Support STREAMING-AWS4-HMAC-SHA256-PAYLOAD (#64) (#156)

Closes #64.

Reviewed-on: https://git.deuxfleurs.fr/Deuxfleurs/garage/pulls/156
Co-authored-by: Jill <kokakiwi@deuxfleurs.fr>
Co-committed-by: Jill <kokakiwi@deuxfleurs.fr>

1 files changed, 319 insertions, 0 deletions

diff --git a/src/api/signature/streaming.rs b/src/api/signature/streaming.rs
new file mode 100644
index 00000000..b2dc1591
--- /dev/null
+++ b/src/api/signature/streaming.rs
@@ -0,0 +1,319 @@
+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,
+	) -> Result<Self, Error> {
+		Ok(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
+			),
+		}
+	}
+}