Merge tag 'meminit-v5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull compiler-based variable initialization updates from Kees Cook:
 "This is effectively part of my gcc-plugins tree, but as this adds some
  Clang support, it felt weird to still call it "gcc-plugins". :)

  This consolidates Kconfig for the existing stack variable
  initialization (via structleak and stackleak gcc plugins) and adds
  Alexander Potapenko's support for Clang's new similar functionality.

  Summary:

   - Consolidate memory initialization Kconfigs (Kees)

   - Implement support for Clang's stack variable auto-init (Alexander)"

* tag 'meminit-v5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  security: Implement Clang's stack initialization
  security: Move stackleak config to Kconfig.hardening
  security: Create "kernel hardening" config area

1 files changed, 6 insertions, 120 deletions

diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig
index 74271dba4f94..80220ed26a35 100644
--- a/scripts/gcc-plugins/Kconfig
+++ b/scripts/gcc-plugins/Kconfig
@@ -13,17 +13,19 @@ config HAVE_GCC_PLUGINS
 	  An arch should select this symbol if it supports building with
 	  GCC plugins.
 
-menuconfig GCC_PLUGINS
-	bool "GCC plugins"
+config GCC_PLUGINS
+	bool
 	depends on HAVE_GCC_PLUGINS
 	depends on PLUGIN_HOSTCC != ""
+	default y
 	help
 	  GCC plugins are loadable modules that provide extra features to the
 	  compiler. They are useful for runtime instrumentation and static analysis.
 
 	  See Documentation/gcc-plugins.txt for details.
 
-if GCC_PLUGINS
+menu "GCC plugins"
+	depends on GCC_PLUGINS
 
 config GCC_PLUGIN_CYC_COMPLEXITY
 	bool "Compute the cyclomatic complexity of a function" if EXPERT
@@ -66,71 +68,6 @@ config GCC_PLUGIN_LATENT_ENTROPY
 	   * https://grsecurity.net/
 	   * https://pax.grsecurity.net/
 
-config GCC_PLUGIN_STRUCTLEAK
-	bool "Zero initialize stack variables"
-	help
-	  While the kernel is built with warnings enabled for any missed
-	  stack variable initializations, this warning is silenced for
-	  anything passed by reference to another function, under the
-	  occasionally misguided assumption that the function will do
-	  the initialization. As this regularly leads to exploitable
-	  flaws, this plugin is available to identify and zero-initialize
-	  such variables, depending on the chosen level of coverage.
-
-	  This plugin was originally ported from grsecurity/PaX. More
-	  information at:
-	   * https://grsecurity.net/
-	   * https://pax.grsecurity.net/
-
-choice
-	prompt "Coverage"
-	depends on GCC_PLUGIN_STRUCTLEAK
-	default GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
-	help
-	  This chooses the level of coverage over classes of potentially
-	  uninitialized variables. The selected class will be
-	  zero-initialized before use.
-
-	config GCC_PLUGIN_STRUCTLEAK_USER
-		bool "structs marked for userspace"
-		help
-		  Zero-initialize any structures on the stack containing
-		  a __user attribute. This can prevent some classes of
-		  uninitialized stack variable exploits and information
-		  exposures, like CVE-2013-2141:
-		  https://git.kernel.org/linus/b9e146d8eb3b9eca
-
-	config GCC_PLUGIN_STRUCTLEAK_BYREF
-		bool "structs passed by reference"
-		help
-		  Zero-initialize any structures on the stack that may
-		  be passed by reference and had not already been
-		  explicitly initialized. This can prevent most classes
-		  of uninitialized stack variable exploits and information
-		  exposures, like CVE-2017-1000410:
-		  https://git.kernel.org/linus/06e7e776ca4d3654
-
-	config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
-		bool "anything passed by reference"
-		help
-		  Zero-initialize any stack variables that may be passed
-		  by reference and had not already been explicitly
-		  initialized. This is intended to eliminate all classes
-		  of uninitialized stack variable exploits and information
-		  exposures.
-
-endchoice
-
-config GCC_PLUGIN_STRUCTLEAK_VERBOSE
-	bool "Report forcefully initialized variables"
-	depends on GCC_PLUGIN_STRUCTLEAK
-	depends on !COMPILE_TEST	# too noisy
-	help
-	  This option will cause a warning to be printed each time the
-	  structleak plugin finds a variable it thinks needs to be
-	  initialized. Since not all existing initializers are detected
-	  by the plugin, this can produce false positive warnings.
-
 config GCC_PLUGIN_RANDSTRUCT
 	bool "Randomize layout of sensitive kernel structures"
 	select MODVERSIONS if MODULES
@@ -171,59 +108,8 @@ config GCC_PLUGIN_RANDSTRUCT_PERFORMANCE
 	  in structures.  This reduces the performance hit of RANDSTRUCT
 	  at the cost of weakened randomization.
 
-config GCC_PLUGIN_STACKLEAK
-	bool "Erase the kernel stack before returning from syscalls"
-	depends on GCC_PLUGINS
-	depends on HAVE_ARCH_STACKLEAK
-	help
-	  This option makes the kernel erase the kernel stack before
-	  returning from system calls. That reduces the information which
-	  kernel stack leak bugs can reveal and blocks some uninitialized
-	  stack variable attacks.
-
-	  The tradeoff is the performance impact: on a single CPU system kernel
-	  compilation sees a 1% slowdown, other systems and workloads may vary
-	  and you are advised to test this feature on your expected workload
-	  before deploying it.
-
-	  This plugin was ported from grsecurity/PaX. More information at:
-	   * https://grsecurity.net/
-	   * https://pax.grsecurity.net/
-
-config STACKLEAK_TRACK_MIN_SIZE
-	int "Minimum stack frame size of functions tracked by STACKLEAK"
-	default 100
-	range 0 4096
-	depends on GCC_PLUGIN_STACKLEAK
-	help
-	  The STACKLEAK gcc plugin 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.
-	  If unsure, leave the default value 100.
-
-config STACKLEAK_METRICS
-	bool "Show STACKLEAK metrics in the /proc file system"
-	depends on GCC_PLUGIN_STACKLEAK
-	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
-	  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.
-
-config STACKLEAK_RUNTIME_DISABLE
-	bool "Allow runtime disabling of kernel stack erasing"
-	depends on GCC_PLUGIN_STACKLEAK
-	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 GCC_PLUGIN_ARM_SSP_PER_TASK
 	bool
 	depends on GCC_PLUGINS && ARM
 
-endif
+endmenu