net: usb: lan78xx: Fix double free issue with interrupt buffer allocation

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: net: usb: lan78xx: Fix double free issue with interrupt buffer allocation In lan78xx_probe(), the buffer `buf` was being freed twice: once implicitly through `usb_free_urb(dev->urb_intr)` with the `URB_FREE_BUFFER` flag and again explicitly by `kfree(buf)`. This caused a double free issue. To resolve this, reordered `kmalloc()` and `usb_alloc_urb()` calls to simplify the initialization sequence and removed the redundant `kfree(buf)`. Now, `buf` is allocated after `usb_alloc_urb()`, ensuring it is correctly managed by `usb_fill_int_urb()` and freed by `usb_free_urb()` as intended.

References

• https://git.kernel.org/stable/c/cc5aa8e3ad69dcedeba79e667d4a2efb72a305af
• https://git.kernel.org/stable/c/2970ef2fce90c661952ec2b451b0276d5f8d6180
• https://git.kernel.org/stable/c/977128343fc2a30737399b58df8ea77e94f164bd
• https://git.kernel.org/stable/c/a422ebec863d99d5607fb41bb7af3347fcb436d3
• https://git.kernel.org/stable/c/b09512aea6223eec756f52aa584fc29eeab57480
• https://git.kernel.org/stable/c/7ac9f3c981eeceee2ec4d30d850f4a6f50a1ec40
• https://git.kernel.org/stable/c/03819abbeb11117dcbba40bfe322b88c0c88a6b6