// SPDX-License-Identifier: GPL-2.0-or-later /* * Internet Control Message Protocol (ICMPv6) * Linux INET6 implementation * * Authors: * Pedro Roque * * Based on net/ipv4/icmp.c * * RFC 1885 */ /* * Changes: * * Andi Kleen : exception handling * Andi Kleen add rate limits. never reply to a icmp. * add more length checks and other fixes. * yoshfuji : ensure to sent parameter problem for * fragments. * YOSHIFUJI Hideaki @USAGI: added sysctl for icmp rate limit. * Randy Dunlap and * YOSHIFUJI Hideaki @USAGI: Per-interface statistics support * Kazunori MIYAZAWA @USAGI: change output process to use ip6_append_data */ #define pr_fmt(fmt) "IPv6: " fmt #include #include #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_SYSCTL #include #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static DEFINE_PER_CPU(struct sock *, ipv6_icmp_sk); static int icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, u8 type, u8 code, int offset, __be32 info) { /* icmpv6_notify checks 8 bytes can be pulled, icmp6hdr is 8 bytes */ struct icmp6hdr *icmp6 = (struct icmp6hdr *) (skb->data + offset); struct net *net = dev_net(skb->dev); if (type == ICMPV6_PKT_TOOBIG) ip6_update_pmtu(skb, net, info, skb->dev->ifindex, 0, sock_net_uid(net, NULL)); else if (type == NDISC_REDIRECT) ip6_redirect(skb, net, skb->dev->ifindex, 0, sock_net_uid(net, NULL)); if (!(type & ICMPV6_INFOMSG_MASK)) if (icmp6->icmp6_type == ICMPV6_ECHO_REQUEST) ping_err(skb, offset, ntohl(info)); return 0; } static int icmpv6_rcv(struct sk_buff *skb); static const struct inet6_protocol icmpv6_protocol = { .handler = icmpv6_rcv, .err_handler = icmpv6_err, .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL, }; /* Called with BH disabled */ static struct sock *icmpv6_xmit_lock(struct net *net) { struct sock *sk; sk = this_cpu_read(ipv6_icmp_sk); if (unlikely(!spin_trylock(&sk->sk_lock.slock))) { /* This can happen if the output path (f.e. SIT or * ip6ip6 tunnel) signals dst_link_failure() for an * outgoing ICMP6 packet. */ return NULL; } sock_net_set(sk, net); return sk; } static void icmpv6_xmit_unlock(struct sock *sk) { sock_net_set(sk, &init_net); spin_unlock(&sk->sk_lock.slock); } /* * Figure out, may we reply to this packet with icmp error. * * We do not reply, if: * - it was icmp error message. * - it is truncated, so that it is known, that protocol is ICMPV6 * (i.e. in the middle of some exthdr) * * --ANK (980726) */ static bool is_ineligible(const struct sk_buff *skb) { int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data; int len = skb->len - ptr; __u8 nexthdr = ipv6_hdr(skb)->nexthdr; __be16 frag_off; if (len < 0) return true; ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, &frag_off); if (ptr < 0) return false; if (nexthdr == IPPROTO_ICMPV6) { u8 _type, *tp; tp = skb_header_pointer(skb, ptr+offsetof(struct icmp6hdr, icmp6_type), sizeof(_type), &_type); /* Based on RFC 8200, Section 4.5 Fragment Header, return * false if this is a fragment packet with no icmp header info. */ if (!tp && frag_off != 0) return false; else if (!tp || !(*tp & ICMPV6_INFOMSG_MASK)) return true; } return false; } static bool icmpv6_mask_allow(struct net *net, int type) { if (type > ICMPV6_MSG_MAX) return true; /* Limit if icmp type is set in ratemask. */ if (!test_bit(type, net->ipv6.sysctl.icmpv6_ratemask)) return true; return false; } static bool icmpv6_global_allow(struct net *net, int type, bool *apply_ratelimit) { if (icmpv6_mask_allow(net, type)) return true; if (icmp_global_allow(net)) { *apply_ratelimit = true; return true; } __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITGLOBAL); return false; } /* * Check the ICMP output rate limit */ static bool icmpv6_xrlim_allow(struct sock *sk, u8 type, struct flowi6 *fl6, bool apply_ratelimit) { struct net *net = sock_net(sk); struct dst_entry *dst; bool res = false; if (!apply_ratelimit) return true; /* * Look up the output route. * XXX: perhaps the expire for routing entries cloned by * this lookup should be more aggressive (not longer than timeout). */ dst = ip6_route_output(net, sk, fl6); if (dst->error) { IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES); } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) { res = true; } else { struct rt6_info *rt = dst_rt6_info(dst); int tmo = net->ipv6.sysctl.icmpv6_time; struct inet_peer *peer; /* Give more bandwidth to wider prefixes. */ if (rt->rt6i_dst.plen < 128) tmo >>= ((128 - rt->rt6i_dst.plen)>>5); rcu_read_lock(); peer = inet_getpeer_v6(net->ipv6.peers, &fl6->daddr); res = inet_peer_xrlim_allow(peer, tmo); rcu_read_unlock(); } if (!res) __ICMP6_INC_STATS(net, ip6_dst_idev(dst), ICMP6_MIB_RATELIMITHOST); else icmp_global_consume(net); dst_release(dst); return res; } static bool icmpv6_rt_has_prefsrc(struct sock *sk, u8 type, struct flowi6 *fl6) { struct net *net = sock_net(sk); struct dst_entry *dst; bool res = false; dst = ip6_route_output(net, sk, fl6); if (!dst->error) { struct rt6_info *rt = dst_rt6_info(dst); struct in6_addr prefsrc; rt6_get_prefsrc(rt, &prefsrc); res = !ipv6_addr_any(&prefsrc); } dst_release(dst); return res; } /* * an inline helper for the "simple" if statement below * checks if parameter problem report is caused by an * unrecognized IPv6 option that has the Option Type * highest-order two bits set to 10 */ static bool opt_unrec(struct sk_buff *skb, __u32 offset) { u8 _optval, *op; offset += skb_network_offset(skb); op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval); if (!op) return true; return (*op & 0xC0) == 0x80; } void icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6, struct icmp6hdr *thdr, int len) { struct sk_buff *skb; struct icmp6hdr *icmp6h; skb = skb_peek(&sk->sk_write_queue); if (!skb) return; icmp6h = icmp6_hdr(skb); memcpy(icmp6h, thdr, sizeof(struct icmp6hdr)); icmp6h->icmp6_cksum = 0; if (skb_queue_len(&sk->sk_write_queue) == 1) { skb->csum = csum_partial(icmp6h, sizeof(struct icmp6hdr), skb->csum); icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr, &fl6->daddr, len, fl6->flowi6_proto, skb->csum); } else { __wsum tmp_csum = 0; skb_queue_walk(&sk->sk_write_queue, skb) { tmp_csum = csum_add(tmp_csum, skb->csum); } tmp_csum = csum_partial(icmp6h, sizeof(struct icmp6hdr), tmp_csum); icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr, &fl6->daddr, len, fl6->flowi6_proto, tmp_csum); } ip6_push_pending_frames(sk); } struct icmpv6_msg { struct sk_buff *skb; int offset; uint8_t type; }; static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) { struct icmpv6_msg *msg = (struct icmpv6_msg *) from; struct sk_buff *org_skb = msg->skb; __wsum csum; csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset, to, len); skb->csum = csum_block_add(skb->csum, csum, odd); if (!(msg->type & ICMPV6_INFOMSG_MASK)) nf_ct_attach(skb, org_skb); return 0; } #if IS_ENABLED(CONFIG_IPV6_MIP6) static void mip6_addr_swap(struct sk_buff *skb, const struct inet6_skb_parm *opt) { struct ipv6hdr *iph = ipv6_hdr(skb); struct ipv6_destopt_hao *hao; int off; if (opt->dsthao) { off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO); if (likely(off >= 0)) { hao = (struct ipv6_destopt_hao *) (skb_network_header(skb) + off); swap(iph->saddr, hao->addr); } } } #else static inline void mip6_addr_swap(struct sk_buff *skb, const struct inet6_skb_parm *opt) {} #endif static struct dst_entry *icmpv6_route_lookup(struct net *net, struct sk_buff *skb, struct sock *sk, struct flowi6 *fl6) { struct dst_entry *dst, *dst2; struct flowi6 fl2; int err; err = ip6_dst_lookup(net, sk, &dst, fl6); if (err) return ERR_PTR(err); /* * We won't send icmp if the destination is known * anycast unless we need to treat anycast as unicast. */ if (!READ_ONCE(net->ipv6.sysctl.icmpv6_error_anycast_as_unicast) && ipv6_anycast_destination(dst, &fl6->daddr)) { net_dbg_ratelimited("icmp6_send: acast source\n"); dst_release(dst); return ERR_PTR(-EINVAL); } /* No need to clone since we're just using its address. */ dst2 = dst; dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0); if (!IS_ERR(dst)) { if (dst != dst2) return dst; } else { if (PTR_ERR(dst) == -EPERM) dst = NULL; else return dst; } err = xfrm_decode_session_reverse(net, skb, flowi6_to_flowi(&fl2), AF_INET6); if (err) goto relookup_failed; err = ip6_dst_lookup(net, sk, &dst2, &fl2); if (err) goto relookup_failed; dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP); if (!IS_ERR(dst2)) { dst_release(dst); dst = dst2; } else { err = PTR_ERR(dst2); if (err == -EPERM) { dst_release(dst); return dst2; } else goto relookup_failed; } relookup_failed: if (dst) return dst; return ERR_PTR(err); } static struct net_device *icmp6_dev(const struct sk_buff *skb) { struct net_device *dev = skb->dev; /* for local traffic to local address, skb dev is the loopback * device. Check if there is a dst attached to the skb and if so * get the real device index. Same is needed for replies to a link * local address on a device enslaved to an L3 master device */ if (unlikely(dev->ifindex == LOOPBACK_IFINDEX || netif_is_l3_master(skb->dev))) { const struct rt6_info *rt6 = skb_rt6_info(skb); /* The destination could be an external IP in Ext Hdr (SRv6, RPL, etc.), * and ip6_null_entry could be set to skb if no route is found. */ if (rt6 && rt6->rt6i_idev) dev = rt6->rt6i_idev->dev; } return dev; } static int icmp6_iif(const struct sk_buff *skb) { return icmp6_dev(skb)->ifindex; } /* * Send an ICMP message in response to a packet in error */ void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, const struct in6_addr *force_saddr, const struct inet6_skb_parm *parm) { struct inet6_dev *idev = NULL; struct ipv6hdr *hdr = ipv6_hdr(skb); struct sock *sk; struct net *net; struct ipv6_pinfo *np; const struct in6_addr *saddr = NULL; bool apply_ratelimit = false; struct dst_entry *dst; struct icmp6hdr tmp_hdr; struct flowi6 fl6; struct icmpv6_msg msg; struct ipcm6_cookie ipc6; int iif = 0; int addr_type = 0; int len; u32 mark; if ((u8 *)hdr < skb->head || (skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb)) return; if (!skb->dev) return; net = dev_net(skb->dev); mark = IP6_REPLY_MARK(net, skb->mark); /* * Make sure we respect the rules * i.e. RFC 1885 2.4(e) * Rule (e.1) is enforced by not using icmp6_send * in any code that processes icmp errors. */ addr_type = ipv6_addr_type(&hdr->daddr); if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0) || ipv6_chk_acast_addr_src(net, skb->dev, &hdr->daddr)) saddr = &hdr->daddr; /* * Dest addr check */ if (addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST) { if (type != ICMPV6_PKT_TOOBIG && !(type == ICMPV6_PARAMPROB && code == ICMPV6_UNK_OPTION && (opt_unrec(skb, info)))) return; saddr = NULL; } addr_type = ipv6_addr_type(&hdr->saddr); /* * Source addr check */ if (__ipv6_addr_needs_scope_id(addr_type)) { iif = icmp6_iif(skb); } else { /* * The source device is used for looking up which routing table * to use for sending an ICMP error. */ iif = l3mdev_master_ifindex(skb->dev); } /* * Must not send error if the source does not uniquely * identify a single node (RFC2463 Section 2.4). * We check unspecified / multicast addresses here, * and anycast addresses will be checked later. */ if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) { net_dbg_ratelimited("icmp6_send: addr_any/mcast source [%pI6c > %pI6c]\n", &hdr->saddr, &hdr->daddr); return; } /* * Never answer to a ICMP packet. */ if (is_ineligible(skb)) { net_dbg_ratelimited("icmp6_send: no reply to icmp error [%pI6c > %pI6c]\n", &hdr->saddr, &hdr->daddr); return; } /* Needed by both icmpv6_global_allow and icmpv6_xmit_lock */ local_bh_disable(); /* Check global sysctl_icmp_msgs_per_sec ratelimit */ if (!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, type, &apply_ratelimit)) goto out_bh_enable; mip6_addr_swap(skb, parm); sk = icmpv6_xmit_lock(net); if (!sk) goto out_bh_enable; memset(&fl6, 0, sizeof(fl6)); fl6.flowi6_proto = IPPROTO_ICMPV6; fl6.daddr = hdr->saddr; if (force_saddr) saddr = force_saddr; if (saddr) { fl6.saddr = *saddr; } else if (!icmpv6_rt_has_prefsrc(sk, type, &fl6)) { /* select a more meaningful saddr from input if */ struct net_device *in_netdev; in_netdev = dev_get_by_index(net, parm->iif); if (in_netdev) { ipv6_dev_get_saddr(net, in_netdev, &fl6.daddr, inet6_sk(sk)->srcprefs, &fl6.saddr); dev_put(in_netdev); } } fl6.flowi6_mark = mark; fl6.flowi6_oif = iif; fl6.fl6_icmp_type = type; fl6.fl6_icmp_code = code; fl6.flowi6_uid = sock_net_uid(net, NULL); fl6.mp_hash = rt6_multipath_hash(net, &fl6, skb, NULL); security_skb_classify_flow(skb, flowi6_to_flowi_common(&fl6)); np = inet6_sk(sk); if (!icmpv6_xrlim_allow(sk, type, &fl6, apply_ratelimit)) goto out; tmp_hdr.icmp6_type = type; tmp_hdr.icmp6_code = code; tmp_hdr.icmp6_cksum = 0; tmp_hdr.icmp6_pointer = htonl(info); if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) fl6.flowi6_oif = READ_ONCE(np->mcast_oif); else if (!fl6.flowi6_oif) fl6.flowi6_oif = READ_ONCE(np->ucast_oif); ipcm6_init_sk(&ipc6, sk); ipc6.sockc.mark = mark; fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel); dst = icmpv6_route_lookup(net, skb, sk, &fl6); if (IS_ERR(dst)) goto out; ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); msg.skb = skb; msg.offset = skb_network_offset(skb); msg.type = type; len = skb->len - msg.offset; len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(struct icmp6hdr)); if (len < 0) { net_dbg_ratelimited("icmp: len problem [%pI6c > %pI6c]\n", &hdr->saddr, &hdr->daddr); goto out_dst_release; } rcu_read_lock(); idev = __in6_dev_get(skb->dev); if (ip6_append_data(sk, icmpv6_getfrag, &msg, len + sizeof(struct icmp6hdr), sizeof(struct icmp6hdr), &ipc6, &fl6, dst_rt6_info(dst), MSG_DONTWAIT)) { ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS); ip6_flush_pending_frames(sk); } else { icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, len + sizeof(struct icmp6hdr)); } rcu_read_unlock(); out_dst_release: dst_release(dst); out: icmpv6_xmit_unlock(sk); out_bh_enable: local_bh_enable(); } EXPORT_SYMBOL(icmp6_send); /* Slightly more convenient version of icmp6_send with drop reasons. */ void icmpv6_param_prob_reason(struct sk_buff *skb, u8 code, int pos, enum skb_drop_reason reason) { icmp6_send(skb, ICMPV6_PARAMPROB, code, pos, NULL, IP6CB(skb)); kfree_skb_reason(skb, reason); } /* Generate icmpv6 with type/code ICMPV6_DEST_UNREACH/ICMPV6_ADDR_UNREACH * if sufficient data bytes are available * @nhs is the size of the tunnel header(s) : * Either an IPv4 header for SIT encap * an IPv4 header + GRE header for GRE encap */ int ip6_err_gen_icmpv6_unreach(struct sk_buff *skb, int nhs, int type, unsigned int data_len) { struct in6_addr temp_saddr; struct rt6_info *rt; struct sk_buff *skb2; u32 info = 0; if (!pskb_may_pull(skb, nhs + sizeof(struct ipv6hdr) + 8)) return 1; /* RFC 4884 (partial) support for ICMP extensions */ if (data_len < 128 || (data_len & 7) || skb->len < data_len) data_len = 0; skb2 = data_len ? skb_copy(skb, GFP_ATOMIC) : skb_clone(skb, GFP_ATOMIC); if (!skb2) return 1; skb_dst_drop(skb2); skb_pull(skb2, nhs); skb_reset_network_header(skb2); rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr, NULL, 0, skb, 0); if (rt && rt->dst.dev) skb2->dev = rt->dst.dev; ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr, &temp_saddr); if (data_len) { /* RFC 4884 (partial) support : * insert 0 padding at the end, before the extensions */ __skb_push(skb2, nhs); skb_reset_network_header(skb2); memmove(skb2->data, skb2->data + nhs, data_len - nhs); memset(skb2->data + data_len - nhs, 0, nhs); /* RFC 4884 4.5 : Length is measured in 64-bit words, * and stored in reserved[0] */ info = (data_len/8) << 24; } if (type == ICMP_TIME_EXCEEDED) icmp6_send(skb2, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, info, &temp_saddr, IP6CB(skb2)); else icmp6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, info, &temp_saddr, IP6CB(skb2)); if (rt) ip6_rt_put(rt); kfree_skb(skb2); return 0; } EXPORT_SYMBOL(ip6_err_gen_icmpv6_unreach); static enum skb_drop_reason icmpv6_echo_reply(struct sk_buff *skb) { struct net *net = dev_net(skb->dev); struct sock *sk; struct inet6_dev *idev; struct ipv6_pinfo *np; const struct in6_addr *saddr = NULL; struct icmp6hdr *icmph = icmp6_hdr(skb); bool apply_ratelimit = false; struct icmp6hdr tmp_hdr; struct flowi6 fl6; struct icmpv6_msg msg; struct dst_entry *dst; struct ipcm6_cookie ipc6; u32 mark = IP6_REPLY_MARK(net, skb->mark); SKB_DR(reason); bool acast; u8 type; if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) && net->ipv6.sysctl.icmpv6_echo_ignore_multicast) return reason; saddr = &ipv6_hdr(skb)->daddr; acast = ipv6_anycast_destination(skb_dst(skb), saddr); if (acast && net->ipv6.sysctl.icmpv6_echo_ignore_anycast) return reason; if (!ipv6_unicast_destination(skb) && !(net->ipv6.sysctl.anycast_src_echo_reply && acast)) saddr = NULL; if (icmph->icmp6_type == ICMPV6_EXT_ECHO_REQUEST) type = ICMPV6_EXT_ECHO_REPLY; else type = ICMPV6_ECHO_REPLY; memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr)); tmp_hdr.icmp6_type = type; memset(&fl6, 0, sizeof(fl6)); if (net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_ICMPV6_ECHO_REPLIES) fl6.flowlabel = ip6_flowlabel(ipv6_hdr(skb)); fl6.flowi6_proto = IPPROTO_ICMPV6; fl6.daddr = ipv6_hdr(skb)->saddr; if (saddr) fl6.saddr = *saddr; fl6.flowi6_oif = icmp6_iif(skb); fl6.fl6_icmp_type = type; fl6.flowi6_mark = mark; fl6.flowi6_uid = sock_net_uid(net, NULL); security_skb_classify_flow(skb, flowi6_to_flowi_common(&fl6)); local_bh_disable(); sk = icmpv6_xmit_lock(net); if (!sk) goto out_bh_enable; np = inet6_sk(sk); if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) fl6.flowi6_oif = READ_ONCE(np->mcast_oif); else if (!fl6.flowi6_oif) fl6.flowi6_oif = READ_ONCE(np->ucast_oif); if (ip6_dst_lookup(net, sk, &dst, &fl6)) goto out; dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0); if (IS_ERR(dst)) goto out; /* Check the ratelimit */ if ((!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, ICMPV6_ECHO_REPLY, &apply_ratelimit)) || !icmpv6_xrlim_allow(sk, ICMPV6_ECHO_REPLY, &fl6, apply_ratelimit)) goto out_dst_release; idev = __in6_dev_get(skb->dev); msg.skb = skb; msg.offset = 0; msg.type = type; ipcm6_init_sk(&ipc6, sk); ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); ipc6.tclass = ipv6_get_dsfield(ipv6_hdr(skb)); ipc6.sockc.mark = mark; if (icmph->icmp6_type == ICMPV6_EXT_ECHO_REQUEST) if (!icmp_build_probe(skb, (struct icmphdr *)&tmp_hdr)) goto out_dst_release; if (ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr), sizeof(struct icmp6hdr), &ipc6, &fl6, dst_rt6_info(dst), MSG_DONTWAIT)) { __ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS); ip6_flush_pending_frames(sk); } else { icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, skb->len + sizeof(struct icmp6hdr)); reason = SKB_CONSUMED; } out_dst_release: dst_release(dst); out: icmpv6_xmit_unlock(sk); out_bh_enable: local_bh_enable(); return reason; } enum skb_drop_reason icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info) { struct inet6_skb_parm *opt = IP6CB(skb); struct net *net = dev_net(skb->dev); const struct inet6_protocol *ipprot; enum skb_drop_reason reason; int inner_offset; __be16 frag_off; u8 nexthdr; reason = pskb_may_pull_reason(skb, sizeof(struct ipv6hdr)); if (reason != SKB_NOT_DROPPED_YET) goto out; seg6_icmp_srh(skb, opt); nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr; if (ipv6_ext_hdr(nexthdr)) { /* now skip over extension headers */ inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr, &frag_off); if (inner_offset < 0) { SKB_DR_SET(reason, IPV6_BAD_EXTHDR); goto out; } } else { inner_offset = sizeof(struct ipv6hdr); } /* Checkin header including 8 bytes of inner protocol header. */ reason = pskb_may_pull_reason(skb, inner_offset + 8); if (reason != SKB_NOT_DROPPED_YET) goto out; /* BUGGG_FUTURE: we should try to parse exthdrs in this packet. Without this we will not able f.e. to make source routed pmtu discovery. Corresponding argument (opt) to notifiers is already added. --ANK (980726) */ ipprot = rcu_dereference(inet6_protos[nexthdr]); if (ipprot && ipprot->err_handler) ipprot->err_handler(skb, opt, type, code, inner_offset, info); raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info); return SKB_CONSUMED; out: __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS); return reason; } /* * Handle icmp messages */ static int icmpv6_rcv(struct sk_buff *skb) { enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED; struct net *net = dev_net(skb->dev); struct net_device *dev = icmp6_dev(skb); struct inet6_dev *idev = __in6_dev_get(dev); const struct in6_addr *saddr, *daddr; struct icmp6hdr *hdr; u8 type; if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { struct sec_path *sp = skb_sec_path(skb); int nh; if (!(sp && sp->xvec[sp->len - 1]->props.flags & XFRM_STATE_ICMP)) { reason = SKB_DROP_REASON_XFRM_POLICY; goto drop_no_count; } if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr))) goto drop_no_count; nh = skb_network_offset(skb); skb_set_network_header(skb, sizeof(*hdr)); if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb)) { reason = SKB_DROP_REASON_XFRM_POLICY; goto drop_no_count; } skb_set_network_header(skb, nh); } __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INMSGS); saddr = &ipv6_hdr(skb)->saddr; daddr = &ipv6_hdr(skb)->daddr; if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) { net_dbg_ratelimited("ICMPv6 checksum failed [%pI6c > %pI6c]\n", saddr, daddr); goto csum_error; } if (!pskb_pull(skb, sizeof(*hdr))) goto discard_it; hdr = icmp6_hdr(skb); type = hdr->icmp6_type; ICMP6MSGIN_INC_STATS(dev_net(dev), idev, type); switch (type) { case ICMPV6_ECHO_REQUEST: if (!net->ipv6.sysctl.icmpv6_echo_ignore_all) reason = icmpv6_echo_reply(skb); break; case ICMPV6_EXT_ECHO_REQUEST: if (!net->ipv6.sysctl.icmpv6_echo_ignore_all && READ_ONCE(net->ipv4.sysctl_icmp_echo_enable_probe)) reason = icmpv6_echo_reply(skb); break; case ICMPV6_ECHO_REPLY: reason = ping_rcv(skb); break; case ICMPV6_EXT_ECHO_REPLY: reason = ping_rcv(skb); break; case ICMPV6_PKT_TOOBIG: /* BUGGG_FUTURE: if packet contains rthdr, we cannot update standard destination cache. Seems, only "advanced" destination cache will allow to solve this problem --ANK (980726) */ if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) goto discard_it; hdr = icmp6_hdr(skb); /* to notify */ fallthrough; case ICMPV6_DEST_UNREACH: case ICMPV6_TIME_EXCEED: case ICMPV6_PARAMPROB: reason = icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); break; case NDISC_ROUTER_SOLICITATION: case NDISC_ROUTER_ADVERTISEMENT: case NDISC_NEIGHBOUR_SOLICITATION: case NDISC_NEIGHBOUR_ADVERTISEMENT: case NDISC_REDIRECT: reason = ndisc_rcv(skb); break; case ICMPV6_MGM_QUERY: igmp6_event_query(skb); return 0; case ICMPV6_MGM_REPORT: igmp6_event_report(skb); return 0; case ICMPV6_MGM_REDUCTION: case ICMPV6_NI_QUERY: case ICMPV6_NI_REPLY: case ICMPV6_MLD2_REPORT: case ICMPV6_DHAAD_REQUEST: case ICMPV6_DHAAD_REPLY: case ICMPV6_MOBILE_PREFIX_SOL: case ICMPV6_MOBILE_PREFIX_ADV: break; default: /* informational */ if (type & ICMPV6_INFOMSG_MASK) break; net_dbg_ratelimited("icmpv6: msg of unknown type [%pI6c > %pI6c]\n", saddr, daddr); /* * error of unknown type. * must pass to upper level */ reason = icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); } /* until the v6 path can be better sorted assume failure and * preserve the status quo behaviour for the rest of the paths to here */ if (reason) kfree_skb_reason(skb, reason); else consume_skb(skb); return 0; csum_error: reason = SKB_DROP_REASON_ICMP_CSUM; __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS); discard_it: __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INERRORS); drop_no_count: kfree_skb_reason(skb, reason); return 0; } void icmpv6_flow_init(const struct sock *sk, struct flowi6 *fl6, u8 type, const struct in6_addr *saddr, const struct in6_addr *daddr, int oif) { memset(fl6, 0, sizeof(*fl6)); fl6->saddr = *saddr; fl6->daddr = *daddr; fl6->flowi6_proto = IPPROTO_ICMPV6; fl6->fl6_icmp_type = type; fl6->fl6_icmp_code = 0; fl6->flowi6_oif = oif; security_sk_classify_flow(sk, flowi6_to_flowi_common(fl6)); } int __init icmpv6_init(void) { struct sock *sk; int err, i; for_each_possible_cpu(i) { err = inet_ctl_sock_create(&sk, PF_INET6, SOCK_RAW, IPPROTO_ICMPV6, &init_net); if (err < 0) { pr_err("Failed to initialize the ICMP6 control socket (err %d)\n", err); return err; } per_cpu(ipv6_icmp_sk, i) = sk; /* Enough space for 2 64K ICMP packets, including * sk_buff struct overhead. */ sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024); } err = -EAGAIN; if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0) goto fail; err = inet6_register_icmp_sender(icmp6_send); if (err) goto sender_reg_err; return 0; sender_reg_err: inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); fail: pr_err("Failed to register ICMP6 protocol\n"); return err; } void icmpv6_cleanup(void) { inet6_unregister_icmp_sender(icmp6_send); inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); } static const struct icmp6_err { int err; int fatal; } tab_unreach[] = { { /* NOROUTE */ .err = ENETUNREACH, .fatal = 0, }, { /* ADM_PROHIBITED */ .err = EACCES, .fatal = 1, }, { /* Was NOT_NEIGHBOUR, now reserved */ .err = EHOSTUNREACH, .fatal = 0, }, { /* ADDR_UNREACH */ .err = EHOSTUNREACH, .fatal = 0, }, { /* PORT_UNREACH */ .err = ECONNREFUSED, .fatal = 1, }, { /* POLICY_FAIL */ .err = EACCES, .fatal = 1, }, { /* REJECT_ROUTE */ .err = EACCES, .fatal = 1, }, }; int icmpv6_err_convert(u8 type, u8 code, int *err) { int fatal = 0; *err = EPROTO; switch (type) { case ICMPV6_DEST_UNREACH: fatal = 1; if (code < ARRAY_SIZE(tab_unreach)) { *err = tab_unreach[code].err; fatal = tab_unreach[code].fatal; } break; case ICMPV6_PKT_TOOBIG: *err = EMSGSIZE; break; case ICMPV6_PARAMPROB: *err = EPROTO; fatal = 1; break; case ICMPV6_TIME_EXCEED: *err = EHOSTUNREACH; break; } return fatal; } EXPORT_SYMBOL(icmpv6_err_convert); #ifdef CONFIG_SYSCTL static struct ctl_table ipv6_icmp_table_template[] = { { .procname = "ratelimit", .data = &init_net.ipv6.sysctl.icmpv6_time, .maxlen = sizeof(int), .mode = 0644, .proc_handler = proc_dointvec_ms_jiffies, }, { .procname = "echo_ignore_all", .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_all, .maxlen = sizeof(u8), .mode = 0644, .proc_handler = proc_dou8vec_minmax, }, { .procname = "echo_ignore_multicast", .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_multicast, .maxlen = sizeof(u8), .mode = 0644, .proc_handler = proc_dou8vec_minmax, }, { .procname = "echo_ignore_anycast", .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_anycast, .maxlen = sizeof(u8), .mode = 0644, .proc_handler = proc_dou8vec_minmax, }, { .procname = "ratemask", .data = &init_net.ipv6.sysctl.icmpv6_ratemask_ptr, .maxlen = ICMPV6_MSG_MAX + 1, .mode = 0644, .proc_handler = proc_do_large_bitmap, }, { .procname = "error_anycast_as_unicast", .data = &init_net.ipv6.sysctl.icmpv6_error_anycast_as_unicast, .maxlen = sizeof(u8), .mode = 0644, .proc_handler = proc_dou8vec_minmax, .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_ONE, }, }; struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net) { struct ctl_table *table; table = kmemdup(ipv6_icmp_table_template, sizeof(ipv6_icmp_table_template), GFP_KERNEL); if (table) { table[0].data = &net->ipv6.sysctl.icmpv6_time; table[1].data = &net->ipv6.sysctl.icmpv6_echo_ignore_all; table[2].data = &net->ipv6.sysctl.icmpv6_echo_ignore_multicast; table[3].data = &net->ipv6.sysctl.icmpv6_echo_ignore_anycast; table[4].data = &net->ipv6.sysctl.icmpv6_ratemask_ptr; table[5].data = &net->ipv6.sysctl.icmpv6_error_anycast_as_unicast; } return table; } size_t ipv6_icmp_sysctl_table_size(void) { return ARRAY_SIZE(ipv6_icmp_table_template); } #endif