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Message-ID: <9dfeb6e3d568452ab1227484405b1fc221bd25c1.camel@HansenPartnership.com>
Subject: Re: [PATCH RESEND] KEYS: trusted: Use ASN.1 encoded OID
From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Jarkko Sakkinen <jarkko@kernel.org>, linux-integrity@vger.kernel.org
Cc: keyrings@vger.kernel.org, David Woodhouse <dwmw2@infradead.org>, Eric
 Biggers <ebiggers@kernel.org>, Herbert Xu <herbert@gondor.apana.org.au>,
 "David S. Miller" <davem@davemloft.net>, Andrew Morton
 <akpm@linux-foundation.org>, Mimi Zohar <zohar@linux.ibm.com>, David
 Howells <dhowells@redhat.com>, Paul Moore <paul@paul-moore.com>, James
 Morris <jmorris@namei.org>, "Serge E. Hallyn" <serge@hallyn.com>, "open
 list:CRYPTO API" <linux-crypto@vger.kernel.org>,  open list
 <linux-kernel@vger.kernel.org>, "open list:SECURITY SUBSYSTEM"
 <linux-security-module@vger.kernel.org>
Date: Thu, 23 May 2024 11:30:47 -0400
In-Reply-To: <D1H2P674GFY0.3O8WYK2P1GZ2K@kernel.org>
References: <20240523131931.22350-1-jarkko@kernel.org>
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On Thu, 2024-05-23 at 16:54 +0300, Jarkko Sakkinen wrote:
> On Thu May 23, 2024 at 4:38 PM EEST, James Bottomley wrote:
> > On Thu, 2024-05-23 at 16:19 +0300, Jarkko Sakkinen wrote:
> > > There's no reason to encode OID_TPMSealedData at run-time, as it
> > > never changes.
> > > 
> > > Replace it with the encoded version, which has exactly the same
> > > size:
> > > 
> > >         67 81 05 0A 01 05
> > > 
> > > Include OBJECT IDENTIFIER (0x06) tag and length as the epilogue
> > > so
> > > that the OID can be simply copied to the blob.
> > 
> > This is true, but if we're going to do this, we should expand the
> > OID
> > registry functions (in lib/oid_registry.c) to do something like
> > encode_OID.  The registry already contains the hex above minus the
> > two
> > prefixes (which are easy to add).
> 
> Yes, I do agree with this idea, and I named variable the I named
> it to make it obvious that generation is possible.
> 
> It would be best to have a single source, which could be just
> a CSV file with entries like:
> 
> <Name>,<OID number>
> 
> And then in scripts/ there should be a script that takes this
> source and generates oid_registry.gen.{h,c}. The existing
> oid_registry.h should really just include oid_registry.gen.h
> then to make this transparent change.
> 
> And then in the series where OID's are encoded per-subsystem
> patch that takes pre-encoded OID into use.
> 
> Happy to review such patch set if it is pushed forward.

Heh, OK, since I'm the one who thinks it's quite easy, I'll give it a
go.

James