From cb68bf9e0c073aa060b3fe6d9aa14bbfaebc5dae Mon Sep 17 00:00:00 2001
From: Devin Ragotzy <devin.ragotzy@gmail.com>
Date: Tue, 18 Aug 2020 14:32:38 -0400
Subject: [PATCH] Use ring crate to generate StatHashes when saving
 stateid/statehash

---
 Cargo.lock            |  1 +
 Cargo.toml            |  2 +-
 src/database/rooms.rs | 20 ++++++++++++--------
 src/utils.rs          |  2 +-
 4 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index ffee8ea..faa9e89 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -295,6 +295,7 @@ dependencies = [
  "log",
  "rand",
  "reqwest",
+ "ring",
  "rocket",
  "ruma",
  "rust-argon2 0.8.2",
diff --git a/Cargo.toml b/Cargo.toml
index 4c14d71..78d8f76 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -33,7 +33,7 @@ image = { version = "0.23.4", default-features = false, features = ["jpeg", "png
 base64 = "0.12.3" # Used to encode server public key
 # state-res = { path = "../../state-res" }
 state-res = { git = "https://github.com/ruma/state-res", version = "0.1.0" }
-
+ring = "0.16.15"
 
 [features]
 default = ["conduit_bin"]
diff --git a/src/database/rooms.rs b/src/database/rooms.rs
index 0d36326..6366c8c 100644
--- a/src/database/rooms.rs
+++ b/src/database/rooms.rs
@@ -4,6 +4,7 @@ pub use edus::RoomEdus;
 
 use crate::{pdu::PduBuilder, utils, Error, PduEvent, Result};
 use log::error;
+use ring::digest;
 use ruma::{
     api::client::error::ErrorKind,
     events::{
@@ -21,9 +22,8 @@ use sled::IVec;
 use state_res::{event_auth, Requester, StateEvent, StateMap, StateStore};
 
 use std::{
-    collections::{hash_map::DefaultHasher, BTreeMap, HashMap},
+    collections::{BTreeMap, HashMap},
     convert::{TryFrom, TryInto},
-    hash::{Hash, Hasher},
     mem,
     result::Result as StdResult,
 };
@@ -285,8 +285,10 @@ impl Rooms {
             .next()
             .is_none()
         {
-            // TODO use ring crate to hash
-            return Ok(room_id.as_str().to_owned());
+            return utils::string_from_bytes(
+                digest::digest(&digest::SHA256, room_id.as_bytes()).as_ref(),
+            )
+            .map_err(|_| Error::bad_database("Empty state generated invalid string from hash."));
         }
 
         let pdu_ids_to_hash = self
@@ -304,11 +306,13 @@ impl Rooms {
                     .collect::<Result<Vec<Vec<u8>>>>()
             })??;
 
-        let mut hasher = DefaultHasher::new();
-        pdu_ids_to_hash.hash(&mut hasher);
-        let hash = hasher.finish().to_string();
+        let hash = digest::digest(
+            &digest::SHA256,
+            &pdu_ids_to_hash.into_iter().flatten().collect::<Vec<u8>>(),
+        );
         // TODO not sure how you want to hash this
-        Ok(hash)
+        utils::string_from_bytes(hash.as_ref())
+            .map_err(|_| Error::bad_database("State generated invalid string from hash."))
     }
 
     /// Checks if a room exists.
diff --git a/src/utils.rs b/src/utils.rs
index 77a7d1f..b549153 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -94,5 +94,5 @@ pub fn common_elements(
 
 pub fn deserialize<'de, T: serde::Deserialize<'de>>(val: &'de sled::IVec) -> Result<T, Error> {
     serde_json::from_slice::<T>(val.as_ref())
-        .map_err(|_| Error::bad_database("PDU in db is invalid."))
+        .map_err(|_| Error::bad_database("Found invalid bytes as PDU in db."))
 }