From d1ceb2b2324717fa30b44d56ef0c52813e239569 Mon Sep 17 00:00:00 2001 From: Tzung-Bi Shih Date: Thu, 2 Jul 2026 08:27:45 +0000 Subject: [PATCH] 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. Fixes: 145d59baff59 ("platform/chrome: cros_ec_sensorhub: Add FIFO support") Reviewed-by: Tomasz Figa Link: https://lore.kernel.org/r/20260702082745.1014968-1-tzungbi@kernel.org Signed-off-by: Tzung-Bi Shih --- drivers/platform/chrome/cros_ec_sensorhub_ring.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/platform/chrome/cros_ec_sensorhub_ring.c b/drivers/platform/chrome/cros_ec_sensorhub_ring.c index 64e9615ed6f4..92941924c347 100644 --- a/drivers/platform/chrome/cros_ec_sensorhub_ring.c +++ b/drivers/platform/chrome/cros_ec_sensorhub_ring.c @@ -825,8 +825,15 @@ static void cros_ec_sensorhub_ring_handler(struct cros_ec_sensorhub *sensorhub) sensorhub->msg->outsize = 1; sensorhub->msg->insize = fifo_info_length; - if (cros_ec_cmd_xfer_status(ec->ec_dev, sensorhub->msg) < 0) + ret = cros_ec_cmd_xfer_status(ec->ec_dev, sensorhub->msg); + if (ret < 0) goto error; + if (ret != fifo_info_length) { + dev_warn_ratelimited(sensorhub->dev, + "Mismatch read length: size %d - expected %d\n", + ret, fifo_info_length); + goto error; + } memcpy(fifo_info, &sensorhub->resp->fifo_info, fifo_info_length);