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=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 E427AC3A59D for ; Fri, 16 Aug 2019 20:49:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B1D262077C for ; Fri, 16 Aug 2019 20:49:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727654AbfHPUtN (ORCPT ); Fri, 16 Aug 2019 16:49:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60832 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727568AbfHPUtN (ORCPT ); Fri, 16 Aug 2019 16:49:13 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 3D3F4301D678; Fri, 16 Aug 2019 20:49:12 +0000 (UTC) Received: from segfault.boston.devel.redhat.com (segfault.boston.devel.redhat.com [10.19.60.26]) by smtp.corp.redhat.com (Postfix) with ESMTPS id BF22519C6A; Fri, 16 Aug 2019 20:49:11 +0000 (UTC) From: Jeff Moyer To: Dan Williams Cc: linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] libnvdimm/security: Tighten scope of nvdimm->busy vs security operations References: <156583201347.2815870.4687949334637966672.stgit@dwillia2-desk3.amr.corp.intel.com> <156583202386.2815870.16611751329252858110.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: Fri, 16 Aug 2019 16:49:10 -0400 In-Reply-To: <156583202386.2815870.16611751329252858110.stgit@dwillia2-desk3.amr.corp.intel.com> (Dan Williams's message of "Wed, 14 Aug 2019 18:20:23 -0700") 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 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.47]); Fri, 16 Aug 2019 20:49:12 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dan Williams writes: > The blanket blocking of all security operations while the DIMM is in > active use in a region is too restrictive. The only security operations > that need to be aware of the ->busy state are those that mutate the > state of data, i.e. erase and overwrite. > > Refactor the ->busy checks to be applied at the entry common entry point > in __security_store() rather than each of the helper routines. I'm not sure this buys you much. Did you test this on actual hardware to make sure your assumptions are correct? I guess the worst case is we get an "invalid security state" error back from the firmware.... Still, what's the motivation for this? -Jeff > > Cc: Dave Jiang > Signed-off-by: Dan Williams > --- > drivers/nvdimm/dimm_devs.c | 33 ++++++++++++++++----------------- > drivers/nvdimm/security.c | 10 ---------- > 2 files changed, 16 insertions(+), 27 deletions(-) > > diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c > index 53330625fe07..d837cb9be83d 100644 > --- a/drivers/nvdimm/dimm_devs.c > +++ b/drivers/nvdimm/dimm_devs.c > @@ -424,9 +424,6 @@ static ssize_t __security_store(struct device *dev, const char *buf, size_t len) > unsigned int key, newkey; > int i; > > - if (atomic_read(&nvdimm->busy)) > - return -EBUSY; > - > rc = sscanf(buf, "%"__stringify(SEC_CMD_SIZE)"s" > " %"__stringify(KEY_ID_SIZE)"s" > " %"__stringify(KEY_ID_SIZE)"s", > @@ -451,23 +448,25 @@ static ssize_t __security_store(struct device *dev, const char *buf, size_t len) > } else if (i == OP_DISABLE) { > dev_dbg(dev, "disable %u\n", key); > rc = nvdimm_security_disable(nvdimm, key); > - } else if (i == OP_UPDATE) { > - dev_dbg(dev, "update %u %u\n", key, newkey); > - rc = nvdimm_security_update(nvdimm, key, newkey, NVDIMM_USER); > - } else if (i == OP_ERASE) { > - dev_dbg(dev, "erase %u\n", key); > - rc = nvdimm_security_erase(nvdimm, key, NVDIMM_USER); > + } else if (i == OP_UPDATE || i == OP_MASTER_UPDATE) { > + dev_dbg(dev, "%s %u %u\n", ops[i].name, key, newkey); > + rc = nvdimm_security_update(nvdimm, key, newkey, i == OP_UPDATE > + ? NVDIMM_USER : NVDIMM_MASTER); > + } else if (i == OP_ERASE || i == OP_MASTER_ERASE) { > + dev_dbg(dev, "%s %u\n", ops[i].name, key); > + if (atomic_read(&nvdimm->busy)) { > + dev_dbg(dev, "Unable to secure erase while DIMM active.\n"); > + return -EBUSY; > + } > + rc = nvdimm_security_erase(nvdimm, key, i == OP_ERASE > + ? NVDIMM_USER : NVDIMM_MASTER); > } else if (i == OP_OVERWRITE) { > dev_dbg(dev, "overwrite %u\n", key); > + if (atomic_read(&nvdimm->busy)) { > + dev_dbg(dev, "Unable to overwrite while DIMM active.\n"); > + return -EBUSY; > + } > rc = nvdimm_security_overwrite(nvdimm, key); > - } else if (i == OP_MASTER_UPDATE) { > - dev_dbg(dev, "master_update %u %u\n", key, newkey); > - rc = nvdimm_security_update(nvdimm, key, newkey, > - NVDIMM_MASTER); > - } else if (i == OP_MASTER_ERASE) { > - dev_dbg(dev, "master_erase %u\n", key); > - rc = nvdimm_security_erase(nvdimm, key, > - NVDIMM_MASTER); > } else > return -EINVAL; > > diff --git a/drivers/nvdimm/security.c b/drivers/nvdimm/security.c > index 5862d0eee9db..2166e627383a 100644 > --- a/drivers/nvdimm/security.c > +++ b/drivers/nvdimm/security.c > @@ -334,11 +334,6 @@ int nvdimm_security_erase(struct nvdimm *nvdimm, unsigned int keyid, > || !nvdimm->sec.flags) > return -EOPNOTSUPP; > > - if (atomic_read(&nvdimm->busy)) { > - dev_dbg(dev, "Unable to secure erase while DIMM active.\n"); > - return -EBUSY; > - } > - > rc = check_security_state(nvdimm); > if (rc) > return rc; > @@ -380,11 +375,6 @@ int nvdimm_security_overwrite(struct nvdimm *nvdimm, unsigned int keyid) > || !nvdimm->sec.flags) > return -EOPNOTSUPP; > > - if (atomic_read(&nvdimm->busy)) { > - dev_dbg(dev, "Unable to overwrite while DIMM active.\n"); > - return -EBUSY; > - } > - > if (dev->driver == NULL) { > dev_dbg(dev, "Unable to overwrite while DIMM active.\n"); > return -EINVAL; > > _______________________________________________ > Linux-nvdimm mailing list > Linux-nvdimm@lists.01.org > https://lists.01.org/mailman/listinfo/linux-nvdimm