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netfilter: nf_tables: don't drop IPv6 packets that cannot parse transport

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This is overly conservative and not flexible at all, so better let them
go through and let the filtering policy decide what to do with them. We
use skb_header_pointer() all over the place so we would just fail to
match when trying to access fields from malformed traffic.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Pablo Neira Ayuso 2016-09-09 12:42:53 +02:00
parent 10151d7b03
commit 71212c9b04
3 changed files with 4 additions and 10 deletions
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6
include/net/netfilter/nf_tables_ipv6.h
View File

@ -4,7 +4,7 @@
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <net/ipv6.h>
static inline int
static inline void
nft_set_pktinfo_ipv6(struct nft_pktinfo *pkt,
struct sk_buff *skb,
const struct nf_hook_state *state)
@ -17,15 +17,13 @@ nft_set_pktinfo_ipv6(struct nft_pktinfo *pkt,
protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, NULL);
if (protohdr < 0) {
nft_set_pktinfo_proto_unspec(pkt, skb);
return -1;
return;
}
pkt->tprot_set = true;
pkt->tprot = protohdr;
pkt->xt.thoff = thoff;
pkt->xt.fragoff = frag_off;
return 0;
}
static inline int

4
net/ipv6/netfilter/nf_tables_ipv6.c
View File

@ -22,9 +22,7 @@ static unsigned int nft_do_chain_ipv6(void *priv,
{
struct nft_pktinfo pkt;
/* malformed packet, drop it */
if (nft_set_pktinfo_ipv6(&pkt, skb, state) < 0)
return NF_DROP;
nft_set_pktinfo_ipv6(&pkt, skb, state);
return nft_do_chain(&pkt, priv);
}

4
net/ipv6/netfilter/nft_chain_route_ipv6.c
View File

@ -32,9 +32,7 @@ static unsigned int nf_route_table_hook(void *priv,
u_int8_t hop_limit;
u32 mark, flowlabel;
/* malformed packet, drop it */
if (nft_set_pktinfo_ipv6(&pkt, skb, state) < 0)
return NF_DROP;
nft_set_pktinfo_ipv6(&pkt, skb, state);
/* save source/dest address, mark, hoplimit, flowlabel, priority */
memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr));