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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 14713C433DF for ; Tue, 4 Aug 2020 09:58:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 12043206F6 for ; Tue, 4 Aug 2020 09:58:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729941AbgHDJ6T (ORCPT ); Tue, 4 Aug 2020 05:58:19 -0400 Received: from mga05.intel.com ([192.55.52.43]:26800 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726844AbgHDJ6T (ORCPT ); Tue, 4 Aug 2020 05:58:19 -0400 IronPort-SDR: A3dFxUuWuP/v7auN7hhQZvDFI2f2i1st2fHIEsYE6ErHYRHp8qNBmqKZYjbT0NDYSydH9H2SAH 78aE0JR4Oj+Q== X-IronPort-AV: E=McAfee;i="6000,8403,9702"; a="237143357" X-IronPort-AV: E=Sophos;i="5.75,433,1589266800"; d="scan'208";a="237143357" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Aug 2020 02:58:19 -0700 IronPort-SDR: rtJiswVjC6c+8iTGPxKrxJzxSqE725c84BDSnSra8GY500qn6+YrMQAGQa/lhh5Cfei2G9jtHQ hmWUthEDclVA== X-IronPort-AV: E=Sophos;i="5.75,433,1589266800"; d="scan'208";a="396527560" Received: from paasikivi.fi.intel.com ([10.237.72.42]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Aug 2020 02:58:17 -0700 Received: by paasikivi.fi.intel.com (Postfix, from userid 1000) id D843F20606; Tue, 4 Aug 2020 12:58:15 +0300 (EEST) Date: Tue, 4 Aug 2020 12:58:15 +0300 From: Sakari Ailus To: Bingbu Cao Cc: srinivas.kandagatla@linaro.org, linux-kernel@vger.kernel.org, bingbu.cao@linux.intel.com Subject: Re: [PATCH] nvmem: core: add sanity check in nvmem_device_read() Message-ID: <20200804095815.GF13316@paasikivi.fi.intel.com> References: <1596532436-19073-1-git-send-email-bingbu.cao@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1596532436-19073-1-git-send-email-bingbu.cao@intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Bingbu, Thank you for the patch. On Tue, Aug 04, 2020 at 05:13:56PM +0800, Bingbu Cao wrote: > nvmem_device_read() could be called directly once nvmem device > registered, the sanity check should be done before call > nvmem_reg_read() as cell and sysfs read did now. > > Signed-off-by: Bingbu Cao > --- > drivers/nvmem/core.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c > index 927eb5f6003f..c9a77993f008 100644 > --- a/drivers/nvmem/core.c > +++ b/drivers/nvmem/core.c > @@ -1491,6 +1491,13 @@ int nvmem_device_read(struct nvmem_device *nvmem, > if (!nvmem) > return -EINVAL; > > + if (offset >= nvmem->size || bytes < nvmem->word_size) > + return 0; > + > + if (bytes + offset > nvmem->size) > + bytes = nvmem->size - offset; The check is relevant for nvmem_device_write(), too. There are also other ways to access nvmem devices such as nvmem_cell_read and others alike. Should they be considered as well? > + > + bytes = round_down(bytes, nvmem->word_size); > rc = nvmem_reg_read(nvmem, offset, buf, bytes); > > if (rc) -- Kind regards, Sakari Ailus