From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754920AbaG3Btg (ORCPT ); Tue, 29 Jul 2014 21:49:36 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:60440 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754855AbaG3Bte (ORCPT ); Tue, 29 Jul 2014 21:49:34 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Martin Schwidefsky , Ben Hutchings Subject: [PATCH 3.10 19/21] s390/ptrace: fix PSW mask check Date: Tue, 29 Jul 2014 18:48:48 -0700 Message-Id: <20140730014831.284017694@linuxfoundation.org> X-Mailer: git-send-email 2.0.3 In-Reply-To: <20140730014830.424826215@linuxfoundation.org> References: <20140730014830.424826215@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.10-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. The PSW_MASK_USER define contains the PSW_MASK_ASC bits, the ptrace interface accepts all combinations for the address-space-control bits. To protect the kernel space the PSW mask check in ptrace needs to reject the address-space-control bit combination for home space. Fixes CVE-2014-3534 Signed-off-by: Martin Schwidefsky Cc: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- arch/s390/kernel/ptrace.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/arch/s390/kernel/ptrace.c +++ b/arch/s390/kernel/ptrace.c @@ -314,7 +314,9 @@ static int __poke_user(struct task_struc * 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; @@ -627,7 +629,10 @@ static int __poke_user_compat(struct tas */ 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) |