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[209.132.180.67]) by mx.google.com with ESMTP id p25-v6si3530348pfn.131.2018.06.27.04.29.48; Wed, 27 Jun 2018 04:30:02 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=onS2Mhoh; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753396AbeF0L3I (ORCPT + 99 others); Wed, 27 Jun 2018 07:29:08 -0400 Received: from mail-wm0-f43.google.com ([74.125.82.43]:33803 "EHLO mail-wm0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752063AbeF0L3H (ORCPT ); Wed, 27 Jun 2018 07:29:07 -0400 Received: by mail-wm0-f43.google.com with SMTP id l15-v6so17777158wmc.1 for ; Wed, 27 Jun 2018 04:29:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=jHuYdizrSi1ltbbTMOTvJ4+F/zm2a2C+RpEM2sMXjC0=; b=onS2MhohNqrN2JlJL0sg/lmSjJevt/PMjSywDv8DX0Qae2SyirsOKUxRYHZmusifCF tOvMVzEd9puUuNPM2mVGWHgjdXXCVjCq6tGBFPNSVT8+irsNvK3KAGDazEE7dPgx4orX 1U8NsFLSUb08U3y+6eLihLSLYANWWk3xXvGVbqa9JiIMWqjElEGajDmBCsDYg+MmsJ82 IUBZa0YgvkdmDgYRV1h3LN9kUb8rA7MvxCmPcyXYZ1ZueOMs/ep4W5FUnKU1+vbC9UVa oiA4VktHltuniIv3bKpzbX5DlvKbmSk0Q5EyiONAj2b+8y2Z7Hzgeer4CywY3+U6lQDw xR7A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=jHuYdizrSi1ltbbTMOTvJ4+F/zm2a2C+RpEM2sMXjC0=; b=QgN7EgcyznFfgOX1KyNiBniy/H8SHqideMcWrplvJo9NGD/u6SN9tEuO2VgVFLErvM OF/TYQ1SnqH9R2F8Ld6mouPVpbPhj1+OdGreHZjuFazo6ofbOqiQi8iC8Vxt3qiLFXHb cJwYDgGrrZ4GUlA9Q0C+kYeuv4lwgBeadTNx7Ac4ozoxtAd+DJWZU2AqgsYKETOlg6fT QhtzASawUq3zGGb19V/uPESFxCtg0YF9hnUdkQA4/8aA/ps5Fcczza6Xi7JjddTX1hpn L8uQPDPuTSI2+Bwcs2eMVAY/cENZthL+c6DBLueTkvLeeE5S78Sw+nNMk66IBre/jPEd UxgA== X-Gm-Message-State: APt69E1q+iFqP0LEZ9lQqWqLjM7yak2Lep3O5cOhERZwWTPCDymkmDf2 GmlW5d+GSDeqJ/qJ+jApV6xuk3dbgYsnoRyyjT8= X-Received: by 2002:a1c:2fc7:: with SMTP id v190-v6mr4545734wmv.151.1530098945934; Wed, 27 Jun 2018 04:29:05 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a5d:480b:0:0:0:0:0 with HTTP; Wed, 27 Jun 2018 04:29:05 -0700 (PDT) In-Reply-To: <71d13d76-4591-9206-ebbb-5e9599f10c7c@gmail.com> References: <71d13d76-4591-9206-ebbb-5e9599f10c7c@gmail.com> From: Richard Weinberger Date: Wed, 27 Jun 2018 13:29:05 +0200 Message-ID: Subject: Re: Memory zeroed when made available to user process To: Jefferson Carpenter Cc: Linux Kernel Mailing List 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 Wed, Jun 27, 2018 at 11:34 AM, Jefferson Carpenter wrote: > Is there a way for a user process to mark memory as 'sensitive' or > 'non-sensitive' when it is allocated? That could allow it not to have to be > zeroed before being allocated to another process. Isn't this what we have Meltdown and Spectre for? ;-) No, memory from the kernel is always zeroed. libc offers malloc() and calloc() for this purpose. -- Thanks, //richard