From patchwork Tue Nov 2 07:58:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Li X-Patchwork-Id: 12598091 X-Patchwork-Delegate: keescook@chromium.org 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 29646C433EF for ; Tue, 2 Nov 2021 07:58:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E7C061051 for ; Tue, 2 Nov 2021 07:58:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230497AbhKBIA7 (ORCPT ); Tue, 2 Nov 2021 04:00:59 -0400 Received: from out30-133.freemail.mail.aliyun.com ([115.124.30.133]:36522 "EHLO out30-133.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230451AbhKBIA7 (ORCPT ); Tue, 2 Nov 2021 04:00:59 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R891e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04423;MF=ashimida@linux.alibaba.com;NM=1;PH=DS;RN=25;SR=0;TI=SMTPD_---0Uuj7Ztb_1635839894; Received: from localhost(mailfrom:ashimida@linux.alibaba.com fp:SMTPD_---0Uuj7Ztb_1635839894) by smtp.aliyun-inc.com(127.0.0.1); Tue, 02 Nov 2021 15:58:21 +0800 From: Dan Li To: catalin.marinas@arm.com, will@kernel.org, nathan@kernel.org, ndesaulniers@google.com, keescook@chromium.org, tglx@linutronix.de, akpm@linux-foundation.org, peterz@infradead.org, samitolvanen@google.com, masahiroy@kernel.org, rppt@kernel.org, mark.rutland@arm.com, frederic@kernel.org, yifeifz2@illinois.edu, rostedt@goodmis.org, viresh.kumar@linaro.org, andreyknvl@gmail.com, colin.king@canonical.com, ojeda@kernel.org, arnd@arndb.de, luc.vanoostenryck@gmail.com, nivedita@alum.mit.edu, elver@google.com Cc: linux-hardening@vger.kernel.org, Dan Li Subject: [PATCH] [RFC/RFT] AARCH64: Add gcc Shadow Call Stack support Date: Tue, 2 Nov 2021 00:58:12 -0700 Message-Id: <20211102075812.122715-1-ashimida@linux.alibaba.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org I tried to submit a patch[1] to add compiler's SCS support on gcc-11.1.0. Kernel can enable SCS under gcc based on this patch, commands as follows: make ARCH=arm64 defconfig ./scripts/config -e CONFIG_SHADOW_CALL_STACK make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- [1] https://gcc.gnu.org/pipermail/gcc-patches/2021-November/583062.html Signed-off-by: Dan Li --- This function can be used to test whether the shadow stack is effective: //noinline void __noscs scs_test(void) noinline void scs_test(void) { register unsigned long *sp asm("sp"); unsigned long * lr = sp + 1; asm volatile("":::"x30"); *lr = 0; } ffff800010012710 : ffff800010012710: d503245f bti c ffff800010012714: d503233f paciasp ffff800010012718: a9bf7bfd stp x29, x30, [sp, #-16]! ffff80001001271c: 910003fd mov x29, sp ffff800010012720: 910003e0 mov x0, sp ffff800010012724: f900041f str xzr, [x0, #8] ffff800010012728: a8c17bfd ldp x29, x30, [sp], #16 ffff80001001272c: d50323bf autiasp ffff800010012730: d65f03c0 ret arch/Kconfig | 6 +++--- arch/arm64/Kconfig | 2 +- include/linux/compiler-gcc.h | 6 ++++++ 3 files changed, 10 insertions(+), 4 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index 98db63496bab..35b27be0d7ee 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -593,11 +593,11 @@ config ARCH_SUPPORTS_SHADOW_CALL_STACK switching. config SHADOW_CALL_STACK - bool "Clang Shadow Call Stack" - depends on CC_IS_CLANG && ARCH_SUPPORTS_SHADOW_CALL_STACK + bool "Shadow Call Stack" + depends on ARCH_SUPPORTS_SHADOW_CALL_STACK depends on DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER help - This option enables Clang's Shadow Call Stack, which uses a + This option enables Clang/GCC's Shadow Call Stack, which uses a shadow stack to protect function return addresses from being overwritten by an attacker. More information can be found in Clang's documentation: diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 62c3c1d2190f..5d49c0c89645 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1062,7 +1062,7 @@ config ARCH_HAS_FILTER_PGPROT # Supported by clang >= 7.0 config CC_HAVE_SHADOW_CALL_STACK - def_bool $(cc-option, -fsanitize=shadow-call-stack -ffixed-x18) + def_bool CC_IS_CLANG || $(cc-option, -fsanitize=shadow-call-stack -ffixed-x18) config PARAVIRT bool "Enable paravirtualization code" diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index cb9217fc60af..917c3bb6aa43 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -104,6 +104,12 @@ #define KASAN_ABI_VERSION 3 #endif +#if __has_attribute(__no_sanitize_shadow_call_stack__) +#define __noscs __attribute__((no_sanitize_shadow_call_stack)) +#else +#define __noscs +#endif + #if __has_attribute(__no_sanitize_address__) #define __no_sanitize_address __attribute__((no_sanitize_address)) #else