Merge git://git.linaro.org/nico/arm_security into devel-stable (fc4978b7) · Commits · e / devices / android_kernel_fairphone_FP3

arch/arm/Kconfig

+12 −0

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		@@ -1375,6 +1375,18 @@ config UACCESS_WITH_MEMCPY
		However, if the CPU data cache is using a write-allocate mode,
		this option is unlikely to provide any performance gain.

		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.

		endmenu

		menu "Boot options"

+4 −0

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		@@ -34,6 +34,10 @@ 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

+3 −0

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		@@ -121,4 +121,7 @@ int dump_task_regs(struct task_struct t, elf_gregset_t elfregs);
		extern void elf_set_personality(const struct elf32_hdr *);
		#define SET_PERSONALITY(ex) elf_set_personality(&(ex))

		extern unsigned long arch_randomize_brk(struct mm_struct *mm);
		#define arch_randomize_brk arch_randomize_brk

		#endif

0 → 100644

+38 −0

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		/*
		* GCC stack protector support.
		*
		* Stack protector works by putting predefined pattern at the start of
		* the stack frame and verifying that it hasn't been overwritten when
		* returning from the function. The pattern is called stack canary
		* and gcc expects it to be defined by a global variable called
		* "__stack_chk_guard" on ARM. This unfortunately means that on SMP
		* we cannot have a different canary value per task.
		*/

		#ifndef _ASM_STACKPROTECTOR_H
		#define _ASM_STACKPROTECTOR_H 1

		#include <linux/random.h>
		#include <linux/version.h>

		extern unsigned long __stack_chk_guard;

		/*
		* Initialize the stackprotector canary value.
		*
		* NOTE: this must only be called from functions that never return,
		* and it must always be inlined.
		*/
		static __always_inline void boot_init_stack_canary(void)
		{
		unsigned long canary;

		/* Try to get a semi random initial value. */
		get_random_bytes(&canary, sizeof(canary));
		canary ^= LINUX_VERSION_CODE;

		current->stack_canary = canary;
		__stack_chk_guard = current->stack_canary;
		}

		#endif /* _ASM_STACKPROTECTOR_H */

+3 −0

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		@@ -40,6 +40,9 @@
		int main(void)
		{
		DEFINE(TSK_ACTIVE_MM, offsetof(struct task_struct, active_mm));
		#ifdef CONFIG_CC_STACKPROTECTOR
		DEFINE(TSK_STACK_CANARY, offsetof(struct task_struct, stack_canary));
		#endif
		BLANK();
		DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
		DEFINE(TI_PREEMPT, offsetof(struct thread_info, preempt_count));