Add inject.sh and permanent injection docs

README.md

@@ -20,10 +20,20 @@ Output: `MasterPDFEditor.dylib`
 
 ## Usage
 
+To use the dylib, you have two options:
+
+**Option 1 — DYLD_INSERT_LIBRARIES** (requires SIP to be turned off; refer to [Apple's documentation](https://developer.apple.com/documentation/security/disabling-and-enabling-system-integrity-protection)):
+
 ```sh
 DYLD_INSERT_LIBRARIES=/path/to/MasterPDFEditor.dylib '/Applications/Master PDF Editor.app/Contents/MacOS/Master PDF Editor'
 ```
 
+**Option 2 — Permanent injection** (uses [optool](https://github.com/alexzielenski/optool) to inject the dylib into the app bundle):
+
+```sh
+./inject.sh /path/to/MasterPDFEditor.dylib '/Applications/Master PDF Editor.app'
+```
+
 ## Analysis
 
 Full reverse engineering write-up: [noham.dev](https://noh.am/en/posts/master-pdf-editor-patch-analysis/)

inject.sh

@@ -0,0 +1,74 @@
+#!/bin/bash
+
+set -e  # Exit immediately if a command exits with a non-zero status
+
+# Function to display usage instructions
+usage() {
+    echo "Usage: $0 <dylib> <app_path>"
+    echo "  dylib      - The dynamic library to inject."
+    echo "  app_path   - The path to the .app bundle."
+    exit 1
+}
+
+# Ensure required arguments are provided
+if [ "$#" -ne 2 ]; then
+    echo "[ERROR] Incorrect number of arguments."
+    usage
+fi
+
+DYLIB=$1
+APP_PATH=$2
+
+# Validate inputs
+if [ ! -f "$DYLIB" ]; then
+    echo "[ERROR] The specified dynamic library ($DYLIB) does not exist."
+    exit 1
+fi
+
+if [ ! -d "$APP_PATH" ]; then
+    echo "[ERROR] The specified app path ($APP_PATH) does not exist."
+    exit 1
+fi
+
+INFO_PLIST_PATH="$APP_PATH/Contents/Info.plist"
+if [ ! -f "$INFO_PLIST_PATH" ]; then
+    echo "[ERROR] Info.plist not found at $INFO_PLIST_PATH"
+    exit 1
+fi
+
+# Get the executable name from Info.plist
+APP_NAME=$(/usr/libexec/PlistBuddy -c "Print CFBundleExecutable" "$INFO_PLIST_PATH")
+if [ -z "$APP_NAME" ]; then
+    echo "[ERROR] Could not read CFBundleExecutable from $INFO_PLIST_PATH"
+    exit 1
+fi
+
+echo "[INFO] Executable name: $APP_NAME"
+
+EXECUTABLE_PATH="$APP_PATH/Contents/MacOS/$APP_NAME"
+if [ ! -f "$EXECUTABLE_PATH" ]; then
+    echo "[ERROR] The specified executable ($EXECUTABLE_PATH) does not exist."
+    exit 1
+fi
+
+# Ensure Resources folder exists
+mkdir -p "$APP_PATH/Contents/Resources/"
+
+# Copy the dylib to the Resources folder
+cp "$DYLIB" "$APP_PATH/Contents/Resources/"
+echo "[INFO] Copied $DYLIB to $APP_PATH/Contents/Resources/"
+
+# # Remove existing code signature
+# codesign --remove-signature "$EXECUTABLE_PATH"
+# echo "[INFO] Removed existing code signature from $EXECUTABLE_PATH"
+
+# Inject the dylib using optool
+optool install -c load -p "@executable_path/../Resources/$(basename "$DYLIB")" -t "$EXECUTABLE_PATH"
+echo "[INFO] Injected $DYLIB into $EXECUTABLE_PATH"
+
+# Re-sign the application
+sudo codesign -f -s - --timestamp=none --all-architectures --deep "$APP_PATH"
+sudo xattr -cr "$APP_PATH"
+echo "[INFO] Re-signed $APP_PATH"
+
+exit 0