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Grow noise buffers dynamically. #1436

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merged 4 commits into from
Feb 13, 2020
Merged

Grow noise buffers dynamically. #1436

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5b32731
Grow noise buffers dynamically.
twittner Feb 5, 2020
02f724e
Grow write buffer from offset.
twittner Feb 12, 2020
ff3eabc
Merge branch 'master' into noise-dynamic-buffers
twittner Feb 13, 2020
27e6ff9
Merge branch 'master' into noise-dynamic-buffers
tomaka Feb 13, 2020
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2 changes: 1 addition & 1 deletion protocols/noise/Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@ log = "0.4"
prost = "0.6.1"
rand = "0.7.2"
sha2 = "0.8.0"
static_assertions = "1"
x25519-dalek = "0.5"
zeroize = "1"

Expand All @@ -25,7 +26,6 @@ snow = { version = "0.6.1", features = ["ring-resolver"], default-features = fal
[target.'cfg(target_os = "unknown")'.dependencies]
snow = { version = "0.6.1", features = ["default-resolver"], default-features = false }


[dev-dependencies]
env_logger = "0.7.1"
libp2p-tcp = { version = "0.15.0", path = "../../transports/tcp" }
Expand Down
145 changes: 58 additions & 87 deletions protocols/noise/src/io.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -26,33 +26,17 @@ use futures::ready;
use futures::prelude::*;
use log::{debug, trace};
use snow;
use std::{fmt, io, pin::Pin, ops::DerefMut, task::{Context, Poll}};
use std::{cmp::min, fmt, io, pin::Pin, ops::DerefMut, task::{Context, Poll}};

/// Max. size of a noise package.
const MAX_NOISE_PKG_LEN: usize = 65535;
const MAX_WRITE_BUF_LEN: usize = 16384;
const TOTAL_BUFFER_LEN: usize = 2 * MAX_NOISE_PKG_LEN + 3 * MAX_WRITE_BUF_LEN;
/// Extra space given to the encryption buffer to hold key material.
const EXTRA_ENCRYPT_SPACE: usize = 1024;
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That constant looks a bit like dark magic to me, but the test would cover any possible mistake here anyway.

/// Max. output buffer size before forcing a flush.
const MAX_WRITE_BUF_LEN: usize = MAX_NOISE_PKG_LEN - EXTRA_ENCRYPT_SPACE;

/// A single `Buffer` contains multiple non-overlapping byte buffers.
struct Buffer {
inner: Box<[u8; TOTAL_BUFFER_LEN]>
}

/// A mutable borrow of all byte buffers, backed by `Buffer`.
struct BufferBorrow<'a> {
read: &'a mut [u8],
read_crypto: &'a mut [u8],
write: &'a mut [u8],
write_crypto: &'a mut [u8]
}

impl Buffer {
/// Create a mutable borrow by splitting the buffer slice.
fn borrow_mut(&mut self) -> BufferBorrow<'_> {
let (r, w) = self.inner.split_at_mut(2 * MAX_NOISE_PKG_LEN);
let (read, read_crypto) = r.split_at_mut(MAX_NOISE_PKG_LEN);
let (write, write_crypto) = w.split_at_mut(MAX_WRITE_BUF_LEN);
BufferBorrow { read, read_crypto, write, write_crypto }
}
static_assertions::const_assert! {
MAX_WRITE_BUF_LEN + EXTRA_ENCRYPT_SPACE <= MAX_NOISE_PKG_LEN
}

/// A passthrough enum for the two kinds of state machines in `snow`
Expand Down Expand Up @@ -97,9 +81,12 @@ impl SnowState {
pub struct NoiseOutput<T> {
io: T,
session: SnowState,
buffer: Buffer,
read_state: ReadState,
write_state: WriteState
write_state: WriteState,
read_buffer: Vec<u8>,
write_buffer: Vec<u8>,
decrypt_buffer: Vec<u8>,
encrypt_buffer: Vec<u8>
}

impl<T> fmt::Debug for NoiseOutput<T> {
Expand All @@ -116,9 +103,12 @@ impl<T> NoiseOutput<T> {
NoiseOutput {
io,
session,
buffer: Buffer { inner: Box::new([0; TOTAL_BUFFER_LEN]) },
read_state: ReadState::Init,
write_state: WriteState::Init
write_state: WriteState::Init,
read_buffer: Vec::new(),
write_buffer: Vec::new(),
decrypt_buffer: Vec::new(),
encrypt_buffer: Vec::new()
}
}
}
Expand Down Expand Up @@ -159,15 +149,8 @@ enum WriteState {
}

impl<T: AsyncRead + Unpin> AsyncRead for NoiseOutput<T> {
fn poll_read(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8],
) -> Poll<Result<usize, std::io::Error>> {
fn poll_read(mut self: Pin<&mut Self>, cx: &mut Context, buf: &mut [u8]) -> Poll<io::Result<usize>> {
let mut this = self.deref_mut();

let buffer = this.buffer.borrow_mut();

loop {
trace!("read state: {:?}", this.read_state);
match this.read_state {
Expand All @@ -187,7 +170,6 @@ impl<T: AsyncRead + Unpin> AsyncRead for NoiseOutput<T> {
}
Poll::Pending => {
this.read_state = ReadState::ReadLen { buf, off };

return Poll::Pending;
}
};
Expand All @@ -197,30 +179,28 @@ impl<T: AsyncRead + Unpin> AsyncRead for NoiseOutput<T> {
this.read_state = ReadState::Init;
continue
}
this.read_buffer.resize(usize::from(n), 0u8);
this.read_state = ReadState::ReadData { len: usize::from(n), off: 0 }
}
ReadState::ReadData { len, ref mut off } => {
let n = match ready!(
Pin::new(&mut this.io).poll_read(cx, &mut buffer.read[*off ..len])
) {
Ok(n) => n,
Err(e) => return Poll::Ready(Err(e)),
let n = {
let f = Pin::new(&mut this.io).poll_read(cx, &mut this.read_buffer[*off .. len]);
match ready!(f) {
Ok(n) => n,
Err(e) => return Poll::Ready(Err(e)),
}
};

trace!("read: read {}/{} bytes", *off + n, len);
if n == 0 {
trace!("read: eof");
this.read_state = ReadState::Eof(Err(()));
return Poll::Ready(Err(io::ErrorKind::UnexpectedEof.into()))
}

*off += n;
if len == *off {
trace!("read: decrypting {} bytes", len);
if let Ok(n) = this.session.read_message(
&buffer.read[.. len],
buffer.read_crypto
){
this.decrypt_buffer.resize(len, 0u8);
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At this point len is the size of the encrypted message in this.read_buffer, correct? Do you resize this.decrypt_buffer to len to ensure it is large enough, given that the decrypted payload will always be smaller than the encrypted payload?

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Yes.

if let Ok(n) = this.session.read_message(&this.read_buffer, &mut this.decrypt_buffer) {
trace!("read: payload len = {} bytes", n);
this.read_state = ReadState::CopyData { len: n, off: 0 }
} else {
Expand All @@ -231,8 +211,8 @@ impl<T: AsyncRead + Unpin> AsyncRead for NoiseOutput<T> {
}
}
ReadState::CopyData { len, ref mut off } => {
let n = std::cmp::min(len - *off, buf.len());
buf[.. n].copy_from_slice(&buffer.read_crypto[*off .. *off + n]);
let n = min(len - *off, buf.len());
buf[.. n].copy_from_slice(&this.decrypt_buffer[*off .. *off + n]);
trace!("read: copied {}/{} bytes", *off + n, len);
*off += n;
if len == *off {
Expand All @@ -255,29 +235,25 @@ impl<T: AsyncRead + Unpin> AsyncRead for NoiseOutput<T> {
}

impl<T: AsyncWrite + Unpin> AsyncWrite for NoiseOutput<T> {
fn poll_write(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<Result<usize, std::io::Error>>{
fn poll_write(mut self: Pin<&mut Self>, cx: &mut Context, buf: &[u8]) -> Poll<io::Result<usize>> {
let mut this = self.deref_mut();

let buffer = this.buffer.borrow_mut();

loop {
trace!("write state: {:?}", this.write_state);
match this.write_state {
WriteState::Init => {
this.write_state = WriteState::BufferData { off: 0 }
}
WriteState::BufferData { ref mut off } => {
let n = std::cmp::min(MAX_WRITE_BUF_LEN - *off, buf.len());
buffer.write[*off .. *off + n].copy_from_slice(&buf[.. n]);
let n = min(MAX_WRITE_BUF_LEN, off.saturating_add(buf.len()));
this.write_buffer.resize(n, 0u8);
let n = min(MAX_WRITE_BUF_LEN - *off, buf.len());
this.write_buffer[*off .. *off + n].copy_from_slice(&buf[.. n]);
trace!("write: buffered {} bytes", *off + n);
*off += n;
if *off == MAX_WRITE_BUF_LEN {
trace!("write: encrypting {} bytes", *off);
match this.session.write_message(buffer.write, buffer.write_crypto) {
this.encrypt_buffer.resize(MAX_WRITE_BUF_LEN + EXTRA_ENCRYPT_SPACE, 0u8);
match this.session.write_message(&this.write_buffer, &mut this.encrypt_buffer) {
Ok(n) => {
trace!("write: cipher text len = {} bytes", n);
this.write_state = WriteState::WriteLen {
Expand Down Expand Up @@ -316,11 +292,12 @@ impl<T: AsyncWrite + Unpin> AsyncWrite for NoiseOutput<T> {
this.write_state = WriteState::WriteData { len, off: 0 }
}
WriteState::WriteData { len, ref mut off } => {
let n = match ready!(
Pin::new(&mut this.io).poll_write(cx, &buffer.write_crypto[*off .. len])
) {
Ok(n) => n,
Err(e) => return Poll::Ready(Err(e)),
let n = {
let f = Pin::new(&mut this.io).poll_write(cx, &this.encrypt_buffer[*off .. len]);
match ready!(f) {
Ok(n) => n,
Err(e) => return Poll::Ready(Err(e))
}
};
trace!("write: wrote {}/{} bytes", *off + n, len);
if n == 0 {
Expand All @@ -343,20 +320,17 @@ impl<T: AsyncWrite + Unpin> AsyncWrite for NoiseOutput<T> {
}
}

fn poll_flush(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>
) -> Poll<Result<(), std::io::Error>> {
fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<io::Result<()>> {
let mut this = self.deref_mut();

let buffer = this.buffer.borrow_mut();

loop {
match this.write_state {
WriteState::Init => return Pin::new(&mut this.io).poll_flush(cx),
WriteState::Init => {
return Pin::new(&mut this.io).poll_flush(cx)
}
WriteState::BufferData { off } => {
trace!("flush: encrypting {} bytes", off);
match this.session.write_message(&buffer.write[.. off], buffer.write_crypto) {
this.encrypt_buffer.resize(off + EXTRA_ENCRYPT_SPACE, 0u8);
match this.session.write_message(&this.write_buffer[.. off], &mut this.encrypt_buffer) {
Ok(n) => {
trace!("flush: cipher text len = {} bytes", n);
this.write_state = WriteState::WriteLen {
Expand Down Expand Up @@ -386,18 +360,18 @@ impl<T: AsyncWrite + Unpin> AsyncWrite for NoiseOutput<T> {
}
Poll::Pending => {
this.write_state = WriteState::WriteLen { len, buf, off };

return Poll::Pending
}
}
this.write_state = WriteState::WriteData { len, off: 0 }
}
WriteState::WriteData { len, ref mut off } => {
let n = match ready!(
Pin::new(&mut this.io).poll_write(cx, &buffer.write_crypto[*off .. len])
) {
Ok(n) => n,
Err(e) => return Poll::Ready(Err(e)),
let n = {
let f = Pin::new(&mut this.io).poll_write(cx, &this.encrypt_buffer[*off .. len]);
match ready!(f) {
Ok(n) => n,
Err(e) => return Poll::Ready(Err(e)),
}
};
trace!("flush: wrote {}/{} bytes", *off + n, len);
if n == 0 {
Expand All @@ -420,10 +394,7 @@ impl<T: AsyncWrite + Unpin> AsyncWrite for NoiseOutput<T> {
}
}

fn poll_close(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Result<(), std::io::Error>>{
fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<io::Result<()>>{
ready!(self.as_mut().poll_flush(cx))?;
Pin::new(&mut self.io).poll_close(cx)
}
Expand All @@ -443,7 +414,7 @@ fn read_frame_len<R: AsyncRead + Unpin>(
cx: &mut Context<'_>,
buf: &mut [u8; 2],
off: &mut usize,
) -> Poll<Result<Option<u16>, std::io::Error>> {
) -> Poll<io::Result<Option<u16>>> {
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Commenting on this PR as well, because I comment every time someone does that: I'm not a fan of doing random codestyle changes, especially for code that isn't otherwise touched by the PR.

loop {
match ready!(Pin::new(&mut io).poll_read(cx, &mut buf[*off ..])) {
Ok(n) => {
Expand Down Expand Up @@ -476,7 +447,7 @@ fn write_frame_len<W: AsyncWrite + Unpin>(
cx: &mut Context<'_>,
buf: &[u8; 2],
off: &mut usize,
) -> Poll<Result<bool, std::io::Error>> {
) -> Poll<io::Result<bool>> {
loop {
match ready!(Pin::new(&mut io).poll_write(cx, &buf[*off ..])) {
Ok(n) => {
Expand Down
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