On Mon, Mar 27, 2023 at 12:41:16PM +0300, Igor Artemiev wrote:
> After having been compared to NULL value at nfnetlink_log.c:560,
> pointer 'skb->dev' is dereferenced at nfnetlink_log.c:576.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Signed-off-by: Igor Artemiev <Igor.A.Artemiev@xxxxxxx>
> ---
> net/netfilter/nfnetlink_log.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
> index d97eb280cb2e..2711509eb9a5 100644
> --- a/net/netfilter/nfnetlink_log.c
> +++ b/net/netfilter/nfnetlink_log.c
> @@ -572,7 +572,7 @@ __build_packet_message(struct nfnl_log_net *log,
> }
> }
>
> - if (indev && skb_mac_header_was_set(skb)) {
> + if (indev && skb->dev && skb_mac_header_was_set(skb)) {
This cannot ever happen, we assume skb->dev is always set on.
> if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
> nla_put_be16(inst->skb, NFULA_HWLEN,
> htons(skb->dev->hard_header_len)))
> --
> 2.30.2
>
