On Mon, Feb 25, 2019 at 07:25:37PM +0800, Xin Long wrote:
> sctp_hdr(skb) only works when skb->transport_header is set properly.
>
> But in the path of nf_conntrack_in: sctp_packet() -> sctp_error()
>
> skb->transport_header is not guaranteed to be right value for sctp.
> It will cause to fail to check the checksum for sctp packets.
>
> So fix it by using offset, which is always right in all places.
>
> Fixes: e6d8b64b34aa ("net: sctp: fix and consolidate SCTP checksumming code")
> Reported-by: Li Shuang <shuali@xxxxxxxxxx>
> Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
> ---
> include/net/sctp/checksum.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/net/sctp/checksum.h b/include/net/sctp/checksum.h
> index 32ee65a..1c6e6c0 100644
> --- a/include/net/sctp/checksum.h
> +++ b/include/net/sctp/checksum.h
> @@ -61,7 +61,7 @@ static inline __wsum sctp_csum_combine(__wsum csum, __wsum csum2,
> static inline __le32 sctp_compute_cksum(const struct sk_buff *skb,
> unsigned int offset)
> {
> - struct sctphdr *sh = sctp_hdr(skb);
> + struct sctphdr *sh = (struct sctphdr *)(skb->data + offset);
> const struct skb_checksum_ops ops = {
> .update = sctp_csum_update,
> .combine = sctp_csum_combine,
> --
> 2.1.0
>
>
Shouldn't you use skb_set_transport_header and skb_transport_header here?
Neil
