Merge tag 'hardening-v6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull hardening updates from Kees Cook:

 - Introduce and start using TRAILING_OVERLAP() helper for fixing
   embedded flex array instances (Gustavo A. R. Silva)

 - mux: Convert mux_control_ops to a flex array member in mux_chip
   (Thorsten Blum)

 - string: Group str_has_prefix() and strstarts() (Andy Shevchenko)

 - Remove KCOV instrumentation from __init and __head (Ritesh Harjani,
   Kees Cook)

 - Refactor and rename stackleak feature to support Clang

 - Add KUnit test for seq_buf API

 - Fix KUnit fortify test under LTO

* tag 'hardening-v6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (22 commits)
  sched/task_stack: Add missing const qualifier to end_of_stack()
  kstack_erase: Support Clang stack depth tracking
  kstack_erase: Add -mgeneral-regs-only to silence Clang warnings
  init.h: Disable sanitizer coverage for __init and __head
  kstack_erase: Disable kstack_erase for all of arm compressed boot code
  x86: Handle KCOV __init vs inline mismatches
  arm64: Handle KCOV __init vs inline mismatches
  s390: Handle KCOV __init vs inline mismatches
  arm: Handle KCOV __init vs inline mismatches
  mips: Handle KCOV __init vs inline mismatch
  powerpc/mm/book3s64: Move kfence and debug_pagealloc related calls to __init section
  configs/hardening: Enable CONFIG_INIT_ON_FREE_DEFAULT_ON
  configs/hardening: Enable CONFIG_KSTACK_ERASE
  stackleak: Split KSTACK_ERASE_CFLAGS from GCC_PLUGINS_CFLAGS
  stackleak: Rename stackleak_track_stack to __sanitizer_cov_stack_depth
  stackleak: Rename STACKLEAK to KSTACK_ERASE
  seq_buf: Introduce KUnit tests
  string: Group str_has_prefix() and strstarts()
  kunit/fortify: Add back "volatile" for sizeof() constants
  acpi: nfit: intel: avoid multiple -Wflex-array-member-not-at-end warnings
  ...

1 files changed, 26 insertions, 19 deletions

diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening
index fd1238753cad..b9a5bc3430aa 100644
--- a/security/Kconfig.hardening
+++ b/security/Kconfig.hardening
@@ -82,10 +82,13 @@ choice
 
 endchoice
 
-config GCC_PLUGIN_STACKLEAK
+config CC_HAS_SANCOV_STACK_DEPTH_CALLBACK
+	def_bool $(cc-option,-fsanitize-coverage-stack-depth-callback-min=1)
+
+config KSTACK_ERASE
 	bool "Poison kernel stack before returning from syscalls"
-	depends on GCC_PLUGINS
-	depends on HAVE_ARCH_STACKLEAK
+	depends on HAVE_ARCH_KSTACK_ERASE
+	depends on GCC_PLUGINS || CC_HAS_SANCOV_STACK_DEPTH_CALLBACK
 	help
 	  This option makes the kernel erase the kernel stack before
 	  returning from system calls. This has the effect of leaving
@@ -103,6 +106,10 @@ config GCC_PLUGIN_STACKLEAK
 	  are advised to test this feature on your expected workload before
 	  deploying it.
 
+config GCC_PLUGIN_STACKLEAK
+	def_bool KSTACK_ERASE
+	depends on GCC_PLUGINS
+	help
 	  This plugin was ported from grsecurity/PaX. More information at:
 	   * https://grsecurity.net/
 	   * https://pax.grsecurity.net/
@@ -117,37 +124,37 @@ config GCC_PLUGIN_STACKLEAK_VERBOSE
 	  instrumented. This is useful for comparing coverage between
 	  builds.
 
-config STACKLEAK_TRACK_MIN_SIZE
-	int "Minimum stack frame size of functions tracked by STACKLEAK"
+config KSTACK_ERASE_TRACK_MIN_SIZE
+	int "Minimum stack frame size of functions tracked by KSTACK_ERASE"
 	default 100
 	range 0 4096
-	depends on GCC_PLUGIN_STACKLEAK
+	depends on KSTACK_ERASE
 	help
-	  The STACKLEAK gcc plugin instruments the kernel code for tracking
+	  The KSTACK_ERASE option instruments the kernel code for tracking
 	  the lowest border of the kernel stack (and for some other purposes).
-	  It inserts the stackleak_track_stack() call for the functions with
-	  a stack frame size greater than or equal to this parameter.
+	  It inserts the __sanitizer_cov_stack_depth() call for the functions
+	  with a stack frame size greater than or equal to this parameter.
 	  If unsure, leave the default value 100.
 
-config STACKLEAK_METRICS
-	bool "Show STACKLEAK metrics in the /proc file system"
-	depends on GCC_PLUGIN_STACKLEAK
+config KSTACK_ERASE_METRICS
+	bool "Show KSTACK_ERASE metrics in the /proc file system"
+	depends on KSTACK_ERASE
 	depends on PROC_FS
 	help
-	  If this is set, STACKLEAK metrics for every task are available in
-	  the /proc file system. In particular, /proc/<pid>/stack_depth
+	  If this is set, KSTACK_ERASE metrics for every task are available
+	  in the /proc file system. In particular, /proc/<pid>/stack_depth
 	  shows the maximum kernel stack consumption for the current and
 	  previous syscalls. Although this information is not precise, it
-	  can be useful for estimating the STACKLEAK performance impact for
-	  your workloads.
+	  can be useful for estimating the KSTACK_ERASE performance impact
+	  for your workloads.
 
-config STACKLEAK_RUNTIME_DISABLE
+config KSTACK_ERASE_RUNTIME_DISABLE
 	bool "Allow runtime disabling of kernel stack erasing"
-	depends on GCC_PLUGIN_STACKLEAK
+	depends on KSTACK_ERASE
 	help
 	  This option provides 'stack_erasing' sysctl, which can be used in
 	  runtime to control kernel stack erasing for kernels built with
-	  CONFIG_GCC_PLUGIN_STACKLEAK.
+	  CONFIG_KSTACK_ERASE.
 
 config INIT_ON_ALLOC_DEFAULT_ON
 	bool "Enable heap memory zeroing on allocation by default"