From patchwork Wed Jun 5 21:58:58 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 10977991 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id F29701398 for ; Wed, 5 Jun 2019 22:13:17 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E28D1200DF for ; Wed, 5 Jun 2019 22:13:17 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D6A352890A; Wed, 5 Jun 2019 22:13:17 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 73D15200DF for ; Wed, 5 Jun 2019 22:13:17 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 66453212909C7; Wed, 5 Jun 2019 15:13:17 -0700 (PDT) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=192.55.52.151; helo=mga17.intel.com; envelope-from=dan.j.williams@intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id B9DE2212909C4 for ; Wed, 5 Jun 2019 15:13:15 -0700 (PDT) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Jun 2019 15:13:15 -0700 X-ExtLoop1: 1 Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by fmsmga005.fm.intel.com with ESMTP; 05 Jun 2019 15:13:15 -0700 Subject: [PATCH v9 11/12] libnvdimm/pfn: Fix fsdax-mode namespace info-block zero-fields From: Dan Williams To: akpm@linux-foundation.org Date: Wed, 05 Jun 2019 14:58:58 -0700 Message-ID: <155977193862.2443951.10284714500308539570.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <155977186863.2443951.9036044808311959913.stgit@dwillia2-desk3.amr.corp.intel.com> References: <155977186863.2443951.9036044808311959913.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-2-gc94f MIME-Version: 1.0 X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mhocko@suse.com, linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux-mm@kvack.org, osalvador@suse.de Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP At namespace creation time there is the potential for the "expected to be zero" fields of a 'pfn' info-block to be filled with indeterminate data. While the kernel buffer is zeroed on allocation it is immediately overwritten by nd_pfn_validate() filling it with the current contents of the on-media info-block location. For fields like, 'flags' and the 'padding' it potentially means that future implementations can not rely on those fields being zero. In preparation to stop using the 'start_pad' and 'end_trunc' fields for section alignment, arrange for fields that are not explicitly initialized to be guaranteed zero. Bump the minor version to indicate it is safe to assume the 'padding' and 'flags' are zero. Otherwise, this corruption is expected to benign since all other critical fields are explicitly initialized. Fixes: 32ab0a3f5170 ("libnvdimm, pmem: 'struct page' for pmem") Cc: Signed-off-by: Dan Williams --- drivers/nvdimm/dax_devs.c | 2 +- drivers/nvdimm/pfn.h | 1 + drivers/nvdimm/pfn_devs.c | 18 +++++++++++++++--- 3 files changed, 17 insertions(+), 4 deletions(-) diff --git a/drivers/nvdimm/dax_devs.c b/drivers/nvdimm/dax_devs.c index 0453f49dc708..326f02ffca81 100644 --- a/drivers/nvdimm/dax_devs.c +++ b/drivers/nvdimm/dax_devs.c @@ -126,7 +126,7 @@ int nd_dax_probe(struct device *dev, struct nd_namespace_common *ndns) nvdimm_bus_unlock(&ndns->dev); if (!dax_dev) return -ENOMEM; - pfn_sb = devm_kzalloc(dev, sizeof(*pfn_sb), GFP_KERNEL); + pfn_sb = devm_kmalloc(dev, sizeof(*pfn_sb), GFP_KERNEL); nd_pfn->pfn_sb = pfn_sb; rc = nd_pfn_validate(nd_pfn, DAX_SIG); dev_dbg(dev, "dax: %s\n", rc == 0 ? dev_name(dax_dev) : ""); diff --git a/drivers/nvdimm/pfn.h b/drivers/nvdimm/pfn.h index dde9853453d3..e901e3a3b04c 100644 --- a/drivers/nvdimm/pfn.h +++ b/drivers/nvdimm/pfn.h @@ -36,6 +36,7 @@ struct nd_pfn_sb { __le32 end_trunc; /* minor-version-2 record the base alignment of the mapping */ __le32 align; + /* minor-version-3 guarantee the padding and flags are zero */ u8 padding[4000]; __le64 checksum; }; diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c index 01f40672507f..a2406253eb70 100644 --- a/drivers/nvdimm/pfn_devs.c +++ b/drivers/nvdimm/pfn_devs.c @@ -420,6 +420,15 @@ static int nd_pfn_clear_memmap_errors(struct nd_pfn *nd_pfn) return 0; } +/** + * nd_pfn_validate - read and validate info-block + * @nd_pfn: fsdax namespace runtime state / properties + * @sig: 'devdax' or 'fsdax' signature + * + * Upon return the info-block buffer contents (->pfn_sb) are + * indeterminate when validation fails, and a coherent info-block + * otherwise. + */ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig) { u64 checksum, offset; @@ -565,7 +574,7 @@ int nd_pfn_probe(struct device *dev, struct nd_namespace_common *ndns) nvdimm_bus_unlock(&ndns->dev); if (!pfn_dev) return -ENOMEM; - pfn_sb = devm_kzalloc(dev, sizeof(*pfn_sb), GFP_KERNEL); + pfn_sb = devm_kmalloc(dev, sizeof(*pfn_sb), GFP_KERNEL); nd_pfn = to_nd_pfn(pfn_dev); nd_pfn->pfn_sb = pfn_sb; rc = nd_pfn_validate(nd_pfn, PFN_SIG); @@ -702,7 +711,7 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn) u64 checksum; int rc; - pfn_sb = devm_kzalloc(&nd_pfn->dev, sizeof(*pfn_sb), GFP_KERNEL); + pfn_sb = devm_kmalloc(&nd_pfn->dev, sizeof(*pfn_sb), GFP_KERNEL); if (!pfn_sb) return -ENOMEM; @@ -711,11 +720,14 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn) sig = DAX_SIG; else sig = PFN_SIG; + rc = nd_pfn_validate(nd_pfn, sig); if (rc != -ENODEV) return rc; /* no info block, do init */; + memset(pfn_sb, 0, sizeof(*pfn_sb)); + nd_region = to_nd_region(nd_pfn->dev.parent); if (nd_region->ro) { dev_info(&nd_pfn->dev, @@ -768,7 +780,7 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn) memcpy(pfn_sb->uuid, nd_pfn->uuid, 16); memcpy(pfn_sb->parent_uuid, nd_dev_to_uuid(&ndns->dev), 16); pfn_sb->version_major = cpu_to_le16(1); - pfn_sb->version_minor = cpu_to_le16(2); + pfn_sb->version_minor = cpu_to_le16(3); pfn_sb->start_pad = cpu_to_le32(start_pad); pfn_sb->end_trunc = cpu_to_le32(end_trunc); pfn_sb->align = cpu_to_le32(nd_pfn->align);