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>
author: Jill <kokakiwi@deuxfleurs.fr> 2022-01-17 10:55:31 +0100
committer: Alex <alex@adnab.me> 2022-01-17 10:55:31 +0100
commit: b45dcc1925d76f3f7dcae7deea0391953ba548e5 (patch)
tree: 85600f90c41532dc0b50e395e6ea85ca8ba08f53 /src/api/signature
parent: 60c0033c8bbd3dbc18f8c91f15674a60fd8acdc0 (diff)
download: garage-b45dcc1925d76f3f7dcae7deea0391953ba548e5.tar.gz
garage-b45dcc1925d76f3f7dcae7deea0391953ba548e5.zip
3 files changed, 635 insertions, 0 deletions
diff --git a/src/api/signature/mod.rs b/src/api/signature/mod.rs
new file mode 100644
index 00000000..ebdee6da
--- /dev/null
+++ b/src/api/signature/mod.rs
@@ -0,0 +1,47 @@
+use chrono::{DateTime, Utc};
+use hmac::{Hmac, Mac, NewMac};
+use sha2::Sha256;
+
+use garage_util::data::{sha256sum, Hash};
+
+use crate::error::*;
+
+pub mod payload;
+pub mod streaming;
+
+pub const SHORT_DATE: &str = "%Y%m%d";
+pub const LONG_DATETIME: &str = "%Y%m%dT%H%M%SZ";
+
+type HmacSha256 = Hmac<Sha256>;
+
+pub fn verify_signed_content(expected_sha256: Hash, body: &[u8]) -> Result<(), Error> {
+	if expected_sha256 != sha256sum(body) {
+		return Err(Error::BadRequest(
+			"Request content hash does not match signed hash".to_string(),
+		));
+	}
+	Ok(())
+}
+
+pub fn signing_hmac(
+	datetime: &DateTime<Utc>,
+	secret_key: &str,
+	region: &str,
+	service: &str,
+) -> Result<HmacSha256, crypto_mac::InvalidKeyLength> {
+	let secret = String::from("AWS4") + secret_key;
+	let mut date_hmac = HmacSha256::new_varkey(secret.as_bytes())?;
+	date_hmac.update(datetime.format(SHORT_DATE).to_string().as_bytes());
+	let mut region_hmac = HmacSha256::new_varkey(&date_hmac.finalize().into_bytes())?;
+	region_hmac.update(region.as_bytes());
+	let mut service_hmac = HmacSha256::new_varkey(&region_hmac.finalize().into_bytes())?;
+	service_hmac.update(service.as_bytes());
+	let mut signing_hmac = HmacSha256::new_varkey(&service_hmac.finalize().into_bytes())?;
+	signing_hmac.update(b"aws4_request");
+	let hmac = HmacSha256::new_varkey(&signing_hmac.finalize().into_bytes())?;
+	Ok(hmac)
+}
+
+pub fn compute_scope(datetime: &DateTime<Utc>, region: &str) -> String {
+	format!("{}/{}/s3/aws4_request", datetime.format(SHORT_DATE), region,)
+}
diff --git a/src/api/signature/payload.rs b/src/api/signature/payload.rs
new file mode 100644
index 00000000..b13819a8
--- /dev/null
+++ b/src/api/signature/payload.rs
@@ -0,0 +1,269 @@
+use std::collections::HashMap;
+
+use chrono::{DateTime, Duration, NaiveDateTime, Utc};
+use hmac::Mac;
+use hyper::{Body, Method, Request};
+use sha2::{Digest, Sha256};
+
+use garage_table::*;
+use garage_util::data::Hash;
+
+use garage_model::garage::Garage;
+use garage_model::key_table::*;
+
+use super::signing_hmac;
+use super::{LONG_DATETIME, SHORT_DATE};
+
+use crate::encoding::uri_encode;
+use crate::error::*;
+
+pub async fn check_payload_signature(
+	garage: &Garage,
+	request: &Request<Body>,
+) -> Result<(Key, Option<Hash>), Error> {
+	let mut headers = HashMap::new();
+	for (key, val) in request.headers() {
+		headers.insert(key.to_string(), val.to_str()?.to_string());
+	}
+	if let Some(query) = request.uri().query() {
+		let query_pairs = url::form_urlencoded::parse(query.as_bytes());
+		for (key, val) in query_pairs {
+			headers.insert(key.to_lowercase(), val.to_string());
+		}
+	}
+
+	let authorization = if let Some(authorization) = headers.get("authorization") {
+		parse_authorization(authorization, &headers)?
+	} else {
+		parse_query_authorization(&headers)?
+	};
+
+	let date = headers
+		.get("x-amz-date")
+		.ok_or_bad_request("Missing X-Amz-Date field")?;
+	let date: NaiveDateTime =
+		NaiveDateTime::parse_from_str(date, LONG_DATETIME).ok_or_bad_request("Invalid date")?;
+	let date: DateTime<Utc> = DateTime::from_utc(date, Utc);
+
+	if Utc::now() - date > Duration::hours(24) {
+		return Err(Error::BadRequest("Date is too old".to_string()));
+	}
+
+	let scope = format!(
+		"{}/{}/s3/aws4_request",
+		date.format(SHORT_DATE),
+		garage.config.s3_api.s3_region
+	);
+	if authorization.scope != scope {
+		return Err(Error::AuthorizationHeaderMalformed(scope.to_string()));
+	}
+
+	let key = garage
+		.key_table
+		.get(&EmptyKey, &authorization.key_id)
+		.await?
+		.filter(|k| !k.state.is_deleted())
+		.ok_or_else(|| Error::Forbidden(format!("No such key: {}", authorization.key_id)))?;
+	let key_p = key.params().unwrap();
+
+	let canonical_request = canonical_request(
+		request.method(),
+		&request.uri().path().to_string(),
+		&canonical_query_string(request.uri()),
+		&headers,
+		&authorization.signed_headers,
+		&authorization.content_sha256,
+	);
+	let string_to_sign = string_to_sign(&date, &scope, &canonical_request);
+
+	let mut hmac = signing_hmac(
+		&date,
+		&key_p.secret_key,
+		&garage.config.s3_api.s3_region,
+		"s3",
+	)
+	.ok_or_internal_error("Unable to build signing HMAC")?;
+	hmac.update(string_to_sign.as_bytes());
+	let signature = hex::encode(hmac.finalize().into_bytes());
+
+	if authorization.signature != signature {
+		trace!("Canonical request: ``{}``", canonical_request);
+		trace!("String to sign: ``{}``", string_to_sign);
+		trace!("Expected: {}, got: {}", signature, authorization.signature);
+		return Err(Error::Forbidden("Invalid signature".to_string()));
+	}
+
+	let content_sha256 = if authorization.content_sha256 == "UNSIGNED-PAYLOAD" {
+		None
+	} else if authorization.content_sha256 == "STREAMING-AWS4-HMAC-SHA256-PAYLOAD" {
+		let bytes = hex::decode(authorization.signature).ok_or_bad_request("Invalid signature")?;
+		Some(Hash::try_from(&bytes).ok_or_bad_request("Invalid signature")?)
+	} else {
+		let bytes = hex::decode(authorization.content_sha256)
+			.ok_or_bad_request("Invalid content sha256 hash")?;
+		Some(Hash::try_from(&bytes).ok_or_bad_request("Invalid content sha256 hash")?)
+	};
+
+	Ok((key, content_sha256))
+}
+
+struct Authorization {
+	key_id: String,
+	scope: String,
+	signed_headers: String,
+	signature: String,
+	content_sha256: String,
+}
+
+fn parse_authorization(
+	authorization: &str,
+	headers: &HashMap<String, String>,
+) -> Result<Authorization, Error> {
+	let first_space = authorization
+		.find(' ')
+		.ok_or_bad_request("Authorization field to short")?;
+	let (auth_kind, rest) = authorization.split_at(first_space);
+
+	if auth_kind != "AWS4-HMAC-SHA256" {
+		return Err(Error::BadRequest("Unsupported authorization method".into()));
+	}
+
+	let mut auth_params = HashMap::new();
+	for auth_part in rest.split(',') {
+		let auth_part = auth_part.trim();
+		let eq = auth_part
+			.find('=')
+			.ok_or_bad_request("Field without value in authorization header")?;
+		let (key, value) = auth_part.split_at(eq);
+		auth_params.insert(key.to_string(), value.trim_start_matches('=').to_string());
+	}
+
+	let cred = auth_params
+		.get("Credential")
+		.ok_or_bad_request("Could not find Credential in Authorization field")?;
+	let (key_id, scope) = parse_credential(cred)?;
+
+	let content_sha256 = headers
+		.get("x-amz-content-sha256")
+		.ok_or_bad_request("Missing X-Amz-Content-Sha256 field")?;
+
+	let auth = Authorization {
+		key_id,
+		scope,
+		signed_headers: auth_params
+			.get("SignedHeaders")
+			.ok_or_bad_request("Could not find SignedHeaders in Authorization field")?
+			.to_string(),
+		signature: auth_params
+			.get("Signature")
+			.ok_or_bad_request("Could not find Signature in Authorization field")?
+			.to_string(),
+		content_sha256: content_sha256.to_string(),
+	};
+	Ok(auth)
+}
+
+fn parse_query_authorization(headers: &HashMap<String, String>) -> Result<Authorization, Error> {
+	let algo = headers
+		.get("x-amz-algorithm")
+		.ok_or_bad_request("X-Amz-Algorithm not found in query parameters")?;
+	if algo != "AWS4-HMAC-SHA256" {
+		return Err(Error::BadRequest(
+			"Unsupported authorization method".to_string(),
+		));
+	}
+
+	let cred = headers
+		.get("x-amz-credential")
+		.ok_or_bad_request("X-Amz-Credential not found in query parameters")?;
+	let (key_id, scope) = parse_credential(cred)?;
+	let signed_headers = headers
+		.get("x-amz-signedheaders")
+		.ok_or_bad_request("X-Amz-SignedHeaders not found in query parameters")?;
+	let signature = headers
+		.get("x-amz-signature")
+		.ok_or_bad_request("X-Amz-Signature not found in query parameters")?;
+	let content_sha256 = headers
+		.get("x-amz-content-sha256")
+		.map(|x| x.as_str())
+		.unwrap_or("UNSIGNED-PAYLOAD");
+
+	Ok(Authorization {
+		key_id,
+		scope,
+		signed_headers: signed_headers.to_string(),
+		signature: signature.to_string(),
+		content_sha256: content_sha256.to_string(),
+	})
+}
+
+fn parse_credential(cred: &str) -> Result<(String, String), Error> {
+	let first_slash = cred
+		.find('/')
+		.ok_or_bad_request("Credentials does not contain / in authorization field")?;
+	let (key_id, scope) = cred.split_at(first_slash);
+	Ok((
+		key_id.to_string(),
+		scope.trim_start_matches('/').to_string(),
+	))
+}
+
+fn string_to_sign(datetime: &DateTime<Utc>, scope_string: &str, canonical_req: &str) -> String {
+	let mut hasher = Sha256::default();
+	hasher.update(canonical_req.as_bytes());
+	[
+		"AWS4-HMAC-SHA256",
+		&datetime.format(LONG_DATETIME).to_string(),
+		scope_string,
+		&hex::encode(hasher.finalize().as_slice()),
+	]
+	.join("\n")
+}
+
+fn canonical_request(
+	method: &Method,
+	url_path: &str,
+	canonical_query_string: &str,
+	headers: &HashMap<String, String>,
+	signed_headers: &str,
+	content_sha256: &str,
+) -> String {
+	[
+		method.as_str(),
+		url_path,
+		canonical_query_string,
+		&canonical_header_string(headers, signed_headers),
+		"",
+		signed_headers,
+		content_sha256,
+	]
+	.join("\n")
+}
+
+fn canonical_header_string(headers: &HashMap<String, String>, signed_headers: &str) -> String {
+	let signed_headers_vec = signed_headers.split(';').collect::<Vec<_>>();
+	let mut items = headers
+		.iter()
+		.filter(|(key, _)| signed_headers_vec.contains(&key.as_str()))
+		.collect::<Vec<_>>();
+	items.sort_by(|(k1, _), (k2, _)| k1.cmp(k2));
+	items
+		.iter()
+		.map(|(key, value)| key.to_lowercase() + ":" + value.trim())
+		.collect::<Vec<_>>()
+		.join("\n")
+}
+
+fn canonical_query_string(uri: &hyper::Uri) -> String {
+	if let Some(query) = uri.query() {
+		let query_pairs = url::form_urlencoded::parse(query.as_bytes());
+		let mut items = query_pairs
+			.filter(|(key, _)| key != "X-Amz-Signature")
+			.map(|(key, value)| uri_encode(&key, true) + "=" + &uri_encode(&value, true))
+			.collect::<Vec<_>>();
+		items.sort();
+		items.join("&")
+	} else {
+		"".to_string()
+	}
+}
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
+			),
+		}
+	}
+}
author	Jill <kokakiwi@deuxfleurs.fr>	2022-01-17 10:55:31 +0100
committer	Alex <alex@adnab.me>	2022-01-17 10:55:31 +0100
commit	b45dcc1925d76f3f7dcae7deea0391953ba548e5 (patch)
tree	85600f90c41532dc0b50e395e6ea85ca8ba08f53 /src/api/signature
parent	60c0033c8bbd3dbc18f8c91f15674a60fd8acdc0 (diff)
download	garage-b45dcc1925d76f3f7dcae7deea0391953ba548e5.tar.gz garage-b45dcc1925d76f3f7dcae7deea0391953ba548e5.zip