From 13afd8cc7588abb4adcf584f7983c1b93ae70f9d Mon Sep 17 00:00:00 2001
From: iliana etaoin <iliana@oxide.computer>
Date: Thu, 31 Oct 2024 14:51:50 -0700
Subject: [PATCH] replace ring with sha2 (#67)

---
 Cargo.toml    |  2 +-
 src/blob.rs   | 10 +++++-----
 src/digest.rs | 12 +++++++-----
 3 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 565e5d3..a6f130e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -25,11 +25,11 @@ futures = "0.3"
 futures-util = "0.3"
 hex = "0.4.3"
 reqwest = { version = "0.12", default-features = false, features = ["rustls-tls", "stream"] }
-ring = "0.16.20"
 semver = { version = "1.0.17", features = ["std", "serde"] }
 serde = { version = "1.0", features = [ "derive" ] }
 serde_derive = "1.0"
 serde_json = "1.0"
+sha2 = "0.10.8"
 slog = "2.7"
 tar = "0.4"
 thiserror = "1.0"
diff --git a/src/blob.rs b/src/blob.rs
index 042443f..86b86e7 100644
--- a/src/blob.rs
+++ b/src/blob.rs
@@ -9,8 +9,8 @@ use camino::{Utf8Path, Utf8PathBuf};
 use chrono::{DateTime, FixedOffset, Utc};
 use futures_util::StreamExt;
 use reqwest::header::{CONTENT_LENGTH, LAST_MODIFIED};
-use ring::digest::{Context as DigestContext, Digest, SHA256};
 use serde::{Deserialize, Serialize};
+use sha2::{Digest, Sha256};
 use std::str::FromStr;
 use tokio::io::{AsyncReadExt, AsyncWriteExt, BufReader};
 
@@ -173,13 +173,13 @@ pub async fn download(
     Ok(())
 }
 
-async fn get_sha256_digest(path: &Utf8Path) -> Result<Digest> {
+async fn get_sha256_digest(path: &Utf8Path) -> Result<[u8; 32]> {
     let mut reader = BufReader::new(
         tokio::fs::File::open(path)
             .await
             .with_context(|| format!("could not open {path:?}"))?,
     );
-    let mut context = DigestContext::new(&SHA256);
+    let mut hasher = Sha256::new();
     let mut buffer = [0; 1024];
 
     loop {
@@ -190,10 +190,10 @@ async fn get_sha256_digest(path: &Utf8Path) -> Result<Digest> {
         if count == 0 {
             break;
         } else {
-            context.update(&buffer[..count]);
+            hasher.update(&buffer[..count]);
         }
     }
-    Ok(context.finish())
+    Ok(hasher.finalize().into())
 }
 
 #[test]
diff --git a/src/digest.rs b/src/digest.rs
index 27b3705..25cc255 100644
--- a/src/digest.rs
+++ b/src/digest.rs
@@ -9,8 +9,8 @@ use async_trait::async_trait;
 use blake3::{Hash as BlakeDigest, Hasher as BlakeHasher};
 use camino::Utf8Path;
 use hex::ToHex;
-use ring::digest::{Context as DigestContext, Digest as ShaDigest, SHA256};
 use serde::{Deserialize, Serialize};
+use sha2::{Digest as _, Sha256};
 use tokio::io::{AsyncReadExt, BufReader};
 
 // The buffer size used to hash smaller files.
@@ -22,6 +22,8 @@ const HASH_BUFFER_SIZE: usize = 16 * (1 << 10);
 // NOTE: This is currently only blake3-specific.
 const LARGE_HASH_SIZE: usize = 1 << 20;
 
+struct ShaDigest([u8; 32]);
+
 /// Implemented by algorithms which can take digests of files.
 #[async_trait]
 pub trait FileDigester {
@@ -36,7 +38,7 @@ impl FileDigester for ShaDigest {
                 .await
                 .with_context(|| format!("could not open {path:?}"))?,
         );
-        let mut context = DigestContext::new(&SHA256);
+        let mut hasher = Sha256::new();
         let mut buffer = [0; HASH_BUFFER_SIZE];
         loop {
             let count = reader
@@ -46,10 +48,10 @@ impl FileDigester for ShaDigest {
             if count == 0 {
                 break;
             } else {
-                context.update(&buffer[..count]);
+                hasher.update(&buffer[..count]);
             }
         }
-        let digest = context.finish().into();
+        let digest = ShaDigest(hasher.finalize().into()).into();
 
         Ok(digest)
     }
@@ -106,7 +108,7 @@ pub enum Digest {
 
 impl From<ShaDigest> for Digest {
     fn from(digest: ShaDigest) -> Self {
-        Self::Sha2(digest.as_ref().encode_hex::<String>())
+        Self::Sha2(digest.0.as_ref().encode_hex::<String>())
     }
 }