On Thu, 2020-05-14 at 04:11 +0300, Jarkko Sakkinen wrote:
> On Thu, 2020-05-07 at 16:11 -0700, James Bottomley wrote:
> > In TPM 1.2 an authorization was a 20 byte number. The spec actually
> > recommended you to hash variable length passwords and use the sha1
> > hash as the authorization. Because the spec doesn't require this
> > hashing, the current authorization for trusted keys is a 40 digit hex
> > number. For TPM 2.0 the spec allows the passing in of variable length
> > passwords and passphrases directly, so we should allow that in trusted
> > keys for ease of use. Update the 'blobauth' parameter to take this
> > into account, so we can now use plain text passwords for the keys.
> >
> > so before
> >
> > keyctl add trusted kmk "new 32 blobauth=f572d396fae9206628714fb2ce00f72e94f2258f"
> >
> > after we will accept both the old hex sha1 form as well as a new
> > directly supplied password:
> >
> > keyctl add trusted kmk "new 32 blobauth=hello keyhandle=81000001"
> >
> > Since a sha1 hex code must be exactly 40 bytes long and a direct
> > password must be 20 or less, we use the length as the discriminator
> > for which form is input.
> >
> > Note this is both and enhancement and a potential bug fix. The TPM
> > 2.0 spec requires us to strip leading zeros, meaning empyty
> > authorization is a zero length HMAC whereas we're currently passing in
> > 20 bytes of zeros. A lot of TPMs simply accept this as OK, but the
> > Microsoft TPM emulator rejects it with TPM_RC_BAD_AUTH, so this patch
> > makes the Microsoft TPM emulator work with trusted keys.
> >
> > Fixes: 0fe5480303a1 ("keys, trusted: seal/unseal with TPM 2.0 chips")
> > Signed-off-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
> > Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
>
> Have not checked yet the tail. Probably won't check before PR for v5.8
> is out.
>
> Just wondering would it hurt to merge everything up until this patch?
I.e. could land it also to the release.
/Jarkko
