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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 DBE15C2BA17 for ; Mon, 6 Apr 2020 15:47:20 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 91692248CD for ; Mon, 6 Apr 2020 15:47:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 91692248CD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=perches.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1CC618E003B; Mon, 6 Apr 2020 11:47:20 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 156008E000D; Mon, 6 Apr 2020 11:47:20 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0445D8E003B; Mon, 6 Apr 2020 11:47:19 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0206.hostedemail.com [216.40.44.206]) by kanga.kvack.org (Postfix) with ESMTP id DE2CA8E000D for ; Mon, 6 Apr 2020 11:47:19 -0400 (EDT) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id AA150A8F5 for ; Mon, 6 Apr 2020 15:47:19 +0000 (UTC) X-FDA: 76677859398.28.army78_5b9c8f737d33 X-HE-Tag: army78_5b9c8f737d33 X-Filterd-Recvd-Size: 2870 Received: from smtprelay.hostedemail.com (smtprelay0224.hostedemail.com [216.40.44.224]) by imf06.hostedemail.com (Postfix) with ESMTP for ; Mon, 6 Apr 2020 15:47:19 +0000 (UTC) Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay03.hostedemail.com (Postfix) with ESMTP id E5AA38378BBE; Mon, 6 Apr 2020 15:47:18 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: paper59_5695de72003b X-Filterd-Recvd-Size: 1721 Received: from XPS-9350.home (unknown [47.151.136.130]) (Authenticated sender: joe@perches.com) by omf14.hostedemail.com (Postfix) with ESMTPA; Mon, 6 Apr 2020 15:47:17 +0000 (UTC) Message-ID: Subject: Re: [PATCH] mm: Add kvfree_sensitive() for freeing sensitive data objects From: Joe Perches To: Waiman Long , Andrew Morton , David Howells , Jarkko Sakkinen , James Morris , "Serge E. Hallyn" Cc: linux-mm@kvack.org, keyrings@vger.kernel.org, linux-kernel@vger.kernel.org, Linus Torvalds Date: Mon, 06 Apr 2020 08:45:18 -0700 In-Reply-To: <20200406023700.1367-1-longman@redhat.com> References: <20200406023700.1367-1-longman@redhat.com> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.34.1-2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sun, 2020-04-05 at 22:37 -0400, Waiman Long wrote: > For kvmalloc'ed data object that contains sensitive information like > cryptographic key, we need to make sure that the buffer is always > cleared before freeing it. Using memset() alone for buffer clearing may > not provide certainty as the compiler may compile it away. To be sure, > the special memzero_explicit() has to be used. > > This patch introduces a new kvfree_sensitive() for freeing those > sensitive data objects allocated by kvmalloc(). The relevnat places > where kvfree_sensitive() can be used are modified to use it. Why isn't this called kvzfree like the existing kzfree?