222                 sha.input(&res[34..]);
223                 state.h = Sha256::from_engine(sha).to_byte_array();
224
225                 (res, temp_k)
226         }
227
228         #[inline]
229         fn inbound_noise_act<'a, 'b, NS: Deref>(
230                 state: &mut BidirectionalNoiseState, act: &[u8], secret_key: NoiseSecretKey<'a, 'b, NS>
231         ) -> Result<(PublicKey, [u8; 32]), LightningError> where NS::Target: NodeSigner {
232                 assert_eq!(act.len(), 50);
233
234                 if act[0] != 0 {
235                         return Err(LightningError{err: format!("Unknown handshake version number {}", act[0]), action: msgs::ErrorAction::DisconnectPeer{ msg: None }});
236                 }
237
238                 let their_pub = match PublicKey::from_slice(&act[1..34]) {
239                         Err(_) => return Err(LightningError{err: format!("Invalid public key {}", &act[1..34].as_hex()), action: msgs::ErrorAction::DisconnectPeer{ msg: None }}),
240                         Ok(key) => key,
241                 };
242
243                 let mut sha = Sha256::engine();
244                 sha.input(&state.h);
245                 sha.input(&their_pub.serialize()[..]);
246                 state.h = Sha256::from_engine(sha).to_byte_array();
247
248                 let ss = match secret_key {
249                         NoiseSecretKey::InMemory(secret_key) => SharedSecret::new(&their_pub, secret_key),
250                         NoiseSecretKey::NodeSigner(node_signer) => node_signer
251                                 .ecdh(Recipient::Node, &their_pub, None)
252                                 .map_err(|_| LightningError {
253                                         err: "Failed to derive shared secret".to_owned(),
254                                         action: msgs::ErrorAction::DisconnectPeer { msg: None }
255                                 })?,
256                 };
257                 let temp_k = PeerChannelEncryptor::hkdf(state, ss);
258
259                 let mut dec = [0; 0];
260                 PeerChannelEncryptor::decrypt_with_ad(&mut dec, 0, &temp_k, &state.h, &act[34..])?;
261
262                 let mut sha = Sha256::engine();
263                 sha.input(&state.h);
264                 sha.input(&act[34..]);
265                 state.h = Sha256::from_engine(sha).to_byte_array();
266
267                 Ok((their_pub, temp_k))
268         }
269
270         pub fn get_act_one<C: secp256k1::Signing>(&mut self, secp_ctx: &Secp256k1<C>) -> [u8; 50] {
271                 match self.noise_state {
272                         NoiseState::InProgress { ref mut state, ref directional_state, ref mut bidirectional_state } =>
273                                 match directional_state {
274                                         &DirectionalNoiseState::Outbound { ref ie } => {
275                                                 if *state != NoiseStep::PreActOne {
276                                                         panic!("Requested act at wrong step");
277                                                 }
278
279                                                 let (res, _) = PeerChannelEncryptor::outbound_noise_act(secp_ctx, bidirectional_state, &ie, &self.their_node_id.unwrap());
280                                                 *state = NoiseStep::PostActOne;
281                                                 res
282                                         },
283                                         _ => panic!("Wrong direction for act"),
284                                 },
285                         _ => panic!("Cannot get act one after noise handshake completes"),
286                 }
287         }
288
289         pub fn process_act_one_with_keys<C: secp256k1::Signing, NS: Deref>(
290                 &mut self, act_one: &[u8], node_signer: &NS, our_ephemeral: SecretKey, secp_ctx: &Secp256k1<C>)
291         -> Result<[u8; 50], LightningError> where NS::Target: NodeSigner {
292                 assert_eq!(act_one.len(), 50);
293
294                 match self.noise_state {
295                         NoiseState::InProgress { ref mut state, ref mut directional_state, ref mut bidirectional_state } =>
296                                 match directional_state {
297                                         &mut DirectionalNoiseState::Inbound { ref mut ie, ref mut re, ref mut temp_k2 } => {
298                                                 if *state != NoiseStep::PreActOne {
299                                                         panic!("Requested act at wrong step");
300                                                 }
301
302                                                 let (their_pub, _) = PeerChannelEncryptor::inbound_noise_act(bidirectional_state, act_one, NoiseSecretKey::NodeSigner(node_signer))?;
303                                                 ie.get_or_insert(their_pub);
304
305                                                 re.get_or_insert(our_ephemeral);
306
307                                                 let (res, temp_k) =
308                                                         PeerChannelEncryptor::outbound_noise_act(secp_ctx, bidirectional_state, &re.unwrap(), &ie.unwrap());
309                                                 *temp_k2 = Some(temp_k);
310                                                 *state = NoiseStep::PostActTwo;
311                                                 Ok(res)
312                                         },
313                                         _ => panic!("Wrong direction for act"),
314                                 },
315                         _ => panic!("Cannot get act one after noise handshake completes"),
316                 }
317         }
318
319         pub fn process_act_two<NS: Deref>(
320                 &mut self, act_two: &[u8], node_signer: &NS)
321         -> Result<([u8; 66], PublicKey), LightningError> where NS::Target: NodeSigner {
322                 assert_eq!(act_two.len(), 50);
323
324                 let final_hkdf;
325                 let ck;
326                 let res: [u8; 66] = match self.noise_state {
327                         NoiseState::InProgress { ref state, ref directional_state, ref mut bidirectional_state } =>
328                                 match directional_state {
329                                         &DirectionalNoiseState::Outbound { ref ie } => {
330                                                 if *state != NoiseStep::PostActOne {
331                                                         panic!("Requested act at wrong step");
332                                                 }
333
334                                                 let (re, temp_k2) = PeerChannelEncryptor::inbound_noise_act(bidirectional_state, act_two, NoiseSecretKey::<NS>::InMemory(&ie))?;
335
336                                                 let mut res = [0; 66];
337                                                 let our_node_id = node_signer.get_node_id(Recipient::Node).map_err(|_| LightningError {
338                                                         err: "Failed to encrypt message".to_owned(),
339                                                         action: msgs::ErrorAction::DisconnectPeer { msg: None }
340                                                 })?;
341
342                                                 PeerChannelEncryptor::encrypt_with_ad(&mut res[1..50], 1, &temp_k2, &bidirectional_state.h, &our_node_id.serialize()[..]);
343
344                                                 let mut sha = Sha256::engine();
345                                                 sha.input(&bidirectional_state.h);
346                                                 sha.input(&res[1..50]);
347                                                 bidirectional_state.h = Sha256::from_engine(sha).to_byte_array();
348
349                                                 let ss = node_signer.ecdh(Recipient::Node, &re, None).map_err(|_| LightningError {
350                                                         err: "Failed to derive shared secret".to_owned(),
351                                                         action: msgs::ErrorAction::DisconnectPeer { msg: None }
352                                                 })?;
353                                                 let temp_k = PeerChannelEncryptor::hkdf(bidirectional_state, ss);
354
355                                                 PeerChannelEncryptor::encrypt_with_ad(&mut res[50..], 0, &temp_k, &bidirectional_state.h, &[0; 0]);
356                                                 final_hkdf = hkdf_extract_expand_twice(&bidirectional_state.ck, &[0; 0]);
357                                                 ck = bidirectional_state.ck.clone();
358                                                 res
359                                         },
360                                         _ => panic!("Wrong direction for act"),
361                                 },
362                         _ => panic!("Cannot get act one after noise handshake completes"),
363                 };
364
365                 let (sk, rk) = final_hkdf;
366                 self.noise_state = NoiseState::Finished {
367                         sk,
368                         sn: 0,
369                         sck: ck.clone(),
370                         rk,
371                         rn: 0,
372                         rck: ck,
373                 };
374
375                 Ok((res, self.their_node_id.unwrap().clone()))
376         }
377
378         pub fn process_act_three(&mut self, act_three: &[u8]) -> Result<PublicKey, LightningError> {
379                 assert_eq!(act_three.len(), 66);
380
381                 let final_hkdf;
382                 let ck;
383                 match self.noise_state {
384                         NoiseState::InProgress { ref state, ref directional_state, ref mut bidirectional_state } =>
385                                 match directional_state {
386                                         &DirectionalNoiseState::Inbound { ie: _, ref re, ref temp_k2 } => {
387                                                 if *state != NoiseStep::PostActTwo {
388                                                         panic!("Requested act at wrong step");
389                                                 }
390                                                 if act_three[0] != 0 {
391                                                         return Err(LightningError{err: format!("Unknown handshake version number {}", act_three[0]), action: msgs::ErrorAction::DisconnectPeer{ msg: None }});
392                                                 }
393
394                                                 let mut their_node_id = [0; 33];
395                                                 PeerChannelEncryptor::decrypt_with_ad(&mut their_node_id, 1, &temp_k2.unwrap(), &bidirectional_state.h, &act_three[1..50])?;
396                                                 self.their_node_id = Some(match PublicKey::from_slice(&their_node_id) {
397                                                         Ok(key) => key,
398                                                         Err(_) => return Err(LightningError{err: format!("Bad node_id from peer, {}", &their_node_id.as_hex()), action: msgs::ErrorAction::DisconnectPeer{ msg: None }}),
399                                                 });
400
401                                                 let mut sha = Sha256::engine();
402                                                 sha.input(&bidirectional_state.h);
403                                                 sha.input(&act_three[1..50]);
404                                                 bidirectional_state.h = Sha256::from_engine(sha).to_byte_array();
405
406                                                 let ss = SharedSecret::new(&self.their_node_id.unwrap(), &re.unwrap());
407                                                 let temp_k = PeerChannelEncryptor::hkdf(bidirectional_state, ss);
408
409                                                 PeerChannelEncryptor::decrypt_with_ad(&mut [0; 0], 0, &temp_k, &bidirectional_state.h, &act_three[50..])?;
410                                                 final_hkdf = hkdf_extract_expand_twice(&bidirectional_state.ck, &[0; 0]);
411                                                 ck = bidirectional_state.ck.clone();
412                                         },
413                                         _ => panic!("Wrong direction for act"),
414                                 },
415                         _ => panic!("Cannot get act one after noise handshake completes"),
416                 }
417
418                 let (rk, sk) = final_hkdf;
419                 self.noise_state = NoiseState::Finished {
420                         sk,
421                         sn: 0,
422                         sck: ck.clone(),
423                         rk,
424                         rn: 0,
425                         rck: ck,
426                 };
427
428                 Ok(self.their_node_id.unwrap().clone())
429         }
430
431         /// Builds sendable bytes for a message.
432         ///
433         /// `msgbuf` must begin with 16 + 2 dummy/0 bytes, which will be filled with the encrypted
434         /// message length and its MAC. It should then be followed by the message bytes themselves
435         /// (including the two byte message type).
436         ///
437         /// For effeciency, the [`Vec::capacity`] should be at least 16 bytes larger than the
438         /// [`Vec::len`], to avoid reallocating for the message MAC, which will be appended to the vec.
439         fn encrypt_message_with_header_0s(&mut self, msgbuf: &mut Vec<u8>) {
440                 let msg_len = msgbuf.len() - 16 - 2;
441                 if msg_len > LN_MAX_MSG_LEN {
442                         panic!("Attempted to encrypt message longer than 65535 bytes!");
443                 }
444
445                 match self.noise_state {
446                         NoiseState::Finished { ref mut sk, ref mut sn, ref mut sck, rk: _, rn: _, rck: _ } => {
447                                 if *sn >= 1000 {
448                                         let (new_sck, new_sk) = hkdf_extract_expand_twice(sck, sk);
449                                         *sck = new_sck;
450                                         *sk = new_sk;
451                                         *sn = 0;
452                                 }
453
454                                 Self::encrypt_with_ad(&mut msgbuf[0..16+2], *sn, sk, &[0; 0], &(msg_len as u16).to_be_bytes());
455                                 *sn += 1;
456
457                                 Self::encrypt_in_place_with_ad(msgbuf, 16+2, *sn, sk, &[0; 0]);
458                                 *sn += 1;
459                         },
460                         _ => panic!("Tried to encrypt a message prior to noise handshake completion"),
461                 }
462         }
463
464         /// Encrypts the given pre-serialized message, returning the encrypted version.
465         /// panics if msg.len() > 65535 or Noise handshake has not finished.
466         pub fn encrypt_buffer(&mut self, mut msg: MessageBuf) -> Vec<u8> {
467                 self.encrypt_message_with_header_0s(&mut msg.0);
468                 msg.0
469         }
470
471         /// Encrypts the given message, returning the encrypted version.
472         /// panics if the length of `message`, once encoded, is greater than 65535 or if the Noise
473         /// handshake has not finished.
474         pub fn encrypt_message<M: wire::Type>(&mut self, message: &M) -> Vec<u8> {
475                 // Allocate a buffer with 2KB, fitting most common messages. Reserve the first 16+2 bytes
476                 // for the 2-byte message type prefix and its MAC.
477                 let mut res = VecWriter(Vec::with_capacity(MSG_BUF_ALLOC_SIZE));
478                 res.0.resize(16 + 2, 0);
479                 wire::write(message, &mut res).expect("In-memory messages must never fail to serialize");
480
481                 self.encrypt_message_with_header_0s(&mut res.0);
482                 res.0
483         }
484
485         /// Decrypts a message length header from the remote peer.
486         /// panics if noise handshake has not yet finished or msg.len() != 18
487         pub fn decrypt_length_header(&mut self, msg: &[u8]) -> Result<u16, LightningError> {
488                 assert_eq!(msg.len(), 16+2);
489
490                 match self.noise_state {
491                         NoiseState::Finished { sk: _, sn: _, sck: _, ref mut rk, ref mut rn, ref mut rck } => {
492                                 if *rn >= 1000 {
493                                         let (new_rck, new_rk) = hkdf_extract_expand_twice(rck, rk);
494                                         *rck = new_rck;
495                                         *rk = new_rk;
496                                         *rn = 0;
497                                 }
498
499                                 let mut res = [0; 2];
500                                 Self::decrypt_with_ad(&mut res, *rn, rk, &[0; 0], msg)?;
501                                 *rn += 1;
502                                 Ok(u16::from_be_bytes(res))
503                         },
504                         _ => panic!("Tried to decrypt a message prior to noise handshake completion"),
505                 }
506         }
507
508         /// Decrypts the given message up to msg.len() - 16. Bytes after msg.len() - 16 will be left
509         /// undefined (as they contain the Poly1305 tag bytes).
510         ///
511         /// panics if msg.len() > 65535 + 16
512         pub fn decrypt_message(&mut self, msg: &mut [u8]) -> Result<(), LightningError> {
513                 if msg.len() > LN_MAX_MSG_LEN + 16 {
514                         panic!("Attempted to decrypt message longer than 65535 + 16 bytes!");
515                 }
516
517                 match self.noise_state {
518                         NoiseState::Finished { sk: _, sn: _, sck: _, ref rk, ref mut rn, rck: _ } => {
519                                 Self::decrypt_in_place_with_ad(&mut msg[..], *rn, rk, &[0; 0])?;
520                                 *rn += 1;
521                                 Ok(())
522                         },
523                         _ => panic!("Tried to decrypt a message prior to noise handshake completion"),
524                 }
525         }
526
527         pub fn get_noise_step(&self) -> NextNoiseStep {
528                 match self.noise_state {
529                         NoiseState::InProgress {ref state, ..} => {
530                                 match state {
531                                         &NoiseStep::PreActOne => NextNoiseStep::ActOne,
532                                         &NoiseStep::PostActOne => NextNoiseStep::ActTwo,
533                                         &NoiseStep::PostActTwo => NextNoiseStep::ActThree,
534                                 }
535                         },
536                         NoiseState::Finished {..} => NextNoiseStep::NoiseComplete,
537                 }
538         }
539
540         pub fn is_ready_for_encryption(&self) -> bool {
541                 match self.noise_state {
542                         NoiseState::InProgress {..} => { false },
543                         NoiseState::Finished {..} => { true }
544                 }
545         }
546 }
547
548 /// A buffer which stores an encoded message (including the two message-type bytes) with some
549 /// padding to allow for future encryption/MACing.
550 pub struct MessageBuf(Vec<u8>);
551 impl MessageBuf {
552         /// Creates a new buffer from an encoded message (i.e. the two message-type bytes followed by
553         /// the message contents).
554         ///
555         /// Panics if the message is longer than 2^16.
556         pub fn from_encoded(encoded_msg: &[u8]) -> Self {
557                 if encoded_msg.len() > LN_MAX_MSG_LEN {
558                         panic!("Attempted to encrypt message longer than 65535 bytes!");
559                 }
560                 // In addition to the message (continaing the two message type bytes), we also have to add
561                 // the message length header (and its MAC) and the message MAC.
562                 let mut res = Vec::with_capacity(encoded_msg.len() + 16*2 + 2);
563                 res.resize(encoded_msg.len() + 16 + 2, 0);
564                 res[16 + 2..].copy_from_slice(&encoded_msg);
565                 Self(res)
566         }
567 }
568
569 #[cfg(test)]
570 mod tests {
571         use super::{MessageBuf, LN_MAX_MSG_LEN};
572
573         use bitcoin::hashes::hex::FromHex;
574         use bitcoin::secp256k1::{PublicKey, SecretKey};
575         use bitcoin::secp256k1::Secp256k1;
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(&<Vec<u8>>::from_hex("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(&<Vec<u8>>::from_hex("1212121212121212121212121212121212121212121212121212121212121212").unwrap()[..]).unwrap());
585                 assert_eq!(outbound_peer.get_act_one(&secp_ctx)[..], <Vec<u8>>::from_hex("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(&<Vec<u8>>::from_hex("2121212121212121212121212121212121212121212121212121212121212121").unwrap()[..]).unwrap();
592                 let our_ephemeral = SecretKey::from_slice(&<Vec<u8>>::from_hex("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 = <Vec<u8>>::from_hex("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
599                 assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], <Vec<u8>>::from_hex("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
600
601                 let act_three = <Vec<u8>>::from_hex("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()[..], <Vec<u8>>::from_hex("034f355bdcb7cc0af728ef3cceb9615d90684bb5b2ca5f859ab0f0b704075871aa").unwrap()[..]);
605
606                 match inbound_peer.noise_state {
607                         NoiseState::Finished { sk, sn, sck, rk, rn, rck } => {
608                                 assert_eq!(sk, <Vec<u8>>::from_hex("bb9020b8965f4df047e07f955f3c4b88418984aadc5cdb35096b9ea8fa5c3442").unwrap()[..]);
609                                 assert_eq!(sn, 0);
610                                 assert_eq!(sck, <Vec<u8>>::from_hex("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
611                                 assert_eq!(rk, <Vec<u8>>::from_hex("969ab31b4d288cedf6218839b27a3e2140827047f2c0f01bf5c04435d43511a9").unwrap()[..]);
612                                 assert_eq!(rn, 0);
613                                 assert_eq!(rck, <Vec<u8>>::from_hex("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(&<Vec<u8>>::from_hex("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 = <Vec<u8>>::from_hex("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap().to_vec();
631                         assert_eq!(outbound_peer.process_act_two(&act_two[..], &&node_signer).unwrap().0[..], <Vec<u8>>::from_hex("00b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap()[..]);
632
633                         match outbound_peer.noise_state {
634                                 NoiseState::Finished { sk, sn, sck, rk, rn, rck } => {
635                                         assert_eq!(sk, <Vec<u8>>::from_hex("969ab31b4d288cedf6218839b27a3e2140827047f2c0f01bf5c04435d43511a9").unwrap()[..]);
636                                         assert_eq!(sn, 0);
637                                         assert_eq!(sck, <Vec<u8>>::from_hex("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
638                                         assert_eq!(rk, <Vec<u8>>::from_hex("bb9020b8965f4df047e07f955f3c4b88418984aadc5cdb35096b9ea8fa5c3442").unwrap()[..]);
639                                         assert_eq!(rn, 0);
640                                         assert_eq!(rck, <Vec<u8>>::from_hex("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 = <Vec<u8>>::from_hex("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 = <Vec<u8>>::from_hex("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 = <Vec<u8>>::from_hex("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(&<Vec<u8>>::from_hex("2121212121212121212121212121212121212121212121212121212121212121").unwrap()[..]).unwrap();
677                 let our_ephemeral = SecretKey::from_slice(&<Vec<u8>>::from_hex("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 = <Vec<u8>>::from_hex("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 =<Vec<u8>>::from_hex("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 = <Vec<u8>>::from_hex("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 = <Vec<u8>>::from_hex("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
714                         assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], <Vec<u8>>::from_hex("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
715
716                         let act_three = <Vec<u8>>::from_hex("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 = <Vec<u8>>::from_hex("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
728                         assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], <Vec<u8>>::from_hex("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
729
730                         let act_three = <Vec<u8>>::from_hex("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 = <Vec<u8>>::from_hex("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
738                         assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], <Vec<u8>>::from_hex("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
739
740                         let act_three = <Vec<u8>>::from_hex("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 = <Vec<u8>>::from_hex("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
748                         assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], <Vec<u8>>::from_hex("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
749
750                         let act_three = <Vec<u8>>::from_hex("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(&<Vec<u8>>::from_hex("1111111111111111111111111111111111111111111111111111111111111111").unwrap()[..]).unwrap();
764                         let node_signer = TestNodeSigner::new(our_node_id);
765
766                         let act_two = <Vec<u8>>::from_hex("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap().to_vec();
767                         assert_eq!(outbound_peer.process_act_two(&act_two[..], &&node_signer).unwrap().0[..], <Vec<u8>>::from_hex("00b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap()[..]);
768
769                         match outbound_peer.noise_state {
770                                 NoiseState::Finished { sk, sn, sck, rk, rn, rck } => {
771                                         assert_eq!(sk, <Vec<u8>>::from_hex("969ab31b4d288cedf6218839b27a3e2140827047f2c0f01bf5c04435d43511a9").unwrap()[..]);
772                                         assert_eq!(sn, 0);
773                                         assert_eq!(sck, <Vec<u8>>::from_hex("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
774                                         assert_eq!(rk, <Vec<u8>>::from_hex("bb9020b8965f4df047e07f955f3c4b88418984aadc5cdb35096b9ea8fa5c3442").unwrap()[..]);
775                                         assert_eq!(rn, 0);
776                                         assert_eq!(rck, <Vec<u8>>::from_hex("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, <Vec<u8>>::from_hex("cf2b30ddf0cf3f80e7c35a6e6730b59fe802473180f396d88a8fb0db8cbcf25d2f214cf9ea1d95").unwrap());
794                         } else if i == 1 {
795                                 assert_eq!(res, <Vec<u8>>::from_hex("72887022101f0b6753e0c7de21657d35a4cb2a1f5cde2650528bbc8f837d0f0d7ad833b1a256a1").unwrap());
796                         } else if i == 500 {
797                                 assert_eq!(res, <Vec<u8>>::from_hex("178cb9d7387190fa34db9c2d50027d21793c9bc2d40b1e14dcf30ebeeeb220f48364f7a4c68bf8").unwrap());
798                         } else if i == 501 {
799                                 assert_eq!(res, <Vec<u8>>::from_hex("1b186c57d44eb6de4c057c49940d79bb838a145cb528d6e8fd26dbe50a60ca2c104b56b60e45bd").unwrap());
800                         } else if i == 1000 {
801                                 assert_eq!(res, <Vec<u8>>::from_hex("4a2f3cc3b5e78ddb83dcb426d9863d9d9a723b0337c89dd0b005d89f8d3c05c52b76b29b740f09").unwrap());
802                         } else if i == 1001 {
803                                 assert_eq!(res, <Vec<u8>>::from_hex("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 }