Clarify meaning of untrusted_app and app domain assignment logic.

The current inline documentation is not entirely accurate and caused
user confusion, e.g. see:
https://groups.google.com/d/msg/android-security-discuss/javBrPT8ius/C4EVEFUu4ZoJ

Try to clarify the meaning of untrusted_app, how app domains are
assigned, and how to move other system apps out of untrusted_app into
a different domain.

Change-Id: I98d344dd078fe9e2738b68636adaabda1f4b3c3a
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
This commit is contained in:
Stephen Smalley 2014-02-21 13:26:20 -05:00
parent b73d321ad0
commit d823f83e54

View File

@ -1,9 +1,20 @@
###
### Untrusted apps.
###
### This file defines the rules for untrusted apps. An "untrusted
### app" is an APP with UID between APP_AID (10000)
### and AID_ISOLATED_START (99000).
### This file defines the rules for untrusted apps.
### Apps are labeled based on mac_permissions.xml (maps signer and
### optionally package name to seinfo value) and seapp_contexts (maps UID
### and optionally seinfo value to domain for process and type for data
### directory). The untrusted_app domain is the default assignment in
### seapp_contexts for any app with UID between APP_AID (10000)
### and AID_ISOLATED_START (99000) if the app has no specific seinfo
### value as determined from mac_permissions.xml. In current AOSP, this
### domain is assigned to all non-system apps as well as to any system apps
### that are not signed by one of the four platform keys. To move
### a system app into a specific domain, add a signer entry for it to
### mac_permissions.xml and assign it one of the pre-existing seinfo values
### or define and use a new seinfo value in both mac_permissions.xml and
### seapp_contexts.
###
### untrusted_app includes all the appdomain rules, plus the
### additional following rules: