On Tue, 2024-02-13 at 12:13 -0500, James Bottomley wrote: > + /* unique: key specific; for ECC it is two points */ > + tpm_buf_append_u16(&template, 0); > + tpm_buf_append_u16(&template, 0); Shouldn't the points be 32 bytes each in size, filled with zeros? The TCP TPM 2.0 Provisioning Guidance defines the SRK Template as a diff on top of Template L-2 (for ECC keys) as defined in the EK Credential Profile 2.0 document. Template L-2 calls for the X and Y points to be of 32 bytes each, filled with zeros. The Provisioning Guidance does not call for zero- sized points. For example, let's create an ECC Endorsement Key using the standard template then print its name: tpm2_createek -G ecc -c /dev/null -u ./ek.pub tpm2_loadexternal -c n -u ./ek.pub Equivalently using tpm2_createprimary: perl -e 'print "\0"x64' | tpm2_createprimary -C e -o ./ek.pub -G ecc -a 'fixedtpm|fixedparent|sensitivedataorigin|adminwithpolicy|restricted|decrypt' -L 837197674484b3f81a90cc8d46a5d724fd52d76e06520b64f2a1da1b331469aa -u - tpm2_loadexternal -c n -u ./ek.pub You'll find that the key's public modulus matches that of the EK Certificate imprinted by the manufacturer, indicating we got the template correct. To generate a standard SRK key, the TCG TPM2 Provisioning Guidance states we should: 1. set userWithAuth, 2. clear adminWithPolicy 3. set noDA, and 4. clear the authorization policy. There's no mention of alterations to the unique field. Let's also create the key in the null hierarchy: perl -e 'print "\0"x64' | tpm2_createprimary -C n -o ./null.pub -G ecc -a 'fixedtpm|fixedparent|sensitivedataorigin|userwithauth|noda|restricted|decrypt' -u - tpm2_loadexternal -c n -u ./null.pub The name does not match the kernel's name for the null key.
