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| author | Florian Westphal <fw@strlen.de> | 2022-01-29 17:13:23 +0100 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2022-02-04 05:38:15 +0100 |
| commit | a9e8503def0fd4ed89ade1f61c315f904581d439 (patch) | |
| tree | 7e7678e27bded2e65072d96af8f9a227f5cca3ab | |
| parent | 77b337196a9d87f3d6bb9b07c0436ecafbffda1e (diff) | |
| download | linux-stable-a9e8503def0fd4ed89ade1f61c315f904581d439.tar.gz linux-stable-a9e8503def0fd4ed89ade1f61c315f904581d439.tar.bz2 linux-stable-a9e8503def0fd4ed89ade1f61c315f904581d439.zip | |
netfilter: nft_payload: don't allow th access for fragments
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@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
| -rw-r--r-- | net/netfilter/nft_exthdr.c | 2 | ||||
| -rw-r--r-- | 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; } |