From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-x22f.google.com (mail-pg0-x22f.google.com [IPv6:2607:f8b0:400e:c05::22f]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3wtqKH0Q3VzDr2B for ; Fri, 23 Jun 2017 04:06:43 +1000 (AEST) Received: by mail-pg0-x22f.google.com with SMTP id 132so10958179pgb.2 for ; Thu, 22 Jun 2017 11:06:42 -0700 (PDT) From: Kees Cook To: Andrew Morton Cc: Kees Cook , Russell King , Catalin Marinas , Will Deacon , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Martin Schwidefsky , Heiko Carstens , James Hogan , Pratyush Anand , Ingo Molnar , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, kernel-hardening@lists.openwall.com Subject: [PATCH 2/4] arm64: Reduce ELF_ET_DYN_BASE Date: Thu, 22 Jun 2017 11:06:30 -0700 Message-Id: <1498154792-49952-3-git-send-email-keescook@chromium.org> In-Reply-To: <1498154792-49952-1-git-send-email-keescook@chromium.org> References: <1498154792-49952-1-git-send-email-keescook@chromium.org> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Now that explicitly executed loaders are loaded in the mmap region, position PIE binaries lower in the address space to avoid possible collisions with mmap or stack regions. For 64-bit, align to 4GB to allow runtimes to use the entire 32-bit address space for 32-bit pointers. Signed-off-by: Kees Cook --- arch/arm64/include/asm/elf.h | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h index 5d1700425efe..f742af8f7c42 100644 --- a/arch/arm64/include/asm/elf.h +++ b/arch/arm64/include/asm/elf.h @@ -113,12 +113,13 @@ #define ELF_EXEC_PAGESIZE PAGE_SIZE /* - * This is the location that an ET_DYN program is loaded if exec'ed. Typical - * use of this is to invoke "./ld.so someprog" to test out a new version of - * the loader. We need to make sure that it is out of the way of the program - * that it will "exec", and that there is sufficient room for the brk. + * This is the base location for PIE (ET_DYN with INTERP) loads. On + * 64-bit, this is raised to 4GB to leave the entire 32-bit address + * space open for things that want to use the area for 32-bit pointers. */ -#define ELF_ET_DYN_BASE (2 * TASK_SIZE_64 / 3) +#define ELF_ET_DYN_BASE (test_thread_flag(TIF_32BIT) ? \ + 0x000400000UL : \ + 0x100000000UL) #ifndef __ASSEMBLY__ @@ -173,8 +174,6 @@ extern int arch_setup_additional_pages(struct linux_binprm *bprm, #ifdef CONFIG_COMPAT -#define COMPAT_ELF_ET_DYN_BASE (2 * TASK_SIZE_32 / 3) - /* AArch32 registers. */ #define COMPAT_ELF_NGREG 18 typedef unsigned int compat_elf_greg_t; -- 2.7.4