feat(tvix/store/pathinfosvc/nix_http): check Nar{Size,Hash} matches

Ensure the initially communicated NarHash/NarSize from the NarInfo
matches what we read, and don't return a PathInfo message if there's
a mismatch.

Also move the buffering layer around a bit.

Change-Id: I68c60ecfaf0f9cd5edacea648437ecb0c9729251
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10148
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This commit is contained in:
Florian Klink 2023-11-27 19:43:27 +02:00 committed by flokli
parent fce9c0e99e
commit 7e8719be91

View file

@ -1,5 +1,5 @@
use std::{
io::{self, BufRead},
io::{self, BufRead, Read, Write},
pin::Pin,
sync::Arc,
};
@ -8,6 +8,7 @@ use data_encoding::BASE64;
use futures::{Stream, TryStreamExt};
use nix_compat::{narinfo::NarInfo, nixbase32};
use reqwest::StatusCode;
use sha2::{digest::FixedOutput, Digest, Sha256};
use tonic::async_trait;
use tracing::{debug, instrument, warn};
use tvix_castore::{
@ -147,12 +148,12 @@ impl PathInfoService for NixHTTPPathInfoService {
warn!(e=%e, "failed to get response body");
io::Error::new(io::ErrorKind::BrokenPipe, e.to_string())
}));
let sync_r = std::io::BufReader::new(tokio_util::io::SyncIoBridge::new(async_r));
let sync_r = tokio_util::io::SyncIoBridge::new(async_r);
// handle decompression, by wrapping the reader.
let mut sync_r: Box<dyn BufRead + Send> = match narinfo.compression {
let sync_r: Box<dyn BufRead + Send> = match narinfo.compression {
Some("none") => Box::new(sync_r),
Some("xz") => Box::new(std::io::BufReader::new(xz2::read::XzDecoder::new(sync_r))),
Some("xz") => Box::new(io::BufReader::new(xz2::read::XzDecoder::new(sync_r))),
Some(comp) => {
return Err(Error::InvalidRequest(
format!("unsupported compression: {}", comp).to_string(),
@ -168,20 +169,55 @@ impl PathInfoService for NixHTTPPathInfoService {
let res = tokio::task::spawn_blocking({
let blob_service = self.blob_service.clone();
let directory_service = self.directory_service.clone();
move || crate::nar::read_nar(&mut sync_r, blob_service, directory_service)
move || -> io::Result<_> {
// Wrap the reader once more, so we can calculate NarSize and NarHash
let mut sync_r = io::BufReader::new(NarReader::from(sync_r));
let root_node = crate::nar::read_nar(&mut sync_r, blob_service, directory_service)?;
let (_, nar_hash, nar_size) = sync_r.into_inner().into_inner();
Ok((root_node, nar_hash, nar_size))
}
})
.await
.unwrap();
match res {
Ok(root_node) => Ok(Some(PathInfo {
node: Some(castorepb::Node {
// set the name of the root node to the digest-name of the store path.
node: Some(root_node.rename(narinfo.store_path.to_string().to_owned().into())),
}),
references: pathinfo.references,
narinfo: pathinfo.narinfo,
})),
Ok((root_node, nar_hash, nar_size)) => {
// ensure the ingested narhash and narsize do actually match.
if narinfo.nar_size != nar_size {
warn!(
narinfo.nar_size = narinfo.nar_size,
http.nar_size = nar_size,
"NARSize mismatch"
);
Err(io::Error::new(
io::ErrorKind::InvalidData,
"NarSize mismatch".to_string(),
))?;
} else if narinfo.nar_hash != nar_hash {
warn!(
narinfo.nar_hash = BASE64.encode(&narinfo.nar_hash),
http.nar_hash = BASE64.encode(&nar_hash),
"NarHash mismatch"
);
Err(io::Error::new(
io::ErrorKind::InvalidData,
"NarHash mismatch".to_string(),
))?;
}
Ok(Some(PathInfo {
node: Some(castorepb::Node {
// set the name of the root node to the digest-name of the store path.
node: Some(
root_node.rename(narinfo.store_path.to_string().to_owned().into()),
),
}),
references: pathinfo.references,
narinfo: pathinfo.narinfo,
}))
}
Err(e) => Err(e.into()),
}
}
@ -211,3 +247,38 @@ impl PathInfoService for NixHTTPPathInfoService {
}))
}
}
/// Small helper reader implementing [std::io::Read].
/// It can be used to wrap another reader, counts the number of bytes read
/// and the sha256 digest of the contents.
struct NarReader<R: Read> {
r: R,
sha256: sha2::Sha256,
bytes_read: u64,
}
impl<R: Read> NarReader<R> {
pub fn from(inner: R) -> Self {
Self {
r: inner,
sha256: Sha256::new(),
bytes_read: 0,
}
}
/// Returns the (remaining) inner reader, the sha256 digest and the number of bytes read.
pub fn into_inner(self) -> (R, [u8; 32], u64) {
(self.r, self.sha256.finalize_fixed().into(), self.bytes_read)
}
}
impl<R: Read> Read for NarReader<R> {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
self.r.read(buf).map(|n| {
self.bytes_read += n as u64;
self.sha256.write_all(&buf[..n]).unwrap();
n
})
}
}