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

[Pablo Neira Ayuso <pablo@netfilter.org>]

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) |
-- 
2.47.3