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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 20442C32754 for ; Fri, 2 Aug 2019 15:30:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EC21A2087C for ; Fri, 2 Aug 2019 15:30:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733162AbfHBPaq (ORCPT ); Fri, 2 Aug 2019 11:30:46 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:57690 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733136AbfHBPap (ORCPT ); Fri, 2 Aug 2019 11:30:45 -0400 Received: from 162-237-133-238.lightspeed.rcsntx.sbcglobal.net ([162.237.133.238] helo=elm) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1htZVr-0001Mo-Ax; Fri, 02 Aug 2019 15:30:35 +0000 Date: Fri, 2 Aug 2019 10:30:30 -0500 From: Tyler Hicks To: Roberto Sassu Cc: jarkko.sakkinen@linux.intel.com, jejb@linux.ibm.com, zohar@linux.ibm.com, jgg@ziepe.ca, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, keyrings@vger.kernel.org, linux-kernel@vger.kernel.org, crazyt2019+lml@gmail.com, nayna@linux.vnet.ibm.com, silviu.vlasceanu@huawei.com Subject: Re: [PATCH v2] KEYS: trusted: allow module init if TPM is inactive or deactivated Message-ID: <20190802153030.GB26616@elm> References: <20190802150733.1972-1-roberto.sassu@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190802150733.1972-1-roberto.sassu@huawei.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On 2019-08-02 17:07:33, Roberto Sassu wrote: > Commit c78719203fc6 ("KEYS: trusted: allow trusted.ko to initialize w/o a > TPM") allows the trusted module to be loaded even a TPM is not found to ^ if > avoid module dependency problems. > > However, trusted module initialization can still fail if the TPM is > inactive or deactivated. This patch ignores tpm_get_random() errors in > init_digests() and returns -EFAULT in pcrlock() if the TPM didn't return > random data. > > Signed-off-by: Roberto Sassu The code changes look correct to me. Reviewed-by: Tyler Hicks For whoever takes this patch through their tree, I think that adding the following Fixes tag would be useful (as well as cc'ing stable): Fixes: 240730437deb ("KEYS: trusted: explicitly use tpm_chip structure...") I think it is also worth leaving a short note, in the commit message, for backporters that commit 782779b60faa ("tpm: Actually fail on TPM errors during "get random"") should be included with any backports of this patch. Thanks! Tyler > --- > security/keys/trusted.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/security/keys/trusted.c b/security/keys/trusted.c > index 9a94672e7adc..34f04ffcf2e5 100644 > --- a/security/keys/trusted.c > +++ b/security/keys/trusted.c > @@ -389,6 +389,10 @@ static int pcrlock(const int pcrnum) > if (!capable(CAP_SYS_ADMIN)) > return -EPERM; > > + /* This happens if the TPM didn't return random data */ > + if (!digests) > + return -EFAULT; > + > return tpm_pcr_extend(chip, pcrnum, digests) ? -EINVAL : 0; > } > > @@ -1233,10 +1237,8 @@ static int __init init_digests(void) > int i; > > ret = tpm_get_random(chip, digest, TPM_MAX_DIGEST_SIZE); > - if (ret < 0) > - return ret; > - if (ret < TPM_MAX_DIGEST_SIZE) > - return -EFAULT; > + if (ret < 0 || ret < TPM_MAX_DIGEST_SIZE) > + return 0; > > digests = kcalloc(chip->nr_allocated_banks, sizeof(*digests), > GFP_KERNEL); > -- > 2.17.1 >