update: allow config files set address validation

address_validator.go

@@ -0,0 +1,56 @@
+package water
+
+import (
+	"errors"
+)
+
+var (
+	ErrAddressValidatorNotInitialized = errors.New("address validator not initialized properly")
+	ErrAddressValidationDenied        = errors.New("address validation denied")
+)
+
+type addressValidator struct {
+	catchAll  bool
+	allowlist map[string][]string // map[address]networks
+	denylist  map[string][]string // map[address]networks
+}
+
+func (a *addressValidator) validate(network, address string) error {
+	if a.catchAll {
+		// only check denylist, otherwise allow
+		if a.denylist == nil {
+			return ErrAddressValidatorNotInitialized
+		}
+
+		if deniedNetworks, ok := a.denylist[address]; ok {
+			if deniedNetworks == nil {
+				return ErrAddressValidatorNotInitialized
+			}
+
+			for _, deniedNet := range deniedNetworks {
+				if deniedNet == network {
+					return ErrAddressValidationDenied
+				}
+			}
+		}
+		return nil
+	} else {
+		// only check allowlist, otherwise deny
+		if a.allowlist == nil {
+			return ErrAddressValidatorNotInitialized
+		}
+
+		if allowedNetworks, ok := a.allowlist[address]; ok {
+			if allowedNetworks == nil {
+				return ErrAddressValidatorNotInitialized
+			}
+
+			for _, allowedNet := range allowedNetworks {
+				if allowedNet == network {
+					return nil
+				}
+			}
+		}
+		return ErrAddressValidationDenied
+	}
+}

address_validator_test.go

@@ -0,0 +1,75 @@
+package water
+
+// package water instead of water_test to access unexported struct addressValidator and its unexported fields/methods
+
+import "testing"
+
+func Test_addressValidator_validate(t *testing.T) {
+	var a addressValidator
+
+	// test catchAll with nil denylist
+	a.catchAll = true
+
+	if err := a.validate("random net", "random address"); err != ErrAddressValidatorNotInitialized {
+		t.Errorf("Expected ErrAddressValidatorNotInitialized, got %v", err)
+	}
+
+	// test nil denylist entry
+	a.denylist = map[string][]string{
+		"denied address": nil,
+	}
+
+	if err := a.validate("random net", "denied address"); err != ErrAddressValidatorNotInitialized {
+		t.Errorf("Expected ErrAddressValidatorNotInitialized, got %v", err)
+	}
+
+	// test denied address on denied network
+	a.denylist["denied address"] = []string{"denied net"}
+
+	if err := a.validate("denied net", "denied address"); err != ErrAddressValidationDenied {
+		t.Errorf("Expected ErrAddressValidationDenied, got %v", err)
+	}
+
+	// test random network with denied address
+	if err := a.validate("random net", "denied address"); err != nil {
+		t.Errorf("Expected nil, got %v", err)
+	}
+
+	// test random address on denied network
+	if err := a.validate("denied net", "random address"); err != nil {
+		t.Errorf("Expected nil, got %v", err)
+	}
+
+	// test not catchAll with nil allowlist
+	a.catchAll = false
+
+	if err := a.validate("random net", "random address"); err != ErrAddressValidatorNotInitialized {
+		t.Errorf("Expected ErrAddressValidatorNotInitialized, got %v", err)
+	}
+
+	// test nil allowlist entry
+	a.allowlist = map[string][]string{
+		"allowed address": nil,
+	}
+
+	if err := a.validate("random net", "allowed address"); err != ErrAddressValidatorNotInitialized {
+		t.Errorf("Expected ErrAddressValidatorNotInitialized, got %v", err)
+	}
+
+	// test allowed address on allowed network
+	a.allowlist["allowed address"] = []string{"allowed net"}
+
+	if err := a.validate("allowed net", "allowed address"); err != nil {
+		t.Errorf("Expected nil, got %v", err)
+	}
+
+	// test random network with allowed address
+	if err := a.validate("random net", "allowed address"); err != ErrAddressValidationDenied {
+		t.Errorf("Expected ErrAddressValidationDenied, got %v", err)
+	}
+
+	// test random address on allowed network
+	if err := a.validate("allowed net", "random address"); err != ErrAddressValidationDenied {
+		t.Errorf("Expected ErrAddressValidationDenied, got %v", err)
+	}
+}

config.go

@@ -204,6 +204,16 @@ func (c *Config) UnmarshalJSON(data []byte) error {
 		}
 	}
 
+	if c.DialedAddressValidator == nil {
+		a := &addressValidator{
+			catchAll:  confJson.Network.AddressValidation.CatchAll,
+			allowlist: confJson.Network.AddressValidation.Allowlist,
+			denylist:  confJson.Network.AddressValidation.Denylist,
+		}
+
+		c.DialedAddressValidator = a.validate
+	}
+
 	if len(confJson.Network.Listener.Network) > 0 && len(confJson.Network.Listener.Address) > 0 {
 		c.NetworkListener, err = net.Listen(confJson.Network.Listener.Network, confJson.Network.Listener.Address)
 		if err != nil {
@@ -281,6 +291,31 @@ func (c *Config) UnmarshalProto(b []byte) error {
 		c.TransportModuleConfig = TransportModuleConfigFromBytes(confProto.GetTransportModule().GetConfig())
 	}
 
+	// Parse DialedAddressValidator if not already set
+	if c.DialedAddressValidator == nil {
+		a := &addressValidator{
+			catchAll: confProto.GetNetwork().GetAddressValidation().GetCatchAll(),
+		}
+
+		allowlist := confProto.GetNetwork().GetAddressValidation().GetAllowlist()
+		if len(allowlist) > 0 {
+			a.allowlist = make(map[string][]string)
+			for k, v := range allowlist {
+				a.allowlist[k] = v.GetNames()
+			}
+		}
+
+		denylist := confProto.GetNetwork().GetAddressValidation().GetDenylist()
+		if len(denylist) > 0 {
+			a.denylist = make(map[string][]string)
+			for k, v := range denylist {
+				a.denylist[k] = v.GetNames()
+			}
+		}
+
+		c.DialedAddressValidator = a.validate
+	}
+
 	// Parse NetworkListener
 	listenerNetwork, listenerAddress := confProto.GetNetwork().GetListener().GetNetwork(), confProto.GetNetwork().GetListener().GetAddress()
 	if len(listenerNetwork) > 0 && len(listenerAddress) > 0 {

configbuilder/config.json.go

@@ -12,6 +12,11 @@ type ConfigJSON struct {
 
 	Network struct {
 		// DialerFunc string `json:"dialer_func,omitempty"` // we have no good way to represent a func in JSON format yet
+		AddressValidation struct {
+			CatchAll  bool                `json:"catch_all,omitempty"` // If set, will allow all unspecified addresses. Otherwise, unspecified addresses will be rejected.
+			Allowlist map[string][]string `json:"allowlist,omitempty"` // e.g. {"1.1.1.1:443": ["tcp", "udp"], "1.0.0.1:443": ["tcp"], ...}
+			Denylist  map[string][]string `json:"denylist,omitempty"`  // e.g. {"1.0.0.0:80": ["udp"], ...}
+		} `json:"address_validator,omitempty"`
 		Listener struct {
 			Network string `json:"network"` // e.g. "tcp"
 			Address string `json:"address"` // e.g. "0.0.0.0:0"