// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C)2003,2004 USAGI/WIDE Project
*
* Author:
* Yasuyuki Kozakai @USAGI <[email protected]>
*/
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/module.h>
#include <linux/netfilter.h>
#include <linux/in6.h>
#include <linux/icmpv6.h>
#include <linux/ipv6.h>
#include <net/ipv6.h>
#include <net/ip6_checksum.h>
#include <linux/seq_file.h>
#include <linux/netfilter_ipv6.h>
#include <net/netfilter/nf_conntrack_tuple.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_timeout.h>
#include <net/netfilter/nf_conntrack_zones.h>
#include <net/netfilter/nf_log.h>
#include "nf_internals.h"
static const unsigned int nf_ct_icmpv6_timeout = 30*HZ;
bool icmpv6_pkt_to_tuple(const struct sk_buff *skb,
unsigned int dataoff,
struct net *net,
struct nf_conntrack_tuple *tuple)
{
const struct icmp6hdr *hp;
struct icmp6hdr _hdr;
hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
if (hp == NULL)
return false;
tuple->dst.u.icmp.type = hp->icmp6_type;
tuple->src.u.icmp.id = hp->icmp6_identifier;
tuple->dst.u.icmp.code = hp->icmp6_code;
return true;
}
/* Add 1; spaces filled with 0. */
static const u_int8_t invmap[] = {
[ICMPV6_ECHO_REQUEST - 128] = ICMPV6_ECHO_REPLY + 1,
[ICMPV6_ECHO_REPLY - 128] = ICMPV6_ECHO_REQUEST + 1,
[ICMPV6_NI_QUERY - 128] = ICMPV6_NI_REPLY + 1,
[ICMPV6_NI_REPLY - 128] = ICMPV6_NI_QUERY + 1
};
static const u_int8_t noct_valid_new[] = {
[ICMPV6_MGM_QUERY - 130] = 1,
[ICMPV6_MGM_REPORT - 130] = 1,
[ICMPV6_MGM_REDUCTION - 130] = 1,
[NDISC_ROUTER_SOLICITATION - 130] = 1,
[NDISC_ROUTER_ADVERTISEMENT - 130] = 1,
[NDISC_NEIGHBOUR_SOLICITATION - 130] = 1,
[NDISC_NEIGHBOUR_ADVERTISEMENT - 130] = 1,
[ICMPV6_MLD2_REPORT - 130] = 1,
[ICMPV6_MRDISC_ADV - 130] = 1,
[ICMPV6_MRDISC_SOL - 130] = 1
};
bool nf_conntrack_invert_icmpv6_tuple(struct nf_conntrack_tuple *tuple,
const struct nf_conntrack_tuple *orig)
{
int type = orig->dst.u.icmp.type - 128;
if (type < 0 || type >= sizeof(invmap) || !invmap[type])
return false;
tuple->src.u.icmp.id = orig->src.u.icmp.id;
tuple->dst.u.icmp.type = invmap[type] - 1;
tuple->dst.u.icmp.code = orig->dst.u.icmp.code;
return true;
}
static unsigned int *icmpv6_get_timeouts(struct net *net)
{
return &nf_icmpv6_pernet(net)->timeout;
}
/* Returns verdict for packet, or -1 for invalid. */
int nf_conntrack_icmpv6_packet(struct nf_conn *ct,
struct sk_buff *skb,
enum ip_conntrack_info ctinfo,
const struct nf_hook_state *state)
{
unsigned int *timeout = nf_ct_timeout_lookup(ct);
static const u8 valid_new[] = {
[ICMPV6_ECHO_REQUEST - 128] = 1,
[ICMPV6_NI_QUERY - 128] = 1
};
if (state->pf != NFPROTO_IPV6)
return -NF_ACCEPT;
if (!nf_ct_is_confirmed(ct)) {
int type = ct->tuplehash[0].tuple.dst.u.icmp.type - 128;
if (type < 0 || type >= sizeof(valid_new) || !valid_new[type]) {
/* Can't create a new ICMPv6 `conn' with this. */
pr_debug("icmpv6: can't create new conn with type %u\n",
type + 128);
nf_ct_dump_tuple_ipv6(&ct->tuplehash[0].tuple);
return -NF_ACCEPT;
}
}
if (!timeout)
timeout = icmpv6_get_timeouts(nf_ct_net(ct));
/* Do not immediately delete the connection after the first
successful reply to avoid excessive conntrackd traffic
and also to handle correctly ICMP echo reply duplicates. */
nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
return NF_ACCEPT;
}
static void icmpv6_error_log(const struct sk_buff *skb,
const struct nf_hook_state *state,
const char *msg)
{
nf_l4proto_log_invalid(skb, state, IPPROTO_ICMPV6, "%s", msg);
}
static noinline_for_stack int
nf_conntrack_icmpv6_redirect(struct nf_conn *tmpl, struct sk_buff *skb,
unsigned int dataoff,
const struct nf_hook_state *state)
{
u8 hl = ipv6_hdr(skb)->hop_limit;
union nf_inet_addr outer_daddr;
union {
struct nd_opt_hdr nd_opt;
struct rd_msg rd_msg;
} tmp;
const struct nd_opt_hdr *nd_opt;
const struct rd_msg *rd_msg;
rd_msg = skb_header_pointer(skb, dataoff, sizeof(*rd_msg), &tmp.rd_msg);
if (!rd_msg) {
icmpv6_error_log(skb, state, "short redirect");
return -NF_ACCEPT;
}
if (rd_msg->icmph.icmp6_code != 0)
return NF_ACCEPT;
if (hl != 255 || !(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) {
icmpv6_error_log(skb, state, "invalid saddr or hoplimit for redirect");
return -NF_ACCEPT;
}
dataoff += sizeof(*rd_msg);
/* warning: rd_msg no longer usable after this call */
nd_opt = skb_header_pointer(skb, dataoff, sizeof(*nd_opt), &tmp.nd_opt);
if (!nd_opt || nd_opt->nd_opt_len == 0) {
icmpv6_error_log(skb, state, "redirect without options");
return -NF_ACCEPT;
}
/* We could call ndisc_parse_options(), but it would need
* skb_linearize() and a bit more work.
*/
if (nd_opt->nd_opt_type != ND_OPT_REDIRECT_HDR)
return NF_ACCEPT;
memcpy(&outer_daddr.ip6, &ipv6_hdr(skb)->daddr,
sizeof(outer_daddr.ip6));
dataoff += 8;
return nf_conntrack_inet_error(tmpl, skb, dataoff, state,
IPPROTO_ICMPV6, &outer_daddr);
}
int nf_conntrack_icmpv6_error(struct nf_conn *tmpl,
struct sk_buff *skb,
unsigned int dataoff,
const struct nf_hook_state *state)
{
union nf_inet_addr outer_daddr;
const struct icmp6hdr *icmp6h;
struct icmp6hdr _ih;
int type;
icmp6h = skb_header_pointer(skb, dataoff, sizeof(_ih), &_ih);
if (icmp6h == NULL) {
icmpv6_error_log(skb, state, "short packet");
return -NF_ACCEPT;
}
if (state->hook == NF_INET_PRE_ROUTING &&
state->net->ct.sysctl_checksum &&
nf_ip6_checksum(skb, state->hook, dataoff, IPPROTO_ICMPV6)) {
icmpv6_error_log(skb, state, "ICMPv6 checksum failed");
return -NF_ACCEPT;
}
type = icmp6h->icmp6_type - 130;
if (type >= 0 && type < sizeof(noct_valid_new) &&
noct_valid_new[type]) {
nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
return NF_ACCEPT;
}
if (icmp6h->icmp6_type == NDISC_REDIRECT)
return nf_conntrack_icmpv6_redirect(tmpl, skb, dataoff, state);
/* is not error message ? */
if (icmp6h->icmp6_type >= 128)
return NF_ACCEPT;
memcpy(&outer_daddr.ip6, &ipv6_hdr(skb)->daddr,
sizeof(outer_daddr.ip6));
dataoff += sizeof(*icmp6h);
return nf_conntrack_inet_error(tmpl, skb, dataoff, state,
IPPROTO_ICMPV6, &outer_daddr);
}
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_conntrack.h>
static int icmpv6_tuple_to_nlattr(struct sk_buff *skb,
const struct nf_conntrack_tuple *t)
{
if (nla_put_be16(skb, CTA_PROTO_ICMPV6_ID, t->src.u.icmp.id) ||
nla_put_u8(skb, CTA_PROTO_ICMPV6_TYPE, t->dst.u.icmp.type) ||
nla_put_u8(skb, CTA_PROTO_ICMPV6_CODE, t->dst.u.icmp.code))
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static const struct nla_policy icmpv6_nla_policy[CTA_PROTO_MAX+1] = {
[CTA_PROTO_ICMPV6_TYPE] = { .type = NLA_U8 },
[CTA_PROTO_ICMPV6_CODE] = { .type = NLA_U8 },
[CTA_PROTO_ICMPV6_ID] = { .type = NLA_U16 },
};
static int icmpv6_nlattr_to_tuple(struct nlattr *tb[],
struct nf_conntrack_tuple *tuple,
u_int32_t flags)
{
if (flags & CTA_FILTER_FLAG(CTA_PROTO_ICMPV6_TYPE)) {
if (!tb[CTA_PROTO_ICMPV6_TYPE])
return -EINVAL;
tuple->dst.u.icmp.type = nla_get_u8(tb[CTA_PROTO_ICMPV6_TYPE]);
if (tuple->dst.u.icmp.type < 128 ||
tuple->dst.u.icmp.type - 128 >= sizeof(invmap) ||
!invmap[tuple->dst.u.icmp.type - 128])
return -EINVAL;
}
if (flags & CTA_FILTER_FLAG(CTA_PROTO_ICMPV6_CODE)) {
if (!tb[CTA_PROTO_ICMPV6_CODE])
return -EINVAL;
tuple->dst.u.icmp.code = nla_get_u8(tb[CTA_PROTO_ICMPV6_CODE]);
}
if (flags & CTA_FILTER_FLAG(CTA_PROTO_ICMPV6_ID)) {
if (!tb[CTA_PROTO_ICMPV6_ID])
return -EINVAL;
tuple->src.u.icmp.id = nla_get_be16(tb[CTA_PROTO_ICMPV6_ID]);
}
return 0;
}
static unsigned int icmpv6_nlattr_tuple_size(void)
{
static unsigned int size __read_mostly;
if (!size)
size = nla_policy_len(icmpv6_nla_policy, CTA_PROTO_MAX + 1);
return size;
}
#endif
#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_cttimeout.h>
static int icmpv6_timeout_nlattr_to_obj(struct nlattr *tb[],
struct net *net, void *data)
{
unsigned int *timeout = data;
struct nf_icmp_net *in = nf_icmpv6_pernet(net);
if (!timeout)
timeout = icmpv6_get_timeouts(net);
if (tb[CTA_TIMEOUT_ICMPV6_TIMEOUT]) {
*timeout =
ntohl(nla_get_be32(tb[CTA_TIMEOUT_ICMPV6_TIMEOUT])) * HZ;
} else {
/* Set default ICMPv6 timeout. */
*timeout = in->timeout;
}
return 0;
}
static int
icmpv6_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
{
const unsigned int *timeout = data;
if (nla_put_be32(skb, CTA_TIMEOUT_ICMPV6_TIMEOUT, htonl(*timeout / HZ)))
goto nla_put_failure;
return 0;
nla_put_failure:
return -ENOSPC;
}
static const struct nla_policy
icmpv6_timeout_nla_policy[CTA_TIMEOUT_ICMPV6_MAX+1] = {
[CTA_TIMEOUT_ICMPV6_TIMEOUT] = { .type = NLA_U32 },
};
#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
void nf_conntrack_icmpv6_init_net(struct net *net)
{
struct nf_icmp_net *in = nf_icmpv6_pernet(net);
in->timeout = nf_ct_icmpv6_timeout;
}
const struct nf_conntrack_l4proto nf_conntrack_l4proto_icmpv6 =
{
.l4proto = IPPROTO_ICMPV6,
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
.tuple_to_nlattr = icmpv6_tuple_to_nlattr,
.nlattr_tuple_size = icmpv6_nlattr_tuple_size,
.nlattr_to_tuple = icmpv6_nlattr_to_tuple,
.nla_policy = icmpv6_nla_policy,
#endif
#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
.ctnl_timeout = {
.nlattr_to_obj = icmpv6_timeout_nlattr_to_obj,
.obj_to_nlattr = icmpv6_timeout_obj_to_nlattr,
.nlattr_max = CTA_TIMEOUT_ICMP_MAX,
.obj_size = sizeof(unsigned int),
.nla_policy = icmpv6_timeout_nla_policy,
},
#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
};
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