Create unique labels for /dev/snd/{seq,timer}
No core android component needs access to /dev/snd/{seq,timer}, but
currently audioserver, bootanim, init, system_server and ueventd have
access. Seq and timer have been the source of many bugs in the past
[1]. Giving these files new labels without explicitly granting access
removes access from audioserver, bootanim, and system_server.
Init and ueventd still require access for /dev setup.
TODO: Explore unsetting CONFIG_SND_TIMER device kernels.
[1] https://github.com/google/syzkaller/wiki/Found-Bugs
Test: media CTS "cts-tradefed run cts -m CtsMediaTestCases" on Bullhead
and Dragon completed with no denials.
Bug: 29045223
(cherry picked from commit db4510d87a70784ce469f05180956cd057424ae2)
Change-Id: I2d069920e792ce8eef70c7b4a038b9e7000f39f5
diff --git a/file_contexts b/file_contexts
index 41ab949..768af8d 100644
--- a/file_contexts
+++ b/file_contexts
@@ -95,6 +95,8 @@
/dev/rproc_user u:object_r:rpmsg_device:s0
/dev/rtc[0-9] u:object_r:rtc_device:s0
/dev/snd(/.*)? u:object_r:audio_device:s0
+/dev/snd/audio_timer_device u:object_r:audio_timer_device:s0
+/dev/snd/audio_seq_device u:object_r:audio_seq_device:s0
/dev/socket(/.*)? u:object_r:socket_device:s0
/dev/socket/adbd u:object_r:adbd_socket:s0
/dev/socket/sap_uim_socket[0-9] u:object_r:sap_uim_socket:s0