android10/system/sepolicy/private/mac_permissions.xml

<?xml version="1.0" encoding="utf-8"?>
<policy>

<!--

    * A signature is a hex encoded X.509 certificate or a tag defined in
      keys.conf and is required for each signer tag. The signature can
      either appear as a set of attached cert child tags or as an attribute.
    * A signer tag must contain a seinfo tag XOR multiple package stanzas.
    * Each signer/package tag is allowed to contain one seinfo tag. This tag
      represents additional info that each app can use in setting a SELinux security
      context on the eventual process as well as the apps data directory.
    * seinfo assignments are made according to the following rules:
      - Stanzas with package name refinements will be checked first.
      - Stanzas w/o package name refinements will be checked second.
      - The "default" seinfo label is automatically applied.

    * valid stanzas can take one of the following forms:

     // single cert protecting seinfo
     <signer signature="@PLATFORM" >
       <seinfo value="platform" />
     </signer>

     // multiple certs protecting seinfo (all contained certs must match)
     <signer>
       <cert signature="@PLATFORM1"/>
       <cert signature="@PLATFORM2"/>
       <seinfo value="platform" />
     </signer>

     // single cert protecting explicitly named app
     <signer signature="@PLATFORM" >
       <package name="com.android.foo">
         <seinfo value="bar" />
       </package>
     </signer>

     // multiple certs protecting explicitly named app (all certs must match)
     <signer>
       <cert signature="@PLATFORM1"/>
       <cert signature="@PLATFORM2"/>
       <package name="com.android.foo">
         <seinfo value="bar" />
       </package>
     </signer>
-->

    <!-- Platform dev key in AOSP -->
    <signer signature="@PLATFORM" >
      <seinfo value="platform" />
    </signer>

    <!-- Media key in AOSP -->
    <signer signature="@MEDIA" >
      <seinfo value="media" />
    </signer>

    <signer signature="@NETWORK_STACK" >
      <seinfo value="network_stack" />
    </signer>
</policy>