From: Jarkko Sakkinen <jarkko@kernel.org>
To: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: linux-kernel@vger.kernel.org, keyrings@vger.kernel.org,
Stefan Berger <stefanb@linux.ibm.com>,
Jarkko Sakkinen <jarkko.sakkinen@opinsys.com>,
Peter Huewe <peterhuewe@gmx.de>, Jason Gunthorpe <jgg@ziepe.ca>,
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:TPM DEVICE DRIVER" <linux-integrity@vger.kernel.org>,
"open list:SECURITY SUBSYSTEM"
<linux-security-module@vger.kernel.org>
Subject: Re: [PATCH v4] tpm: Managed allocations for tpm_buf instances
Date: Thu, 3 Jul 2025 01:39:34 +0300 [thread overview]
Message-ID: <aGW1JvClZ4lRaaqB@kernel.org> (raw)
In-Reply-To: <7316e17a4d8dba36a4a773f87dc4f516697dd402.camel@HansenPartnership.com>
On Tue, Jul 01, 2025 at 10:51:55PM -0400, James Bottomley wrote:
> On Tue, 2025-07-01 at 17:51 +0300, Jarkko Sakkinen wrote:
> > Repeal and replace tpm_buf_init() and tpm_buf_init_sized() with
> > tpm_buf_alloc(), which returns a buffer of memory with the struct
> > tpm_buf header at the beginning of the returned buffer. This leaves
> > 4090 bytes of free space for the payload.
>
> Shouldn't this be accounted for in tpm_buf_append()? right now it will
> let us run off the end of the allocation by six bytes before it signals
> overflow because it's checking final length against PAGE_SIZE not
> PAGE_SIZE - sizeof(struct tpm_buf). I realise this should be an
> impossible condition in production, but it's useful for debugging so we
> should be accurate about it to avoid hard to detect bugs.
Fully agree. Thanks for pointing this out!
>
> Regards,
>
> James
>
BR, Jarkko
next prev parent reply other threads:[~2025-07-02 22:39 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-01 14:51 [PATCH v4] tpm: Managed allocations for tpm_buf instances Jarkko Sakkinen
2025-07-01 21:42 ` Stefan Berger
2025-07-02 22:38 ` Jarkko Sakkinen
2025-07-02 2:51 ` James Bottomley
2025-07-02 22:39 ` Jarkko Sakkinen [this message]
2025-07-02 12:57 ` Jason Gunthorpe
2025-07-02 22:42 ` Jarkko Sakkinen
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