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=-13.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 DCE87CA9EAF for ; Wed, 30 Oct 2019 09:18:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AF7CA2087E for ; Wed, 30 Oct 2019 09:18:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572427134; bh=l0MLxBZudc4uU+Zxyk/+94yM1uRPca1KLUiWb6F2o58=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Z0me71v+uFiN6bFRbz5bTEEgSmCk8k3DmITB9bYVr4YKwTcnTg8U1Pa7xBG3zYeB4 tKxkK2KRVRI5kFIEWUy8DAyrC64tA4atRsGeVXXo5Bfm8c7qCPVqkhVnGDAPC1TlJt 0SUbo9x330GgHCRZc+A9O4PlvxzzrwX51gqnV7u4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726268AbfJ3JSx (ORCPT ); Wed, 30 Oct 2019 05:18:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:39204 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726028AbfJ3JSx (ORCPT ); Wed, 30 Oct 2019 05:18:53 -0400 Received: from localhost (unknown [91.217.168.176]) (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 C9C35205ED; Wed, 30 Oct 2019 09:18:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572427132; bh=l0MLxBZudc4uU+Zxyk/+94yM1uRPca1KLUiWb6F2o58=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=2PfK0xiKm+k8UGwS7o+AjImlguwO/u1yygHJq2jWEkrnR2I7gKWoYyd21R9E1ZTOS kzo/VJaajX15U/EN/K+CsybbiwRRr0ynjwi885L7Lv4l3W/96gnfDy9SC/bOD3vsUA xrADAi7umiQKJMjunQZzIbjjCZQ25qTEmxZUGJKo= Date: Wed, 30 Oct 2019 10:18:49 +0100 From: Greg Kroah-Hartman To: Kees Cook Cc: Christoph Hellwig , Robin Murphy , Laura Abbott , Marek Szyprowski , Jesper Dangaard Brouer , Allison Randal , Thomas Gleixner , Stephen Boyd , Dan Carpenter , Semmle Security Reports , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 1/2] dma-mapping: Add vmap checks to dma_map_single() Message-ID: <20191030091849.GA637042@kroah.com> References: <20191029213423.28949-1-keescook@chromium.org> <20191029213423.28949-2-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191029213423.28949-2-keescook@chromium.org> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 29, 2019 at 02:34:22PM -0700, Kees Cook wrote: > As we've seen from USB and other areas[1], we need to always do runtime > checks for DMA operating on memory regions that might be remapped. This > adds vmap checks (similar to those already in USB but missing in other > places) into dma_map_single() so all callers benefit from the checking. > > [1] https://git.kernel.org/linus/3840c5b78803b2b6cc1ff820100a74a092c40cbb > > Suggested-by: Laura Abbott > Signed-off-by: Kees Cook > --- > include/linux/dma-mapping.h | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h > index 4a1c4fca475a..54de3c496407 100644 > --- a/include/linux/dma-mapping.h > +++ b/include/linux/dma-mapping.h > @@ -583,6 +583,12 @@ static inline unsigned long dma_get_merge_boundary(struct device *dev) > static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr, > size_t size, enum dma_data_direction dir, unsigned long attrs) > { > + /* DMA must never operate on areas that might be remapped. */ > + if (dev_WARN_ONCE(dev, is_vmalloc_addr(ptr), > + "wanted %zu bytes mapped in vmalloc\n", size)) { > + return DMA_MAPPING_ERROR; > + } That's a very odd error string, I know if I saw it for the first time, I would have no idea what it meant. The USB message at least gives you a bit more context as to what went wrong and how to fix it. How about something like "Memory is not DMA capabable, please fix the allocation of it to be correct", or "non-dma-able memory was attempted to be mapped, but this is impossible to to" or something else. thanks, greg k-h