From patchwork Wed Mar 4 02:10:21 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 5928221 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 22131BF440 for ; Wed, 4 Mar 2015 02:31:47 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5B5AA2034A for ; Wed, 4 Mar 2015 02:31:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 69BFB20260 for ; Wed, 4 Mar 2015 02:31:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757973AbbCDCax (ORCPT ); Tue, 3 Mar 2015 21:30:53 -0500 Received: from smtp.outflux.net ([198.145.64.163]:54847 "EHLO smtp.outflux.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757941AbbCDCav (ORCPT ); Tue, 3 Mar 2015 21:30:51 -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 t242AbLH002303; Tue, 3 Mar 2015 18:10:37 -0800 From: Kees Cook To: akpm@linux-foundation.org Cc: Kees Cook , linux-kernel@vger.kernel.org, Hector Marco-Gisbert , Ismael Ripoll , Russell King , Catalin Marinas , Will Deacon , Ralf Baechle , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Martin Schwidefsky , Heiko Carstens , linux390@de.ibm.com, x86@kernel.org, Alexander Viro , Oleg Nesterov , Andy Lutomirski , "David A. Long" , Andrey Ryabinin , Arun Chandran , Min-Hua Chen , Dan McGee , Yann Droneaud , Paul Burton , Alex Smith , Markos Chandras , Vineeth Vijayan , Jeff Bailey , Michael Holzheu , Ben Hutchings , Behan Webster , =?UTF-8?q?Jan-Simon=20M=C3=B6ller?= , 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 v3 06/10] s390: standardize mmap_rnd() usage Date: Tue, 3 Mar 2015 18:10:21 -0800 Message-Id: <1425435025-30284-7-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1425435025-30284-1-git-send-email-keescook@chromium.org> References: <1425435025-30284-1-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, and extracts the checking of PF_RANDOMIZE. Signed-off-by: Kees Cook --- arch/s390/mm/mmap.c | 34 +++++++++++++++++++++++----------- 1 file changed, 23 insertions(+), 11 deletions(-) diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c index 179a2c20b01f..db57078075c5 100644 --- a/arch/s390/mm/mmap.c +++ b/arch/s390/mm/mmap.c @@ -62,20 +62,18 @@ static inline int mmap_is_legacy(void) static unsigned long mmap_rnd(void) { - if (!(current->flags & PF_RANDOMIZE)) - return 0; if (is_32bit_task()) return (get_random_int() & 0x7ff) << PAGE_SHIFT; else return (get_random_int() & mmap_rnd_mask) << PAGE_SHIFT; } -static unsigned long mmap_base_legacy(void) +static unsigned long mmap_base_legacy(unsigned long rnd) { - return TASK_UNMAPPED_BASE + mmap_rnd(); + return TASK_UNMAPPED_BASE + rnd; } -static inline unsigned long mmap_base(void) +static inline unsigned long mmap_base(unsigned long rnd) { unsigned long gap = rlimit(RLIMIT_STACK); @@ -84,7 +82,7 @@ static inline unsigned long mmap_base(void) else if (gap > MAX_GAP) gap = MAX_GAP; gap &= PAGE_MASK; - return STACK_TOP - stack_maxrandom_size() - mmap_rnd() - gap; + return STACK_TOP - stack_maxrandom_size() - rnd - gap; } unsigned long @@ -187,7 +185,11 @@ unsigned long randomize_et_dyn(void) if (!is_32bit_task()) /* Align to 4GB */ base &= ~((1UL << 32) - 1); - return base + mmap_rnd(); + + if (current->flags & PF_RANDOMIZE) + base += mmap_rnd(); + + return base; } #ifndef CONFIG_64BIT @@ -198,15 +200,20 @@ unsigned long randomize_et_dyn(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 = mmap_base_legacy(); + mm->mmap_base = mmap_base_legacy(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; } } @@ -273,15 +280,20 @@ s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr, */ 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 = mmap_base_legacy(); + mm->mmap_base = mmap_base_legacy(random_factor); mm->get_unmapped_area = s390_get_unmapped_area; } else { - mm->mmap_base = mmap_base(); + mm->mmap_base = mmap_base(random_factor); mm->get_unmapped_area = s390_get_unmapped_area_topdown; } }