From patchwork Wed Sep 7 01:48:09 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Guo Ren X-Patchwork-Id: 604054 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 2172FECAAD5 for ; Wed, 7 Sep 2022 01:48:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229482AbiIGBsV (ORCPT ); Tue, 6 Sep 2022 21:48:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42334 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229463AbiIGBsV (ORCPT ); Tue, 6 Sep 2022 21:48:21 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 921D0832E3; Tue, 6 Sep 2022 18:48:20 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 27B52616EB; Wed, 7 Sep 2022 01:48:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B8543C433D6; Wed, 7 Sep 2022 01:48:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1662515299; bh=t0Bxth8FdzneHjCPM3qPz7rrGj6ZZLOPNu/D055k2Rk=; h=From:To:Cc:Subject:Date:From; b=dkqwzy2EekUlmtvtOnaFGKlnP2G8hjNUGqKmPiR9Tb7NOu1cFbmZiq9olQIcpd35V 1CqL8B5Hf7u3LGeQvRtb9ducJkSz2MZeZYQ6snuLRcpiFCwrdTXBW69rWXuJrqBK98 McJ+1pJSQS2iVsMTtXubIxBsG0xIEIfquBbV+6EeK4wj4+36zq5r0U2zA0AwB21Dco mqHKC5QisDCEI9RLc4VWRrlwBmbh8CyZIOwu4a4q7ARNwqSgvQwd/3SAguIUHKD2xI nTSNlYOkCvznpWefQgKFhzTTUGiJt/Sdx6BsKvWlxN7GYKWU8LJrDdjfoEcH0aQMqx M3QxFrjQceFpg== From: guoren@kernel.org To: tglx@linutronix.de, peterz@infradead.org, luto@kernel.org, Conor.Dooley@microchip.com, xianting.tian@linux.alibaba.com, daolu@rivosinc.com, arnd@arndb.de Cc: linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, linux-security-module@vger.kernel.org, Guo Ren , Guo Ren Subject: [RFC PATCH] generic_entry: Add stackleak support Date: Tue, 6 Sep 2022 21:48:09 -0400 Message-Id: <20220907014809.919979-1-guoren@kernel.org> X-Mailer: git-send-email 2.36.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org From: Guo Ren Make generic_entry supports basic STACKLEAK, and no arch custom code is needed. Signed-off-by: Guo Ren Signed-off-by: Guo Ren --- drivers/firmware/efi/libstub/Makefile | 4 +++- include/linux/stackleak.h | 3 +++ kernel/entry/common.c | 5 +++++ security/Kconfig.hardening | 2 +- 4 files changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index d0537573501e..bb6ad37a9690 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -19,7 +19,7 @@ cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ \ # arm64 uses the full KBUILD_CFLAGS so it's necessary to explicitly # disable the stackleak plugin cflags-$(CONFIG_ARM64) := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \ - -fpie $(DISABLE_STACKLEAK_PLUGIN) \ + -fpie \ $(call cc-option,-mbranch-protection=none) cflags-$(CONFIG_ARM) := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \ -fno-builtin -fpic \ @@ -27,6 +27,8 @@ cflags-$(CONFIG_ARM) := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \ cflags-$(CONFIG_RISCV) := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \ -fpic +cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) += $(DISABLE_STACKLEAK_PLUGIN) + cflags-$(CONFIG_EFI_GENERIC_STUB) += -I$(srctree)/scripts/dtc/libfdt KBUILD_CFLAGS := $(cflags-y) -Os -DDISABLE_BRANCH_PROFILING \ diff --git a/include/linux/stackleak.h b/include/linux/stackleak.h index c36e7a3b45e7..9890802a5868 100644 --- a/include/linux/stackleak.h +++ b/include/linux/stackleak.h @@ -76,8 +76,11 @@ static inline void stackleak_task_init(struct task_struct *t) # endif } +void noinstr stackleak_erase(void); + #else /* !CONFIG_GCC_PLUGIN_STACKLEAK */ static inline void stackleak_task_init(struct task_struct *t) { } +static inline void stackleak_erase(void) {} #endif #endif diff --git a/kernel/entry/common.c b/kernel/entry/common.c index 063068a9ea9b..6acb1d6a1396 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -8,6 +8,7 @@ #include #include #include +#include #include "common.h" @@ -194,6 +195,10 @@ static void exit_to_user_mode_prepare(struct pt_regs *regs) lockdep_assert_irqs_disabled(); +#ifndef CONFIG_HAVE_ARCH_STACKLEAK + stackleak_erase(); +#endif + /* Flush pending rcuog wakeup before the last need_resched() check */ tick_nohz_user_enter_prepare(); diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening index bd2aabb2c60f..3329482beb8d 100644 --- a/security/Kconfig.hardening +++ b/security/Kconfig.hardening @@ -152,7 +152,7 @@ config GCC_PLUGIN_STRUCTLEAK_VERBOSE config GCC_PLUGIN_STACKLEAK bool "Poison kernel stack before returning from syscalls" depends on GCC_PLUGINS - depends on HAVE_ARCH_STACKLEAK + depends on HAVE_ARCH_STACKLEAK || GENERIC_ENTRY help This option makes the kernel erase the kernel stack before returning from system calls. This has the effect of leaving