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Commit 19952a92 authored by Kees Cook's avatar Kees Cook Committed by Ingo Molnar
Browse files

stackprotector: Unify the HAVE_CC_STACKPROTECTOR logic between architectures 



Instead of duplicating the CC_STACKPROTECTOR Kconfig and
Makefile logic in each architecture, switch to using
HAVE_CC_STACKPROTECTOR and keep everything in one place. This
retains the x86-specific bug verification scripts.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mips@linux-mips.org
Cc: linux-arch@vger.kernel.org
Link: http://lkml.kernel.org/r/1387481759-14535-2-git-send-email-keescook@chromium.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent b0031f22

Makefile

+11 −3
Original line number Diff line number Diff line
@@ -595,10 +595,18 @@ ifneq ($(CONFIG_FRAME_WARN),0) 
KBUILD_CFLAGS += $(call cc-option,-Wframe-larger-than=${CONFIG_FRAME_WARN})

endif



# Force gcc to behave correct even for buggy distributions

ifndef CONFIG_CC_STACKPROTECTOR

KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector)

# Handle stack protector mode.

ifdef CONFIG_CC_STACKPROTECTOR

  stackp-flag := -fstack-protector

  ifeq ($(call cc-option, $(stackp-flag)),)

    $(warning Cannot use CONFIG_CC_STACKPROTECTOR: \

	      -fstack-protector not supported by compiler))

  endif

else

  # Force off for distro compilers that enable stack protector by default.

  stackp-flag := $(call cc-option, -fno-stack-protector)

endif

KBUILD_CFLAGS += $(stackp-flag)



# This warning generated too much noise in a regular build.

# Use make W=1 to enable this warning (see scripts/Makefile.build)

arch/Kconfig

+22 −0
Original line number Diff line number Diff line
@@ -336,6 +336,28 @@ config SECCOMP_FILTER 


	  See Documentation/prctl/seccomp_filter.txt for details.



config HAVE_CC_STACKPROTECTOR

	bool

	help

	  An arch should select this symbol if:

	  - its compiler supports the -fstack-protector option

	  - it has implemented a stack canary (e.g. __stack_chk_guard)



config CC_STACKPROTECTOR

	bool "Enable -fstack-protector buffer overflow detection"

	depends on HAVE_CC_STACKPROTECTOR

	help

	  This option turns on the -fstack-protector GCC feature. This

	  feature puts, at the beginning of functions, a canary value on

	  the stack just before the return address, and validates

	  the value just before actually returning.  Stack based buffer

	  overflows (that need to overwrite this return address) now also

	  overwrite the canary, which gets detected and the attack is then

	  neutralized via a kernel panic.



	  This feature requires gcc version 4.2 or above, or a distribution

	  gcc with the feature backported.



config HAVE_CONTEXT_TRACKING

	bool

	help

arch/arm/Kconfig

+1 −12
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ config ARM 
	select HAVE_BPF_JIT

	select HAVE_CONTEXT_TRACKING

	select HAVE_C_RECORDMCOUNT

	select HAVE_CC_STACKPROTECTOR

	select HAVE_DEBUG_KMEMLEAK

	select HAVE_DMA_API_DEBUG

	select HAVE_DMA_ATTRS
@@ -1856,18 +1857,6 @@ config SECCOMP 
	  and the task is only allowed to execute a few safe syscalls

	  defined by each seccomp mode.



config CC_STACKPROTECTOR

	bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"

	help

	  This option turns on the -fstack-protector GCC feature. This

	  feature puts, at the beginning of functions, a canary value on

	  the stack just before the return address, and validates

	  the value just before actually returning.  Stack based buffer

	  overflows (that need to overwrite this return address) now also

	  overwrite the canary, which gets detected and the attack is then

	  neutralized via a kernel panic.

	  This feature requires gcc version 4.2 or above.



config SWIOTLB

	def_bool y

arch/arm/Makefile

+0 −4
Original line number Diff line number Diff line
@@ -40,10 +40,6 @@ ifeq ($(CONFIG_FRAME_POINTER),y) 
KBUILD_CFLAGS	+=-fno-omit-frame-pointer -mapcs -mno-sched-prolog

endif



ifeq ($(CONFIG_CC_STACKPROTECTOR),y)

KBUILD_CFLAGS	+=-fstack-protector

endif



ifeq ($(CONFIG_CPU_BIG_ENDIAN),y)

KBUILD_CPPFLAGS	+= -mbig-endian

AS		+= -EB

arch/mips/Kconfig

+1 −13
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ config MIPS 
	select MODULES_USE_ELF_RELA if MODULES && 64BIT

	select CLONE_BACKWARDS

	select HAVE_DEBUG_STACKOVERFLOW

	select HAVE_CC_STACKPROTECTOR



menu "Machine selection"
@@ -2322,19 +2323,6 @@ config SECCOMP 


	  If unsure, say Y. Only embedded should say N here.



config CC_STACKPROTECTOR

	bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"

	help

	  This option turns on the -fstack-protector GCC feature. This

	  feature puts, at the beginning of functions, a canary value on

	  the stack just before the return address, and validates

	  the value just before actually returning.  Stack based buffer

	  overflows (that need to overwrite this return address) now also

	  overwrite the canary, which gets detected and the attack is then

	  neutralized via a kernel panic.



	  This feature requires gcc version 4.2 or above.



config USE_OF

	bool

	select OF