Gateway Evaluate() with transient data

Add protection logic to ensure sensitive transient data is not unintentionally leaked to other org’s peers when evaluating transaction proposal.
If transient data is present and target_organizations is not specified, send request only to a local peer, or fail if one is not available for that channel/chaincode

Signed-off-by: andrew-coleman <andrew_coleman@uk.ibm.com>

internal/pkg/gateway/api.go

@@ -32,7 +32,7 @@ func (gs *Server) Evaluate(ctx context.Context, request *gp.EvaluateRequest) (*g
 		return nil, status.Error(codes.InvalidArgument, "an evaluate request is required")
 	}
 	signedProposal := request.GetProposedTransaction()
-	channel, chaincodeID, _, err := getChannelAndChaincodeFromSignedProposal(signedProposal)
+	channel, chaincodeID, hasTransientData, err := getChannelAndChaincodeFromSignedProposal(signedProposal)
 	if err != nil {
 		return nil, status.Errorf(codes.InvalidArgument, "failed to unpack transaction proposal: %s", err)
 	}
@@ -42,8 +42,18 @@ func (gs *Server) Evaluate(ctx context.Context, request *gp.EvaluateRequest) (*g
 		return nil, status.Errorf(codes.Unavailable, "%s", err)
 	}
 
-	endorser, err := gs.registry.evaluator(channel, chaincodeID, request.GetTargetOrganizations())
+	targetOrgs := request.GetTargetOrganizations()
+	transientProtected := false
+	if hasTransientData && targetOrgs == nil {
+		targetOrgs = []string{gs.registry.localEndorser.mspid}
+		transientProtected = true
+	}
+
+	endorser, err := gs.registry.evaluator(channel, chaincodeID, targetOrgs)
 	if err != nil {
+		if transientProtected {
+			return nil, status.Error(codes.Unavailable, "no endorsers found in the gateway's organization; retry specifying target organization(s) to protect transient data")
+		}
 		return nil, status.Errorf(codes.Unavailable, "%s", err)
 	}
 

internal/pkg/gateway/api_test.go

@@ -233,6 +233,41 @@ func TestEvaluate(t *testing.T) {
 			endorsingOrgs:     []string{"msp2", "msp3"},
 			expectedEndorsers: []string{"peer4:11051"},
 		},
+		{
+			name: "evaluate with transient data should select local org, highest block height",
+			members: []networkMember{
+				{"id1", "localhost:7051", "msp1", 4},
+				{"id2", "peer1:8051", "msp1", 5},
+				{"id3", "peer2:9051", "msp2", 6},
+				{"id4", "peer3:10051", "msp2", 5},
+				{"id5", "peer4:11051", "msp3", 7},
+			},
+			transientData:     map[string][]byte{"transient-key": []byte("transient-value")},
+			expectedEndorsers: []string{"peer1:8051"},
+		},
+		{
+			name: "evaluate with transient data should fail if local org not available",
+			members: []networkMember{
+				{"id3", "peer2:9051", "msp2", 6},
+				{"id4", "peer3:10051", "msp2", 5},
+				{"id5", "peer4:11051", "msp3", 7},
+			},
+			transientData: map[string][]byte{"transient-key": []byte("transient-value")},
+			errString:     "rpc error: code = Unavailable desc = no endorsers found in the gateway's organization; retry specifying target organization(s) to protect transient data",
+		},
+		{
+			name: "evaluate with transient data and target (non-local) orgs should select the highest block height peer",
+			members: []networkMember{
+				{"id1", "localhost:7051", "msp1", 11},
+				{"id2", "peer1:8051", "msp1", 5},
+				{"id3", "peer2:9051", "msp2", 6},
+				{"id4", "peer3:10051", "msp2", 9},
+				{"id5", "peer4:11051", "msp3", 7},
+			},
+			transientData:     map[string][]byte{"transient-key": []byte("transient-value")},
+			endorsingOrgs:     []string{"msp2", "msp3"},
+			expectedEndorsers: []string{"peer3:10051"},
+		},
 		{
 			name: "process proposal fails",
 			members: []networkMember{