From mboxrd@z Thu Jan 1 00:00:00 1970 From: guoren@kernel.org Subject: [PATCH 2/5] csky: Initial stack protector support Date: Mon, 30 Dec 2019 16:23:28 +0800 Message-ID: <20191230082331.30976-2-guoren@kernel.org> References: <20191230082331.30976-1-guoren@kernel.org> Return-path: In-Reply-To: <20191230082331.30976-1-guoren@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: linux-csky@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, arnd@arndb.de, Mao Han , Guo Ren List-Id: linux-arch.vger.kernel.org From: Mao Han This is a basic -fstack-protector support without per-task canary switching. The protector will report something like when stack corruption is detected: It's tested with strcpy local array overflow in sys_kill and get: stack-protector: Kernel stack is corrupted in: sys_kill+0x23c/0x23c TODO: - Support task switch for different cannary Signed-off-by: Mao Han Signed-off-by: Guo Ren --- arch/csky/Kconfig | 1 + arch/csky/include/asm/stackprotector.h | 29 ++++++++++++++++++++++++++ arch/csky/kernel/process.c | 6 ++++++ 3 files changed, 36 insertions(+) create mode 100644 arch/csky/include/asm/stackprotector.h diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig index 3973847b5f42..285234300740 100644 --- a/arch/csky/Kconfig +++ b/arch/csky/Kconfig @@ -48,6 +48,7 @@ config CSKY select HAVE_PERF_USER_STACK_DUMP select HAVE_DMA_API_DEBUG select HAVE_DMA_CONTIGUOUS + select HAVE_STACKPROTECTOR select HAVE_SYSCALL_TRACEPOINTS select MAY_HAVE_SPARSE_IRQ select MODULES_USE_ELF_RELA if MODULES diff --git a/arch/csky/include/asm/stackprotector.h b/arch/csky/include/asm/stackprotector.h new file mode 100644 index 000000000000..d7cd4e51edd9 --- /dev/null +++ b/arch/csky/include/asm/stackprotector.h @@ -0,0 +1,29 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_STACKPROTECTOR_H +#define _ASM_STACKPROTECTOR_H 1 + +#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; + canary &= CANARY_MASK; + + current->stack_canary = canary; + __stack_chk_guard = current->stack_canary; +} + +#endif /* __ASM_SH_STACKPROTECTOR_H */ diff --git a/arch/csky/kernel/process.c b/arch/csky/kernel/process.c index f320d9248a22..5349cd8c0f30 100644 --- a/arch/csky/kernel/process.c +++ b/arch/csky/kernel/process.c @@ -16,6 +16,12 @@ struct cpuinfo_csky cpu_data[NR_CPUS]; +#ifdef CONFIG_STACKPROTECTOR +#include +unsigned long __stack_chk_guard __read_mostly; +EXPORT_SYMBOL(__stack_chk_guard); +#endif + asmlinkage void ret_from_fork(void); asmlinkage void ret_from_kernel_thread(void); -- 2.17.0 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:47690 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727175AbfL3IX7 (ORCPT ); Mon, 30 Dec 2019 03:23:59 -0500 From: guoren@kernel.org Subject: [PATCH 2/5] csky: Initial stack protector support Date: Mon, 30 Dec 2019 16:23:28 +0800 Message-ID: <20191230082331.30976-2-guoren@kernel.org> In-Reply-To: <20191230082331.30976-1-guoren@kernel.org> References: <20191230082331.30976-1-guoren@kernel.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-csky@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, arnd@arndb.de, Mao Han , Guo Ren Message-ID: <20191230082328.4YS55YfGP5rjNLZ0H0wh7ZREVwGmnhEpah7jO5yIcug@z> From: Mao Han This is a basic -fstack-protector support without per-task canary switching. The protector will report something like when stack corruption is detected: It's tested with strcpy local array overflow in sys_kill and get: stack-protector: Kernel stack is corrupted in: sys_kill+0x23c/0x23c TODO: - Support task switch for different cannary Signed-off-by: Mao Han Signed-off-by: Guo Ren --- arch/csky/Kconfig | 1 + arch/csky/include/asm/stackprotector.h | 29 ++++++++++++++++++++++++++ arch/csky/kernel/process.c | 6 ++++++ 3 files changed, 36 insertions(+) create mode 100644 arch/csky/include/asm/stackprotector.h diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig index 3973847b5f42..285234300740 100644 --- a/arch/csky/Kconfig +++ b/arch/csky/Kconfig @@ -48,6 +48,7 @@ config CSKY select HAVE_PERF_USER_STACK_DUMP select HAVE_DMA_API_DEBUG select HAVE_DMA_CONTIGUOUS + select HAVE_STACKPROTECTOR select HAVE_SYSCALL_TRACEPOINTS select MAY_HAVE_SPARSE_IRQ select MODULES_USE_ELF_RELA if MODULES diff --git a/arch/csky/include/asm/stackprotector.h b/arch/csky/include/asm/stackprotector.h new file mode 100644 index 000000000000..d7cd4e51edd9 --- /dev/null +++ b/arch/csky/include/asm/stackprotector.h @@ -0,0 +1,29 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_STACKPROTECTOR_H +#define _ASM_STACKPROTECTOR_H 1 + +#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; + canary &= CANARY_MASK; + + current->stack_canary = canary; + __stack_chk_guard = current->stack_canary; +} + +#endif /* __ASM_SH_STACKPROTECTOR_H */ diff --git a/arch/csky/kernel/process.c b/arch/csky/kernel/process.c index f320d9248a22..5349cd8c0f30 100644 --- a/arch/csky/kernel/process.c +++ b/arch/csky/kernel/process.c @@ -16,6 +16,12 @@ struct cpuinfo_csky cpu_data[NR_CPUS]; +#ifdef CONFIG_STACKPROTECTOR +#include +unsigned long __stack_chk_guard __read_mostly; +EXPORT_SYMBOL(__stack_chk_guard); +#endif + asmlinkage void ret_from_fork(void); asmlinkage void ret_from_kernel_thread(void); -- 2.17.0