Void-Hardened-Kernel/0004.patch

diff -rcNP og/Documentation/admin-guide/sysctl/kernel.rst new/Documentation/admin-guide/sysctl/kernel.rst
*** og/Documentation/admin-guide/sysctl/kernel.rst	2022-01-23 17:06:11.000000000 +0200
--- new/Documentation/admin-guide/sysctl/kernel.rst	2022-01-23 17:04:03.000000000 +0200
***************
*** 743,750 ****
  perf_event_paranoid:
  ====================

! Controls use of the performance events system by unprivileged
! users (without CAP_SYS_ADMIN).  The default value is 2.

  ===  ==================================================================
   -1  Allow use of (almost) all events by all users
--- 743,750 ----
  perf_event_paranoid:
  ====================

! Controls use of the performance events system by
! users.  The default value is 2.

  ===  ==================================================================
   -1  Allow use of (almost) all events by all users
***************
*** 759,765 ****

  >=2  Disallow kernel profiling by users without CAP_SYS_ADMIN

! >=3  Disallow use of any event by users without CAP_SYS_ADMIN
  ===  ==================================================================


--- 759,767 ----

  >=2  Disallow kernel profiling by users without CAP_SYS_ADMIN

! >=3  Disallow all unprivileged perf event use
!
! >=69  Disallow all perf event use by everyone, including root
  ===  ==================================================================


diff -rcNP og/include/linux/perf_event.h new/include/linux/perf_event.h
*** og/include/linux/perf_event.h	2022-01-23 17:06:04.000000000 +0200
--- new/include/linux/perf_event.h	2022-01-23 17:00:53.000000000 +0200
***************
*** 1257,1262 ****
--- 1257,1267 ----
  	return sysctl_perf_event_paranoid > 2;
  }

+ static inline bool perf_paranoid_all(void)
+ {
+ 	return sysctl_perf_event_paranoid = 69;
+ }
+
  static inline bool perf_paranoid_tracepoint_raw(void)
  {
  	return sysctl_perf_event_paranoid > -1;
diff -rcNP og/kernel/events/core.c new/kernel/events/core.c
*** og/kernel/events/core.c	2022-01-23 17:06:05.000000000 +0200
--- new/kernel/events/core.c	2022-01-23 17:00:53.000000000 +0200
***************
*** 405,410 ****
--- 405,411 ----
   *   1 - disallow cpu events for unpriv
   *   2 - disallow kernel profiling for unpriv
   *   3 - disallow all unpriv perf event use
+  *   69 - disallow all perf event use
   */
  #ifdef CONFIG_SECURITY_PERF_EVENTS_RESTRICT
  int sysctl_perf_event_paranoid __read_mostly = 3;
***************
*** 10940,10945 ****
--- 10941,10949 ----
  	if (flags & ~PERF_FLAG_ALL)
  		return -EINVAL;

+ 	if (perf_paranoid_all())
+ 		return -EACCES;
+
  	if (perf_paranoid_any() && !capable(CAP_SYS_ADMIN))
  		return -EACCES;