From patchwork Wed Mar 4 02:10:19 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 446016 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 421CD1401DD for ; Wed, 4 Mar 2015 13:23:07 +1100 (AEDT) Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 201701A0DBD for ; Wed, 4 Mar 2015 13:23:07 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from smtp.outflux.net (smtp.outflux.net [IPv6:2001:19d0:2:6:c0de:0:736d:7470]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 9977D1A0C71 for ; Wed, 4 Mar 2015 13:14:37 +1100 (AEDT) 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 t242ATC8002268; Tue, 3 Mar 2015 18:10:29 -0800 From: Kees Cook To: akpm@linux-foundation.org Subject: [PATCH v3 04/10] mips: extract logic for mmap_rnd() Date: Tue, 3 Mar 2015 18:10:19 -0800 Message-Id: <1425435025-30284-5-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 Cc: linux-mips@linux-mips.org, Arun Chandran , Catalin Marinas , Heiko Carstens , Oleg Nesterov , Min-Hua Chen , Paul Mackerras , Ismael Ripoll , Yann Droneaud , linux-s390@vger.kernel.org, Russell King , Andrey Ryabinin , Behan Webster , x86@kernel.org, Hector Marco-Gisbert , "David A. Long" , Ben Hutchings , Kees Cook , Will Deacon , linux-fsdevel@vger.kernel.org, Alexander Viro , Dan McGee , Michael Holzheu , linux-arm-kernel@lists.infradead.org, Jeff Bailey , Paul Burton , linux-kernel@vger.kernel.org, Ralf Baechle , Andy Lutomirski , Vineeth Vijayan , Markos Chandras , =?UTF-8?q?Jan-Simon=20M=C3=B6ller?= , Martin Schwidefsky , linux390@de.ibm.com, linuxppc-dev@lists.ozlabs.org, Alex Smith X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" In preparation for splitting out ET_DYN ASLR, extract the mmap ASLR selection into a separate function. Signed-off-by: Kees Cook --- arch/mips/mm/mmap.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c index f1baadd56e82..673a5cfe082f 100644 --- a/arch/mips/mm/mmap.c +++ b/arch/mips/mm/mmap.c @@ -142,18 +142,26 @@ unsigned long arch_get_unmapped_area_topdown(struct file *filp, addr0, len, pgoff, flags, DOWN); } +static unsigned long mmap_rnd(void) +{ + unsigned long rnd; + + rnd = (unsigned long)get_random_int(); + rnd <<= PAGE_SHIFT; + if (TASK_IS_32BIT_ADDR) + random_factor &= 0xfffffful; + else + random_factor &= 0xffffffful; + + return rnd; +} + void arch_pick_mmap_layout(struct mm_struct *mm) { unsigned long random_factor = 0UL; - if (current->flags & PF_RANDOMIZE) { - random_factor = get_random_int(); - random_factor = random_factor << PAGE_SHIFT; - if (TASK_IS_32BIT_ADDR) - random_factor &= 0xfffffful; - else - random_factor &= 0xffffffful; - } + if (current->flags & PF_RANDOMIZE) + random_factor = mmap_rnd(); if (mmap_is_legacy()) { mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;