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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 982E7C43219 for ; Thu, 2 May 2019 06:10:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 70C0C2085A for ; Thu, 2 May 2019 06:10:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726694AbfEBGKU (ORCPT ); Thu, 2 May 2019 02:10:20 -0400 Received: from mga02.intel.com ([134.134.136.20]:47385 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726231AbfEBGKT (ORCPT ); Thu, 2 May 2019 02:10:19 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 01 May 2019 23:10:08 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,420,1549958400"; d="scan'208";a="145342058" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by fmsmga008.fm.intel.com with ESMTP; 01 May 2019 23:10:07 -0700 Subject: [PATCH v7 11/12] libnvdimm/pfn: Fix fsdax-mode namespace info-block zero-fields From: Dan Williams To: akpm@linux-foundation.org Cc: stable@vger.kernel.org, linux-nvdimm@lists.01.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, osalvador@suse.de, mhocko@suse.com Date: Wed, 01 May 2019 22:56:21 -0700 Message-ID: <155677658129.2336373.14466297657474148349.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <155677652226.2336373.8700273400832001094.stgit@dwillia2-desk3.amr.corp.intel.com> References: <155677652226.2336373.8700273400832001094.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-2-gc94f MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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);