In the Linux kernel, the following vulnerability has been resolved: platform/chrome: sensorhub: Fix memory overread in ring handler `max_response` and `sensor_num` are read from different EC commands: - `max_response` is from cros_ec_…

Overview

In the Linux kernel, the following vulnerability has been resolved:

platform/chrome: sensorhub: Fix memory overread in ring handler

max_response and sensor_num are read from different EC commands:

• max_response is from cros_ec_get_proto_info(). ec_dev->max_response = info->max_response_packet_size - sizeof(struct ec_host_response);

• sensor_num is from cros_ec_get_sensor_count(). sensor_num = cros_ec_get_sensor_count(ec);

With a malfunctioning EC firmware, it is possible that the msg->insize (i.e., fifo_info_length in the context) could be clamped in cros_ec_cmd_xfer() because msg->insize is greater than max_response.

int fifo_info_length =
        sizeof(struct ec_response_motion_sense_fifo_info) +
        sizeof(u16) * sensorhub->sensor_num;

This means the number of read bytes could be less than expected. As a result, the subsequent memcpy() in cros_ec_sensorhub_ring_handler() overreads the resp->fifo_info buffer.

Check the return value of cros_ec_cmd_xfer_status() and abort if the number of bytes read does not match the expected length.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.