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[173.164.112.133]) by smtp.gmail.com with ESMTPSA id e66sm16580697pfb.48.2017.10.02.12.20.12 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 02 Oct 2017 12:20:12 -0700 (PDT) From: Kees Cook To: Andrew Morton Cc: Kees Cook , Masahiro Yamada , Michal Marek , Ingo Molnar , Laura Abbott , Nicholas Piggin , Al Viro , linux-kbuild@vger.kernel.org, Yoshinori Sato , Rich Felker , "David S. Miller" , linux-kernel@vger.kernel.org, linux-sh@vger.kernel.org, kernel-hardening@lists.openwall.com Subject: [PATCH 2/3] Makefile: Move stackprotector availability out of Kconfig Date: Mon, 2 Oct 2017 12:20:06 -0700 Message-Id: <1506972007-80614-3-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1506972007-80614-1-git-send-email-keescook@chromium.org> References: <1506972007-80614-1-git-send-email-keescook@chromium.org> Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Various portions of the kernel, especially per-architecture pieces, need to know if the compiler is building it 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: Michal Marek Cc: Andrew Morton Cc: Ingo Molnar Cc: Laura Abbott Cc: Nicholas Piggin Cc: Al Viro Cc: linux-kbuild@vger.kernel.org Signed-off-by: Kees Cook --- Makefile | 7 +++++-- arch/Kconfig | 8 -------- 2 files changed, 5 insertions(+), 10 deletions(-) diff --git a/Makefile b/Makefile index d1119941261c..e122a9cf0399 100644 --- a/Makefile +++ b/Makefile @@ -688,8 +688,11 @@ else stackp-flag := $(call cc-option, -fno-stack-protector) endif endif -# Find arch-specific stack protector compiler sanity-checking script. -ifdef CONFIG_CC_STACKPROTECTOR +ifdef stackp-name + # If the stack protector has been selected, inform the rest of the build. + KBUILD_CFLAGS += -DCONFIG_CC_STACKPROTECTOR + KBUILD_AFLAGS += -DCONFIG_CC_STACKPROTECTOR + # Find arch-specific stack protector compiler sanity-checking script. stackp-path := $(srctree)/scripts/gcc-$(SRCARCH)_$(BITS)-has-stack-protector.sh stackp-check := $(wildcard $(stackp-path)) endif 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: