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

Merged
lx merged 11 commits from KokaKiwi/garage:aws4-payload-signing into main 2022-01-17 09:55:31 +00:00
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@ -135,6 +135,11 @@ impl<I> From<nom::error::Error<I>> for SignedPayloadStreamError {
} }
} }
struct SignedPayload {
header: payload::Header,
data: Bytes,
}
#[pin_project::pin_project] #[pin_project::pin_project]
pub struct SignedPayloadStream<S> pub struct SignedPayloadStream<S>
where where
@ -160,10 +165,6 @@ where
scope: &str, scope: &str,
seed_signature: Hash, seed_signature: Hash,
) -> Result<Self, Error> { ) -> Result<Self, Error> {
// let signing_hmac =
// super::signing_hmac(&datetime, secret_key, &garage.config.s3_api.s3_region, "s3")
// .ok_or_internal_error("Could not compute signing HMAC")?;
Ok(Self { Ok(Self {
stream, stream,
buf: bytes::BytesMut::new(), buf: bytes::BytesMut::new(),
@ -173,6 +174,36 @@ where
previous_signature: seed_signature, 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> impl<S> Stream for SignedPayloadStream<S>
@ -187,60 +218,42 @@ where
) -> task::Poll<Option<Self::Item>> { ) -> task::Poll<Option<Self::Item>> {
use std::task::Poll; use std::task::Poll;
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Outdated
Review

What if the payload input stream is interrupted in the middle? Do we take care of exiting the infinite loop and return an error?

What if the payload input stream is interrupted in the middle? Do we take care of exiting the infinite loop and return an error?
use nom::bytes::streaming::{tag, take};
let mut this = self.project(); let mut this = self.project();
macro_rules! try_parse { loop {
($eof:expr, $expr:expr) => { let (input, payload) = match Self::parse_next(this.buf) {
match $expr { Ok(res) => res,
Ok(value) => Ok(value),
Err(nom::Err::Incomplete(_)) => { Err(nom::Err::Incomplete(_)) => {
if $eof { 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 => {
if this.buf.is_empty() {
return Poll::Ready(None);
}
KokaKiwi marked this conversation as resolved Outdated

this bit has an invalid edge case : by cutting the stream just before a new chunk header, an attacker can truncate the file without it being rejected. Getting here (inner stream returns None and this.buf is empy) is either such a truncation, or a call to SignedPayloadStream::poll_next after it returned Ok(Ready(None)) once, which is a contract error (Ok(Ready(None)) means that the stream has terminated, and poll_next should not be invoked again), so this check and return can be safely removed

this bit has an invalid edge case : by cutting the stream just before a new chunk header, an attacker can truncate the file without it being rejected. Getting here (inner stream returns None and this.buf is empy) is either such a truncation, or a call to SignedPayloadStream::poll_next after it returned Ok(Ready(None)) once, which is a contract error ([`Ok(Ready(None)) means that the stream has terminated, and poll_next should not be invoked again`](https://docs.rs/futures/0.2.0/futures/stream/trait.Stream.html#return-value)), so this check and return can be safely removed
return Poll::Ready(Some(Err(SignedPayloadStreamError::message( return Poll::Ready(Some(Err(SignedPayloadStreamError::message(
"Unexpected EOF", "Unexpected EOF",
)))); ))));
} }
continue;
} }
Err(nom::Err::Error(e)) | Err(nom::Err::Failure(e)) => Err(e),
}?
};
} }
Err(nom::Err::Error(e)) | Err(nom::Err::Failure(e)) => {
loop { return Poll::Ready(Some(Err(e)))
let eof = match futures::ready!(this.stream.as_mut().poll_next(cx)) {
Some(Ok(bytes)) => {
log::debug!("Received: {:?}", bytes);
this.buf.extend(bytes);
false
}
Some(Err(e)) => return Poll::Ready(Some(Err(SignedPayloadStreamError::Stream(e)))),
None => {
log::debug!("Buf: {:?}", this.buf);
if this.buf.is_empty() {
return Poll::Ready(None);
}
true
} }
}; };
let input: &[u8] = this.buf;
let (input, header) = try_parse!(eof, payload::Header::parse(input));
// 0-sized chunk is the last // 0-sized chunk is the last
if header.size == 0 { if payload.data.is_empty() {
this.buf.clear();
return Poll::Ready(None); return Poll::Ready(None);
} }
let (input, data) = let data_sha256sum = sha256sum(&payload.data);
try_parse!(eof, take::<_, _, nom::error::Error<_>>(header.size)(input));
let (input, _) = try_parse!(eof, tag::<_, _, nom::error::Error<_>>("\r\n")(input));
let data = Bytes::from(data.to_vec());
let data_sha256sum = sha256sum(&data);
let expected_signature = compute_streaming_payload_signature( let expected_signature = compute_streaming_payload_signature(
this.signing_hmac, this.signing_hmac,
@ -253,14 +266,14 @@ where
SignedPayloadStreamError::Message(format!("Could not build signature: {}", e)) SignedPayloadStreamError::Message(format!("Could not build signature: {}", e))
})?; })?;
if header.signature != expected_signature { if payload.header.signature != expected_signature {
return Poll::Ready(Some(Err(SignedPayloadStreamError::InvalidSignature))); return Poll::Ready(Some(Err(SignedPayloadStreamError::InvalidSignature)));
} }
*this.buf = input.into(); *this.buf = input.into();
*this.previous_signature = header.signature; *this.previous_signature = payload.header.signature;
return Poll::Ready(Some(Ok(data))); return Poll::Ready(Some(Ok(payload.data)));
} }
} }