diff options
| author | Florian Westphal <fw@strlen.de> | 2023-09-29 10:42:10 +0200 |
|---|---|---|
| committer | Florian Westphal <fw@strlen.de> | 2023-10-04 14:12:01 +0200 |
| commit | af84f9e447a65b4b9f79e7e5d69e19039b431c56 (patch) | |
| tree | be8ad3a2ab4243a2ab132af9c63bd4eddfa749f4 /net | |
| parent | 51e7a66666e0ca9642c59464ef8359f0ac604d41 (diff) | |
netfilter: nft_payload: rebuild vlan header on h_proto access
nft can perform merging of adjacent payload requests.
This means that:
ether saddr 00:11 ... ether type 8021ad ...
is a single payload expression, for 8 bytes, starting at the
ethernet source offset.
Check that offset+length is fully within the source/destination mac
addersses.
This bug prevents 'ether type' from matching the correct h_proto in case
vlan tag got stripped.
Fixes: de6843be3082 ("netfilter: nft_payload: rebuild vlan header when needed")
Reported-by: David Ward <david.ward@ll.mit.edu>
Signed-off-by: Florian Westphal <fw@strlen.de>
Diffstat (limited to 'net')
| -rw-r--r-- | net/netfilter/nft_payload.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c index 8cb800989947..120f6d395b98 100644 --- a/net/netfilter/nft_payload.c +++ b/net/netfilter/nft_payload.c @@ -154,6 +154,17 @@ int nft_payload_inner_offset(const struct nft_pktinfo *pkt) return pkt->inneroff; } +static bool nft_payload_need_vlan_copy(const struct nft_payload *priv) +{ + unsigned int len = priv->offset + priv->len; + + /* data past ether src/dst requested, copy needed */ + if (len > offsetof(struct ethhdr, h_proto)) + return true; + + return false; +} + void nft_payload_eval(const struct nft_expr *expr, struct nft_regs *regs, const struct nft_pktinfo *pkt) @@ -172,7 +183,7 @@ void nft_payload_eval(const struct nft_expr *expr, goto err; if (skb_vlan_tag_present(skb) && - priv->offset >= offsetof(struct ethhdr, h_proto)) { + nft_payload_need_vlan_copy(priv)) { if (!nft_payload_copy_vlan(dest, skb, priv->offset, priv->len)) goto err; |