From patchwork Tue Mar 3 00:19:44 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 445504 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 B845814010F for ; Tue, 3 Mar 2015 11:22:10 +1100 (AEDT) Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 93DFC1A075A for ; Tue, 3 Mar 2015 11:22:10 +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 634921A01E7 for ; Tue, 3 Mar 2015 11:21:08 +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 t230JrqE011891; Mon, 2 Mar 2015 16:19:53 -0800 From: Kees Cook To: akpm@linux-foundation.org Subject: [PATCH 1/5] arm: factor out mmap ASLR into mmap_rnd Date: Mon, 2 Mar 2015 16:19:44 -0800 Message-Id: <1425341988-1599-2-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1425341988-1599-1-git-send-email-keescook@chromium.org> References: <1425341988-1599-1-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 , Yann Droneaud , linux-s390@vger.kernel.org, Russell King , Andrey Ryabinin , x86@kernel.org, Hector Marco-Gisbert , "David A. Long" , Borislav Petkov , Ben Hutchings , Kees Cook , Will Deacon , linux-fsdevel@vger.kernel.org, Alexander Viro , 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 exporting per-arch mmap randomization functions, this moves the ASLR calculations for mmap on ARM into a separate routine. Signed-off-by: Kees Cook Acked-by: Russell King --- arch/arm/mm/mmap.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c index 5e85ed371364..0f8bc158f2c6 100644 --- a/arch/arm/mm/mmap.c +++ b/arch/arm/mm/mmap.c @@ -169,14 +169,21 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, return addr; } -void arch_pick_mmap_layout(struct mm_struct *mm) +static unsigned long mmap_rnd(void) { - unsigned long random_factor = 0UL; + unsigned long rnd = 0UL; /* 8 bits of randomness in 20 address space bits */ if ((current->flags & PF_RANDOMIZE) && !(current->personality & ADDR_NO_RANDOMIZE)) - random_factor = (get_random_int() % (1 << 8)) << PAGE_SHIFT; + rnd = (get_random_int() % (1 << 8)) << PAGE_SHIFT; + + return rnd; +} + +void arch_pick_mmap_layout(struct mm_struct *mm) +{ + unsigned long random_factor = mmap_rnd(); if (mmap_is_legacy()) { mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;