From mboxrd@z Thu Jan 1 00:00:00 1970 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 AF634C433FE for ; Sat, 7 May 2022 19:52:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376438AbiEGT4O (ORCPT ); Sat, 7 May 2022 15:56:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38782 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233826AbiEGT4M (ORCPT ); Sat, 7 May 2022 15:56:12 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6085E101E6; Sat, 7 May 2022 12:52:24 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 02A8DB80839; Sat, 7 May 2022 19:52:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 039C4C385A6; Sat, 7 May 2022 19:52:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1651953141; bh=X/O4y/aRdXYaFetNBd9mMfz0q2LnvF4V1KFVjT57NfE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=RXkd/hckRQqHEB1FqapYuyS2+P8NmVLo57OzPwrzxOVK0WZn0nzFRhGXgvnN7Vuef 1PJTYqBsIRsYckOwtfiKCpFCa5BBkKSsfFcaDU46euo90WSw3ew4sh7y3v9W0Kyjf3 T6XSo/Rzk8K2JrIrF2q/qZhu1cCW3CzpCOPvQqQUU7gcG49ELMi4ucVf6Kt6Uie+gM azg67ZXatSFDwyo/YauiWHjeKx5ooTs1NbrG5sH/D1AKEZGWLoDvdpZn2AT3ydwDbw 3Kuj8nz4Z8Od89cah+KiDe0IbI554Rgh6SZExdUkvDVazickc6CLHt7nhk66OkDltt 6a5RM4d3Dg5Uw== Date: Sat, 7 May 2022 22:53:56 +0300 From: Jarkko Sakkinen To: Johannes Holland Cc: linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org, robh+dt@kernel.org, devicetree@vger.kernel.org, peterhuewe@gmx.de, jgg@ziepe.ca, krzysztof.kozlowski+dt@linaro.org Subject: Re: [PATCH v2 2/4] tpm: Add tpm_tis_verify_crc to the tpm_tis_phy_ops protocol layer Message-ID: References: <20220506170013.22598-1-johannes.holland@infineon.com> <20220506170013.22598-2-johannes.holland@infineon.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220506170013.22598-2-johannes.holland@infineon.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 06, 2022 at 07:00:13PM +0200, Johannes Holland wrote: > Other than SPI TPMs, I2C TPMs implement a CRC feature for command and > response blobs. Add CRC validation to the TIS protocol according to the > TCG PC Client Platform TPM Profile (PTP) specification for TPM 2.0 v1.04 > revision 14 > > The CRC is calculated over the entirety of the FIFO register. Since the > phy_ops layer is not aware when the core layer is done reading/writing > the FIFO, CRC verification must be triggered from the core layer. To > this end, add an optional phy_ops API call. > > Signed-off-by: Johannes Holland > --- > drivers/char/tpm/tpm_tis_core.c | 14 ++++++++++++++ > drivers/char/tpm/tpm_tis_core.h | 10 ++++++++++ > drivers/char/tpm/tpm_tis_i2c.c | 28 ++++++++++++++++++++++++++++ > 3 files changed, 52 insertions(+) > > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c > index dc56b976d816..f1c893a5a38f 100644 > --- a/drivers/char/tpm/tpm_tis_core.c > +++ b/drivers/char/tpm/tpm_tis_core.c > @@ -289,6 +289,7 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count) > int size = 0; > int status; > u32 expected; > + int rc; > > if (count < TPM_HEADER_SIZE) { > size = -EIO; > @@ -328,6 +329,13 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count) > goto out; > } > > + rc = tpm_tis_verify_crc(priv, (size_t)size, buf); > + if (rc < 0) { > + dev_err(&chip->dev, "Error crc mismatch for response.\n"); > + size = rc; > + goto out; > + } > + > out: > tpm_tis_ready(chip); > return size; > @@ -443,6 +451,12 @@ static int tpm_tis_send_main(struct tpm_chip *chip, const u8 *buf, size_t len) > if (rc < 0) > return rc; > > + rc = tpm_tis_verify_crc(priv, len, buf); > + if (rc < 0) { > + dev_err(&chip->dev, "Error crc mismatch for command.\n"); > + return rc; > + } > + > /* go and do it */ > rc = tpm_tis_write8(priv, TPM_STS(priv->locality), TPM_STS_GO); > if (rc < 0) > diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h > index 6c203f36b8a1..66a5a13cd1df 100644 > --- a/drivers/char/tpm/tpm_tis_core.h > +++ b/drivers/char/tpm/tpm_tis_core.h > @@ -121,6 +121,8 @@ struct tpm_tis_phy_ops { > u8 *result, enum tpm_tis_io_mode mode); > int (*write_bytes)(struct tpm_tis_data *data, u32 addr, u16 len, > const u8 *value, enum tpm_tis_io_mode mode); > + int (*verify_crc)(struct tpm_tis_data *data, size_t len, > + const u8 *value); > }; > > static inline int tpm_tis_read_bytes(struct tpm_tis_data *data, u32 addr, > @@ -188,6 +190,14 @@ static inline int tpm_tis_write32(struct tpm_tis_data *data, u32 addr, > return rc; > } > > +static inline int tpm_tis_verify_crc(struct tpm_tis_data *data, size_t len, > + const u8 *value) > +{ > + if (!data->phy_ops->verify_crc) > + return 0; > + return data->phy_ops->verify_crc(data, len, value); > +} > + > static inline bool is_bsw(void) > { > #ifdef CONFIG_X86 > diff --git a/drivers/char/tpm/tpm_tis_i2c.c b/drivers/char/tpm/tpm_tis_i2c.c > index 34d12f78e7ab..5bae8374b877 100644 > --- a/drivers/char/tpm/tpm_tis_i2c.c > +++ b/drivers/char/tpm/tpm_tis_i2c.c > @@ -24,6 +24,7 @@ > #include > #include > #include > +#include > #include > #include "tpm_tis_core.h" > > @@ -33,6 +34,7 @@ > #define TPM_I2C_INTERFACE_CAPABILITY 0x30 > #define TPM_I2C_DEVICE_ADDRESS 0x38 > #define TPM_I2C_DATA_CSUM_ENABLE 0x40 > +#define TPM_DATA_CSUM 0x44 > #define TPM_I2C_DID_VID 0x48 > #define TPM_I2C_RID 0x4C > > @@ -253,6 +255,24 @@ static int tpm_tis_i2c_write_bytes(struct tpm_tis_data *data, u32 addr, u16 len, > return 0; > } > > +static int tpm_tis_i2c_verify_crc(struct tpm_tis_data *data, size_t len, > + const u8 *value) > +{ > + u16 crc_tpm, crc_host; > + int rc; > + > + rc = tpm_tis_read16(data, TPM_DATA_CSUM, &crc_tpm); > + if (rc < 0) > + return rc; > + > + /* reflect crc result, regardless of host endianness */ > + crc_host = swab16(crc_ccitt(0, value, len)); > + if (crc_tpm != crc_host) > + return -EIO; > + > + return 0; > +} > + > static int init_guard_time(struct tpm_tis_i2c_phy *phy) > { > u32 i2c_caps; > @@ -286,12 +306,14 @@ static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_resume); > static const struct tpm_tis_phy_ops tpm_i2c_phy_ops = { > .read_bytes = tpm_tis_i2c_read_bytes, > .write_bytes = tpm_tis_i2c_write_bytes, > + .verify_crc = tpm_tis_i2c_verify_crc, > }; > > static int tpm_tis_i2c_probe(struct i2c_client *dev, > const struct i2c_device_id *id) > { > struct tpm_tis_i2c_phy *phy; > + const u8 crc_enable = 1; > const u8 locality = 0; > int ret; > > @@ -316,6 +338,12 @@ static int tpm_tis_i2c_probe(struct i2c_client *dev, > if (ret) > return ret; > > + ret = tpm_tis_i2c_write_bytes(&phy->priv, TPM_I2C_DATA_CSUM_ENABLE, > + sizeof(crc_enable), &crc_enable, > + TPM_TIS_PHYS_8); > + if (ret) > + return ret; > + > return tpm_tis_core_init(&dev->dev, &phy->priv, -1, &tpm_i2c_phy_ops, > NULL); > } > -- > 2.34.1 > This looks quite finished patch, hold on with ack tho because I'd like ack prepending patches first. BR, Jarkko