From 6aafeef03b9d9ecf255f3a80ed85ee070260e1ae Mon Sep 17 00:00:00 2001 From: Jiri Pirko Date: Wed, 6 Nov 2013 17:52:20 +0100 Subject: [PATCH] netfilter: push reasm skb through instead of original frag skbs Pushing original fragments through causes several problems. For example for matching, frags may not be matched correctly. Take following example: On HOSTA do: ip6tables -I INPUT -p icmpv6 -j DROP ip6tables -I INPUT -p icmpv6 -m icmp6 --icmpv6-type 128 -j ACCEPT and on HOSTB you do: ping6 HOSTA -s2000 (MTU is 1500) Incoming echo requests will be filtered out on HOSTA. This issue does not occur with smaller packets than MTU (where fragmentation does not happen) As was discussed previously, the only correct solution seems to be to use reassembled skb instead of separete frags. Doing this has positive side effects in reducing sk_buff by one pointer (nfct_reasm) and also the reams dances in ipvs and conntrack can be removed. Future plan is to remove net/ipv6/netfilter/nf_conntrack_reasm.c entirely and use code in net/ipv6/reassembly.c instead. Signed-off-by: Jiri Pirko Acked-by: Julian Anastasov Signed-off-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller --- include/linux/skbuff.h | 32 --------------- include/net/ip_vs.h | 32 +-------------- include/net/netfilter/ipv6/nf_defrag_ipv6.h | 4 +- net/core/skbuff.c | 3 -- net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c | 56 +------------------------- net/ipv6/netfilter/nf_conntrack_reasm.c | 19 +-------- net/ipv6/netfilter/nf_defrag_ipv6_hooks.c | 7 +++- net/netfilter/ipvs/ip_vs_core.c | 55 +------------------------ net/netfilter/ipvs/ip_vs_pe_sip.c | 8 +--- 9 files changed, 13 insertions(+), 203 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 036ec7d..215b5ea 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -337,11 +337,6 @@ typedef unsigned int sk_buff_data_t; typedef unsigned char *sk_buff_data_t; #endif -#if defined(CONFIG_NF_DEFRAG_IPV4) || defined(CONFIG_NF_DEFRAG_IPV4_MODULE) || \ - defined(CONFIG_NF_DEFRAG_IPV6) || defined(CONFIG_NF_DEFRAG_IPV6_MODULE) -#define NET_SKBUFF_NF_DEFRAG_NEEDED 1 -#endif - /** * struct sk_buff - socket buffer * @next: Next buffer in list @@ -374,7 +369,6 @@ typedef unsigned char *sk_buff_data_t; * @protocol: Packet protocol from driver * @destructor: Destruct function * @nfct: Associated connection, if any - * @nfct_reasm: netfilter conntrack re-assembly pointer * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c * @skb_iif: ifindex of device we arrived on * @tc_index: Traffic control index @@ -463,9 +457,6 @@ struct sk_buff { #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) struct nf_conntrack *nfct; #endif -#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED - struct sk_buff *nfct_reasm; -#endif #ifdef CONFIG_BRIDGE_NETFILTER struct nf_bridge_info *nf_bridge; #endif @@ -2595,18 +2586,6 @@ static inline void nf_conntrack_get(struct nf_conntrack *nfct) atomic_inc(&nfct->use); } #endif -#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED -static inline void nf_conntrack_get_reasm(struct sk_buff *skb) -{ - if (skb) - atomic_inc(&skb->users); -} -static inline void nf_conntrack_put_reasm(struct sk_buff *skb) -{ - if (skb) - kfree_skb(skb); -} -#endif #ifdef CONFIG_BRIDGE_NETFILTER static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge) { @@ -2625,10 +2604,6 @@ static inline void nf_reset(struct sk_buff *skb) nf_conntrack_put(skb->nfct); skb->nfct = NULL; #endif -#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED - nf_conntrack_put_reasm(skb->nfct_reasm); - skb->nfct_reasm = NULL; -#endif #ifdef CONFIG_BRIDGE_NETFILTER nf_bridge_put(skb->nf_bridge); skb->nf_bridge = NULL; @@ -2650,10 +2625,6 @@ static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src) nf_conntrack_get(src->nfct); dst->nfctinfo = src->nfctinfo; #endif -#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED - dst->nfct_reasm = src->nfct_reasm; - nf_conntrack_get_reasm(src->nfct_reasm); -#endif #ifdef CONFIG_BRIDGE_NETFILTER dst->nf_bridge = src->nf_bridge; nf_bridge_get(src->nf_bridge); @@ -2665,9 +2636,6 @@ static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src) #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) nf_conntrack_put(dst->nfct); #endif -#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED - nf_conntrack_put_reasm(dst->nfct_reasm); -#endif #ifdef CONFIG_BRIDGE_NETFILTER nf_bridge_put(dst->nf_bridge); #endif diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h index cd7275f..5679d92 100644 --- a/include/net/ip_vs.h +++ b/include/net/ip_vs.h @@ -109,7 +109,6 @@ extern int ip_vs_conn_tab_size; struct ip_vs_iphdr { __u32 len; /* IPv4 simply where L4 starts IPv6 where L4 Transport Header starts */ - __u32 thoff_reasm; /* Transport Header Offset in nfct_reasm skb */ __u16 fragoffs; /* IPv6 fragment offset, 0 if first frag (or not frag)*/ __s16 protocol; __s32 flags; @@ -117,34 +116,12 @@ struct ip_vs_iphdr { union nf_inet_addr daddr; }; -/* Dependency to module: nf_defrag_ipv6 */ -#if defined(CONFIG_NF_DEFRAG_IPV6) || defined(CONFIG_NF_DEFRAG_IPV6_MODULE) -static inline struct sk_buff *skb_nfct_reasm(const struct sk_buff *skb) -{ - return skb->nfct_reasm; -} -static inline void *frag_safe_skb_hp(const struct sk_buff *skb, int offset, - int len, void *buffer, - const struct ip_vs_iphdr *ipvsh) -{ - if (unlikely(ipvsh->fragoffs && skb_nfct_reasm(skb))) - return skb_header_pointer(skb_nfct_reasm(skb), - ipvsh->thoff_reasm, len, buffer); - - return skb_header_pointer(skb, offset, len, buffer); -} -#else -static inline struct sk_buff *skb_nfct_reasm(const struct sk_buff *skb) -{ - return NULL; -} static inline void *frag_safe_skb_hp(const struct sk_buff *skb, int offset, int len, void *buffer, const struct ip_vs_iphdr *ipvsh) { return skb_header_pointer(skb, offset, len, buffer); } -#endif static inline void ip_vs_fill_ip4hdr(const void *nh, struct ip_vs_iphdr *iphdr) @@ -171,19 +148,12 @@ ip_vs_fill_iph_skb(int af, const struct sk_buff *skb, struct ip_vs_iphdr *iphdr) (struct ipv6hdr *)skb_network_header(skb); iphdr->saddr.in6 = iph->saddr; iphdr->daddr.in6 = iph->daddr; - /* ipv6_find_hdr() updates len, flags, thoff_reasm */ - iphdr->thoff_reasm = 0; + /* ipv6_find_hdr() updates len, flags */ iphdr->len = 0; iphdr->flags = 0; iphdr->protocol = ipv6_find_hdr(skb, &iphdr->len, -1, &iphdr->fragoffs, &iphdr->flags); - /* get proto from re-assembled packet and it's offset */ - if (skb_nfct_reasm(skb)) - iphdr->protocol = ipv6_find_hdr(skb_nfct_reasm(skb), - &iphdr->thoff_reasm, - -1, NULL, NULL); - } else #endif { diff --git a/include/net/netfilter/ipv6/nf_defrag_ipv6.h b/include/net/netfilter/ipv6/nf_defrag_ipv6.h index 5613412..27666d8 100644 --- a/include/net/netfilter/ipv6/nf_defrag_ipv6.h +++ b/include/net/netfilter/ipv6/nf_defrag_ipv6.h @@ -6,9 +6,7 @@ void nf_defrag_ipv6_enable(void); int nf_ct_frag6_init(void); void nf_ct_frag6_cleanup(void); struct sk_buff *nf_ct_frag6_gather(struct sk_buff *skb, u32 user); -void nf_ct_frag6_output(unsigned int hooknum, struct sk_buff *skb, - struct net_device *in, struct net_device *out, - int (*okfn)(struct sk_buff *)); +void nf_ct_frag6_consume_orig(struct sk_buff *skb); struct inet_frags_ctl; diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 8c5197f..8cec1e6 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -592,9 +592,6 @@ static void skb_release_head_state(struct sk_buff *skb) #if IS_ENABLED(CONFIG_NF_CONNTRACK) nf_conntrack_put(skb->nfct); #endif -#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED - nf_conntrack_put_reasm(skb->nfct_reasm); -#endif #ifdef CONFIG_BRIDGE_NETFILTER nf_bridge_put(skb->nf_bridge); #endif diff --git a/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c b/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c index 486545e..4cbc6b2 100644 --- a/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c +++ b/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c @@ -169,64 +169,13 @@ out: return nf_conntrack_confirm(skb); } -static unsigned int __ipv6_conntrack_in(struct net *net, - unsigned int hooknum, - struct sk_buff *skb, - const struct net_device *in, - const struct net_device *out, - int (*okfn)(struct sk_buff *)) -{ - struct sk_buff *reasm = skb->nfct_reasm; - const struct nf_conn_help *help; - struct nf_conn *ct; - enum ip_conntrack_info ctinfo; - - /* This packet is fragmented and has reassembled packet. */ - if (reasm) { - /* Reassembled packet isn't parsed yet ? */ - if (!reasm->nfct) { - unsigned int ret; - - ret = nf_conntrack_in(net, PF_INET6, hooknum, reasm); - if (ret != NF_ACCEPT) - return ret; - } - - /* Conntrack helpers need the entire reassembled packet in the - * POST_ROUTING hook. In case of unconfirmed connections NAT - * might reassign a helper, so the entire packet is also - * required. - */ - ct = nf_ct_get(reasm, &ctinfo); - if (ct != NULL && !nf_ct_is_untracked(ct)) { - help = nfct_help(ct); - if ((help && help->helper) || !nf_ct_is_confirmed(ct)) { - nf_conntrack_get_reasm(reasm); - NF_HOOK_THRESH(NFPROTO_IPV6, hooknum, reasm, - (struct net_device *)in, - (struct net_device *)out, - okfn, NF_IP6_PRI_CONNTRACK + 1); - return NF_DROP_ERR(-ECANCELED); - } - } - - nf_conntrack_get(reasm->nfct); - skb->nfct = reasm->nfct; - skb->nfctinfo = reasm->nfctinfo; - return NF_ACCEPT; - } - - return nf_conntrack_in(net, PF_INET6, hooknum, skb); -} - static unsigned int ipv6_conntrack_in(const struct nf_hook_ops *ops, struct sk_buff *skb, const struct net_device *in, const struct net_device *out, int (*okfn)(struct sk_buff *)) { - return __ipv6_conntrack_in(dev_net(in), ops->hooknum, skb, in, out, - okfn); + return nf_conntrack_in(dev_net(in), PF_INET6, ops->hooknum, skb); } static unsigned int ipv6_conntrack_local(const struct nf_hook_ops *ops, @@ -240,8 +189,7 @@ static unsigned int ipv6_conntrack_local(const struct nf_hook_ops *ops, net_notice_ratelimited("ipv6_conntrack_local: packet too short\n"); return NF_ACCEPT; } - return __ipv6_conntrack_in(dev_net(out), ops->hooknum, skb, in, out, - okfn); + return nf_conntrack_in(dev_net(out), PF_INET6, ops->hooknum, skb); } static struct nf_hook_ops ipv6_conntrack_ops[] __read_mostly = { diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c index 4a25826..767ab8d 100644 --- a/net/ipv6/netfilter/nf_conntrack_reasm.c +++ b/net/ipv6/netfilter/nf_conntrack_reasm.c @@ -633,31 +633,16 @@ ret_orig: return skb; } -void nf_ct_frag6_output(unsigned int hooknum, struct sk_buff *skb, - struct net_device *in, struct net_device *out, - int (*okfn)(struct sk_buff *)) +void nf_ct_frag6_consume_orig(struct sk_buff *skb) { struct sk_buff *s, *s2; - unsigned int ret = 0; for (s = NFCT_FRAG6_CB(skb)->orig; s;) { - nf_conntrack_put_reasm(s->nfct_reasm); - nf_conntrack_get_reasm(skb); - s->nfct_reasm = skb; - s2 = s->next; s->next = NULL; - - if (ret != -ECANCELED) - ret = NF_HOOK_THRESH(NFPROTO_IPV6, hooknum, s, - in, out, okfn, - NF_IP6_PRI_CONNTRACK_DEFRAG + 1); - else - kfree_skb(s); - + consume_skb(s); s = s2; } - nf_conntrack_put_reasm(skb); } static int nf_ct_net_init(struct net *net) diff --git a/net/ipv6/netfilter/nf_defrag_ipv6_hooks.c b/net/ipv6/netfilter/nf_defrag_ipv6_hooks.c index ec483aa..7b9a748 100644 --- a/net/ipv6/netfilter/nf_defrag_ipv6_hooks.c +++ b/net/ipv6/netfilter/nf_defrag_ipv6_hooks.c @@ -75,8 +75,11 @@ static unsigned int ipv6_defrag(const struct nf_hook_ops *ops, if (reasm == skb) return NF_ACCEPT; - nf_ct_frag6_output(ops->hooknum, reasm, (struct net_device *)in, - (struct net_device *)out, okfn); + nf_ct_frag6_consume_orig(reasm); + + NF_HOOK_THRESH(NFPROTO_IPV6, ops->hooknum, reasm, + (struct net_device *) in, (struct net_device *) out, + okfn, NF_IP6_PRI_CONNTRACK_DEFRAG + 1); return NF_STOLEN; } diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c index 34fda62..4f26ee4 100644 --- a/net/netfilter/ipvs/ip_vs_core.c +++ b/net/netfilter/ipvs/ip_vs_core.c @@ -1139,12 +1139,6 @@ ip_vs_out(unsigned int hooknum, struct sk_buff *skb, int af) ip_vs_fill_iph_skb(af, skb, &iph); #ifdef CONFIG_IP_VS_IPV6 if (af == AF_INET6) { - if (!iph.fragoffs && skb_nfct_reasm(skb)) { - struct sk_buff *reasm = skb_nfct_reasm(skb); - /* Save fw mark for coming frags */ - reasm->ipvs_property = 1; - reasm->mark = skb->mark; - } if (unlikely(iph.protocol == IPPROTO_ICMPV6)) { int related; int verdict = ip_vs_out_icmp_v6(skb, &related, @@ -1614,12 +1608,6 @@ ip_vs_in(unsigned int hooknum, struct sk_buff *skb, int af) #ifdef CONFIG_IP_VS_IPV6 if (af == AF_INET6) { - if (!iph.fragoffs && skb_nfct_reasm(skb)) { - struct sk_buff *reasm = skb_nfct_reasm(skb); - /* Save fw mark for coming frags. */ - reasm->ipvs_property = 1; - reasm->mark = skb->mark; - } if (unlikely(iph.protocol == IPPROTO_ICMPV6)) { int related; int verdict = ip_vs_in_icmp_v6(skb, &related, hooknum, @@ -1671,9 +1659,8 @@ ip_vs_in(unsigned int hooknum, struct sk_buff *skb, int af) /* sorry, all this trouble for a no-hit :) */ IP_VS_DBG_PKT(12, af, pp, skb, 0, "ip_vs_in: packet continues traversal as normal"); - if (iph.fragoffs && !skb_nfct_reasm(skb)) { + if (iph.fragoffs) { /* Fragment that couldn't be mapped to a conn entry - * and don't have any pointer to a reasm skb * is missing module nf_defrag_ipv6 */ IP_VS_DBG_RL("Unhandled frag, load nf_defrag_ipv6\n"); @@ -1756,38 +1743,6 @@ ip_vs_local_request4(const struct nf_hook_ops *ops, struct sk_buff *skb, #ifdef CONFIG_IP_VS_IPV6 /* - * AF_INET6 fragment handling - * Copy info from first fragment, to the rest of them. - */ -static unsigned int -ip_vs_preroute_frag6(const struct nf_hook_ops *ops, struct sk_buff *skb, - const struct net_device *in, - const struct net_device *out, - int (*okfn)(struct sk_buff *)) -{ - struct sk_buff *reasm = skb_nfct_reasm(skb); - struct net *net; - - /* Skip if not a "replay" from nf_ct_frag6_output or first fragment. - * ipvs_property is set when checking first fragment - * in ip_vs_in() and ip_vs_out(). - */ - if (reasm) - IP_VS_DBG(2, "Fragment recv prop:%d\n", reasm->ipvs_property); - if (!reasm || !reasm->ipvs_property) - return NF_ACCEPT; - - net = skb_net(skb); - if (!net_ipvs(net)->enable) - return NF_ACCEPT; - - /* Copy stored fw mark, saved in ip_vs_{in,out} */ - skb->mark = reasm->mark; - - return NF_ACCEPT; -} - -/* * AF_INET6 handler in NF_INET_LOCAL_IN chain * Schedule and forward packets from remote clients */ @@ -1924,14 +1879,6 @@ static struct nf_hook_ops ip_vs_ops[] __read_mostly = { .priority = 100, }, #ifdef CONFIG_IP_VS_IPV6 - /* After mangle & nat fetch 2:nd fragment and following */ - { - .hook = ip_vs_preroute_frag6, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV6, - .hooknum = NF_INET_PRE_ROUTING, - .priority = NF_IP6_PRI_NAT_DST + 1, - }, /* After packet filtering, change source only for VS/NAT */ { .hook = ip_vs_reply6, diff --git a/net/netfilter/ipvs/ip_vs_pe_sip.c b/net/netfilter/ipvs/ip_vs_pe_sip.c index 9ef22bd..bed5f70 100644 --- a/net/netfilter/ipvs/ip_vs_pe_sip.c +++ b/net/netfilter/ipvs/ip_vs_pe_sip.c @@ -65,7 +65,6 @@ static int get_callid(const char *dptr, unsigned int dataoff, static int ip_vs_sip_fill_param(struct ip_vs_conn_param *p, struct sk_buff *skb) { - struct sk_buff *reasm = skb_nfct_reasm(skb); struct ip_vs_iphdr iph; unsigned int dataoff, datalen, matchoff, matchlen; const char *dptr; @@ -79,15 +78,10 @@ ip_vs_sip_fill_param(struct ip_vs_conn_param *p, struct sk_buff *skb) /* todo: IPv6 fragments: * I think this only should be done for the first fragment. /HS */ - if (reasm) { - skb = reasm; - dataoff = iph.thoff_reasm + sizeof(struct udphdr); - } else - dataoff = iph.len + sizeof(struct udphdr); + dataoff = iph.len + sizeof(struct udphdr); if (dataoff >= skb->len) return -EINVAL; - /* todo: Check if this will mess-up the reasm skb !!! /HS */ retc = skb_linearize(skb); if (retc < 0) return retc; -- 2.7.4