From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752804AbaHRJfK (ORCPT ); Mon, 18 Aug 2014 05:35:10 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:42780 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752753AbaHRJfE (ORCPT ); Mon, 18 Aug 2014 05:35:04 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Martin Schwidefsky , Ben Hutchings , Luis Henriques Subject: [PATCH 3.11 069/137] s390/ptrace: fix PSW mask check Date: Mon, 18 Aug 2014 10:32:10 +0100 Message-Id: <1408354398-10226-70-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1408354398-10226-1-git-send-email-luis.henriques@canonical.com> References: <1408354398-10226-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.11 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.11.10.15 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Martin Schwidefsky commit dab6cf55f81a6e16b8147aed9a843e1691dcd318 upstream. The PSW mask check of the PTRACE_POKEUSR_AREA command is incorrect. For the default user_mode=home address space layout the psw_user_bits variable has the home space address-space-control bits set. But the PSW_MASK_USER contains PSW_MASK_ASC, the ptrace validity check for the PSW mask will therefore always fail. Fixes CVE-2014-3534 Signed-off-by: Martin Schwidefsky Cc: Ben Hutchings [ luis: backported to 3.11: used Martin's backport to 3.2 ] Signed-off-by: Luis Henriques --- arch/s390/kernel/ptrace.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c index e9fadb04e3c6..319da563e6cf 100644 --- a/arch/s390/kernel/ptrace.c +++ b/arch/s390/kernel/ptrace.c @@ -322,7 +322,9 @@ static int __poke_user(struct task_struct *child, addr_t addr, addr_t data) * psw and gprs are stored on the stack */ if (addr == (addr_t) &dummy->regs.psw.mask && - ((data & ~PSW_MASK_USER) != psw_user_bits || + (((data^psw_user_bits) & ~PSW_MASK_USER) || + (((data^psw_user_bits) & PSW_MASK_ASC) && + ((data|psw_user_bits) & PSW_MASK_ASC) == PSW_MASK_ASC) || ((data & PSW_MASK_EA) && !(data & PSW_MASK_BA)))) /* Invalid psw mask. */ return -EINVAL; @@ -655,7 +657,10 @@ static int __poke_user_compat(struct task_struct *child, */ if (addr == (addr_t) &dummy32->regs.psw.mask) { /* Build a 64 bit psw mask from 31 bit mask. */ - if ((tmp & ~PSW32_MASK_USER) != psw32_user_bits) + if (((tmp^psw32_user_bits) & ~PSW32_MASK_USER) || + (((tmp^psw32_user_bits) & PSW32_MASK_ASC) && + ((tmp|psw32_user_bits) & PSW32_MASK_ASC) + == PSW32_MASK_ASC)) /* Invalid psw mask. */ return -EINVAL; regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) | -- 1.9.1