fix: add i,j params size limitation

Author: ygurov

device/awg/special_handshake_handler.go

@@ -31,12 +31,12 @@ type SpecialHandshakeHandler struct {
 	IsSet bool
 }
 
-func (handler *SpecialHandshakeHandler) Validate() error {
+func (handler *SpecialHandshakeHandler) Validate(maxSegmentSize int) error {
 	var errs []error
-	if err := handler.SpecialJunk.Validate(); err != nil {
+	if err := handler.SpecialJunk.Validate(maxSegmentSize); err != nil {
 		errs = append(errs, err)
 	}
-	if err := handler.ControlledJunk.Validate(); err != nil {
+	if err := handler.ControlledJunk.Validate(maxSegmentSize); err != nil {
 		errs = append(errs, err)
 	}
 	return errors.Join(errs...)

device/awg/tag_junk_packet_generator.go

@@ -57,3 +57,7 @@ func (tg *TagJunkPacketGenerator) IpcGetFields() IpcFields {
 		Value: tg.tagValue,
 	}
 }
+
+func (tg *TagJunkPacketGenerator) Size() int {
+	return tg.packetSize
+}

device/awg/tag_junk_packet_generators.go

@@ -1,6 +1,8 @@
 package awg
 
-import "fmt"
+import (
+	"fmt"
+)
 
 type TagJunkPacketGenerators struct {
 	tagGenerators    []TagJunkPacketGenerator
@@ -20,7 +22,7 @@ func (generators *TagJunkPacketGenerators) IsDefined() bool {
 }
 
 // validate that packets were defined consecutively
-func (generators *TagJunkPacketGenerators) Validate() error {
+func (generators *TagJunkPacketGenerators) Validate(maxSegmentSize int) error {
 	seen := make([]bool, len(generators.tagGenerators))
 	for _, generator := range generators.tagGenerators {
 		index, err := generator.nameIndex()
@@ -32,6 +34,10 @@ func (generators *TagJunkPacketGenerators) Validate() error {
 		} else {
 			seen[index-1] = true
 		}
+
+		if generator.Size() > maxSegmentSize {
+			return fmt.Errorf("junk packet %s must not exceed %d bytes", generator.name, maxSegmentSize)
+		}
 	}
 
 	for _, found := range seen {

device/awg/tag_junk_packet_generators_test.go

@@ -91,7 +91,7 @@ func TestTagJunkGeneratorHandlerValidate(t *testing.T) {
 				generators.AppendGenerator(gen)
 			}
 
-			err := generators.Validate()
+			err := generators.Validate(1500)
 			if tt.wantErr {
 				require.Error(t, err)
 				require.Contains(t, err.Error(), tt.errMsg)

device/device.go

@@ -819,7 +819,7 @@ func (device *Device) handlePostConfig(tempAwg *awg.Protocol) error {
 	}
 
 	if tempAwg.HandshakeHandler.IsSet {
-		if err := tempAwg.HandshakeHandler.Validate(); err != nil {
+		if err := tempAwg.HandshakeHandler.Validate(MaxSegmentSize); err != nil {
 			errs = append(errs, ipcErrorf(
 				ipc.IpcErrorInvalid, "handshake handler validate: %w", err))
 		} else {

device/uapi.go

@@ -406,26 +406,26 @@ func (device *Device) handleDeviceLine(key, value string, tempAwg *awg.Protocol)
 			return nil
 		}
 
-		generators, err := awg.Parse(key, value)
+		generator, err := awg.Parse(key, value)
 		if err != nil {
 			return ipcErrorf(ipc.IpcErrorInvalid, "invalid %s: %w", key, err)
 		}
 		device.log.Verbosef("UAPI: Updating %s", key)
-		tempAwg.HandshakeHandler.SpecialJunk.AppendGenerator(generators)
+		tempAwg.HandshakeHandler.SpecialJunk.AppendGenerator(generator)
 		tempAwg.HandshakeHandler.IsSet = true
 	case "j1", "j2", "j3":
 		if len(value) == 0 {
 			device.log.Verbosef("UAPI: received empty %s", key)
 			return nil
 		}
 
-		generators, err := awg.Parse(key, value)
+		generator, err := awg.Parse(key, value)
 		if err != nil {
 			return ipcErrorf(ipc.IpcErrorInvalid, "invalid %s: %w", key, err)
 		}
 		device.log.Verbosef("UAPI: Updating %s", key)
 
-		tempAwg.HandshakeHandler.ControlledJunk.AppendGenerator(generators)
+		tempAwg.HandshakeHandler.ControlledJunk.AppendGenerator(generator)
 		tempAwg.HandshakeHandler.IsSet = true
 	case "itime":
 		if len(value) == 0 {