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Subject: Re: [PATCH v5 11/17] tpm: move TPM space code out of tpm_transmit()
To:     Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        linux-integrity@vger.kernel.org
Cc:     linux-security-module@vger.kernel.org,
        James Bottomley <James.Bottomley@HansenPartnership.com>,
        Tomas Winkler <tomas.winkler@intel.com>,
        Tadeusz Struk <tadeusz.struk@intel.com>,
        Stefan Berger <stefanb@linux.vnet.ibm.com>,
        Nayna Jain <nayna@linux.ibm.com>,
        Peter Huewe <peterhuewe@gmx.de>,
        Jason Gunthorpe <jgg@ziepe.ca>, Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        open list <linux-kernel@vger.kernel.org>
References: <20181108141541.12832-1-jarkko.sakkinen@linux.intel.com>
 <20181108141541.12832-12-jarkko.sakkinen@linux.intel.com>
From:   Stefan Berger <stefanb@linux.ibm.com>
Date:   Thu, 8 Nov 2018 10:16:54 -0500
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On 11/8/18 9:15 AM, Jarkko Sakkinen wrote:
> Prepare and commit TPM space before and after calling tpm_transmit()
> instead of doing that inside tpm_transmit(). After this change we can
> remove TPM_TRANSMIT_NESTED flag from tpm2_prepare_space() and
> tpm2_commit_space() and replace it with TPM_TRANSMIT_UNLOCKED.
>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
>   drivers/char/tpm/tpm-dev-common.c | 30 ++++++++++++++++++++++++++----
>   drivers/char/tpm/tpm-interface.c  | 29 +++--------------------------
>   drivers/char/tpm/tpm2-space.c     | 14 +++++++-------
>   3 files changed, 36 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
> index cbb0ee30b511..40c1cb09ebd2 100644
> --- a/drivers/char/tpm/tpm-dev-common.c
> +++ b/drivers/char/tpm/tpm-dev-common.c
> @@ -30,13 +30,35 @@ static DEFINE_MUTEX(tpm_dev_wq_lock);
>   static ssize_t tpm_dev_transmit(struct tpm_chip *chip, struct tpm_space *space,
>   				u8 *buf, size_t bufsiz)
>   {
> -	ssize_t ret;
> +	struct tpm_header *header = (void *)buf;
> +	ssize_t ret, len;
>
>   	mutex_lock(&chip->tpm_mutex);
> -	ret = tpm_transmit(chip, space, buf, bufsiz, TPM_TRANSMIT_UNLOCKED);
> -	mutex_unlock(&chip->tpm_mutex);
> +	ret = tpm2_prepare_space(chip, space, buf, bufsiz);
> +	/* If the command is not implemented by the TPM, synthesize a
> +	 * response with a TPM2_RC_COMMAND_CODE return for user-space.
> +	 */
> +	if (ret == -EOPNOTSUPP) {
> +		header->length = cpu_to_be32(sizeof(*header));
> +		header->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
> +		header->return_code = cpu_to_be32(TPM2_RC_COMMAND_CODE |
> +						  TSS2_RESMGR_TPM_RC_LAYER);
> +		ret = sizeof(*header);
> +	}
> +	if (ret)
> +		goto out_lock;
>
> -	return ret;
> +	len = tpm_transmit(chip, space, buf, bufsiz, TPM_TRANSMIT_UNLOCKED);
> +	if (len < 0)
> +		ret = len;
> +
> +	if (ret)
> +		tpm2_flush_space(chip);
> +	else
> +		ret = tpm2_commit_space(chip, space, buf, &len);
> +out_lock:
> +	mutex_unlock(&chip->tpm_mutex);
> +	return ret ? ret : len;
>   }
>
>   static void tpm_dev_async_work(struct work_struct *work)
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index a6ffd0960ae5..7bec03e46043 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -147,27 +147,12 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
>   		return -E2BIG;
>   	}
>
> -	rc = tpm2_prepare_space(chip, space, buf, bufsiz);
> -	/*
> -	 * If the command is not implemented by the TPM, synthesize a
> -	 * response with a TPM2_RC_COMMAND_CODE return for user-space.
> -	 */
> -	if (rc == -EOPNOTSUPP) {
> -		header->length = cpu_to_be32(sizeof(*header));
> -		header->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
> -		header->return_code = cpu_to_be32(TPM2_RC_COMMAND_CODE |
> -						  TSS2_RESMGR_TPM_RC_LAYER);
> -		return sizeof(*header);
> -	}
> -	if (rc)
> -		return rc;
> -
>   	rc = chip->ops->send(chip, buf, count);
>   	if (rc < 0) {
>   		if (rc != -EPIPE)
>   			dev_err(&chip->dev,
>   				"%s: tpm_send: error %d\n", __func__, rc);
> -		goto out_space;
> +		return rc;
>   	}
>
>   	if (chip->flags & TPM_CHIP_FLAG_IRQ)
> @@ -182,8 +167,7 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
>
>   		if (chip->ops->req_canceled(chip, status)) {
>   			dev_err(&chip->dev, "Operation Canceled\n");
> -			rc = -ECANCELED;
> -			goto out_space;
> +			return -ECANCELED;
>   		}
>
>   		tpm_msleep(TPM_TIMEOUT_POLL);
> @@ -192,8 +176,7 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
>
>   	chip->ops->cancel(chip);
>   	dev_err(&chip->dev, "Operation Timed out\n");
> -	rc = -ETIME;
> -	goto out_space;
> +	return -ETIME;
>
>   out_recv:
>   	len = chip->ops->recv(chip, buf, bufsiz);
> @@ -203,12 +186,6 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
>   	} else if (len < TPM_HEADER_SIZE || len != be32_to_cpu(header->length))
>   		rc = -EFAULT;
>
> -out_space:
> -	if (rc)
> -		tpm2_flush_space(chip);
> -	else
> -		rc = tpm2_commit_space(chip, space, buf, &len);
> -
>   	return rc ? rc : len;
>   }
>
> diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
> index f35ac941c3a4..9c009db15f88 100644
> --- a/drivers/char/tpm/tpm2-space.c
> +++ b/drivers/char/tpm/tpm2-space.c
> @@ -39,7 +39,7 @@ static void tpm2_flush_sessions(struct tpm_chip *chip, struct tpm_space *space)
>   	for (i = 0; i < ARRAY_SIZE(space->session_tbl); i++) {
>   		if (space->session_tbl[i])
>   			tpm2_flush_context_cmd(chip, space->session_tbl[i],
> -					       TPM_TRANSMIT_NESTED);
> +					       TPM_TRANSMIT_UNLOCKED);
>   	}
>   }
>
> @@ -84,7 +84,7 @@ static int tpm2_load_context(struct tpm_chip *chip, u8 *buf,
>   	tpm_buf_append(&tbuf, &buf[*offset], body_size);
>
>   	rc = tpm_transmit_cmd(chip, NULL, &tbuf, 4,
> -			      TPM_TRANSMIT_NESTED, NULL);
> +			      TPM_TRANSMIT_UNLOCKED, NULL);
>   	if (rc < 0) {
>   		dev_warn(&chip->dev, "%s: failed with a system error %d\n",
>   			 __func__, rc);
> @@ -133,7 +133,7 @@ static int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf,
>   	tpm_buf_append_u32(&tbuf, handle);
>
>   	rc = tpm_transmit_cmd(chip, NULL, &tbuf, 0,
> -			      TPM_TRANSMIT_NESTED, NULL);
> +			      TPM_TRANSMIT_UNLOCKED, NULL);
>   	if (rc < 0) {
>   		dev_warn(&chip->dev, "%s: failed with a system error %d\n",
>   			 __func__, rc);
> @@ -170,7 +170,7 @@ void tpm2_flush_space(struct tpm_chip *chip)
>   	for (i = 0; i < ARRAY_SIZE(space->context_tbl); i++)
>   		if (space->context_tbl[i] && ~space->context_tbl[i])
>   			tpm2_flush_context_cmd(chip, space->context_tbl[i],
> -					       TPM_TRANSMIT_NESTED);
> +					       TPM_TRANSMIT_UNLOCKED);
>
>   	tpm2_flush_sessions(chip, space);
>   }
> @@ -267,7 +267,7 @@ static int tpm2_map_command(struct tpm_chip *chip, u32 cc, u8 *cmd)
>   static int tpm_validate_command(struct tpm_chip *chip, struct tpm_space *space,
>   				const u8 *cmd, size_t len)
>   {
> -	const struct tpm_input_header *header = (const void *)cmd;
> +	const struct tpm_header *header = (const void *)cmd;


You'll have to move this...


>   	int i;
>   	u32 cc;
>   	u32 attrs;
> @@ -419,7 +419,7 @@ static int tpm2_map_response_header(struct tpm_chip *chip, u32 cc, u8 *rsp,
>
>   	return 0;
>   out_no_slots:
> -	tpm2_flush_context_cmd(chip, phandle, TPM_TRANSMIT_NESTED);
> +	tpm2_flush_context_cmd(chip, phandle, TPM_TRANSMIT_UNLOCKED);
>   	dev_warn(&chip->dev, "%s: out of slots for 0x%08X\n", __func__,
>   		 phandle);
>   	return -ENOMEM;
> @@ -507,7 +507,7 @@ static int tpm2_save_space(struct tpm_chip *chip)
>   			return rc;
>
>   		tpm2_flush_context_cmd(chip, space->context_tbl[i],
> -				       TPM_TRANSMIT_NESTED);
> +				       TPM_TRANSMIT_UNLOCKED);
>   		space->context_tbl[i] = ~0;
>   	}
>

The rest looks good.