From patchwork Wed Nov 4 01:18:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 11879433 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 C07BC174A for ; Wed, 4 Nov 2020 01:18:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A463F22409 for ; Wed, 4 Nov 2020 01:18:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730292AbgKDBSY (ORCPT ); Tue, 3 Nov 2020 20:18:24 -0500 Received: from mail.kernel.org ([198.145.29.99]:49732 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728157AbgKDBSY (ORCPT ); Tue, 3 Nov 2020 20:18:24 -0500 Received: from kernel.org (83-245-197-237.elisa-laajakaista.fi [83.245.197.237]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7D068223EA; Wed, 4 Nov 2020 01:18:20 +0000 (UTC) Date: Wed, 4 Nov 2020 03:18:17 +0200 From: Jarkko Sakkinen To: linux-integrity@vger.kernel.org Cc: David Howells , Mimi Zohar , James Bottomley , Jarkko Sakkinen , stable@vger.kernel.org, "James E.J. Bottomley" , Kent Yoder , James Morris , "Serge E. Hallyn" , "H. Peter Anvin" , David Safford , "open list:KEYS-TRUSTED" , "open list:SECURITY SUBSYSTEM" , open list Subject: [PATCH v4 1/3,RESEND 2] KEYS: trusted: Fix incorrect handling of tpm_get_random() Message-ID: <20201104011817.GB20387@kernel.org> References: <20201013025156.111305-1-jarkko.sakkinen@linux.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201013025156.111305-1-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk List-ID: When tpm_get_random() was introduced, it defined the following API for the return value: 1. A positive value tells how many bytes of random data was generated. 2. A negative value on error. However, in the call sites the API was used incorrectly, i.e. as it would only return negative values and otherwise zero. Returning he positive read counts to the user space does not make any possible sense. Fix this by returning -EIO when tpm_get_random() returns a positive value. Fixes: 41ab999c80f1 ("tpm: Move tpm_get_random api into the TPM device driver") Cc: stable@vger.kernel.org Cc: Mimi Zohar Cc: "James E.J. Bottomley" Cc: David Howells Cc: Kent Yoder Signed-off-by: Jarkko Sakkinen --- security/keys/trusted-keys/trusted_tpm1.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c index b9fe02e5f84f..c7b1701cdac5 100644 --- a/security/keys/trusted-keys/trusted_tpm1.c +++ b/security/keys/trusted-keys/trusted_tpm1.c @@ -403,9 +403,12 @@ static int osap(struct tpm_buf *tb, struct osapsess *s, int ret; ret = tpm_get_random(chip, ononce, TPM_NONCE_SIZE); - if (ret != TPM_NONCE_SIZE) + if (ret < 0) return ret; + if (ret != TPM_NONCE_SIZE) + return -EIO; + tpm_buf_reset(tb, TPM_TAG_RQU_COMMAND, TPM_ORD_OSAP); tpm_buf_append_u16(tb, type); tpm_buf_append_u32(tb, handle); @@ -496,8 +499,12 @@ static int tpm_seal(struct tpm_buf *tb, uint16_t keytype, goto out; ret = tpm_get_random(chip, td->nonceodd, TPM_NONCE_SIZE); + if (ret < 0) + return ret; + if (ret != TPM_NONCE_SIZE) - goto out; + return -EIO; + ordinal = htonl(TPM_ORD_SEAL); datsize = htonl(datalen); pcrsize = htonl(pcrinfosize); @@ -601,9 +608,12 @@ static int tpm_unseal(struct tpm_buf *tb, ordinal = htonl(TPM_ORD_UNSEAL); ret = tpm_get_random(chip, nonceodd, TPM_NONCE_SIZE); + if (ret < 0) + return ret; + if (ret != TPM_NONCE_SIZE) { pr_info("trusted_key: tpm_get_random failed (%d)\n", ret); - return ret; + return -EIO; } ret = TSS_authhmac(authdata1, keyauth, TPM_NONCE_SIZE, enonce1, nonceodd, cont, sizeof(uint32_t), @@ -1013,8 +1023,12 @@ static int trusted_instantiate(struct key *key, case Opt_new: key_len = payload->key_len; ret = tpm_get_random(chip, payload->key, key_len); + if (ret < 0) + goto out; + if (ret != key_len) { pr_info("trusted_key: key_create failed (%d)\n", ret); + ret = -EIO; goto out; } if (tpm2)