From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754550AbbCCAVk (ORCPT ); Mon, 2 Mar 2015 19:21:40 -0500 Received: from smtp.outflux.net ([198.145.64.163]:58702 "EHLO smtp.outflux.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754110AbbCCAVi (ORCPT ); Mon, 2 Mar 2015 19:21:38 -0500 From: Kees Cook To: akpm@linux-foundation.org Cc: Kees Cook , linux-kernel@vger.kernel.org, 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 , Yann Droneaud , Min-Hua Chen , Paul Burton , Alex Smith , Markos Chandras , Jeff Bailey , Vineeth Vijayan , Michael Holzheu , Ben Hutchings , Hector Marco-Gisbert , Borislav Petkov , =?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 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-HELO: www.outflux.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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; -- 1.9.1