From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- net/ipv6/ip6_input.c | 593 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 593 insertions(+) create mode 100644 net/ipv6/ip6_input.c (limited to 'net/ipv6/ip6_input.c') diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c new file mode 100644 index 000000000..b83788145 --- /dev/null +++ b/net/ipv6/ip6_input.c @@ -0,0 +1,593 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * IPv6 input + * Linux INET6 implementation + * + * Authors: + * Pedro Roque + * Ian P. Morris + * + * Based in linux/net/ipv4/ip_input.c + */ +/* Changes + * + * Mitsuru KANDA @USAGI and + * YOSHIFUJI Hideaki @USAGI: Remove ipv6_parse_exthdrs(). + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static void ip6_rcv_finish_core(struct net *net, struct sock *sk, + struct sk_buff *skb) +{ + if (READ_ONCE(net->ipv4.sysctl_ip_early_demux) && + !skb_dst(skb) && !skb->sk) { + switch (ipv6_hdr(skb)->nexthdr) { + case IPPROTO_TCP: + if (READ_ONCE(net->ipv4.sysctl_tcp_early_demux)) + tcp_v6_early_demux(skb); + break; + case IPPROTO_UDP: + if (READ_ONCE(net->ipv4.sysctl_udp_early_demux)) + udp_v6_early_demux(skb); + break; + } + } + + if (!skb_valid_dst(skb)) + ip6_route_input(skb); +} + +int ip6_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb) +{ + /* if ingress device is enslaved to an L3 master device pass the + * skb to its handler for processing + */ + skb = l3mdev_ip6_rcv(skb); + if (!skb) + return NET_RX_SUCCESS; + ip6_rcv_finish_core(net, sk, skb); + + return dst_input(skb); +} + +static void ip6_sublist_rcv_finish(struct list_head *head) +{ + struct sk_buff *skb, *next; + + list_for_each_entry_safe(skb, next, head, list) { + skb_list_del_init(skb); + dst_input(skb); + } +} + +static bool ip6_can_use_hint(const struct sk_buff *skb, + const struct sk_buff *hint) +{ + return hint && !skb_dst(skb) && + ipv6_addr_equal(&ipv6_hdr(hint)->daddr, &ipv6_hdr(skb)->daddr); +} + +static struct sk_buff *ip6_extract_route_hint(const struct net *net, + struct sk_buff *skb) +{ + if (fib6_routes_require_src(net) || fib6_has_custom_rules(net) || + IP6CB(skb)->flags & IP6SKB_MULTIPATH) + return NULL; + + return skb; +} + +static void ip6_list_rcv_finish(struct net *net, struct sock *sk, + struct list_head *head) +{ + struct sk_buff *skb, *next, *hint = NULL; + struct dst_entry *curr_dst = NULL; + struct list_head sublist; + + INIT_LIST_HEAD(&sublist); + list_for_each_entry_safe(skb, next, head, list) { + struct dst_entry *dst; + + skb_list_del_init(skb); + /* if ingress device is enslaved to an L3 master device pass the + * skb to its handler for processing + */ + skb = l3mdev_ip6_rcv(skb); + if (!skb) + continue; + + if (ip6_can_use_hint(skb, hint)) + skb_dst_copy(skb, hint); + else + ip6_rcv_finish_core(net, sk, skb); + dst = skb_dst(skb); + if (curr_dst != dst) { + hint = ip6_extract_route_hint(net, skb); + + /* dispatch old sublist */ + if (!list_empty(&sublist)) + ip6_sublist_rcv_finish(&sublist); + /* start new sublist */ + INIT_LIST_HEAD(&sublist); + curr_dst = dst; + } + list_add_tail(&skb->list, &sublist); + } + /* dispatch final sublist */ + ip6_sublist_rcv_finish(&sublist); +} + +static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev, + struct net *net) +{ + enum skb_drop_reason reason; + const struct ipv6hdr *hdr; + u32 pkt_len; + struct inet6_dev *idev; + + if (skb->pkt_type == PACKET_OTHERHOST) { + dev_core_stats_rx_otherhost_dropped_inc(skb->dev); + kfree_skb_reason(skb, SKB_DROP_REASON_OTHERHOST); + return NULL; + } + + rcu_read_lock(); + + idev = __in6_dev_get(skb->dev); + + __IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_IN, skb->len); + + SKB_DR_SET(reason, NOT_SPECIFIED); + if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL || + !idev || unlikely(idev->cnf.disable_ipv6)) { + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS); + if (idev && unlikely(idev->cnf.disable_ipv6)) + SKB_DR_SET(reason, IPV6DISABLED); + goto drop; + } + + memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm)); + + /* + * Store incoming device index. When the packet will + * be queued, we cannot refer to skb->dev anymore. + * + * BTW, when we send a packet for our own local address on a + * non-loopback interface (e.g. ethX), it is being delivered + * via the loopback interface (lo) here; skb->dev = loopback_dev. + * It, however, should be considered as if it is being + * arrived via the sending interface (ethX), because of the + * nature of scoping architecture. --yoshfuji + */ + IP6CB(skb)->iif = skb_valid_dst(skb) ? ip6_dst_idev(skb_dst(skb))->dev->ifindex : dev->ifindex; + + if (unlikely(!pskb_may_pull(skb, sizeof(*hdr)))) + goto err; + + hdr = ipv6_hdr(skb); + + if (hdr->version != 6) { + SKB_DR_SET(reason, UNHANDLED_PROTO); + goto err; + } + + __IP6_ADD_STATS(net, idev, + IPSTATS_MIB_NOECTPKTS + + (ipv6_get_dsfield(hdr) & INET_ECN_MASK), + max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs)); + /* + * RFC4291 2.5.3 + * The loopback address must not be used as the source address in IPv6 + * packets that are sent outside of a single node. [..] + * A packet received on an interface with a destination address + * of loopback must be dropped. + */ + if ((ipv6_addr_loopback(&hdr->saddr) || + ipv6_addr_loopback(&hdr->daddr)) && + !(dev->flags & IFF_LOOPBACK) && + !netif_is_l3_master(dev)) + goto err; + + /* RFC4291 Errata ID: 3480 + * Interface-Local scope spans only a single interface on a + * node and is useful only for loopback transmission of + * multicast. Packets with interface-local scope received + * from another node must be discarded. + */ + if (!(skb->pkt_type == PACKET_LOOPBACK || + dev->flags & IFF_LOOPBACK) && + ipv6_addr_is_multicast(&hdr->daddr) && + IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 1) + goto err; + + /* If enabled, drop unicast packets that were encapsulated in link-layer + * multicast or broadcast to protected against the so-called "hole-196" + * attack in 802.11 wireless. + */ + if (!ipv6_addr_is_multicast(&hdr->daddr) && + (skb->pkt_type == PACKET_BROADCAST || + skb->pkt_type == PACKET_MULTICAST) && + idev->cnf.drop_unicast_in_l2_multicast) { + SKB_DR_SET(reason, UNICAST_IN_L2_MULTICAST); + goto err; + } + + /* RFC4291 2.7 + * Nodes must not originate a packet to a multicast address whose scope + * field contains the reserved value 0; if such a packet is received, it + * must be silently dropped. + */ + if (ipv6_addr_is_multicast(&hdr->daddr) && + IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 0) + goto err; + + /* + * RFC4291 2.7 + * Multicast addresses must not be used as source addresses in IPv6 + * packets or appear in any Routing header. + */ + if (ipv6_addr_is_multicast(&hdr->saddr)) + goto err; + + skb->transport_header = skb->network_header + sizeof(*hdr); + IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr); + + pkt_len = ntohs(hdr->payload_len); + + /* pkt_len may be zero if Jumbo payload option is present */ + if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) { + if (pkt_len + sizeof(struct ipv6hdr) > skb->len) { + __IP6_INC_STATS(net, + idev, IPSTATS_MIB_INTRUNCATEDPKTS); + SKB_DR_SET(reason, PKT_TOO_SMALL); + goto drop; + } + if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) + goto err; + hdr = ipv6_hdr(skb); + } + + if (hdr->nexthdr == NEXTHDR_HOP) { + if (ipv6_parse_hopopts(skb) < 0) { + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); + rcu_read_unlock(); + return NULL; + } + } + + rcu_read_unlock(); + + /* Must drop socket now because of tproxy. */ + if (!skb_sk_is_prefetched(skb)) + skb_orphan(skb); + + return skb; +err: + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); + SKB_DR_OR(reason, IP_INHDR); +drop: + rcu_read_unlock(); + kfree_skb_reason(skb, reason); + return NULL; +} + +int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev) +{ + struct net *net = dev_net(skb->dev); + + skb = ip6_rcv_core(skb, dev, net); + if (skb == NULL) + return NET_RX_DROP; + return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, + net, NULL, skb, dev, NULL, + ip6_rcv_finish); +} + +static void ip6_sublist_rcv(struct list_head *head, struct net_device *dev, + struct net *net) +{ + NF_HOOK_LIST(NFPROTO_IPV6, NF_INET_PRE_ROUTING, net, NULL, + head, dev, NULL, ip6_rcv_finish); + ip6_list_rcv_finish(net, NULL, head); +} + +/* Receive a list of IPv6 packets */ +void ipv6_list_rcv(struct list_head *head, struct packet_type *pt, + struct net_device *orig_dev) +{ + struct net_device *curr_dev = NULL; + struct net *curr_net = NULL; + struct sk_buff *skb, *next; + struct list_head sublist; + + INIT_LIST_HEAD(&sublist); + list_for_each_entry_safe(skb, next, head, list) { + struct net_device *dev = skb->dev; + struct net *net = dev_net(dev); + + skb_list_del_init(skb); + skb = ip6_rcv_core(skb, dev, net); + if (skb == NULL) + continue; + + if (curr_dev != dev || curr_net != net) { + /* dispatch old sublist */ + if (!list_empty(&sublist)) + ip6_sublist_rcv(&sublist, curr_dev, curr_net); + /* start new sublist */ + INIT_LIST_HEAD(&sublist); + curr_dev = dev; + curr_net = net; + } + list_add_tail(&skb->list, &sublist); + } + /* dispatch final sublist */ + if (!list_empty(&sublist)) + ip6_sublist_rcv(&sublist, curr_dev, curr_net); +} + +INDIRECT_CALLABLE_DECLARE(int tcp_v6_rcv(struct sk_buff *)); + +/* + * Deliver the packet to the host + */ +void ip6_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int nexthdr, + bool have_final) +{ + const struct inet6_protocol *ipprot; + struct inet6_dev *idev; + unsigned int nhoff; + SKB_DR(reason); + bool raw; + + /* + * Parse extension headers + */ + +resubmit: + idev = ip6_dst_idev(skb_dst(skb)); + nhoff = IP6CB(skb)->nhoff; + if (!have_final) { + if (!pskb_pull(skb, skb_transport_offset(skb))) + goto discard; + nexthdr = skb_network_header(skb)[nhoff]; + } + +resubmit_final: + raw = raw6_local_deliver(skb, nexthdr); + ipprot = rcu_dereference(inet6_protos[nexthdr]); + if (ipprot) { + int ret; + + if (have_final) { + if (!(ipprot->flags & INET6_PROTO_FINAL)) { + /* Once we've seen a final protocol don't + * allow encapsulation on any non-final + * ones. This allows foo in UDP encapsulation + * to work. + */ + goto discard; + } + } else if (ipprot->flags & INET6_PROTO_FINAL) { + const struct ipv6hdr *hdr; + int sdif = inet6_sdif(skb); + struct net_device *dev; + + /* Only do this once for first final protocol */ + have_final = true; + + + skb_postpull_rcsum(skb, skb_network_header(skb), + skb_network_header_len(skb)); + hdr = ipv6_hdr(skb); + + /* skb->dev passed may be master dev for vrfs. */ + if (sdif) { + dev = dev_get_by_index_rcu(net, sdif); + if (!dev) + goto discard; + } else { + dev = skb->dev; + } + + if (ipv6_addr_is_multicast(&hdr->daddr) && + !ipv6_chk_mcast_addr(dev, &hdr->daddr, + &hdr->saddr) && + !ipv6_is_mld(skb, nexthdr, skb_network_header_len(skb))) { + SKB_DR_SET(reason, IP_INADDRERRORS); + goto discard; + } + } + if (!(ipprot->flags & INET6_PROTO_NOPOLICY)) { + if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { + SKB_DR_SET(reason, XFRM_POLICY); + goto discard; + } + nf_reset_ct(skb); + } + + ret = INDIRECT_CALL_2(ipprot->handler, tcp_v6_rcv, udpv6_rcv, + skb); + if (ret > 0) { + if (ipprot->flags & INET6_PROTO_FINAL) { + /* Not an extension header, most likely UDP + * encapsulation. Use return value as nexthdr + * protocol not nhoff (which presumably is + * not set by handler). + */ + nexthdr = ret; + goto resubmit_final; + } else { + goto resubmit; + } + } else if (ret == 0) { + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS); + } + } else { + if (!raw) { + if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { + __IP6_INC_STATS(net, idev, + IPSTATS_MIB_INUNKNOWNPROTOS); + icmpv6_send(skb, ICMPV6_PARAMPROB, + ICMPV6_UNK_NEXTHDR, nhoff); + SKB_DR_SET(reason, IP_NOPROTO); + } else { + SKB_DR_SET(reason, XFRM_POLICY); + } + kfree_skb_reason(skb, reason); + } else { + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS); + consume_skb(skb); + } + } + return; + +discard: + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS); + kfree_skb_reason(skb, reason); +} + +static int ip6_input_finish(struct net *net, struct sock *sk, struct sk_buff *skb) +{ + skb_clear_delivery_time(skb); + rcu_read_lock(); + ip6_protocol_deliver_rcu(net, skb, 0, false); + rcu_read_unlock(); + + return 0; +} + + +int ip6_input(struct sk_buff *skb) +{ + return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN, + dev_net(skb->dev), NULL, skb, skb->dev, NULL, + ip6_input_finish); +} +EXPORT_SYMBOL_GPL(ip6_input); + +int ip6_mc_input(struct sk_buff *skb) +{ + int sdif = inet6_sdif(skb); + const struct ipv6hdr *hdr; + struct net_device *dev; + bool deliver; + + __IP6_UPD_PO_STATS(dev_net(skb_dst(skb)->dev), + __in6_dev_get_safely(skb->dev), IPSTATS_MIB_INMCAST, + skb->len); + + /* skb->dev passed may be master dev for vrfs. */ + if (sdif) { + rcu_read_lock(); + dev = dev_get_by_index_rcu(dev_net(skb->dev), sdif); + if (!dev) { + rcu_read_unlock(); + kfree_skb(skb); + return -ENODEV; + } + } else { + dev = skb->dev; + } + + hdr = ipv6_hdr(skb); + deliver = ipv6_chk_mcast_addr(dev, &hdr->daddr, NULL); + if (sdif) + rcu_read_unlock(); + +#ifdef CONFIG_IPV6_MROUTE + /* + * IPv6 multicast router mode is now supported ;) + */ + if (atomic_read(&dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding) && + !(ipv6_addr_type(&hdr->daddr) & + (IPV6_ADDR_LOOPBACK|IPV6_ADDR_LINKLOCAL)) && + likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) { + /* + * Okay, we try to forward - split and duplicate + * packets. + */ + struct sk_buff *skb2; + struct inet6_skb_parm *opt = IP6CB(skb); + + /* Check for MLD */ + if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) { + /* Check if this is a mld message */ + u8 nexthdr = hdr->nexthdr; + __be16 frag_off; + int offset; + + /* Check if the value of Router Alert + * is for MLD (0x0000). + */ + if (opt->ra == htons(IPV6_OPT_ROUTERALERT_MLD)) { + deliver = false; + + if (!ipv6_ext_hdr(nexthdr)) { + /* BUG */ + goto out; + } + offset = ipv6_skip_exthdr(skb, sizeof(*hdr), + &nexthdr, &frag_off); + if (offset < 0) + goto out; + + if (ipv6_is_mld(skb, nexthdr, offset)) + deliver = true; + + goto out; + } + /* unknown RA - process it normally */ + } + + if (deliver) + skb2 = skb_clone(skb, GFP_ATOMIC); + else { + skb2 = skb; + skb = NULL; + } + + if (skb2) { + ip6_mr_input(skb2); + } + } +out: +#endif + if (likely(deliver)) + ip6_input(skb); + else { + /* discard */ + kfree_skb(skb); + } + + return 0; +} -- cgit v1.2.3