Re: [PATCH net] nfp: bpf: prevent integer overflow in nfp_bpf_event_output()

Dan Carpenter
2025-01-14T10:45:09Z

[ I tried to send this email yesterday but apparently gmail blocked
it for security reasons? So weird. - dan ]

On Mon, Jan 13, 2025 at 01:32:11PM +0100, Alexander Lobakin wrote:
> From: Dan Carpenter <dan.carpenter@linaro.org>
> Date: Mon, 13 Jan 2025 09:18:39 +0300
>
> > The "sizeof(struct cmsg_bpf_event) + pkt_size + data_size" math could
> > potentially have an integer wrapping bug on 32bit systems. Check for
>
> Not in practice I suppose? Do we need to fix "never" bugs?
>

No, this is from static analysis. We don't need to fix never bugs.

This is called from nfp_bpf_ctrl_msg_rx() and nfp_bpf_ctrl_msg_rx_raw()
and I assumed that since pkt_size and data_size come from skb->data on
the rx path then they couldn't be trusted.

Where is the bounds checking?

regards,
dan carpenter