diff options
Diffstat (limited to 'net/ipv6/icmp.c')
| -rw-r--r-- | net/ipv6/icmp.c | 1220 |
1 files changed, 1220 insertions, 0 deletions
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c new file mode 100644 index 000000000..d01165bb6 --- /dev/null +++ b/net/ipv6/icmp.c @@ -0,0 +1,1220 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Internet Control Message Protocol (ICMPv6) + * Linux INET6 implementation + * + * Authors: + * Pedro Roque <roque@di.fc.ul.pt> + * + * 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 <linux/module.h> +#include <linux/errno.h> +#include <linux/types.h> +#include <linux/socket.h> +#include <linux/in.h> +#include <linux/kernel.h> +#include <linux/sockios.h> +#include <linux/net.h> +#include <linux/skbuff.h> +#include <linux/init.h> +#include <linux/netfilter.h> +#include <linux/slab.h> + +#ifdef CONFIG_SYSCTL +#include <linux/sysctl.h> +#endif + +#include <linux/inet.h> +#include <linux/netdevice.h> +#include <linux/icmpv6.h> + +#include <net/ip.h> +#include <net/sock.h> + +#include <net/ipv6.h> +#include <net/ip6_checksum.h> +#include <net/ping.h> +#include <net/protocol.h> +#include <net/raw.h> +#include <net/rawv6.h> +#include <net/transp_v6.h> +#include <net/ip6_route.h> +#include <net/addrconf.h> +#include <net/icmp.h> +#include <net/xfrm.h> +#include <net/inet_common.h> +#include <net/dsfield.h> +#include <net/l3mdev.h> + +#include <linux/uaccess.h> + +/* + * The ICMP socket(s). This is the most convenient way to flow control + * our ICMP output as well as maintain a clean interface throughout + * all layers. All Socketless IP sends will soon be gone. + * + * On SMP we have one ICMP socket per-cpu. + */ +static struct sock *icmpv6_sk(struct net *net) +{ + return this_cpu_read(*net->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 __inline__ struct sock *icmpv6_xmit_lock(struct net *net) +{ + struct sock *sk; + + sk = icmpv6_sk(net); + 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; + } + return sk; +} + +static __inline__ void icmpv6_xmit_unlock(struct sock *sk) +{ + 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) +{ + if (icmpv6_mask_allow(net, type)) + return true; + + if (icmp_global_allow()) + return true; + + return false; +} + +/* + * Check the ICMP output rate limit + */ +static bool icmpv6_xrlim_allow(struct sock *sk, u8 type, + struct flowi6 *fl6) +{ + struct net *net = sock_net(sk); + struct dst_entry *dst; + bool res = false; + + if (icmpv6_mask_allow(net, type)) + 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 = (struct 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); + + peer = inet_getpeer_v6(net->ipv6.peers, &fl6->daddr, 1); + res = inet_peer_xrlim_allow(peer, tmo); + if (peer) + inet_putpeer(peer); + } + 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 = (struct 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; + struct in6_addr tmp; + 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); + tmp = iph->saddr; + iph->saddr = hao->addr; + hao->addr = tmp; + } + } +} +#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. + */ + if (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(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; + 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 icmp_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)) + 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)) + 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 = np->mcast_oif; + else if (!fl6.flowi6_oif) + fl6.flowi6_oif = np->ucast_oif; + + ipcm6_init_sk(&ipc6, np); + 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, (struct 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. + */ +void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos) +{ + icmp6_send(skb, ICMPV6_PARAMPROB, code, pos, NULL, IP6CB(skb)); + kfree_skb(skb); +} + +/* 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 void 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); + 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); + bool acast; + + if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) && + net->ipv6.sysctl.icmpv6_echo_ignore_multicast) + return; + + saddr = &ipv6_hdr(skb)->daddr; + + acast = ipv6_anycast_destination(skb_dst(skb), saddr); + if (acast && net->ipv6.sysctl.icmpv6_echo_ignore_anycast) + return; + + if (!ipv6_unicast_destination(skb) && + !(net->ipv6.sysctl.anycast_src_echo_reply && acast)) + saddr = NULL; + + memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr)); + tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY; + + 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 = ICMPV6_ECHO_REPLY; + 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 = np->mcast_oif; + else if (!fl6.flowi6_oif) + fl6.flowi6_oif = 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)) || + !icmpv6_xrlim_allow(sk, ICMPV6_ECHO_REPLY, &fl6)) + goto out_dst_release; + + idev = __in6_dev_get(skb->dev); + + msg.skb = skb; + msg.offset = 0; + msg.type = ICMPV6_ECHO_REPLY; + + ipcm6_init_sk(&ipc6, np); + ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); + ipc6.tclass = ipv6_get_dsfield(ipv6_hdr(skb)); + ipc6.sockc.mark = mark; + + if (ip6_append_data(sk, icmpv6_getfrag, &msg, + skb->len + sizeof(struct icmp6hdr), + sizeof(struct icmp6hdr), &ipc6, &fl6, + (struct 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)); + } +out_dst_release: + dst_release(dst); +out: + icmpv6_xmit_unlock(sk); +out_bh_enable: + local_bh_enable(); +} + +void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info) +{ + const struct inet6_protocol *ipprot; + int inner_offset; + __be16 frag_off; + u8 nexthdr; + struct net *net = dev_net(skb->dev); + + if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) + goto out; + + 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) + goto out; + } else { + inner_offset = sizeof(struct ipv6hdr); + } + + /* Checkin header including 8 bytes of inner protocol header. */ + if (!pskb_may_pull(skb, inner_offset+8)) + 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, NULL, type, code, inner_offset, info); + + raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info); + return; + +out: + __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS); +} + +/* + * Handle icmp messages + */ + +static int icmpv6_rcv(struct sk_buff *skb) +{ + 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; + bool success = false; + + 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)) + 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)) + 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) + icmpv6_echo_reply(skb); + break; + + case ICMPV6_ECHO_REPLY: + success = 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: + 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: + ndisc_rcv(skb); + break; + + case ICMPV6_MGM_QUERY: + igmp6_event_query(skb); + break; + + case ICMPV6_MGM_REPORT: + igmp6_event_report(skb); + break; + + 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 + */ + + 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 (success) + consume_skb(skb); + else + kfree_skb(skb); + + return 0; + +csum_error: + __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(skb); + return 0; +} + +void icmpv6_flow_init(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)); +} + +static void __net_exit icmpv6_sk_exit(struct net *net) +{ + int i; + + for_each_possible_cpu(i) + inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv6.icmp_sk, i)); + free_percpu(net->ipv6.icmp_sk); +} + +static int __net_init icmpv6_sk_init(struct net *net) +{ + struct sock *sk; + int err, i; + + net->ipv6.icmp_sk = alloc_percpu(struct sock *); + if (!net->ipv6.icmp_sk) + return -ENOMEM; + + for_each_possible_cpu(i) { + err = inet_ctl_sock_create(&sk, PF_INET6, + SOCK_RAW, IPPROTO_ICMPV6, net); + if (err < 0) { + pr_err("Failed to initialize the ICMP6 control socket (err %d)\n", + err); + goto fail; + } + + *per_cpu_ptr(net->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); + } + return 0; + + fail: + icmpv6_sk_exit(net); + return err; +} + +static struct pernet_operations icmpv6_sk_ops = { + .init = icmpv6_sk_init, + .exit = icmpv6_sk_exit, +}; + +int __init icmpv6_init(void) +{ + int err; + + err = register_pernet_subsys(&icmpv6_sk_ops); + if (err < 0) + return err; + + 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"); + unregister_pernet_subsys(&icmpv6_sk_ops); + return err; +} + +void icmpv6_cleanup(void) +{ + inet6_unregister_icmp_sender(icmp6_send); + unregister_pernet_subsys(&icmpv6_sk_ops); + 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(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { + .procname = "echo_ignore_multicast", + .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_multicast, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { + .procname = "echo_ignore_anycast", + .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_anycast, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { + .procname = "ratemask", + .data = &init_net.ipv6.sysctl.icmpv6_ratemask_ptr, + .maxlen = ICMPV6_MSG_MAX + 1, + .mode = 0644, + .proc_handler = proc_do_large_bitmap, + }, + { }, +}; + +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; + } + return table; +} +#endif |