[PATCH 6.9 285/374] netfilter: nft_payload: restore vlan q-in-q match support

Greg Kroah-Hartman
2024-06-06T14:10:47Z

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

[ Upstream commit aff5c01fa1284d606f8e7cbdaafeef2511bb46c1 ]

Revert f6ae9f120dad ("netfilter: nft_payload: add C-VLAN support").

f41f72d09ee1 ("netfilter: nft_payload: simplify vlan header handling")
already allows to match on inner vlan tags by subtract the vlan header
size to the payload offset which has been popped and stored in skbuff
metadata fields.

Fixes: f6ae9f120dad ("netfilter: nft_payload: add C-VLAN support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/nft_payload.c | 23 +++++++----------------
1 file changed, 7 insertions(+), 16 deletions(-)

diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c
index 0a689c8e0295d..a3cb5dbcb362c 100644
--- a/net/netfilter/nft_payload.c
+++ b/net/netfilter/nft_payload.c
@@ -45,36 +45,27 @@ nft_payload_copy_vlan(u32 *d, const struct sk_buff *skb, u8 offset, u8 len)
int mac_off = skb_mac_header(skb) - skb->data;
u8 *vlanh, *dst_u8 = (u8 *) d;
struct vlan_ethhdr veth;
- u8 vlan_hlen = 0;
-
- if ((skb->protocol == htons(ETH_P_8021AD) ||
- skb->protocol == htons(ETH_P_8021Q)) &&
- offset >= VLAN_ETH_HLEN && offset < VLAN_ETH_HLEN + VLAN_HLEN)
- vlan_hlen += VLAN_HLEN;

vlanh = (u8 *) &veth;
- if (offset < VLAN_ETH_HLEN + vlan_hlen) {
+ if (offset < VLAN_ETH_HLEN) {
u8 ethlen = len;

- if (vlan_hlen &&
- skb_copy_bits(skb, mac_off, &veth, VLAN_ETH_HLEN) < 0)
- return false;
- else if (!nft_payload_rebuild_vlan_hdr(skb, mac_off, &veth))
+ if (!nft_payload_rebuild_vlan_hdr(skb, mac_off, &veth))
return false;

- if (offset + len > VLAN_ETH_HLEN + vlan_hlen)
- ethlen -= offset + len - VLAN_ETH_HLEN - vlan_hlen;
+ if (offset + len > VLAN_ETH_HLEN)
+ ethlen -= offset + len - VLAN_ETH_HLEN;

- memcpy(dst_u8, vlanh + offset - vlan_hlen, ethlen);
+ memcpy(dst_u8, vlanh + offset, ethlen);

len -= ethlen;
if (len == 0)
return true;

dst_u8 += ethlen;
- offset = ETH_HLEN + vlan_hlen;
+ offset = ETH_HLEN;
} else {
- offset -= VLAN_HLEN + vlan_hlen;
+ offset -= VLAN_HLEN;
}

return skb_copy_bits(skb, offset + mac_off, dst_u8, len) == 0;
--
2.43.0