From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753593Ab1GHS1M (ORCPT ); Fri, 8 Jul 2011 14:27:12 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:40289 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751811Ab1GHS1L (ORCPT ); Fri, 8 Jul 2011 14:27:11 -0400 Date: Fri, 8 Jul 2011 11:27:06 -0700 From: Andrew Morton To: Dan Rosenberg Cc: chris@zankel.net, security@kernel.org, linux-kernel@vger.kernel.org, Oleg Nesterov Subject: Re: [Security] [PATCH] xtensa: prevent arbitrary read in ptrace Message-Id: <20110708112706.9014d306.akpm@linux-foundation.org> In-Reply-To: <1310083434.2139.4.camel@anubis> References: <1310083434.2139.4.camel@anubis> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 07 Jul 2011 20:03:54 -0400 Dan Rosenberg wrote: > Prevent an arbitrary kernel read. Check the user pointer with > access_ok() before copying data in. > > Signed-off-by: Dan Rosenberg > Cc: stable@kernel.org > --- > arch/xtensa/kernel/ptrace.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/arch/xtensa/kernel/ptrace.c b/arch/xtensa/kernel/ptrace.c > index c72c947..ddce75e 100644 > --- a/arch/xtensa/kernel/ptrace.c > +++ b/arch/xtensa/kernel/ptrace.c > @@ -147,6 +147,9 @@ int ptrace_setxregs(struct task_struct *child, void __user *uregs) > elf_xtregs_t *xtregs = uregs; > int ret = 0; > > + if (!access_ok(VERIFY_READ, uregs, sizeof(elf_xtregs_t))) > + return -EIO; This should be -EFAULT, methinks? > + > #if XTENSA_HAVE_COPROCESSORS > /* Flush all coprocessors before we overwrite them. */ > coprocessor_flush_all(ti);