diff options
Diffstat (limited to 'net/netfilter/nf_conntrack_proto_icmpv6.c')
| -rw-r--r-- | net/netfilter/nf_conntrack_proto_icmpv6.c | 359 |
1 files changed, 359 insertions, 0 deletions
diff --git a/net/netfilter/nf_conntrack_proto_icmpv6.c b/net/netfilter/nf_conntrack_proto_icmpv6.c new file mode 100644 index 000000000..1020d6760 --- /dev/null +++ b/net/netfilter/nf_conntrack_proto_icmpv6.c @@ -0,0 +1,359 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C)2003,2004 USAGI/WIDE Project + * + * Author: + * Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp> + */ + +#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 +}; + +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 */ +}; |