From patchwork Thu Nov 3 18:01:09 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Evan Green X-Patchwork-Id: 13030793 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 133FCC4167B for ; Thu, 3 Nov 2022 18:04:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230254AbiKCSEt (ORCPT ); Thu, 3 Nov 2022 14:04:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37546 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229485AbiKCSEE (ORCPT ); Thu, 3 Nov 2022 14:04:04 -0400 Received: from mail-pj1-x1033.google.com (mail-pj1-x1033.google.com [IPv6:2607:f8b0:4864:20::1033]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7581A22BF6 for ; Thu, 3 Nov 2022 11:01:38 -0700 (PDT) Received: by mail-pj1-x1033.google.com with SMTP id gw22so2394838pjb.3 for ; Thu, 03 Nov 2022 11:01:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=lM9Z5v7Eu604CuNLTlsjSA95eezHukKIbUcTBhCY+mI=; b=CvFb2x1b3z+i8giCOFLIxOTr2h/EG7j7EOr7ZFJmGhsDpF8OGa6M8BuPcydgaJdIwN A12osLRgjAjuT+xh6XMrP3FqWCEwBgabYCyexK4WkbweBlnA/aMbv771mWFp8ujR+YLR SFcZhIMdAV5+Bbt+pF9eqILuLuAuvFSKVHTc8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=lM9Z5v7Eu604CuNLTlsjSA95eezHukKIbUcTBhCY+mI=; b=230MgxRMHYLbm5tIvPZrsqcFTntOCVXN0d0MezaPEQfr5A/OuFcAs83ztoYzwI5dyf /MLpd+ful+W2t5lh2JlRe+IPYMQCGWP9Gr6ikh9FsUK/4ZAjWO4k6xKH02PmQXaLEdFd ovSvC8oNUzYXNKc6GKFgvc6FBVpcTWuleRR/fr9ykDq+iBSCQlxDBdqsJBLSaWrsFWGp gAR6ZtI6Oc/VoMSijKYUjDJZXfZVhMj9hcux2ikixIA9I7PK7SKwOU0H603HiNMPAydA YBa8xzlEvBwroDPfMOa2sijGTGJ8g097f+eHZ+bLIVPzI6PKWbRNQFZGFvgabLfW+GKE PEeg== X-Gm-Message-State: ACrzQf0VX6bpctZRpeXp9/lJN0V+BdeJ4nuAMKv+3DSF7UaZMEfHL/Jy +UgA/Jfdkxa+4rSLpimyE16VYQ== X-Google-Smtp-Source: AMsMyM4BFtMIHZPkyPImjndEgL8twoWmXUd1CLFYolLyArfMGqdQQ5DZVSgLhAeK40Pvt2w0iVF0AA== X-Received: by 2002:a17:90b:1918:b0:213:d97c:c6c9 with SMTP id mp24-20020a17090b191800b00213d97cc6c9mr24352877pjb.198.1667498498208; Thu, 03 Nov 2022 11:01:38 -0700 (PDT) Received: from evgreen-glaptop.lan ([98.45.28.95]) by smtp.gmail.com with ESMTPSA id t12-20020a1709027fcc00b00177fb862a87sm1000277plb.20.2022.11.03.11.01.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Nov 2022 11:01:37 -0700 (PDT) From: Evan Green To: linux-kernel@vger.kernel.org Cc: corbet@lwn.net, linux-pm@vger.kernel.org, rjw@rjwysocki.net, gwendal@chromium.org, apronin@chromium.org, Pavel Machek , Kees Cook , Matthew Garrett , linux-integrity@vger.kernel.org, jejb@linux.ibm.com, zohar@linux.ibm.com, dlunev@google.com, Eric Biggers , Ben Boeckel , jarkko@kernel.org, Matthew Garrett , Matthew Garrett , Evan Green , Jason Gunthorpe , Peter Huewe , axelj Subject: [PATCH v4 01/11] tpm: Add support for in-kernel resetting of PCRs Date: Thu, 3 Nov 2022 11:01:09 -0700 Message-Id: <20221103105558.v4.1.I776854f47e3340cc2913ed4d8ecdd328048b73c3@changeid> X-Mailer: git-send-email 2.38.1.431.g37b22c650d-goog In-Reply-To: <20221103180120.752659-1-evgreen@chromium.org> References: <20221103180120.752659-1-evgreen@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: Matthew Garrett Add an internal command for resetting a PCR. This will be used by the encrypted hibernation code to set PCR23 to a known value. The hibernation code will seal the hibernation key with a policy specifying PCR23 be set to this known value as a mechanism to ensure that the hibernation key is genuine. But to do this repeatedly, resetting the PCR is necessary as well. Link: https://lore.kernel.org/lkml/20210220013255.1083202-2-matthewgarrett@google.com/ Signed-off-by: Matthew Garrett Signed-off-by: Evan Green --- Changes in v4: - Open code tpm2_pcr_reset implementation in tpm-interface.c (Jarkko) - Rename interface symbol to tpm2_pcr_reset, fix kerneldocs (Jarkko) Changes in v3: - Unify tpm1/2_pcr_reset prototypes (Jarkko) - Wait no, remove the TPM1 stuff altogether (Jarkko) - Remove extra From tag and blank in commit msg (Jarkko). drivers/char/tpm/tpm-interface.c | 47 ++++++++++++++++++++++++++++++++ drivers/char/tpm/tpm2-cmd.c | 7 ----- include/linux/tpm.h | 14 ++++++++++ 3 files changed, 61 insertions(+), 7 deletions(-) diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index 1621ce8187052c..886277b2654e3b 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -342,6 +342,53 @@ int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, } EXPORT_SYMBOL_GPL(tpm_pcr_extend); +/** + * tpm2_pcr_reset - Reset the specified PCR + * @chip: A &struct tpm_chip instance, %NULL for the default chip + * @pcr_idx: The PCR to be reset + * + * Return: Same as with tpm_transmit_cmd(), or ENOTTY for TPM1 devices. + */ +int tpm2_pcr_reset(struct tpm_chip *chip, u32 pcr_idx) +{ + struct tpm2_null_auth_area auth_area; + struct tpm_buf buf; + int rc; + + chip = tpm_find_get_ops(chip); + if (!chip) + return -ENODEV; + + if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) { + rc = -ENOTTY; + goto out; + } + + rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_RESET); + if (rc) + goto out; + + tpm_buf_append_u32(&buf, pcr_idx); + + auth_area.handle = cpu_to_be32(TPM2_RS_PW); + auth_area.nonce_size = 0; + auth_area.attributes = 0; + auth_area.auth_size = 0; + + tpm_buf_append_u32(&buf, sizeof(struct tpm2_null_auth_area)); + tpm_buf_append(&buf, (const unsigned char *)&auth_area, + sizeof(auth_area)); + + rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to reset a PCR"); + + tpm_buf_destroy(&buf); + +out: + tpm_put_ops(chip); + return rc; +} +EXPORT_SYMBOL_GPL(tpm2_pcr_reset); + /** * tpm_send - send a TPM command * @chip: a &struct tpm_chip instance, %NULL for the default chip diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c index 65d03867e114c5..303ce2ea02a4b0 100644 --- a/drivers/char/tpm/tpm2-cmd.c +++ b/drivers/char/tpm/tpm2-cmd.c @@ -216,13 +216,6 @@ int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx, return rc; } -struct tpm2_null_auth_area { - __be32 handle; - __be16 nonce_size; - u8 attributes; - __be16 auth_size; -} __packed; - /** * tpm2_pcr_extend() - extend a PCR value * diff --git a/include/linux/tpm.h b/include/linux/tpm.h index dfeb25a0362dee..70134e6551745f 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -219,6 +219,7 @@ enum tpm2_command_codes { TPM2_CC_HIERARCHY_CONTROL = 0x0121, TPM2_CC_HIERARCHY_CHANGE_AUTH = 0x0129, TPM2_CC_CREATE_PRIMARY = 0x0131, + TPM2_CC_PCR_RESET = 0x013D, TPM2_CC_SEQUENCE_COMPLETE = 0x013E, TPM2_CC_SELF_TEST = 0x0143, TPM2_CC_STARTUP = 0x0144, @@ -293,6 +294,13 @@ struct tpm_header { }; } __packed; +struct tpm2_null_auth_area { + __be32 handle; + __be16 nonce_size; + u8 attributes; + __be16 auth_size; +} __packed; + /* A string buffer type for constructing TPM commands. This is based on the * ideas of string buffer code in security/keys/trusted.h but is heap based * in order to keep the stack usage minimal. @@ -423,6 +431,7 @@ extern ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_buf *buf, size_t min_rsp_body_length, const char *desc); extern int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx, struct tpm_digest *digest); +extern int tpm2_pcr_reset(struct tpm_chip *chip, u32 pcr_idx); extern int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, struct tpm_digest *digests); extern int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen); @@ -440,6 +449,11 @@ static inline int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, return -ENODEV; } +static inline int tpm2_pcr_reset(struct tpm_chip *chip, int pcr_idx) +{ + return -ENODEV; +} + static inline int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, struct tpm_digest *digests) {