[PATCH 3/3] net: emaclite: fix handling for IP packets with specific lengths

[Ramon Fried]

On Wed, Jul 13, 2022 at 5:02 PM Samuel Obuch <samuel.obuch at codasip.com> wrote:
>
> The maximum length is capped similarly to the emaclite_send function.
> Avoid integer underflow for values of ip->ip_len < 30, the minimum
> length of an IP packet is 21 bytes.
>
> Signed-off-by: Samuel Obuch <samuel.obuch at codasip.com>
> ---
>  drivers/net/xilinx_emaclite.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/xilinx_emaclite.c b/drivers/net/xilinx_emaclite.c
> index de7a2dee0b..21c450ec46 100644
> --- a/drivers/net/xilinx_emaclite.c
> +++ b/drivers/net/xilinx_emaclite.c
> @@ -518,6 +518,8 @@ try_again:
>                 length = ntohs(ip->ip_len);
>                 length += ETHER_HDR_SIZE + ETH_FCS_LEN;
>                 debug("IP Packet %x\n", length);
> +               if (length > PKTSIZE)
> +                       length = PKTSIZE;
>                 break;
>         default:
>                 debug("Other Packet\n");
> @@ -526,7 +528,7 @@ try_again:
>         }
>
>         /* Read the rest of the packet which is longer then first read */
> -       if (length != first_read)
> +       if (length > first_read)
>                 xemaclite_alignedread(addr + first_read,
>                                       etherrxbuff + first_read,
>                                       length - first_read);
> --
> 2.31.1
>
+ Michal