diff options
author | Pablo Neira Ayuso <pablo@netfilter.org> | 2019-05-29 13:25:38 +0200 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2019-05-30 14:18:18 -0700 |
commit | 764dd163ac922f8683b5bcd3007251ce7b26cd33 (patch) | |
tree | dc8afac25b5d7de268b3877da0da9d0e70f44003 /net | |
parent | 3c171f496ef57774f8e5d509923372549734877f (diff) |
netfilter: nf_conntrack_bridge: add support for IPv6
br_defrag() and br_fragment() indirections are added in case that IPv6
support comes as a module, to avoid pulling innecessary dependencies in.
The new fraglist iterator and fragment transformer APIs are used to
implement the refragmentation code.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r-- | net/bridge/netfilter/nf_conntrack_bridge.c | 59 | ||||
-rw-r--r-- | net/ipv6/netfilter.c | 123 |
2 files changed, 180 insertions, 2 deletions
diff --git a/net/bridge/netfilter/nf_conntrack_bridge.c b/net/bridge/netfilter/nf_conntrack_bridge.c index 2571528ed582..b675cd7c1a82 100644 --- a/net/bridge/netfilter/nf_conntrack_bridge.c +++ b/net/bridge/netfilter/nf_conntrack_bridge.c @@ -163,6 +163,31 @@ static unsigned int nf_ct_br_defrag4(struct sk_buff *skb, return NF_STOLEN; } +static unsigned int nf_ct_br_defrag6(struct sk_buff *skb, + const struct nf_hook_state *state) +{ + u16 zone_id = NF_CT_DEFAULT_ZONE_ID; + enum ip_conntrack_info ctinfo; + struct br_input_skb_cb cb; + const struct nf_conn *ct; + int err; + + ct = nf_ct_get(skb, &ctinfo); + if (ct) + zone_id = nf_ct_zone_id(nf_ct_zone(ct), CTINFO2DIR(ctinfo)); + + br_skb_cb_save(skb, &cb, sizeof(struct inet6_skb_parm)); + + err = nf_ipv6_br_defrag(state->net, skb, + IP_DEFRAG_CONNTRACK_BRIDGE_IN + zone_id); + /* queued */ + if (err == -EINPROGRESS) + return NF_STOLEN; + + br_skb_cb_restore(skb, &cb, IP6CB(skb)->frag_max_size); + return err == 0 ? NF_ACCEPT : NF_DROP; +} + static int nf_ct_br_ip_check(const struct sk_buff *skb) { const struct iphdr *iph; @@ -177,6 +202,23 @@ static int nf_ct_br_ip_check(const struct sk_buff *skb) len = ntohs(iph->tot_len); if (skb->len < nhoff + len || len < (iph->ihl * 4)) + return -1; + + return 0; +} + +static int nf_ct_br_ipv6_check(const struct sk_buff *skb) +{ + const struct ipv6hdr *hdr; + int nhoff, len; + + nhoff = skb_network_offset(skb); + hdr = ipv6_hdr(skb); + if (hdr->version != 6) + return -1; + + len = ntohs(hdr->payload_len) + sizeof(struct ipv6hdr) + nhoff; + if (skb->len < len) return -1; return 0; @@ -212,7 +254,19 @@ static unsigned int nf_ct_bridge_pre(void *priv, struct sk_buff *skb, ret = nf_ct_br_defrag4(skb, &bridge_state); break; case htons(ETH_P_IPV6): - /* fall through */ + if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) + return NF_ACCEPT; + + len = sizeof(struct ipv6hdr) + ntohs(ipv6_hdr(skb)->payload_len); + if (pskb_trim_rcsum(skb, len)) + return NF_ACCEPT; + + if (nf_ct_br_ipv6_check(skb)) + return NF_ACCEPT; + + bridge_state.pf = NFPROTO_IPV6; + ret = nf_ct_br_defrag6(skb, &bridge_state); + break; default: nf_ct_set(skb, NULL, IP_CT_UNTRACKED); return NF_ACCEPT; @@ -254,7 +308,8 @@ nf_ct_bridge_refrag(struct sk_buff *skb, const struct nf_hook_state *state, nf_br_ip_fragment(state->net, state->sk, skb, &data, output); break; case htons(ETH_P_IPV6): - return NF_ACCEPT; + nf_br_ip6_fragment(state->net, state->sk, skb, &data, output); + break; default: WARN_ON_ONCE(1); return NF_DROP; diff --git a/net/ipv6/netfilter.c b/net/ipv6/netfilter.c index 1240ccd57f39..c6665382acb5 100644 --- a/net/ipv6/netfilter.c +++ b/net/ipv6/netfilter.c @@ -16,6 +16,9 @@ #include <net/ip6_route.h> #include <net/xfrm.h> #include <net/netfilter/nf_queue.h> +#include <net/netfilter/nf_conntrack_bridge.h> +#include <net/netfilter/ipv6/nf_defrag_ipv6.h> +#include "../bridge/br_private.h" int ip6_route_me_harder(struct net *net, struct sk_buff *skb) { @@ -109,6 +112,122 @@ int __nf_ip6_route(struct net *net, struct dst_entry **dst, } EXPORT_SYMBOL_GPL(__nf_ip6_route); +int br_ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, + struct nf_ct_bridge_frag_data *data, + int (*output)(struct net *, struct sock *sk, + const struct nf_ct_bridge_frag_data *data, + struct sk_buff *)) +{ + int frag_max_size = BR_INPUT_SKB_CB(skb)->frag_max_size; + struct ip6_frag_state state; + u8 *prevhdr, nexthdr = 0; + unsigned int mtu, hlen; + int hroom, err = 0; + __be32 frag_id; + + err = ip6_find_1stfragopt(skb, &prevhdr); + if (err < 0) + goto blackhole; + hlen = err; + nexthdr = *prevhdr; + + mtu = skb->dev->mtu; + if (frag_max_size > mtu || + frag_max_size < IPV6_MIN_MTU) + goto blackhole; + + mtu = frag_max_size; + if (mtu < hlen + sizeof(struct frag_hdr) + 8) + goto blackhole; + mtu -= hlen + sizeof(struct frag_hdr); + + frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr, + &ipv6_hdr(skb)->saddr); + + if (skb->ip_summed == CHECKSUM_PARTIAL && + (err = skb_checksum_help(skb))) + goto blackhole; + + hroom = LL_RESERVED_SPACE(skb->dev); + if (skb_has_frag_list(skb)) { + unsigned int first_len = skb_pagelen(skb); + struct ip6_fraglist_iter iter; + struct sk_buff *frag2; + + if (first_len - hlen > mtu || + skb_headroom(skb) < (hroom + sizeof(struct frag_hdr))) + goto blackhole; + + if (skb_cloned(skb)) + goto slow_path; + + skb_walk_frags(skb, frag2) { + if (frag2->len > mtu || + skb_headroom(frag2) < (hlen + hroom + sizeof(struct frag_hdr))) + goto blackhole; + + /* Partially cloned skb? */ + if (skb_shared(frag2)) + goto slow_path; + } + + err = ip6_fraglist_init(skb, hlen, prevhdr, nexthdr, frag_id, + &iter); + if (err < 0) + goto blackhole; + + for (;;) { + /* Prepare header of the next frame, + * before previous one went down. + */ + if (iter.frag) + ip6_fraglist_prepare(skb, &iter); + + err = output(net, sk, data, skb); + if (err || !iter.frag) + break; + + skb = ip6_fraglist_next(&iter); + } + + kfree(iter.tmp_hdr); + if (!err) + return 0; + + kfree_skb_list(iter.frag_list); + return err; + } +slow_path: + /* This is a linearized skbuff, the original geometry is lost for us. + * This may also be a clone skbuff, we could preserve the geometry for + * the copies but probably not worth the effort. + */ + ip6_frag_init(skb, hlen, mtu, skb->dev->needed_tailroom, + LL_RESERVED_SPACE(skb->dev), prevhdr, nexthdr, frag_id, + &state); + + while (state.left > 0) { + struct sk_buff *skb2; + + skb2 = ip6_frag_next(skb, &state); + if (IS_ERR(skb2)) { + err = PTR_ERR(skb2); + goto blackhole; + } + + err = output(net, sk, data, skb2); + if (err) + goto blackhole; + } + consume_skb(skb); + return err; + +blackhole: + kfree_skb(skb); + return 0; +} +EXPORT_SYMBOL_GPL(br_ip6_fragment); + static const struct nf_ipv6_ops ipv6ops = { #if IS_MODULE(CONFIG_IPV6) .chk_addr = ipv6_chk_addr, @@ -119,6 +238,10 @@ static const struct nf_ipv6_ops ipv6ops = { .route_input = ip6_route_input, .fragment = ip6_fragment, .reroute = nf_ip6_reroute, +#if IS_MODULE(CONFIG_NF_CONNTRACK_BRIDGE) + .br_defrag = nf_ct_frag6_gather, + .br_fragment = br_ip6_fragment, +#endif }; int __init ipv6_netfilter_init(void) |