llkd: Add stack symbol checking

llkd needs the ptrace capabilities and dac override to monitor for
live lock conditions on the stack dumps.

Test: compile
Bug: 33808187
Change-Id: Ibc1e4cc10395fa9685c4ef0ca214daf212a5e126
diff --git a/private/compat/26.0/26.0.ignore.cil b/private/compat/26.0/26.0.ignore.cil
index fb8cde1..41979af 100644
--- a/private/compat/26.0/26.0.ignore.cil
+++ b/private/compat/26.0/26.0.ignore.cil
@@ -76,10 +76,11 @@
     incident_helper
     incident_helper_exec
     kmsg_debug_device
+    last_boot_reason_prop
     llkd
     llkd_exec
+    llkd_prop
     llkd_tmpfs
-    last_boot_reason_prop
     lowpan_device
     lowpan_prop
     lowpan_service
diff --git a/private/compat/27.0/27.0.ignore.cil b/private/compat/27.0/27.0.ignore.cil
index 4e95303..278d605 100644
--- a/private/compat/27.0/27.0.ignore.cil
+++ b/private/compat/27.0/27.0.ignore.cil
@@ -69,6 +69,7 @@
     last_boot_reason_prop
     llkd
     llkd_exec
+    llkd_prop
     llkd_tmpfs
     lowpan_device
     lowpan_prop
diff --git a/private/compat/28.0/28.0.ignore.cil b/private/compat/28.0/28.0.ignore.cil
index c64e341..6a79c75 100644
--- a/private/compat/28.0/28.0.ignore.cil
+++ b/private/compat/28.0/28.0.ignore.cil
@@ -14,6 +14,7 @@
     hal_system_suspend_default_tmpfs
     llkd
     llkd_exec
+    llkd_prop
     llkd_tmpfs
     mnt_product_file
     overlayfs_file
diff --git a/private/crash_dump.te b/private/crash_dump.te
index a50740e..aabff29 100644
--- a/private/crash_dump.te
+++ b/private/crash_dump.te
@@ -7,17 +7,23 @@
   -init
   -kernel
   -keystore
+  -llkd
   -logd
   -ueventd
   -vendor_init
   -vold
 }:process { ptrace signal sigchld sigstop sigkill };
+userdebug_or_eng(`
+  allow crash_dump { llkd logd }:process { ptrace signal sigchld sigstop sigkill };
+')
 
 neverallow crash_dump {
   bpfloader
   init
   kernel
   keystore
+  llkd
+  userdebug_or_eng(`-llkd')
   logd
   userdebug_or_eng(`-logd')
   ueventd
diff --git a/private/domain.te b/private/domain.te
index 1ae31ae..5c6fec8 100644
--- a/private/domain.te
+++ b/private/domain.te
@@ -8,6 +8,7 @@
 neverallow {
   domain
   -vold
+  userdebug_or_eng(`-llkd')
   -dumpstate
   userdebug_or_eng(`-incidentd')
   -storaged
diff --git a/private/llkd.te b/private/llkd.te
index 54c6d04..73e3f58 100644
--- a/private/llkd.te
+++ b/private/llkd.te
@@ -3,7 +3,13 @@
 
 init_daemon_domain(llkd)
 
+get_prop(llkd, llkd_prop)
+
 allow llkd self:global_capability_class_set kill;
+userdebug_or_eng(`
+  allow llkd self:global_capability_class_set sys_ptrace;
+  allow llkd self:global_capability_class_set dac_override;
+')
 
 # llkd optionally locks itself in memory, to prevent it from being
 # swapped out and unable to discover a kernel in live-lock state.
@@ -12,6 +18,16 @@
 # Send kill signals to _anyone_ suffering from Live Lock
 allow llkd domain:process sigkill;
 
+# read stack to check for Live Lock
+userdebug_or_eng(`
+  allow llkd {
+    domain
+    -keystore
+    -init
+    -llkd
+  }:process ptrace;
+')
+
 # live lock watchdog process allowed to look through /proc/
 allow llkd domain:dir r_dir_perms;
 allow llkd domain:file r_file_perms;
@@ -27,6 +43,7 @@
 ### neverallow rules
 
 neverallow { domain -init } llkd:process { dyntransition transition };
+neverallow { domain userdebug_or_eng(`-crash_dump') } llkd:process ptrace;
 
 # never honor LD_PRELOAD
 neverallow * llkd:process noatsecure;
diff --git a/private/property_contexts b/private/property_contexts
index 2726d84..b0f8653 100644
--- a/private/property_contexts
+++ b/private/property_contexts
@@ -34,6 +34,10 @@
 debug.db.               u:object_r:debuggerd_prop:s0
 dumpstate.              u:object_r:dumpstate_prop:s0
 dumpstate.options       u:object_r:dumpstate_options_prop:s0
+llk.                    u:object_r:llkd_prop:s0
+khungtask.              u:object_r:llkd_prop:s0
+ro.llk.                 u:object_r:llkd_prop:s0
+ro.khungtask.           u:object_r:llkd_prop:s0
 log.                    u:object_r:log_prop:s0
 log.tag                 u:object_r:log_tag_prop:s0
 log.tag.WifiHAL         u:object_r:wifi_log_prop:s0