use std::pin::Pin;
use chrono::{DateTime, Utc};
use futures::prelude::*;
use futures::task;
use hyper::body::Bytes;
use garage_util::data::Hash;
use hmac::Mac;
use super::sha256sum;
use super::HmacSha256;
use super::LONG_DATETIME;
use crate::error::*;
/// Result of `sha256("")`
const EMPTY_STRING_HEX_DIGEST: &str =
"e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855";
fn compute_streaming_payload_signature(
signing_hmac: &HmacSha256,
date: DateTime<Utc>,
scope: &str,
previous_signature: Hash,
content_sha256: Hash,
) -> Result<Hash, Error> {
let string_to_sign = [
"AWS4-HMAC-SHA256-PAYLOAD",
&date.format(LONG_DATETIME).to_string(),
scope,
&hex::encode(previous_signature),
EMPTY_STRING_HEX_DIGEST,
&hex::encode(content_sha256),
]
.join("\n");
let mut hmac = signing_hmac.clone();
hmac.update(string_to_sign.as_bytes());
Hash::try_from(&hmac.finalize().into_bytes()).ok_or_internal_error("Invalid signature")
}
mod payload {
use garage_util::data::Hash;
pub enum Error<I> {
Parser(nom::error::Error<I>),
BadSignature,
}
impl<I> Error<I> {
pub fn description(&self) -> &str {
match *self {
Error::Parser(ref e) => e.code.description(),
Error::BadSignature => "Bad signature",
}
}
}
#[derive(Debug, Clone)]
pub struct Header {
pub size: usize,
pub signature: Hash,
}
impl Header {
pub fn parse(input: &[u8]) -> nom::IResult<&[u8], Self, Error<&[u8]>> {
use nom::bytes::streaming::tag;
use nom::character::streaming::hex_digit1;
use nom::combinator::map_res;
use nom::number::streaming::hex_u32;
macro_rules! try_parse {
($expr:expr) => {
$expr.map_err(|e| e.map(Error::Parser))?
};
}
let (input, size) = try_parse!(hex_u32(input));
let (input, _) = try_parse!(tag(";")(input));
let (input, _) = try_parse!(tag("chunk-signature=")(input));
let (input, data) = try_parse!(map_res(hex_digit1, hex::decode)(input));
let signature = Hash::try_from(&data).ok_or(nom::Err::Failure(Error::BadSignature))?;
let (input, _) = try_parse!(tag("\r\n")(input));
let header = Header {
size: size as usize,
signature,
};
Ok((input, header))
}
}
}
#[derive(Debug)]
pub enum SignedPayloadStreamError {
Stream(Error),
InvalidSignature,
Message(String),
}
impl SignedPayloadStreamError {
fn message(msg: &str) -> Self {
SignedPayloadStreamError::Message(msg.into())
}
}
impl From<SignedPayloadStreamError> for Error {
fn from(err: SignedPayloadStreamError) -> Self {
match err {
SignedPayloadStreamError::Stream(e) => e,
SignedPayloadStreamError::InvalidSignature => {
Error::BadRequest("Invalid payload signature".into())
}
SignedPayloadStreamError::Message(e) => {
Error::BadRequest(format!("Chunk format error: {}", e))
}
}
}
}
impl<I> From<payload::Error<I>> for SignedPayloadStreamError {
fn from(err: payload::Error<I>) -> Self {
Self::message(err.description())
}
}
impl<I> From<nom::error::Error<I>> for SignedPayloadStreamError {
fn from(err: nom::error::Error<I>) -> Self {
Self::message(err.code.description())
}
}
struct SignedPayload {
header: payload::Header,
data: Bytes,
}
#[pin_project::pin_project]
pub struct SignedPayloadStream<S>
where
S: Stream<Item = Result<Bytes, Error>>,
{
#[pin]
stream: S,
buf: bytes::BytesMut,
datetime: DateTime<Utc>,
scope: String,
signing_hmac: HmacSha256,
previous_signature: Hash,
}
impl<S> SignedPayloadStream<S>
where
S: Stream<Item = Result<Bytes, Error>>,
{
pub fn new(
stream: S,
signing_hmac: HmacSha256,
datetime: DateTime<Utc>,
scope: &str,
seed_signature: Hash,
) -> Self {
Self {
stream,
buf: bytes::BytesMut::new(),
datetime,
scope: scope.into(),
signing_hmac,
previous_signature: seed_signature,
}
}
fn parse_next(input: &[u8]) -> nom::IResult<&[u8], SignedPayload, SignedPayloadStreamError> {
use nom::bytes::streaming::{tag, take};
macro_rules! try_parse {
($expr:expr) => {
$expr.map_err(nom::Err::convert)?
};
}
let (input, header) = try_parse!(payload::Header::parse(input));
// 0-sized chunk is the last
if header.size == 0 {
return Ok((
input,
SignedPayload {
header,
data: Bytes::new(),
},
));
}
let (input, data) = try_parse!(take::<_, _, nom::error::Error<_>>(header.size)(input));
let (input, _) = try_parse!(tag::<_, _, nom::error::Error<_>>("\r\n")(input));
let data = Bytes::from(data.to_vec());
Ok((input, SignedPayload { header, data }))
}
}
impl<S> Stream for SignedPayloadStream<S>
where
S: Stream<Item = Result<Bytes, Error>> + Unpin,
{
type Item = Result<Bytes, SignedPayloadStreamError>;
fn poll_next(
self: Pin<&mut Self>,
cx: &mut task::Context<'_>,
) -> task::Poll<Option<Self::Item>> {
use std::task::Poll;
let mut this = self.project();
loop {
let (input, payload) = match Self::parse_next(this.buf) {
Ok(res) => res,
Err(nom::Err::Incomplete(_)) => {
match futures::ready!(this.stream.as_mut().poll_next(cx)) {
Some(Ok(bytes)) => {
this.buf.extend(bytes);
continue;
}
Some(Err(e)) => {
return Poll::Ready(Some(Err(SignedPayloadStreamError::Stream(e))))
}
None => {
return Poll::Ready(Some(Err(SignedPayloadStreamError::message(
"Unexpected EOF",
))));
}
}
}
Err(nom::Err::Error(e)) | Err(nom::Err::Failure(e)) => {
return Poll::Ready(Some(Err(e)))
}
};
// 0-sized chunk is the last
if payload.data.is_empty() {
return Poll::Ready(None);
}
let data_sha256sum = sha256sum(&payload.data);
let expected_signature = compute_streaming_payload_signature(
this.signing_hmac,
*this.datetime,
this.scope,
*this.previous_signature,
data_sha256sum,
)
.map_err(|e| {
SignedPayloadStreamError::Message(format!("Could not build signature: {}", e))
})?;
if payload.header.signature != expected_signature {
return Poll::Ready(Some(Err(SignedPayloadStreamError::InvalidSignature)));
}
*this.buf = input.into();
*this.previous_signature = payload.header.signature;
return Poll::Ready(Some(Ok(payload.data)));
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
self.stream.size_hint()
}
}
#[cfg(test)]
mod tests {
use futures::prelude::*;
use super::{SignedPayloadStream, SignedPayloadStreamError};
#[tokio::test]
async fn test_interrupted_signed_payload_stream() {
use chrono::{DateTime, Utc};
use garage_util::data::Hash;
let datetime = DateTime::parse_from_rfc3339("2021-12-13T13:12:42+01:00") // TODO UNIX 0
.unwrap()
.with_timezone(&Utc);
let secret_key = "test";
let region = "test";
let scope = crate::signature::compute_scope(&datetime, region);
let signing_hmac =
crate::signature::signing_hmac(&datetime, secret_key, region, "s3").unwrap();
let data: &[&[u8]] = &[b"1"];
let body = futures::stream::iter(data.iter().map(|block| Ok(block.as_ref().into())));
let seed_signature = Hash::default();
let mut stream =
SignedPayloadStream::new(body, signing_hmac, datetime, &scope, seed_signature).unwrap();
assert!(stream.try_next().await.is_err());
match stream.try_next().await {
Err(SignedPayloadStreamError::Message(msg)) if msg == "Unexpected EOF" => {}
item => panic!(
"Unexpected result, expected early EOF error, got {:?}",
item
),
}
}
}
