Re: [PATCH] KEYS: trusted_tpm2: Only check options->keyhandle for ASN.1

Jarkko Sakkinen
2024-05-25T15:15:48Z

On Sat May 25, 2024 at 4:42 PM EEST, James Bottomley wrote:
> On Sat, 2024-05-25 at 15:36 +0300, Jarkko Sakkinen wrote:
> > tpm2_load_cmd incorrectly checks options->keyhandle also for the
> > legacy format, as also implied by the inline comment. Check
> > options->keyhandle when ASN.1 is loaded.
>
> No that's not right. keyhandle must be specified for the old format,
> because it's just the two private/public blobs and doesn't know it's
> parent. Since tpm2_key_decode() always places the ASN.1 parent into
> options->keyhandle, the proposed new code is fully redundant (options-
> >keyhandle must be non zero if the ASN.1 parsed correctly) but it loses
> the check that the loader must specify it for the old format.
>
> What the comment above the code you removed means is that the keyhandle
> must be non zero here, either extracted from the ASN.1 for the new
> format or specified on the command line for the old.

My code change was plain direct to the word interpreation of the
comment.

So I just take the last paragraph of yours and instead fix the
misleading comment:

/*
* Keyhandle must be non zero here, either extracted from the ASN.1 for
* the new format or specified on the command line for the old.
*/

BR, Jarkko