From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753258AbdKGRjl (ORCPT ); Tue, 7 Nov 2017 12:39:41 -0500 Received: from mail-pf0-f195.google.com ([209.85.192.195]:53407 "EHLO mail-pf0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752305AbdKGRi4 (ORCPT ); Tue, 7 Nov 2017 12:38:56 -0500 X-Google-Smtp-Source: ABhQp+QI4eKlLFA8X5AahtVezb6+FbtzowzXzYk9K0TcLcfybztaynWXFyPFBGBUn9GkGb16KdQwrg== From: Kees Cook To: Andrew Morton Cc: Kees Cook , Masahiro Yamada , Arnd Bergmann , linux-kbuild@vger.kernel.org, Josh Triplett , Nicholas Piggin , Laura Abbott , linux-kernel@vger.kernel.org Subject: [PATCH v2 2/3] Makefile: Move stack-protector availability out of Kconfig Date: Tue, 7 Nov 2017 09:38:39 -0800 Message-Id: <1510076320-69931-3-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1510076320-69931-1-git-send-email-keescook@chromium.org> References: <1510076320-69931-1-git-send-email-keescook@chromium.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Various portions of the kernel, especially per-architecture pieces, need to know if the compiler is building with the stack protector. This was done in the arch/Kconfig with 'select', but this doesn't allow a way to do auto-detected compiler support. In preparation for creating an on-if-available default, move the logic for the definition of CONFIG_CC_STACKPROTECTOR into the Makefile. Cc: Masahiro Yamada Cc: Arnd Bergmann Cc: linux-kbuild@vger.kernel.org Signed-off-by: Kees Cook --- Makefile | 6 +++++- arch/Kconfig | 8 -------- arch/x86/Kconfig | 2 +- 3 files changed, 6 insertions(+), 10 deletions(-) diff --git a/Makefile b/Makefile index caa3f7e6f524..b486c0271866 100644 --- a/Makefile +++ b/Makefile @@ -689,7 +689,7 @@ else endif endif # Find arch-specific stack protector compiler sanity-checking script. -ifdef CONFIG_CC_STACKPROTECTOR +ifdef stackp-name stackp-path := $(srctree)/scripts/gcc-$(SRCARCH)_$(BITS)-has-stack-protector.sh stackp-check := $(wildcard $(stackp-path)) # If the wildcard test matches a test script, run it to check functionality. @@ -698,6 +698,10 @@ ifdef CONFIG_CC_STACKPROTECTOR stackp-broken := y endif endif + ifndef stackp-broken + # If the stack protector is functional, enable code that depends on it. + KBUILD_CPPFLAGS += -DCONFIG_CC_STACKPROTECTOR + endif endif KBUILD_CFLAGS += $(stackp-flag) diff --git a/arch/Kconfig b/arch/Kconfig index 1aafb4efbb51..7007c1bfa79c 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -523,12 +523,6 @@ config HAVE_CC_STACKPROTECTOR - its compiler supports the -fstack-protector option - it has implemented a stack canary (e.g. __stack_chk_guard) -config CC_STACKPROTECTOR - def_bool n - help - Set when a stack-protector mode is enabled, so that the build - can enable kernel-side support for the GCC feature. - choice prompt "Stack Protector buffer overflow detection" depends on HAVE_CC_STACKPROTECTOR @@ -549,7 +543,6 @@ config CC_STACKPROTECTOR_NONE config CC_STACKPROTECTOR_REGULAR bool "Regular" - select CC_STACKPROTECTOR help Functions will have the stack-protector canary logic added if they have an 8-byte or larger character array on the stack. @@ -563,7 +556,6 @@ config CC_STACKPROTECTOR_REGULAR config CC_STACKPROTECTOR_STRONG bool "Strong" - select CC_STACKPROTECTOR help Functions will have the stack-protector canary logic added in any of the following conditions: diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 971feac13506..8d3847071707 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -319,7 +319,7 @@ config X86_64_SMP config X86_32_LAZY_GS def_bool y - depends on X86_32 && !CC_STACKPROTECTOR + depends on X86_32 && CC_STACKPROTECTOR_NONE config ARCH_SUPPORTS_UPROBES def_bool y -- 2.7.4