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=-1.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 5DAB2C2D0EC for ; Tue, 7 Apr 2020 20:09:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 261C82063A for ; Tue, 7 Apr 2020 20:09:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586290173; bh=Z629Nfl1DdT+QE58IEZ1e1tt1UreJbGRlu7sbxcWNd8=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=HzfDBc+Nzo1u849mi6PoERfrp/AEZyCuw5+nWTHt6U/z8RbangopG/Vqp1+ZlRFJq 8QL5XkAUCRCajoD0+ISYDw3RIO0j1/26oPH1Mrx/7s17FSOO9GJ/816SQU1h6vsCE/ zJktmT6S9kEGv6dLnioQNwW9h+Scx9kEbqCwlNDQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727469AbgDGUJc (ORCPT ); Tue, 7 Apr 2020 16:09:32 -0400 Received: from mail-lj1-f194.google.com ([209.85.208.194]:41829 "EHLO mail-lj1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726840AbgDGUJb (ORCPT ); Tue, 7 Apr 2020 16:09:31 -0400 Received: by mail-lj1-f194.google.com with SMTP id n17so5158808lji.8 for ; Tue, 07 Apr 2020 13:09:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=3sghJldqMMjWeerVBLUfhc/cQuHU1aQm4qS6KijAW8Q=; b=LIs7mHA3OXPjMsaXtYIk07UvtJnPGY4OLuhw5yUdciWXo/7JrrEmPqgnrwGk7LYTDy rq/7n66O3MT27zCaMgmAZUsQHre2pHLQbaKY/YARTqgYJVheydI5BKhcTlTAQdZtVZZq 45bOqqTdfPd9zcZUW/Ki0gAVMMNSm+WBI9Bqk= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=3sghJldqMMjWeerVBLUfhc/cQuHU1aQm4qS6KijAW8Q=; b=mbi3pkYkrRrssiHeC2azZZSfuZVLZQDO6AQFEOlfw+BFLTqjyH2UqhRsqxJb5iUlY0 CcefXYk7C8ypPQdCRw6KOS2hTfJTA35SNDcuBfTkeYpcvHB1it5alR/99hhi/ZN8MIHL KpxI0Azdqk9aIvsEeToffxaQBF52JjaL0cZo+bY6h8MkI1mLov8yjWThiokg8JbSm0G/ g7EW4PsfGZHTOVycxm8XBWc4xTo5Q5hKamcV37Dxa0i4GRKtl3UikvZaF+foZEpHJjaK fCXJVCO0gjfV26IT5TQCKIA9QdAt7tHTdT+QxjgtJyyM3bZgwRa+fP3KMoc3VcEiuia8 fgoQ== X-Gm-Message-State: AGi0PuZzwNI9YTkAVP4IZ4tSj2qIpah6ni6ECW/BYglkuNiPUIvAYmlj 5I32O6OjQJXbNPk9e88dLroeWSDqr3c= X-Google-Smtp-Source: APiQypLYg6kLrEV1mmwd0kUorwiyt6sMZRNKEmXfsuLqjMiJ5OsQCpFhOY0ayCA6svg0kDhB6dWZTA== X-Received: by 2002:a2e:87cc:: with SMTP id v12mr2777717ljj.127.1586290168746; Tue, 07 Apr 2020 13:09:28 -0700 (PDT) Received: from mail-lj1-f172.google.com (mail-lj1-f172.google.com. [209.85.208.172]) by smtp.gmail.com with ESMTPSA id u7sm2140400lfi.0.2020.04.07.13.09.27 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 07 Apr 2020 13:09:27 -0700 (PDT) Received: by mail-lj1-f172.google.com with SMTP id 142so627409ljj.7 for ; Tue, 07 Apr 2020 13:09:27 -0700 (PDT) X-Received: by 2002:a2e:8911:: with SMTP id d17mr2856344lji.16.1586290167180; Tue, 07 Apr 2020 13:09:27 -0700 (PDT) MIME-Version: 1.0 References: <20200407200318.11711-1-longman@redhat.com> In-Reply-To: <20200407200318.11711-1-longman@redhat.com> From: Linus Torvalds Date: Tue, 7 Apr 2020 13:09:11 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v3] mm: Add kvfree_sensitive() for freeing sensitive data objects To: Waiman Long Cc: Andrew Morton , David Howells , Jarkko Sakkinen , James Morris , "Serge E. Hallyn" , Linux-MM , keyrings@vger.kernel.org, Linux Kernel Mailing List , Joe Perches , Matthew Wilcox , David Rientjes Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 7, 2020 at 1:03 PM 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. Ack. Since this isn't exactly high-priority, I'm assuming it will go through the usual channels (ie Andrew). Linus