[bsp][nuvoton] Clamp CAN receive DLC

[Zepp-Hanzj]

Description / 描述

The nuvoton classic CAN drivers clamp the received DLC value from the hardware register in nu_can_recvmsg(), preventing out-of-bounds read/write on the fixed-size Data[8] buffer when the hardware reports an abnormal DLC (9~15).

nuvoton 经典 CAN 驱动在 nu_can_recvmsg() 中对来自硬件寄存器的接收 DLC 值做 clamp，防止当硬件报告异常 DLC（9~15）时对固定大小 Data[8] 缓冲区越界读写。

Why / 为什么需要

pmsg->len = tMsg.DLC 直接使用硬件寄存器值，随后 rt_memcpy(pmsg->data, &tMsg.Data[0], pmsg->len) 以该值作为拷贝长度。经典 CAN 的 tMsg.Data 和 pmsg->data 都是 8 字节，若 DLC > 8 会导致越界读（tMsg.Data）和越界写（pmsg->data）。发送侧 nu_can_sendmsg 已用 IS_CAN_DLC(len) <= 8U 校验，接收侧却缺失，不对称。

How / 修改了哪些文件

• bsp/nuvoton/libraries/m2354/rtt_port/drv_can.c: clamp DLC to sizeof(tMsg.Data)
• bsp/nuvoton/libraries/m480/rtt_port/drv_can.c: clamp DLC to sizeof(tMsg.Data)
• bsp/nuvoton/libraries/n9h30/rtt_port/drv_can.c: clamp DLC to sizeof(tMsg.Data)
• bsp/nuvoton/libraries/nuc980/rtt_port/drv_can.c: clamp DLC to sizeof(tMsg.Data)

This fix mirrors the previously merged [bsp][loongson] Clamp CAN receive DLC change.

[github-actions]

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[github-actions]

MemBrowse Memory Report

No memory changes detected for:

• nuvoton-m487