Re: [Linux-ima-devel] [PATCH v2 4/5] keys, trusted: modify arguments of tpm_pcr_extend()

[Mimi Zohar <zohar@linux.vnet.ibm.com>]

On Fri, 2017-05-05 at 16:21 +0200, Roberto Sassu wrote:
> pcrlock() has been modified to pass the correct arguments
> to tpm_pcr_extend(): the pointer of a tpm2_digest structure containing
> a random value generated by tpm_get_random() and the size of the array (1).

If the number of arguments is wrong, that means the patch that
introduced the change is not bi-sect safe.  (This comment is
applicable to patch 5/5 too.)

Mimi

> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> ---
>  security/keys/trusted.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/security/keys/trusted.c b/security/keys/trusted.c
> index 2ae31c5..3eb89e6 100644
> --- a/security/keys/trusted.c
> +++ b/security/keys/trusted.c
> @@ -377,15 +377,15 @@ static int trusted_tpm_send(const u32 chip_num, unsigned char *cmd,
>   */
>  static int pcrlock(const int pcrnum)
>  {
> -	unsigned char hash[SHA1_DIGEST_SIZE];
> +	struct tpm2_digest digestarg = {.alg_id = TPM2_ALG_SHA1};
>  	int ret;
> 
>  	if (!capable(CAP_SYS_ADMIN))
>  		return -EPERM;
> -	ret = tpm_get_random(TPM_ANY_NUM, hash, SHA1_DIGEST_SIZE);
> +	ret = tpm_get_random(TPM_ANY_NUM, digestarg.digest, SHA1_DIGEST_SIZE);
>  	if (ret != SHA1_DIGEST_SIZE)
>  		return ret;
> -	return tpm_pcr_extend(TPM_ANY_NUM, pcrnum, hash) ? -EINVAL : 0;
> +	return tpm_pcr_extend(TPM_ANY_NUM, pcrnum, 1, &digestarg) ? -EINVAL : 0;
>  }
> 
>  /*