⚪ HID: hyperv: validate initial device info bounds (Linux Linux)

Description

In the Linux kernel, the following vulnerability has been resolved: HID: hyperv: validate initial device info bounds The Hyper-V synthetic HID host supplies SYNTH_HID_INITIAL_DEVICE_INFO messages that contain a HID descriptor followed by the report descriptor bytes. mousevsc_on_receive_device_info() trusts bLength and wDescriptorLength without checking that the received packet contains both byte ranges. A malformed host or backend message can therefore make the guest read past the received VMBus packet while copying the report descriptor. Pass the received initial-device-info size into the parser and reject descriptor lengths that exceed the packet. Impact: A malicious Hyper-V host or backend can crash a guest by sending a short initial device-info message with an oversized HID report descriptor length.