From patchwork Thu Jul 12 00:03:37 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 10520709 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5A153600CA for ; Thu, 12 Jul 2018 00:04:32 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 47838293CA for ; Thu, 12 Jul 2018 00:04:32 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3A768286AE; Thu, 12 Jul 2018 00:04:32 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 1A858286AE for ; Thu, 12 Jul 2018 00:04:30 +0000 (UTC) Received: (qmail 14213 invoked by uid 550); 12 Jul 2018 00:04:28 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 14129 invoked from network); 12 Jul 2018 00:04:24 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:mime-version:content-disposition; bh=jih1a/l/LOpgoTURjBQgUE+HeOEANJI4RzwO5+5TF+A=; b=Y8BnAM4+9hyhvcrlhP3PnPJP1w6aMNonqFkbf1TFun/neUEkHyLwmRVdo1bbBISUva wRCCmpN9dUuWFuoLqNonQxBeuDaA+F1+WAAw/diHqZpk5d6WmcvAHWfL14BLBPvyp0OI U6fEeH5GNtm9+V3aa+qgBfuG7PXUzdrF8ysBw= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition; bh=jih1a/l/LOpgoTURjBQgUE+HeOEANJI4RzwO5+5TF+A=; b=brn2LBkzkmbllTqBFaJ+TfO1j9yEJyVujlmAi0wEJKkPSi+L7kBBpqijx4UZez7bjx EMNlq8erOV3driUuJwHZ6YiWqSYe1ToK2mX8qqJayWQ6gzHxdZMI69qO52DkO1Oaa4Eo CkJe9A+18VSrLleLZIjjmuUIlW7L3uCd+8p/rOyEPUAKFf1QB21In4U8xEfUj50V5cBe V4ao0/NEelqEc+TNdYmFAgHA83dzZ39SUpeRD8Sy1ZiNkfmeCWDr7qRpwi/uLyebB78z 2N5qghzPZ+aS00yGgbMyICCxB87rGD+XJkUw6P9A0XFVh0Mxnhgczxn761WZVK+ZVb+F oHhw== X-Gm-Message-State: AOUpUlETZKaTWJ65L0cM5weD9P5k9wlKS3UI8vTjI54mDxT2ZZ1prJ4e E+M2SIY7/Wri9lDOCH7lrIg7PQ== X-Google-Smtp-Source: AAOMgpd12JTXx3x3HCSZz9JISOEjQlMAn6TOFSrAmCllgQSiT3XT66pxu94NXvOHW7hKyRXxN2ekjA== X-Received: by 2002:a17:902:b587:: with SMTP id a7-v6mr639096pls.225.1531353820623; Wed, 11 Jul 2018 17:03:40 -0700 (PDT) Date: Wed, 11 Jul 2018 17:03:37 -0700 From: Kees Cook To: Will Deacon Cc: Laura Abbott , Mark Rutland , Ard Biesheuvel , Kernel Hardening , LKML , linux-arm-kernel , Alexander Popov , Catalin Marinas Subject: [PATCH] arm64: Add support for STACKLEAK gcc plugin Message-ID: <20180712000337.GA4022@beast> MIME-Version: 1.0 Content-Disposition: inline X-Virus-Scanned: ClamAV using ClamSMTP From: Laura Abbott This adds support for the STACKLEAK gcc plugin to arm64 by implementing stackleak_check_alloca(), based heavily on the x86 version, and adding the two helpers used by the stackleak common code: current_top_of_stack() and on_thread_stack(). The stack erasure calls are made at syscall returns. Additionally, this disables the plugin in hypervisor and EFI stub code, which are out of scope for the protection. Signed-off-by: Laura Abbott [kees: add cast to current_top_of_stack(), tweak commit log & comments] Signed-off-by: Kees Cook --- This is tweaked to be stand-alone from Alexander's series so it can land via the arm64 tree. (Alexander's v14 pulled one change out already, and I've lifted the last remaining: the newly needed include in stackleak.h) --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/processor.h | 10 ++++++++++ arch/arm64/kernel/entry.S | 7 +++++++ arch/arm64/kernel/process.c | 16 ++++++++++++++++ arch/arm64/kvm/hyp/Makefile | 3 ++- drivers/firmware/efi/libstub/Makefile | 3 ++- 6 files changed, 38 insertions(+), 2 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 42c090cf0292..216d36a49ab5 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -96,6 +96,7 @@ config ARM64 select HAVE_ARCH_MMAP_RND_BITS select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT select HAVE_ARCH_SECCOMP_FILTER + select HAVE_ARCH_STACKLEAK select HAVE_ARCH_THREAD_STRUCT_WHITELIST select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index a73ae1e49200..ca856bda2051 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -266,5 +266,15 @@ extern void __init minsigstksz_setup(void); #define SVE_SET_VL(arg) sve_set_current_vl(arg) #define SVE_GET_VL() sve_get_current_vl() +/* + * For the STACKLEAK gcc plugin. + * + * These need to be macros because otherwise we get stuck in a nightmare + * of header definitions for the use of task_stack_page. + */ +#define current_top_of_stack() ((unsigned long)task_stack_page(current) + \ + THREAD_SIZE) +#define on_thread_stack() (on_task_stack(current, current_stack_pointer)) + #endif /* __ASSEMBLY__ */ #endif /* __ASM_PROCESSOR_H */ diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 28ad8799406f..80bc93d971f7 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -431,6 +431,11 @@ tsk .req x28 // current thread_info .text + .macro stackleak_erase +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK + bl stackleak_erase_kstack +#endif + .endm /* * Exception vectors. */ @@ -910,6 +915,7 @@ ret_fast_syscall: and x2, x1, #_TIF_WORK_MASK cbnz x2, work_pending enable_step_tsk x1, x2 + stackleak_erase kernel_exit 0 ret_fast_syscall_trace: enable_daif @@ -936,6 +942,7 @@ ret_to_user: cbnz x2, work_pending finish_ret_to_user: enable_step_tsk x1, x2 + stackleak_erase kernel_exit 0 ENDPROC(ret_to_user) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index e10bc363f533..d99281b476b0 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -493,3 +493,19 @@ void arch_setup_new_exec(void) { current->mm->context.flags = is_compat_task() ? MMCF_AARCH32 : 0; } + +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +#define MIN_STACK_LEFT 256 + +void __used stackleak_check_alloca(unsigned long size) +{ + unsigned long sp, stack_left; + + sp = current_stack_pointer; + + stack_left = sp & (THREAD_SIZE - 1); + BUG_ON(stack_left < MIN_STACK_LEFT || + size >= stack_left - MIN_STACK_LEFT); +} +EXPORT_SYMBOL(stackleak_check_alloca); +#endif diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile index 4313f7475333..2fabc2dc1966 100644 --- a/arch/arm64/kvm/hyp/Makefile +++ b/arch/arm64/kvm/hyp/Makefile @@ -3,7 +3,8 @@ # Makefile for Kernel-based Virtual Machine module, HYP part # -ccflags-y += -fno-stack-protector -DDISABLE_BRANCH_PROFILING +ccflags-y += -fno-stack-protector -DDISABLE_BRANCH_PROFILING \ + $(DISABLE_STACKLEAK_PLUGIN) KVM=../../../../virt/kvm diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index a34e9290a699..25dd2a14560d 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -20,7 +20,8 @@ cflags-$(CONFIG_EFI_ARMSTUB) += -I$(srctree)/scripts/dtc/libfdt KBUILD_CFLAGS := $(cflags-y) -DDISABLE_BRANCH_PROFILING \ -D__NO_FORTIFY \ $(call cc-option,-ffreestanding) \ - $(call cc-option,-fno-stack-protector) + $(call cc-option,-fno-stack-protector) \ + $(DISABLE_STACKLEAK_PLUGIN) GCOV_PROFILE := n KASAN_SANITIZE := n