Initial sepolicy for app_zygote.
The application zygote is a new sort of zygote process that is a
child of the regular zygote. Each application zygote is tied to the
application for which it's launched. Once it's started, it will
pre-load some of the code for that specific application, much like
the regular zygote does for framework code.
Once the application zygote is up and running, it can spawn
isolated service processes that run in the isolated_app domain. These
services can then benefit from already having the relevant
application code and data pre-loaded.
The policy is largely the same as the webview_zygote domain,
however there are a few crucial points where the policy is different.
1) The app_zygote runs under the UID of the application that spawned
it.
2) During app_zygote launch, it will call a callback that is
controlled by the application, that allows the application to
pre-load code and data that it thinks is relevant.
Especially point 2 is imporant: it means that untrusted code can run
in the app_zygote context. This context is severely limited, and the
main concern is around the setgid/setuid capabilities. Those conerns
are mitigated by installing a seccomp filter that only allows
setgid/setuid to be called in a safe range.
Bug: 111434506
Test: app_zygote can start and fork children without denials.
Change-Id: I1cc49ee0042d41e5ac6eb81d8f8a10ba448d4832
diff --git a/private/isolated_app.te b/private/isolated_app.te
index 3759488..3443dc4 100644
--- a/private/isolated_app.te
+++ b/private/isolated_app.te
@@ -43,6 +43,13 @@
# Read system properties managed by webview_zygote.
allow isolated_app webview_zygote_tmpfs:file read;
+# Inherit FDs from the app_zygote.
+allow isolated_app app_zygote:fd use;
+# Notify app_zygote of child death.
+allow isolated_app app_zygote:process sigchld;
+# Inherit logd write socket.
+allow isolated_app app_zygote:unix_dgram_socket write;
+
# TODO (b/63631799) fix this access
# suppress denials to /data/local/tmp
dontaudit isolated_app shell_data_file:dir search;