From 0d67b37d963f5df5e01ab589c3b7a198e8480425 Mon Sep 17 00:00:00 2001
From: hwipl <33433250+hwipl@users.noreply.github.com>
Date: Tue, 12 Mar 2024 18:05:52 +0100
Subject: [PATCH 1/3] Increase maximum payload length in Unix Socket API
 message

Increase the maximum payload length in the Unix Socket API message from
32768 bytes to 2097152 bytes.

Signed-off-by: hwipl <33433250+hwipl@users.noreply.github.com>
---
 internal/api/message.go | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/internal/api/message.go b/internal/api/message.go
index a1f4207..59586d7 100644
--- a/internal/api/message.go
+++ b/internal/api/message.go
@@ -8,7 +8,7 @@ import (
 
 const (
 	// MaxPayloadLength is the maximum allowed length of a message payload.
-	MaxPayloadLength = 32768
+	MaxPayloadLength = 2097152
 )
 
 // Message types.
@@ -23,7 +23,7 @@ const (
 // Header is a message header.
 type Header struct {
 	Type   uint16
-	Length uint16
+	Length uint32
 }
 
 // Message is an API message.
@@ -40,7 +40,7 @@ func NewMessage(t uint16, p []byte) *Message {
 	return &Message{
 		Header: Header{
 			Type:   t,
-			Length: uint16(len(p)),
+			Length: uint32(len(p)),
 		},
 		Value: p,
 	}

From 808b5fd788bbb638ae2e2b9bd0c6d2eb702df15d Mon Sep 17 00:00:00 2001
From: hwipl <33433250+hwipl@users.noreply.github.com>
Date: Tue, 12 Mar 2024 18:09:28 +0100
Subject: [PATCH 2/3] Check if API message creation was successful in
 vpncscript

Signed-off-by: hwipl <33433250+hwipl@users.noreply.github.com>
---
 internal/vpncscript/client.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/internal/vpncscript/client.go b/internal/vpncscript/client.go
index c62b779..d3b2830 100644
--- a/internal/vpncscript/client.go
+++ b/internal/vpncscript/client.go
@@ -26,6 +26,9 @@ func runClient(socketFile string, configUpdate *daemon.VPNConfigUpdate) error {
 		return fmt.Errorf("VPNCScript could not convert config update to JSON: %w", err)
 	}
 	msg := api.NewMessage(api.TypeVPNConfigUpdate, b)
+	if msg == nil {
+		return fmt.Errorf("VPNCScript could not create message: invalid message")
+	}
 	err = api.WriteMessage(conn, msg)
 	if err != nil {
 		return fmt.Errorf("VPNCScript could not send message to Daemon: %w", err)

From 084b1777222fe8a78ee804e22d79992c574f6d30 Mon Sep 17 00:00:00 2001
From: hwipl <33433250+hwipl@users.noreply.github.com>
Date: Tue, 12 Mar 2024 18:10:50 +0100
Subject: [PATCH 3/3] Add maximum payload length tests to vpncscript

Signed-off-by: hwipl <33433250+hwipl@users.noreply.github.com>
---
 internal/vpncscript/client_test.go | 54 ++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/internal/vpncscript/client_test.go b/internal/vpncscript/client_test.go
index ca448ac..65e45c6 100644
--- a/internal/vpncscript/client_test.go
+++ b/internal/vpncscript/client_test.go
@@ -2,10 +2,12 @@ package vpncscript
 
 import (
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"github.com/telekom-mms/oc-daemon/internal/api"
 	"github.com/telekom-mms/oc-daemon/internal/daemon"
+	"github.com/telekom-mms/oc-daemon/pkg/vpnconfig"
 )
 
 // TestRunClient tests runClient.
@@ -44,4 +46,56 @@ func TestRunClient(t *testing.T) {
 		t.Fatal(err)
 	}
 	server.Stop()
+
+	// helper for config update creation
+	getConfUpdate := func(length int) *daemon.VPNConfigUpdate {
+		exclude := "a.too.long.example.com"
+		conf := vpnconfig.New()
+		conf.Split.ExcludeDNS = []string{exclude}
+		confUpdate := daemon.NewVPNConfigUpdate()
+		confUpdate.Config = conf
+
+		// check length
+		b, err := confUpdate.JSON()
+		if err != nil {
+			t.Fatal(err)
+		}
+		n := length - len(b)
+
+		// increase length to maximum
+		exclude = strings.Repeat("a", n) + exclude
+		conf.Split.ExcludeDNS = []string{exclude}
+
+		return confUpdate
+	}
+
+	// test with maximum payload length
+	server = api.NewServer(config)
+	go func() {
+		for r := range server.Requests() {
+			r.Close()
+		}
+	}()
+	if err := server.Start(); err != nil {
+		t.Fatal(err)
+	}
+	if err := runClient(sockfile, getConfUpdate(api.MaxPayloadLength)); err != nil {
+		t.Fatal(err)
+	}
+	server.Stop()
+
+	// test with more than maximum payload length
+	server = api.NewServer(config)
+	go func() {
+		for r := range server.Requests() {
+			r.Close()
+		}
+	}()
+	if err := server.Start(); err != nil {
+		t.Fatal(err)
+	}
+	if err := runClient(sockfile, getConfUpdate(api.MaxPayloadLength+1)); err == nil {
+		t.Fatal("too long message should return error")
+	}
+	server.Stop()
 }