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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /net/bridge/netfilter/nft_reject_bridge.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'net/bridge/netfilter/nft_reject_bridge.c')
-rw-r--r-- | net/bridge/netfilter/nft_reject_bridge.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/net/bridge/netfilter/nft_reject_bridge.c b/net/bridge/netfilter/nft_reject_bridge.c new file mode 100644 index 000000000..71b54fed7 --- /dev/null +++ b/net/bridge/netfilter/nft_reject_bridge.c @@ -0,0 +1,216 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2014 Pablo Neira Ayuso <pablo@netfilter.org> + */ + +#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_reject.h> +#include <net/netfilter/ipv4/nf_reject.h> +#include <net/netfilter/ipv6/nf_reject.h> +#include <linux/ip.h> +#include <net/ip.h> +#include <net/ip6_checksum.h> +#include <linux/netfilter_bridge.h> +#include <linux/netfilter_ipv6.h> +#include "../br_private.h" + +static void nft_reject_br_push_etherhdr(struct sk_buff *oldskb, + struct sk_buff *nskb) +{ + struct ethhdr *eth; + + eth = skb_push(nskb, ETH_HLEN); + skb_reset_mac_header(nskb); + ether_addr_copy(eth->h_source, eth_hdr(oldskb)->h_dest); + ether_addr_copy(eth->h_dest, eth_hdr(oldskb)->h_source); + eth->h_proto = eth_hdr(oldskb)->h_proto; + skb_pull(nskb, ETH_HLEN); + + if (skb_vlan_tag_present(oldskb)) { + u16 vid = skb_vlan_tag_get(oldskb); + + __vlan_hwaccel_put_tag(nskb, oldskb->vlan_proto, vid); + } +} + +/* We cannot use oldskb->dev, it can be either bridge device (NF_BRIDGE INPUT) + * or the bridge port (NF_BRIDGE PREROUTING). + */ +static void nft_reject_br_send_v4_tcp_reset(struct net *net, + struct sk_buff *oldskb, + const struct net_device *dev, + int hook) +{ + struct sk_buff *nskb; + + nskb = nf_reject_skb_v4_tcp_reset(net, oldskb, NULL, hook); + if (!nskb) + return; + + nft_reject_br_push_etherhdr(oldskb, nskb); + + br_forward(br_port_get_rcu(dev), nskb, false, true); +} + +static void nft_reject_br_send_v4_unreach(struct net *net, + struct sk_buff *oldskb, + const struct net_device *dev, + int hook, u8 code) +{ + struct sk_buff *nskb; + + nskb = nf_reject_skb_v4_unreach(net, oldskb, NULL, hook, code); + if (!nskb) + return; + + nft_reject_br_push_etherhdr(oldskb, nskb); + + br_forward(br_port_get_rcu(dev), nskb, false, true); +} + +static void nft_reject_br_send_v6_tcp_reset(struct net *net, + struct sk_buff *oldskb, + const struct net_device *dev, + int hook) +{ + struct sk_buff *nskb; + + nskb = nf_reject_skb_v6_tcp_reset(net, oldskb, NULL, hook); + if (!nskb) + return; + + nft_reject_br_push_etherhdr(oldskb, nskb); + + br_forward(br_port_get_rcu(dev), nskb, false, true); +} + + +static void nft_reject_br_send_v6_unreach(struct net *net, + struct sk_buff *oldskb, + const struct net_device *dev, + int hook, u8 code) +{ + struct sk_buff *nskb; + + nskb = nf_reject_skb_v6_unreach(net, oldskb, NULL, hook, code); + if (!nskb) + return; + + nft_reject_br_push_etherhdr(oldskb, nskb); + + br_forward(br_port_get_rcu(dev), nskb, false, true); +} + +static void nft_reject_bridge_eval(const struct nft_expr *expr, + struct nft_regs *regs, + const struct nft_pktinfo *pkt) +{ + struct nft_reject *priv = nft_expr_priv(expr); + const unsigned char *dest = eth_hdr(pkt->skb)->h_dest; + + if (is_broadcast_ether_addr(dest) || + is_multicast_ether_addr(dest)) + goto out; + + switch (eth_hdr(pkt->skb)->h_proto) { + case htons(ETH_P_IP): + switch (priv->type) { + case NFT_REJECT_ICMP_UNREACH: + nft_reject_br_send_v4_unreach(nft_net(pkt), pkt->skb, + nft_in(pkt), + nft_hook(pkt), + priv->icmp_code); + break; + case NFT_REJECT_TCP_RST: + nft_reject_br_send_v4_tcp_reset(nft_net(pkt), pkt->skb, + nft_in(pkt), + nft_hook(pkt)); + break; + case NFT_REJECT_ICMPX_UNREACH: + nft_reject_br_send_v4_unreach(nft_net(pkt), pkt->skb, + nft_in(pkt), + nft_hook(pkt), + nft_reject_icmp_code(priv->icmp_code)); + break; + } + break; + case htons(ETH_P_IPV6): + switch (priv->type) { + case NFT_REJECT_ICMP_UNREACH: + nft_reject_br_send_v6_unreach(nft_net(pkt), pkt->skb, + nft_in(pkt), + nft_hook(pkt), + priv->icmp_code); + break; + case NFT_REJECT_TCP_RST: + nft_reject_br_send_v6_tcp_reset(nft_net(pkt), pkt->skb, + nft_in(pkt), + nft_hook(pkt)); + break; + case NFT_REJECT_ICMPX_UNREACH: + nft_reject_br_send_v6_unreach(nft_net(pkt), pkt->skb, + nft_in(pkt), + nft_hook(pkt), + nft_reject_icmpv6_code(priv->icmp_code)); + break; + } + break; + default: + /* No explicit way to reject this protocol, drop it. */ + break; + } +out: + regs->verdict.code = NF_DROP; +} + +static int nft_reject_bridge_validate(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nft_data **data) +{ + return nft_chain_validate_hooks(ctx->chain, (1 << NF_BR_PRE_ROUTING) | + (1 << NF_BR_LOCAL_IN)); +} + +static struct nft_expr_type nft_reject_bridge_type; +static const struct nft_expr_ops nft_reject_bridge_ops = { + .type = &nft_reject_bridge_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_reject)), + .eval = nft_reject_bridge_eval, + .init = nft_reject_init, + .dump = nft_reject_dump, + .validate = nft_reject_bridge_validate, + .reduce = NFT_REDUCE_READONLY, +}; + +static struct nft_expr_type nft_reject_bridge_type __read_mostly = { + .family = NFPROTO_BRIDGE, + .name = "reject", + .ops = &nft_reject_bridge_ops, + .policy = nft_reject_policy, + .maxattr = NFTA_REJECT_MAX, + .owner = THIS_MODULE, +}; + +static int __init nft_reject_bridge_module_init(void) +{ + return nft_register_expr(&nft_reject_bridge_type); +} + +static void __exit nft_reject_bridge_module_exit(void) +{ + nft_unregister_expr(&nft_reject_bridge_type); +} + +module_init(nft_reject_bridge_module_init); +module_exit(nft_reject_bridge_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>"); +MODULE_ALIAS_NFT_AF_EXPR(AF_BRIDGE, "reject"); +MODULE_DESCRIPTION("Reject packets from bridge via nftables"); |