Re: [PATCH 00/22] KEYS: Support TPM-wrapped key and crypto ops

From: Marcel Holtmann
Date: Fri Sep 28 2018 - 13:20:58 EST


Hi David,

>>>>> Yes. It shouldn't be much code, either. You still have to check for X.509
>>>>> DER since the kernel currently supports that.
>>>>
>>>> For reasons of backward compatibility, correct? The kernel also has
>>>> mscode.asn1 which we would need to support as well. Since we can't break
>>>> compatibility then perhaps this doesn't buy us a whole lot in the end.
>>>
>>> Don't worry about mscode - that's not an asymmetric key parser. That's only
>>> ever used directly from verify_pefile_signature().
>>>
>>> Currently, we have to retain support for DER-encoded X.509.
>>>
>>> But there's no reason we can't have a PEM parser that decodes the PEM and
>>> selects X.509, PKCS#8 or TPM based on the ascii header in that. PKCS#8 and
>>> TPM don't need to take DER directly.
>>
>> since we have to support DER-encoded anyway, can we get the current
>> patches merged (with fixes to the commit messages for the openssl
>> examples if needed) and then work on PEM support inside the kernel.
>> For me these seems to be two independent features. And in the current
>> form the patches have been tested and used.
>>
>> Or let me ask this differently, are there any objections to merging
>> these patches with just DER support?
>
> Let me rephrase that question slightly: Are we happy to have to make
> inferences from the ASN.1 structure, and in particular that a bare
> OCTET-STRING is a TPMv1 blob? I believe James ended up doing something
> somewhat more sensible for the TPMv2 blob so that might end up being
> OK...?

similar to Denisâ comment, I donât see an issue here with using DER encoding.

James, can you take this series into your -next tree?

Regards

Marcel