From: Florian Westphal <fw@xxxxxxxxx>
Loads relative to ->thoff naturally expect that this points to the
transport header, but this is only true if pkt->fragoff == 0.
This has little effect for rulesets with connection tracking/nat because
these enable ip defra. For other rulesets this prevents false matches.
Fixes: 96518518cc41 ("netfilter: add nftables")
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/netfilter/nft_exthdr.c | 2 +-
net/netfilter/nft_payload.c | 9 +++++----
2 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c
index dbe1f2e7dd9e..9e927ab4df15 100644
--- a/net/netfilter/nft_exthdr.c
+++ b/net/netfilter/nft_exthdr.c
@@ -167,7 +167,7 @@ nft_tcp_header_pointer(const struct nft_pktinfo *pkt,
{
struct tcphdr *tcph;
- if (pkt->tprot != IPPROTO_TCP)
+ if (pkt->tprot != IPPROTO_TCP || pkt->fragoff)
return NULL;
tcph = skb_header_pointer(pkt->skb, nft_thoff(pkt), sizeof(*tcph), buffer);
diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c
index 940fed9a760b..5cc06aef4345 100644
--- a/net/netfilter/nft_payload.c
+++ b/net/netfilter/nft_payload.c
@@ -83,7 +83,7 @@ static int __nft_payload_inner_offset(struct nft_pktinfo *pkt)
{
unsigned int thoff = nft_thoff(pkt);
- if (!(pkt->flags & NFT_PKTINFO_L4PROTO))
+ if (!(pkt->flags & NFT_PKTINFO_L4PROTO) || pkt->fragoff)
return -1;
switch (pkt->tprot) {
@@ -147,7 +147,7 @@ void nft_payload_eval(const struct nft_expr *expr,
offset = skb_network_offset(skb);
break;
case NFT_PAYLOAD_TRANSPORT_HEADER:
- if (!(pkt->flags & NFT_PKTINFO_L4PROTO))
+ if (!(pkt->flags & NFT_PKTINFO_L4PROTO) || pkt->fragoff)
goto err;
offset = nft_thoff(pkt);
break;
@@ -688,7 +688,7 @@ static void nft_payload_set_eval(const struct nft_expr *expr,
offset = skb_network_offset(skb);
break;
case NFT_PAYLOAD_TRANSPORT_HEADER:
- if (!(pkt->flags & NFT_PKTINFO_L4PROTO))
+ if (!(pkt->flags & NFT_PKTINFO_L4PROTO) || pkt->fragoff)
goto err;
offset = nft_thoff(pkt);
break;
@@ -728,7 +728,8 @@ static void nft_payload_set_eval(const struct nft_expr *expr,
if (priv->csum_type == NFT_PAYLOAD_CSUM_SCTP &&
pkt->tprot == IPPROTO_SCTP &&
skb->ip_summed != CHECKSUM_PARTIAL) {
- if (nft_payload_csum_sctp(skb, nft_thoff(pkt)))
+ if (pkt->fragoff == 0 &&
+ nft_payload_csum_sctp(skb, nft_thoff(pkt)))
goto err;
}
--
2.30.2
