From patchwork Mon Oct 2 19:20:06 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 9981177 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 63B066029B for ; Mon, 2 Oct 2017 19:20:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 56A2428867 for ; Mon, 2 Oct 2017 19:20:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4B6FA288D8; Mon, 2 Oct 2017 19:20:57 +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=-4.1 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,T_DKIM_INVALID 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 EB77028867 for ; Mon, 2 Oct 2017 19:20:54 +0000 (UTC) Received: (qmail 29942 invoked by uid 550); 2 Oct 2017 19:20:33 -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 29757 invoked from network); 2 Oct 2017 19:20:28 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=zh0hGZ8XrD3wLqFJKCOca1QQd4Gg9v4mQnWKeDQGGxQ=; b=ZHR/W0MFTMpM/wBQeogmLKqo0UwfA5lmE+zJF9n7HFnItIRapXIzOhMWg7R6PK0jG5 kmDNh+Eq/MdCHULaPw3qc4lApNR/tx/INODtGLHiDyAsGOm7SdEPdA8bLn1LUj6TlmsN rBeugTYE8xTKTPKJHVveXbMdQuQyhUTuRrgV0= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=zh0hGZ8XrD3wLqFJKCOca1QQd4Gg9v4mQnWKeDQGGxQ=; b=AF8PN6h9W7n+vaew6DWOWUgpQcZS6qtFIRI6ddSeytyCXWK3jBrVB/P1qjxwEtG8RT sDZatOy0344FVoGDI6kyN3PgcIlXZmgLuHa/CHuRUHLzSB6lYggmEwkp1pBmZwbfy6nD 7iJTRW7SgQI99fD7joi9SiQEOF1yu7ot6sYVnM/+J93kMhEiICZRIcu0rwwbkvdV3Tem ilh3Alygc0aqkpAzb2KQmxhTPhRZEzcowLp/tOfjRIxtGTSnOMX2pFMORbwPfRsUNU0q pqa+P0btkAtFGo4/YpMqJ2j2EqZNFKbcEhDa96HC5N8dp51HkFVQxQrK36yGmuHwb4WJ eRYQ== X-Gm-Message-State: AHPjjUivmbqKw+0ltWx6f58waHQFNg7TQmtMmuehHsDYmcsrpLKbX0Xa 7512XEApUg3l1dznzuOJSYIkcQ== X-Google-Smtp-Source: AOwi7QA1D1FbR8cTx4NihgUVWcAvMPPi3aeOMJNPBi9vAga6sGKYl4g1LQv4W6SaiFbF37fs9eANXg== X-Received: by 10.98.209.73 with SMTP id t9mr15389042pfl.52.1506972017242; Mon, 02 Oct 2017 12:20:17 -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 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> Subject: [kernel-hardening] [PATCH 2/3] Makefile: Move stackprotector availability out of Kconfig 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: