core: add ErrPeerIDMismatch error type to replace ad-hoc errors (#2451)

* feat: add ErrPeerIDMismatch error type to replace ad-hoc errors

* test: add tests demonstrating the ability to discover a peer's peerID during security negotiation

* noise: add tests for ErrPeerIDMismatch

* tls: add error assertions for ErrPeerIDMismatch

---------

Co-authored-by: Marten Seemann <martenseemann@gmail.com>

core/sec/security.go

@@ -3,6 +3,7 @@ package sec
 
 import (
 	"context"
+	"fmt"
 	"net"
 
 	"github.com/libp2p/go-libp2p/core/network"
@@ -29,3 +30,14 @@ type SecureTransport interface {
 	// ID is the protocol ID of the security protocol.
 	ID() protocol.ID
 }
+
+type ErrPeerIDMismatch struct {
+	Expected peer.ID
+	Actual   peer.ID
+}
+
+func (e ErrPeerIDMismatch) Error() string {
+	return fmt.Sprintf("peer id mismatch: expected %s, but remote key matches %s", e.Expected, e.Actual)
+}
+
+var _ error = (*ErrPeerIDMismatch)(nil)

p2p/security/noise/handshake.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/libp2p/go-libp2p/core/crypto"
 	"github.com/libp2p/go-libp2p/core/peer"
+	"github.com/libp2p/go-libp2p/core/sec"
 	"github.com/libp2p/go-libp2p/internal/sha256"
 	"github.com/libp2p/go-libp2p/p2p/security/noise/pb"
 
@@ -276,7 +277,7 @@ func (s *secureSession) handleRemoteHandshakePayload(payload []byte, remoteStati
 
 	// check the peer ID if enabled
 	if s.checkPeerID && s.remoteID != id {
-		return nil, fmt.Errorf("peer id mismatch: expected %s, but remote key matches %s", s.remoteID.Pretty(), id.Pretty())
+		return nil, sec.ErrPeerIDMismatch{Expected: s.remoteID, Actual: id}
 	}
 
 	// verify payload is signed by asserted remote libp2p key.

p2p/security/noise/transport_test.go

@@ -212,7 +212,10 @@ func TestPeerIDMismatchOutboundFailsHandshake(t *testing.T) {
 
 	initErr := <-errChan
 	require.Error(t, initErr, "expected initiator to fail with peer ID mismatch error")
-	require.Contains(t, initErr.Error(), "but remote key matches")
+	var mismatchErr sec.ErrPeerIDMismatch
+	require.ErrorAs(t, initErr, &mismatchErr)
+	require.Equal(t, peer.ID("a-random-peer-id"), mismatchErr.Expected)
+	require.Equal(t, respTransport.localID, mismatchErr.Actual)
 }
 
 func TestPeerIDMismatchInboundFailsHandshake(t *testing.T) {
@@ -231,6 +234,10 @@ func TestPeerIDMismatchInboundFailsHandshake(t *testing.T) {
 
 	_, err := respTransport.SecureInbound(context.Background(), resp, "a-random-peer-id")
 	require.Error(t, err, "expected responder to fail with peer ID mismatch error")
+	var mismatchErr sec.ErrPeerIDMismatch
+	require.ErrorAs(t, err, &mismatchErr)
+	require.Equal(t, peer.ID("a-random-peer-id"), mismatchErr.Expected)
+	require.Equal(t, initTransport.localID, mismatchErr.Actual)
 	<-done
 }
 

p2p/security/tls/crypto.go

@@ -18,6 +18,7 @@ import (
 
 	ic "github.com/libp2p/go-libp2p/core/crypto"
 	"github.com/libp2p/go-libp2p/core/peer"
+	"github.com/libp2p/go-libp2p/core/sec"
 )
 
 const certValidityPeriod = 100 * 365 * 24 * time.Hour // ~100 years
@@ -129,7 +130,7 @@ func (i *Identity) ConfigForPeer(remote peer.ID) (*tls.Config, <-chan ic.PubKey)
 			if err != nil {
 				peerID = peer.ID(fmt.Sprintf("(not determined: %s)", err.Error()))
 			}
-			return fmt.Errorf("peer IDs don't match: expected %s, got %s", remote, peerID)
+			return sec.ErrPeerIDMismatch{Expected: remote, Actual: peerID}
 		}
 		keyCh <- pubKey
 		return nil

p2p/security/tls/transport_test.go

@@ -376,7 +376,10 @@ func TestPeerIDMismatch(t *testing.T) {
 		thirdPartyID, _ := createPeer(t)
 		_, err = clientTransport.SecureOutbound(context.Background(), clientInsecureConn, thirdPartyID)
 		require.Error(t, err)
-		require.Contains(t, err.Error(), "peer IDs don't match")
+		var mismatchErr sec.ErrPeerIDMismatch
+		require.ErrorAs(t, err, &mismatchErr)
+		require.Equal(t, thirdPartyID, mismatchErr.Expected)
+		require.Equal(t, serverID, mismatchErr.Actual)
 
 		var serverErr error
 		select {
@@ -392,8 +395,8 @@ func TestPeerIDMismatch(t *testing.T) {
 		clientInsecureConn, serverInsecureConn := connect(t)
 
 		errChan := make(chan error)
+		thirdPartyID, _ := createPeer(t)
 		go func() {
-			thirdPartyID, _ := createPeer(t)
 			// expect the wrong peer ID
 			_, err := serverTransport.SecureInbound(context.Background(), serverInsecureConn, thirdPartyID)
 			errChan <- err
@@ -412,7 +415,10 @@ func TestPeerIDMismatch(t *testing.T) {
 			t.Fatal("expected handshake to return on the server side")
 		}
 		require.Error(t, serverErr)
-		require.Contains(t, serverErr.Error(), "peer IDs don't match")
+		var mismatchErr sec.ErrPeerIDMismatch
+		require.ErrorAs(t, serverErr, &mismatchErr)
+		require.Equal(t, thirdPartyID, mismatchErr.Expected)
+		require.Equal(t, clientTransport.localPeer, mismatchErr.Actual)
 	})
 }
 

p2p/test/transport/transport_test.go

@@ -20,11 +20,14 @@ import (
 	"github.com/libp2p/go-libp2p/core/host"
 	"github.com/libp2p/go-libp2p/core/network"
 	"github.com/libp2p/go-libp2p/core/peer"
+	"github.com/libp2p/go-libp2p/core/sec"
 	rcmgr "github.com/libp2p/go-libp2p/p2p/host/resource-manager"
 	"github.com/libp2p/go-libp2p/p2p/muxer/yamux"
+	"github.com/libp2p/go-libp2p/p2p/net/swarm"
 	"github.com/libp2p/go-libp2p/p2p/protocol/ping"
 	"github.com/libp2p/go-libp2p/p2p/security/noise"
 	tls "github.com/libp2p/go-libp2p/p2p/security/tls"
+	"github.com/multiformats/go-multiaddr"
 	"github.com/stretchr/testify/require"
 )
 
@@ -607,3 +610,76 @@ func TestStreamReadDeadline(t *testing.T) {
 		})
 	}
 }
+
+func TestDiscoverPeerIDFromSecurityNegotiation(t *testing.T) {
+	// extracts the peerID of the dialed peer from the error
+	extractPeerIDFromError := func(inputErr error) (peer.ID, error) {
+		var dialErr *swarm.DialError
+		if !errors.As(inputErr, &dialErr) {
+			return "", inputErr
+		}
+		innerErr := dialErr.DialErrors[0].Cause
+
+		var peerIDMismatchErr sec.ErrPeerIDMismatch
+		if errors.As(innerErr, &peerIDMismatchErr) {
+			return peerIDMismatchErr.Actual, nil
+		}
+
+		return "", inputErr
+	}
+
+	// runs a test to verify we can extract the peer ID from a target with just its address
+	runTest := func(t *testing.T, h host.Host) {
+		t.Helper()
+		ctx, cancel := context.WithCancel(context.Background())
+		defer cancel()
+
+		// Use a bogus peer ID so that when we connect to the target we get an error telling
+		// us the targets real peer ID
+		bogusPeerId, err := peer.Decode("QmadAdJ3f63JyNs65X7HHzqDwV53ynvCcKtNFvdNaz3nhk")
+		if err != nil {
+			t.Fatal("the hard coded bogus peerID is invalid")
+		}
+
+		ai := &peer.AddrInfo{
+			ID:    bogusPeerId,
+			Addrs: []multiaddr.Multiaddr{h.Addrs()[0]},
+		}
+
+		testHost, err := libp2p.New()
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		// Try connecting with the bogus peer ID
+		if err := testHost.Connect(ctx, *ai); err != nil {
+			// Extract the actual peer ID from the error
+			newPeerId, err := extractPeerIDFromError(err)
+			if err != nil {
+				t.Fatal(err)
+			}
+			ai.ID = newPeerId
+
+			// Make sure the new ID is what we expected
+			if ai.ID != h.ID() {
+				t.Fatalf("peerID mismatch: expected %s, got %s", h.ID(), ai.ID)
+			}
+
+			// and just to double-check try connecting again to make sure it works
+			if err := testHost.Connect(ctx, *ai); err != nil {
+				t.Fatal(err)
+			}
+		} else {
+			t.Fatal("somehow we successfully connected to a bogus peerID!")
+		}
+	}
+
+	for _, tc := range transportsToTest {
+		t.Run(tc.Name, func(t *testing.T) {
+			h := tc.HostGenerator(t, TransportTestCaseOpts{})
+			defer h.Close()
+
+			runTest(t, h)
+		})
+	}
+}