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=-3.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 86883C2BA19 for ; Mon, 6 Apr 2020 13:01:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4C4D622252 for ; Mon, 6 Apr 2020 13:01:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="bkPu4imx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728256AbgDFNB4 (ORCPT ); Mon, 6 Apr 2020 09:01:56 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:60140 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728061AbgDFNB4 (ORCPT ); Mon, 6 Apr 2020 09:01:56 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=zNFwdM697I69ZxsCtjPZ0n5v/OJG96sZh4pg4CmQykg=; b=bkPu4imxbhFePpIISA5dVVI3ve hrQewkOpY2Kuo+k2IrrOwjR5jq8r9+N9osdPKRIfENFy0m4qW0bvFozgCbfDlXhUkal2InBY+EK75 i3LGusKTGbjzZ7R7/IIetY/CgF4NPThI4Zu91d0NJj8m279Qr4YQbCvDdnHNQPATYu2pfZB8E1NQq Jy4X30m9gCugOuVgHUxi4EgZ4rkJDMheCEzCgQtabp7YoOAOYOKqTmzeIV4vWXoxyOhDVJX5lF3uV qIklpFRsBvRPbd4t73fj3Vsl8gXb/0H5sYeVcNWd1QjPuVtWwXCNp7gV7dgIzk82n+5uHmlRQMeCN jXx0rbMA==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jLRNz-000587-1y; Mon, 06 Apr 2020 13:01:55 +0000 Date: Mon, 6 Apr 2020 06:01:55 -0700 From: Christoph Hellwig To: Peter Zijlstra Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, jroedel@suse.de, vbabka@suse.cz, urezki@gmail.com, Thomas Gleixner , Olof Johansson , Sakari Ailus , Mauro Carvalho Chehab Subject: Re: [PATCH] mm/vmalloc: Sanitize __get_vm_area() arguments Message-ID: <20200406130155.GB29306@infradead.org> References: <20200403163253.GU20730@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200403163253.GU20730@hirez.programming.kicks-ass.net> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 03, 2020 at 06:32:53PM +0200, Peter Zijlstra wrote: > > __get_vm_area() is an exported symbol, make sure the callers stay in > the expected memory range. When calling this function with memory > ranges outside of the VMALLOC range *bad* things can happen. > > (I noticed this when I managed to corrupt the kernel text by accident) Maybe it is time to unexport it? There are only two users: - staging/media/ipu3 really should be using vmap. And given that it is a staging driver it really doesn't matter anyway if we break it. - pcmcia/electra_cf.c is actually using it for something that is not a vmalloc address. But it is so special that I think prohibiting to build it as module seems fine. > > Signed-off-by: Peter Zijlstra (Intel) > --- > mm/vmalloc.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -2130,6 +2130,13 @@ static struct vm_struct *__get_vm_area_n > struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags, > unsigned long start, unsigned long end) > { > + /* > + * Ensure callers stay in the vmalloc range. > + */ > + if (WARN_ON(start < VMALLOC_START || start > VMALLOC_END || > + end < VMALLOC_START || end > VMALLOC_END)) > + return NULL; > + > return __get_vm_area_node(size, 1, flags, start, end, NUMA_NO_NODE, > GFP_KERNEL, __builtin_return_address(0)); > } ---end quoted text---