[PATCH v3 2/8] ima: Switch to ima_hash_algo for boot aggregate

Mimi Zohar zohar at linux.ibm.com
Mon Mar 2 17:33:01 UTC 2020

On Mon, 2020-03-02 at 15:11 +0000, Roberto Sassu wrote:

> > Yes, preference is given to the IMA default algorithm, but it should
> > fall back to using SHA256 or SHA1, based on the TPM.
> Ok. The patch already does it even if the TPM version is not checked.
> For TPM 1.2, if the default algorithm is not SHA1 the patch will select
> the first PCR bank (SHA1).
> Should I send a new patch which explicitly checks the TPM version?

Checking the TPM version shouldn't be necessary.  The code currently
sets bank_idx to the HASH_ALGO_SHA256.  If instead of initializing
bank_idx to 0, initialize it to the nr_allocated_banks or -1.  As long
as the bank_idx value is the same as the initialized value, set the
bank_idx to HASH_ALGO_SHA1.

The subsequent bank_idx would then be limited to testing for the
initialized value.


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