Re: [PATCH nf] netfilter: nft_osf: restrict it to ipv6

Fernando Fernandez Mancera
2026-04-14T11:53:17Z

On 4/14/26 1:08 PM, Pablo Neira Ayuso wrote:
> This expression only supports for ipv4, restrict it.
>
> Fixes: b96af92d6eaf ("netfilter: nf_tables: implement Passive OS fingerprint module in nft_osf")
> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
> ---
> net/netfilter/nft_osf.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/net/netfilter/nft_osf.c b/net/netfilter/nft_osf.c
> index 1c0b493ef0a9..bdc2f6c90e2f 100644
> --- a/net/netfilter/nft_osf.c
> +++ b/net/netfilter/nft_osf.c
> @@ -28,6 +28,11 @@ static void nft_osf_eval(const struct nft_expr *expr, struct nft_regs *regs,
> struct nf_osf_data data;
> struct tcphdr _tcph;
>
> + if (nft_pf(pkt) != NFPROTO_IPV4) {
> + regs->verdict.code = NFT_BREAK;
> + return;
> + }
> +
> if (pkt->tprot != IPPROTO_TCP) {
> regs->verdict.code = NFT_BREAK;
> return;
> @@ -114,7 +119,6 @@ static int nft_osf_validate(const struct nft_ctx *ctx,
>
> switch (ctx->family) {
> case NFPROTO_IPV4:
> - case NFPROTO_IPV6:
> case NFPROTO_INET:
> hooks = (1 << NF_INET_LOCAL_IN) |
> (1 << NF_INET_PRE_ROUTING) |

Reviewed-by: Fernando Fernandez Mancera <fmancera@suse.de>

I have the feeling I should re-review everything I did 7 years ago :-)

Thanks!