// This is a port of Andrew Moons poly1305-donna
// https://github.com/floodyberry/poly1305-donna
-use util::ser::{Writeable, Writer};
-use io::{self, Write};
+use ln::msgs::DecodeError;
+use util::ser::{FixedLengthReader, LengthRead, LengthReadableArgs, Readable, Writeable, Writer};
+use io::{self, Read, Write};
#[cfg(not(fuzzing))]
mod real_chachapoly {
false
}
}
+
+ // 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(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 `decrypt_in_place`, this method must be used to finish
+ // decrypting and check the tag. Returns whether or not the tag is valid.
+ pub(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;
+/// Enables simultaneously reading and decrypting a ChaCha20Poly1305RFC stream from a std::io::Read.
+struct ChaChaPolyReader<'a, R: Read> {
+ pub chacha: &'a mut ChaCha20Poly1305RFC,
+ pub read: R,
+}
+
+impl<'a, R: Read> Read for ChaChaPolyReader<'a, R> {
+ // Decrypt bytes from Self::read into `dest`.
+ // `ChaCha20Poly1305RFC::finish_and_check_tag` must be called to check the tag after all reads
+ // complete.
+ fn read(&mut self, dest: &mut [u8]) -> Result<usize, io::Error> {
+ let res = self.read.read(dest)?;
+ if res > 0 {
+ self.chacha.decrypt_in_place(&mut dest[0..res]);
+ }
+ Ok(res)
+ }
+}
+
/// Enables simultaneously writing and encrypting a byte stream into a Writer.
struct ChaChaPolyWriter<'a, W: Writer> {
pub chacha: &'a mut ChaCha20Poly1305RFC,
}
}
+/// Enables the use of the serialization macros for objects that need to be simultaneously decrypted and
+/// deserialized. This allows us to avoid an intermediate Vec allocation.
+pub(crate) struct ChaChaPolyReadAdapter<R: Readable> {
+ #[allow(unused)] // This will be used soon for onion messages
+ pub readable: R,
+}
+
+impl<T: Readable> LengthReadableArgs<[u8; 32]> for ChaChaPolyReadAdapter<T> {
+ // Simultaneously read and decrypt an object from a LengthRead, storing it in Self::readable.
+ // LengthRead must be used instead of std::io::Read because we need the total length to separate
+ // out the tag at the end.
+ fn read<R: LengthRead>(mut r: &mut R, secret: [u8; 32]) -> Result<Self, DecodeError> {
+ if r.total_bytes() < 16 { return Err(DecodeError::InvalidValue) }
+
+ let mut chacha = ChaCha20Poly1305RFC::new(&secret, &[0; 12], &[]);
+ let decrypted_len = r.total_bytes() - 16;
+ let s = FixedLengthReader::new(&mut r, decrypted_len);
+ let mut chacha_stream = ChaChaPolyReader { chacha: &mut chacha, read: s };
+ let readable: T = Readable::read(&mut chacha_stream)?;
+ chacha_stream.read.eat_remaining()?;
+
+ let mut tag = [0 as u8; 16];
+ r.read_exact(&mut tag)?;
+ if !chacha.finish_and_check_tag(&tag) {
+ return Err(DecodeError::InvalidValue)
+ }
+
+ Ok(Self { readable })
+ }
+}
+
#[cfg(fuzzing)]
mod fuzzy_chachapoly {
#[derive(Clone, Copy)]
self.finished = true;
true
}
+
+ pub(super) fn decrypt_in_place(&mut self, _input: &mut [u8]) {
+ assert!(self.finished == false);
+ }
+
+ pub(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;
+
+#[cfg(test)]
+mod tests {
+ use ln::msgs::DecodeError;
+ use super::{ChaChaPolyReadAdapter, ChaChaPolyWriteAdapter};
+ use util::ser::{self, FixedLengthReader, LengthReadableArgs, Writeable};
+
+ // Used for for testing various lengths of serialization.
+ #[derive(Debug, PartialEq)]
+ struct TestWriteable {
+ field1: Vec<u8>,
+ field2: Vec<u8>,
+ field3: Vec<u8>,
+ }
+ impl_writeable_tlv_based!(TestWriteable, {
+ (1, field1, vec_type),
+ (2, field2, vec_type),
+ (3, field3, vec_type),
+ });
+
+ #[test]
+ fn test_chacha_stream_adapters() {
+ // Check that ChaChaPolyReadAdapter and ChaChaPolyWriteAdapter correctly encode and decode an
+ // encrypted object.
+ macro_rules! check_object_read_write {
+ ($obj: expr) => {
+ // First, serialize the object, encrypted with ChaCha20Poly1305.
+ let rho = [42; 32];
+ let writeable_len = $obj.serialized_length() as u64 + 16;
+ let write_adapter = ChaChaPolyWriteAdapter::new(rho, &$obj);
+ let encrypted_writeable_bytes = write_adapter.encode();
+ let encrypted_writeable = &encrypted_writeable_bytes[..];
+
+ // Now deserialize the object back and make sure it matches the original.
+ let mut rd = FixedLengthReader::new(encrypted_writeable, writeable_len);
+ let read_adapter = <ChaChaPolyReadAdapter<TestWriteable>>::read(&mut rd, rho).unwrap();
+ assert_eq!($obj, read_adapter.readable);
+ };
+ }
+
+ // Try a big object that will require multiple write buffers.
+ let big_writeable = TestWriteable {
+ field1: vec![43],
+ field2: vec![44; 4192],
+ field3: vec![45; 4192 + 1],
+ };
+ check_object_read_write!(big_writeable);
+
+ // Try a small object that fits into one write buffer.
+ let small_writeable = TestWriteable {
+ field1: vec![43],
+ field2: vec![44],
+ field3: vec![45],
+ };
+ check_object_read_write!(small_writeable);
+ }
+
+ fn do_chacha_stream_adapters_ser_macros() -> Result<(), DecodeError> {
+ let writeable = TestWriteable {
+ field1: vec![43],
+ field2: vec![44; 4192],
+ field3: vec![45; 4192 + 1],
+ };
+
+ // First, serialize the object into a TLV stream, encrypted with ChaCha20Poly1305.
+ let rho = [42; 32];
+ let write_adapter = ChaChaPolyWriteAdapter::new(rho, &writeable);
+ let mut writer = ser::VecWriter(Vec::new());
+ encode_tlv_stream!(&mut writer, {
+ (1, write_adapter, required),
+ });
+
+ // Now deserialize the object back and make sure it matches the original.
+ let mut read_adapter: Option<ChaChaPolyReadAdapter<TestWriteable>> = None;
+ decode_tlv_stream!(&writer.0[..], {
+ (1, read_adapter, (option: LengthReadableArgs, rho)),
+ });
+ assert_eq!(writeable, read_adapter.unwrap().readable);
+
+ Ok(())
+ }
+
+ #[test]
+ fn chacha_stream_adapters_ser_macros() {
+ // Test that our stream adapters work as expected with the TLV macros.
+ // This also serves to test the `option: $trait` variant of the `decode_tlv` ser macro.
+ do_chacha_stream_adapters_ser_macros().unwrap()
+ }
+}
projects / rust-lightning / commitdiff