use std::io;
use std::cmp;
use std::fmt;
use crate::Result;
use crate::SymmetricAlgorithm;
use crate::vec_truncate;
use buffered_reader::BufferedReader;
pub(crate) trait Mode: Send + Sync {
fn block_size(&self) -> usize;
fn encrypt(
&mut self,
dst: &mut [u8],
src: &[u8],
) -> Result<()>;
fn decrypt(
&mut self,
dst: &mut [u8],
src: &[u8],
) -> Result<()>;
}
pub struct Decryptor<R: io::Read> {
source: R,
dec: Box<dyn Mode>,
block_size: usize,
buffer: Vec<u8>,
}
assert_send_and_sync!(Decryptor<R> where R: io::Read);
impl<R: io::Read> Decryptor<R> {
pub fn new(algo: SymmetricAlgorithm, key: &[u8], source: R) -> Result<Self> {
let block_size = algo.block_size()?;
let iv = vec![0; block_size];
let dec = algo.make_decrypt_cfb(key, iv)?;
Ok(Decryptor {
source,
dec,
block_size,
buffer: Vec::with_capacity(block_size),
})
}
}
fn read_exact<R: io::Read>(reader: &mut R, mut buffer: &mut [u8])
-> io::Result<usize>
{
let mut read = 0;
while !buffer.is_empty() {
match reader.read(buffer) {
Ok(0) => break,
Ok(n) => {
read += n;
let tmp = buffer;
buffer = &mut tmp[n..];
},
Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
Err(e) => {
if read > 0 {
return Ok(read);
} else {
return Err(e);
}
},
}
}
Ok(read)
}
impl<R: io::Read> io::Read for Decryptor<R> {
fn read(&mut self, plaintext: &mut [u8]) -> io::Result<usize> {
let mut pos = 0;
if self.buffer.len() > 0 {
let to_copy = cmp::min(self.buffer.len(), plaintext.len());
&plaintext[..to_copy].copy_from_slice(&self.buffer[..to_copy]);
crate::vec_drain_prefix(&mut self.buffer, to_copy);
pos = to_copy;
}
if pos == plaintext.len() {
return Ok(pos);
}
let mut to_copy
= ((plaintext.len() - pos) / self.block_size) * self.block_size;
let mut ciphertext = vec![0u8; to_copy];
let result = read_exact(&mut self.source, &mut ciphertext[..]);
let short_read;
match result {
Ok(amount) => {
short_read = amount < to_copy;
to_copy = amount;
vec_truncate(&mut ciphertext, to_copy);
},
Err(_) if pos > 0 => return Ok(pos),
Err(e) => return Err(e),
}
self.dec.decrypt(&mut plaintext[pos..pos + to_copy],
&ciphertext[..])
.map_err(|e| io::Error::new(io::ErrorKind::InvalidInput,
format!("{}", e)))?;
pos += to_copy;
if short_read || pos == plaintext.len() {
return Ok(pos);
}
let mut to_copy = plaintext.len() - pos;
assert!(0 < to_copy);
assert!(to_copy < self.block_size);
let mut ciphertext = vec![0u8; self.block_size];
let result = read_exact(&mut self.source, &mut ciphertext[..]);
match result {
Ok(amount) => {
vec_truncate(&mut ciphertext, amount);
to_copy = cmp::min(to_copy, ciphertext.len());
},
Err(_) if pos > 0 => return Ok(pos),
Err(e) => return Err(e),
}
assert!(ciphertext.len() <= self.block_size);
while self.buffer.len() < ciphertext.len() {
self.buffer.push(0u8);
}
vec_truncate(&mut self.buffer, ciphertext.len());
self.dec.decrypt(&mut self.buffer, &ciphertext[..])
.map_err(|e| io::Error::new(io::ErrorKind::InvalidInput,
format!("{}", e)))?;
&plaintext[pos..pos + to_copy].copy_from_slice(&self.buffer[..to_copy]);
crate::vec_drain_prefix(&mut self.buffer, to_copy);
pos += to_copy;
Ok(pos)
}
}
pub(crate) struct BufferedReaderDecryptor<R: BufferedReader<C>, C: fmt::Debug + Send + Sync> {
reader: buffered_reader::Generic<Decryptor<R>, C>,
}
impl <R: BufferedReader<C>, C: fmt::Debug + Send + Sync> BufferedReaderDecryptor<R, C> {
pub fn with_cookie(algo: SymmetricAlgorithm, key: &[u8], reader: R,
cookie: C)
-> Result<Self>
{
Ok(BufferedReaderDecryptor {
reader: buffered_reader::Generic::with_cookie(
Decryptor::new(algo, key, reader)?, None, cookie),
})
}
}
impl<R: BufferedReader<C>, C: fmt::Debug + Send + Sync> io::Read for BufferedReaderDecryptor<R, C> {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
self.reader.read(buf)
}
}
impl<R: BufferedReader<C>, C: fmt::Debug + Send + Sync> fmt::Display for BufferedReaderDecryptor<R, C> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "BufferedReaderDecryptor")
}
}
impl<R: BufferedReader<C>, C: fmt::Debug + Send + Sync> fmt::Debug for BufferedReaderDecryptor<R, C> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.debug_struct("BufferedReaderDecryptor")
.field("reader", &self.get_ref().unwrap())
.finish()
}
}
impl<R: BufferedReader<C>, C: fmt::Debug + Send + Sync> BufferedReader<C>
for BufferedReaderDecryptor<R, C> {
fn buffer(&self) -> &[u8] {
return self.reader.buffer();
}
fn data(&mut self, amount: usize) -> io::Result<&[u8]> {
return self.reader.data(amount);
}
fn data_hard(&mut self, amount: usize) -> io::Result<&[u8]> {
return self.reader.data_hard(amount);
}
fn data_eof(&mut self) -> io::Result<&[u8]> {
return self.reader.data_eof();
}
fn consume(&mut self, amount: usize) -> &[u8] {
return self.reader.consume(amount);
}
fn data_consume(&mut self, amount: usize)
-> io::Result<&[u8]> {
return self.reader.data_consume(amount);
}
fn data_consume_hard(&mut self, amount: usize) -> io::Result<&[u8]> {
return self.reader.data_consume_hard(amount);
}
fn read_be_u16(&mut self) -> io::Result<u16> {
return self.reader.read_be_u16();
}
fn read_be_u32(&mut self) -> io::Result<u32> {
return self.reader.read_be_u32();
}
fn steal(&mut self, amount: usize) -> io::Result<Vec<u8>> {
return self.reader.steal(amount);
}
fn steal_eof(&mut self) -> io::Result<Vec<u8>> {
return self.reader.steal_eof();
}
fn get_mut(&mut self) -> Option<&mut dyn BufferedReader<C>> {
Some(&mut self.reader.reader_mut().source)
}
fn get_ref(&self) -> Option<&dyn BufferedReader<C>> {
Some(&self.reader.reader_ref().source)
}
fn into_inner<'b>(self: Box<Self>)
-> Option<Box<dyn BufferedReader<C> + 'b>> where Self: 'b {
Some(self.reader.into_reader().source.as_boxed())
}
fn cookie_set(&mut self, cookie: C) -> C {
self.reader.cookie_set(cookie)
}
fn cookie_ref(&self) -> &C {
self.reader.cookie_ref()
}
fn cookie_mut(&mut self) -> &mut C {
self.reader.cookie_mut()
}
}
pub struct Encryptor<W: io::Write> {
inner: Option<W>,
cipher: Box<dyn Mode>,
block_size: usize,
buffer: Vec<u8>,
scratch: Vec<u8>,
}
assert_send_and_sync!(Encryptor<W> where W: io::Write);
impl<W: io::Write> Encryptor<W> {
pub fn new(algo: SymmetricAlgorithm, key: &[u8], sink: W) -> Result<Self> {
let block_size = algo.block_size()?;
let iv = vec![0; block_size];
let cipher = algo.make_encrypt_cfb(key, iv)?;
let mut scratch = Vec::with_capacity(block_size);
unsafe { scratch.set_len(block_size); }
Ok(Encryptor {
inner: Some(sink),
cipher,
block_size,
buffer: Vec::with_capacity(block_size),
scratch,
})
}
pub fn finish(&mut self) -> Result<W> {
if let Some(mut inner) = self.inner.take() {
if self.buffer.len() > 0 {
unsafe { self.scratch.set_len(self.buffer.len()) }
self.cipher.encrypt(&mut self.scratch, &self.buffer)?;
crate::vec_truncate(&mut self.buffer, 0);
inner.write_all(&self.scratch)?;
}
Ok(inner)
} else {
Err(io::Error::new(io::ErrorKind::BrokenPipe,
"Inner writer was taken").into())
}
}
pub fn get_ref(&self) -> Option<&W> {
self.inner.as_ref()
}
#[allow(dead_code)]
pub fn get_mut(&mut self) -> Option<&mut W> {
self.inner.as_mut()
}
}
impl<W: io::Write> io::Write for Encryptor<W> {
fn write(&mut self, mut buf: &[u8]) -> io::Result<usize> {
if self.inner.is_none() {
return Err(io::Error::new(io::ErrorKind::BrokenPipe,
"Inner writer was taken"));
}
let inner = self.inner.as_mut().unwrap();
let amount = buf.len();
if self.buffer.len() > 0 {
let n = cmp::min(buf.len(), self.block_size - self.buffer.len());
self.buffer.extend_from_slice(&buf[..n]);
assert!(self.buffer.len() <= self.block_size);
buf = &buf[n..];
if self.buffer.len() == self.block_size {
self.cipher.encrypt(&mut self.scratch, &self.buffer)
.map_err(|e| io::Error::new(io::ErrorKind::InvalidInput,
format!("{}", e)))?;
crate::vec_truncate(&mut self.buffer, 0);
inner.write_all(&self.scratch)?;
}
}
for block in buf.chunks(self.block_size) {
if block.len() == self.block_size {
self.cipher.encrypt(&mut self.scratch, block)
.map_err(|e| io::Error::new(io::ErrorKind::InvalidInput,
format!("{}", e)))?;
inner.write_all(&self.scratch)?;
} else {
assert!(self.buffer.is_empty());
self.buffer.extend_from_slice(block);
}
}
Ok(amount)
}
fn flush(&mut self) -> io::Result<()> {
if let Some(ref mut inner) = self.inner {
inner.flush()
} else {
Err(io::Error::new(io::ErrorKind::BrokenPipe,
"Inner writer was taken"))
}
}
}
impl<W: io::Write> Drop for Encryptor<W> {
fn drop(&mut self) {
let _ = self.finish();
}
}
#[cfg(test)]
mod tests {
use super::*;
use std::io::{Cursor, Read, Write};
#[test]
fn smoke_test() {
use crate::fmt::hex;
let algo = SymmetricAlgorithm::AES128;
let key = &hex::decode("2b7e151628aed2a6abf7158809cf4f3c").unwrap();
assert_eq!(key.len(), 16);
let iv = hex::decode("000102030405060708090A0B0C0D0E0F").unwrap();
let mut cfb = algo.make_encrypt_cfb(&key, iv).unwrap();
let msg = hex::decode("6bc1bee22e409f96e93d7e117393172a").unwrap();
let mut dst = vec![0; msg.len()];
cfb.encrypt(&mut dst, &*msg).unwrap();
assert_eq!(&dst[..16], &*hex::decode("3b3fd92eb72dad20333449f8e83cfb4a").unwrap());
let iv = hex::decode("000102030405060708090A0B0C0D0E0F").unwrap();
let mut cfb = algo.make_encrypt_cfb(&key, iv).unwrap();
let msg = b"This is a very important message";
let mut dst = vec![0; msg.len()];
cfb.encrypt(&mut dst, &*msg).unwrap();
assert_eq!(&dst, &hex::decode(
"04960ebfb9044196bb29418ce9d6cc0939d5ccb1d0712fa8e45fe5673456fded"
).unwrap());
let iv = hex::decode("000102030405060708090A0B0C0D0E0F").unwrap();
let mut cfb = algo.make_encrypt_cfb(&key, iv).unwrap();
let msg = b"This is a very important message!";
let mut dst = vec![0; msg.len()];
cfb.encrypt(&mut dst, &*msg).unwrap();
assert_eq!(&dst, &hex::decode(
"04960ebfb9044196bb29418ce9d6cc0939d5ccb1d0712fa8e45fe5673456fded0b"
).unwrap());
let iv = hex::decode("000102030405060708090A0B0C0D0E0F").unwrap();
let mut cfb = algo.make_encrypt_cfb(&key, iv).unwrap();
let mut dst = vec![0; msg.len()];
for (mut dst, msg) in dst.chunks_mut(16).zip(msg.chunks(16)) {
cfb.encrypt(&mut dst, msg).unwrap();
}
assert_eq!(&dst, &hex::decode(
"04960ebfb9044196bb29418ce9d6cc0939d5ccb1d0712fa8e45fe5673456fded0b"
).unwrap());
}
#[test]
fn decryptor() {
for algo in [SymmetricAlgorithm::AES128,
SymmetricAlgorithm::AES192,
SymmetricAlgorithm::AES256].iter() {
let mut key = vec![0u8; algo.key_size().unwrap()];
for i in 0..key.len() {
key[0] = i as u8;
}
let filename = &format!(
"raw/a-cypherpunks-manifesto.aes{}.key_ascending_from_0",
algo.key_size().unwrap() * 8);
let ciphertext = Cursor::new(crate::tests::file(filename));
let decryptor = Decryptor::new(*algo, &key, ciphertext).unwrap();
let mut plaintext = Vec::new();
for b in decryptor.bytes() {
plaintext.push(b.unwrap());
}
assert_eq!(crate::tests::manifesto(), &plaintext[..]);
}
}
#[test]
fn encryptor() {
for algo in [SymmetricAlgorithm::AES128,
SymmetricAlgorithm::AES192,
SymmetricAlgorithm::AES256].iter() {
let mut key = vec![0u8; algo.key_size().unwrap()];
for i in 0..key.len() {
key[0] = i as u8;
}
let mut ciphertext = Vec::new();
{
let mut encryptor = Encryptor::new(*algo, &key, &mut ciphertext)
.unwrap();
for b in crate::tests::manifesto().chunks(1) {
encryptor.write_all(b).unwrap();
}
}
let filename = format!(
"raw/a-cypherpunks-manifesto.aes{}.key_ascending_from_0",
algo.key_size().unwrap() * 8);
let mut cipherfile = Cursor::new(crate::tests::file(&filename));
let mut reference = Vec::new();
cipherfile.read_to_end(&mut reference).unwrap();
assert_eq!(&reference[..], &ciphertext[..]);
}
}
#[test]
fn roundtrip() {
use std::io::Cursor;
for algo in [SymmetricAlgorithm::TripleDES,
SymmetricAlgorithm::CAST5,
SymmetricAlgorithm::Blowfish,
SymmetricAlgorithm::AES128,
SymmetricAlgorithm::AES192,
SymmetricAlgorithm::AES256,
SymmetricAlgorithm::Twofish,
SymmetricAlgorithm::Camellia128,
SymmetricAlgorithm::Camellia192,
SymmetricAlgorithm::Camellia256]
.iter()
.filter(|x| x.is_supported()) {
let mut key = vec![0; algo.key_size().unwrap()];
crate::crypto::random(&mut key);
let mut ciphertext = Vec::new();
{
let mut encryptor = Encryptor::new(*algo, &key, &mut ciphertext)
.unwrap();
encryptor.write_all(crate::tests::manifesto()).unwrap();
}
let mut plaintext = Vec::new();
{
let mut decryptor = Decryptor::new(*algo, &key,
Cursor::new(&mut ciphertext))
.unwrap();
decryptor.read_to_end(&mut plaintext).unwrap();
}
assert_eq!(&plaintext[..], &crate::tests::manifesto()[..]);
}
}
}