Android8.1Apk调用系统灰名单的lib库时警告信息

楼主^#

更多发布于：2020-05-13 17:20

客户的Apk中link了系统灰名单中的lib库，在Android7.1 中没有任何提示。但是在Android8.1中会有Toast提示：
unauthorized access to libxxx之类的。

logcat也有这样类似的打印:

04-30 02:37:14.956 2591 2591 W linker : library "libstagefright.so" ("/system/lib/libstagefright.so") needed or dlopened by "/data/app/air.com.joystudy.subsix-tAB-mk_Cnd4Kg4l1f6Icsg==/lib/arm/libCore.so" is not accessible for the namespace "classloader-namespace" - the access is temporarily granted as a workaround for http://b/26394120, note that the access will be removed in future releases of Android.
04-30 02:37:14.957 2591 2591 W linker : library "libutils.so" ("/system/lib/libutils.so") needed or dlopened by "/data/app/air.com.joystudy.subsix-tAB-mk_Cnd4Kg4l1f6Icsg==/lib/arm/libCore.so" is not accessible for the namespace "classloader-namespace" - the access is temporarily granted as a workaround for http://b/26394120, note that the access will be removed in future releases of Android.
04-30 02:37:14.957 2591 2591 W linker : library "libui.so" ("/system/lib/libui.so") needed or dlopened by "/data/app/air.com.joystudy.subsix-tAB-mk_Cnd4Kg4l1f6Icsg==/lib/arm/libCore.so" is not accessible for the namespace "classloader-namespace" - the access is temporarily granted as a workaround for http://b/26394120, note that the access will be removed in future releases of Android.

看这个打印日志是警告，意思是现在你们还可以暂时使用灰名单中的系统lib库，限期整改，以后的安卓版本中就会删除灰名单，你们就彻底不能用这些系统lib库，直接崩溃报错？
看了一下打印信息是在源码的 bionic/linker/linker.cpp中
这里是灰名单：

// TODO(dimitry): The grey-list is a workaround for http://b/26394120 ---
// gradually remove libraries from this list until it is gone.
static bool is_greylisted(const char* name, const soinfo* needed_by) {
  static const char* const kLibraryGreyList[] = {
   "libandroid_runtime.so",
   "libbinder.so",
   "libcrypto.so",
   "libcutils.so",
   "libexpat.so",
   "libgui.so",
   "libmedia.so",
   "libnativehelper.so",
   "libskia.so",
   "libssl.so",
   "libstagefright.so",
   "libsqlite.so",
   "libui.so",
   "libutils.so",
   "libvorbisidec.so",
   nullptr
  };

这里是警告日志Toast提示的地方：

if (!ns->is_accessible(realpath)) {
   // TODO(dimitry): workaround for http://b/26394120 - the grey-list
   const soinfo* needed_by = task->is_dt_needed() ? task->get_needed_by() : nullptr;
   if (is_greylisted(name, needed_by)) {
   // print warning only if needed by non-system library
   if (needed_by == nullptr || !is_system_library(needed_by->get_realpath())) {
   const soinfo* needed_or_dlopened_by = task->get_needed_by();
   const char* sopath = needed_or_dlopened_by == nullptr ? "(unknown)" :
   needed_or_dlopened_by->get_realpath();
   DL_WARN("library \"%s\" (\"%s\") needed or dlopened by \"%s\" is not accessible for the namespace \"%s\""
   " - the access is temporarily granted as a workaround for http://b/26394120, note that the access"
   " will be removed in future releases of Android.",
   name, realpath.c_str(), sopath, ns->get_name());
   add_dlwarning(sopath, "unauthorized access to", name);
   }
   } else {
   // do not load libraries if they are not accessible for the specified namespace.
   const char* needed_or_dlopened_by = task->get_needed_by() == nullptr ?