On Wed, Jul 19, 2023 at 6:10 AM David Laight <David.Laight@xxxxxxxxxx> wrote:
>
> From: Alexei Starovoitov
> > Sent: 19 July 2023 00:40
> >
> > Network drivers always call skb_header_pointer() with non-null buffer.
> > Remove !buffer check to prevent accidental misuse of skb_header_pointer().
> > Introduce skb_pointer_if_linear() instead.
> >
> ...
> > +static inline void * __must_check
> > +skb_pointer_if_linear(const struct sk_buff *skb, int offset, int len)
> > +{
> > + if (likely(skb_headlen(skb) - offset >= len))
> > + return skb->data + offset;
> > + return NULL;
> > +}
>
> Shouldn't both 'offset' and 'len' be 'unsigned int' ?
>
> The check should probably be written:
> offset + len <= skb_headlen(skb)
> so that it fails if 'offset' is also large.
> (Provided 'offset + len' itself doesn't wrap.)
I agree that this style is easier to read, but
consistency with skb_header_pointer() trumps all such considerations.
