From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B6C883B5847 for ; Thu, 13 Aug 2026 11:33:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786620822; cv=none; b=PF0Df6SIz/CWIqcubu8NgzK840kIwhdtpsdWdsA10GQtdBalQoBG+RQxI+c6s8ZRiF0czVFhZhHzvlmJucqkc/5uyCgMxAp9qkU8PgYTFMNztRTvaPo61YJGjC5juZJhfmhgrKapgfXrkGz4n9cxcSREEqL7yqEwTuHQ+7/b0Yw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786620822; c=relaxed/simple; bh=aWLumprBGsoy72lRv8x68zkWu6mKc6gVWpLkhsfLpmM=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=r8+dymwjzWH2GXhoKXmV4RFmQ+rDPAQSH5hVhSWNO0W53v4Y5kL9bmsFYqWSi8oDxxllR5ggkR8kR+RZNLsrvCMURh46VD07LNXdPddtO8dnniU/dpvePn9c0vITdh9tYoZaHcgT0XYWvY0vg/4jnnu7Nfl/RKBIjbAXAgev2MQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SRCSlI7P; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="SRCSlI7P" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C09BF1F00A3A; Thu, 13 Aug 2026 11:33:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786620821; bh=y+zdQDNzy9XwsWlPqks3FdQJfc35rE02ceOkdYN/X4E=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=SRCSlI7P53oA4cwNrU5q0zW+NinY5tBKh8OsuWfm1M9+LWos/Yvr2AY1X4VA7QPEa LqX4BSwLKfTXaqf49rlQXDN/E+Pbf5+hVvDTbqy4kgy3TfHe0MN0eUbp807bRmPbRB AJuFeOdC6uhedFYYZf2xFdqsNgyAibiTc6pzqKMmzd3er3PJSfQjVLWG8eme5iHW33 Ay/AQJhV9USx2DHAsqZTepw2AFGqFXaDwgP6ifMGNYdbMe9V7VDYPFCpSRFTGZusfA As60PyduvXobDk4R6yg20vo2RgxUTZZHQMSVIRScobzdzSuZbDMRJcFePpljfYw5Ux wZBQ6LbgmsFhg== From: Sudeep Holla Date: Thu, 13 Aug 2026 12:33:04 +0100 Subject: [PATCH v3 9/9] firmware: arm_scmi: Validate PCC shared memory signature Precedence: bulk X-Mailing-List: arm-scmi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260813-acpi_scmi_pcc-v3-9-cb6b88b4ebb3@kernel.org> References: <20260813-acpi_scmi_pcc-v3-0-cb6b88b4ebb3@kernel.org> In-Reply-To: <20260813-acpi_scmi_pcc-v3-0-cb6b88b4ebb3@kernel.org> To: arm-scmi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kernel-team@meta.com Cc: Cristian Marussi , Breno Leitao X-Mailer: b4 0.15.2 Validate the PCC shared memory signature when setting up an SCMI PCC channel. Reject channels whose shared memory signature does not encode PCC_SIGNATURE combined with the PCC subspace ID, so misconfigured firmware is caught before the transport starts using the shared memory region. Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/transports/pcc.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/arm_scmi/transports/pcc.c b/drivers/firmware/arm_scmi/transports/pcc.c index 337d551e3ad8..0ead0ec77162 100644 --- a/drivers/firmware/arm_scmi/transports/pcc.c +++ b/drivers/firmware/arm_scmi/transports/pcc.c @@ -623,8 +623,11 @@ static void rx_callback(struct mbox_client *cl, void *m) } static int pcc_chan_validate_shmem(struct scmi_chan_info *cinfo, - struct scmi_pcc *smbox) + struct scmi_pcc *smbox, int ss_id) { + struct pcc_shared_mem __iomem *shmem = smbox->pchan->shmem; + u32 valid_signature = ss_id + PCC_SIGNATURE; + if (smbox->pchan->shmem_size < SCMI_PCC_SHMEM_OVERHEAD || smbox->pchan->shmem_size - SCMI_PCC_SHMEM_OVERHEAD < cinfo->max_msg_size) { @@ -632,6 +635,11 @@ static int pcc_chan_validate_shmem(struct scmi_chan_info *cinfo, return -ENOSPC; } + if (ioread32(&shmem->header.signature) != valid_signature) { + dev_err(cinfo->dev, "invalid PCC shared memory signature\n"); + return -EINVAL; + } + return 0; } @@ -667,7 +675,7 @@ static int pcc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev, return ret; } - ret = pcc_chan_validate_shmem(cinfo, smbox); + ret = pcc_chan_validate_shmem(cinfo, smbox, ss_id); if (ret) { pcc_mbox_free_channel(smbox->pchan); return ret; -- 2.43.0