From mboxrd@z Thu Jan 1 00:00:00 1970 From: lauraa@codeaurora.org (Laura Abbott) Date: Thu, 30 Jan 2014 13:05:44 -0800 Subject: [PATCHv3] arm64: Add CONFIG_CC_STACKPROTECTOR Message-ID: <1391115944-10183-1-git-send-email-lauraa@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org arm64 currently lacks support for -fstack-protector. Add similar functionality to arm to detect stack corruption. Cc: Will Deacon Cc: Catalin Marinas Signed-off-by: Laura Abbott --- I realized today that the patch I gave before was not going to work for recent trees because of changes to CC_STACKPROTECTOR that were not in my working tree before. This should be the patch to actually work against recent kernels. --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/stackprotector.h | 38 +++++++++++++++++++++++++++++++ arch/arm64/kernel/process.c | 6 +++++ 3 files changed, 45 insertions(+), 0 deletions(-) create mode 100644 arch/arm64/include/asm/stackprotector.h diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index dd4327f..2ebf522 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -27,6 +27,7 @@ config ARM64 select HARDIRQS_SW_RESEND select HAVE_ARCH_JUMP_LABEL select HAVE_ARCH_TRACEHOOK + 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 0000000..fe5e287 --- /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 1e5a178..89c301d 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -50,6 +50,12 @@ #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) { /* -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation