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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 86E74C43387 for ; Tue, 15 Jan 2019 20:39:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5E32720656 for ; Tue, 15 Jan 2019 20:39:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389935AbfAOUj1 (ORCPT ); Tue, 15 Jan 2019 15:39:27 -0500 Received: from mx1.redhat.com ([209.132.183.28]:61602 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389878AbfAOUjQ (ORCPT ); Tue, 15 Jan 2019 15:39:16 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8A6D383F3E; Tue, 15 Jan 2019 20:39:15 +0000 (UTC) Received: from segfault.boston.devel.redhat.com (unknown [10.18.25.74]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B0E3C5C234; Tue, 15 Jan 2019 20:39:14 +0000 (UTC) From: Jeff Moyer To: Dan Williams Cc: linux-nvdimm , stable , stuart hayes , Sujith Pandel , Vishal Verma , Linux Kernel Mailing List Subject: Re: [PATCH v2 0/2] acpi/nfit: Fix command-supported detection References: <154751742416.1617064.8252289468130584022.stgit@dwillia2-desk3.amr.corp.intel.com> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 Date: Tue, 15 Jan 2019 15:39:13 -0500 In-Reply-To: (Dan Williams's message of "Tue, 15 Jan 2019 08:48:18 -0800") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Tue, 15 Jan 2019 20:39:15 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dan Williams writes: > On Tue, Jan 15, 2019 at 6:16 AM Jeff Moyer wrote: >> >> Dan Williams writes: >> >> > Changes since v1 [1]: >> > * Include another patch make sure that function-number zero can be >> > safely used as an invalid function number (Jeff) >> > * Add a comment clarifying why zero is an invalid function number (Jeff) >> > * Pass nfit_mem to cmd_to_func() (Jeff) >> > * Collect a Tested-by from Sujith >> > [1]: https://lists.01.org/pipermail/linux-nvdimm/2019-January/019435.html >> >> For the series: >> >> Reviewed-by: Jeff Moyer >> >> Thanks, Dan! > > Thanks, although I just realized one more change. The ND_CMD_CALL case > should zero out command after the function translation, otherwise > userspace can call functions that the kernel is blocking in the > dsm_mask. > > Holler if this invalidates your "Reviewed-by". AAAAAAAHHHHHHHHHH!!!! :) > diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c > index 87e02f281e51..d7747aceb7ab 100644 > --- a/drivers/acpi/nfit/core.c > +++ b/drivers/acpi/nfit/core.c > @@ -463,6 +463,12 @@ int acpi_nfit_ctl(struct nvdimm_bus_descriptor > *nd_desc, struct nvdimm *nvdimm, > func = cmd_to_func(nfit_mem, cmd, buf); > if (func < 0) > return func; > + /* > + * In the ND_CMD_CALL case we're now dependent on 'func' > + * being validated by the dimm's dsm_mask > + */ > + if (cmd == ND_CMD_CALL) > + cmd = 0; > dimm_name = nvdimm_name(nvdimm); > cmd_name = nvdimm_cmd_name(cmd); > cmd_mask = nvdimm_cmd_mask(nvdimm); dsm_mask = nfit_mem->dsm_mask; desc = nd_cmd_dimm_desc(cmd); That sure doesn't look right. Now cmd_name and desc will be wrong. > @@ -477,8 +483,10 @@ int acpi_nfit_ctl(struct nvdimm_bus_descriptor > *nd_desc, struct nvdimm *nvdimm, > cmd_name = nvdimm_bus_cmd_name(cmd); > cmd_mask = nd_desc->cmd_mask; > dsm_mask = cmd_mask; > - if (cmd == ND_CMD_CALL) > + if (cmd == ND_CMD_CALL) { > dsm_mask = nd_desc->bus_dsm_mask; > + cmd = 0; > + } > desc = nd_cmd_bus_desc(cmd); And again here. We could reorder the zeroing, or you could modify the check for a valid comand/function. Something like this? /* * Check for a valid command. For ND_CMD_CALL, we also * have to make sure that the DSM function is supported. */ if (cmd == ND_CMD_CALL && !test_bit(func, &dsm_mask)) return -ENOTTY; else if (!test_bit(cmd, &cmd_mask)) return -ENOTTY; Which way do you think is cleaner? Cheers, Jeff