From patchwork Mon Dec 30 17:38:02 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Bottomley X-Patchwork-Id: 11313591 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 79A81139A for ; Mon, 30 Dec 2019 17:44:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4DED82071E for ; Mon, 30 Dec 2019 17:44:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b="kgDKx6oQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727236AbfL3RoL (ORCPT ); Mon, 30 Dec 2019 12:44:11 -0500 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:39538 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726602AbfL3RoK (ORCPT ); Mon, 30 Dec 2019 12:44:10 -0500 Received: from localhost (localhost [127.0.0.1]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id 980508EE15F; Mon, 30 Dec 2019 09:44:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=hansenpartnership.com; s=20151216; t=1577727850; bh=caVNe0qmmW/yVqiTXrtklhxmMk2KQ4fhsW2nFHKjueg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kgDKx6oQEynoaReOHEMZiXrK0Sv7YCaPj11lGFso5HzS1QQO9zOnrcBCshmdEuzDU R/VIgkkuWnM9EnXv5zlZx6usRFSCaYVT4DQ3f1woVs1dN8SDQThYmNphi9nAzYkGLJ mYP0qcwWBTFn6+4d5nA+0GVfrMxeLXu+AqZN+Trc= Received: from bedivere.hansenpartnership.com ([127.0.0.1]) by localhost (bedivere.hansenpartnership.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id GEBIVRXBVmxr; Mon, 30 Dec 2019 09:44:10 -0800 (PST) Received: from jarvis.int.hansenpartnership.com (jarvis.ext.hansenpartnership.com [153.66.160.226]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id 33D258EE07B; Mon, 30 Dec 2019 09:44:10 -0800 (PST) From: James Bottomley To: linux-integrity@vger.kernel.org Cc: Mimi Zohar , Jarkko Sakkinen , David Woodhouse , keyrings@vger.kernel.org Subject: [PATCH v4 9/9] security: keys: trusted: add password based authorizations to policy keys Date: Mon, 30 Dec 2019 09:38:02 -0800 Message-Id: <20191230173802.8731-10-James.Bottomley@HansenPartnership.com> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20191230173802.8731-1-James.Bottomley@HansenPartnership.com> References: <20191230173802.8731-1-James.Bottomley@HansenPartnership.com> Sender: keyrings-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: keyrings@vger.kernel.org TPM 2.0 has a trick where you can turn off the usual HMAC password session requirement using TPM2_PolicyPassword, so everywhere we see a TPM2_PolicyAuthValue (which does require HMAC password), we replace with the TPM2_PolicyPassword command instead. This allows us to use passwords with TPM 2.0 trusted keys that also have a policy. Signed-off-by: James Bottomley --- include/linux/tpm.h | 1 + security/keys/trusted-keys/tpm2-policy.c | 16 ++++++++++++++- security/keys/trusted-keys/trusted_tpm2.c | 34 ++++++++++++++++++++++++++++++- 3 files changed, 49 insertions(+), 2 deletions(-) diff --git a/include/linux/tpm.h b/include/linux/tpm.h index e32e9728adce..5026a06977e1 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -233,6 +233,7 @@ enum tpm2_command_codes { TPM2_CC_PCR_EXTEND = 0x0182, TPM2_CC_EVENT_SEQUENCE_COMPLETE = 0x0185, TPM2_CC_HASH_SEQUENCE_START = 0x0186, + TPM2_CC_POLICY_PASSWORD = 0x018c, TPM2_CC_CREATE_LOADED = 0x0191, TPM2_CC_LAST = 0x0193, /* Spec 1.36 */ }; diff --git a/security/keys/trusted-keys/tpm2-policy.c b/security/keys/trusted-keys/tpm2-policy.c index 3c7a8e6c84c8..2c93197edf2b 100644 --- a/security/keys/trusted-keys/tpm2-policy.c +++ b/security/keys/trusted-keys/tpm2-policy.c @@ -193,7 +193,8 @@ int tpm2_generate_policy_digest(struct tpm2_policies *pols, policy = digest; len = *plen; } - crypto_shash_update(sdesc, policy, len); + if (len) + crypto_shash_update(sdesc, policy, len); /* now output the intermediate to the policydigest */ crypto_shash_final(sdesc, policydigest); @@ -316,6 +317,16 @@ int tpm2_get_policy_session(struct tpm_chip *chip, struct tpm2_policies *pols, u32 cmd = pols->code[i]; struct tpm_buf buf; + if (cmd == TPM2_CC_POLICY_AUTHVALUE) + /* + * both PolicyAuthValue and PolicyPassword + * hash to the same thing, but one triggers + * HMAC authentication and the other simple + * authentication. Since we have no HMAC + * code, we're choosing the simple + */ + cmd = TPM2_CC_POLICY_PASSWORD; + rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, cmd); if (rc) return rc; @@ -357,6 +368,9 @@ int tpm2_get_policy_session(struct tpm_chip *chip, struct tpm2_policies *pols, } default: failure = "unknown policy"; + if (pols->len[i]) + tpm_buf_append(&buf, pols->policies[i], + pols->len[i]); break; } rc = tpm_send(chip, buf.data, tpm_buf_length(&buf)); diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c index 1f039b39aa7f..169846fde5f7 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -244,6 +244,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip, u32 flags; int i; int rc; + static const int POLICY_SIZE = 2 * PAGE_SIZE; for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) { if (options->hash == tpm2_hash_map[i].crypto_id) { @@ -264,7 +265,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip, /* 4 array len, 2 hash alg */ const int len = 4 + 2 + options->pcrinfo_len; - pols = kmalloc(sizeof(*pols) + len, GFP_KERNEL); + pols = kmalloc(POLICY_SIZE, GFP_KERNEL); if (!pols) return -ENOMEM; @@ -285,6 +286,37 @@ int tpm2_seal_trusted(struct tpm_chip *chip, return -EINVAL; } + /* + * if we already have a policy, we have to add authorization + * to it. If we don't, we can simply follow the usual + * non-policy route. + */ + if (options->blobauth_len != 0 && payload->policies) { + struct tpm2_policies *pols; + static u8 *scratch; + int i; + bool found = false; + + pols = payload->policies; + + /* make sure it's not already in policy */ + for (i = 0; i < pols->count; i++) { + if (pols->code[i] == TPM2_CC_POLICY_AUTHVALUE) { + found = true; + break; + } + } + + if (!found) { + i = pols->count++; + scratch = pols->policies[i - 1] + pols->len[i - 1]; + /* the TPM2_PolicyPassword command has no payload */ + pols->policies[i] = scratch; + pols->len[i] = 0; + pols->code[i] = TPM2_CC_POLICY_AUTHVALUE; + } + } + if (payload->policies) { rc = tpm2_generate_policy_digest(payload->policies, options->hash,