From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kees Cook Subject: [PATCH v5 36/36] arm/build: Assert for unwanted sections Date: Fri, 31 Jul 2020 16:08:20 -0700 Message-ID: <20200731230820.1742553-37-keescook@chromium.org> References: <20200731230820.1742553-1-keescook@chromium.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45852 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727982AbgGaXIv (ORCPT ); Fri, 31 Jul 2020 19:08:51 -0400 Received: from mail-pl1-x642.google.com (mail-pl1-x642.google.com [IPv6:2607:f8b0:4864:20::642]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6BBCAC061290 for ; Fri, 31 Jul 2020 16:08:51 -0700 (PDT) Received: by mail-pl1-x642.google.com with SMTP id g19so5527761plq.0 for ; Fri, 31 Jul 2020 16:08:51 -0700 (PDT) In-Reply-To: <20200731230820.1742553-1-keescook@chromium.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Thomas Gleixner , Will Deacon Cc: Kees Cook , Catalin Marinas , Mark Rutland , Ard Biesheuvel , Peter Collingbourne , James Morse , Borislav Petkov , Ingo Molnar , Russell King , Masahiro Yamada , Arvind Sankar , Nick Desaulniers , Nathan Chancellor , Arnd Bergmann , x86@kernel.org, clang-built-linux@googlegroups.com, linux-arch@vger.kernel.org, linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org In preparation for warning on orphan sections, enforce expected-to-be-zero-sized sections (since discarding them might hide problems with them suddenly gaining unexpected entries). Signed-off-by: Kees Cook --- arch/arm/include/asm/vmlinux.lds.h | 10 ++++++++++ arch/arm/kernel/vmlinux-xip.lds.S | 2 ++ arch/arm/kernel/vmlinux.lds.S | 2 ++ 3 files changed, 14 insertions(+) diff --git a/arch/arm/include/asm/vmlinux.lds.h b/arch/arm/include/asm/vmlinux.lds.h index 6624dd97475c..e0d49fd756f7 100644 --- a/arch/arm/include/asm/vmlinux.lds.h +++ b/arch/arm/include/asm/vmlinux.lds.h @@ -52,6 +52,16 @@ ARM_MMU_DISCARD(*(__ex_table)) \ COMMON_DISCARDS +/* + * Sections that should stay zero sized, which is safer to explicitly + * check instead of blindly discarding. + */ +#define ARM_ASSERTS \ + .plt (NOLOAD) : { \ + *(.iplt) *(.rel.iplt) *(.iplt) *(.igot.plt) \ + } \ + ASSERT(SIZEOF(.plt) == 0, "Unexpected run-time procedure linkages detected!") + #define ARM_DETAILS \ ELF_DETAILS \ .ARM.attributes 0 : { *(.ARM.attributes) } diff --git a/arch/arm/kernel/vmlinux-xip.lds.S b/arch/arm/kernel/vmlinux-xip.lds.S index 11ffa79751da..50136828f5b5 100644 --- a/arch/arm/kernel/vmlinux-xip.lds.S +++ b/arch/arm/kernel/vmlinux-xip.lds.S @@ -152,6 +152,8 @@ SECTIONS STABS_DEBUG DWARF_DEBUG ARM_DETAILS + + ARM_ASSERTS } /* diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S index dc672fe35de3..5f4922e858d0 100644 --- a/arch/arm/kernel/vmlinux.lds.S +++ b/arch/arm/kernel/vmlinux.lds.S @@ -151,6 +151,8 @@ SECTIONS STABS_DEBUG DWARF_DEBUG ARM_DETAILS + + ARM_ASSERTS } #ifdef CONFIG_STRICT_KERNEL_RWX -- 2.25.1