From patchwork Sun Aug 28 13:54:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xianting Tian X-Patchwork-Id: 601268 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C52F5ECAAD5 for ; Sun, 28 Aug 2022 13:54:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229500AbiH1NyT (ORCPT ); Sun, 28 Aug 2022 09:54:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52614 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229470AbiH1NyS (ORCPT ); Sun, 28 Aug 2022 09:54:18 -0400 Received: from out30-56.freemail.mail.aliyun.com (out30-56.freemail.mail.aliyun.com [115.124.30.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C28F830574; Sun, 28 Aug 2022 06:54:16 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R151e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=ay29a033018045192; MF=xianting.tian@linux.alibaba.com; NM=1; PH=DS; RN=10; SR=0; TI=SMTPD_---0VNSFve4_1661694851; Received: from localhost(mailfrom:xianting.tian@linux.alibaba.com fp:SMTPD_---0VNSFve4_1661694851) by smtp.aliyun-inc.com; Sun, 28 Aug 2022 21:54:12 +0800 From: Xianting Tian To: paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, ardb@kernel.org, guoren@kernel.org, heiko@sntech.de Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, Xianting Tian Subject: [PATCH] RISC-V: Add STACKLEAK erasing the kernel stack at the end of syscalls Date: Sun, 28 Aug 2022 21:54:07 +0800 Message-Id: <20220828135407.3897717-1-xianting.tian@linux.alibaba.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org This adds support for the STACKLEAK gcc plugin to RISC-V and disables the plugin in EFI stub code, which is out of scope for the protection. For the benefits of STACKLEAK feature, please check the commit afaef01c0015 ("x86/entry: Add STACKLEAK erasing the kernel stack at the end of syscalls") Performance impact (tested on qemu env with 1 riscv64 hart, 1GB mem) hackbench -s 512 -l 200 -g 15 -f 25 -P 2.0% slowdown Signed-off-by: Xianting Tian --- arch/riscv/Kconfig | 1 + arch/riscv/include/asm/processor.h | 4 ++++ arch/riscv/kernel/entry.S | 3 +++ drivers/firmware/efi/libstub/Makefile | 2 +- 4 files changed, 9 insertions(+), 1 deletion(-) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index ed66c31e4655..61fd0dad4463 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -85,6 +85,7 @@ config RISCV select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE select HAVE_ARCH_THREAD_STRUCT_WHITELIST select HAVE_ARCH_VMAP_STACK if MMU && 64BIT + select HAVE_ARCH_STACKLEAK select HAVE_ASM_MODVERSIONS select HAVE_CONTEXT_TRACKING_USER select HAVE_DEBUG_KMEMLEAK diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h index 19eedd4af4cd..75620c467d25 100644 --- a/arch/riscv/include/asm/processor.h +++ b/arch/riscv/include/asm/processor.h @@ -85,6 +85,10 @@ int riscv_of_parent_hartid(struct device_node *node, unsigned long *hartid); extern void riscv_fill_hwcap(void); extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src); +#define current_top_of_stack() ((unsigned long)current->stack + THREAD_SIZE) +#define on_thread_stack() ((unsigned long)((current_top_of_stack() \ + - current_stack_pointer) < THREAD_SIZE)) + #endif /* __ASSEMBLY__ */ #endif /* _ASM_RISCV_PROCESSOR_H */ diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S index b9eda3fcbd6d..5f98660b46d4 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -233,6 +233,9 @@ check_syscall_nr: ret_from_syscall: /* Set user a0 to kernel a0 */ REG_S a0, PT_A0(sp) +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK + call stackleak_erase_on_task_stack +#endif /* * We didn't execute the actual syscall. * Seccomp already set return value for the current task pt_regs. diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index d0537573501e..5e1fc4f82883 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -25,7 +25,7 @@ cflags-$(CONFIG_ARM) := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \ -fno-builtin -fpic \ $(call cc-option,-mno-single-pic-base) cflags-$(CONFIG_RISCV) := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \ - -fpic + -fpic $(DISABLE_STACKLEAK_PLUGIN) cflags-$(CONFIG_EFI_GENERIC_STUB) += -I$(srctree)/scripts/dtc/libfdt