From: PrasannaKumar Muralidharan Subject: Re: [tpmdd-devel] [PATCH] tpm: remove chip_num parameter from in-kernel API Date: Tue, 24 Oct 2017 21:37:33 +0530 Message-ID: References: <20171023123817.18559-1-jarkko.sakkinen@linux.intel.com> <20171023163139.GA17394@obsidianresearch.com> <20171024154440.3jeupmus43jcgbbz@linux.intel.com> <20171024155526.GA32250@obsidianresearch.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: Jarkko Sakkinen , Stefan Berger , linux-integrity@vger.kernel.org, David Howells , Herbert Xu , "open list:INTEGRITY MEASUREMENT ARCHITECTURE IMA" , Dmitry Kasatkin , open list , linux-security-module@vger.kernel.org, "moderated list:TPM DEVICE DRIVER" , "open list:KEYS-TRUSTED" , "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" , James Morris , Matt Mackall , "open list:INTEGRITY MEASUREMENT ARCHITECTURE IMA" To: Jason Gunthorpe Return-path: Received: from mail-io0-f195.google.com ([209.85.223.195]:43909 "EHLO mail-io0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751336AbdJXQHf (ORCPT ); Tue, 24 Oct 2017 12:07:35 -0400 In-Reply-To: <20171024155526.GA32250@obsidianresearch.com> Sender: linux-crypto-owner@vger.kernel.org List-ID: Hi Jason, On 24 October 2017 at 21:25, Jason Gunthorpe wrote: > On Tue, Oct 24, 2017 at 09:21:15PM +0530, PrasannaKumar Muralidharan wrote: > >> Please check the RFC [1]. It does use chip id. The rfc has issues and >> has to be fixed but still there could be users of the API. >> >> 1. https://www.spinics.net/lists/linux-crypto/msg28282.html > > That patch isn't safe at all. You need to store a kref to th chip in > the hwrng, not parse a string. The drivers/char/hw_random/tpm-rng.c module does not store the chip reference so I guess the usage is safe. The RFC is just a sample use case of the API. Regards, PrasannaKumar