From f6ae9f120dada00abfb47313364c35118469455f Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Mon, 4 Nov 2019 14:41:34 +0100 Subject: [PATCH] netfilter: nft_payload: add C-VLAN support If the encapsulated ethertype announces another inner VLAN header and the offset falls within the boundaries of the inner VLAN header, then adjust arithmetics to include the extra VLAN header length and fetch the bytes from the vlan header in the skbuff data area that represents this inner VLAN header. Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nft_payload.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c index 3db9c802ea62..0877d46b8605 100644 --- a/net/netfilter/nft_payload.c +++ b/net/netfilter/nft_payload.c @@ -43,27 +43,36 @@ 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) { + if (offset < VLAN_ETH_HLEN + vlan_hlen) { u8 ethlen = len; - if (!nft_payload_rebuild_vlan_hdr(skb, mac_off, &veth)) + 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)) return false; - if (offset + len > VLAN_ETH_HLEN) - ethlen -= offset + len - VLAN_ETH_HLEN; + if (offset + len > VLAN_ETH_HLEN + vlan_hlen) + ethlen -= offset + len - VLAN_ETH_HLEN + vlan_hlen; - memcpy(dst_u8, vlanh + offset, ethlen); + memcpy(dst_u8, vlanh + offset - vlan_hlen, ethlen); len -= ethlen; if (len == 0) return true; dst_u8 += ethlen; - offset = ETH_HLEN; + offset = ETH_HLEN + vlan_hlen; } else { - offset -= VLAN_HLEN; + offset -= VLAN_HLEN + vlan_hlen; } return skb_copy_bits(skb, offset + mac_off, dst_u8, len) == 0;