CVE-2025-38249: Out-of-bounds Read

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

ALSA: usb-audio: Fix out-of-bounds read in snd_usb_get_audioformat_uac3()

In snd_usb_get_audioformat_uac3(), the length value returned from snd_usb_ctl_msg() is used directly for memory allocation without validation. This length is controlled by the USB device.

The allocated buffer is cast to a uac3_cluster_header_descriptor and its fields are accessed without verifying that the buffer is large enough. If the device returns a smaller than expected length, this leads to an out-of-bounds read.

Add a length check to ensure the buffer is large enough for uac3_cluster_header_descriptor.