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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/ipv4/netfilter/ipt_REJECT.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 '')
-rw-r--r-- | net/ipv4/netfilter/ipt_REJECT.c | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/ipt_REJECT.c b/net/ipv4/netfilter/ipt_REJECT.c new file mode 100644 index 000000000..4b8840734 --- /dev/null +++ b/net/ipv4/netfilter/ipt_REJECT.c @@ -0,0 +1,111 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * This is a module which is used for rejecting packets. + */ + +/* (C) 1999-2001 Paul `Rusty' Russell + * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include <linux/module.h> +#include <linux/skbuff.h> +#include <linux/slab.h> +#include <linux/ip.h> +#include <linux/udp.h> +#include <linux/icmp.h> +#include <net/icmp.h> +#include <linux/netfilter/x_tables.h> +#include <linux/netfilter_ipv4/ip_tables.h> +#include <linux/netfilter_ipv4/ipt_REJECT.h> +#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) +#include <linux/netfilter_bridge.h> +#endif + +#include <net/netfilter/ipv4/nf_reject.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); +MODULE_DESCRIPTION("Xtables: packet \"rejection\" target for IPv4"); + +static unsigned int +reject_tg(struct sk_buff *skb, const struct xt_action_param *par) +{ + const struct ipt_reject_info *reject = par->targinfo; + int hook = xt_hooknum(par); + + switch (reject->with) { + case IPT_ICMP_NET_UNREACHABLE: + nf_send_unreach(skb, ICMP_NET_UNREACH, hook); + break; + case IPT_ICMP_HOST_UNREACHABLE: + nf_send_unreach(skb, ICMP_HOST_UNREACH, hook); + break; + case IPT_ICMP_PROT_UNREACHABLE: + nf_send_unreach(skb, ICMP_PROT_UNREACH, hook); + break; + case IPT_ICMP_PORT_UNREACHABLE: + nf_send_unreach(skb, ICMP_PORT_UNREACH, hook); + break; + case IPT_ICMP_NET_PROHIBITED: + nf_send_unreach(skb, ICMP_NET_ANO, hook); + break; + case IPT_ICMP_HOST_PROHIBITED: + nf_send_unreach(skb, ICMP_HOST_ANO, hook); + break; + case IPT_ICMP_ADMIN_PROHIBITED: + nf_send_unreach(skb, ICMP_PKT_FILTERED, hook); + break; + case IPT_TCP_RESET: + nf_send_reset(xt_net(par), par->state->sk, skb, hook); + break; + case IPT_ICMP_ECHOREPLY: + /* Doesn't happen. */ + break; + } + + return NF_DROP; +} + +static int reject_tg_check(const struct xt_tgchk_param *par) +{ + const struct ipt_reject_info *rejinfo = par->targinfo; + const struct ipt_entry *e = par->entryinfo; + + if (rejinfo->with == IPT_ICMP_ECHOREPLY) { + pr_info_ratelimited("ECHOREPLY no longer supported.\n"); + return -EINVAL; + } else if (rejinfo->with == IPT_TCP_RESET) { + /* Must specify that it's a TCP packet */ + if (e->ip.proto != IPPROTO_TCP || + (e->ip.invflags & XT_INV_PROTO)) { + pr_info_ratelimited("TCP_RESET invalid for non-tcp\n"); + return -EINVAL; + } + } + return 0; +} + +static struct xt_target reject_tg_reg __read_mostly = { + .name = "REJECT", + .family = NFPROTO_IPV4, + .target = reject_tg, + .targetsize = sizeof(struct ipt_reject_info), + .table = "filter", + .hooks = (1 << NF_INET_LOCAL_IN) | (1 << NF_INET_FORWARD) | + (1 << NF_INET_LOCAL_OUT), + .checkentry = reject_tg_check, + .me = THIS_MODULE, +}; + +static int __init reject_tg_init(void) +{ + return xt_register_target(&reject_tg_reg); +} + +static void __exit reject_tg_exit(void) +{ + xt_unregister_target(&reject_tg_reg); +} + +module_init(reject_tg_init); +module_exit(reject_tg_exit); |