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

Mimi Zohar
2017-05-30T03:36:41Z

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;
> }
>
> /*