[PATCH 4.19 139/421] netfilter: nft_tproxy: restrict support to TCP and UDP transport protocols

Greg Kroah-Hartman
2021-07-19T16:12:30Z

From: Pablo Neira Ayuso <pablo@netfilter.org>

[ Upstream commit 52f0f4e178c757b3d356087376aad8bd77271828 ]

Add unfront check for TCP and UDP packets before performing further
processing.

Fixes: 4ed8eb6570a4 ("netfilter: nf_tables: Add native tproxy support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/nft_tproxy.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nft_tproxy.c b/net/netfilter/nft_tproxy.c
index 95980154ef02..b97ab1198b03 100644
--- a/net/netfilter/nft_tproxy.c
+++ b/net/netfilter/nft_tproxy.c
@@ -30,6 +30,12 @@ static void nft_tproxy_eval_v4(const struct nft_expr *expr,
__be16 tport = 0;
struct sock *sk;

+ if (pkt->tprot != IPPROTO_TCP &&
+ pkt->tprot != IPPROTO_UDP) {
+ regs->verdict.code = NFT_BREAK;
+ return;
+ }
+
hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr);
if (!hp) {
regs->verdict.code = NFT_BREAK;
@@ -91,7 +97,8 @@ static void nft_tproxy_eval_v6(const struct nft_expr *expr,

memset(&taddr, 0, sizeof(taddr));

- if (!pkt->tprot_set) {
+ if (pkt->tprot != IPPROTO_TCP &&
+ pkt->tprot != IPPROTO_UDP) {
regs->verdict.code = NFT_BREAK;
return;
}
--
2.30.2