From patchwork Wed Mar 21 18:43:48 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: James Bottomley X-Patchwork-Id: 10300015 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 710E960386 for ; Wed, 21 Mar 2018 18:43:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6F33028C81 for ; Wed, 21 Mar 2018 18:43:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 640B629897; Wed, 21 Mar 2018 18:43:51 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CB57128C81 for ; Wed, 21 Mar 2018 18:43:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752813AbeCUSnu (ORCPT ); Wed, 21 Mar 2018 14:43:50 -0400 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:41684 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752812AbeCUSnt (ORCPT ); Wed, 21 Mar 2018 14:43:49 -0400 Received: from localhost (localhost [127.0.0.1]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id 80FE58EE4F1; Wed, 21 Mar 2018 11:43:49 -0700 (PDT) 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 2teNgv5Eg32k; Wed, 21 Mar 2018 11:43:49 -0700 (PDT) Received: from [172.20.3.211] (unknown [74.113.218.50]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by bedivere.hansenpartnership.com (Postfix) with ESMTPSA id 351468EE0C7; Wed, 21 Mar 2018 11:43:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=hansenpartnership.com; s=20151216; t=1521657829; bh=qS4Fium0tO0eU4n1ht7/Em9SZ7OBSWRibrAx1aTG2D0=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=DPTZXj4Hn+TllNecl2/4jUJrLuiJOAdV61HWENDinysDsPTK6an0Kj9jN8iPlJcN7 oY78FtHxATa6an27jGJDelpacyUvBJXWozCQnLMasbhEd+3sknQvY38wkL+ud9KSqB RSL6GlTlU03F4cs6F4ungFKUS+QyIQqyJocxHRbU= Message-ID: <1521657828.6397.19.camel@HansenPartnership.com> Subject: [PATCH v2 1/2] tpm: add retry logic From: James Bottomley To: Jarkko Sakkinen Cc: "linux-integrity@vger.kernel.org" Date: Wed, 21 Mar 2018 11:43:48 -0700 In-Reply-To: <1521657747.6397.18.camel@HansenPartnership.com> References: <1521657747.6397.18.camel@HansenPartnership.com> X-Mailer: Evolution 3.20.5 Mime-Version: 1.0 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP TPM2 can return TPM2_RC_RETRY to any command and when it does we get unexpected failures inside the kernel that surprise users (this is mostly observed in the trusted key handling code). The UEFI 2.6 spec has advice on how to handle this: The firmware SHALL not return TPM2_RC_RETRY prior to the completion of the call to ExitBootServices(). Implementer’s Note: the implementation of this function should check the return value in the TPM response and, if it is TPM2_RC_RETRY, resend the command. The implementation may abort if a sufficient number of retries has been done. So we follow that advice in our tpm_transmit() code using TPM2_DURATION_SHORT as the initial wait duration and TPM2_DURATION_LONG as the maximum wait time. This should fix all the in-kernel use cases and also means that user space TSS implementations don't have to have their own retry handling. Signed-off-by: James Bottomley Cc: stable@vger.kernel.org Reviewed-by: Jarkko Sakkinen Tested-by: Jarkko Sakkinen --- v2: renamed tpm_transmit_internal() to tpm_try_transmit() --- drivers/char/tpm/tpm-interface.c | 75 ++++++++++++++++++++++++++++++++-------- drivers/char/tpm/tpm.h | 1 + 2 files changed, 61 insertions(+), 15 deletions(-) diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index ddf7d937c77c..9e9bb62ae6b8 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -398,21 +398,10 @@ static void tpm_relinquish_locality(struct tpm_chip *chip) chip->locality = -1; } -/** - * tpm_transmit - Internal kernel interface to transmit TPM commands. - * - * @chip: TPM chip to use - * @space: tpm space - * @buf: TPM command buffer - * @bufsiz: length of the TPM command buffer - * @flags: tpm transmit flags - bitmap - * - * Return: - * 0 when the operation is successful. - * A negative number for system errors (errno). - */ -ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space, - u8 *buf, size_t bufsiz, unsigned int flags) +static ssize_t tpm_try_transmit(struct tpm_chip *chip, + struct tpm_space *space, + u8 *buf, size_t bufsiz, + unsigned int flags) { struct tpm_output_header *header = (void *)buf; int rc; @@ -550,6 +539,62 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space, } /** + * tpm_transmit - Internal kernel interface to transmit TPM commands. + * + * @chip: TPM chip to use + * @space: tpm space + * @buf: TPM command buffer + * @bufsiz: length of the TPM command buffer + * @flags: tpm transmit flags - bitmap + * + * A wrapper around tpm_try_transmit that handles TPM2_RC_RETRY + * returns from the TPM and retransmits the command after a delay up + * to a maximum wait of TPM2_DURATION_LONG. + * + * Note: TPM1 never returns TPM2_RC_RETRY so the retry logic is TPM2 + * only + * + * Return: + * the length of the return when the operation is successful. + * A negative number for system errors (errno). + */ +ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space, + u8 *buf, size_t bufsiz, unsigned int flags) +{ + struct tpm_output_header *header = (struct tpm_output_header *)buf; + /* space for header and handles */ + u8 save[TPM_HEADER_SIZE + 3*sizeof(u32)]; + unsigned int delay_msec = TPM2_DURATION_SHORT; + u32 rc = 0; + ssize_t ret; + const size_t save_size = min(space ? sizeof(save) : TPM_HEADER_SIZE, + bufsiz); + + /* + * Subtlety here: if we have a space, the handles will be + * transformed, so when we restore the header we also have to + * restore the handles. + */ + memcpy(save, buf, save_size); + + for (;;) { + ret = tpm_try_transmit(chip, space, buf, bufsiz, flags); + if (ret < 0) + break; + rc = be32_to_cpu(header->return_code); + if (rc != TPM2_RC_RETRY) + break; + delay_msec *= 2; + if (delay_msec > TPM2_DURATION_LONG) { + dev_err(&chip->dev, "TPM is in retry loop\n"); + break; + } + tpm_msleep(delay_msec); + memcpy(buf, save, save_size); + } + return ret; +} +/** * tpm_transmit_cmd - send a tpm command to the device * The function extracts tpm out header return code * diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index ab3861631d27..05967c1a1f32 100644 --- a/drivers/char/tpm/tpm.h +++ b/drivers/char/tpm/tpm.h @@ -112,6 +112,7 @@ enum tpm2_return_codes { TPM2_RC_COMMAND_CODE = 0x0143, TPM2_RC_TESTING = 0x090A, /* RC_WARN */ TPM2_RC_REFERENCE_H0 = 0x0910, + TPM2_RC_RETRY = 0x0922, }; enum tpm2_algorithms {