untrusted_app: confine filesystem creation to sandbox
untrusted_apps could be allowed to create/unlink files in world
accessible /data locations. These applications could create
files in a way that would need cap dac_override to remove from
the system when they are uninstalled and/or leave orphaned
data behind.
Keep untrusted_app file creation to sandbox, sdcard and media
locations.
Change-Id: Ife680cb9425dad8223651f16b9be8a3179839ec3
Signed-off-by: William Roberts <william.c.roberts@intel.com>
diff --git a/untrusted_app.te b/untrusted_app.te
index a92323e..1b2d89e 100644
--- a/untrusted_app.te
+++ b/untrusted_app.te
@@ -148,3 +148,21 @@
# Do not allow untrusted_app to set system properties.
neverallow untrusted_app property_socket:sock_file write;
neverallow untrusted_app property_type:property_service set;
+
+# Do not allow untrusted_app to create/unlink files outside of its sandbox,
+# internal storage or sdcard.
+# World accessible data locations allow application to fill the device
+# with unaccounted for data. This data will not get removed during
+# application un-installation.
+neverallow untrusted_app {
+ fs_type
+ -fuse # sdcard
+ file_type
+ -app_data_file # The apps sandbox itself
+ -media_rw_data_file # Internal storage. Known that apps can
+ # leave artfacts here after uninstall.
+ userdebug_or_eng(`
+ -method_trace_data_file # only on ro.debuggable=1
+ -coredump_file # userdebug/eng only
+ ')
+}:dir_file_class_set { create unlink };