Allow callers of uevent_kernel_*() access to /proc/sys/kernel/overflowuid

Bug: 62378620
Test: Android in Chrome OS can call uevent_kernel_recv() and not fail
      with EIO.
Test: bullhead networking still works

Change-Id: I4dd5d2148ee1704c4fa23d7fd82d1ade19b58cbd
diff --git a/private/compat/26.0/26.0.cil b/private/compat/26.0/26.0.cil
index 4ebb66e..1ebab61 100644
--- a/private/compat/26.0/26.0.cil
+++ b/private/compat/26.0/26.0.cil
@@ -455,6 +455,7 @@
     proc_kmsg
     proc_loadavg
     proc_mounts
+    proc_overflowuid
     proc_page_cluster
     proc_pagetypeinfo
     proc_random
diff --git a/private/genfs_contexts b/private/genfs_contexts
index a6de59a..ee17d49 100644
--- a/private/genfs_contexts
+++ b/private/genfs_contexts
@@ -31,6 +31,7 @@
 genfscon proc /sys/kernel/kptr_restrict u:object_r:proc_security:s0
 genfscon proc /sys/kernel/modprobe u:object_r:usermodehelper:s0
 genfscon proc /sys/kernel/modules_disabled u:object_r:proc_security:s0
+genfscon proc /sys/kernel/overflowuid u:object_r:proc_overflowuid:s0
 genfscon proc /sys/kernel/perf_event_max_sample_rate u:object_r:proc_perf:s0
 genfscon proc /sys/kernel/poweroff_cmd u:object_r:usermodehelper:s0
 genfscon proc /sys/kernel/random u:object_r:proc_random:s0