1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C)2003,2004 USAGI/WIDE Project 4 * 5 * Author: 6 * Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp> 7 */ 8 9 #include <linux/types.h> 10 #include <linux/timer.h> 11 #include <linux/module.h> 12 #include <linux/netfilter.h> 13 #include <linux/in6.h> 14 #include <linux/icmpv6.h> 15 #include <linux/ipv6.h> 16 #include <net/ipv6.h> 17 #include <net/ip6_checksum.h> 18 #include <linux/seq_file.h> 19 #include <linux/netfilter_ipv6.h> 20 #include <net/netfilter/nf_conntrack_tuple.h> 21 #include <net/netfilter/nf_conntrack_l4proto.h> 22 #include <net/netfilter/nf_conntrack_core.h> 23 #include <net/netfilter/nf_conntrack_timeout.h> 24 #include <net/netfilter/nf_conntrack_zones.h> 25 #include <net/netfilter/nf_log.h> 26 27 #include "nf_internals.h" 28 29 static const unsigned int nf_ct_icmpv6_timeout = 30*HZ; 30 31 bool icmpv6_pkt_to_tuple(const struct sk_buff *skb, 32 unsigned int dataoff, 33 struct net *net, 34 struct nf_conntrack_tuple *tuple) 35 { 36 const struct icmp6hdr *hp; 37 struct icmp6hdr _hdr; 38 39 hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr); 40 if (hp == NULL) 41 return false; 42 tuple->dst.u.icmp.type = hp->icmp6_type; 43 tuple->src.u.icmp.id = hp->icmp6_identifier; 44 tuple->dst.u.icmp.code = hp->icmp6_code; 45 46 return true; 47 } 48 49 /* Add 1; spaces filled with 0. */ 50 static const u_int8_t invmap[] = { 51 [ICMPV6_ECHO_REQUEST - 128] = ICMPV6_ECHO_REPLY + 1, 52 [ICMPV6_ECHO_REPLY - 128] = ICMPV6_ECHO_REQUEST + 1, 53 [ICMPV6_NI_QUERY - 128] = ICMPV6_NI_REPLY + 1, 54 [ICMPV6_NI_REPLY - 128] = ICMPV6_NI_QUERY + 1 55 }; 56 57 static const u_int8_t noct_valid_new[] = { 58 [ICMPV6_MGM_QUERY - 130] = 1, 59 [ICMPV6_MGM_REPORT - 130] = 1, 60 [ICMPV6_MGM_REDUCTION - 130] = 1, 61 [NDISC_ROUTER_SOLICITATION - 130] = 1, 62 [NDISC_ROUTER_ADVERTISEMENT - 130] = 1, 63 [NDISC_NEIGHBOUR_SOLICITATION - 130] = 1, 64 [NDISC_NEIGHBOUR_ADVERTISEMENT - 130] = 1, 65 [ICMPV6_MLD2_REPORT - 130] = 1 66 }; 67 68 bool nf_conntrack_invert_icmpv6_tuple(struct nf_conntrack_tuple *tuple, 69 const struct nf_conntrack_tuple *orig) 70 { 71 int type = orig->dst.u.icmp.type - 128; 72 if (type < 0 || type >= sizeof(invmap) || !invmap[type]) 73 return false; 74 75 tuple->src.u.icmp.id = orig->src.u.icmp.id; 76 tuple->dst.u.icmp.type = invmap[type] - 1; 77 tuple->dst.u.icmp.code = orig->dst.u.icmp.code; 78 return true; 79 } 80 81 static unsigned int *icmpv6_get_timeouts(struct net *net) 82 { 83 return &nf_icmpv6_pernet(net)->timeout; 84 } 85 86 /* Returns verdict for packet, or -1 for invalid. */ 87 int nf_conntrack_icmpv6_packet(struct nf_conn *ct, 88 struct sk_buff *skb, 89 enum ip_conntrack_info ctinfo, 90 const struct nf_hook_state *state) 91 { 92 unsigned int *timeout = nf_ct_timeout_lookup(ct); 93 static const u8 valid_new[] = { 94 [ICMPV6_ECHO_REQUEST - 128] = 1, 95 [ICMPV6_NI_QUERY - 128] = 1 96 }; 97 98 if (state->pf != NFPROTO_IPV6) 99 return -NF_ACCEPT; 100 101 if (!nf_ct_is_confirmed(ct)) { 102 int type = ct->tuplehash[0].tuple.dst.u.icmp.type - 128; 103 104 if (type < 0 || type >= sizeof(valid_new) || !valid_new[type]) { 105 /* Can't create a new ICMPv6 `conn' with this. */ 106 pr_debug("icmpv6: can't create new conn with type %u\n", 107 type + 128); 108 nf_ct_dump_tuple_ipv6(&ct->tuplehash[0].tuple); 109 return -NF_ACCEPT; 110 } 111 } 112 113 if (!timeout) 114 timeout = icmpv6_get_timeouts(nf_ct_net(ct)); 115 116 /* Do not immediately delete the connection after the first 117 successful reply to avoid excessive conntrackd traffic 118 and also to handle correctly ICMP echo reply duplicates. */ 119 nf_ct_refresh_acct(ct, ctinfo, skb, *timeout); 120 121 return NF_ACCEPT; 122 } 123 124 125 static void icmpv6_error_log(const struct sk_buff *skb, 126 const struct nf_hook_state *state, 127 const char *msg) 128 { 129 nf_l4proto_log_invalid(skb, state, IPPROTO_ICMPV6, "%s", msg); 130 } 131 132 int nf_conntrack_icmpv6_error(struct nf_conn *tmpl, 133 struct sk_buff *skb, 134 unsigned int dataoff, 135 const struct nf_hook_state *state) 136 { 137 union nf_inet_addr outer_daddr; 138 const struct icmp6hdr *icmp6h; 139 struct icmp6hdr _ih; 140 int type; 141 142 icmp6h = skb_header_pointer(skb, dataoff, sizeof(_ih), &_ih); 143 if (icmp6h == NULL) { 144 icmpv6_error_log(skb, state, "short packet"); 145 return -NF_ACCEPT; 146 } 147 148 if (state->hook == NF_INET_PRE_ROUTING && 149 state->net->ct.sysctl_checksum && 150 nf_ip6_checksum(skb, state->hook, dataoff, IPPROTO_ICMPV6)) { 151 icmpv6_error_log(skb, state, "ICMPv6 checksum failed"); 152 return -NF_ACCEPT; 153 } 154 155 type = icmp6h->icmp6_type - 130; 156 if (type >= 0 && type < sizeof(noct_valid_new) && 157 noct_valid_new[type]) { 158 nf_ct_set(skb, NULL, IP_CT_UNTRACKED); 159 return NF_ACCEPT; 160 } 161 162 /* is not error message ? */ 163 if (icmp6h->icmp6_type >= 128) 164 return NF_ACCEPT; 165 166 memcpy(&outer_daddr.ip6, &ipv6_hdr(skb)->daddr, 167 sizeof(outer_daddr.ip6)); 168 dataoff += sizeof(*icmp6h); 169 return nf_conntrack_inet_error(tmpl, skb, dataoff, state, 170 IPPROTO_ICMPV6, &outer_daddr); 171 } 172 173 #if IS_ENABLED(CONFIG_NF_CT_NETLINK) 174 175 #include <linux/netfilter/nfnetlink.h> 176 #include <linux/netfilter/nfnetlink_conntrack.h> 177 static int icmpv6_tuple_to_nlattr(struct sk_buff *skb, 178 const struct nf_conntrack_tuple *t) 179 { 180 if (nla_put_be16(skb, CTA_PROTO_ICMPV6_ID, t->src.u.icmp.id) || 181 nla_put_u8(skb, CTA_PROTO_ICMPV6_TYPE, t->dst.u.icmp.type) || 182 nla_put_u8(skb, CTA_PROTO_ICMPV6_CODE, t->dst.u.icmp.code)) 183 goto nla_put_failure; 184 return 0; 185 186 nla_put_failure: 187 return -1; 188 } 189 190 static const struct nla_policy icmpv6_nla_policy[CTA_PROTO_MAX+1] = { 191 [CTA_PROTO_ICMPV6_TYPE] = { .type = NLA_U8 }, 192 [CTA_PROTO_ICMPV6_CODE] = { .type = NLA_U8 }, 193 [CTA_PROTO_ICMPV6_ID] = { .type = NLA_U16 }, 194 }; 195 196 static int icmpv6_nlattr_to_tuple(struct nlattr *tb[], 197 struct nf_conntrack_tuple *tuple, 198 u_int32_t flags) 199 { 200 if (flags & CTA_FILTER_FLAG(CTA_PROTO_ICMPV6_TYPE)) { 201 if (!tb[CTA_PROTO_ICMPV6_TYPE]) 202 return -EINVAL; 203 204 tuple->dst.u.icmp.type = nla_get_u8(tb[CTA_PROTO_ICMPV6_TYPE]); 205 if (tuple->dst.u.icmp.type < 128 || 206 tuple->dst.u.icmp.type - 128 >= sizeof(invmap) || 207 !invmap[tuple->dst.u.icmp.type - 128]) 208 return -EINVAL; 209 } 210 211 if (flags & CTA_FILTER_FLAG(CTA_PROTO_ICMPV6_CODE)) { 212 if (!tb[CTA_PROTO_ICMPV6_CODE]) 213 return -EINVAL; 214 215 tuple->dst.u.icmp.code = nla_get_u8(tb[CTA_PROTO_ICMPV6_CODE]); 216 } 217 218 if (flags & CTA_FILTER_FLAG(CTA_PROTO_ICMPV6_ID)) { 219 if (!tb[CTA_PROTO_ICMPV6_ID]) 220 return -EINVAL; 221 222 tuple->src.u.icmp.id = nla_get_be16(tb[CTA_PROTO_ICMPV6_ID]); 223 } 224 225 return 0; 226 } 227 228 static unsigned int icmpv6_nlattr_tuple_size(void) 229 { 230 static unsigned int size __read_mostly; 231 232 if (!size) 233 size = nla_policy_len(icmpv6_nla_policy, CTA_PROTO_MAX + 1); 234 235 return size; 236 } 237 #endif 238 239 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT 240 241 #include <linux/netfilter/nfnetlink.h> 242 #include <linux/netfilter/nfnetlink_cttimeout.h> 243 244 static int icmpv6_timeout_nlattr_to_obj(struct nlattr *tb[], 245 struct net *net, void *data) 246 { 247 unsigned int *timeout = data; 248 struct nf_icmp_net *in = nf_icmpv6_pernet(net); 249 250 if (!timeout) 251 timeout = icmpv6_get_timeouts(net); 252 if (tb[CTA_TIMEOUT_ICMPV6_TIMEOUT]) { 253 *timeout = 254 ntohl(nla_get_be32(tb[CTA_TIMEOUT_ICMPV6_TIMEOUT])) * HZ; 255 } else { 256 /* Set default ICMPv6 timeout. */ 257 *timeout = in->timeout; 258 } 259 return 0; 260 } 261 262 static int 263 icmpv6_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data) 264 { 265 const unsigned int *timeout = data; 266 267 if (nla_put_be32(skb, CTA_TIMEOUT_ICMPV6_TIMEOUT, htonl(*timeout / HZ))) 268 goto nla_put_failure; 269 return 0; 270 271 nla_put_failure: 272 return -ENOSPC; 273 } 274 275 static const struct nla_policy 276 icmpv6_timeout_nla_policy[CTA_TIMEOUT_ICMPV6_MAX+1] = { 277 [CTA_TIMEOUT_ICMPV6_TIMEOUT] = { .type = NLA_U32 }, 278 }; 279 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ 280 281 void nf_conntrack_icmpv6_init_net(struct net *net) 282 { 283 struct nf_icmp_net *in = nf_icmpv6_pernet(net); 284 285 in->timeout = nf_ct_icmpv6_timeout; 286 } 287 288 const struct nf_conntrack_l4proto nf_conntrack_l4proto_icmpv6 = 289 { 290 .l4proto = IPPROTO_ICMPV6, 291 #if IS_ENABLED(CONFIG_NF_CT_NETLINK) 292 .tuple_to_nlattr = icmpv6_tuple_to_nlattr, 293 .nlattr_tuple_size = icmpv6_nlattr_tuple_size, 294 .nlattr_to_tuple = icmpv6_nlattr_to_tuple, 295 .nla_policy = icmpv6_nla_policy, 296 #endif 297 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT 298 .ctnl_timeout = { 299 .nlattr_to_obj = icmpv6_timeout_nlattr_to_obj, 300 .obj_to_nlattr = icmpv6_timeout_obj_to_nlattr, 301 .nlattr_max = CTA_TIMEOUT_ICMP_MAX, 302 .obj_size = sizeof(unsigned int), 303 .nla_policy = icmpv6_timeout_nla_policy, 304 }, 305 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ 306 }; 307