why a vec? why not a fixed size array?
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buf: RefCell<Vec>,
/// tracks how much encrypted data is left in the reader
bytes_in_reader: RefCell,
/// buf_ptr tracks the current position in the buffer- where to start reading decrypted data from
buf_ptr: RefCell,
/// bytes_in_buffer tracks how many bytes are in the buffer- it may not always be full
bytes_in_buffer: RefCell,
/// Writer to another file
reader: RefCell,
/// Decryptor. This stores the key
decryptor: RefCell<Decryptor<Aes256Gcm, StreamBE32>>,
/// Counter of bytes read from this struct's read() method
bytes_read: RefCell,
/// buffer to eventually put the tag into
tag_buf: RefCell<[u8; TAG_SIZE]>,
/// should we finalize the decryption? this means tag_buf will be filled with the tag and bytes_in_reader will be 0
finalize: RefCell,
}
/// A wrapper around a reader that decrypts the data as it is written.
impl<R: Read + Unpin + Seek> DecryptionReader {
/// Create a new DecryptionReader.
///
/// # Arguments
/// reader: The reader to read encrypted data from. should start with the nonce.
/// key_and_nonce: The key and nonce to use for decryption.
///
/// # Returns
/// A DecryptionReader
pub async fn new(mut reader: R, key_and_nonce: KeyAndNonceToDisk) -> Result {
let KeyAndNonce { key, nonce } = *key_and_nonce.consume_and_prep_from_disk()?;
let cipher = Aes256Gcm::new(&key);
let decryptor = RefCell::new(StreamBE32::from_aead(cipher, &nonce).decryptor());
let file_len = reader.seek(SeekFrom::End(0))?;
reader.seek(SeekFrom::Start(0))?;
Ok(Self {
buf: RefCell::new(vec![]),
tag_buf: RefCell::new([0; TAG_SIZE]),
bytes_in_reader: RefCell::new(file_len as usize - TAG_SIZE),
bytes_in_buffer: RefCell::new(0),
buf_ptr: RefCell::new(0),
reader: reader.into(),
decryptor,
bytes_read: RefCell::new(0),
finalize: RefCell::new(false),
})
}
/// Read from the Reader into the buffer, decrypting it in place.
pub async fn refresh_buffer(&mut self) -> std::io::Result<()> {
println!("Refreshing buffer");
// Borrow the mutable references to the fields we need
let mut buf = self.buf.borrow_mut();
let mut reader = self.reader.borrow_mut();
let mut decryptor = self.decryptor.borrow_mut();
let mut buf_ptr = self.buf_ptr.borrow_mut();
let mut bytes_in_buffer = self.bytes_in_buffer.borrow_mut();
let mut bytes_in_reader = self.bytes_in_reader.borrow_mut();
// Assert that our internal buffer is empty
assert_eq!(*buf_ptr, *bytes_in_buffer);
// Clear the buffer and reset size
buf.clear();
buf.resize(BUF_SIZE, 0);
println!("Buffer size: {}", buf.len());
// Read from the reader into the buffer
let new_bytes_read = reader.read(&mut *buf)?;
println!("Read {} bytes", new_bytes_read);
if new_bytes_read >= *bytes_in_reader {
println!("Finalizing decryption");
// let's get the tag.
// there may be some tag bytes in the buffer, but maybe not all of them.
// we need to read the rest of any of them from the reader.
let mut tag_buf = self.tag_buf.borrow_mut();
// get the tag bytes out of the buffer
tag_buf[..new_bytes_read - *bytes_in_reader].copy_from_slice(&buf[*bytes_in_reader..new_bytes_read]);
// zero that part of the buffer
buf[*bytes_in_reader..new_bytes_read].fill(0);
// read the rest of the tag from the reader
reader.read_exact(&mut tag_buf[new_bytes_read - *bytes_in_reader..])?;
// set buf_ptr
*buf_ptr = 0;
// set bytes_in_buffer
*bytes_in_buffer = *bytes_in_reader;
// in this case, the last 16 bytes we read are the tag
*bytes_in_reader = 0;
// set the finalize flag
*self.finalize.borrow_mut() = true;
} else {
// Otherwise, there's more data to decrypt
*bytes_in_reader -= new_bytes_read;
// set buf_ptr
*buf_ptr = 0;
// set bytes_in_buffer
*bytes_in_buffer = new_bytes_read;
}
// if we got anything, decrypt it
if *bytes_in_buffer > 0 {
// // THIS FILE IS DEPRECATED- WE ARE USING AGE INSTEAD
//
//
// use crate::crypto_tools::key_and_nonce_types::{BUF_SIZE, KeyAndNonce, KeyAndNonceToDisk, TAG_SIZE};
// use aead::stream::{Decryptor, NewStream, StreamBE32, StreamPrimitive};
// use aes_gcm::{Aes256Gcm, KeyInit};
// use anyhow::{anyhow, Result};
// use futures::executor;
// use std::cell::RefCell;
// use std::io::{Cursor, ErrorKind, Read, Seek, SeekFrom, Write};
// use std::pin::Pin;
//
// /// A wrapper around a writer that encrypts the data as it is written.
// /// Should not be used on files larger than 32 GB.
// pub struct DecryptionReader<R: Read + Unpin+ Seek> {
// /// Internal buffer, holds data from disk and decrypts it in place
// /// // TODO why a vec? why not a fixed size array?
// buf: RefCell<Vec<u8>>,
// /// tracks how much encrypted data is left in the reader
// bytes_in_reader: RefCell<usize>,
// /// buf_ptr tracks the current position in the buffer- where to start reading decrypted data from
// buf_ptr: RefCell<usize>,
// /// bytes_in_buffer tracks how many bytes are in the buffer- it may not always be full
// bytes_in_buffer: RefCell<usize>,
// /// Writer to another file
// reader: RefCell<R>,
// /// Decryptor. This stores the key
// decryptor: RefCell<Decryptor<Aes256Gcm, StreamBE32<Aes256Gcm>>>,
// /// Counter of bytes read from this struct's read() method
// bytes_read: RefCell<usize>,
// /// buffer to eventually put the tag into
// tag_buf: RefCell<[u8; TAG_SIZE]>,
// /// should we finalize the decryption? this means tag_buf will be filled with the tag and bytes_in_reader will be 0
// finalize: RefCell<bool>,
// }
//
// /// A wrapper around a reader that decrypts the data as it is written.
// impl<R: Read + Unpin + Seek> DecryptionReader<R> {
// /// Create a new DecryptionReader.
// ///
// /// # Arguments
// /// reader: The reader to read encrypted data from. should start with the nonce.
// /// key_and_nonce: The key and nonce to use for decryption.
// ///
// /// # Returns
// /// A DecryptionReader
// pub async fn new(mut reader: R, key_and_nonce: KeyAndNonceToDisk) -> Result<Self> {
// let KeyAndNonce { key, nonce } = *key_and_nonce.consume_and_prep_from_disk()?;
// let cipher = Aes256Gcm::new(&key);
// let decryptor = RefCell::new(StreamBE32::from_aead(cipher, &nonce).decryptor());
//
// let file_len = reader.seek(SeekFrom::End(0))?;
// reader.seek(SeekFrom::Start(0))?;
// Ok(Self {
// buf: RefCell::new(vec![]),
// tag_buf: RefCell::new([0; TAG_SIZE]),
// bytes_in_reader: RefCell::new(file_len as usize - TAG_SIZE),
// bytes_in_buffer: RefCell::new(0),
// buf_ptr: RefCell::new(0),
// reader: reader.into(),
// decryptor,
// bytes_read: RefCell::new(0),
// finalize: RefCell::new(false),
// })
// }
//
// /// Read from the Reader into the buffer, decrypting it in place.
// pub async fn refresh_buffer(&mut self) -> std::io::Result<()> {
// println!("Refreshing buffer");
// // Borrow the mutable references to the fields we need
// let mut buf = self.buf.borrow_mut();
// let mut reader = self.reader.borrow_mut();
// let mut decryptor = self.decryptor.borrow_mut();
// let mut buf_ptr = self.buf_ptr.borrow_mut();
// let mut bytes_in_buffer = self.bytes_in_buffer.borrow_mut();
// let mut bytes_in_reader = self.bytes_in_reader.borrow_mut();
//
// // Assert that our internal buffer is empty
// assert_eq!(*buf_ptr, *bytes_in_buffer);
// // Clear the buffer and reset size
// buf.clear();
// buf.resize(BUF_SIZE, 0);
// println!("Buffer size: {}", buf.len());
// // Read from the reader into the buffer
// let new_bytes_read = reader.read(&mut *buf)?;
// println!("Read {} bytes", new_bytes_read);
//
// if new_bytes_read >= *bytes_in_reader {
// println!("Finalizing decryption");
// // let's get the tag.
// // there may be some tag bytes in the buffer, but maybe not all of them.
// // we need to read the rest of any of them from the reader.
// let mut tag_buf = self.tag_buf.borrow_mut();
// // get the tag bytes out of the buffer
// tag_buf[..new_bytes_read - *bytes_in_reader].copy_from_slice(&buf[*bytes_in_reader..new_bytes_read]);
// // zero that part of the buffer
// buf[*bytes_in_reader..new_bytes_read].fill(0);
// // read the rest of the tag from the reader
// reader.read_exact(&mut tag_buf[new_bytes_read - *bytes_in_reader..])?;
// // set buf_ptr
// *buf_ptr = 0;
// // set bytes_in_buffer
// *bytes_in_buffer = *bytes_in_reader;
// // in this case, the last 16 bytes we read are the tag
// *bytes_in_reader = 0;
// // set the finalize flag
// *self.finalize.borrow_mut() = true;
// } else {
// // Otherwise, there's more data to decrypt
// *bytes_in_reader -= new_bytes_read;
// // set buf_ptr
// *buf_ptr = 0;
// // set bytes_in_buffer
// *bytes_in_buffer = new_bytes_read;
// }
// // if we got anything, decrypt it
// if *bytes_in_buffer > 0 {
// // TODO laudiacay i think this copies
// let mut buf_to_decrypt= buf[..*bytes_in_buffer].to_vec();
// // Decrypt the buffer in place
// (*decryptor)
// .decrypt_next_in_place(b"".as_ref(), &mut buf_to_decrypt)
// .map_err(|_| {
// std::io::Error::new(ErrorKind::Other, anyhow!("Error decrypting block!"))
// })?;
// };
// Ok(())
// }
//
// pub async fn finish(self) -> Result<usize> {
// assert_eq!(self.bytes_in_reader.borrow().clone(), 0);
// assert_eq!(self.finalize.borrow().clone(), true);
// assert_eq!(self.bytes_in_buffer.borrow().clone(), self.buf_ptr.borrow().clone());
// // decrypt_next_in_place
// self.decryptor
// .into_inner()
// .decrypt_next_in_place(b"".as_ref(), self.buf.borrow_mut())
// .map_err(|_| anyhow!("Error decrypting last block"))?;
// // TODO maybe add a sanity check for bytes_read!
// self.decryptor
// .into_inner()
// .decrypt_last_in_place(b"".as_ref(), &mut self.tag_buf.borrow().to_vec())
// .map_err(|_| anyhow!("Error decrypting last block"))?;
// Ok(*self.bytes_read.borrow_mut())
// }
//
// pub fn cipher_info(&self) -> String {
// "AES-256-GCM".to_string()
// }
// }
//
// /// Implement the Read trait for DecryptionReader.
// impl<R: Read + Unpin + Seek> Read for DecryptionReader<R> {
// /// Read from the DecryptionReader into a buffer.
// fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
// // Determine how many bytes can read into the buffer
// let buf_len = buf.len();
// let mut bytes_to_read = buf_len;
// // Declare a cursor to write into the buffer
// let mut buf_cursor = Cursor::new(buf);
// // Create a new pin to borrow the fields we need
// let mut self_pin = Pin::new(&mut *self);
//
// // Read as many bytes as we can into the buffer
// println!("made it");
// while bytes_to_read > 0 && !self_pin.finalize.borrow().clone() {
// println!("made it 2");
// // There's still bytes to read, and we're not at the end of the file
//
// // Determine how many bytes are available in the internal buffer
// let bytes_available = *self_pin.bytes_in_buffer.borrow() - *self_pin.buf_ptr.borrow();
// // If there's more to read than there's space available, read the space available
// println!("bytes available: {}", bytes_available);
// if bytes_available >= bytes_to_read {
// {
// println!("we should not be here");
// let buf_ptr = self_pin.buf_ptr.borrow();
// // Copy the bytes that can be read into the output buffer
// buf_cursor
// .write_all(&self_pin.buf.borrow()[*buf_ptr..*buf_ptr + bytes_to_read])?;
// // Move the buffer pointer to where we left off
// *self_pin.buf_ptr.borrow_mut() += bytes_to_read;
// // We've read all the bytes we can read
// bytes_to_read = 0;
// }
// }
// // Otherwise, read the bytes available
// else {
// println!("we should be here");
// // Do we need to write if bytes_available == 0?
// {
// let mut buf_ptr = self_pin.buf_ptr.borrow_mut();
// // Copy all available bytes from the internal buffer into the output buffer
// buf_cursor
// .write_all(&self_pin.buf.borrow()[*buf_ptr..*buf_ptr + bytes_available])?;
// // Update the buffer pointer (it should now be at the end of the buffer, == bytes_in_buffer)
// *buf_ptr += bytes_available;
// // Update the number of bytes we still need to read
// bytes_to_read -= bytes_available;
// println!("state check: {}", bytes_to_read);
// println!("state check: {}", bytes_available);
// println!("state check: {}", *buf_ptr);
// }
// // Refresh the internal buffer with decrypted data
// // TODO block_on considered harmful
// executor::block_on(self_pin.refresh_buffer())?;
// }
// }
// // Get the buffer back from the cursor
// Ok(buf_len - bytes_to_read)
// }
// }
//
// // TODO (xBalbinus & thea-exe): Our inline tests
// #[cfg(test)]
// mod test {
// use aead::Payload;
// use aead::stream::{NewStream, StreamBE32, StreamPrimitive};
// use aes_gcm::KeyInit;
// use crate::crypto_tools::key_and_nonce_types::KeyAndNonce;
//
// #[tokio::test]
// /// Test that we can decrypt-read some random piece of data with a random key and nonce without
// /// panicking
// async fn test() {
// use super::DecryptionReader;
// use crate::crypto_tools::key_and_nonce_types::{keygen, KeyAndNonceToDisk};
// use aes_gcm::aes::cipher::crypto_common::rand_core::{OsRng, RngCore};
// use std::io::{Cursor, Read};
//
// // generate a random key and nonce
// let keygen @ KeyAndNonce {key, nonce} = keygen();
//
// // generate an all-zero piece of data in a 1kb buffer and wrap it in a cursor
// let mut data = vec![0u8; 1024];
// // encrypt the data
// let mut enc = StreamBE32::from_aead(aes_gcm::Aes256Gcm::new(&key), &nonce).encryptor();
// let encrypted = enc.encrypt_last(Payload::from(&*data)).unwrap();
//
// // Initialize the Decryption Reader
// let mut decryption_reader =
// DecryptionReader::new(Cursor::new(encrypted), keygen.consume_and_prep_to_disk())
// .await
// .unwrap();
//
// // Try and decrypt the data
// let mut decrypted_data = vec![1u8; 1024];
// decryption_reader.read(&mut decrypted_data).unwrap();
// decryption_reader.finish().await.unwrap();
//
// // check that decrypted_data is now all zeros
// assert_eq!(decrypted_data, vec![0u8; 1024]);
// }
// }