Add permissions in profcollectd to parse kernel etm data.

To parse etm data for kernel and kernel modules, add below permissions
to profcollectd:
1. Get kernel start address and module addresses from /proc/kallsyms
and /proc/modules.
2. Get kernel build id from /sys/kernel/notes.
3. Read kernel module files in vendor dir.

Bug: 166559473
Test: run profcollectd.

Change-Id: I2e0b346379271fadc20e720722f7c9a687335ee2

private/domain.te

@@ -498,3 +498,15 @@ neverallow {
   -vendor_init
   -dumpstate
 } mm_events_config_prop:file no_rw_file_perms;
+
+# Allow the tracing daemon and callstack sampler to use kallsyms to symbolize
+# kernel traces. Addresses are not disclosed, they are repalced with symbol
+# names (if available). Traces don't disclose KASLR.
+neverallow {
+  domain
+  -init
+  userdebug_or_eng(`-profcollectd')
+  -vendor_init
+  -traced_probes
+  -traced_perf
+} proc_kallsyms:file { open read };

private/profcollectd.te

@@ -19,6 +19,10 @@ userdebug_or_eng(`
   allow profcollectd system_file_type:file r_file_perms;
   allow profcollectd vendor_file_type:file r_file_perms;
 
+  # Allow profcollectd to search for and read kernel modules.
+  allow profcollectd vendor_file:dir r_dir_perms;
+  allow profcollectd vendor_kernel_modules:file r_file_perms;
+
   # Allow profcollectd to read system bootstrap libs.
   allow profcollectd system_bootstrap_lib_file:dir search;
   allow profcollectd system_bootstrap_lib_file:file r_file_perms;
@@ -45,4 +49,13 @@ userdebug_or_eng(`
   # Allow profcollectd to publish a binder service and make binder calls.
   binder_use(profcollectd)
   add_service(profcollectd, profcollectd_service)
+
+  # Allow to temporarily lift the kptr_restrict setting and get kernel start address
+  # by reading /proc/kallsyms, get module start address by reading /proc/modules.
+  set_prop(profcollectd, lower_kptr_restrict_prop)
+  allow profcollectd proc_kallsyms:file r_file_perms;
+  allow profcollectd proc_modules:file r_file_perms;
+
+  # Allow profcollectd to read kernel build id.
+  allow profcollectd sysfs_kernel_notes:file r_file_perms;
 ')

private/property.te

@@ -533,6 +533,7 @@ neverallow {
 neverallow {
   domain
   -init
+  userdebug_or_eng(`-profcollectd')
   userdebug_or_eng(`-traced_probes')
   userdebug_or_eng(`-traced_perf')
 } {

public/domain.te

@@ -446,17 +446,6 @@ neverallow { domain -init } usermodehelper:file { append write };
 neverallow { domain -init -ueventd } sysfs_usermodehelper:file { append write };
 neverallow { domain -init -vendor_init } proc_security:file { append open read write };
 
-# Allow the tracing daemon and callstack sampler to use kallsyms to symbolize
-# kernel traces. Addresses are not disclosed, they are repalced with symbol
-# names (if available). Traces don't disclose KASLR.
-neverallow {
-  domain
-  -init
-  -vendor_init
-  -traced_probes
-  -traced_perf
-} proc_kallsyms:file { open read };
-
 # Init can't do anything with binder calls. If this neverallow rule is being
 # triggered, it's probably due to a service with no SELinux domain.
 neverallow * init:binder *;