diff options
Diffstat (limited to 'net/ipv6/exthdrs.c')
| -rw-r--r-- | net/ipv6/exthdrs.c | 1401 |
1 files changed, 1401 insertions, 0 deletions
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c new file mode 100644 index 000000000..5fa0e3730 --- /dev/null +++ b/net/ipv6/exthdrs.c @@ -0,0 +1,1401 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Extension Header handling for IPv6 + * Linux INET6 implementation + * + * Authors: + * Pedro Roque <roque@di.fc.ul.pt> + * Andi Kleen <ak@muc.de> + * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> + */ + +/* Changes: + * yoshfuji : ensure not to overrun while parsing + * tlv options. + * Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs(). + * YOSHIFUJI Hideaki @USAGI Register inbound extension header + * handlers as inet6_protocol{}. + */ + +#include <linux/errno.h> +#include <linux/types.h> +#include <linux/socket.h> +#include <linux/sockios.h> +#include <linux/net.h> +#include <linux/netdevice.h> +#include <linux/in6.h> +#include <linux/icmpv6.h> +#include <linux/slab.h> +#include <linux/export.h> + +#include <net/dst.h> +#include <net/sock.h> +#include <net/snmp.h> + +#include <net/ipv6.h> +#include <net/protocol.h> +#include <net/transp_v6.h> +#include <net/rawv6.h> +#include <net/ndisc.h> +#include <net/ip6_route.h> +#include <net/addrconf.h> +#include <net/calipso.h> +#if IS_ENABLED(CONFIG_IPV6_MIP6) +#include <net/xfrm.h> +#endif +#include <linux/seg6.h> +#include <net/seg6.h> +#ifdef CONFIG_IPV6_SEG6_HMAC +#include <net/seg6_hmac.h> +#endif +#include <net/rpl.h> +#include <linux/ioam6.h> +#include <net/ioam6.h> +#include <net/dst_metadata.h> + +#include <linux/uaccess.h> + +/********************* + Generic functions + *********************/ + +/* An unknown option is detected, decide what to do */ + +static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff, + bool disallow_unknowns) +{ + if (disallow_unknowns) { + /* If unknown TLVs are disallowed by configuration + * then always silently drop packet. Note this also + * means no ICMP parameter problem is sent which + * could be a good property to mitigate a reflection DOS + * attack. + */ + + goto drop; + } + + switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) { + case 0: /* ignore */ + return true; + + case 1: /* drop packet */ + break; + + case 3: /* Send ICMP if not a multicast address and drop packet */ + /* Actually, it is redundant check. icmp_send + will recheck in any case. + */ + if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) + break; + fallthrough; + case 2: /* send ICMP PARM PROB regardless and drop packet */ + icmpv6_param_prob_reason(skb, ICMPV6_UNK_OPTION, optoff, + SKB_DROP_REASON_UNHANDLED_PROTO); + return false; + } + +drop: + kfree_skb_reason(skb, SKB_DROP_REASON_UNHANDLED_PROTO); + return false; +} + +static bool ipv6_hop_ra(struct sk_buff *skb, int optoff); +static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff); +static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff); +static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff); +#if IS_ENABLED(CONFIG_IPV6_MIP6) +static bool ipv6_dest_hao(struct sk_buff *skb, int optoff); +#endif + +/* Parse tlv encoded option header (hop-by-hop or destination) */ + +static bool ip6_parse_tlv(bool hopbyhop, + struct sk_buff *skb, + int max_count) +{ + int len = (skb_transport_header(skb)[1] + 1) << 3; + const unsigned char *nh = skb_network_header(skb); + int off = skb_network_header_len(skb); + bool disallow_unknowns = false; + int tlv_count = 0; + int padlen = 0; + + if (unlikely(max_count < 0)) { + disallow_unknowns = true; + max_count = -max_count; + } + + if (skb_transport_offset(skb) + len > skb_headlen(skb)) + goto bad; + + off += 2; + len -= 2; + + while (len > 0) { + int optlen, i; + + if (nh[off] == IPV6_TLV_PAD1) { + padlen++; + if (padlen > 7) + goto bad; + off++; + len--; + continue; + } + if (len < 2) + goto bad; + optlen = nh[off + 1] + 2; + if (optlen > len) + goto bad; + + if (nh[off] == IPV6_TLV_PADN) { + /* RFC 2460 states that the purpose of PadN is + * to align the containing header to multiples + * of 8. 7 is therefore the highest valid value. + * See also RFC 4942, Section 2.1.9.5. + */ + padlen += optlen; + if (padlen > 7) + goto bad; + /* RFC 4942 recommends receiving hosts to + * actively check PadN payload to contain + * only zeroes. + */ + for (i = 2; i < optlen; i++) { + if (nh[off + i] != 0) + goto bad; + } + } else { + tlv_count++; + if (tlv_count > max_count) + goto bad; + + if (hopbyhop) { + switch (nh[off]) { + case IPV6_TLV_ROUTERALERT: + if (!ipv6_hop_ra(skb, off)) + return false; + break; + case IPV6_TLV_IOAM: + if (!ipv6_hop_ioam(skb, off)) + return false; + break; + case IPV6_TLV_JUMBO: + if (!ipv6_hop_jumbo(skb, off)) + return false; + break; + case IPV6_TLV_CALIPSO: + if (!ipv6_hop_calipso(skb, off)) + return false; + break; + default: + if (!ip6_tlvopt_unknown(skb, off, + disallow_unknowns)) + return false; + break; + } + } else { + switch (nh[off]) { +#if IS_ENABLED(CONFIG_IPV6_MIP6) + case IPV6_TLV_HAO: + if (!ipv6_dest_hao(skb, off)) + return false; + break; +#endif + default: + if (!ip6_tlvopt_unknown(skb, off, + disallow_unknowns)) + return false; + break; + } + } + padlen = 0; + } + off += optlen; + len -= optlen; + } + + if (len == 0) + return true; +bad: + kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); + return false; +} + +/***************************** + Destination options header. + *****************************/ + +#if IS_ENABLED(CONFIG_IPV6_MIP6) +static bool ipv6_dest_hao(struct sk_buff *skb, int optoff) +{ + struct ipv6_destopt_hao *hao; + struct inet6_skb_parm *opt = IP6CB(skb); + struct ipv6hdr *ipv6h = ipv6_hdr(skb); + SKB_DR(reason); + int ret; + + if (opt->dsthao) { + net_dbg_ratelimited("hao duplicated\n"); + goto discard; + } + opt->dsthao = opt->dst1; + opt->dst1 = 0; + + hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff); + + if (hao->length != 16) { + net_dbg_ratelimited("hao invalid option length = %d\n", + hao->length); + SKB_DR_SET(reason, IP_INHDR); + goto discard; + } + + if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) { + net_dbg_ratelimited("hao is not an unicast addr: %pI6\n", + &hao->addr); + SKB_DR_SET(reason, INVALID_PROTO); + goto discard; + } + + ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr, + (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS); + if (unlikely(ret < 0)) { + SKB_DR_SET(reason, XFRM_POLICY); + goto discard; + } + + if (skb_cloned(skb)) { + if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) + goto discard; + + /* update all variable using below by copied skbuff */ + hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + + optoff); + ipv6h = ipv6_hdr(skb); + } + + if (skb->ip_summed == CHECKSUM_COMPLETE) + skb->ip_summed = CHECKSUM_NONE; + + swap(ipv6h->saddr, hao->addr); + + if (skb->tstamp == 0) + __net_timestamp(skb); + + return true; + + discard: + kfree_skb_reason(skb, reason); + return false; +} +#endif + +static int ipv6_destopt_rcv(struct sk_buff *skb) +{ + struct inet6_dev *idev = __in6_dev_get(skb->dev); + struct inet6_skb_parm *opt = IP6CB(skb); +#if IS_ENABLED(CONFIG_IPV6_MIP6) + __u16 dstbuf; +#endif + struct dst_entry *dst = skb_dst(skb); + struct net *net = dev_net(skb->dev); + int extlen; + + if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || + !pskb_may_pull(skb, (skb_transport_offset(skb) + + ((skb_transport_header(skb)[1] + 1) << 3)))) { + __IP6_INC_STATS(dev_net(dst->dev), idev, + IPSTATS_MIB_INHDRERRORS); +fail_and_free: + kfree_skb(skb); + return -1; + } + + extlen = (skb_transport_header(skb)[1] + 1) << 3; + if (extlen > net->ipv6.sysctl.max_dst_opts_len) + goto fail_and_free; + + opt->lastopt = opt->dst1 = skb_network_header_len(skb); +#if IS_ENABLED(CONFIG_IPV6_MIP6) + dstbuf = opt->dst1; +#endif + + if (ip6_parse_tlv(false, skb, net->ipv6.sysctl.max_dst_opts_cnt)) { + skb->transport_header += extlen; + opt = IP6CB(skb); +#if IS_ENABLED(CONFIG_IPV6_MIP6) + opt->nhoff = dstbuf; +#else + opt->nhoff = opt->dst1; +#endif + return 1; + } + + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); + return -1; +} + +static void seg6_update_csum(struct sk_buff *skb) +{ + struct ipv6_sr_hdr *hdr; + struct in6_addr *addr; + __be32 from, to; + + /* srh is at transport offset and seg_left is already decremented + * but daddr is not yet updated with next segment + */ + + hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); + addr = hdr->segments + hdr->segments_left; + + hdr->segments_left++; + from = *(__be32 *)hdr; + + hdr->segments_left--; + to = *(__be32 *)hdr; + + /* update skb csum with diff resulting from seg_left decrement */ + + update_csum_diff4(skb, from, to); + + /* compute csum diff between current and next segment and update */ + + update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr), + (__be32 *)addr); +} + +static int ipv6_srh_rcv(struct sk_buff *skb) +{ + struct inet6_skb_parm *opt = IP6CB(skb); + struct net *net = dev_net(skb->dev); + struct ipv6_sr_hdr *hdr; + struct inet6_dev *idev; + struct in6_addr *addr; + int accept_seg6; + + hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); + + idev = __in6_dev_get(skb->dev); + + accept_seg6 = net->ipv6.devconf_all->seg6_enabled; + if (accept_seg6 > idev->cnf.seg6_enabled) + accept_seg6 = idev->cnf.seg6_enabled; + + if (!accept_seg6) { + kfree_skb(skb); + return -1; + } + +#ifdef CONFIG_IPV6_SEG6_HMAC + if (!seg6_hmac_validate_skb(skb)) { + kfree_skb(skb); + return -1; + } +#endif + +looped_back: + if (hdr->segments_left == 0) { + if (hdr->nexthdr == NEXTHDR_IPV6 || hdr->nexthdr == NEXTHDR_IPV4) { + int offset = (hdr->hdrlen + 1) << 3; + + skb_postpull_rcsum(skb, skb_network_header(skb), + skb_network_header_len(skb)); + + if (!pskb_pull(skb, offset)) { + kfree_skb(skb); + return -1; + } + skb_postpull_rcsum(skb, skb_transport_header(skb), + offset); + + skb_reset_network_header(skb); + skb_reset_transport_header(skb); + skb->encapsulation = 0; + if (hdr->nexthdr == NEXTHDR_IPV4) + skb->protocol = htons(ETH_P_IP); + __skb_tunnel_rx(skb, skb->dev, net); + + netif_rx(skb); + return -1; + } + + opt->srcrt = skb_network_header_len(skb); + opt->lastopt = opt->srcrt; + skb->transport_header += (hdr->hdrlen + 1) << 3; + opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); + + return 1; + } + + if (hdr->segments_left >= (hdr->hdrlen >> 1)) { + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); + icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, + ((&hdr->segments_left) - + skb_network_header(skb))); + return -1; + } + + if (skb_cloned(skb)) { + if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { + __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), + IPSTATS_MIB_OUTDISCARDS); + kfree_skb(skb); + return -1; + } + } + + hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); + + hdr->segments_left--; + addr = hdr->segments + hdr->segments_left; + + skb_push(skb, sizeof(struct ipv6hdr)); + + if (skb->ip_summed == CHECKSUM_COMPLETE) + seg6_update_csum(skb); + + ipv6_hdr(skb)->daddr = *addr; + + skb_dst_drop(skb); + + ip6_route_input(skb); + + if (skb_dst(skb)->error) { + dst_input(skb); + return -1; + } + + if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) { + if (ipv6_hdr(skb)->hop_limit <= 1) { + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); + icmpv6_send(skb, ICMPV6_TIME_EXCEED, + ICMPV6_EXC_HOPLIMIT, 0); + kfree_skb(skb); + return -1; + } + ipv6_hdr(skb)->hop_limit--; + + skb_pull(skb, sizeof(struct ipv6hdr)); + goto looped_back; + } + + dst_input(skb); + + return -1; +} + +static int ipv6_rpl_srh_rcv(struct sk_buff *skb) +{ + struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr; + struct inet6_skb_parm *opt = IP6CB(skb); + struct net *net = dev_net(skb->dev); + struct inet6_dev *idev; + struct ipv6hdr *oldhdr; + unsigned char *buf; + int accept_rpl_seg; + int i, err; + u64 n = 0; + u32 r; + + idev = __in6_dev_get(skb->dev); + + accept_rpl_seg = net->ipv6.devconf_all->rpl_seg_enabled; + if (accept_rpl_seg > idev->cnf.rpl_seg_enabled) + accept_rpl_seg = idev->cnf.rpl_seg_enabled; + + if (!accept_rpl_seg) { + kfree_skb(skb); + return -1; + } + +looped_back: + hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb); + + if (hdr->segments_left == 0) { + if (hdr->nexthdr == NEXTHDR_IPV6) { + int offset = (hdr->hdrlen + 1) << 3; + + skb_postpull_rcsum(skb, skb_network_header(skb), + skb_network_header_len(skb)); + + if (!pskb_pull(skb, offset)) { + kfree_skb(skb); + return -1; + } + skb_postpull_rcsum(skb, skb_transport_header(skb), + offset); + + skb_reset_network_header(skb); + skb_reset_transport_header(skb); + skb->encapsulation = 0; + + __skb_tunnel_rx(skb, skb->dev, net); + + netif_rx(skb); + return -1; + } + + opt->srcrt = skb_network_header_len(skb); + opt->lastopt = opt->srcrt; + skb->transport_header += (hdr->hdrlen + 1) << 3; + opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); + + return 1; + } + + if (!pskb_may_pull(skb, sizeof(*hdr))) { + kfree_skb(skb); + return -1; + } + + n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre); + r = do_div(n, (16 - hdr->cmpri)); + /* checks if calculation was without remainder and n fits into + * unsigned char which is segments_left field. Should not be + * higher than that. + */ + if (r || (n + 1) > 255) { + kfree_skb(skb); + return -1; + } + + if (hdr->segments_left > n + 1) { + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); + icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, + ((&hdr->segments_left) - + skb_network_header(skb))); + return -1; + } + + if (!pskb_may_pull(skb, ipv6_rpl_srh_size(n, hdr->cmpri, + hdr->cmpre))) { + kfree_skb(skb); + return -1; + } + + hdr->segments_left--; + i = n - hdr->segments_left; + + buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC); + if (unlikely(!buf)) { + kfree_skb(skb); + return -1; + } + + ohdr = (struct ipv6_rpl_sr_hdr *)buf; + ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n); + chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3)); + + if ((ipv6_addr_type(&ipv6_hdr(skb)->daddr) & IPV6_ADDR_MULTICAST) || + (ipv6_addr_type(&ohdr->rpl_segaddr[i]) & IPV6_ADDR_MULTICAST)) { + kfree_skb(skb); + kfree(buf); + return -1; + } + + err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1); + if (err) { + icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0); + kfree_skb(skb); + kfree(buf); + return -1; + } + + swap(ipv6_hdr(skb)->daddr, ohdr->rpl_segaddr[i]); + + ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n); + + oldhdr = ipv6_hdr(skb); + + skb_pull(skb, ((hdr->hdrlen + 1) << 3)); + skb_postpull_rcsum(skb, oldhdr, + sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3)); + if (unlikely(!hdr->segments_left)) { + if (pskb_expand_head(skb, sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3), 0, + GFP_ATOMIC)) { + __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_OUTDISCARDS); + kfree_skb(skb); + kfree(buf); + return -1; + } + + oldhdr = ipv6_hdr(skb); + } + skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr)); + skb_reset_network_header(skb); + skb_mac_header_rebuild(skb); + skb_set_transport_header(skb, sizeof(struct ipv6hdr)); + + memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr)); + memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3); + + ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); + skb_postpush_rcsum(skb, ipv6_hdr(skb), + sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3)); + + kfree(buf); + + skb_dst_drop(skb); + + ip6_route_input(skb); + + if (skb_dst(skb)->error) { + dst_input(skb); + return -1; + } + + if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) { + if (ipv6_hdr(skb)->hop_limit <= 1) { + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); + icmpv6_send(skb, ICMPV6_TIME_EXCEED, + ICMPV6_EXC_HOPLIMIT, 0); + kfree_skb(skb); + return -1; + } + ipv6_hdr(skb)->hop_limit--; + + skb_pull(skb, sizeof(struct ipv6hdr)); + goto looped_back; + } + + dst_input(skb); + + return -1; +} + +/******************************** + Routing header. + ********************************/ + +/* called with rcu_read_lock() */ +static int ipv6_rthdr_rcv(struct sk_buff *skb) +{ + struct inet6_dev *idev = __in6_dev_get(skb->dev); + struct inet6_skb_parm *opt = IP6CB(skb); + struct in6_addr *addr = NULL; + struct in6_addr daddr; + int n, i; + struct ipv6_rt_hdr *hdr; + struct rt0_hdr *rthdr; + struct net *net = dev_net(skb->dev); + int accept_source_route = net->ipv6.devconf_all->accept_source_route; + + if (idev && accept_source_route > idev->cnf.accept_source_route) + accept_source_route = idev->cnf.accept_source_route; + + if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || + !pskb_may_pull(skb, (skb_transport_offset(skb) + + ((skb_transport_header(skb)[1] + 1) << 3)))) { + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); + kfree_skb(skb); + return -1; + } + + hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); + + if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) || + skb->pkt_type != PACKET_HOST) { + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); + kfree_skb(skb); + return -1; + } + + switch (hdr->type) { + case IPV6_SRCRT_TYPE_4: + /* segment routing */ + return ipv6_srh_rcv(skb); + case IPV6_SRCRT_TYPE_3: + /* rpl segment routing */ + return ipv6_rpl_srh_rcv(skb); + default: + break; + } + +looped_back: + if (hdr->segments_left == 0) { + switch (hdr->type) { +#if IS_ENABLED(CONFIG_IPV6_MIP6) + case IPV6_SRCRT_TYPE_2: + /* Silently discard type 2 header unless it was + * processed by own + */ + if (!addr) { + __IP6_INC_STATS(net, idev, + IPSTATS_MIB_INADDRERRORS); + kfree_skb(skb); + return -1; + } + break; +#endif + default: + break; + } + + opt->lastopt = opt->srcrt = skb_network_header_len(skb); + skb->transport_header += (hdr->hdrlen + 1) << 3; + opt->dst0 = opt->dst1; + opt->dst1 = 0; + opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); + return 1; + } + + switch (hdr->type) { +#if IS_ENABLED(CONFIG_IPV6_MIP6) + case IPV6_SRCRT_TYPE_2: + if (accept_source_route < 0) + goto unknown_rh; + /* Silently discard invalid RTH type 2 */ + if (hdr->hdrlen != 2 || hdr->segments_left != 1) { + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); + kfree_skb(skb); + return -1; + } + break; +#endif + default: + goto unknown_rh; + } + + /* + * This is the routing header forwarding algorithm from + * RFC 2460, page 16. + */ + + n = hdr->hdrlen >> 1; + + if (hdr->segments_left > n) { + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); + icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, + ((&hdr->segments_left) - + skb_network_header(skb))); + return -1; + } + + /* We are about to mangle packet header. Be careful! + Do not damage packets queued somewhere. + */ + if (skb_cloned(skb)) { + /* the copy is a forwarded packet */ + if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { + __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), + IPSTATS_MIB_OUTDISCARDS); + kfree_skb(skb); + return -1; + } + hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); + } + + if (skb->ip_summed == CHECKSUM_COMPLETE) + skb->ip_summed = CHECKSUM_NONE; + + i = n - --hdr->segments_left; + + rthdr = (struct rt0_hdr *) hdr; + addr = rthdr->addr; + addr += i - 1; + + switch (hdr->type) { +#if IS_ENABLED(CONFIG_IPV6_MIP6) + case IPV6_SRCRT_TYPE_2: + if (xfrm6_input_addr(skb, (xfrm_address_t *)addr, + (xfrm_address_t *)&ipv6_hdr(skb)->saddr, + IPPROTO_ROUTING) < 0) { + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); + kfree_skb(skb); + return -1; + } + if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) { + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); + kfree_skb(skb); + return -1; + } + break; +#endif + default: + break; + } + + if (ipv6_addr_is_multicast(addr)) { + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); + kfree_skb(skb); + return -1; + } + + daddr = *addr; + *addr = ipv6_hdr(skb)->daddr; + ipv6_hdr(skb)->daddr = daddr; + + skb_dst_drop(skb); + ip6_route_input(skb); + if (skb_dst(skb)->error) { + skb_push(skb, skb->data - skb_network_header(skb)); + dst_input(skb); + return -1; + } + + if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) { + if (ipv6_hdr(skb)->hop_limit <= 1) { + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); + icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, + 0); + kfree_skb(skb); + return -1; + } + ipv6_hdr(skb)->hop_limit--; + goto looped_back; + } + + skb_push(skb, skb->data - skb_network_header(skb)); + dst_input(skb); + return -1; + +unknown_rh: + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); + icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, + (&hdr->type) - skb_network_header(skb)); + return -1; +} + +static const struct inet6_protocol rthdr_protocol = { + .handler = ipv6_rthdr_rcv, + .flags = INET6_PROTO_NOPOLICY, +}; + +static const struct inet6_protocol destopt_protocol = { + .handler = ipv6_destopt_rcv, + .flags = INET6_PROTO_NOPOLICY, +}; + +static const struct inet6_protocol nodata_protocol = { + .handler = dst_discard, + .flags = INET6_PROTO_NOPOLICY, +}; + +int __init ipv6_exthdrs_init(void) +{ + int ret; + + ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING); + if (ret) + goto out; + + ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS); + if (ret) + goto out_rthdr; + + ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE); + if (ret) + goto out_destopt; + +out: + return ret; +out_destopt: + inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); +out_rthdr: + inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); + goto out; +}; + +void ipv6_exthdrs_exit(void) +{ + inet6_del_protocol(&nodata_protocol, IPPROTO_NONE); + inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); + inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); +} + +/********************************** + Hop-by-hop options. + **********************************/ + +/* + * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input(). + */ +static inline struct net *ipv6_skb_net(struct sk_buff *skb) +{ + return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev); +} + +/* Router Alert as of RFC 2711 */ + +static bool ipv6_hop_ra(struct sk_buff *skb, int optoff) +{ + const unsigned char *nh = skb_network_header(skb); + + if (nh[optoff + 1] == 2) { + IP6CB(skb)->flags |= IP6SKB_ROUTERALERT; + memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra)); + return true; + } + net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n", + nh[optoff + 1]); + kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); + return false; +} + +/* IOAM */ + +static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff) +{ + struct ioam6_trace_hdr *trace; + struct ioam6_namespace *ns; + struct ioam6_hdr *hdr; + + /* Bad alignment (must be 4n-aligned) */ + if (optoff & 3) + goto drop; + + /* Ignore if IOAM is not enabled on ingress */ + if (!__in6_dev_get(skb->dev)->cnf.ioam6_enabled) + goto ignore; + + /* Truncated Option header */ + hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff); + if (hdr->opt_len < 2) + goto drop; + + switch (hdr->type) { + case IOAM6_TYPE_PREALLOC: + /* Truncated Pre-allocated Trace header */ + if (hdr->opt_len < 2 + sizeof(*trace)) + goto drop; + + /* Malformed Pre-allocated Trace header */ + trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr)); + if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4) + goto drop; + + /* Ignore if the IOAM namespace is unknown */ + ns = ioam6_namespace(ipv6_skb_net(skb), trace->namespace_id); + if (!ns) + goto ignore; + + if (!skb_valid_dst(skb)) + ip6_route_input(skb); + + ioam6_fill_trace_data(skb, ns, trace, true); + break; + default: + break; + } + +ignore: + return true; + +drop: + kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); + return false; +} + +/* Jumbo payload */ + +static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff) +{ + const unsigned char *nh = skb_network_header(skb); + SKB_DR(reason); + u32 pkt_len; + + if (nh[optoff + 1] != 4 || (optoff & 3) != 2) { + net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", + nh[optoff+1]); + SKB_DR_SET(reason, IP_INHDR); + goto drop; + } + + pkt_len = ntohl(*(__be32 *)(nh + optoff + 2)); + if (pkt_len <= IPV6_MAXPLEN) { + icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff + 2, + SKB_DROP_REASON_IP_INHDR); + return false; + } + if (ipv6_hdr(skb)->payload_len) { + icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff, + SKB_DROP_REASON_IP_INHDR); + return false; + } + + if (pkt_len > skb->len - sizeof(struct ipv6hdr)) { + SKB_DR_SET(reason, PKT_TOO_SMALL); + goto drop; + } + + if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) + goto drop; + + IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM; + return true; + +drop: + kfree_skb_reason(skb, reason); + return false; +} + +/* CALIPSO RFC 5570 */ + +static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff) +{ + const unsigned char *nh = skb_network_header(skb); + + if (nh[optoff + 1] < 8) + goto drop; + + if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1]) + goto drop; + + if (!calipso_validate(skb, nh + optoff)) + goto drop; + + return true; + +drop: + kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); + return false; +} + +int ipv6_parse_hopopts(struct sk_buff *skb) +{ + struct inet6_skb_parm *opt = IP6CB(skb); + struct net *net = dev_net(skb->dev); + int extlen; + + /* + * skb_network_header(skb) is equal to skb->data, and + * skb_network_header_len(skb) is always equal to + * sizeof(struct ipv6hdr) by definition of + * hop-by-hop options. + */ + if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || + !pskb_may_pull(skb, (sizeof(struct ipv6hdr) + + ((skb_transport_header(skb)[1] + 1) << 3)))) { +fail_and_free: + kfree_skb(skb); + return -1; + } + + extlen = (skb_transport_header(skb)[1] + 1) << 3; + if (extlen > net->ipv6.sysctl.max_hbh_opts_len) + goto fail_and_free; + + opt->flags |= IP6SKB_HOPBYHOP; + if (ip6_parse_tlv(true, skb, net->ipv6.sysctl.max_hbh_opts_cnt)) { + skb->transport_header += extlen; + opt = IP6CB(skb); + opt->nhoff = sizeof(struct ipv6hdr); + return 1; + } + return -1; +} + +/* + * Creating outbound headers. + * + * "build" functions work when skb is filled from head to tail (datagram) + * "push" functions work when headers are added from tail to head (tcp) + * + * In both cases we assume, that caller reserved enough room + * for headers. + */ + +static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto, + struct ipv6_rt_hdr *opt, + struct in6_addr **addr_p, struct in6_addr *saddr) +{ + struct rt0_hdr *phdr, *ihdr; + int hops; + + ihdr = (struct rt0_hdr *) opt; + + phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3); + memcpy(phdr, ihdr, sizeof(struct rt0_hdr)); + + hops = ihdr->rt_hdr.hdrlen >> 1; + + if (hops > 1) + memcpy(phdr->addr, ihdr->addr + 1, + (hops - 1) * sizeof(struct in6_addr)); + + phdr->addr[hops - 1] = **addr_p; + *addr_p = ihdr->addr; + + phdr->rt_hdr.nexthdr = *proto; + *proto = NEXTHDR_ROUTING; +} + +static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto, + struct ipv6_rt_hdr *opt, + struct in6_addr **addr_p, struct in6_addr *saddr) +{ + struct ipv6_sr_hdr *sr_phdr, *sr_ihdr; + int plen, hops; + + sr_ihdr = (struct ipv6_sr_hdr *)opt; + plen = (sr_ihdr->hdrlen + 1) << 3; + + sr_phdr = skb_push(skb, plen); + memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr)); + + hops = sr_ihdr->first_segment + 1; + memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1, + (hops - 1) * sizeof(struct in6_addr)); + + sr_phdr->segments[0] = **addr_p; + *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left]; + + if (sr_ihdr->hdrlen > hops * 2) { + int tlvs_offset, tlvs_length; + + tlvs_offset = (1 + hops * 2) << 3; + tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3; + memcpy((char *)sr_phdr + tlvs_offset, + (char *)sr_ihdr + tlvs_offset, tlvs_length); + } + +#ifdef CONFIG_IPV6_SEG6_HMAC + if (sr_has_hmac(sr_phdr)) { + struct net *net = NULL; + + if (skb->dev) + net = dev_net(skb->dev); + else if (skb->sk) + net = sock_net(skb->sk); + + WARN_ON(!net); + + if (net) + seg6_push_hmac(net, saddr, sr_phdr); + } +#endif + + sr_phdr->nexthdr = *proto; + *proto = NEXTHDR_ROUTING; +} + +static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto, + struct ipv6_rt_hdr *opt, + struct in6_addr **addr_p, struct in6_addr *saddr) +{ + switch (opt->type) { + case IPV6_SRCRT_TYPE_0: + case IPV6_SRCRT_STRICT: + case IPV6_SRCRT_TYPE_2: + ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr); + break; + case IPV6_SRCRT_TYPE_4: + ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr); + break; + default: + break; + } +} + +static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt) +{ + struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt)); + + memcpy(h, opt, ipv6_optlen(opt)); + h->nexthdr = *proto; + *proto = type; +} + +void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, + u8 *proto, + struct in6_addr **daddr, struct in6_addr *saddr) +{ + if (opt->srcrt) { + ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr); + /* + * IPV6_RTHDRDSTOPTS is ignored + * unless IPV6_RTHDR is set (RFC3542). + */ + if (opt->dst0opt) + ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt); + } + if (opt->hopopt) + ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt); +} + +void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto) +{ + if (opt->dst1opt) + ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt); +} +EXPORT_SYMBOL(ipv6_push_frag_opts); + +struct ipv6_txoptions * +ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) +{ + struct ipv6_txoptions *opt2; + + opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC); + if (opt2) { + long dif = (char *)opt2 - (char *)opt; + memcpy(opt2, opt, opt->tot_len); + if (opt2->hopopt) + *((char **)&opt2->hopopt) += dif; + if (opt2->dst0opt) + *((char **)&opt2->dst0opt) += dif; + if (opt2->dst1opt) + *((char **)&opt2->dst1opt) += dif; + if (opt2->srcrt) + *((char **)&opt2->srcrt) += dif; + refcount_set(&opt2->refcnt, 1); + } + return opt2; +} +EXPORT_SYMBOL_GPL(ipv6_dup_options); + +static void ipv6_renew_option(int renewtype, + struct ipv6_opt_hdr **dest, + struct ipv6_opt_hdr *old, + struct ipv6_opt_hdr *new, + int newtype, char **p) +{ + struct ipv6_opt_hdr *src; + + src = (renewtype == newtype ? new : old); + if (!src) + return; + + memcpy(*p, src, ipv6_optlen(src)); + *dest = (struct ipv6_opt_hdr *)*p; + *p += CMSG_ALIGN(ipv6_optlen(*dest)); +} + +/** + * ipv6_renew_options - replace a specific ext hdr with a new one. + * + * @sk: sock from which to allocate memory + * @opt: original options + * @newtype: option type to replace in @opt + * @newopt: new option of type @newtype to replace (user-mem) + * + * Returns a new set of options which is a copy of @opt with the + * option type @newtype replaced with @newopt. + * + * @opt may be NULL, in which case a new set of options is returned + * containing just @newopt. + * + * @newopt may be NULL, in which case the specified option type is + * not copied into the new set of options. + * + * The new set of options is allocated from the socket option memory + * buffer of @sk. + */ +struct ipv6_txoptions * +ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, + int newtype, struct ipv6_opt_hdr *newopt) +{ + int tot_len = 0; + char *p; + struct ipv6_txoptions *opt2; + + if (opt) { + if (newtype != IPV6_HOPOPTS && opt->hopopt) + tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt)); + if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt) + tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt)); + if (newtype != IPV6_RTHDR && opt->srcrt) + tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt)); + if (newtype != IPV6_DSTOPTS && opt->dst1opt) + tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt)); + } + + if (newopt) + tot_len += CMSG_ALIGN(ipv6_optlen(newopt)); + + if (!tot_len) + return NULL; + + tot_len += sizeof(*opt2); + opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC); + if (!opt2) + return ERR_PTR(-ENOBUFS); + + memset(opt2, 0, tot_len); + refcount_set(&opt2->refcnt, 1); + opt2->tot_len = tot_len; + p = (char *)(opt2 + 1); + + ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt, + (opt ? opt->hopopt : NULL), + newopt, newtype, &p); + ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt, + (opt ? opt->dst0opt : NULL), + newopt, newtype, &p); + ipv6_renew_option(IPV6_RTHDR, + (struct ipv6_opt_hdr **)&opt2->srcrt, + (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL), + newopt, newtype, &p); + ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt, + (opt ? opt->dst1opt : NULL), + newopt, newtype, &p); + + opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) + + (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) + + (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0); + opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0); + + return opt2; +} + +struct ipv6_txoptions *__ipv6_fixup_options(struct ipv6_txoptions *opt_space, + struct ipv6_txoptions *opt) +{ + /* + * ignore the dest before srcrt unless srcrt is being included. + * --yoshfuji + */ + if (opt->dst0opt && !opt->srcrt) { + if (opt_space != opt) { + memcpy(opt_space, opt, sizeof(*opt_space)); + opt = opt_space; + } + opt->opt_nflen -= ipv6_optlen(opt->dst0opt); + opt->dst0opt = NULL; + } + + return opt; +} +EXPORT_SYMBOL_GPL(__ipv6_fixup_options); + +/** + * fl6_update_dst - update flowi destination address with info given + * by srcrt option, if any. + * + * @fl6: flowi6 for which daddr is to be updated + * @opt: struct ipv6_txoptions in which to look for srcrt opt + * @orig: copy of original daddr address if modified + * + * Returns NULL if no txoptions or no srcrt, otherwise returns orig + * and initial value of fl6->daddr set in orig + */ +struct in6_addr *fl6_update_dst(struct flowi6 *fl6, + const struct ipv6_txoptions *opt, + struct in6_addr *orig) +{ + if (!opt || !opt->srcrt) + return NULL; + + *orig = fl6->daddr; + + switch (opt->srcrt->type) { + case IPV6_SRCRT_TYPE_0: + case IPV6_SRCRT_STRICT: + case IPV6_SRCRT_TYPE_2: + fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr; + break; + case IPV6_SRCRT_TYPE_4: + { + struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt; + + fl6->daddr = srh->segments[srh->segments_left]; + break; + } + default: + return NULL; + } + + return orig; +} +EXPORT_SYMBOL_GPL(fl6_update_dst); |