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-rw-r--r--net/ipv6/icmp.c1208
1 files changed, 1208 insertions, 0 deletions
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
new file mode 100644
index 000000000..e2af7ab99
--- /dev/null
+++ b/net/ipv6/icmp.c
@@ -0,0 +1,1208 @@
+// 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/seg6.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>
+
+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)
+{
+ 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 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 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;
+ u8 type;
+
+ 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;
+
+ 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 = 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 = type;
+
+ 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 (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,
+ (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)
+{
+ struct inet6_skb_parm *opt = IP6CB(skb);
+ 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;
+
+ 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)
+ 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, opt, 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)
+{
+ 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)
+ 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))
+ 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:
+ 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);
+ 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
+ */
+
+ 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(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,
+ },
+ { },
+};
+
+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
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-17 04:50:20 +0000