Rajiv Andrade wrote:
> Hi Wyllys,
>
> Sorry for the delay...
>
>> Ex:
>> if (set_object_policy(hTPM, TSS_SECRET_MODE_POPUP, 0, NULL))
>> return (ERR_FAIL);
>>
>> /* new policy object */
>> ret = Tspi_Context_CreateObject(hContext, TSS_OBJECT_TYPE_POLICY,
>> TSS_POLICY_USAGE, &hNewPolicy);
>>
>> if (ret) {
>> print_error(ret, gettext("Create policy object"));
>> return (ERR_FAIL);
>> }
>> ret = Tspi_Policy_SetSecret(hNewPolicy, TSS_SECRET_MODE_POPUP,
>> 0, NULL);
>
> The bug is here, obj_policy_set_secret() down in the stack isn't
> prompting the user in case the it's a popup mode policy. We also can't
> pass through these layers the flag that tells if it's asking for a new
> password or not. Not a big issue though, can be solved including another
> (yes, one more) flag in the policy struct that informs if the policy is
> assigned to an object or not and that would be set when calling
> Tspi_Policy_AssignToObject.
Would that work for Tspi_ChangeAuth? The new policy isn't assigned to the
object until after the hash is computed (authsess_xsap_init) so when would
the user be prompted in that case?
>
>> if (ret) {
>> print_error(ret, gettext("Set policy object secret"));
>> return (ERR_FAIL);
>> }
>>
>> ret = Tspi_ChangeAuth(hTPM, NULL, hNewPolicy);
>> if (ret) {
>> print_error(ret, gettext("Change authorization"));
>> return (ERR_FAIL);
>> }
>> ...
>>
>>
>> As a test, I have hacked the code in changeauth_owner to do the following
>> at the very beginning:
>>
>> TCPA_SECRET secret;
>> TSS_HOBJECT hPolicy;
>> if ((result = obj_tpm_get_policy(hObjectToChange, TSS_POLICY_USAGE,
>> &hPolicy)))
>> return result;
>>
>> if ((result = obj_policy_get_secret(hPolicy, TR_SECRET_CTX_NEW,
>> &secret)))
>> return result;
>>
>> if ((result = obj_policy_get_secret(hNewPolicy, TR_SECRET_CTX_NEW,
>> &secret)))
>> return result;
>>
>> if ((result = authsess_xsap_init(tspContext, hObjectToChange,
>> hNewPolicy,
>> TSS_AUTH_POLICY_REQUIRED,
>> TPM_ORD_ChangeAuthOwner,
>> TPM_ET_OWNER, &xsap)))
>> ...
>>
>>
>>
>> In the above code the "secret" data is ignored. obj_policy_get_secret is
>> just being
>> called because it is the only way to trigger the call to popup_GetSecret,
>> the result
>> is irrelevant because the actual auth data gets extracted by
>> authsess_xsap_init.
>>
>> This does indeed prompt for 2 Passwords and the command then succeeds,
>> though I
>> don't think this is the correct solution. Also, doing it this way, the user
>> gets the
>> same prompt for both the current password and the new one so its not very
>> intuitive as to
>> which one is being prompted.
>>
>
> The popup string can be set with Tspi_SetAttribData(), as in
> testsuite/tcg/tspi/Tspi_SetAttribData01.c and the differentiation
> between a new password prompt and a current password one is made by
> means of that flag I mentioned above.
Yeah, I eventually figured that part out.
>
> I'm going to write/submit this code the day after tomorrow, let me know
> if there's any concern about it.
Concern noted above, but if the tests pass with your fix, Im satisfied.
-Wyllys
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