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=-10.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 468AEC4727F for ; Wed, 30 Sep 2020 11:02:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 17D912076B for ; Wed, 30 Sep 2020 11:02:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728500AbgI3LCl (ORCPT ); Wed, 30 Sep 2020 07:02:41 -0400 Received: from mga11.intel.com ([192.55.52.93]:13342 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725779AbgI3LCl (ORCPT ); Wed, 30 Sep 2020 07:02:41 -0400 IronPort-SDR: lfDDrDvhcbR1xdG9MaQe9cLe8UBZj/9mTy2uGmydTLB4Uxa4/5ElWaK8y7hmatgN42WrtN/dc4 ZtT538pwB52g== X-IronPort-AV: E=McAfee;i="6000,8403,9759"; a="159759449" X-IronPort-AV: E=Sophos;i="5.77,322,1596524400"; d="scan'208";a="159759449" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Sep 2020 04:02:39 -0700 IronPort-SDR: BCBhpW2bM7uRhFpHn8NfauXkbtTodbaBTF74YvZqsiFBo3+pWYI9cpHAypBJOR2Trtyaw/c1SV z1ct+EYmD8wQ== X-IronPort-AV: E=Sophos;i="5.77,322,1596524400"; d="scan'208";a="496985713" Received: from lbentzio-mobl.ger.corp.intel.com (HELO localhost) ([10.252.32.88]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Sep 2020 04:02:37 -0700 Date: Wed, 30 Sep 2020 14:02:34 +0300 From: Jarkko Sakkinen To: James Bottomley Cc: linux-integrity@vger.kernel.org, Mimi Zohar , David Woodhouse , keyrings@vger.kernel.org, David Howells Subject: Re: [PATCH v13 3/5] security: keys: trusted: fix TPM2 authorizations Message-ID: <20200930110227.GA5145@linux.intel.com> References: <20200922022809.7105-1-James.Bottomley@HansenPartnership.com> <20200922022809.7105-4-James.Bottomley@HansenPartnership.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200922022809.7105-4-James.Bottomley@HansenPartnership.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Mon, Sep 21, 2020 at 07:28:07PM -0700, James Bottomley wrote: > In TPM 1.2 an authorization was a 20 byte number. The spec actually > recommended you to hash variable length passwords and use the sha1 > hash as the authorization. Because the spec doesn't require this > hashing, the current authorization for trusted keys is a 40 digit hex > number. For TPM 2.0 the spec allows the passing in of variable length > passwords and passphrases directly, so we should allow that in trusted > keys for ease of use. Update the 'blobauth' parameter to take this > into account, so we can now use plain text passwords for the keys. > > so before > > keyctl add trusted kmk "new 32 blobauth=f572d396fae9206628714fb2ce00f72e94f2258fkeyhandle=81000001" @u > > after we will accept both the old hex sha1 form as well as a new > directly supplied password: > > keyctl add trusted kmk "new 32 blobauth=hello keyhandle=81000001" @u > > Since a sha1 hex code must be exactly 40 bytes long and a direct > password must be 20 or less, we use the length as the discriminator > for which form is input. > > Note this is both and enhancement and a potential bug fix. The TPM > 2.0 spec requires us to strip leading zeros, meaning empyty > authorization is a zero length HMAC whereas we're currently passing in > 20 bytes of zeros. A lot of TPMs simply accept this as OK, but the > Microsoft TPM emulator rejects it with TPM_RC_BAD_AUTH, so this patch > makes the Microsoft TPM emulator work with trusted keys. > > Fixes: 0fe5480303a1 ("keys, trusted: seal/unseal with TPM 2.0 chips") > Signed-off-by: James Bottomley > Reviewed-by: Jarkko Sakkinen > > --- > > v6: change comment, eliminate else clauses and add fixes tag > v7: fixes before signoff > v12: fix mismerge from v6 to make processing continue after blobauth > > Merge with auth fix > --- > include/keys/trusted-type.h | 1 + > security/keys/trusted-keys/trusted_tpm1.c | 32 ++++++++++++++++++----- > security/keys/trusted-keys/trusted_tpm2.c | 10 ++++--- > 3 files changed, 33 insertions(+), 10 deletions(-) > > diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h > index a94c03a61d8f..b2ed3481c6a0 100644 > --- a/include/keys/trusted-type.h > +++ b/include/keys/trusted-type.h > @@ -30,6 +30,7 @@ struct trusted_key_options { > uint16_t keytype; > uint32_t keyhandle; > unsigned char keyauth[TPM_DIGEST_SIZE]; > + uint32_t blobauth_len; > unsigned char blobauth[TPM_DIGEST_SIZE]; > uint32_t pcrinfo_len; > unsigned char pcrinfo[MAX_PCRINFO_SIZE]; > diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c > index b9fe02e5f84f..eaa2e7ca136e 100644 > --- a/security/keys/trusted-keys/trusted_tpm1.c > +++ b/security/keys/trusted-keys/trusted_tpm1.c > @@ -781,13 +781,33 @@ static int getoptions(char *c, struct trusted_key_payload *pay, > return -EINVAL; > break; > case Opt_blobauth: > - if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE) > - return -EINVAL; > - res = hex2bin(opt->blobauth, args[0].from, > - SHA1_DIGEST_SIZE); > - if (res < 0) > - return -EINVAL; > + /* > + * TPM 1.2 authorizations are sha1 hashes passed in as > + * hex strings. TPM 2.0 authorizations are simple > + * passwords (although it can take a hash as well) > + */ > + opt->blobauth_len = strlen(args[0].from); > + > + if (opt->blobauth_len == 2 * TPM_DIGEST_SIZE) { > + res = hex2bin(opt->blobauth, args[0].from, > + TPM_DIGEST_SIZE); > + if (res < 0) > + return -EINVAL; > + > + opt->blobauth_len = TPM_DIGEST_SIZE; > + break; > + } > + > + if (tpm2 && opt->blobauth_len <= sizeof(opt->blobauth)) { > + memcpy(opt->blobauth, args[0].from, > + opt->blobauth_len); > + break; > + } > + > + return -EINVAL; > + > break; > + > case Opt_migratable: > if (*args[0].from == '0') > pay->migratable = 0; > diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c > index 08ec7f48f01d..b4a5058107c2 100644 > --- a/security/keys/trusted-keys/trusted_tpm2.c > +++ b/security/keys/trusted-keys/trusted_tpm2.c > @@ -91,10 +91,12 @@ int tpm2_seal_trusted(struct tpm_chip *chip, > TPM_DIGEST_SIZE); > > /* sensitive */ > - tpm_buf_append_u16(&buf, 4 + TPM_DIGEST_SIZE + payload->key_len + 1); > + tpm_buf_append_u16(&buf, 4 + options->blobauth_len + payload->key_len + 1); > + > + tpm_buf_append_u16(&buf, options->blobauth_len); > + if (options->blobauth_len) > + tpm_buf_append(&buf, options->blobauth, options->blobauth_len); > > - tpm_buf_append_u16(&buf, TPM_DIGEST_SIZE); > - tpm_buf_append(&buf, options->blobauth, TPM_DIGEST_SIZE); > tpm_buf_append_u16(&buf, payload->key_len + 1); > tpm_buf_append(&buf, payload->key, payload->key_len); > tpm_buf_append_u8(&buf, payload->migratable); > @@ -258,7 +260,7 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip, > NULL /* nonce */, 0, > TPM2_SA_CONTINUE_SESSION, > options->blobauth /* hmac */, > - TPM_DIGEST_SIZE); > + options->blobauth_len); > > rc = tpm_send(chip, buf.data, tpm_buf_length(&buf)); > if (rc > 0) > -- > 2.26.2 > Tested-by: Jarkko Sakkinen Transcript: ➜ tpm2-scripts (master) ✗ sudo ./tpm2-root-key 0x80000000 ➜ tpm2-scripts (master) ✗ sudo keyctl add trusted kmk "new 32 blobauth=hello keyhandle=80000000" @u 751240563 /Jarkko