From patchwork Wed Mar 4 21:10:47 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 5940431 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id C53E7BF440 for ; Wed, 4 Mar 2015 21:13:20 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id D6DFA2035B for ; Wed, 4 Mar 2015 21:13:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA4FA20320 for ; Wed, 4 Mar 2015 21:13:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752162AbbCDVNI (ORCPT ); Wed, 4 Mar 2015 16:13:08 -0500 Received: from smtp.outflux.net ([198.145.64.163]:34177 "EHLO smtp.outflux.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751360AbbCDVNF (ORCPT ); Wed, 4 Mar 2015 16:13:05 -0500 Received: from www.outflux.net (serenity.outflux.net [10.2.0.2]) by vinyl.outflux.net (8.14.4/8.14.4/Debian-4.1ubuntu1) with ESMTP id t24LAuDS020852; Wed, 4 Mar 2015 13:10:56 -0800 From: Kees Cook To: akpm@linux-foundation.org Cc: Kees Cook , Ingo Molnar , Michael Ellerman , Hector Marco-Gisbert , Ismael Ripoll , Russell King , Catalin Marinas , Will Deacon , Ralf Baechle , Benjamin Herrenschmidt , Paul Mackerras , Martin Schwidefsky , Heiko Carstens , linux390@de.ibm.com, x86@kernel.org, Alexander Viro , Andy Lutomirski , Oleg Nesterov , "David A. Long" , Andrey Ryabinin , Arun Chandran , Yann Droneaud , Min-Hua Chen , Paul Burton , Alex Smith , Markos Chandras , Vineeth Vijayan , Jeff Bailey , Michael Holzheu , Ben Hutchings , Borislav Petkov , =?UTF-8?q?Jan-Simon=20M=C3=B6ller?= , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@linux-mips.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH v4 03/10] arm64: standardize mmap_rnd() usage Date: Wed, 4 Mar 2015 13:10:47 -0800 Message-Id: <1425503454-7531-4-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1425503454-7531-1-git-send-email-keescook@chromium.org> References: <1425503454-7531-1-git-send-email-keescook@chromium.org> X-MIMEDefang-Filter: outflux$Revision: 1.316 $ X-HELO: www.outflux.net X-Scanned-By: MIMEDefang 2.73 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In preparation for splitting out ET_DYN ASLR, this refactors the use of mmap_rnd() to be used similarly to arm and x86. This additionally enables mmap ASLR on legacy mmap layouts, which appeared to be missing on arm64, and was already supported on arm. Additionally removes a copy/pasted declaration of an unused function. Signed-off-by: Kees Cook --- arch/arm64/include/asm/elf.h | 1 - arch/arm64/mm/mmap.c | 18 +++++++++++------- 2 files changed, 11 insertions(+), 8 deletions(-) diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h index 1f65be393139..f724db00b235 100644 --- a/arch/arm64/include/asm/elf.h +++ b/arch/arm64/include/asm/elf.h @@ -125,7 +125,6 @@ typedef struct user_fpsimd_state elf_fpregset_t; * 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. */ -extern unsigned long randomize_et_dyn(unsigned long base); #define ELF_ET_DYN_BASE (2 * TASK_SIZE_64 / 3) /* diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c index 54922d1275b8..ba776c01b552 100644 --- a/arch/arm64/mm/mmap.c +++ b/arch/arm64/mm/mmap.c @@ -49,15 +49,14 @@ static int mmap_is_legacy(void) static unsigned long mmap_rnd(void) { - unsigned long rnd = 0; + unsigned long rnd; - if (current->flags & PF_RANDOMIZE) - rnd = (long)get_random_int() & STACK_RND_MASK; + rnd = (unsigned long)get_random_int() & STACK_RND_MASK; return rnd << PAGE_SHIFT; } -static unsigned long mmap_base(void) +static unsigned long mmap_base(unsigned long rnd) { unsigned long gap = rlimit(RLIMIT_STACK); @@ -66,7 +65,7 @@ static unsigned long mmap_base(void) else if (gap > MAX_GAP) gap = MAX_GAP; - return PAGE_ALIGN(STACK_TOP - gap - mmap_rnd()); + return PAGE_ALIGN(STACK_TOP - gap - rnd); } /* @@ -75,15 +74,20 @@ static unsigned long mmap_base(void) */ void arch_pick_mmap_layout(struct mm_struct *mm) { + unsigned long random_factor = 0UL; + + if (current->flags & PF_RANDOMIZE) + random_factor = mmap_rnd(); + /* * Fall back to the standard layout if the personality bit is set, or * if the expected stack growth is unlimited: */ if (mmap_is_legacy()) { - mm->mmap_base = TASK_UNMAPPED_BASE; + mm->mmap_base = TASK_UNMAPPED_BASE + random_factor; mm->get_unmapped_area = arch_get_unmapped_area; } else { - mm->mmap_base = mmap_base(); + mm->mmap_base = mmap_base(random_factor); mm->get_unmapped_area = arch_get_unmapped_area_topdown; } }