Fix rapid7#7703, mark osx-app macho as executable

Author: timwr

lib/msf/util/exe.rb

@@ -887,9 +887,10 @@ def self.to_osx_app(exe, opts = {})
     zip = Rex::Zip::Archive.new
     zip.add_file("#{app_name}/", '')
     zip.add_file("#{app_name}/Contents/", '')
-    zip.add_file("#{app_name}/Contents/MacOS/", '')
     zip.add_file("#{app_name}/Contents/Resources/", '')
-    zip.add_file("#{app_name}/Contents/MacOS/#{exe_name}", exe)
+    zip.add_file("#{app_name}/Contents/MacOS/", '')
+    # Add the macho and mark it as executable
+    zip.add_file("#{app_name}/Contents/MacOS/#{exe_name}", exe).last.attrs = 0x10
     zip.add_file("#{app_name}/Contents/Info.plist", info_plist)
     zip.add_file("#{app_name}/Contents/PkgInfo", 'APPLaplt')
     zip.pack