zh-cn/devices/tech/config/ambient.html - platform/docs/source.android.com - Git at Google

 <html devsite><head>
     <title>实现 Ambient 权能</title>
     <meta name="project_path" value="/_project.yaml"/>
     <meta name="book_path" value="/_book.yaml"/>
   </head>
   <body>
   <!--
       Copyright 2017 The Android Open Source Project

       Licensed under the Apache License, Version 2.0 (the "License");
       you may not use this file except in compliance with the License.
       You may obtain a copy of the License at

           http://www.apache.org/licenses/LICENSE-2.0

       Unless required by applicable law or agreed to in writing, software
       distributed under the License is distributed on an "AS IS" BASIS,
       WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
       See the License for the specific language governing permissions and
       limitations under the License.
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     <p>
 借助此类权能，Linux 进程可以舍弃大多数类似于 root 的权限，同时保留执行其权能所需的权限。此类权能的原始实现使得经过 fork + exec 处理的进程无法继承权能，除非正在执行的文件已配置文件权能。而文件权能会带来安全风险，这是因为任何进程只要执行具有文件权能的文件，则一律会获得这些权能。
     </p>
     <p>
 Ambient 权能允许系统服务在其 <code>.rc</code> 文件中配置各项权能，从而将其所有配置放入单个文件中，而不必将权能配置单独放入 <code>fs_config.c</code> 文件中。
     </p>
     <h2 id="reference-implementation">参考实现</h2>
     <p>
 参考实现是 Android 通用内核 <a href="https://android.googlesource.com/kernel/common/">https://android.googlesource.com/kernel/common/</a>
     </p>
     <h2 id="required-patches">必需的补丁程序</h2>
     <p>
 必需的补丁程序已反向移植到所有相关的 Android 通用内核分支。
     </p>
     <p>
 主要 Ambient 权能补丁程序 <a href="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=58319057b7847667f0c9585b9de0e8932b0fdb08">https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=58319057b7847667f0c9585b9de0e8932b0fdb08</a> 已反向移植到：

 </p>
     <ul>
     <li>android-3.10 分支：
     <ul>
       <li><a href="https://android.googlesource.com/kernel/common/+/bdcd4484f1b399dfcb2fd7dd82b6869b2b6b60cd">https://android.googlesource.com/kernel/common/+/bdcd4484f1b399dfcb2fd7dd82b6869b2b6b60cd</a>
     </li></ul>
     </li><li>android-3.14 分支：
     <ul>
       <li><a href="https://android.googlesource.com/kernel/common/+/5440f16f1296ca05f33dfde51e8bb7ad48699640">https://android.googlesource.com/kernel/common/+/5440f16f1296ca05f33dfde51e8bb7ad48699640</a>
     </li></ul>
     </li><li>android-3.18：
     <ul>
       <li><a href="https://android.googlesource.com/kernel/common/+/d6a9a74487e86b528c44965f871de75671b6adb0">https://android.googlesource.com/kernel/common/+/d6a9a74487e86b528c44965f871de75671b6adb0</a>
     </li></ul>
     </li><li>android-4.1：
     <ul>
       <li><a href="https://android.googlesource.com/kernel/common/+/0381789d78d552462ef576d9759e9aa6fcaae3bb">https://android.googlesource.com/kernel/common/+/0381789d78d552462ef576d9759e9aa6fcaae3bb</a></li>
     </ul>
    </li></ul>

     <p>
 一个小的安全修复程序 <a href="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b7f76ea2ef6739ee484a165ffbac98deb855d3d3">https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b7f76ea2ef6739ee484a165ffbac98deb855d3d3</a> 已反向移植到：</p>

     <ul>
       <li>android-3.10 分支：
     <ul>
         <li><a href="https://android.googlesource.com/kernel/common/+/ef89def080c52eb7ea6a9455eb32b1b05867133b">https://android.googlesource.com/kernel/common/+/ef89def080c52eb7ea6a9455eb32b1b05867133b</a>
       </li></ul>
     </li><li>android-3.14 分支：
     <ul>
       <li><a href="https://android.googlesource.com/kernel/common/+/f75626b3092fad4e0bd8f2aed06947352781eb77">https://android.googlesource.com/kernel/common/+/f75626b3092fad4e0bd8f2aed06947352781eb77</a>
     </li></ul>
     </li><li>android-3.18：
     <ul>
       <li><a href="https://android.googlesource.com/kernel/common/+/7bc0ef844a537ebb786ba0574932bd65751818c6">https://android.googlesource.com/kernel/common/+/7bc0ef844a537ebb786ba0574932bd65751818c6</a>
     </li></ul>
     </li><li>android-4.1：
     <ul>
      <li><a href="https://android.googlesource.com/kernel/common/+/dda568cc40d855bde2dfa9c04a7a1628c80b7f63">https://android.googlesource.com/kernel/common/+/dda568cc40d855bde2dfa9c04a7a1628c80b7f63</a></li>
     </ul>
     </li></ul>

     <p>
 版本低于 3.18 的内核所需的内存泄漏修复程序 <a href="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6d6f3328422a3bc56b0d8dd026a5de845d2abfa7">https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6d6f3328422a3bc56b0d8dd026a5de845d2abfa7</a> 已反向移植到：
 </p>

     <ul>
     <li>android-3.10 分支：
     <ul>
       <li><a href="https://android.googlesource.com/kernel/common/+/900e52782988ee11a1cb7d600e9edea48fc70f0f">https://android.googlesource.com/kernel/common/+/900e52782988ee11a1cb7d600e9edea48fc70f0f</a></li>
     </ul>
   </li></ul>

     <h2 id="validation">验证</h2>
     <p>
     <a href="https://android.googlesource.com/platform/bionic/+/master#Running-the-tests">仿生单元测试</a>包括针对 Ambient 权能的单元测试。此外，如果在 Android init 中为某项服务使用“capabilities”关键字，然后检查该服务是否获得了预期的权能，则可以对 Ambient 权能进行运行时测试。
     </p>

 </body></html>
	<html devsite><head>
	<title>实现 Ambient 权能</title>
	<meta name="project_path" value="/_project.yaml"/>
	<meta name="book_path" value="/_book.yaml"/>
	</head>
	<body>
	<!--
	Copyright 2017 The Android Open Source Project

	Licensed under the Apache License, Version 2.0 (the "License");
	you may not use this file except in compliance with the License.
	You may obtain a copy of the License at

	http://www.apache.org/licenses/LICENSE-2.0

	Unless required by applicable law or agreed to in writing, software
	distributed under the License is distributed on an "AS IS" BASIS,
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	See the License for the specific language governing permissions and
	limitations under the License.
	-->

	<p>
	借助此类权能，Linux 进程可以舍弃大多数类似于 root 的权限，同时保留执行其权能所需的权限。此类权能的原始实现使得经过 fork + exec 处理的进程无法继承权能，除非正在执行的文件已配置文件权能。而文件权能会带来安全风险，这是因为任何进程只要执行具有文件权能的文件，则一律会获得这些权能。
	</p>
	<p>
	Ambient 权能允许系统服务在其 <code>.rc</code> 文件中配置各项权能，从而将其所有配置放入单个文件中，而不必将权能配置单独放入 <code>fs_config.c</code> 文件中。
	</p>
	<h2 id="reference-implementation">参考实现</h2>
	<p>
	参考实现是 Android 通用内核 <a href="https://android.googlesource.com/kernel/common/">https://android.googlesource.com/kernel/common/</a>
	</p>
	<h2 id="required-patches">必需的补丁程序</h2>
	<p>
	必需的补丁程序已反向移植到所有相关的 Android 通用内核分支。
	</p>
	<p>
	主要 Ambient 权能补丁程序 <a href="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=58319057b7847667f0c9585b9de0e8932b0fdb08">https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=58319057b7847667f0c9585b9de0e8932b0fdb08</a> 已反向移植到：

	</p>
	<ul>
	<li>android-3.10 分支：
	<ul>
	<li><a href="https://android.googlesource.com/kernel/common/+/bdcd4484f1b399dfcb2fd7dd82b6869b2b6b60cd">https://android.googlesource.com/kernel/common/+/bdcd4484f1b399dfcb2fd7dd82b6869b2b6b60cd</a>
	</li></ul>
	</li><li>android-3.14 分支：
	<ul>
	<li><a href="https://android.googlesource.com/kernel/common/+/5440f16f1296ca05f33dfde51e8bb7ad48699640">https://android.googlesource.com/kernel/common/+/5440f16f1296ca05f33dfde51e8bb7ad48699640</a>
	</li></ul>
	</li><li>android-3.18：
	<ul>
	<li><a href="https://android.googlesource.com/kernel/common/+/d6a9a74487e86b528c44965f871de75671b6adb0">https://android.googlesource.com/kernel/common/+/d6a9a74487e86b528c44965f871de75671b6adb0</a>
	</li></ul>
	</li><li>android-4.1：
	<ul>
	<li><a href="https://android.googlesource.com/kernel/common/+/0381789d78d552462ef576d9759e9aa6fcaae3bb">https://android.googlesource.com/kernel/common/+/0381789d78d552462ef576d9759e9aa6fcaae3bb</a></li>
	</ul>
	</li></ul>

	<p>
	一个小的安全修复程序 <a href="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b7f76ea2ef6739ee484a165ffbac98deb855d3d3">https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b7f76ea2ef6739ee484a165ffbac98deb855d3d3</a> 已反向移植到：</p>

	<ul>
	<li>android-3.10 分支：
	<ul>
	<li><a href="https://android.googlesource.com/kernel/common/+/ef89def080c52eb7ea6a9455eb32b1b05867133b">https://android.googlesource.com/kernel/common/+/ef89def080c52eb7ea6a9455eb32b1b05867133b</a>
	</li></ul>
	</li><li>android-3.14 分支：
	<ul>
	<li><a href="https://android.googlesource.com/kernel/common/+/f75626b3092fad4e0bd8f2aed06947352781eb77">https://android.googlesource.com/kernel/common/+/f75626b3092fad4e0bd8f2aed06947352781eb77</a>
	</li></ul>
	</li><li>android-3.18：
	<ul>
	<li><a href="https://android.googlesource.com/kernel/common/+/7bc0ef844a537ebb786ba0574932bd65751818c6">https://android.googlesource.com/kernel/common/+/7bc0ef844a537ebb786ba0574932bd65751818c6</a>
	</li></ul>
	</li><li>android-4.1：
	<ul>
	<li><a href="https://android.googlesource.com/kernel/common/+/dda568cc40d855bde2dfa9c04a7a1628c80b7f63">https://android.googlesource.com/kernel/common/+/dda568cc40d855bde2dfa9c04a7a1628c80b7f63</a></li>
	</ul>
	</li></ul>

	<p>
	版本低于 3.18 的内核所需的内存泄漏修复程序 <a href="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6d6f3328422a3bc56b0d8dd026a5de845d2abfa7">https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6d6f3328422a3bc56b0d8dd026a5de845d2abfa7</a> 已反向移植到：
	</p>

	<ul>
	<li>android-3.10 分支：
	<ul>
	<li><a href="https://android.googlesource.com/kernel/common/+/900e52782988ee11a1cb7d600e9edea48fc70f0f">https://android.googlesource.com/kernel/common/+/900e52782988ee11a1cb7d600e9edea48fc70f0f</a></li>
	</ul>
	</li></ul>

	<h2 id="validation">验证</h2>
	<p>
	<a href="https://android.googlesource.com/platform/bionic/+/master#Running-the-tests">仿生单元测试</a>包括针对 Ambient 权能的单元测试。此外，如果在 Android init 中为某项服务使用“capabilities”关键字，然后检查该服务是否获得了预期的权能，则可以对 Ambient 权能进行运行时测试。
	</p>

	</body></html>