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,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 A7ABBC47E49 for ; Wed, 30 Oct 2019 19:26:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7B6C120650 for ; Wed, 30 Oct 2019 19:26:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572463605; bh=oZdsRq9DtlyqOY59UsuqYnw0hffYd6itQ5//OM9N0yo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=kEvHo+CMhK1TAdAycdG7NHbfnHMBXnqcvhOShJaAxLtRd3Azt9+ZsZMv8zpWie40m xfqwuFVSLpgrK0LVczAPh9DyJ9w4PzK91qfYB34hRDCrgmWLsbiUFuedtvSpp9QVA3 MexLqnzV09C4mWtxFbEyl5uHF16LrJdkCFubQeAk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726884AbfJ3T0o (ORCPT ); Wed, 30 Oct 2019 15:26:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:53904 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726769AbfJ3T0n (ORCPT ); Wed, 30 Oct 2019 15:26:43 -0400 Received: from localhost (unknown [84.241.198.167]) (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 5714820717; Wed, 30 Oct 2019 19:26:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572463603; bh=oZdsRq9DtlyqOY59UsuqYnw0hffYd6itQ5//OM9N0yo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EQphk4FxmCMxFxHG/5TYKSPi7YAgBs5IqWJDk/FAOpM+ZRPDtLpBZImpp4DiuE+Wb tzFvBrKBH0SaoI+5McjbOfZ6aDH8VO7HN+u3LOdtTMoGaywUTGTHn+o64hcAY6+Gdi ++vTdUeKWYBxIh31wAgLOz3E1h5el+0NtcEWvm1A= Date: Wed, 30 Oct 2019 20:26:40 +0100 From: Greg Kroah-Hartman To: Christoph Hellwig Cc: Kees Cook , 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: <20191030192640.GC709410@kroah.com> References: <20191029213423.28949-1-keescook@chromium.org> <20191029213423.28949-2-keescook@chromium.org> <20191030091849.GA637042@kroah.com> <20191030180921.GB19366@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191030180921.GB19366@lst.de> 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 Wed, Oct 30, 2019 at 07:09:21PM +0100, Christoph Hellwig wrote: > On Wed, Oct 30, 2019 at 10:18:49AM +0100, Greg Kroah-Hartman wrote: > > 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. > > I've fixed the message to "rejecting DMA map of vmalloc memory" and > applied the patch. Looks good! You can apply patch 2/2 as well if you want to take that through your tree too. thanks, greg k-h