On Thu, Dec 06, 2018 at 07:38:30PM +0100, Roberto Sassu wrote:
On 12/5/2018 1:14 AM, Jarkko Sakkinen wrote:
On Tue, Dec 04, 2018 at 09:21:38AM +0100, Roberto Sassu wrote:
The new tpm_bank_list structure has been preferred to the tpm_digest
structure, to let the caller specify the size of the digest (which may be
unknown to the TPM driver).
Why is that? Didn't previous commit query these?
Since the TPM driver pads/truncates the first digest passed by the
caller to extend PCRs for which no digest was provided, it must know
which amount of data it can use. It is possible that the algorithm of
the first digest is unknown for the TPM driver, if the caller of
tpm_pcr_extend() didn't check chip->allocated_banks.
By requiring that the caller passes also the digest size, this problem
does not arise. It seems reasonable to me to pass this information, as
the caller calculated the digest and it should know the digest size.
OK. I noticed something other things that look to alarming:
1. The function does not fail if alg_id is not found. This will go
2. The function does not fail if there is a mismatch with the digest