From patchwork Mon Dec 30 17:37:56 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Bottomley X-Patchwork-Id: 11313559 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 0738E921 for ; Mon, 30 Dec 2019 17:40:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA2202053B for ; Mon, 30 Dec 2019 17:40:28 +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="FDRbw9pp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727340AbfL3Rk2 (ORCPT ); Mon, 30 Dec 2019 12:40:28 -0500 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:39318 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726602AbfL3Rk2 (ORCPT ); Mon, 30 Dec 2019 12:40:28 -0500 Received: from localhost (localhost [127.0.0.1]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id 4353F8EE15F; Mon, 30 Dec 2019 09:40:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=hansenpartnership.com; s=20151216; t=1577727628; bh=23Cn71eJx0AKyDSbpqORDAxWJucZcBbmg7D9H8pTp1Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FDRbw9ppeNvrvkJVFultComoD9jAQtOLOHKhkUAPxWml4psM5/DK8lioSmlCJ4IOj 1J3tK3AmR/LQrovwnFcx67VSc26PYWozC0oMvmCl6Cf9v3Tp7VC6A/c3KT3wMuntGo ggT4gXg+kiuh6YM/2R6QenC5+/b5vJdw+VZZfKdM= 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 bA641DOJ_PIz; Mon, 30 Dec 2019 09:40:28 -0800 (PST) Received: from jarvis.int.hansenpartnership.com (jarvis.ext.hansenpartnership.com [153.66.160.226]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id CE5A08EE07B; Mon, 30 Dec 2019 09:40:27 -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 3/9] security: keys: trusted fix tpm2 authorizations Date: Mon, 30 Dec 2019 09:37:56 -0800 Message-Id: <20191230173802.8731-4-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 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=f572d396fae9206628714fb2ce00f72e94f2258f" after: keyctl add trusted kmk "new 32 blobauth=hello keyhandle=81000001" 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. Signed-off-by: James Bottomley --- include/keys/trusted-type.h | 1 + security/keys/trusted-keys/trusted_tpm1.c | 24 +++++++++++++++++++----- security/keys/trusted-keys/trusted_tpm2.c | 9 +++++---- 3 files changed, 25 insertions(+), 9 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 d2c5ec1e040b..ef15b6cda6ec 100644 --- a/security/keys/trusted-keys/trusted_tpm1.c +++ b/security/keys/trusted-keys/trusted_tpm1.c @@ -781,12 +781,26 @@ 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) + /* + * 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; + } else if (tpm2 && + opt->blobauth_len <= sizeof(opt->blobauth)) { + memcpy(opt->blobauth, args[0].from, + opt->blobauth_len); + } else { return -EINVAL; + } break; case Opt_migratable: if (*args[0].from == '0') diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c index 08ec7f48f01d..11a331a94327 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -91,10 +91,11 @@ 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, TPM_DIGEST_SIZE); - tpm_buf_append(&buf, options->blobauth, TPM_DIGEST_SIZE); + 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, payload->key_len + 1); tpm_buf_append(&buf, payload->key, payload->key_len); tpm_buf_append_u8(&buf, payload->migratable); @@ -258,7 +259,7 @@ 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)