From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5E874C54FCC for ; Mon, 20 Apr 2020 22:33:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 39F9220B1F for ; Mon, 20 Apr 2020 22:33:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587422034; bh=ViONWUUyMBUwXsCi2iskcpvlAwUnt1s05iWjG3WH8Pw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=fPd4lqE4OeQPnxwcbmgzpAyUmqexhCU3i/fF5b17s+NpE9veBnqEYl2dhAm5+2Uv3 ixGl5jlFjhzTzj1r7+PrKEBqclYxMEKgo8dxRNm6ECry/R2r+2UdfI82VZcF9HhzPQ ufPPL3+h9iJs80hZxQTDzxn3s4U9dJ4mx9BCvJZo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728209AbgDTWdx (ORCPT ); Mon, 20 Apr 2020 18:33:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:50652 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726362AbgDTWdx (ORCPT ); Mon, 20 Apr 2020 18:33:53 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7C24F20782; Mon, 20 Apr 2020 22:33:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587422032; bh=ViONWUUyMBUwXsCi2iskcpvlAwUnt1s05iWjG3WH8Pw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=uDwWm7NxumBoTt+V8rV7xTtd1DxB+bFx9ihDXHb5kZqYopJHQgVgv8cAMvuSUqhnS FVS1nKe//wXkKusDiwWiaObhZli1SvY6fERQPqRdGARnYi7sLQbizUt/zhSKkNZEum Yo9Cjpi80RTrd2r5cBHttRMh9pz+VL7u6GiIRaAc= Date: Mon, 20 Apr 2020 15:33:52 -0700 From: Andrew Morton To: glider@google.com Cc: adobriyan@gmail.com, linux-kernel@vger.kernel.org, sunhaoyl@outlook.com, Kees Cook Subject: Re: [PATCH] fs/binfmt_elf.c: allocate initialized memory in fill_thread_core_info() Message-Id: <20200420153352.6682533e794f591dae7aafbc@linux-foundation.org> In-Reply-To: <20200419100848.63472-1-glider@google.com> References: <20200419100848.63472-1-glider@google.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 19 Apr 2020 12:08:48 +0200 glider@google.com wrote: > KMSAN reported uninitialized data being written to disk when dumping > core. As a result, several kilobytes of kmalloc memory may be written to > the core file and then read by a non-privileged user. > > ... > > --- a/fs/binfmt_elf.c > +++ b/fs/binfmt_elf.c > @@ -1733,7 +1733,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t, > (!regset->active || regset->active(t->task, regset) > 0)) { > int ret; > size_t size = regset_size(t->task, regset); > - void *data = kmalloc(size, GFP_KERNEL); > + void *data = kzalloc(size, GFP_KERNEL); > if (unlikely(!data)) > return 0; > ret = regset->get(t->task, regset, This seems to be a quite easy way of exposing quite a large amount of kernel memory contents, so I think I'll add a cc:stable to this patch?