Initial Commit

entry.go

@@ -0,0 +1,4 @@
+package main
+
+func main() {
+}

go.mod

@@ -0,0 +1,3 @@
+module Wordifier
+
+go 1.18

word/macroeditor.go

@@ -0,0 +1,81 @@
+package word
+
+import (
+	zip2 "archive/zip"
+	"bytes"
+	"io"
+	"io/ioutil"
+	"os"
+)
+
+type (
+	MacroInjectTarget struct {
+		Name        string
+		Marker      []byte
+		Replacement []byte
+	}
+)
+
+func NewMacroInjectTarget(name string, marker []byte, replacement []byte) MacroInjectTarget {
+	if len(replacement) != len(marker) {
+		panic("Payload and target are not the same size. Make sure replacement is the same length as marker")
+	}
+	return MacroInjectTarget{name, marker, replacement}
+}
+
+func CopyZipWithReplacements(src string, dest io.Writer, replacements []MacroInjectTarget) {
+	inf, err := os.OpenFile(src, os.O_RDONLY, 0755)
+	if err != nil {
+		panic(err)
+	}
+	defer inf.Close()
+
+	infInfo, err := inf.Stat()
+	if err != nil {
+		panic(err)
+	}
+
+	zReader, err := zip2.NewReader(inf, infInfo.Size())
+	if err != nil {
+		panic(err)
+	}
+
+	zWriter := zip2.NewWriter(dest)
+	defer zWriter.Flush()
+	defer zWriter.Close()
+
+	for _, file := range zReader.File {
+		modified := false
+		for _, rule := range replacements {
+			if file.Name == rule.Name {
+				modified = true
+				container, err := zWriter.Create(file.Name)
+				if err != nil {
+					panic(err)
+				}
+				alternateContent := modifyEntry(file, rule)
+				_, err = container.Write(*alternateContent)
+				if err != nil {
+					panic(err)
+				}
+			}
+		}
+		if !modified {
+			zWriter.Copy(file)
+		}
+	}
+}
+
+func modifyEntry(f *zip2.File, injectionTarget MacroInjectTarget) *[]byte {
+	entry, err := f.Open()
+	if err != nil {
+		panic(err)
+	}
+	content, err := ioutil.ReadAll(entry)
+	if err != nil {
+		panic(err)
+	}
+	idx := bytes.Index(content, injectionTarget.Marker)
+	copy(content[idx:idx+len(injectionTarget.Marker)], injectionTarget.Replacement[0:])
+	return &content
+}