Merge tag 'scmi-fixes-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into arm/fixes

Arm SCMI firmware driver fixes for v5.19

Bunch of fixes to address:
1. Issues reported on RK3568 EVB1 and BPI-R2 pro platforms using SCMI.
   More checks were added to validate the firmware response but that
   resulted in breaking above platforms, so the checks are relaxed when
   for cases where there is no potential memory corruption issues.

2. Possible data leak by reading more than required length from the firmware.
   Recent addition of support for v3.1 extended names used larger buffers
   in the kernel and used their size to read response from the firmware even
   for cases where shorter formats are used. While that is mostly harmless
   except when firmware sends malformed non-NULL terminated buffers.

3. Possible issues sending unsupported commands to the firmware.
   SENSOR_AXIS_NAME_GET added in v3.1 needs to be used only if the firmware
   supports it. While the firmware conformant to the spec must return not
   supported error for any unsupported features, it is always safer to
   avoid issuing commands that are known to be unsupported.

4. Incorrect error propagation in scmi_voltage_descriptors_get.
   Since the return value is not reset for each iteration of the loop, the
   error value in the previous iteration will be carried for the current one.
   Fix that by not saving the return values into local variable.

5. Some warnings reported by cppcheck

* tag 'scmi-fixes-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux:
  firmware: arm_scmi: Fix incorrect error propagation in scmi_voltage_descriptors_get
  firmware: arm_scmi: Avoid using extended string-buffers sizes if not necessary
  firmware: arm_scmi: Fix SENSOR_AXIS_NAME_GET behaviour when unsupported
  firmware: arm_scmi: Remove all the unused local variables
  firmware: arm_scmi: Relax base protocol sanity checks on the protocol list

Link: https://lore.kernel.org/r/20220614100007.1029881-1-sudeep.holla@arm.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

8 files changed, 80 insertions, 46 deletions

diff --git a/drivers/firmware/arm_scmi/base.c b/drivers/firmware/arm_scmi/base.c
index 20fba7370f4e..a52f084a6a87 100644
--- a/drivers/firmware/arm_scmi/base.c
+++ b/drivers/firmware/arm_scmi/base.c
@@ -36,7 +36,7 @@ struct scmi_msg_resp_base_attributes {
 
 struct scmi_msg_resp_base_discover_agent {
 	__le32 agent_id;
-	u8 name[SCMI_MAX_STR_SIZE];
+	u8 name[SCMI_SHORT_NAME_MAX_SIZE];
 };
 
 
@@ -119,7 +119,7 @@ scmi_base_vendor_id_get(const struct scmi_protocol_handle *ph, bool sub_vendor)
 
 	ret = ph->xops->do_xfer(ph, t);
 	if (!ret)
-		memcpy(vendor_id, t->rx.buf, size);
+		strscpy(vendor_id, t->rx.buf, size);
 
 	ph->xops->xfer_put(ph, t);
 
@@ -221,11 +221,17 @@ scmi_base_implementation_list_get(const struct scmi_protocol_handle *ph,
 		calc_list_sz = (1 + (loop_num_ret - 1) / sizeof(u32)) *
 				sizeof(u32);
 		if (calc_list_sz != real_list_sz) {
-			dev_err(dev,
-				"Malformed reply - real_sz:%zd  calc_sz:%u\n",
-				real_list_sz, calc_list_sz);
-			ret = -EPROTO;
-			break;
+			dev_warn(dev,
+				 "Malformed reply - real_sz:%zd  calc_sz:%u  (loop_num_ret:%d)\n",
+				 real_list_sz, calc_list_sz, loop_num_ret);
+			/*
+			 * Bail out if the expected list size is bigger than the
+			 * total payload size of the received reply.
+			 */
+			if (calc_list_sz > real_list_sz) {
+				ret = -EPROTO;
+				break;
+			}
 		}
 
 		for (loop = 0; loop < loop_num_ret; loop++)
@@ -270,7 +276,7 @@ static int scmi_base_discover_agent_get(const struct scmi_protocol_handle *ph,
 	ret = ph->xops->do_xfer(ph, t);
 	if (!ret) {
 		agent_info = t->rx.buf;
-		strlcpy(name, agent_info->name, SCMI_MAX_STR_SIZE);
+		strscpy(name, agent_info->name, SCMI_SHORT_NAME_MAX_SIZE);
 	}
 
 	ph->xops->xfer_put(ph, t);
@@ -369,7 +375,7 @@ static int scmi_base_protocol_init(const struct scmi_protocol_handle *ph)
 	int id, ret;
 	u8 *prot_imp;
 	u32 version;
-	char name[SCMI_MAX_STR_SIZE];
+	char name[SCMI_SHORT_NAME_MAX_SIZE];
 	struct device *dev = ph->dev;
 	struct scmi_revision_info *rev = scmi_revision_area_get(ph);
 
diff --git a/drivers/firmware/arm_scmi/clock.c b/drivers/firmware/arm_scmi/clock.c
index 4d36a9a133d1..c7a83f6e38e5 100644
--- a/drivers/firmware/arm_scmi/clock.c
+++ b/drivers/firmware/arm_scmi/clock.c
@@ -153,7 +153,7 @@ static int scmi_clock_attributes_get(const struct scmi_protocol_handle *ph,
 	if (!ret) {
 		u32 latency = 0;
 		attributes = le32_to_cpu(attr->attributes);
-		strlcpy(clk->name, attr->name, SCMI_MAX_STR_SIZE);
+		strscpy(clk->name, attr->name, SCMI_SHORT_NAME_MAX_SIZE);
 		/* clock_enable_latency field is present only since SCMI v3.1 */
 		if (PROTOCOL_REV_MAJOR(version) >= 0x2)
 			latency = le32_to_cpu(attr->clock_enable_latency);
@@ -266,9 +266,7 @@ scmi_clock_describe_rates_get(const struct scmi_protocol_handle *ph, u32 clk_id,
 			      struct scmi_clock_info *clk)
 {
 	int ret;
-
 	void *iter;
-	struct scmi_msg_clock_describe_rates *msg;
 	struct scmi_iterator_ops ops = {
 		.prepare_message = iter_clk_describe_prepare_message,
 		.update_state = iter_clk_describe_update_state,
@@ -281,7 +279,8 @@ scmi_clock_describe_rates_get(const struct scmi_protocol_handle *ph, u32 clk_id,
 
 	iter = ph->hops->iter_response_init(ph, &ops, SCMI_MAX_NUM_RATES,
 					    CLOCK_DESCRIBE_RATES,
-					    sizeof(*msg), &cpriv);
+					    sizeof(struct scmi_msg_clock_describe_rates),
+					    &cpriv);
 	if (IS_ERR(iter))
 		return PTR_ERR(iter);
 
diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c
index 8f4051aca220..bbb0331801ff 100644
--- a/drivers/firmware/arm_scmi/perf.c
+++ b/drivers/firmware/arm_scmi/perf.c
@@ -252,7 +252,7 @@ scmi_perf_domain_attributes_get(const struct scmi_protocol_handle *ph,
 			dom_info->mult_factor =
 					(dom_info->sustained_freq_khz * 1000) /
 					dom_info->sustained_perf_level;
-		strlcpy(dom_info->name, attr->name, SCMI_MAX_STR_SIZE);
+		strscpy(dom_info->name, attr->name, SCMI_SHORT_NAME_MAX_SIZE);
 	}
 
 	ph->xops->xfer_put(ph, t);
@@ -332,7 +332,6 @@ scmi_perf_describe_levels_get(const struct scmi_protocol_handle *ph, u32 domain,
 {
 	int ret;
 	void *iter;
-	struct scmi_msg_perf_describe_levels *msg;
 	struct scmi_iterator_ops ops = {
 		.prepare_message = iter_perf_levels_prepare_message,
 		.update_state = iter_perf_levels_update_state,
@@ -345,7 +344,8 @@ scmi_perf_describe_levels_get(const struct scmi_protocol_handle *ph, u32 domain,
 
 	iter = ph->hops->iter_response_init(ph, &ops, MAX_OPPS,
 					    PERF_DESCRIBE_LEVELS,
-					    sizeof(*msg), &ppriv);
+					    sizeof(struct scmi_msg_perf_describe_levels),
+					    &ppriv);
 	if (IS_ERR(iter))
 		return PTR_ERR(iter);
 
diff --git a/drivers/firmware/arm_scmi/power.c b/drivers/firmware/arm_scmi/power.c
index 964882cc8747..356e83631664 100644
--- a/drivers/firmware/arm_scmi/power.c
+++ b/drivers/firmware/arm_scmi/power.c
@@ -122,7 +122,7 @@ scmi_power_domain_attributes_get(const struct scmi_protocol_handle *ph,
 		dom_info->state_set_notify = SUPPORTS_STATE_SET_NOTIFY(flags);
 		dom_info->state_set_async = SUPPORTS_STATE_SET_ASYNC(flags);
 		dom_info->state_set_sync = SUPPORTS_STATE_SET_SYNC(flags);
-		strlcpy(dom_info->name, attr->name, SCMI_MAX_STR_SIZE);
+		strscpy(dom_info->name, attr->name, SCMI_SHORT_NAME_MAX_SIZE);
 	}
 	ph->xops->xfer_put(ph, t);
 
diff --git a/drivers/firmware/arm_scmi/protocols.h b/drivers/firmware/arm_scmi/protocols.h
index 73304af5ec4a..c679f3fb8718 100644
--- a/drivers/firmware/arm_scmi/protocols.h
+++ b/drivers/firmware/arm_scmi/protocols.h
@@ -24,8 +24,6 @@
 
 #include <asm/unaligned.h>
 
-#define SCMI_SHORT_NAME_MAX_SIZE	16
-
 #define PROTOCOL_REV_MINOR_MASK	GENMASK(15, 0)
 #define PROTOCOL_REV_MAJOR_MASK	GENMASK(31, 16)
 #define PROTOCOL_REV_MAJOR(x)	((u16)(FIELD_GET(PROTOCOL_REV_MAJOR_MASK, (x))))
diff --git a/drivers/firmware/arm_scmi/reset.c b/drivers/firmware/arm_scmi/reset.c
index a420a9102094..673f3eb498f4 100644
--- a/drivers/firmware/arm_scmi/reset.c
+++ b/drivers/firmware/arm_scmi/reset.c
@@ -116,7 +116,7 @@ scmi_reset_domain_attributes_get(const struct scmi_protocol_handle *ph,
 		dom_info->latency_us = le32_to_cpu(attr->latency);
 		if (dom_info->latency_us == U32_MAX)
 			dom_info->latency_us = 0;
-		strlcpy(dom_info->name, attr->name, SCMI_MAX_STR_SIZE);
+		strscpy(dom_info->name, attr->name, SCMI_SHORT_NAME_MAX_SIZE);
 	}
 
 	ph->xops->xfer_put(ph, t);
diff --git a/drivers/firmware/arm_scmi/sensors.c b/drivers/firmware/arm_scmi/sensors.c
index 21e0ce89b153..7288c6117838 100644
--- a/drivers/firmware/arm_scmi/sensors.c
+++ b/drivers/firmware/arm_scmi/sensors.c
@@ -338,7 +338,6 @@ static int scmi_sensor_update_intervals(const struct scmi_protocol_handle *ph,
 					struct scmi_sensor_info *s)
 {
 	void *iter;
-	struct scmi_msg_sensor_list_update_intervals *msg;
 	struct scmi_iterator_ops ops = {
 		.prepare_message = iter_intervals_prepare_message,
 		.update_state = iter_intervals_update_state,
@@ -351,22 +350,28 @@ static int scmi_sensor_update_intervals(const struct scmi_protocol_handle *ph,
 
 	iter = ph->hops->iter_response_init(ph, &ops, s->intervals.count,
 					    SENSOR_LIST_UPDATE_INTERVALS,
-					    sizeof(*msg), &upriv);
+					    sizeof(struct scmi_msg_sensor_list_update_intervals),
+					    &upriv);
 	if (IS_ERR(iter))
 		return PTR_ERR(iter);
 
 	return ph->hops->iter_response_run(iter);
 }
 
+struct scmi_apriv {
+	bool any_axes_support_extended_names;
+	struct scmi_sensor_info *s;
+};
+
 static void iter_axes_desc_prepare_message(void *message,
 					   const unsigned int desc_index,
 					   const void *priv)
 {
 	struct scmi_msg_sensor_axis_description_get *msg = message;
-	const struct scmi_sensor_info *s = priv;
+	const struct scmi_apriv *apriv = priv;
 
 	/* Set the number of sensors to be skipped/already read */
-	msg->id = cpu_to_le32(s->id);
+	msg->id = cpu_to_le32(apriv->s->id);
 	msg->axis_desc_index = cpu_to_le32(desc_index);
 }
 
@@ -393,19 +398,21 @@ iter_axes_desc_process_response(const struct scmi_protocol_handle *ph,
 	u32 attrh, attrl;
 	struct scmi_sensor_axis_info *a;
 	size_t dsize = SCMI_MSG_RESP_AXIS_DESCR_BASE_SZ;
-	struct scmi_sensor_info *s = priv;
+	struct scmi_apriv *apriv = priv;
 	const struct scmi_axis_descriptor *adesc = st->priv;
 
 	attrl = le32_to_cpu(adesc->attributes_low);
+	if (SUPPORTS_EXTENDED_AXIS_NAMES(attrl))
+		apriv->any_axes_support_extended_names = true;
 
-	a = &s->axis[st->desc_index + st->loop_idx];
+	a = &apriv->s->axis[st->desc_index + st->loop_idx];
 	a->id = le32_to_cpu(adesc->id);
 	a->extended_attrs = SUPPORTS_EXTEND_ATTRS(attrl);
 
 	attrh = le32_to_cpu(adesc->attributes_high);
 	a->scale = S32_EXT(SENSOR_SCALE(attrh));
 	a->type = SENSOR_TYPE(attrh);
-	strscpy(a->name, adesc->name, SCMI_MAX_STR_SIZE);
+	strscpy(a->name, adesc->name, SCMI_SHORT_NAME_MAX_SIZE);
 
 	if (a->extended_attrs) {
 		unsigned int ares = le32_to_cpu(adesc->resolution);
@@ -444,10 +451,19 @@ iter_axes_extended_name_process_response(const struct scmi_protocol_handle *ph,
 					 void *priv)
 {
 	struct scmi_sensor_axis_info *a;
-	const struct scmi_sensor_info *s = priv;
+	const struct scmi_apriv *apriv = priv;
 	struct scmi_sensor_axis_name_descriptor *adesc = st->priv;
+	u32 axis_id = le32_to_cpu(adesc->axis_id);
 
-	a = &s->axis[st->desc_index + st->loop_idx];
+	if (axis_id >= st->max_resources)
+		return -EPROTO;
+
+	/*
+	 * Pick the corresponding descriptor based on the axis_id embedded
+	 * in the reply since the list of axes supporting extended names
+	 * can be a subset of all the axes.
+	 */
+	a = &apriv->s->axis[axis_id];
 	strscpy(a->name, adesc->name, SCMI_MAX_STR_SIZE);
 	st->priv = ++adesc;
 
@@ -458,21 +474,36 @@ static int
 scmi_sensor_axis_extended_names_get(const struct scmi_protocol_handle *ph,
 				    struct scmi_sensor_info *s)
 {
+	int ret;
 	void *iter;
-	struct scmi_msg_sensor_axis_description_get *msg;
 	struct scmi_iterator_ops ops = {
 		.prepare_message = iter_axes_desc_prepare_message,
 		.update_state = iter_axes_extended_name_update_state,
 		.process_response = iter_axes_extended_name_process_response,
 	};
+	struct scmi_apriv apriv = {
+		.any_axes_support_extended_names = false,
+		.s = s,
+	};
 
 	iter = ph->hops->iter_response_init(ph, &ops, s->num_axis,
 					    SENSOR_AXIS_NAME_GET,
-					    sizeof(*msg), s);
+					    sizeof(struct scmi_msg_sensor_axis_description_get),
+					    &apriv);
 	if (IS_ERR(iter))
 		return PTR_ERR(iter);
 
-	return ph->hops->iter_response_run(iter);
+	/*
+	 * Do not cause whole protocol initialization failure when failing to
+	 * get extended names for axes.
+	 */
+	ret = ph->hops->iter_response_run(iter);
+	if (ret)
+		dev_warn(ph->dev,
+			 "Failed to get axes extended names for %s (ret:%d).\n",
+			 s->name, ret);
+
+	return 0;
 }
 
 static int scmi_sensor_axis_description(const struct scmi_protocol_handle *ph,
@@ -481,12 +512,15 @@ static int scmi_sensor_axis_description(const struct scmi_protocol_handle *ph,
 {
 	int ret;
 	void *iter;
-	struct scmi_msg_sensor_axis_description_get *msg;
 	struct scmi_iterator_ops ops = {
 		.prepare_message = iter_axes_desc_prepare_message,
 		.update_state = iter_axes_desc_update_state,
 		.process_response = iter_axes_desc_process_response,
 	};
+	struct scmi_apriv apriv = {
+		.any_axes_support_extended_names = false,
+		.s = s,
+	};
 
 	s->axis = devm_kcalloc(ph->dev, s->num_axis,
 			       sizeof(*s->axis), GFP_KERNEL);
@@ -495,7 +529,8 @@ static int scmi_sensor_axis_description(const struct scmi_protocol_handle *ph,
 
 	iter = ph->hops->iter_response_init(ph, &ops, s->num_axis,
 					    SENSOR_AXIS_DESCRIPTION_GET,
-					    sizeof(*msg), s);
+					    sizeof(struct scmi_msg_sensor_axis_description_get),
+					    &apriv);
 	if (IS_ERR(iter))
 		return PTR_ERR(iter);
 
@@ -503,7 +538,8 @@ static int scmi_sensor_axis_description(const struct scmi_protocol_handle *ph,
 	if (ret)
 		return ret;
 
-	if (PROTOCOL_REV_MAJOR(version) >= 0x3)
+	if (PROTOCOL_REV_MAJOR(version) >= 0x3 &&
+	    apriv.any_axes_support_extended_names)
 		ret = scmi_sensor_axis_extended_names_get(ph, s);
 
 	return ret;
@@ -598,7 +634,7 @@ iter_sens_descr_process_response(const struct scmi_protocol_handle *ph,
 			    SUPPORTS_AXIS(attrh) ?
 			    SENSOR_AXIS_NUMBER(attrh) : 0,
 			    SCMI_MAX_NUM_SENSOR_AXIS);
-	strscpy(s->name, sdesc->name, SCMI_MAX_STR_SIZE);
+	strscpy(s->name, sdesc->name, SCMI_SHORT_NAME_MAX_SIZE);
 
 	/*
 	 * If supported overwrite short name with the extended
diff --git a/drivers/firmware/arm_scmi/voltage.c b/drivers/firmware/arm_scmi/voltage.c
index 9d195d8719ab..eaa8d944926a 100644
--- a/drivers/firmware/arm_scmi/voltage.c
+++ b/drivers/firmware/arm_scmi/voltage.c
@@ -180,7 +180,6 @@ static int scmi_voltage_levels_get(const struct scmi_protocol_handle *ph,
 {
 	int ret;
 	void *iter;
-	struct scmi_msg_cmd_describe_levels *msg;
 	struct scmi_iterator_ops ops = {
 		.prepare_message = iter_volt_levels_prepare_message,
 		.update_state = iter_volt_levels_update_state,
@@ -193,7 +192,8 @@ static int scmi_voltage_levels_get(const struct scmi_protocol_handle *ph,
 
 	iter = ph->hops->iter_response_init(ph, &ops, v->num_levels,
 					    VOLTAGE_DESCRIBE_LEVELS,
-					    sizeof(*msg), &vpriv);
+					    sizeof(struct scmi_msg_cmd_describe_levels),
+					    &vpriv);
 	if (IS_ERR(iter))
 		return PTR_ERR(iter);
 
@@ -225,15 +225,14 @@ static int scmi_voltage_descriptors_get(const struct scmi_protocol_handle *ph,
 
 		/* Retrieve domain attributes at first ... */
 		put_unaligned_le32(dom, td->tx.buf);
-		ret = ph->xops->do_xfer(ph, td);
 		/* Skip domain on comms error */
-		if (ret)
+		if (ph->xops->do_xfer(ph, td))
 			continue;
 
 		v = vinfo->domains + dom;
 		v->id = dom;
 		attributes = le32_to_cpu(resp_dom->attr);
-		strlcpy(v->name, resp_dom->name, SCMI_MAX_STR_SIZE);
+		strscpy(v->name, resp_dom->name, SCMI_SHORT_NAME_MAX_SIZE);
 
 		/*
 		 * If supported overwrite short name with the extended one;
@@ -249,12 +248,8 @@ static int scmi_voltage_descriptors_get(const struct scmi_protocol_handle *ph,
 				v->async_level_set = true;
 		}
 
-		ret = scmi_voltage_levels_get(ph, v);
 		/* Skip invalid voltage descriptors */
-		if (ret)
-			continue;
-
-		ph->xops->reset_rx_to_maxsz(ph, td);
+		scmi_voltage_levels_get(ph, v);
 	}
 
 	ph->xops->xfer_put(ph, td);