Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 67688789 authored by Janis Danisevskis's avatar Janis Danisevskis
Browse files

Document restricted app private file permissions 

Make the docs reflect changes in private file access permissions.

Starting with API level 24 app private files are exclusively accessible
to the owning app. Files can no longer be shared by name because apps
cannot relax the files system permissions.

Bug: 27636012
Change-Id: I0139b82547c6f6bede2503aa06b5d2a34cad5a49
parent 0bee3d29

docs/html/preview/behavior-changes.jd

+50 −1
Original line number Diff line number Diff line
@@ -18,7 +18,11 @@ page.image=images/cards/card-n-changes_2x.png 
      <li><a href="#bg-opt">Background Optimizations</a></li>

    </ol>

  </li>

  <li><a href="#perm">Permissions Changes</a></li>

  <li><a href="#perm">Permissions Changes</a>

    <ol>

      <li><a href="#permfilesys">File System Permission Changes</a></li>

    </ol>

  </li>

  <li><a href="#accessibility">Accessibility Improvements</a>

    <ol>

      <li><a href="#screen-zoom">Screen Zoom</a></li>
@@ -200,7 +204,52 @@ page.image=images/cards/card-n-changes_2x.png 


</ul>



<h3 id="permfilesys">File system permission changes</h3>



<p>

  In order to improve the security of private files, the private directory of

  apps targeting Android N or higher has restricted access (0700). This prevents

  leakage of metadata of private files, such as their size or existence. This

  has multiple side effects:

</p>



<ul>

  <li>

    Private files’ file permissions can no longer be relaxed by the owner, and

    an attempt to do so using

    {@link android.content.Context#MODE_WORLD_READABLE} and/or

    {@link android.content.Context#MODE_WORLD_WRITEABLE}, will trigger a

    {@link java.lang.SecurityException}.

  </li>

  <li>

    Passing <code>file://</code> URIs outside the package domain may leave the

    receiver with an unaccessible path. Therefore, attempts to pass a

    <code>file://</code> URI trigger a

    <code>FileUriExposedException</code>. The recommended way to share the

    content of a private file is using the {@link

    android.support.v4.content.FileProvider}.

  </li>

  <li>

    The {@link android.app.DownloadManager} can no longer share privately

    stored files by filename. Legacy applications may end up with an

    unaccessible path when accessing {@link

    android.app.DownloadManager#COLUMN_LOCAL_FILENAME}. Apps targeting

    Android N or higher trigger a {@link java.lang.SecurityException} when

    attempting to access

    {@link android.app.DownloadManager#COLUMN_LOCAL_FILENAME}.

    Legacy applications that set the download location to a public location by

    using

    {@link

    android.app.DownloadManager.Request#setDestinationInExternalFilesDir} or

    {@link

    android.app.DownloadManager.Request#setDestinationInExternalPublicDir}

    can still access the path in

    {@link android.app.DownloadManager#COLUMN_LOCAL_FILENAME}, however, this

    method is strongly discouraged. The preferred way of accessing a file

    exposed by the {@link android.app.DownloadManager} is using

    {@link android.content.ContentResolver#openFileDescriptor}.

  </li>

</ul>



<h2 id="accessibility">Accessibility Improvements</h2>