In the Linux kernel, the following vulnerability has been resolved: ethtool: cmis: validate start_cmd_payload_size from module The CMIS fi

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

ethtool: cmis: validate start_cmd_payload_size from module

The CMIS firmware update code reads start_cmd_payload_size from
the module's FW Management Features CDB reply and uses it directly
as the byte count for memcpy. The destination buffer is 112 bytes
(ETHTOOL_CMIS_CDB_LPL_MAX_PL_LENGTH - 8). So a malicious
module (or corrupted response) can cause a OOB write later on in
cmis_fw_update_start_download().

Let's error out. If modules that expect longer LPL writes actually
exist we should revisit.

struct cmis_cdb_start_fw_download_pl's definition has to move,
no change there.