aboutsummaryrefslogtreecommitdiff
path: root/src/api/signature/streaming.rs
blob: c8358c4fe232617250b5e1d63eb9e682dd0df2b7 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
use std::pin::Pin;

use chrono::{DateTime, NaiveDateTime, Utc};
use futures::prelude::*;
use futures::task;
use garage_model::key_table::Key;
use hmac::Mac;
use hyper::body::Bytes;
use hyper::{Body, Request};

use garage_util::data::Hash;

use super::{compute_scope, sha256sum, HmacSha256, LONG_DATETIME};

use crate::signature::error::*;

pub fn parse_streaming_body(
	api_key: &Key,
	req: Request<Body>,
	content_sha256: &mut Option<Hash>,
	region: &str,
	service: &str,
) -> Result<Request<Body>, Error> {
	match req.headers().get("x-amz-content-sha256") {
		Some(header) if header == "STREAMING-AWS4-HMAC-SHA256-PAYLOAD" => {
			let signature = content_sha256
				.take()
				.ok_or_bad_request("No signature provided")?;

			let secret_key = &api_key
				.state
				.as_option()
				.ok_or_internal_error("Deleted key state")?
				.secret_key;

			let date = req
				.headers()
				.get("x-amz-date")
				.ok_or_bad_request("Missing X-Amz-Date field")?
				.to_str()?;
			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);

			let scope = compute_scope(&date, region, service);
			let signing_hmac = crate::signature::signing_hmac(&date, secret_key, region, service)
				.ok_or_internal_error("Unable to build signing HMAC")?;

			Ok(req.map(move |body| {
				Body::wrap_stream(
					SignedPayloadStream::new(
						body.map_err(Error::from),
						signing_hmac,
						date,
						&scope,
						signature,
					)
					.map_err(Error::from),
				)
			}))
		}
		_ => Ok(req),
	}
}

/// 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());

	Ok(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::bad_request("Invalid payload signature")
			}
			SignedPayloadStreamError::Message(e) => {
				Error::bad_request(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, "s3");
		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);

		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
			),
		}
	}
}