From: "Jarkko Sakkinen" <jarkko@kernel.org>
To: "Jarkko Sakkinen" <jarkko@kernel.org>,
"James Bottomley" <James.Bottomley@HansenPartnership.com>,
"David Howells" <dhowells@redhat.com>
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: Wed, 22 May 2024 01:59:56 +0300 [thread overview]
Message-ID: <D1FP21Y7J8QO.7JCTW22LRSXF@kernel.org> (raw)
In-Reply-To: <D1FOQSFNZ794.23R2JV1SD8X8W@kernel.org>
On Wed May 22, 2024 at 1:45 AM EEST, Jarkko Sakkinen wrote:
> On Wed May 22, 2024 at 12:59 AM EEST, James Bottomley wrote:
> > 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.
>
> Not true.
>
> It did return -EINVAL. This patch changes it to -E2BIG.
>
> >
> > > 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.
>
> MAX_BLOB_SIZE would be used to cap key blob, not the policy.
>
> And you are ignoring it yourself too in the driver.
Obviously policy is part of the key blob i.e. expected value for that.
... but that does not reduce space requirements to rsa asymmetric keys.
It increases them but I think at this point 8192 is good starting point.
And it cap can be scaled later.
Being a parameter also allows to have even kernel-command line or sysfs
parameter and stuff like that. It is robust not a bad choice.
BR, Jarkko
next prev parent reply other threads:[~2024-05-21 23:00 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
2024-05-21 22:45 ` Jarkko Sakkinen
2024-05-21 22:59 ` Jarkko Sakkinen [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=D1FP21Y7J8QO.7JCTW22LRSXF@kernel.org \
--to=jarkko@kernel.org \
--cc=Andreas.Fuchs@infineon.com \
--cc=James.Bottomley@HansenPartnership.com \
--cc=davem@davemloft.net \
--cc=dhowells@redhat.com \
--cc=dwmw2@infradead.org \
--cc=ebiggers@kernel.org \
--cc=herbert@gondor.apana.org.au \
--cc=jgg@ziepe.ca \
--cc=jmorris@namei.org \
--cc=keyrings@vger.kernel.org \
--cc=linux-crypto@vger.kernel.org \
--cc=linux-integrity@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=paul@paul-moore.com \
--cc=peterhuewe@gmx.de \
--cc=prestwoj@gmail.com \
--cc=serge@hallyn.com \
--cc=zohar@linux.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).