[PATCH 1/6] net: improve check for no IP options

[Ramon Fried]

On Fri, Oct 14, 2022 at 8:43 PM Rasmus Villemoes
<rasmus.villemoes at prevas.dk> wrote:
>
> There's no reason we should accept an IP packet with a malformed IHL
> field. So ensure that it is exactly 5, not just <= 5.
>
> Signed-off-by: Rasmus Villemoes <rasmus.villemoes at prevas.dk>
> ---
>  net/net.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/net.c b/net/net.c
> index 81905f6315..536731245b 100644
> --- a/net/net.c
> +++ b/net/net.c
> @@ -1209,7 +1209,7 @@ void net_process_received_packet(uchar *in_packet, int len)
>                 if ((ip->ip_hl_v & 0xf0) != 0x40)
>                         return;
>                 /* Can't deal with IP options (headers != 20 bytes) */
> -               if ((ip->ip_hl_v & 0x0f) > 0x05)
> +               if ((ip->ip_hl_v & 0x0f) != 0x05)
>                         return;
>                 /* Check the Checksum of the header */
>                 if (!ip_checksum_ok((uchar *)ip, IP_HDR_SIZE)) {
> --
> 2.37.2
>
Reviewed-by: Ramon Fried <rfried.dev at gmail.com>