Received-SPF: pass (google.com: domain of linux-kernel+bounces-99508-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249;
Precedence: bulk
Mime-Version: 1.0
Content-Transfer-Encoding: quoted-printable
Content-Type: text/plain; charset=UTF-8
Date: Mon, 11 Mar 2024 22:25:29 +0200
Message-Id: <CZR7B45P71XS.53XNZD9FWZSL@kernel.org>
Cc: <linux-kernel@vger.kernel.org>, <rnsastry@linux.ibm.com>,
 <peterhuewe@gmx.de>, <viparash@in.ibm.com>, <devicetree@vger.kernel.org>,
 <jsnitsel@redhat.com>
Subject: Re: [RFC PATCH v2 3/3] tpm: of: If available use linux,sml-log to
 get the log and its size
From: "Jarkko Sakkinen" <jarkko@kernel.org>
To: "Stefan Berger" <stefanb@linux.ibm.com>, <mpe@ellerman.id.au>,
 <linux-integrity@vger.kernel.org>, <linuxppc-dev@lists.ozlabs.org>
References: <20240311132030.1103122-1-stefanb@linux.ibm.com>
 <20240311132030.1103122-4-stefanb@linux.ibm.com>
In-Reply-To: <20240311132030.1103122-4-stefanb@linux.ibm.com>

On Mon Mar 11, 2024 at 3:20 PM EET, Stefan Berger wrote:
> If linux,sml-log is available use it to get the TPM log rather than the
> pointer found in linux,sml-base. This resolves an issue on PowerVM and KV=
M
> on Power where after a kexec the memory pointed to by linux,sml-base may
> have become inaccessible or corrupted. Also, linux,sml-log has replaced
> linux,sml-base and linux,sml-size on these two platforms.
>
> Keep the handling of linux,sml-base/sml-size for powernv platforms that
> provide the two properties via skiboot.
>
> Fixes: c5df39262dd5 ("drivers/char/tpm: Add securityfs support for event =
log")
> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>

I'm worried about not being up to date and instead using "cached" values
when verifying anything from a security chip. Does this guarantee that
TPM log is corrupted and will not get updated somehow?

BR, Jarkko