From patchwork Thu Aug 8 06:17:47 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandre Ghiti X-Patchwork-Id: 11083253 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EAE2914DB for ; Thu, 8 Aug 2019 06:23:41 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DCC27286AE for ; Thu, 8 Aug 2019 06:23:41 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D067E28A3D; Thu, 8 Aug 2019 06:23:41 +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=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 71B5228ABE for ; Thu, 8 Aug 2019 06:23:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731043AbfHHGXh (ORCPT ); Thu, 8 Aug 2019 02:23:37 -0400 Received: from relay3-d.mail.gandi.net ([217.70.183.195]:45907 "EHLO relay3-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730626AbfHHGXh (ORCPT ); Thu, 8 Aug 2019 02:23:37 -0400 X-Originating-IP: 79.86.19.127 Received: from alex.numericable.fr (127.19.86.79.rev.sfr.net [79.86.19.127]) (Authenticated sender: alex@ghiti.fr) by relay3-d.mail.gandi.net (Postfix) with ESMTPSA id D423E60002; Thu, 8 Aug 2019 06:23:30 +0000 (UTC) From: Alexandre Ghiti To: Andrew Morton Cc: Paul Walmsley , Luis Chamberlain , Christoph Hellwig , Russell King , Catalin Marinas , Will Deacon , Ralf Baechle , Paul Burton , James Hogan , Palmer Dabbelt , Albert Ou , Alexander Viro , Kees Cook , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Alexandre Ghiti Subject: [PATCH v6 05/14] arm64, mm: Make randomization selected by generic topdown mmap layout Date: Thu, 8 Aug 2019 02:17:47 -0400 Message-Id: <20190808061756.19712-6-alex@ghiti.fr> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190808061756.19712-1-alex@ghiti.fr> References: <20190808061756.19712-1-alex@ghiti.fr> MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This commits selects ARCH_HAS_ELF_RANDOMIZE when an arch uses the generic topdown mmap layout functions so that this security feature is on by default. Note that this commit also removes the possibility for arm64 to have elf randomization and no MMU: without MMU, the security added by randomization is worth nothing. Signed-off-by: Alexandre Ghiti Acked-by: Catalin Marinas Acked-by: Kees Cook Reviewed-by: Christoph Hellwig Reviewed-by: Luis Chamberlain --- arch/Kconfig | 1 + arch/arm64/Kconfig | 1 - arch/arm64/kernel/process.c | 8 -------- mm/util.c | 11 +++++++++-- 4 files changed, 10 insertions(+), 11 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index a0bb6fa4d381..d4c1f0551dfe 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -705,6 +705,7 @@ config HAVE_ARCH_COMPAT_MMAP_BASES config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT bool depends on MMU + select ARCH_HAS_ELF_RANDOMIZE config HAVE_COPY_THREAD_TLS bool diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 14a194e63458..399f595ef852 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -16,7 +16,6 @@ config ARM64 select ARCH_HAS_DMA_MMAP_PGPROT select ARCH_HAS_DMA_PREP_COHERENT select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI - select ARCH_HAS_ELF_RANDOMIZE select ARCH_HAS_FAST_MULTIPLIER select ARCH_HAS_FORTIFY_SOURCE select ARCH_HAS_GCOV_PROFILE_ALL diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index f674f28df663..8ddc2471b054 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -548,14 +548,6 @@ unsigned long arch_align_stack(unsigned long sp) return sp & ~0xf; } -unsigned long arch_randomize_brk(struct mm_struct *mm) -{ - if (is_compat_task()) - return randomize_page(mm->brk, SZ_32M); - else - return randomize_page(mm->brk, SZ_1G); -} - /* * Called from setup_new_exec() after (COMPAT_)SET_PERSONALITY. */ diff --git a/mm/util.c b/mm/util.c index 0781e5575cb3..16f1e56e2996 100644 --- a/mm/util.c +++ b/mm/util.c @@ -321,7 +321,15 @@ unsigned long randomize_stack_top(unsigned long stack_top) } #ifdef CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT -#ifdef CONFIG_ARCH_HAS_ELF_RANDOMIZE +unsigned long arch_randomize_brk(struct mm_struct *mm) +{ + /* Is the current task 32bit ? */ + if (!IS_ENABLED(CONFIG_64BIT) || is_compat_task()) + return randomize_page(mm->brk, SZ_32M); + + return randomize_page(mm->brk, SZ_1G); +} + unsigned long arch_mmap_rnd(void) { unsigned long rnd; @@ -335,7 +343,6 @@ unsigned long arch_mmap_rnd(void) return rnd << PAGE_SHIFT; } -#endif /* CONFIG_ARCH_HAS_ELF_RANDOMIZE */ static int mmap_is_legacy(struct rlimit *rlim_stack) {