diff options
Diffstat (limited to 'net/bridge/netfilter')
| -rw-r--r-- | net/bridge/netfilter/Kconfig | 20 | ||||
| -rw-r--r-- | net/bridge/netfilter/Makefile | 4 | ||||
| -rw-r--r-- | net/bridge/netfilter/ebt_dnat.c | 2 | ||||
| -rw-r--r-- | net/bridge/netfilter/ebt_redirect.c | 2 | ||||
| -rw-r--r-- | net/bridge/netfilter/ebt_snat.c | 2 | ||||
| -rw-r--r-- | net/bridge/netfilter/nf_conntrack_bridge.c | 435 | ||||
| -rw-r--r-- | net/bridge/netfilter/nft_meta_bridge.c | 163 |
7 files changed, 625 insertions, 3 deletions
diff --git a/net/bridge/netfilter/Kconfig b/net/bridge/netfilter/Kconfig index 36a98d36d339..154fa558bb90 100644 --- a/net/bridge/netfilter/Kconfig +++ b/net/bridge/netfilter/Kconfig @@ -9,6 +9,12 @@ menuconfig NF_TABLES_BRIDGE bool "Ethernet Bridge nf_tables support" if NF_TABLES_BRIDGE + +config NFT_BRIDGE_META + tristate "Netfilter nf_table bridge meta support" + help + Add support for bridge dedicated meta key. + config NFT_BRIDGE_REJECT tristate "Netfilter nf_tables bridge reject support" depends on NFT_REJECT && NFT_REJECT_IPV4 && NFT_REJECT_IPV6 @@ -19,6 +25,20 @@ config NF_LOG_BRIDGE tristate "Bridge packet logging" select NF_LOG_COMMON +config NF_CONNTRACK_BRIDGE + tristate "IPv4/IPV6 bridge connection tracking support" + depends on NF_CONNTRACK + default n + help + Connection tracking keeps a record of what packets have passed + through your machine, in order to figure out how they are related + into connections. This is used to enhance packet filtering via + stateful policies. Enable this if you want native tracking from + the bridge. This provides a replacement for the `br_netfilter' + infrastructure. + + To compile it as a module, choose M here. If unsure, say N. + endif # NF_TABLES_BRIDGE menuconfig BRIDGE_NF_EBTABLES diff --git a/net/bridge/netfilter/Makefile b/net/bridge/netfilter/Makefile index 9b868861f21a..8e2c5759d964 100644 --- a/net/bridge/netfilter/Makefile +++ b/net/bridge/netfilter/Makefile @@ -3,8 +3,12 @@ # Makefile for the netfilter modules for Link Layer filtering on a bridge. # +obj-$(CONFIG_NFT_BRIDGE_META) += nft_meta_bridge.o obj-$(CONFIG_NFT_BRIDGE_REJECT) += nft_reject_bridge.o +# connection tracking +obj-$(CONFIG_NF_CONNTRACK_BRIDGE) += nf_conntrack_bridge.o + # packet logging obj-$(CONFIG_NF_LOG_BRIDGE) += nf_log_bridge.o diff --git a/net/bridge/netfilter/ebt_dnat.c b/net/bridge/netfilter/ebt_dnat.c index eeae23a73c6a..ed91ea31978a 100644 --- a/net/bridge/netfilter/ebt_dnat.c +++ b/net/bridge/netfilter/ebt_dnat.c @@ -22,7 +22,7 @@ ebt_dnat_tg(struct sk_buff *skb, const struct xt_action_param *par) const struct ebt_nat_info *info = par->targinfo; struct net_device *dev; - if (!skb_make_writable(skb, 0)) + if (skb_ensure_writable(skb, ETH_ALEN)) return EBT_DROP; ether_addr_copy(eth_hdr(skb)->h_dest, info->mac); diff --git a/net/bridge/netfilter/ebt_redirect.c b/net/bridge/netfilter/ebt_redirect.c index 53ef08e6765f..0cad62a4052b 100644 --- a/net/bridge/netfilter/ebt_redirect.c +++ b/net/bridge/netfilter/ebt_redirect.c @@ -21,7 +21,7 @@ ebt_redirect_tg(struct sk_buff *skb, const struct xt_action_param *par) { const struct ebt_redirect_info *info = par->targinfo; - if (!skb_make_writable(skb, 0)) + if (skb_ensure_writable(skb, ETH_ALEN)) return EBT_DROP; if (xt_hooknum(par) != NF_BR_BROUTING) diff --git a/net/bridge/netfilter/ebt_snat.c b/net/bridge/netfilter/ebt_snat.c index 700d338d5ddb..27443bf229a3 100644 --- a/net/bridge/netfilter/ebt_snat.c +++ b/net/bridge/netfilter/ebt_snat.c @@ -22,7 +22,7 @@ ebt_snat_tg(struct sk_buff *skb, const struct xt_action_param *par) { const struct ebt_nat_info *info = par->targinfo; - if (!skb_make_writable(skb, 0)) + if (skb_ensure_writable(skb, ETH_ALEN * 2)) return EBT_DROP; ether_addr_copy(eth_hdr(skb)->h_source, info->mac); diff --git a/net/bridge/netfilter/nf_conntrack_bridge.c b/net/bridge/netfilter/nf_conntrack_bridge.c new file mode 100644 index 000000000000..4f5444d2a526 --- /dev/null +++ b/net/bridge/netfilter/nf_conntrack_bridge.c @@ -0,0 +1,435 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include <linux/types.h> +#include <linux/ip.h> +#include <linux/netfilter.h> +#include <linux/netfilter_ipv6.h> +#include <linux/netfilter_bridge.h> +#include <linux/module.h> +#include <linux/skbuff.h> +#include <linux/icmp.h> +#include <linux/sysctl.h> +#include <net/route.h> +#include <net/ip.h> + +#include <net/netfilter/nf_conntrack.h> +#include <net/netfilter/nf_conntrack_core.h> +#include <net/netfilter/nf_conntrack_helper.h> +#include <net/netfilter/nf_conntrack_bridge.h> + +#include <linux/netfilter/nf_tables.h> +#include <net/netfilter/ipv6/nf_defrag_ipv6.h> +#include <net/netfilter/nf_tables.h> + +#include "../br_private.h" + +/* Best effort variant of ip_do_fragment which preserves geometry, unless skbuff + * has been linearized or cloned. + */ +static int nf_br_ip_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; + unsigned int hlen, ll_rs, mtu; + struct ip_frag_state state; + struct iphdr *iph; + int err; + + /* for offloaded checksums cleanup checksum before fragmentation */ + if (skb->ip_summed == CHECKSUM_PARTIAL && + (err = skb_checksum_help(skb))) + goto blackhole; + + iph = ip_hdr(skb); + + /* + * Setup starting values + */ + + hlen = iph->ihl * 4; + frag_max_size -= hlen; + ll_rs = LL_RESERVED_SPACE(skb->dev); + mtu = skb->dev->mtu; + + if (skb_has_frag_list(skb)) { + unsigned int first_len = skb_pagelen(skb); + struct ip_fraglist_iter iter; + struct sk_buff *frag; + + if (first_len - hlen > mtu || + skb_headroom(skb) < ll_rs) + goto blackhole; + + if (skb_cloned(skb)) + goto slow_path; + + skb_walk_frags(skb, frag) { + if (frag->len > mtu || + skb_headroom(frag) < hlen + ll_rs) + goto blackhole; + + if (skb_shared(frag)) + goto slow_path; + } + + ip_fraglist_init(skb, iph, hlen, &iter); + + for (;;) { + if (iter.frag) + ip_fraglist_prepare(skb, &iter); + + err = output(net, sk, data, skb); + if (err || !iter.frag) + break; + + skb = ip_fraglist_next(&iter); + } + 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. + */ + ip_frag_init(skb, hlen, ll_rs, frag_max_size, &state); + + while (state.left > 0) { + struct sk_buff *skb2; + + skb2 = ip_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; +} + +/* ip_defrag() expects IPCB() in place. */ +static void br_skb_cb_save(struct sk_buff *skb, struct br_input_skb_cb *cb, + size_t inet_skb_parm_size) +{ + memcpy(cb, skb->cb, sizeof(*cb)); + memset(skb->cb, 0, inet_skb_parm_size); +} + +static void br_skb_cb_restore(struct sk_buff *skb, + const struct br_input_skb_cb *cb, + u16 fragsz) +{ + memcpy(skb->cb, cb, sizeof(*cb)); + BR_INPUT_SKB_CB(skb)->frag_max_size = fragsz; +} + +static unsigned int nf_ct_br_defrag4(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; + + if (!ip_is_fragment(ip_hdr(skb))) + return NF_ACCEPT; + + 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 inet_skb_parm)); + local_bh_disable(); + err = ip_defrag(state->net, skb, + IP_DEFRAG_CONNTRACK_BRIDGE_IN + zone_id); + local_bh_enable(); + if (!err) { + br_skb_cb_restore(skb, &cb, IPCB(skb)->frag_max_size); + skb->ignore_df = 1; + return NF_ACCEPT; + } + + 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; + int nhoff, len; + + nhoff = skb_network_offset(skb); + iph = ip_hdr(skb); + if (iph->ihl < 5 || + iph->version != 4) + return -1; + + 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; +} + +static unsigned int nf_ct_bridge_pre(void *priv, struct sk_buff *skb, + const struct nf_hook_state *state) +{ + struct nf_hook_state bridge_state = *state; + enum ip_conntrack_info ctinfo; + struct nf_conn *ct; + u32 len; + int ret; + + ct = nf_ct_get(skb, &ctinfo); + if ((ct && !nf_ct_is_template(ct)) || + ctinfo == IP_CT_UNTRACKED) + return NF_ACCEPT; + + switch (skb->protocol) { + case htons(ETH_P_IP): + if (!pskb_may_pull(skb, sizeof(struct iphdr))) + return NF_ACCEPT; + + len = ntohs(ip_hdr(skb)->tot_len); + if (pskb_trim_rcsum(skb, len)) + return NF_ACCEPT; + + if (nf_ct_br_ip_check(skb)) + return NF_ACCEPT; + + bridge_state.pf = NFPROTO_IPV4; + ret = nf_ct_br_defrag4(skb, &bridge_state); + break; + case htons(ETH_P_IPV6): + 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; + } + + if (ret != NF_ACCEPT) + return ret; + + return nf_conntrack_in(skb, &bridge_state); +} + +static void nf_ct_bridge_frag_save(struct sk_buff *skb, + struct nf_ct_bridge_frag_data *data) +{ + if (skb_vlan_tag_present(skb)) { + data->vlan_present = true; + data->vlan_tci = skb->vlan_tci; + data->vlan_proto = skb->vlan_proto; + } else { + data->vlan_present = false; + } + skb_copy_from_linear_data_offset(skb, -ETH_HLEN, data->mac, ETH_HLEN); +} + +static unsigned int +nf_ct_bridge_refrag(struct sk_buff *skb, const struct nf_hook_state *state, + int (*output)(struct net *, struct sock *sk, + const struct nf_ct_bridge_frag_data *data, + struct sk_buff *)) +{ + struct nf_ct_bridge_frag_data data; + + if (!BR_INPUT_SKB_CB(skb)->frag_max_size) + return NF_ACCEPT; + + nf_ct_bridge_frag_save(skb, &data); + switch (skb->protocol) { + case htons(ETH_P_IP): + nf_br_ip_fragment(state->net, state->sk, skb, &data, output); + break; + case htons(ETH_P_IPV6): + nf_br_ip6_fragment(state->net, state->sk, skb, &data, output); + break; + default: + WARN_ON_ONCE(1); + return NF_DROP; + } + + return NF_STOLEN; +} + +/* Actually only slow path refragmentation needs this. */ +static int nf_ct_bridge_frag_restore(struct sk_buff *skb, + const struct nf_ct_bridge_frag_data *data) +{ + int err; + + err = skb_cow_head(skb, ETH_HLEN); + if (err) { + kfree_skb(skb); + return -ENOMEM; + } + if (data->vlan_present) + __vlan_hwaccel_put_tag(skb, data->vlan_proto, data->vlan_tci); + else if (skb_vlan_tag_present(skb)) + __vlan_hwaccel_clear_tag(skb); + + skb_copy_to_linear_data_offset(skb, -ETH_HLEN, data->mac, ETH_HLEN); + skb_reset_mac_header(skb); + + return 0; +} + +static int nf_ct_bridge_refrag_post(struct net *net, struct sock *sk, + const struct nf_ct_bridge_frag_data *data, + struct sk_buff *skb) +{ + int err; + + err = nf_ct_bridge_frag_restore(skb, data); + if (err < 0) + return err; + + return br_dev_queue_push_xmit(net, sk, skb); +} + +static unsigned int nf_ct_bridge_confirm(struct sk_buff *skb) +{ + enum ip_conntrack_info ctinfo; + struct nf_conn *ct; + int protoff; + + ct = nf_ct_get(skb, &ctinfo); + if (!ct || ctinfo == IP_CT_RELATED_REPLY) + return nf_conntrack_confirm(skb); + + switch (skb->protocol) { + case htons(ETH_P_IP): + protoff = skb_network_offset(skb) + ip_hdrlen(skb); + break; + case htons(ETH_P_IPV6): { + unsigned char pnum = ipv6_hdr(skb)->nexthdr; + __be16 frag_off; + + protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &pnum, + &frag_off); + if (protoff < 0 || (frag_off & htons(~0x7)) != 0) + return nf_conntrack_confirm(skb); + } + break; + default: + return NF_ACCEPT; + } + return nf_confirm(skb, protoff, ct, ctinfo); +} + +static unsigned int nf_ct_bridge_post(void *priv, struct sk_buff *skb, + const struct nf_hook_state *state) +{ + int ret; + + ret = nf_ct_bridge_confirm(skb); + if (ret != NF_ACCEPT) + return ret; + + return nf_ct_bridge_refrag(skb, state, nf_ct_bridge_refrag_post); +} + +static struct nf_hook_ops nf_ct_bridge_hook_ops[] __read_mostly = { + { + .hook = nf_ct_bridge_pre, + .pf = NFPROTO_BRIDGE, + .hooknum = NF_BR_PRE_ROUTING, + .priority = NF_IP_PRI_CONNTRACK, + }, + { + .hook = nf_ct_bridge_post, + .pf = NFPROTO_BRIDGE, + .hooknum = NF_BR_POST_ROUTING, + .priority = NF_IP_PRI_CONNTRACK_CONFIRM, + }, +}; + +static struct nf_ct_bridge_info bridge_info = { + .ops = nf_ct_bridge_hook_ops, + .ops_size = ARRAY_SIZE(nf_ct_bridge_hook_ops), + .me = THIS_MODULE, +}; + +static int __init nf_conntrack_l3proto_bridge_init(void) +{ + nf_ct_bridge_register(&bridge_info); + + return 0; +} + +static void __exit nf_conntrack_l3proto_bridge_fini(void) +{ + nf_ct_bridge_unregister(&bridge_info); +} + +module_init(nf_conntrack_l3proto_bridge_init); +module_exit(nf_conntrack_l3proto_bridge_fini); + +MODULE_ALIAS("nf_conntrack-" __stringify(AF_BRIDGE)); +MODULE_LICENSE("GPL"); diff --git a/net/bridge/netfilter/nft_meta_bridge.c b/net/bridge/netfilter/nft_meta_bridge.c new file mode 100644 index 000000000000..bed66f536b34 --- /dev/null +++ b/net/bridge/netfilter/nft_meta_bridge.c @@ -0,0 +1,163 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/netlink.h> +#include <linux/netfilter.h> +#include <linux/netfilter/nf_tables.h> +#include <net/netfilter/nf_tables.h> +#include <net/netfilter/nft_meta.h> +#include <linux/if_bridge.h> + +static const struct net_device * +nft_meta_get_bridge(const struct net_device *dev) +{ + if (dev && netif_is_bridge_port(dev)) + return netdev_master_upper_dev_get_rcu((struct net_device *)dev); + + return NULL; +} + +static void nft_meta_bridge_get_eval(const struct nft_expr *expr, + struct nft_regs *regs, + const struct nft_pktinfo *pkt) +{ + const struct nft_meta *priv = nft_expr_priv(expr); + const struct net_device *in = nft_in(pkt), *out = nft_out(pkt); + u32 *dest = ®s->data[priv->dreg]; + const struct net_device *br_dev; + + switch (priv->key) { + case NFT_META_BRI_IIFNAME: + br_dev = nft_meta_get_bridge(in); + if (!br_dev) + goto err; + break; + case NFT_META_BRI_OIFNAME: + br_dev = nft_meta_get_bridge(out); + if (!br_dev) + goto err; + break; + case NFT_META_BRI_IIFPVID: { + u16 p_pvid; + + br_dev = nft_meta_get_bridge(in); + if (!br_dev || !br_vlan_enabled(br_dev)) + goto err; + + br_vlan_get_pvid_rcu(in, &p_pvid); + nft_reg_store16(dest, p_pvid); + return; + } + case NFT_META_BRI_IIFVPROTO: { + u16 p_proto; + + br_dev = nft_meta_get_bridge(in); + if (!br_dev || !br_vlan_enabled(br_dev)) + goto err; + + br_vlan_get_proto(br_dev, &p_proto); + nft_reg_store16(dest, p_proto); + return; + } + default: + goto out; + } + + strncpy((char *)dest, br_dev->name, IFNAMSIZ); + return; +out: + return nft_meta_get_eval(expr, regs, pkt); +err: + regs->verdict.code = NFT_BREAK; +} + +static int nft_meta_bridge_get_init(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_meta *priv = nft_expr_priv(expr); + unsigned int len; + + priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY])); + switch (priv->key) { + case NFT_META_BRI_IIFNAME: + case NFT_META_BRI_OIFNAME: + len = IFNAMSIZ; + break; + case NFT_META_BRI_IIFPVID: + case NFT_META_BRI_IIFVPROTO: + len = sizeof(u16); + break; + default: + return nft_meta_get_init(ctx, expr, tb); + } + + priv->dreg = nft_parse_register(tb[NFTA_META_DREG]); + return nft_validate_register_store(ctx, priv->dreg, NULL, + NFT_DATA_VALUE, len); +} + +static struct nft_expr_type nft_meta_bridge_type; +static const struct nft_expr_ops nft_meta_bridge_get_ops = { + .type = &nft_meta_bridge_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_meta)), + .eval = nft_meta_bridge_get_eval, + .init = nft_meta_bridge_get_init, + .dump = nft_meta_get_dump, +}; + +static const struct nft_expr_ops nft_meta_bridge_set_ops = { + .type = &nft_meta_bridge_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_meta)), + .eval = nft_meta_set_eval, + .init = nft_meta_set_init, + .destroy = nft_meta_set_destroy, + .dump = nft_meta_set_dump, + .validate = nft_meta_set_validate, +}; + +static const struct nft_expr_ops * +nft_meta_bridge_select_ops(const struct nft_ctx *ctx, + const struct nlattr * const tb[]) +{ + if (tb[NFTA_META_KEY] == NULL) + return ERR_PTR(-EINVAL); + + if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG]) + return ERR_PTR(-EINVAL); + + if (tb[NFTA_META_DREG]) + return &nft_meta_bridge_get_ops; + + if (tb[NFTA_META_SREG]) + return &nft_meta_bridge_set_ops; + + return ERR_PTR(-EINVAL); +} + +static struct nft_expr_type nft_meta_bridge_type __read_mostly = { + .family = NFPROTO_BRIDGE, + .name = "meta", + .select_ops = nft_meta_bridge_select_ops, + .policy = nft_meta_policy, + .maxattr = NFTA_META_MAX, + .owner = THIS_MODULE, +}; + +static int __init nft_meta_bridge_module_init(void) +{ + return nft_register_expr(&nft_meta_bridge_type); +} + +static void __exit nft_meta_bridge_module_exit(void) +{ + nft_unregister_expr(&nft_meta_bridge_type); +} + +module_init(nft_meta_bridge_module_init); +module_exit(nft_meta_bridge_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("wenxu <wenxu@ucloud.cn>"); +MODULE_ALIAS_NFT_AF_EXPR(AF_BRIDGE, "meta"); |