From patchwork Sat Mar 17 01:22:34 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: James Bottomley X-Patchwork-Id: 10290593 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 ECA9360386 for ; Sat, 17 Mar 2018 01:22:37 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D2152289DD for ; Sat, 17 Mar 2018 01:22:37 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C472E28A47; Sat, 17 Mar 2018 01:22:37 +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 14FFA289DD for ; Sat, 17 Mar 2018 01:22:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753028AbeCQBWg (ORCPT ); Fri, 16 Mar 2018 21:22:36 -0400 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:54294 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753020AbeCQBWg (ORCPT ); Fri, 16 Mar 2018 21:22:36 -0400 Received: from localhost (localhost [127.0.0.1]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id 001618EE139; Fri, 16 Mar 2018 18:22:35 -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 3kORgNPI4IET; Fri, 16 Mar 2018 18:22:35 -0700 (PDT) Received: from [153.66.254.194] (unknown [50.35.65.221]) (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 A4FB88EE0DF; Fri, 16 Mar 2018 18:22:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=hansenpartnership.com; s=20151216; t=1521249755; bh=p726XAh323KJUetv1Ck1ErbhPZtgcjZLZelbsUxTwDo=; h=Subject:From:To:Cc:Date:From; b=WKRv6Tf/zgnDDILdfiDfoiaeUQFng7iMaieO4ZJQ67r3eGN1UgSJGf8hxWYkFOGSC bFWPqdaDy4O2hkYvsHAu9YNTjUgAd3eT4wEvS6I6rwu2X4wEd62T7TBQCBBg6+NE8t GggjlSuXzBjTVD9t+eNSsuHjqKfzE58eysEDnK7Y= Message-ID: <1521249754.12827.7.camel@HansenPartnership.com> Subject: [PATCH] tpm: add retry logic From: James Bottomley To: "linux-integrity@vger.kernel.org" Cc: Jarkko Sakkinen Date: Fri, 16 Mar 2018 18:22:34 -0700 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 --- 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 7c3380201960..1d25d1dca2f0 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_transmit_internal(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_transmit_internal 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_transmit_internal(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 b2547a11271a..c542f877cea7 100644 --- a/drivers/char/tpm/tpm.h +++ b/drivers/char/tpm/tpm.h @@ -113,6 +113,7 @@ 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 {