From patchwork Thu May 28 10:56:49 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 6497371 Return-Path: X-Original-To: patchwork-linux-parisc@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 5B86C9F38D for ; Thu, 28 May 2015 10:56:55 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5BFE920612 for ; Thu, 28 May 2015 10:56:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3471D2060B for ; Thu, 28 May 2015 10:56:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753279AbbE1K4w (ORCPT ); Thu, 28 May 2015 06:56:52 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:47051 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752810AbbE1K4v (ORCPT ); Thu, 28 May 2015 06:56:51 -0400 Received: from [10.172.192.212] (helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1YxvUX-0002W7-S8; Thu, 28 May 2015 10:56:49 +0000 From: Luis Henriques To: Helge Deller Cc: linux-parisc@vger.kernel.org, James Hogan , linux-metag@vger.kernel.org, Luis Henriques , kernel-team@lists.ubuntu.com Subject: [3.16.y-ckt stable] Patch "parisc, metag: Fix crashes due to stack randomization on stack-grows-upwards architectures" has been added to staging queue Date: Thu, 28 May 2015 11:56:49 +0100 Message-Id: <1432810609-24332-1-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 X-Extended-Stable: 3.16 Sender: linux-parisc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_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-3.16.y-queue branch of the 3.16.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue This patch is scheduled to be released in version 3.16.7-ckt13. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.16.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From 441b34775e8375194ce741e53f0e19241749ef35 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: Luis Henriques --- arch/parisc/include/asm/elf.h | 4 ++++ arch/parisc/kernel/sys_parisc.c | 3 +++ fs/exec.c | 3 +++ 3 files changed, 10 insertions(+) -- 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 3391d061eccc..78c9fd32c554 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 e1ffea2f9a0b..5aba01ac457f 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 68a0843250c9..993ed0aba99a 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -662,6 +662,9 @@ 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;