fix: add hashing api on comms repo (see issue #4393) (#4429)

Description
--- Add use of hashing API on repo `comms`.

Motivation and Context
--- Tackle issue #4393

How Has This Been Tested?
--- Unit tests

comms/core/src/peer_manager/hashing.rs

@@ -0,0 +1,41 @@
+//  Copyright 2021, The Tari Project
+//
+//  Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
+//  following conditions are met:
+//
+//  1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
+//  disclaimer.
+//
+//  2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
+//  following disclaimer in the documentation and/or other materials provided with the distribution.
+//
+//  3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote
+//  products derived from this software without specific prior written permission.
+//
+//  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+//  INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+//  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+//  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+//  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+//  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
+//  USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+use digest::Digest;
+use tari_crypto::{
+    hash_domain,
+    hashing::{DomainSeparatedHasher, LengthExtensionAttackResistant},
+};
+
+hash_domain!(
+    CommsCorePeerManagerDomain,
+    "com.tari.tari_project.comms.core.peer_manager",
+    1
+);
+
+pub(crate) const IDENTITY_SIGNATURE: &str = "identity_signature";
+
+pub(crate) fn comms_core_peer_manager_domain<D: Digest + LengthExtensionAttackResistant>(
+    label: &'static str,
+) -> DomainSeparatedHasher<D, CommsCorePeerManagerDomain> {
+    DomainSeparatedHasher::<D, CommsCorePeerManagerDomain>::new_with_label(label)
+}

comms/core/src/peer_manager/identity_signature.rs

@@ -23,13 +23,13 @@
 use std::convert::{TryFrom, TryInto};
 
 use chrono::{DateTime, NaiveDateTime, Utc};
-use digest::Digest;
 use prost::Message;
 use rand::rngs::OsRng;
 use serde::{Deserialize, Serialize};
-use tari_crypto::keys::PublicKey as PublicKeyTrait;
+use tari_crypto::{hashing::DomainSeparatedHasher, keys::PublicKey as PublicKeyTrait};
 use tari_utilities::ByteArray;
 
+use super::hashing::{comms_core_peer_manager_domain, CommsCorePeerManagerDomain, IDENTITY_SIGNATURE};
 use crate::{
     message::MessageExt,
     multiaddr::Multiaddr,
@@ -73,8 +73,9 @@ impl IdentitySignature {
             features,
             addresses,
             updated_at,
-        );
-        let signature = Signature::sign(secret_key.clone(), secret_nonce, &challenge.finalize())
+        )
+        .finalize();
+        let signature = Signature::sign(secret_key.clone(), secret_nonce, challenge.as_ref())
             .expect("unreachable panic: challenge hash digest is the correct length");
         Self {
             version: Self::LATEST_VERSION,
@@ -125,8 +126,9 @@ impl IdentitySignature {
             features,
             addresses,
             self.updated_at,
-        );
-        self.signature.verify_challenge(public_key, &challenge.finalize())
+        )
+        .finalize();
+        self.signature.verify_challenge(public_key, challenge.as_ref())
     }
 
     fn construct_challenge<'a, I: IntoIterator<Item = &'a Multiaddr>>(
@@ -136,9 +138,9 @@ impl IdentitySignature {
         features: PeerFeatures,
         addresses: I,
         updated_at: DateTime<Utc>,
-    ) -> CommsChallenge {
+    ) -> DomainSeparatedHasher<CommsChallenge, CommsCorePeerManagerDomain> {
         // e = H(P||R||m)
-        let challenge = CommsChallenge::new()
+        let challenge = comms_core_peer_manager_domain::<CommsChallenge>(IDENTITY_SIGNATURE)
             .chain(public_key.as_bytes())
             .chain(public_nonce.as_bytes())
             .chain(version.to_le_bytes())

comms/core/src/peer_manager/mod.rs

@@ -78,6 +78,8 @@ pub use error::PeerManagerError;
 mod identity_signature;
 pub use identity_signature::IdentitySignature;
 
+mod hashing;
+
 pub mod node_id;
 pub use node_id::NodeId;
 

comms/dht/src/dedup/mod.rs

@@ -33,6 +33,10 @@ use digest::Digest;
 use futures::{future::BoxFuture, task::Context};
 use log::*;
 use tari_comms::{pipeline::PipelineError, types::CommsChallenge};
+use tari_crypto::{
+    hash_domain,
+    hashing::{DomainSeparatedHasher, LengthExtensionAttackResistant},
+};
 use tari_utilities::hex::Hex;
 use tower::{layer::Layer, Service, ServiceExt};
 
@@ -42,17 +46,29 @@ use crate::{
 };
 
 const LOG_TARGET: &str = "comms::dht::dedup";
+const DEDUP_MESSAGE_HASH_LABEL: &str = "dedup.meesage_hash";
+
+hash_domain!(CommsDhtDedupDomain, "com.tari.tari_project.comms.dht", 1);
+
+fn comms_dht_dedup_message_hash<D: Digest + LengthExtensionAttackResistant>(
+    label: &'static str,
+) -> DomainSeparatedHasher<D, CommsDhtDedupDomain> {
+    DomainSeparatedHasher::<D, CommsDhtDedupDomain>::new_with_label(label)
+}
 
 pub fn hash_inbound_message(msg: &DhtInboundMessage) -> [u8; 32] {
     create_message_hash(&msg.dht_header.message_signature, &msg.body)
 }
 
 pub fn create_message_hash(message_signature: &[u8], body: &[u8]) -> [u8; 32] {
-    CommsChallenge::new()
+    let result = comms_dht_dedup_message_hash::<CommsChallenge>(DEDUP_MESSAGE_HASH_LABEL)
         .chain(message_signature)
         .chain(&body)
-        .finalize()
-        .into()
+        .finalize();
+
+    let mut out = [0u8; 32];
+    out.copy_from_slice(result.as_ref());
+    out
 }
 
 /// # DHT Deduplication middleware
@@ -197,7 +213,7 @@ mod test {
     #[test]
     fn deterministic_hash() {
         const TEST_MSG: &[u8] = b"test123";
-        const EXPECTED_HASH: &str = "90cccd774db0ac8c6ea2deff0e26fc52768a827c91c737a2e050668d8c39c224";
+        const EXPECTED_HASH: &str = "d6333668f259f677703fbe4e89152ee41c7c01f6dec502befc63120246523ffe";
 
         let node_identity = make_node_identity();
         let dht_message = make_dht_inbound_message(