Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Cristian Marussi <cristian.marussi@arm.com>
To:     linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc:     sudeep.holla@arm.com, cristian.marussi@arm.com
Subject: [PATCH 2/6] firmware: arm_scmi: Improve checks on .info_get operations
Date:   Wed, 17 Aug 2022 18:27:27 +0100
Message-Id: <20220817172731.1185305-3-cristian.marussi@arm.com>
In-Reply-To: <20220817172731.1185305-1-cristian.marussi@arm.com>
References: <20220817172731.1185305-1-cristian.marussi@arm.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

SCMI protocols abstract and expose a number of protocol specific resources
like clocks, sensors and so on: information about such specific domain
resources are generally exposed via an .info_get protocol operation.

Improve the sanity check on these .info_get operations where needed.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
 drivers/firmware/arm_scmi/clock.c   | 6 +++++-
 drivers/firmware/arm_scmi/sensors.c | 3 +++
 include/linux/scmi_protocol.h       | 4 ++--
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/arm_scmi/clock.c b/drivers/firmware/arm_scmi/clock.c
index 3ed7ae0d6781..96060bf90a24 100644
--- a/drivers/firmware/arm_scmi/clock.c
+++ b/drivers/firmware/arm_scmi/clock.c
@@ -450,9 +450,13 @@ static int scmi_clock_count_get(const struct scmi_protocol_handle *ph)
 static const struct scmi_clock_info *
 scmi_clock_info_get(const struct scmi_protocol_handle *ph, u32 clk_id)
 {
+	struct scmi_clock_info *clk;
 	struct clock_info *ci = ph->get_priv(ph);
-	struct scmi_clock_info *clk = ci->clk + clk_id;
 
+	if (clk_id >= ci->num_clocks)
+		return NULL;
+
+	clk = ci->clk + clk_id;
 	if (!clk->name[0])
 		return NULL;
 
diff --git a/drivers/firmware/arm_scmi/sensors.c b/drivers/firmware/arm_scmi/sensors.c
index 7288c6117838..7d0c7476d206 100644
--- a/drivers/firmware/arm_scmi/sensors.c
+++ b/drivers/firmware/arm_scmi/sensors.c
@@ -948,6 +948,9 @@ scmi_sensor_info_get(const struct scmi_protocol_handle *ph, u32 sensor_id)
 {
 	struct sensors_info *si = ph->get_priv(ph);
 
+	if (sensor_id >= si->num_sensors)
+		return NULL;
+
 	return si->sensors + sensor_id;
 }
 
diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index a193884ecf2b..4f765bc788ff 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -84,7 +84,7 @@ struct scmi_protocol_handle;
 struct scmi_clk_proto_ops {
 	int (*count_get)(const struct scmi_protocol_handle *ph);
 
-	const struct scmi_clock_info *(*info_get)
+	const struct scmi_clock_info __must_check *(*info_get)
 		(const struct scmi_protocol_handle *ph, u32 clk_id);
 	int (*rate_get)(const struct scmi_protocol_handle *ph, u32 clk_id,
 			u64 *rate);
@@ -466,7 +466,7 @@ enum scmi_sensor_class {
  */
 struct scmi_sensor_proto_ops {
 	int (*count_get)(const struct scmi_protocol_handle *ph);
-	const struct scmi_sensor_info *(*info_get)
+	const struct scmi_sensor_info __must_check *(*info_get)
 		(const struct scmi_protocol_handle *ph, u32 sensor_id);
 	int (*trip_point_config)(const struct scmi_protocol_handle *ph,
 				 u32 sensor_id, u8 trip_id, u64 trip_value);
-- 
2.32.0