Re: [PATCH net-next v4 3/5] net: hdlc_fr: Improve the initial checks when we receive an skb

[Willem de Bruijn]

On Thu, Oct 29, 2020 at 10:33 PM Xie He <xie.he.0141@xxxxxxxxx> wrote:
>
> 1.
> Change the skb->len check from "<= 4" to "< 4".
> At first we only need to ensure a 4-byte header is present. We indeed
> normally need the 5th byte, too, but it'd be more logical and cleaner
> to check its existence when we actually need it.
>
> 2.
> Add an fh->ea2 check to the initial checks in fr_rx. fh->ea2 == 1 means
> the second address byte is the final address byte. We only support the
> case where the address length is 2 bytes.

Can you elaborate a bit for readers not intimately familiar with the codebase?

Is there something in the following code that has this implicit
assumption on 2-byte address lengths?