On 11/4/20 6:26 PM, Ilias Apalodimas wrote:
> Hi Heinrich,
>
> On Wed, Nov 04, 2020 at 05:50:16PM +0100, Heinrich Schuchardt wrote:
>> On 04.11.20 16:56, Ilias Apalodimas wrote:
>>>>>
>>>>> u32 tpm2_get_capability(struct udevice *dev, u32 capability, u32
>>>>> property,
>>>>> - void *buf, size_t prop_count)
>>>>> + void *buf, size_t prop_count, bool get_count)
>>>>
>>>> The implementation would be more stable if we would derive the offset
>>>> from field property instead of adding get_count.
>>>>
>>>
>>> We are not defining the tpmv2 internal structures anywhere in U-Boot.
>>> That's why the code is doing static sizeof(uX) instead of using offsetof.
>>> In the EFI part of the patchset, I've done exaclty that.
>>> Working with offsets on well defined struct is better, but out of scope for
>>> this
>>> patchset imho.
>>> We can look into refactoring the generic tpmv2 code once I add the rest of
>>> the EFI
>>> protocol parts?
>>
>> Can't we add the structures that we need to tpm-v2.h and use their size
>> here?
>
> Yes we can, but the scope of the patch is adding EFI_TCG2_PROTOCOL, not
> re-factor the tpmv2
> code along the way.
> Since the only change on the existing code to support the functionality
> needed for the
> EFI_TCG2_PROTOCOL protocol is just 4 bytes on an existing buffer, can we
> stick to that and
> think of refactoring the tpm stuff afterwards?
You expect a TPML_PCR_SELECTION when capabilities is TPM_CAP_PCRS.
typedef struct {
UINT32 count;
TPMS_PCR_SELECTION pcrSelections[TPM2_NUM_PCR_BANKS];
} TPML_PCR_SELECTION;
Why do you have to skip over the UINT32 here?
You just have to define this one structure in preparation of patch 2 and
then you can correctly parse the response in your implementation of the
EFI protocol.
I suggest not to change tpm2_get_capability() at all.
Best regards
Heinrich
>
> Regards
> /Ilias
>>
>> Best regards
>>
>> Heinrich
>>
>>>
>>>>> {
>>>>> u8 command_v2[COMMAND_BUFFER_SIZE] = {
>>>>
>>>> Shouldn't COMMAND_BUFFER_SIZE be changed to something with TPM in the
>>>> name, e.g TPM_COMMAND_BUFFER_SIZE?
>>>>
>>>>> tpm_u16(TPM2_ST_NO_SESSIONS), /* TAG */
>>>>> @@ -181,13 +181,17 @@ u32 tpm2_get_capability(struct udevice *dev, u32
>>>>> capability, u32 property,
>>>>> if (ret)
>>>>> return ret;
>>>>>
>>>>> + /* When reading PCR properties we need the count */
>>>>> + properties_off = sizeof(u16) + sizeof(u32) + sizeof(u32) +
>>>>> + sizeof(u8) + sizeof(u32);
>>>>> /*
>>>>> * In the response buffer, the properties are located after the:
>>>>> * tag (u16), response size (u32), response code (u32),
>>>>> * YES/NO flag (u8), TPM_CAP (u32) and TPMU_CAPABILITIES (u32).
>>>>> */
>>>>
>>>> This comment should be above 'properties_off ='. 'get_count' related
>>>> field should be mentioned.
>>>
>>> Sure, I'll fix this
>>>
>>> Regards
>>> /Ilias
>>>>
>>>> Best regards
>>>>
>>>> Heinrich
>>>>
>>>>> - properties_off = sizeof(u16) + sizeof(u32) + sizeof(u32) +
>>>>> - sizeof(u8) + sizeof(u32) + sizeof(u32);
>>>>> + if (!get_count)
>>>>> + properties_off += sizeof(u32);
>>>>> +
>>>>> memcpy(buf, &response[properties_off], response_len - properties_off);
>>>>>
>>>>> return 0;
>>>>>
>>>>
>>
