From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752709AbbCDVOp (ORCPT ); Wed, 4 Mar 2015 16:14:45 -0500 Received: from smtp.outflux.net ([198.145.64.163]:56448 "EHLO smtp.outflux.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751910AbbCDVOm (ORCPT ); Wed, 4 Mar 2015 16:14:42 -0500 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 01/10] arm: factor out mmap ASLR into mmap_rnd Date: Wed, 4 Mar 2015 13:10:45 -0800 Message-Id: <1425503454-7531-2-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-HELO: www.outflux.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In preparation for splitting out ET_DYN ASLR, this moves the ASLR calculations for mmap on ARM into a separate routine, similar to x86. This also removes the redundant check of personality (PF_RANDOMIZE is already set before calling arch_pick_mmap_layout). Signed-off-by: Kees Cook --- arch/arm/mm/mmap.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c index 5e85ed371364..15a8160096b3 100644 --- a/arch/arm/mm/mmap.c +++ b/arch/arm/mm/mmap.c @@ -169,14 +169,22 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, return addr; } +static unsigned long mmap_rnd(void) +{ + unsigned long rnd; + + /* 8 bits of randomness in 20 address space bits */ + rnd = (unsigned long)get_random_int() % (1 << 8); + + return rnd << PAGE_SHIFT; +} + void arch_pick_mmap_layout(struct mm_struct *mm) { unsigned long random_factor = 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; + if (current->flags & PF_RANDOMIZE) + random_factor = mmap_rnd(); if (mmap_is_legacy()) { mm->mmap_base = TASK_UNMAPPED_BASE + random_factor; -- 1.9.1