Re: [dpdk-dev] [PATCH] net: check that seg is valid before dereference

[wangyunjian <wangyunjian@huawei.com>]

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Chas Williams
> Sent: Monday, September 28, 2020 11:32 PM
> To: dev@dpdk.org
> Cc: olivier.matz@6wind.com; Chas Williams <3chas3@gmail.com>
> Subject: [dpdk-dev] [PATCH] net: check that seg is valid before dereference
> 
> If the overall pkt_len and segment lengths are out of agreement, it is possible
> for the seg to be NULL after the loop. Add assert to check this condition in
> debug builds.
> 
> Fixes: c442fed81bb9 ("net: add function to calculate checksum in mbuf")
> 
> Signed-off-by: Chas Williams <3chas3@gmail.com>
> ---
>  lib/librte_net/rte_ip.h | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/lib/librte_net/rte_ip.h b/lib/librte_net/rte_ip.h index
> fcd1eb342..6b3e4cdda 100644
> --- a/lib/librte_net/rte_ip.h
> +++ b/lib/librte_net/rte_ip.h
> @@ -225,6 +225,7 @@ rte_raw_cksum_mbuf(const struct rte_mbuf *m,
> uint32_t off, uint32_t len,
>  			break;
>  		off -= seglen;
>  	}
> +	RTE_ASSERT(seg != NULL);

Is it better to return an error code?

>  	seglen -= off;
>  	buf = rte_pktmbuf_mtod_offset(seg, const char *, off);
>  	if (seglen >= len) {
> --
> 2.26.2