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Message-Id: <22d2ce2e-6636-82ad-3099-5f947bc70e05@linux.vnet.ibm.com>
Date: Thu, 1 Jun 2017 20:34:31 -0400
From: Stefan Berger <stefanb@...ux.vnet.ibm.com>
To: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Cc: tpmdd-devel@...ts.sourceforge.net,
linux-security-module@...r.kernel.org,
linux-kernel@...r.kernel.org, jgunthorpe@...idianresearch.com
Subject: Re: [PATCH v6 2/3] tpm: vtpm_proxy: Implement request_locality
function.
On 05/24/2017 08:09 PM, Jarkko Sakkinen wrote:
> On Wed, May 24, 2017 at 07:03:27PM -0400, Stefan Berger wrote:
>> On 05/24/2017 06:21 PM, Jarkko Sakkinen wrote:
>>> On Wed, May 24, 2017 at 05:39:40PM -0400, Stefan Berger wrote:
>>>> Implement the request_locality function. To set the locality on the
>>>> backend we define vendor-specific TPM 1.2 and TPM 2 ordinals and send
>>>> a command to the backend to set the locality for the next commands.
>>>>
>>>> To avoid recursing into requesting the locality, we set the
>>>> TPM_TRANSMIT_RAW flag when calling tpm_transmit_cmd. To avoid recursing
>>>> into TPM 2 space related commands, we set the space parameter to NULL.
>>>>
>>>> Signed-off-by: Stefan Berger <stefanb@...ux.vnet.ibm.com>
>>>> ---
>>>> drivers/char/tpm/tpm-interface.c | 1 +
>>>> drivers/char/tpm/tpm_vtpm_proxy.c | 36 ++++++++++++++++++++++++++++++++++++
>>>> include/uapi/linux/vtpm_proxy.h | 4 ++++
>>>> 3 files changed, 41 insertions(+)
>>>>
>>>> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
>>>> index 2eacda2..876d45f 100644
>>>> --- a/drivers/char/tpm/tpm-interface.c
>>>> +++ b/drivers/char/tpm/tpm-interface.c
>>>> @@ -537,6 +537,7 @@ ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_space *space,
>>>> return 0;
>>>> }
>>>> +EXPORT_SYMBOL_GPL(tpm_transmit_cmd);
>>>> #define TPM_DIGEST_SIZE 20
>>>> #define TPM_RET_CODE_IDX 6
>>>> diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c b/drivers/char/tpm/tpm_vtpm_proxy.c
>>>> index 751059d..66024bf 100644
>>>> --- a/drivers/char/tpm/tpm_vtpm_proxy.c
>>>> +++ b/drivers/char/tpm/tpm_vtpm_proxy.c
>>>> @@ -371,6 +371,41 @@ static bool vtpm_proxy_tpm_req_canceled(struct tpm_chip *chip, u8 status)
>>>> return ret;
>>>> }
>>>> +static int vtpm_proxy_request_locality(struct tpm_chip *chip, int locality)
>>>> +{
>>>> + struct tpm_buf buf;
>>>> + int rc;
>>>> + const struct tpm_output_header *header;
>>>> +
>>>> + if (chip->flags & TPM_CHIP_FLAG_TPM2)
>>>> + rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS,
>>>> + TPM2_CC_SET_LOCALITY);
>>> I would always go with this branch.
>>>
>>>> + else
>>>> + rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND,
>>>> + TPM_ORD_SET_LOCALITY);
>>>> + if (rc)
>>>> + return rc;
>>>> + tpm_buf_append_u8(&buf, locality);
>>>> +
>>>> + rc = tpm_transmit_cmd(chip, NULL, buf.data, tpm_buf_length(&buf), 0,
>>>> + TPM_TRANSMIT_UNLOCKED | TPM_TRANSMIT_RAW,
>>>> + "attempting to set locality");
>>>> + if (rc < 0) {
>>>> + locality = rc;
>>>> + goto out;
>>>> + }
>>>> +
>>>> + header = (const struct tpm_output_header *)buf.data;
>>>> + rc = be32_to_cpu(header->return_code);
>>>> + if (rc)
>>>> + locality = -1;
>>>> +
>>>> +out:
>>>> + tpm_buf_destroy(&buf);
>>>> +
>>>> + return locality;
>>>> +}
>>>> +
>>>> static const struct tpm_class_ops vtpm_proxy_tpm_ops = {
>>>> .flags = TPM_OPS_AUTO_STARTUP,
>>>> .recv = vtpm_proxy_tpm_op_recv,
>>>> @@ -380,6 +415,7 @@ static const struct tpm_class_ops vtpm_proxy_tpm_ops = {
>>>> .req_complete_mask = VTPM_PROXY_REQ_COMPLETE_FLAG,
>>>> .req_complete_val = VTPM_PROXY_REQ_COMPLETE_FLAG,
>>>> .req_canceled = vtpm_proxy_tpm_req_canceled,
>>>> + .request_locality = vtpm_proxy_request_locality,
>>>> };
>>>> /*
>>>> diff --git a/include/uapi/linux/vtpm_proxy.h b/include/uapi/linux/vtpm_proxy.h
>>>> index a69e991..58ac73c 100644
>>>> --- a/include/uapi/linux/vtpm_proxy.h
>>>> +++ b/include/uapi/linux/vtpm_proxy.h
>>>> @@ -46,4 +46,8 @@ struct vtpm_proxy_new_dev {
>>>> #define VTPM_PROXY_IOC_NEW_DEV _IOWR(0xa1, 0x00, struct vtpm_proxy_new_dev)
>>>> +/* vendor specific commands to set locality */
>>>> +#define TPM2_CC_SET_LOCALITY 0x20001000
>>>> +#define TPM_ORD_SET_LOCALITY 0x20001000
>>>> +
>>>> #endif /* _UAPI_LINUX_VTPM_PROXY_H */
>>>> --
>>>> 2.4.3
>>> What practical benefit you get from these two constants? I understand
>>> the value range but not so much the redundant code.
>> If you want to change this, please go ahead and give it a sinle name.
>> For the code branches above I think that we should at least send a TPM 1.2
>> formatted command in case of TPM 1.2 and a TPM 2 formatted one in case of
>> TPM 2. It seems just 'proper.'
>>
>> Stefan
> Agreed. I will make these changes no need to send new series.
I pushed an update to the test suite, which may help the cause to accept
this series.
https://github.com/stefanberger/linux-vtpm-tests
Patch 3/3 should probably not return -EFAULT in case of the user trying
to send the SetLocality command via /dev/tpm%d but rather -EPIPE to get
the logging of the error suppressed, even though that doesn't seem to be
the right error code.
Stefan
>
> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
>
> /Jarkko
>
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