improve error handling in webRTC-related noise function (paritytech#377)

Closes paritytech#43  This PR: 

- [x] eliminates the unsafe assumption and panics in the WebRTC litep2p
config when fetching `Multiaddr`. Ensures litep2p behaves predictably
even with malformed or malicious peers during the handshake phase by
introducing `InvalidMultihash` in the `AddressError`.
- [x] removes assumption about the `reply` buffer size, by checking the
length before splitting in `get_remote_public_key` function.

I am also looking at other functions to see if there should be any
improvement, i will make this a draft PR untill i finish other
improvements or if i find no other improvements needed.

---------

Co-authored-by: Dmitry Markin <[email protected]>

Author: dharjeezy

src/crypto/noise/mod.rs

@@ -164,6 +164,11 @@ impl NoiseContext {
     /// Get remote public key from the received Noise payload.
     #[cfg(feature = "webrtc")]
     pub fn get_remote_public_key(&mut self, reply: &[u8]) -> Result<PublicKey, NegotiationError> {
+        if reply.len() < 2 {
+            tracing::error!(target: LOG_TARGET, "reply too short to contain length prefix");
+            return Err(NegotiationError::ParseError(ParseError::InvalidReplyLength));
+        }
+
         let (len_slice, reply) = reply.split_at(2);
         let len = u16::from_be_bytes(
             len_slice

src/error.rs

@@ -181,6 +181,9 @@ pub enum ParseError {
     /// This error is protocol specific.
     #[error("Invalid data")]
     InvalidData,
+    /// The provided reply length is not valid
+    #[error("Invalid reply length")]
+    InvalidReplyLength,
 }
 
 #[derive(Debug, thiserror::Error)]

src/lib.rs

@@ -55,15 +55,13 @@ use crate::transport::websocket::WebSocketTransport;
 
 use hickory_resolver::{name_server::TokioConnectionProvider, TokioResolver};
 use multiaddr::{Multiaddr, Protocol};
-use multihash::Multihash;
 use transport::Endpoint;
 use types::ConnectionId;
 
-use std::{collections::HashSet, sync::Arc};
-
 pub use bandwidth::BandwidthSink;
 pub use error::Error;
 pub use peer_id::PeerId;
+use std::{collections::HashSet, sync::Arc};
 pub use types::protocol::ProtocolName;
 
 pub(crate) mod peer_id;
@@ -332,9 +330,7 @@ impl Litep2p {
 
             for address in transport_listen_addresses {
                 transport_manager.register_listen_address(address.clone());
-                listen_addresses.push(address.with(Protocol::P2p(
-                    Multihash::from_bytes(&local_peer_id.to_bytes()).unwrap(),
-                )));
+                listen_addresses.push(address.with(Protocol::P2p(*local_peer_id.as_ref())));
             }
 
             transport_manager.register_transport(SupportedTransport::Tcp, Box::new(transport));
@@ -349,9 +345,7 @@ impl Litep2p {
 
             for address in transport_listen_addresses {
                 transport_manager.register_listen_address(address.clone());
-                listen_addresses.push(address.with(Protocol::P2p(
-                    Multihash::from_bytes(&local_peer_id.to_bytes()).unwrap(),
-                )));
+                listen_addresses.push(address.with(Protocol::P2p(*local_peer_id.as_ref())));
             }
 
             transport_manager.register_transport(SupportedTransport::Quic, Box::new(transport));
@@ -366,9 +360,7 @@ impl Litep2p {
 
             for address in transport_listen_addresses {
                 transport_manager.register_listen_address(address.clone());
-                listen_addresses.push(address.with(Protocol::P2p(
-                    Multihash::from_bytes(&local_peer_id.to_bytes()).unwrap(),
-                )));
+                listen_addresses.push(address.with(Protocol::P2p(*local_peer_id.as_ref())));
             }
 
             transport_manager.register_transport(SupportedTransport::WebRtc, Box::new(transport));
@@ -383,9 +375,7 @@ impl Litep2p {
 
             for address in transport_listen_addresses {
                 transport_manager.register_listen_address(address.clone());
-                listen_addresses.push(address.with(Protocol::P2p(
-                    Multihash::from_bytes(&local_peer_id.to_bytes()).unwrap(),
-                )));
+                listen_addresses.push(address.with(Protocol::P2p(*local_peer_id.as_ref())));
             }
 
             transport_manager