misctrl: add a property

misctrl can set properties which can be injected into
bugreports.

Limit visibility of these properties so that no device
code can branch based off these properties.

Bug: 317262681
Test: bugreport
Change-Id: I74f6f240b08b2681540bca262dcc76bcdca9cdad

private/dumpstate.te

@@ -68,6 +68,8 @@ binder_call(dumpstate, ot_daemon)
 # Collect metrics on boot time created by init
 get_prop(dumpstate, boottime_prop)
 
+get_prop(dumpstate, misctrl_prop)
+
 # Signal native processes to dump their stack.
 allow dumpstate {
   mediatranscoding

private/misctrl.te

@@ -8,6 +8,8 @@ allow misctrl misc_block_device:blk_file rw_file_perms;
 allow misctrl block_device:dir r_dir_perms;
 read_fstab(misctrl)
 
+set_prop(misctrl, misctrl_prop)
+
 # bootloader_message tries to find the fstab in the device config path first,
 # but because we've already booted up we can use the ro.boot properties instead,
 # so we can just ignore the SELinux denial.

private/property.te

@@ -35,6 +35,7 @@ system_internal_prop(net_connectivity_prop)
 system_internal_prop(netd_stable_secret_prop)
 system_internal_prop(next_boot_prop)
 system_internal_prop(odsign_prop)
+system_internal_prop(misctrl_prop)
 system_internal_prop(perf_drop_caches_prop)
 system_internal_prop(pm_prop)
 system_internal_prop(profcollectd_node_id_prop)
@@ -185,6 +186,21 @@ neverallow {
   userdebug_or_eng(`-su')
 } init_svc_debug_prop:file no_rw_file_perms;
 
+# DO NOT ADD: compat risk
+neverallow {
+  domain
+  -init
+  -dumpstate
+  -misctrl
+  userdebug_or_eng(`-su')
+} misctrl_prop:file no_rw_file_perms;
+neverallow {
+  domain
+  -init
+  -misctrl
+  userdebug_or_eng(`-su')
+} misctrl_prop:property_service set;
+
 compatible_property_only(`
 # Prevent properties from being set
   neverallow {

private/property_contexts

@@ -98,6 +98,7 @@ ro.boot.btmacaddr       u:object_r:bluetooth_prop:s0
 ro.boot.serialno        u:object_r:serialno_prop:s0
 ro.bt.                  u:object_r:bluetooth_prop:s0
 ro.boot.bootreason      u:object_r:bootloader_boot_reason_prop:s0
+ro.misctrl.             u:object_r:misctrl_prop:s0
 persist.sys.boot.reason u:object_r:last_boot_reason_prop:s0
 sys.boot.reason         u:object_r:system_boot_reason_prop:s0
 sys.boot.reason.last    u:object_r:last_boot_reason_prop:s0