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From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: David Howells <dhowells@redhat.com>, Jarkko Sakkinen <jarkko@kernel.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
	linux-integrity@vger.kernel.org,  keyrings@vger.kernel.org,
	Andreas.Fuchs@infineon.com, James Prestwood <prestwoj@gmail.com>,
	David Woodhouse <dwmw2@infradead.org>,
	Eric Biggers <ebiggers@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	"open list:CRYPTO API" <linux-crypto@vger.kernel.org>,
	open list <linux-kernel@vger.kernel.org>,
	Peter Huewe <peterhuewe@gmx.de>, Jason Gunthorpe <jgg@ziepe.ca>,
	Mimi Zohar <zohar@linux.ibm.com>,
	Paul Moore <paul@paul-moore.com>,
	James Morris <jmorris@namei.org>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	"open list:SECURITY SUBSYSTEM"
	<linux-security-module@vger.kernel.org>
Subject: Re: [PATCH v2 4/6] KEYS: trusted: Move tpm2_key_decode() to the TPM driver
Date: Tue, 21 May 2024 17:59:18 -0400	[thread overview]
Message-ID: <239a52eb5ed3a6c891382b63d08fe7b264850d38.camel@HansenPartnership.com> (raw)
In-Reply-To: <336755.1716327854@warthog.procyon.org.uk>

On Tue, 2024-05-21 at 22:44 +0100, David Howells wrote:
> Jarkko Sakkinen <jarkko@kernel.org> wrote:
> 
> > On Tue May 21, 2024 at 9:18 PM EEST, James Bottomley wrote:
> > ...
> > You don't save a single byte of memory with any constant that
> > dictates the size requirements for multiple modules in two disjoint
> > subsystems.
> 
> I think James is just suggesting you replace your limit argument with
> a constant not that you always allocate that amount of memory.

Exactly.  All we use it for is the -E2BIG check to ensure user space
isn't allowed to run away with loads of kernel memory.

> What the limit should be, OTOH, is up for discussion, but PAGE_SIZE
> seems not unreasonable.

A page is fine currently (MAX_BLOB_SIZE is 512).  However, it may be
too small for some of the complex policies when they're introduced. 
I'm not bothered about what it currently is, I just want it to be able
to be increased easily when the time comes.

James


  reply	other threads:[~2024-05-21 21:59 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-21  3:16 [PATCH v2 0/6] KEYS: asymmetric: tpm2_key_rsa Jarkko Sakkinen
2024-05-21  3:16 ` [PATCH v2 1/6] crypto: rsa-pkcs1pad: export rsa1_asn_lookup() Jarkko Sakkinen
2024-05-21  3:16 ` [PATCH v2 2/6] lib: Expand asn1_encode_integer() to variable size integers Jarkko Sakkinen
2024-05-21  5:36   ` [EXTERNAL] " Bharat Bhushan
     [not found]     ` < <SN7PR18MB5314CFBD18B011F292809EBFE3EA2@SN7PR18MB5314.namprd18.prod.outlook.com>
2024-05-21  6:21       ` Jarkko Sakkinen
2024-05-21  3:16 ` [PATCH v2 3/6] tpm: Export tpm2_load_context() Jarkko Sakkinen
2024-05-21  3:16 ` [PATCH v2 4/6] KEYS: trusted: Move tpm2_key_decode() to the TPM driver Jarkko Sakkinen
2024-05-21 18:18   ` James Bottomley
2024-05-21 21:17     ` Jarkko Sakkinen
2024-05-21 21:44     ` David Howells
2024-05-21 21:59       ` James Bottomley [this message]
2024-05-21 22:45         ` Jarkko Sakkinen
2024-05-21 22:59           ` Jarkko Sakkinen
2024-05-21 22:42       ` Jarkko Sakkinen
2024-05-21  3:16 ` [PATCH v2 5/6] tpm: tpm2_key: Extend parser to TPM_LoadableKey Jarkko Sakkinen
2024-05-21  5:47   ` [EXTERNAL] " Bharat Bhushan
     [not found]     ` < <SN7PR18MB53140F4341BC441C1C11586EE3EA2@SN7PR18MB5314.namprd18.prod.outlook.com>
2024-05-21  7:13       ` Jarkko Sakkinen
2024-05-21  3:16 ` [PATCH v2 6/6] keys: asymmetric: ASYMMETRIC_TPM2_KEY_RSA_SUBTYPE Jarkko Sakkinen
2024-05-21  7:25   ` [EXTERNAL] " Bharat Bhushan
     [not found]     ` < <SN7PR18MB531494159D3996799475209DE3EA2@SN7PR18MB5314.namprd18.prod.outlook.com>
2024-05-21  7:38       ` Jarkko Sakkinen

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