Re: [PATCH v2 04/13] vtpmmgr: Allow specifying srk_handle for TPM2

[Samuel Thibault <samuel.thibault@ens-lyon.org>]

Jason Andryuk, le jeu. 06 mai 2021 09:59:14 -0400, a ecrit:
> Bypass taking ownership of the TPM2 if an srk_handle is specified.
> 
> This srk_handle must be usable with Null auth for the time being.
> 
> Signed-off-by: Jason Andryuk <jandryuk@gmail.com>

Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

> ---
> v2: Use "=" seperator
> ---
>  docs/man/xen-vtpmmgr.7.pod |  7 +++++++
>  stubdom/vtpmmgr/init.c     | 11 ++++++++++-
>  2 files changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/docs/man/xen-vtpmmgr.7.pod b/docs/man/xen-vtpmmgr.7.pod
> index 875dcce508..3286954568 100644
> --- a/docs/man/xen-vtpmmgr.7.pod
> +++ b/docs/man/xen-vtpmmgr.7.pod
> @@ -92,6 +92,13 @@ Valid arguments:
>  
>  =over 4
>  
> +=item srk_handle=<HANDLE>
> +
> +Specify a srk_handle for TPM 2.0.  TPM 2.0 uses a key hierarchy, and
> +this allow specifying the parent handle for vtpmmgr to create its own
> +key under.  Using this option bypasses vtpmmgr trying to take ownership
> +of the TPM.
> +
>  =item owner_auth=<AUTHSPEC>
>  
>  =item srk_auth=<AUTHSPEC>
> diff --git a/stubdom/vtpmmgr/init.c b/stubdom/vtpmmgr/init.c
> index 1506735051..130e4f4bf6 100644
> --- a/stubdom/vtpmmgr/init.c
> +++ b/stubdom/vtpmmgr/init.c
> @@ -302,6 +302,11 @@ int parse_cmdline_opts(int argc, char** argv, struct Opts* opts)
>              goto err_invalid;
>           }
>        }
> +      else if(!strncmp(argv[i], "srk_handle=", 11)) {
> +         if(sscanf(argv[i] + 11, "%x", &vtpm_globals.srk_handle) != 1) {
> +            goto err_invalid;
> +         }
> +      }
>        else if(!strncmp(argv[i], "tpmdriver=", 10)) {
>           if(!strcmp(argv[i] + 10, "tpm_tis")) {
>              opts->tpmdriver = TPMDRV_TPM_TIS;
> @@ -586,7 +591,11 @@ TPM_RESULT vtpmmgr2_create(void)
>  {
>      TPM_RESULT status = TPM_SUCCESS;
>  
> -    TPMTRYRETURN(tpm2_take_ownership());
> +    if ( vtpm_globals.srk_handle == 0 ) {
> +        TPMTRYRETURN(tpm2_take_ownership());
> +    } else {
> +        tpm2_AuthArea_ctor(NULL, 0, &vtpm_globals.srk_auth_area);
> +    }
>  
>     /* create SK */
>      TPM2_Create_Params_out out;
> -- 
> 2.30.2
> 

-- 
Samuel
"...[Linux's] capacity to talk via any medium except smoke signals."
(By Dr. Greg Wettstein, Roger Maris Cancer Center)