wifi: rtw88: fix OOB read from firmware RX descriptor exceeding DMA buffer

wifi: rtw88: fix OOB read from firmware RX descriptor exceeding DMA buffer

In rtw_pci_rx_napi(), new_len is computed as the sum of pkt_len (14-bit
descriptor field, max 16383) and pkt_offset (drv_info_sz + shift, both
firmware-controlled). The result can exceed RTK_PCI_RX_BUF_SIZE (11478),
causing an out-of-bounds read from the pre-allocated DMA buffer when
skb_put_data copies new_len bytes. The USB transport already validates
this (rtw_usb_rx_data_put checks against RTW_USB_MAX_RECVBUF_SZ); the
PCIe path does not.

Add a check that new_len does not exceed the DMA buffer size.

Fixes: e3037485c68e ("rtw88: new Realtek 802.11ac driver")
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20260421111434.3389674-1-tristmd@gmail.com