Merge pull request #2828 from TheBlueMatt/2024-01-crypto-module

Move cryptographic algorithms and utilities to a new `crypto` mod

Author: valentinewallace

lightning/src/blinded_path/message.rs

@@ -8,7 +8,7 @@ use crate::ln::onion_utils;
 use crate::onion_message::packet::ControlTlvs;
 use crate::prelude::*;
 use crate::sign::{NodeSigner, Recipient};
-use crate::util::chacha20poly1305rfc::ChaChaPolyReadAdapter;
+use crate::crypto::streams::ChaChaPolyReadAdapter;
 use crate::util::ser::{FixedLengthReader, LengthReadableArgs, Writeable, Writer};
 
 use core::mem;

lightning/src/blinded_path/utils.rs

@@ -19,7 +19,7 @@ use super::{BlindedHop, BlindedPath};
 use crate::ln::msgs::DecodeError;
 use crate::ln::onion_utils;
 use crate::onion_message::messenger::Destination;
-use crate::util::chacha20poly1305rfc::ChaChaPolyWriteAdapter;
+use crate::crypto::streams::ChaChaPolyWriteAdapter;
 use crate::util::ser::{Readable, Writeable};
 
 use crate::io;

lightning/src/chain/channelmonitor.rs

@@ -4808,7 +4808,7 @@ mod tests {
 				preimages_slice_to_htlcs!($preimages_slice).into_iter().map(|(htlc, _)| (htlc, None)).collect()
 			}
 		}
-		let dummy_sig = crate::util::crypto::sign(&secp_ctx,
+		let dummy_sig = crate::crypto::utils::sign(&secp_ctx,
 			&bitcoin::secp256k1::Message::from_slice(&[42; 32]).unwrap(),
 			&SecretKey::from_slice(&[42; 32]).unwrap());
 

lightning/src/util/chacha20.rs renamed to lightning/src/crypto/chacha20.rs

@@ -9,8 +9,6 @@
 // You may not use this file except in accordance with one or both of these
 // licenses.
 
-use crate::io;
-
 #[cfg(not(fuzzing))]
 mod real_chacha {
 	use core::cmp;
@@ -335,27 +333,14 @@ mod fuzzy_chacha {
 #[cfg(fuzzing)]
 pub use self::fuzzy_chacha::ChaCha20;
 
-pub(crate) struct ChaChaReader<'a, R: io::Read> {
-	pub chacha: &'a mut ChaCha20,
-	pub read: R,
-}
-impl<'a, R: io::Read> io::Read for ChaChaReader<'a, R> {
-	fn read(&mut self, dest: &mut [u8]) -> Result<usize, io::Error> {
-		let res = self.read.read(dest)?;
-		if res > 0 {
-			self.chacha.process_in_place(&mut dest[0..res]);
-		}
-		Ok(res)
-	}
-}
-
 #[cfg(test)]
 mod test {
-	use crate::prelude::*;
+	use alloc::vec;
+	use alloc::vec::{Vec};
+	use core::convert::TryInto;
 	use core::iter::repeat;
 
 	use super::ChaCha20;
-	use std::convert::TryInto;
 
 	#[test]
 	fn test_chacha20_256_tls_vectors() {

lightning/src/crypto/chacha20poly1305rfc.rs

@@ -0,0 +1,237 @@
+// ring has a garbage API so its use is avoided, but rust-crypto doesn't have RFC-variant poly1305
+// Instead, we steal rust-crypto's implementation and tweak it to match the RFC.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+//
+// This is a port of Andrew Moons poly1305-donna
+// https://github.com/floodyberry/poly1305-donna
+
+#[cfg(not(fuzzing))]
+mod real_chachapoly {
+	use super::super::chacha20::ChaCha20;
+	use super::super::poly1305::Poly1305;
+	use super::super::fixed_time_eq;
+
+	#[derive(Clone, Copy)]
+	pub struct ChaCha20Poly1305RFC {
+		cipher: ChaCha20,
+		mac: Poly1305,
+		finished: bool,
+		data_len: usize,
+		aad_len: u64,
+	}
+
+	impl ChaCha20Poly1305RFC {
+		#[inline]
+		fn pad_mac_16(mac: &mut Poly1305, len: usize) {
+			if len % 16 != 0 {
+				mac.input(&[0; 16][0..16 - (len % 16)]);
+			}
+		}
+		pub fn new(key: &[u8], nonce: &[u8], aad: &[u8]) -> ChaCha20Poly1305RFC {
+			assert!(key.len() == 16 || key.len() == 32);
+			assert!(nonce.len() == 12);
+
+			// Ehh, I'm too lazy to *also* tweak ChaCha20 to make it RFC-compliant
+			assert!(nonce[0] == 0 && nonce[1] == 0 && nonce[2] == 0 && nonce[3] == 0);
+
+			let mut cipher = ChaCha20::new(key, &nonce[4..]);
+			let mut mac_key = [0u8; 64];
+			let zero_key = [0u8; 64];
+			cipher.process(&zero_key, &mut mac_key);
+
+			let mut mac = Poly1305::new(&mac_key[..32]);
+			mac.input(aad);
+			ChaCha20Poly1305RFC::pad_mac_16(&mut mac, aad.len());
+
+			ChaCha20Poly1305RFC {
+				cipher,
+				mac,
+				finished: false,
+				data_len: 0,
+				aad_len: aad.len() as u64,
+			}
+		}
+
+		pub fn encrypt(&mut self, input: &[u8], output: &mut [u8], out_tag: &mut [u8]) {
+			assert!(input.len() == output.len());
+			assert!(self.finished == false);
+			self.cipher.process(input, output);
+			self.data_len += input.len();
+			self.mac.input(output);
+			ChaCha20Poly1305RFC::pad_mac_16(&mut self.mac, self.data_len);
+			self.finished = true;
+			self.mac.input(&self.aad_len.to_le_bytes());
+			self.mac.input(&(self.data_len as u64).to_le_bytes());
+			self.mac.raw_result(out_tag);
+		}
+
+		pub fn encrypt_full_message_in_place(&mut self, input_output: &mut [u8], out_tag: &mut [u8]) {
+			self.encrypt_in_place(input_output);
+			self.finish_and_get_tag(out_tag);
+		}
+
+		// Encrypt `input_output` in-place. To finish and calculate the tag, use `finish_and_get_tag`
+		// below.
+		pub(in super::super) fn encrypt_in_place(&mut self, input_output: &mut [u8]) {
+			debug_assert!(self.finished == false);
+			self.cipher.process_in_place(input_output);
+			self.data_len += input_output.len();
+			self.mac.input(input_output);
+		}
+
+		// If we were previously encrypting with `encrypt_in_place`, this method can be used to finish
+		// encrypting and calculate the tag.
+		pub(in super::super) fn finish_and_get_tag(&mut self, out_tag: &mut [u8]) {
+			debug_assert!(self.finished == false);
+			ChaCha20Poly1305RFC::pad_mac_16(&mut self.mac, self.data_len);
+			self.finished = true;
+			self.mac.input(&self.aad_len.to_le_bytes());
+			self.mac.input(&(self.data_len as u64).to_le_bytes());
+			self.mac.raw_result(out_tag);
+		}
+
+		/// Decrypt the `input`, checking the given `tag` prior to writing the decrypted contents
+		/// into `output`. Note that, because `output` is not touched until the `tag` is checked,
+		/// this decryption is *variable time*.
+		pub fn variable_time_decrypt(&mut self, input: &[u8], output: &mut [u8], tag: &[u8]) -> Result<(), ()> {
+			assert!(input.len() == output.len());
+			assert!(self.finished == false);
+
+			self.finished = true;
+
+			self.mac.input(input);
+
+			self.data_len += input.len();
+			ChaCha20Poly1305RFC::pad_mac_16(&mut self.mac, self.data_len);
+			self.mac.input(&self.aad_len.to_le_bytes());
+			self.mac.input(&(self.data_len as u64).to_le_bytes());
+
+			let mut calc_tag =  [0u8; 16];
+			self.mac.raw_result(&mut calc_tag);
+			if fixed_time_eq(&calc_tag, tag) {
+				self.cipher.process(input, output);
+				Ok(())
+			} else {
+				Err(())
+			}
+		}
+
+		pub fn check_decrypt_in_place(&mut self, input_output: &mut [u8], tag: &[u8]) -> Result<(), ()> {
+			self.decrypt_in_place(input_output);
+			if self.finish_and_check_tag(tag) { Ok(()) } else { Err(()) }
+		}
+
+		/// Decrypt in place, without checking the tag. Use `finish_and_check_tag` to check it
+		/// later when decryption finishes.
+		///
+		/// Should never be `pub` because the public API should always enforce tag checking.
+		pub(in super::super) fn decrypt_in_place(&mut self, input_output: &mut [u8]) {
+			debug_assert!(self.finished == false);
+			self.mac.input(input_output);
+			self.data_len += input_output.len();
+			self.cipher.process_in_place(input_output);
+		}
+
+		/// If we were previously decrypting with `just_decrypt_in_place`, this method must be used
+		/// to check the tag. Returns whether or not the tag is valid.
+		pub(in super::super) fn finish_and_check_tag(&mut self, tag: &[u8]) -> bool {
+			debug_assert!(self.finished == false);
+			self.finished = true;
+			ChaCha20Poly1305RFC::pad_mac_16(&mut self.mac, self.data_len);
+			self.mac.input(&self.aad_len.to_le_bytes());
+			self.mac.input(&(self.data_len as u64).to_le_bytes());
+
+			let mut calc_tag =  [0u8; 16];
+			self.mac.raw_result(&mut calc_tag);
+			if fixed_time_eq(&calc_tag, tag) {
+				true
+			} else {
+				false
+			}
+		}
+	}
+}
+#[cfg(not(fuzzing))]
+pub use self::real_chachapoly::ChaCha20Poly1305RFC;
+
+#[cfg(fuzzing)]
+mod fuzzy_chachapoly {
+	#[derive(Clone, Copy)]
+	pub struct ChaCha20Poly1305RFC {
+		tag: [u8; 16],
+		finished: bool,
+	}
+	impl ChaCha20Poly1305RFC {
+		pub fn new(key: &[u8], nonce: &[u8], _aad: &[u8]) -> ChaCha20Poly1305RFC {
+			assert!(key.len() == 16 || key.len() == 32);
+			assert!(nonce.len() == 12);
+
+			// Ehh, I'm too lazy to *also* tweak ChaCha20 to make it RFC-compliant
+			assert!(nonce[0] == 0 && nonce[1] == 0 && nonce[2] == 0 && nonce[3] == 0);
+
+			let mut tag = [0; 16];
+			tag.copy_from_slice(&key[0..16]);
+
+			ChaCha20Poly1305RFC {
+				tag,
+				finished: false,
+			}
+		}
+
+		pub fn encrypt(&mut self, input: &[u8], output: &mut [u8], out_tag: &mut [u8]) {
+			assert!(input.len() == output.len());
+			assert!(self.finished == false);
+
+			output.copy_from_slice(&input);
+			out_tag.copy_from_slice(&self.tag);
+			self.finished = true;
+		}
+
+		pub fn encrypt_full_message_in_place(&mut self, input_output: &mut [u8], out_tag: &mut [u8]) {
+			self.encrypt_in_place(input_output);
+			self.finish_and_get_tag(out_tag);
+		}
+
+		pub(in super::super) fn encrypt_in_place(&mut self, _input_output: &mut [u8]) {
+			assert!(self.finished == false);
+		}
+
+		pub(in super::super) fn finish_and_get_tag(&mut self, out_tag: &mut [u8]) {
+			assert!(self.finished == false);
+			out_tag.copy_from_slice(&self.tag);
+			self.finished = true;
+		}
+
+		pub fn variable_time_decrypt(&mut self, input: &[u8], output: &mut [u8], tag: &[u8]) -> Result<(), ()> {
+			assert!(input.len() == output.len());
+			assert!(self.finished == false);
+
+			if tag[..] != self.tag[..] { return Err(()); }
+			output.copy_from_slice(input);
+			self.finished = true;
+			Ok(())
+		}
+
+		pub fn check_decrypt_in_place(&mut self, input_output: &mut [u8], tag: &[u8]) -> Result<(), ()> {
+			self.decrypt_in_place(input_output);
+			if self.finish_and_check_tag(tag) { Ok(()) } else { Err(()) }
+		}
+
+		pub(in super::super) fn decrypt_in_place(&mut self, _input: &mut [u8]) {
+			assert!(self.finished == false);
+		}
+
+		pub(in super::super) fn finish_and_check_tag(&mut self, tag: &[u8]) -> bool {
+			if tag[..] != self.tag[..] { return false; }
+			self.finished = true;
+			true
+		}
+	}
+}
+#[cfg(fuzzing)]
+pub use self::fuzzy_chachapoly::ChaCha20Poly1305RFC;

lightning/src/crypto/mod.rs

@@ -0,0 +1,8 @@
+use bitcoin::hashes::cmp::fixed_time_eq;
+
+pub(crate) mod chacha20;
+#[cfg(not(fuzzing))]
+pub(crate) mod poly1305;
+pub(crate) mod chacha20poly1305rfc;
+pub(crate) mod streams;
+pub(crate) mod utils;

lightning/src/util/poly1305.rs renamed to lightning/src/crypto/poly1305.rs

@@ -205,10 +205,10 @@ impl Poly1305 {
 
 #[cfg(test)]
 mod test {
-	use crate::prelude::*;
 	use core::iter::repeat;
+	use alloc::vec::Vec;
 
-	use crate::util::poly1305::Poly1305;
+	use super::Poly1305;
 
 	fn poly1305(key: &[u8], msg: &[u8], mac: &mut [u8]) {
 		let mut poly = Poly1305::new(key);