From patchwork Tue Jun 16 00:22:26 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 6612571 Return-Path: X-Original-To: patchwork-linux-parisc@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 6EEAEC0020 for ; Tue, 16 Jun 2015 00:22:35 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 6B092207D1 for ; Tue, 16 Jun 2015 00:22:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 321A9207B1 for ; Tue, 16 Jun 2015 00:22:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751392AbbFPAWc (ORCPT ); Mon, 15 Jun 2015 20:22:32 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:40959 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751864AbbFPAWb (ORCPT ); Mon, 15 Jun 2015 20:22:31 -0400 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1Z4ee4-0005NN-VF; Tue, 16 Jun 2015 00:22:29 +0000 Received: from kamal by fourier with local (Exim 4.82) (envelope-from ) id 1Z4ee2-00042m-Nn; Mon, 15 Jun 2015 17:22:26 -0700 From: Kamal Mostafa To: Helge Deller Cc: linux-parisc@vger.kernel.org, James Hogan , linux-metag@vger.kernel.org, Kamal Mostafa , kernel-team@lists.ubuntu.com Subject: [3.19.y-ckt stable] Patch "parisc, metag: Fix crashes due to stack randomization on stack-grows-upwards architectures" has been added to staging queue Date: Mon, 15 Jun 2015 17:22:26 -0700 Message-Id: <1434414146-15514-1-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 X-Extended-Stable: 3.19 Sender: linux-parisc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org X-Spam-Status: No, score=-7.4 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, 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 This is a note to let you know that I have just added a patch titled parisc,metag: Fix crashes due to stack randomization on stack-grows-upwards architectures to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue This patch is scheduled to be released in version 3.19.8-ckt2. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.19.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 264f3887a1df6bf17f366be430441c9b8728dd89 Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Mon, 11 May 2015 22:01:27 +0200 Subject: parisc,metag: Fix crashes due to stack randomization on stack-grows-upwards architectures commit d045c77c1a69703143a36169c224429c48b9eecd upstream. On architectures where the stack grows upwards (CONFIG_STACK_GROWSUP=y, currently parisc and metag only) stack randomization sometimes leads to crashes when the stack ulimit is set to lower values than STACK_RND_MASK (which is 8 MB by default if not defined in arch-specific headers). The problem is, that when the stack vm_area_struct is set up in fs/exec.c, the additional space needed for the stack randomization (as defined by the value of STACK_RND_MASK) was not taken into account yet and as such, when the stack randomization code added a random offset to the stack start, the stack effectively got smaller than what the user defined via rlimit_max(RLIMIT_STACK) which then sometimes leads to out-of-stack situations and crashes. This patch fixes it by adding the maximum possible amount of memory (based on STACK_RND_MASK) which theoretically could be added by the stack randomization code to the initial stack size. That way, the user-defined stack size is always guaranteed to be at minimum what is defined via rlimit_max(RLIMIT_STACK). This bug is currently not visible on the metag architecture, because on metag STACK_RND_MASK is defined to 0 which effectively disables stack randomization. The changes to fs/exec.c are inside an "#ifdef CONFIG_STACK_GROWSUP" section, so it does not affect other platformws beside those where the stack grows upwards (parisc and metag). Signed-off-by: Helge Deller Cc: linux-parisc@vger.kernel.org Cc: James Hogan Cc: linux-metag@vger.kernel.org Signed-off-by: Kamal Mostafa --- arch/parisc/include/asm/elf.h | 4 ++++ arch/parisc/kernel/sys_parisc.c | 3 +++ fs/exec.c | 3 +++ 3 files changed, 10 insertions(+) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/parisc/include/asm/elf.h b/arch/parisc/include/asm/elf.h index 3391d06..78c9fd3 100644 --- a/arch/parisc/include/asm/elf.h +++ b/arch/parisc/include/asm/elf.h @@ -348,6 +348,10 @@ struct pt_regs; /* forward declaration... */ #define ELF_HWCAP 0 +#define STACK_RND_MASK (is_32bit_task() ? \ + 0x7ff >> (PAGE_SHIFT - 12) : \ + 0x3ffff >> (PAGE_SHIFT - 12)) + struct mm_struct; extern unsigned long arch_randomize_brk(struct mm_struct *); #define arch_randomize_brk arch_randomize_brk diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c index e1ffea2..5aba01a 100644 --- a/arch/parisc/kernel/sys_parisc.c +++ b/arch/parisc/kernel/sys_parisc.c @@ -77,6 +77,9 @@ static unsigned long mmap_upper_limit(void) if (stack_base > STACK_SIZE_MAX) stack_base = STACK_SIZE_MAX; + /* Add space for stack randomization. */ + stack_base += (STACK_RND_MASK << PAGE_SHIFT); + return PAGE_ALIGN(STACK_TOP - stack_base); } diff --git a/fs/exec.c b/fs/exec.c index 4617a4e..be18722 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -659,6 +659,9 @@ int setup_arg_pages(struct linux_binprm *bprm, if (stack_base > STACK_SIZE_MAX) stack_base = STACK_SIZE_MAX; + /* Add space for stack randomization. */ + stack_base += (STACK_RND_MASK << PAGE_SHIFT); + /* Make sure we didn't let the argument array grow too large. */ if (vma->vm_end - vma->vm_start > stack_base) return -ENOMEM;