From c0c264ae5112d1cdb7d37d4e208b7a7e766a7418 Mon Sep 17 00:00:00 2001 From: Laura Abbott Date: Wed, 25 Jun 2014 23:55:03 +0100 Subject: [PATCH] arm64: Add CONFIG_CC_STACKPROTECTOR arm64 currently lacks support for -fstack-protector. Add similar functionality to arm to detect stack corruption. Acked-by: Will Deacon Acked-by: Kees Cook Signed-off-by: Laura Abbott Signed-off-by: Catalin Marinas --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/stackprotector.h | 38 +++++++++++++++++++++++++ arch/arm64/kernel/process.c | 6 ++++ 3 files changed, 45 insertions(+) create mode 100644 arch/arm64/include/asm/stackprotector.h diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index a474de346be6..f865436096b6 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -32,6 +32,7 @@ config ARM64 select HAVE_ARCH_KGDB select HAVE_ARCH_TRACEHOOK select HAVE_C_RECORDMCOUNT + select HAVE_CC_STACKPROTECTOR select HAVE_DEBUG_BUGVERBOSE select HAVE_DEBUG_KMEMLEAK select HAVE_DMA_API_DEBUG diff --git a/arch/arm64/include/asm/stackprotector.h b/arch/arm64/include/asm/stackprotector.h new file mode 100644 index 000000000000..fe5e287dc56b --- /dev/null +++ b/arch/arm64/include/asm/stackprotector.h @@ -0,0 +1,38 @@ +/* + * 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 + +#include +#include + +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 */ diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 43b7c34f92cb..1309d64aa926 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -51,6 +51,12 @@ #include #include +#ifdef CONFIG_CC_STACKPROTECTOR +#include +unsigned long __stack_chk_guard __read_mostly; +EXPORT_SYMBOL(__stack_chk_guard); +#endif + static void setup_restart(void) { /* -- 2.20.1