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From: Jarkko Sakkinen <jarkko@kernel.org>
To: Guanglei Zhu <zhugl3@xiaopeng.com>
Cc: peterhuewe@gmx.de, jgg@ziepe.ca, linux-integrity@vger.kernel.org,
	linux-kernel@vger.kernel.org, liuc63@xiaopeng.com
Subject: Re: [PATCH] tpm: eventlog: check the payload size before reading tag events
Date: Wed, 4 Nov 2026 13:02:19 +0200	[thread overview]
Message-ID: <ausQu4DY8WARe_2j@kernel.org> (raw)
In-Reply-To: <20261104025809.787723-1-zhugl3@xiaopeng.com>

On Wed, Nov 04, 2026 at 10:58:09AM +0800, Guanglei Zhu wrote:
> The legacy PC Client spec defines the EV_EVENT_TAG payload as a
> TCPA_PC_EVENT: event_id, event_size and event-type-specific data.
> A conformant entry carries the 8-byte header, and the hash-type
> ids carry a full digest.
> 
> The catch is that the log is an ACPI table the firmware leaves in
> memory: the TPM never measures the log itself, so the kernel cannot
> tell a conformant log from a corrupted one.  The iterators already
> work on that assumption - they stop once the declared event_size
> runs past the buffer end - and this check applies the same rule to
> what the EVENT_TAG branch reads off the payload.

Yeah, this is exactly what I wanted to know. Could you refine the
patch and send a new version with this?

It's really good stuff to have in the commit log when looking back
at old changes.


Br, Jarkko

  reply	other threads:[~2026-11-04 11:02 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-11-03  8:41 [PATCH] tpm: eventlog: check the payload size before reading tag events Guanglei Zhu
2026-11-03 13:00 ` Jarkko Sakkinen
2026-11-04  2:58   ` Guanglei Zhu
2026-11-04 11:02     ` Jarkko Sakkinen [this message]
2026-11-04 11:26       ` [PATCH v2] " Guanglei Zhu

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