_ Git - rust-lightning/blob - lightning/src/crypto/streams.rs

   1 use crate::crypto::chacha20::ChaCha20;
   2 use crate::crypto::chacha20poly1305rfc::ChaCha20Poly1305RFC;
   3
   4 use crate::ln::msgs::DecodeError;
   5 use crate::util::ser::{FixedLengthReader, LengthRead, LengthReadableArgs, Readable, Writeable, Writer};
   6 use crate::io::{self, Read, Write};
   7
   8 pub(crate) struct ChaChaReader<'a, R: io::Read> {
   9         pub chacha: &'a mut ChaCha20,
  10         pub read: R,
  11 }
  12 impl<'a, R: io::Read> io::Read for ChaChaReader<'a, R> {
  13         fn read(&mut self, dest: &mut [u8]) -> Result<usize, io::Error> {
  14                 let res = self.read.read(dest)?;
  15                 if res > 0 {
  16                         self.chacha.process_in_place(&mut dest[0..res]);
  17                 }
  18                 Ok(res)
  19         }
  20 }
  21
  22 /// Enables the use of the serialization macros for objects that need to be simultaneously encrypted and
  23 /// serialized. This allows us to avoid an intermediate Vec allocation.
  24 pub(crate) struct ChaChaPolyWriteAdapter<'a, W: Writeable> {
  25         pub rho: [u8; 32],
  26         pub writeable: &'a W,
  27 }
  28
  29 impl<'a, W: Writeable> ChaChaPolyWriteAdapter<'a, W> {
  30         #[allow(unused)] // This will be used for onion messages soon
  31         pub fn new(rho: [u8; 32], writeable: &'a W) -> ChaChaPolyWriteAdapter<'a, W> {
  32                 Self { rho, writeable }
  33         }
  34 }
  35
  36 impl<'a, T: Writeable> Writeable for ChaChaPolyWriteAdapter<'a, T> {
  37         // Simultaneously write and encrypt Self::writeable.
  38         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
  39                 let mut chacha = ChaCha20Poly1305RFC::new(&self.rho, &[0; 12], &[]);
  40                 let mut chacha_stream = ChaChaPolyWriter { chacha: &mut chacha, write: w };
  41                 self.writeable.write(&mut chacha_stream)?;
  42                 let mut tag = [0 as u8; 16];
  43                 chacha.finish_and_get_tag(&mut tag);
  44                 tag.write(w)?;
  45
  46                 Ok(())
  47         }
  48 }
  49
  50 /// Enables the use of the serialization macros for objects that need to be simultaneously decrypted and
  51 /// deserialized. This allows us to avoid an intermediate Vec allocation.
  52 pub(crate) struct ChaChaPolyReadAdapter<R: Readable> {
  53         pub readable: R,
  54 }
  55
  56 impl<T: Readable> LengthReadableArgs<[u8; 32]> for ChaChaPolyReadAdapter<T> {
  57         // Simultaneously read and decrypt an object from a LengthRead, storing it in Self::readable.
  58         // LengthRead must be used instead of std::io::Read because we need the total length to separate
  59         // out the tag at the end.
  60         fn read<R: LengthRead>(mut r: &mut R, secret: [u8; 32]) -> Result<Self, DecodeError> {
  61                 if r.total_bytes() < 16 { return Err(DecodeError::InvalidValue) }
  62
  63                 let mut chacha = ChaCha20Poly1305RFC::new(&secret, &[0; 12], &[]);
  64                 let decrypted_len = r.total_bytes() - 16;
  65                 let s = FixedLengthReader::new(&mut r, decrypted_len);
  66                 let mut chacha_stream = ChaChaPolyReader { chacha: &mut chacha, read: s };
  67                 let readable: T = Readable::read(&mut chacha_stream)?;
  68                 chacha_stream.read.eat_remaining()?;
  69
  70                 let mut tag = [0 as u8; 16];
  71                 r.read_exact(&mut tag)?;
  72                 if !chacha.finish_and_check_tag(&tag) {
  73                         return Err(DecodeError::InvalidValue)
  74                 }
  75
  76                 Ok(Self { readable })
  77         }
  78 }
  79
  80
  81 /// Enables simultaneously reading and decrypting a ChaCha20Poly1305RFC stream from a std::io::Read.
  82 struct ChaChaPolyReader<'a, R: Read> {
  83         pub chacha: &'a mut ChaCha20Poly1305RFC,
  84         pub read: R,
  85 }
  86
  87 impl<'a, R: Read> Read for ChaChaPolyReader<'a, R> {
  88         // Decrypt bytes from Self::read into `dest`.
  89         // `ChaCha20Poly1305RFC::finish_and_check_tag` must be called to check the tag after all reads
  90         // complete.
  91         fn read(&mut self, dest: &mut [u8]) -> Result<usize, io::Error> {
  92                 let res = self.read.read(dest)?;
  93                 if res > 0 {
  94                         self.chacha.decrypt_in_place(&mut dest[0..res]);
  95                 }
  96                 Ok(res)
  97         }
  98 }
  99
 100 /// Enables simultaneously writing and encrypting a byte stream into a Writer.
 101 struct ChaChaPolyWriter<'a, W: Writer> {
 102         pub chacha: &'a mut ChaCha20Poly1305RFC,
 103         pub write: &'a mut W,
 104 }
 105
 106 impl<'a, W: Writer> Writer for ChaChaPolyWriter<'a, W> {
 107         // Encrypt then write bytes from `src` into Self::write.
 108         // `ChaCha20Poly1305RFC::finish_and_get_tag` can be called to retrieve the tag after all writes
 109         // complete.
 110         fn write_all(&mut self, src: &[u8]) -> Result<(), io::Error> {
 111                 let mut src_idx = 0;
 112                 while src_idx < src.len() {
 113                         let mut write_buffer = [0; 8192];
 114                         let bytes_written = (&mut write_buffer[..]).write(&src[src_idx..]).expect("In-memory writes can't fail");
 115                         self.chacha.encrypt_in_place(&mut write_buffer[..bytes_written]);
 116                         self.write.write_all(&write_buffer[..bytes_written])?;
 117                         src_idx += bytes_written;
 118                 }
 119                 Ok(())
 120         }
 121 }
 122
 123
 124 #[cfg(test)]
 125 mod tests {
 126         use crate::ln::msgs::DecodeError;
 127         use super::{ChaChaPolyReadAdapter, ChaChaPolyWriteAdapter};
 128         use crate::util::ser::{self, FixedLengthReader, LengthReadableArgs, Writeable};
 129
 130         // Used for for testing various lengths of serialization.
 131         #[derive(Debug, PartialEq, Eq)]
 132         struct TestWriteable {
 133                 field1: Vec<u8>,
 134                 field2: Vec<u8>,
 135                 field3: Vec<u8>,
 136         }
 137         impl_writeable_tlv_based!(TestWriteable, {
 138                 (1, field1, required_vec),
 139                 (2, field2, required_vec),
 140                 (3, field3, required_vec),
 141         });
 142
 143         #[test]
 144         fn test_chacha_stream_adapters() {
 145                 // Check that ChaChaPolyReadAdapter and ChaChaPolyWriteAdapter correctly encode and decode an
 146                 // encrypted object.
 147                 macro_rules! check_object_read_write {
 148                         ($obj: expr) => {
 149                                 // First, serialize the object, encrypted with ChaCha20Poly1305.
 150                                 let rho = [42; 32];
 151                                 let writeable_len = $obj.serialized_length() as u64 + 16;
 152                                 let write_adapter = ChaChaPolyWriteAdapter::new(rho, &$obj);
 153                                 let encrypted_writeable_bytes = write_adapter.encode();
 154                                 let encrypted_writeable = &encrypted_writeable_bytes[..];
 155
 156                                 // Now deserialize the object back and make sure it matches the original.
 157                                 let mut rd = FixedLengthReader::new(encrypted_writeable, writeable_len);
 158                                 let read_adapter = <ChaChaPolyReadAdapter<TestWriteable>>::read(&mut rd, rho).unwrap();
 159                                 assert_eq!($obj, read_adapter.readable);
 160                         };
 161                 }
 162
 163                 // Try a big object that will require multiple write buffers.
 164                 let big_writeable = TestWriteable {
 165                         field1: vec![43],
 166                         field2: vec![44; 4192],
 167                         field3: vec![45; 4192 + 1],
 168                 };
 169                 check_object_read_write!(big_writeable);
 170
 171                 // Try a small object that fits into one write buffer.
 172                 let small_writeable = TestWriteable {
 173                         field1: vec![43],
 174                         field2: vec![44],
 175                         field3: vec![45],
 176                 };
 177                 check_object_read_write!(small_writeable);
 178         }
 179
 180         fn do_chacha_stream_adapters_ser_macros() -> Result<(), DecodeError> {
 181                 let writeable = TestWriteable {
 182                         field1: vec![43],
 183                         field2: vec![44; 4192],
 184                         field3: vec![45; 4192 + 1],
 185                 };
 186
 187                 // First, serialize the object into a TLV stream, encrypted with ChaCha20Poly1305.
 188                 let rho = [42; 32];
 189                 let write_adapter = ChaChaPolyWriteAdapter::new(rho, &writeable);
 190                 let mut writer = ser::VecWriter(Vec::new());
 191                 encode_tlv_stream!(&mut writer, {
 192                         (1, write_adapter, required),
 193                 });
 194
 195                 // Now deserialize the object back and make sure it matches the original.
 196                 let mut read_adapter: Option<ChaChaPolyReadAdapter<TestWriteable>> = None;
 197                 decode_tlv_stream!(&writer.0[..], {
 198                         (1, read_adapter, (option: LengthReadableArgs, rho)),
 199                 });
 200                 assert_eq!(writeable, read_adapter.unwrap().readable);
 201
 202                 Ok(())
 203         }
 204
 205         #[test]
 206         fn chacha_stream_adapters_ser_macros() {
 207                 // Test that our stream adapters work as expected with the TLV macros.
 208                 // This also serves to test the `option: $trait` variant of the `_decode_tlv` ser macro.
 209                 do_chacha_stream_adapters_ser_macros().unwrap()
 210         }
 211 }